Multi-function Protection Relay
for Motors, Transformers, Blow-out Coils, Cables and Overhead Lines
MFR 7SJ551
Instruction Manual
Figure 1
Order No. G88700-C3527-07-7600
Illustration of the multi-function protection relay MFR 7SJ551
© Siemens Nederland N.V. 1998 Version R03-03
MFR 7SJ551
Introduction
s
Certificate of Conformity
This product is in conformity with the directive of the Council of the European Communities on the
harmonisation of the laws of the Member States relating to electromagnetic compatibility (EMC Council
Directive 89/336/EEC).
Conformity is proved by tests that have been performed according to article 10 of the Council Directive
in accordance with the generic standards EN 50081-2 and EN 50082-2 by Siemens Nederland N.V.
The device is designed and manufactured for application in industrial environment.
The device is designed in accordance with the standards of IEC 255 and VDE 0435 part 303.
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C88700-C3527-07-7600
MFR 7SJ551
Introduction
Contents
1 Introduction........................................................................................................................8
1.1 Application .................................................................................................................. 8
1.2 Features ...................................................................................................................... 8
1.3 Implemented functions .................................................................................................. 10
2 Design ..................................................................................................... 11
2.1
2.2
2.3
Arrangements ....................................................................................................... 11
Dimensions .......................................................................................................... 13
Ordering data ....................................................................................................... 16
2.3.1 Protection unit ...................................................................................................... 16
2.3.2 Interface unit........................................................................................................ 16
2.3.3 Operation and evaluation software .......................................................................... 17
2.3.4 Spare parts .......................................................................................................... 17
2.3.5 Surface mounting bracket ...................................................................................... 17
2.3.6.Optical cable ........................................................................................................ 17
3 Technical data ............................................................................................ 18
3.1
General data......................................................................................................... 18
3.1.1 Inputs / outputs .................................................................................................... 18
3.1.2 Electrical tests ...................................................................................................... 22
3.1.3 Mechanical stress test ........................................................................................... 24
3.1.4 Climatic stress tests .............................................................................................. 24
3.1.5 Service conditions ................................................................................................. 25
3.1.6 Interchangeability.................................................................................................. 25
3.1.7 Design ................................................................................................................. 25
3.2
Component data ................................................................................................... 26
3.3
Thermal overload protection ................................................................................... 26
3.3.1 Rotor thermal overload protection............................................................................ 26
3.3.2 Stator thermal overload protection........................................................................... 28
3.3.3 Thermal overload protection of non-rotating objects................................................... 29
3.4
Ambient temperature biasing (optional) .................................................................... 30
3.5
Start inhibit .......................................................................................................... 31
3.6
Locked rotor protection .......................................................................................... 32
3.7
Zero speed protection ............................................................................................ 32
3.8
Unbalance protection ............................................................................................. 33
3.9
Undercurrent protection ......................................................................................... 34
3.10
Overtemperature protection (optional) ...................................................................... 35
3.11
Low set overcurrent protection ............................................................................... 36
3.11.1 Definite time overcurrent protection....................................................................... 36
3.11.2 Inverse time overcurrent protection........................................................................ 37
3.11.3 Custom curve overcurrent protection ..................................................................... 39
3.12
High set overcurrent protection ............................................................................... 40
3.13
Curve switch ........................................................................................................ 41
3.14
Directional earthfault protection (optional) ................................................................ 42
3.15
Undervoltage protection (optional) ........................................................................... 44
3.16
Overvoltage protection (optional)............................................................................. 45
3.17
Breaker failure trip ................................................................................................. 46
3.18
Block................................................................................................................... 46
3.19
External command................................................................................................. 47
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MFR 7SJ551
3.20
Introduction
Ancillary functions ................................................................................................ 47
4 Method of operation .................................................................................... 49
4.1
4.2
Operation of the complete unit................................................................................ 49
Thermal overload protection ................................................................................... 50
4.2.1 Theoretical background.......................................................................................... 50
4.2.1.1 Single-body thermal overload model ............................................................... 50
4.2.1.2 Two-body thermal overload model.................................................................. 53
4.2.2 Rotor thermal overload protection............................................................................ 54
4.2.3 Stator thermal overload protection........................................................................... 55
4.2.4 Thermal overload protection of transformers, blow-out coils and cables........................ 56
4.3
Ambient temperature biasing (optional) .................................................................... 57
4.4
Start inhibit .......................................................................................................... 58
4.5
Emergency restart ................................................................................................. 59
4.6
Locked rotor protection.......................................................................................... 59
4.7
Zero speed protection ............................................................................................ 60
4.8
Motor start-up protection ....................................................................................... 60
4.9
Unbalance protection............................................................................................. 62
4.9.1 General................................................................................................................ 62
4.9.2 Unbalance protection of motors .............................................................................. 63
4.10
Undercurrent protection ......................................................................................... 63
4.10.1 General .............................................................................................................. 63
4.10.2 Motor undercurrent protection .............................................................................. 64
4.11
Overtemperature protection (optional) ...................................................................... 64
4.12
Low set overcurrent protection ............................................................................... 65
4.12.1 Definite time overcurrent protection....................................................................... 65
4.12.2 Inverse time overcurrent protection ....................................................................... 65
4.12.3 Custom curve overcurrent protection ..................................................................... 66
4.13
High set overcurrent protection ............................................................................... 66
4.13.1 Fast busbar protection using the reverse interlock scheme ........................................ 67
4.14
Curve switch........................................................................................................ 67
4.15
Directional earth fault protection (optional) ............................................................... 67
4.15.1 Cos f determination ............................................................................................. 68
4.15.2 Sin f determination .............................................................................................. 69
4.15.3 Sensitivity emprovement by shifting the symmetry axis............................................ 69
4.15.4 Correcting the angular error of the core balance transformer ..................................... 69
4.15.5 Earth fault location .............................................................................................. 70
4.16
Undervoltage protection (optional) ........................................................................... 70
4.17
Overvoltage protection (optional) ............................................................................ 71
4.18
Breaker failure trip................................................................................................. 71
4.19
Block................................................................................................................... 72
4.20
External command ................................................................................................ 72
4.21
Circuit breaker position .......................................................................................... 72
4.22
Ancillary functions ................................................................................................ 72
4.22.1 Processing of annunciations.................................................................................. 72
4.22.2 Fault event data storage and transmission (optional) ................................................ 73
4.22.3 Operational value measurements ........................................................................... 74
4.22.4 Demand ampere meter ......................................................................................... 74
4.22.5 Test facilities ...................................................................................................... 74
4.22.6 Hardware monitoring ........................................................................................... 74
5 Installation instructions ................................................................................ 76
5.1
Unpacking and repacking ....................................................................................... 76
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MFR 7SJ551
5.2
6
Introduction
Preparations ......................................................................................................... 76
5.2.1 Mounting and connections ..................................................................................... 77
5.2.2 Checking the rated data ......................................................................................... 77
5.2.3 Checking the (optional) interface unit transmission link............................................... 77
5.2.4 Connections ......................................................................................................... 78
5.2.5 Checking the connections ...................................................................................... 78
Operating instructions....................................................................... 80
6.1
6.2
Safety precautions ................................................................................................ 80
Dialogue with the relay .......................................................................................... 80
6.2.1 Display panel ........................................................................................................ 80
6.2.2 Keyboard ............................................................................................................. 80
6.2.3 LED indicators ...................................................................................................... 81
6.2.4 Operation with a personal computer ........................................................................ 81
6.2.5 Front view of the relay........................................................................................... 82
6.3
Parameterizing procedure ....................................................................................... 83
6.3.1 Menu structure ..................................................................................................... 83
6.3.2 Initial display ........................................................................................................ 84
6.4
Main menu (OFF LINE) ........................................................................................... 84
6.5
SETTINGS menu ................................................................................................... 85
6.6
Settings for DEVICE DATA ..................................................................................... 86
6.6.1 Non-rotating device ............................................................................................... 87
6.6.2 Rotating device..................................................................................................... 87
6.7
Settings for CHANNELS ......................................................................................... 89
6.8
Settings for PROTECTIONS..................................................................................... 93
6.8.1 THERMAL OVERLOAD protection............................................................................ 94
6.8.1.1 Thermal overload protection for rotating objects............................................... 94
6.8.1.2 Thermal overload protection for non-rotating objects ........................................ 97
6.8.2 AMBIENT TEMPERATURE BIASING (optional) ........................................................... 99
6.8.3 START INHIBIT ................................................................................................... 100
6.8.4 EMERGENCY RESTART........................................................................................ 102
6.8.5 OVERTEMPERATURE protection (optional).............................................................. 103
6.8.6 UNDERCURRENT protection ................................................................................. 104
6.8.7 LOW SET OVERCURRENT protection ..................................................................... 105
6.8.7.1 Definite time phase fault overcurrent protection ............................................. 106
6.8.7.2 Definite time earth fault overcurrent protection .............................................. 108
6.8.7.3 Inverse time phase fault overcurrent protection .............................................. 109
6.8.7.4 Inverse time earth fault overcurrent protection ............................................... 110
6.8.7.5 Custom curve overcurrent protection............................................................ 111
6.8.8 HIGH SET OVERCURRENT protection .................................................................... 113
6.8.9 UNBALANCE protection ....................................................................................... 114
6.8.10 DIRECTIONAL EARTHFAULT protection (optional) ................................................. 115
6.8.11 LOCKED ROTOR protection ................................................................................ 118
6.8.12 ZERO SPEED protection ..................................................................................... 118
6.8.13 UNDERVOLTAGE protection (optional) ................................................................. 119
6.8.14 OVERVOLTAGE protection (optional) ................................................................... 119
6.8.15 BREAKER FAILURE TRIP..................................................................................... 120
6.8.16 CURVE SWITCH ............................................................................................... 122
6.8.17 BLOCK............................................................................................................. 123
6.8.18 EXTERNAL COMMAND...................................................................................... 125
6.8.19 CIRCUIT BREAKER POSITION ............................................................................. 125
6.9
Settings for TRANSIENT DATA ............................................................................. 127
6.10
Settings for the REAL TIME CLOCK ....................................................................... 127
6.11
MARSHALLING of binary inputs, binary outputs and LED indicators............................ 128
6.11.1 General ............................................................................................................ 128
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MFR 7SJ551
Introduction
6.11.2 Marshalling of the BINARY INPUTS...................................................................... 129
6.11.3 Marshalling of the OUTPUT RELAYS .................................................................... 132
6.11.4 Marshalling of the LED INDICATORS (optional)...................................................... 136
6.12
Settings for SERIAL COMMUNICATION (optional).................................................... 137
6.13
Putting the relay into operative mode (ON LINE) ...................................................... 139
6.14
Annunciations .................................................................................................... 140
6.14.1 Introduction...................................................................................................... 140
6.14.2 MEASURED VALUES ......................................................................................... 141
6.14.3 COUNTERS ...................................................................................................... 143
6.14.4 ALARM / TRIP DATA ......................................................................................... 143
6.14.5 DEMAND AMPERE METER ................................................................................. 146
6.14.6 RUNNING HOURS ............................................................................................. 147
6.14.7 MANUFACTURER DATA .................................................................................... 148
6.15
Resetting all settings to factory settings................................................................. 149
6.16
Testing and commissioning .................................................................................. 151
6.16.1 General ............................................................................................................ 151
6.16.2 Testing the measurement of operational values ..................................................... 152
6.16.3 Testing the motor status .................................................................................... 153
6.16.4 Testing the rotor thermal overload protection ........................................................ 153
6.16.5 Testing the stator thermal overload protection ...................................................... 156
6.16.6 Testing the thermal overload protection of non-rotating objects ............................... 159
6.16.7 Testing the ambient temperature biasing .............................................................. 161
6.16.8 Testing the start inhibit ...................................................................................... 162
6.16.9. Testing the emergency restart............................................................................ 163
6.16.10 Testing the overtemperature protection .............................................................. 163
6.16.11 Testing the undercurrent protection ................................................................... 163
6.16.12 Testing the low set overcurrent protection.......................................................... 164
6.16.12.1 Testing the definite time overcurrent protection ......................................... 164
6.16.12.2 Testing the inverse time overcurrent protection .......................................... 165
6.16.12.3 Testing the custom curve overcurrent protection ........................................ 165
6.16.13 Testing the high set overcurrent protection ......................................................... 166
6.16.14 Testing the unbalance protection ....................................................................... 166
6.16.15 Testing the locked rotor protection .................................................................... 167
6.16.16 Testing the zero speed protection ...................................................................... 168
6.16.17 Testing the directional earthfault protection ........................................................ 168
6.16.18 Testing the undervoltage protection ................................................................... 169
6.16.19 Testing the overvoltage protection..................................................................... 169
6.16.20 Testing the breaker failure trip........................................................................... 170
6.16.21 Testing the curve switch .................................................................................. 170
6.16.22 Testing the block function ................................................................................ 172
6.16.23 Testing the external command .......................................................................... 173
6.16.24 Testing the circuit breaker position .................................................................... 173
6.17
Commissioning using primary tests........................................................................ 174
6.17.1 Current circuit checks ........................................................................................ 174
6.17.2 Checking the reverse interlock scheme (if used) .................................................... 174
6.17.3 Testing the switching of binary inputs and outputs ................................................ 175
6.17.4 Tripping test including circuit breaker................................................................... 176
6.17.5 Putting the relay into operation ........................................................................... 176
7
Maintenance and trouble shooting .................................................... 177
7.1
7.2
7.3
7.4
7.5
General.............................................................................................................. 177
Routine checks ................................................................................................... 177
Self test ............................................................................................................ 177
Replacing the real time clock module ..................................................................... 178
Power failure test................................................................................................ 179
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MFR 7SJ551
7.6
Introduction
Trouble shooting ................................................................................................... 176
7.6.1 Replacing the mini-fuse ........................................................................................ 180
8
Repairs ......................................................................................... 182
9
Storage......................................................................................... 183
Appendix ......................................................................................................... 184
A.
B.
C.
D.
E.
F.
General diagrams ................................................................................................ 185
Typical wiring diagrams........................................................................................ 190
Motor application example.................................................................................... 192
Default values..................................................................................................... 199
Setting tables ..................................................................................................... 204
Advice of return 7SJ55........................................................................................ 224
NOTE:
This instruction manual does not intend to cover
all details in equipment, nor to provide for every
possible contingency occurring in connection
with installation, operation or maintenance.
Should further information be desired or should
particular problems arise which are not covered
sufficiently for the purchaser’s purpose, the
matter should be referred to the local Siemens
sales office.
C88700-C3527-07-7600
The contents of this instruction manual shall not
become part nor modify any prior or existing
agreement, commitment or relationship. The
sales contract contains the entire obligations of
Siemens. The warranty contained in the
contract between the parties is the sole
warranty of Siemens. Any statements contained
herein do not create new warranties nor modify
the existing warranty.
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MFR 7SJ551
1
Introduction
1.1
Application
The relay MFR 7SJ551 is a modern protection
unit for low, medium and high voltage electricity
network components like motors, transformers,
blow-out coils, cables, overhead lines and
capacitor banks. The treatment of the electricity
network star point is of no concern. The main
applications of MFR 7SJ551 are:
− protection against too high temperature
− protection against short circuit situations.
Too high temperatures in electric components
cause isolation ageing, which leads to lifetime
shortening of the component. Temperature
protection is accompanied with relatively low
currents and long time settings. Excessive
temperature rising can appear because of:
− overload
− asymmetrical load or phase loss
− underload (fans and pumps)
− stalled rotor
− multiple starting and tripping
− starting too long.
Short-circuits in electric components are
characterised by very high currents. These
currents are acceptable only for short periods of
1.2
Introduction
time because of the acting short-circuit
strengths.
Besides phase and earth short-circuit protection
MFR 7SJ551 is used as earth fault direction
protection for isolated, compensated and highohmic earthed networks.
Furthermore MFR 7SJ551 can be put on as
back-up protection for differential protection (for
generators, motors, transformers, lines or bus
bars) and distance protection.
MFR 7SJ551 provides a complete statistical
record of the protected electric component. The
number of alarms and trips is recorded in a
memory. All relevant alarm and trip data such
as origin, day and time, duration and trip levels
can be read off on the display. During an alarm
or trip event the magnitudes of the
instantaneous values are stored for a period of 3
seconds. This information can be visualized with
a PC connected to either the RS-485 or the fibre
optic interface. Furthermore, the serial
interfaces can be used for incorporating MFR
7SJ551 in a substation management system.
For data transmission an standardized protocol
is used in accordance with IEC 870-5.
Features
− Controller system with powerful
microcontroller;
− completely digitally measured value
processing and control from data acquisition
and digitizing of the measured values up to
the trip and close decision for the circuit
breaker;
− all current and voltage protection functions
(except thermal overload protection which is
based on True RMS measurement) based on
the values of the nominal frequency (digital
Fourier filtering); the direct current
component and the higher harmonic
components are suppressed and do not
disturb the protection functions;
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− complete galvanic and reliable separation of
the internal processing circuits from the
measurement, control and supply circuits of
the system, with screened analogue input
transducers, binary input and output modules
and DC converter;
− complete scope of functions required for the
protection of motors, transformers and
cables;
− separate setting tables for the protection of
rotating and non-rotating network
components;
C88700-C3527-07-7600
MFR 7SJ551
− thermal overload protection of rotating
devices:
• separate thermal replica for stator and
rotor based on True RMS current
measurement
• up to 2 heating time constants for the
stator thermal replica
• separate cooling time constants for stator
and rotor thermal replica
• ambient temperature biasing of thermal
replica
• incorporation of additional heating effects
of asymmetrical currents;
− thermal overload protection of non-rotating
devices:
• up to 2 heating time constants with
extremely wide setting ranges for optimal
thermal protection of cables and
transformers
• externally adjustable time constant
• ambient temperature biasing of thermal
replica;
− connection of up to 8 temperature sensors
(optional);
− multi-curve overcurrent and earth fault
protection:
• insensitive for transients and DC
components
• separate two-stage tripping characteristics
for phase and earth elements
• four selectable internationally standardized
(BS 142, IEC 255-4) tripping
characteristics for phase elements:
normally inverse, very inverse, extremely
inverse and definite time
C88700-C3527-07-7600
Introduction
• two additional tripping characteristics for
the earth element: long time earth fault
and residual dependent time;
• custom curves instead of standard curves
can be programmed to offer optimal
flexibility for both phase and earth
elements;
− curve switch and blocking functions offering
an adaptive feature to change the relay
characteristics according to prevailing
system conditions (like motor status ‘start’
or ‘running’);
− equipped with highly sophisticated protection
algorithms which offer optimal flexibility in
grading with other protection relays and with
the thermal limit curves of primary
components;
− software matrix for signalling and tripping
relays;
− real time clock: last 3 events are stored with
real time stamps of alarm and trip data;
− continuous monitoring of the measured
values and the hardware and software of the
relay;
− storage of fault data, storage of
instantaneous values during a fault for fault
recording;
− communication with a PC or a substation
management system through an RS485
interface or a fibre optic interface (optional)
using an IEC 870-5-103 protocol.
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MFR 7SJ551
1.3
Introduction
Implemented functions
MFR 7SJ551 contains the following functions.
Protection of motors
Rotor thermal overload protection
Stator thermal overload protection
Ambient temperature biasing (optional)
Start inhibit
Emergency restart
Locked rotor protection (failure to
accelerate)
Zero speed protection
Unbalance protection
Undercurrent protection
Overtemperature protection (optional)
Definite time overcurrent protection
Inverse time overcurrent protection
Custom curve overcurrent protection
High set overcurrent protection
Curve switch
Directional earth fault protection (optional)
Undervoltage protection (optional)
Overvoltage protection (optional)
Breaker failure trip
Block
External command
Circuit breaker position
Self-monitoring
Real time clock
Event recording
Fault recording
Motor statistical data
LED indication
Operational values measurement
Running hours counter
PC programming possibility (optional)
Substation management system connection
(optional)
ANSI Protection of transformers
blow-out coils
cables
overhead lines
capacitor banks
49R
49
Thermal overload protection
Ambient temperature biasing (optional)
86
ANSI
49
48
14
46
37
51
51G
51N
51
51G
51N
50
50G
67N
27
59
Unbalance protection
Undercurrent protection
Overtemperature protection (optional)
Definite time overcurrent protection
Inverse time overcurrent protection
Custom curve overcurrent protection
High set overcurrent protection
Curve switch
Directional earth fault protection (optional)
Undervoltage protection (optional)
Overvoltage protection (optional)
Breaker failure trip
Block
External command
Circuit breaker position
Self-monitoring
Real time clock
Event recording
Fault recording
Component statistical data
LED indication
Operational values measurement
46
37
51
51G
51N
51
51G
51N
50
50G
67N
27
59
PC programming possibility (optional)
Substation management system connection
(optional)
For a detailed description please refer to chapter 4.
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MFR 7SJ551
2
Design
2.1
Arrangements
The complete relay is fitted in a draw-out
module of Double Europe Format. This module
is installed in a housing 7XP20.
The optional interface unit (see figure 2.1)
provides:
− 8 x 3 screw terminals for up to 8
temperature sensors;
− 9 pole female connector for the RS-485;
− a transceiver and a transmitter fibre optic
interface.
Two types of housings can be delivered:
− 7SJ551*-*A***- in horizontal housing
7XP20 for panel flush mounting or cubicle
installation.
− 7SJ551*-*B***- in vertical housing 7XP20
for panel flush mounting or cubicle
installation.
The housing has full sheet-metal covers as well
as a removable front cover with transparent
plastic window for panel mounting.
Guide rails are built in for the support of the
plug-in module. On the top and bottom plates of
the housing, contact areas which are electrically
connected to the housing are installed to mate
with the earthing springs of the module.
Connection to earth is made before the plugs
G88700-C3527-07-7600
Design
make contact. An earth screw has been
provided on the back of the housing.
The heavy-duty current plug connectors provide
automatic shorting of the current transformer
circuits whenever the module is withdrawn.
All external signals are connected to combined
screw snap-on terminals on the backside of the
housing. For field wiring, the use of the screwed
terminals is recommended; snap-in connection
requires special tools. See figure 2.2.
The plug modules are labelled according to their
mounting position by means of a grid system
(e.g. XE-IV.2). The individual connections within
a module are numbered consecutively from left
to right (when viewed from the back).
The degree of protection for the housing is
IP51, for the terminals IP21.
For dimensions please refer to figure 2.3.
For surface mounting, surface mounting
brackets are deliverable in two sizes. The short
one (depth 271 mm) is used for protection units
without mounted interface module. The long
one (depth 288 mm) is used with mounted
interface module.
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MFR 7SJ551
Design
Optical fibre connectors:
Integrated FSMA connector, with
ceramic post, e.g. for glass fibre
62.5/125 μm
Figure 2.1
Interface unit
Figure 2.2
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Connection plugs (rear view)
G88700-C3527-07-7600
MFR 7SJ551
2.2
Design
Dimensions
Figure 2.3 shows the dimensions of the housing.
7SJ551 housing for panel flush mounting or cubicle installation 7XP20
29.6
202
100
86.4
30
244
255.9
115
interface unit (optional)
86.4
recess hole (4 x)
29.6
mounting hole (4 x)
202
60
30
101
115
interface unit (optional)
Panel
cut-out
Heavy-current connectors:
Screwed terminal for maximum 4 mm2.
Twin spring crimp connector in parallel for maximum 2.5 mm2.
246.5
Further connectors:
Screwed terminal for maximum 1.5 mm2.
Twin spring crimp connector in parallel for maximum 1.5 mm2.
Dimensions in mm
M4
G88700-C3527-07-7600
M5
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MFR 7SJ551
Figure 2.3
Design
Dimensions for housing 7XP20 for panel flush mounting or cubicle installation
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G88700-C3527-07-7600
MFR 7SJ551
Design
Figure 2.4 shows the surface mounting bracket.
100
271 or
288
271 or
288
140
254.5
247
100
120
233
Figure 2.4
Dimensions for surface mounting bracket for panel surface mounting
G88700-C3527-07-7600
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MFR 7SJ551
Design
MFR 7SJ551 can be mounted in standard 19 inch double height racks. Figure 2.5 shows the relevant
dimensions.
300
recess holes (5 mm)
60
255.9
265
mounting holes
Figure 2.5
86.8
Mounting of MFR 7SJ551 in standard 19”racks
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G88700-C3527-07-7600
MFR 7SJ551
G88700-C3527-07-7600
Design
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MFR 7SJ551
2.3
Ordering data
2.3.1
Protection unit
Design
7
Multi-Function Protection Relay
7SJ551
⏐
Rated current; rated frequency
R, T, e 1/5 A, 50/60 Hz
R, S, T, e 1/5 A, 50/60 Hz
R, T 1/5 A, esensitive 1 A, 50/60 Hz
R, S, T 1/5 A, esensitive 1 A, 50/60 Hz
Auxillary voltage
24 - 60 V DC
110 - 250 V DC / 110 - 230 V AC
Construction
in horizontal housing 7XP20 for panel flush
mounting or cubicle mounting
in vertical housing 7XP20 for panel flush mounting
or cubicle mounting
Operating language
English
German
Connections
standard version
extended input / output: 3 extra inputs, 2 extra
outputs,
4 extra LED indicators
extended input / output: 3 extra inputs, 2 extra
outputs,
4 extra LED indicators + voltage functions (single
phase)
extended input / output: 3 extra inputs, 2 extra
outputs,
4 extra LED indicators + voltage functions (single
phase) or earth fault direction
(only in combination with esensitive 1 A)
Interface module
without
RS485 + optical FSMA-interface
RS485 + optical FSMA-interface + connection for
2 RTD elements
RS485 + optical FSMA-interface + connection for
8 RTD elements
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8
9
7
1
2
3
4
10
11
A
⏐
⏐
⏐
⏐
⏐
⏐
⏐
8
1
2
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
9
A
B
12
0
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
11
0
1
13
14
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
⏐
-
14
0
1
2
3
15
A
B
C
D
G88700-C3527-07-7600
MFR 7SJ551
2.3.2
Design
Interface unit
The interface unit can be ordered separately with the following ordering numbers. It is always possible
to equip the protection unit with the interface unit later on.
RS-485 + optical FSMA-interface
G88700-C3526-L130
...................................................
RS-485 + optical FSMA-interface + connection for 2 RTD elements .. G88700-C3526-L131
RS-485 + optical FSMA-interface + connection for 8 RTD elements .. G88700-C3526-L132
2.3.3
Operation and evaluation software
Operation and evaluation software 7SJ551 Communication Utility
English ........................................................................................ G88700-H3587-R100
German ....................................................................................... G88700-H3587-R200
2.3.4
Spare parts
Complete housing for panel flush mounting or cubicle installation .......
Front cap .....................................................................................
Enbedded software English 1).........................................................
Enbedded software German 1)........................................................
G88700-C3526-L153
G88080-W-350-L110
G88080-C3526-L9X1
G88080-C3526-L9X0
1) By ordering software please give the serienumber of the relay
2.3.5
Surface mounting bracket
Surface mounting bracket long (depth 288 mm) ............................... G88700-C3526-L154
Surface mounting bracket short (depth 271 mm) .............................. G88080-X504-L110
2.3.6
Optical cable
Optical cable complete (5 meter)..................................................... UNSIE-PC-5M
Notebook connector....................................... .............................. UN5381-1B
G88700-C3527-07-7600
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MFR 7SJ551
Technical data
3
Technical data
3.1
General data
3.1.1
Inputs / outputs
Setting ranges
Full scale phase current
Imax
7
/ 14
/ 28
A
Full scale regular earth current
Imax
7
/ 14
/ 28
A
0.35
/ 0.7
/ 1.4
A
Full scale sensitive earth current Ie max
Current transformer ratio
1
to 9999
Voltage transformer ratio
1
to 9999
Measuring circuits
Rated current In
(3 x IPh + 1 x Ie)
1 A or 5 A
Rated current Ie sensitive
1A
Rated voltage Un
(1 x U)
100 V or 110 V
Rated frequency fn
50 Hz or 60 Hz (selectable)
Burden at In / Un
− 1 A current inputs
− 5 A current inputs
− 1 A sensitive earth current input
− voltage input
≤ 0.01
≤ 0.15
≤ 0.2
≤0.05
VA
VA
VA
VA
100
30
6
250
x
x
x
x
In
In
In
In
for 1 s
for 10 s
continuous
one half cycle
75
20
4
200
x
x
x
x
In
In
In
In
for 1 s
for 10 s
continuous
one half cycle
Overload capability phase current and regular earth
current path
− thermal (RMS)
− dynamic (pulse current)
Overload capability sensitive earth current path
− thermal (RMS)
− dynamic (pulse current)
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C88700-G1176-U810-3
MFR 7SJ551
Technical data
Accuracy
Phase currents and regular earth currents
x In
− for full scale current Imax = 7
• 0.05
to 0.5
x In
• 0.5
to 7
x In
− for full scale current Imax = 14
x In
• 0.1
to 1
x In
• 1
to 14
x In
− for full scale current Imax = 28
x In
• 0.2
to 2
x In
• 2
to 28
x In
Sensitive earth current
− for full scale current Ie max
• 0.003 to0.025
• 0.025 to0.35
− for full scale current Ie max
• 0.005 to0.05
• 0.05
to 0.7
− for full scale current Ie max
• 0.01
to 0.1
• 0.1
to 1.4
=0.35 x In
x In
x In
=0.7
x In
x In
x In
=1.4
x In
x In
x In
Voltage
• 0.005
• 0.01
x Un
x Un
to0.01
to 1.2
≤0.025
≤ 5
x In
% of setting value
≤0.05
≤ 5
x In
% of setting value
≤0.1
≤ 5
x In
% of setting value
≤0.00125
≤ 5
x In
% of setting value
≤0.0025
≤ 5
x In
% of setting value
≤0.005
≤ 5
x In
% of setting value
≤0.0005
≤ 5
x Un
% of setting value
Auxiliary supply voltage
Power supply via integrated AC/DC or DC/DC
converter
Rated auxiliary voltage Uh
24
Permissible variations
19.2 - 72 V DC
Superimposed AC voltage,
peak to peak
≤ 12
6
Power consumption
− quiescent
− energized
− picked up
Bridging time during failure or short circuit of
auxiliary voltage
C88700-C3527-07-7600
- 60 V DC
%
%
110 - 250 V
DC
88 - 300 V DC
110 - 230 V
AC
88 - 256 V AC
at rated voltage
at limits of admissible voltage
15
W
20
W
17/22 W
20
500
40
500
40
500
ms
ms
ms
ms
ms
ms
at
at
at
at
at
at
24
60
110
250
110
230
V
V
V
V
V
V
DC
DC
DC
DC
AC
AC
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Technical data
Heavy duty command and signal contacts
Command (trip) and signal relays
− basic version
• number
• contacts per relay
− version with extended I/O
• number
• contacts per relay
Switching capacity
Switching voltage
MAKE
BREAK
DC
AC
Permissible current
4 command or signal relays
1 monitor relay
output 1 - 4 : 1 NO
monitor
: 1 NC
6 command or signal relays
1 monitor relay
output 1
: 2 NO
output 2 - 5 : 1 NO
monitor
: 1 NC
1000
30
300
250
5
30
W/VA
W/50 VA
V
V
A continuous
A for 0.5 sec
Binary control inputs, number
− basic version
− version with extended I/O
2 (can be marshalled)
5 (can be marshalled)
Operating voltage
Minimum signal time
24 - 250 V DC
110 - 230 V AC
approx. 3 mA, independent of the operating
voltage
≥
5 ms
Detection time
≤ 10 ms
Current consumption
Interface module
− RS485 serial interface
• Floating interface for data communication
with PC or substation management system
• Protocol standards
• Transmission speed
•
•
•
•
Hamming distance
Connection
Transmission distance
Test voltage
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isolated by opto-couplers
IEC 870-5 with VDEW/ZVEI recommendation or
protocol DIN 19244
2400 Baud
4800 Baud
9600 Baud
19200 Baud
38400 Baud
d=4
9 pole female D connector
≤ 1000 m
500 V DC, 2 kV with rated frequency for 1 min.
C88700-G1176-U810-3
MFR 7SJ551
− Fibre optic serial interface
• Floating interface for data communication
with a control centre
• Protocol standards
• Transmission speed
• Hamming distance
• Connection
•
•
•
•
Optical wave length
Permissible line attenuation
Transmission distance
Signal setting
− Temperature sensors
• Floating interface isolated from the main
relay and the serial interfaces
• Number of temperature sensors
• Type
•
•
•
•
•
Temperature range
Connection terminals
Distance
Cable resistance
Accuracy
C88700-C3527-07-7600
Technical data
isolated according IEC 874-2
IEC 870-5 with VDEW/ZVEI recommendation or
protocol DIN 19244
2400 Baud
4800 Baud
9600 Baud
19200 Baud
38400 Baud
d=4
integrated F-SMA connector for direct optical fibre
connection e.g. glass fibre 62.5/125 μm
820 nm
max. 8 dB
2 km
factory setting ‘light off’ (configurable with 2
jumpers)
2 or 8
Pt100 or
Ni100 or
Ni120
0 to 200°C
3 for each sensor
≤ 150 m
≤ 25 Ω pro wire
≤
3 °C
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MFR 7SJ551
3.1.2
Technical data
Electrical tests
Standards for general product testing
− Test standards
EN 55011
EN 68-2
IEC 255-5
IEC 255-22-1
IEC 255-6
IEC 801-2
IEC 801-3
IEC 801-4
IEC 801-5
VDE 0435 part 303
DIN 40040
DIN 40048-8
Insulation tests
− High voltage test (routine test)
injecting 50 Hz, 2 kV AC. for 1 minute between
the housing and one pair of shortened circuit
terminals (auxiliary power, current inputs, voltage
input, external control inputs and output contacts);
all the other pairs of circuit terminals are connected
to the housing; this successively for all pairs of
circuit terminals
− Measurement of insulation resistance
test voltage 500 V DC
− Impulse voltage test (type test)
injecting 3 positive and 3 negative 5 kV impulse
voltages both common mode and differential mode
(1.2/50 μs between tested circuit and earth)
test voltage 500 V DC
− Repeated measurement of isolation resistance
− Conclusions
no flash-over or break-down between tested circuit
and earth or between tested circuit and any other
terminal; isolation resistance in all cases exceeded
100 MΩ
Disturbance immunity tests for the auxiliary supply voltage
− Proper operation range of input voltages
24 - 60 V DC
110 - 250 V DC
110 - 230 V AC
19.2 - 72 V DC
88 - 300 V DC
88 - 276 V AC
Spike test (recommended by KEMA)
−
−
−
−
Rise time
Half amplitude width
Ri
Differential mode voltage on auxiliary supply
voltage terminal
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150
50
5
1
ns
μs
Ω
kV
C88700-G1176-U810-3
MFR 7SJ551
Technical data
Disturbance immunity of the current and voltage frequency
− Maintenance of accuracy
• for the 50 Hz model
• for the 60 Hz model
45 Hz to 55 Hz
55 Hz to 65 Hz
Harmonic immunity
Immunity level to high frequency harmonic current
waveforms
− 10% 3th harmonic
− 10% 5th harmonic
influence on operating current < 1%
influence on operating current < 1%
High frequency disturbance test
−
−
−
−
−
−
−
Standard
Test frequency
Ri
Repetition rate
Test duration
Common mode voltage
Differential mode voltage
IEC 256-6/255-22-1
1 MHz
200 Ω
400 shots/s
2s
2.5 kV
1 kV
Electrostatic discharge test
− Standard
− Level
− Discharge voltage
IEC 801-2
3
4 kV
Radiated electromagnetic fields test
−
−
−
−
−
Standard
Level
Test frequency
Magnetic field strength
Directions
IEC 801-3
3
0.15 - 300 Mhz
10 V/m
front, top and side
Electrical fast transient test
Immunity to noise generated from high energy
transient generator
− Standard
− Level
− Rise time
− Half amplitude width
− Ri
− Repetition rate
− Burst duration
− Burst period
− Test duration
− Common mode voltage
• between circuit and case
• between auxiliary supply and case
C88700-C3527-07-7600
IEC 801-4
3
5 ns
50 ns
50 Ω
5 kHz
15 ms
300 ms
10 s
2 kV
4 kV
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MFR 7SJ551
Technical data
Radio frequency interference test
− Standard
− Line interference on all terminals
− Radiation
EN 55011
0.15 - 300 Mhz
30 - 1000 MHz
Surge test
− Standard
3.1.3
−
−
−
−
−
Mechanical stress test
Standard
Frequency
Amplitude
Acceleration
Repetition rate
3.1.4
IEC 801-5
IEC 68-2-6 and DIN 40048-8
10 - 55 Hz
15 mm
2G
20 sweeps in 3 directions
Climatic stress tests
Permissible ambient temperature
−
−
−
−
During service
During storage
During transport
Storage and transport
-10 °C to +55 °C
-25 °C to +70 °C
-25 °C to +55 °C
standard works packing
Humidity class
− Standards
DIN 40040, Class F
IEC 68-2-30
Cyclic damp heat test
− Standards
− Cycle number
− Temperature range
− Relative humidity
DIN 40040, Class F
IEC 68-2-30
6
25 °C to 55 °C
95%
Storage test (recommended by KEMA)
− Duration
16 hours at -25 °C and
16 hours at +70 °C
We recommend that all units are installed such that they are not subjected to direct sunlight, nor to
large temperature fluctuations which may give rise to condensation.
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C88700-G1176-U810-3
MFR 7SJ551
C88700-C3527-07-7600
Technical data
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.1.5
Service conditions
MFR 7SJ551 is designed for use in industrial
environment, for installation in standard relay
rooms and compartments so that with proper
installation electro-magnetic compatibility
(EMC) is ensured. The following should also be
heeded:
− All contactors and relays which operate in
the same cubicle or on the same relay panel
as the MFR 7SJ551 should, as a rule, be
fitted with suitable spike quenching
elements.
− All external connection leads in substations
from 100 kV upwards should be screened
with a screen capable of carrying power
currents and should be earthed at both sides.
3.1.6
Technical data
No special measures are normally necessary
for substations of lower voltages.
− It is not permissible to withdraw or insert
individual modules under voltage. In the
withdrawn condition, some components are
electrostatically endangered; during handling
the standards for electrostatically
endangered components must be observed.
The modules are not endangered when
plugged in.
WARNING! The relay is not designed for use in
residential, commercial or light-industrial
environment as defined in EN 50081.
Interchangeability
− Devices:
MFR 7SJ551 protective devices in housings
or in factory fitted subracks are always
tested as complete units and are
interchangeable as complete units without
restrictions.
interchangeable.
When it is necessary to exchange a device or
module, the complete parameter assignment
should be repeated. Respective notes are
contained in Chapters 5 and 6.
− Modules:
MFR 7SJ551 plug-in modules are
3.1.7
Design
Housing
7XP20; refer to section 2.1
Dimension
refer to section 2.2
Weight
− protection unit
− interface unit
approximately 4
approximately0.5
Degree of protection according to DIN 40050
− Housing
− Terminals
IP51
IP21
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kg
kg
C88700-G1176-U810-3
MFR 7SJ551
3.2
Technical data
Component data
Setting ranges / steps
Full load current
− Setting range
− Steps
• 0.05
≤ Iflc/In
•
1
≤ Iflc/In
•
10
≤ Iflc/In
Iflc/In
<
<
≤
to
28
0.05
to
1
0.05
to
28
0.001
0.01
0.1
1
10
28
No load current (motors)
− Setting range
0.05
Ino load/In
3.3
Thermal overload protection
3.3.1
Rotor thermal overload protection
(steps 0.001)
Setting ranges / steps
Permissible start-up current
− Setting range
Istart/In
− Steps
• 0.05
≤ Istart/In <
1
10
•
1
≤ Istart/In <
28
•
10
≤ Istart/In ≤
Permissible start-up time
− Setting range
− Steps
•
1
≤ tstart
<
<
•
10
≤ tstart
• 100
≤ tstart
≤
tstart
10 s
100 s
200 s
0.001
0.01
0.1
1
to 200
0.01
0.1
1
s
s
s
Permissible number of starts
− from warm motor condition
− from cold motor condition
nwarm
ncold
1
1
to
to
15
15
Unbalance factor
kinv
0
to
10
Cooling down factor rotor
cstop,rotor
1
to
10
C88700-C3527-07-7600
s
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Technical data
Trip time calculation
ncold
ncold − nwarm
krotor =
τ rotor =
− ncold ⋅ tstart
⎛
k2 ⋅ I2flc ⎞
⎟
ln⎜1 − rotor
I2start ⎠
⎝
I2heating = I2normal + kinv ⋅ I2inverse
⎛ −t ⎞
I2th,rotor (t) = I2heating + [I2th,rotor (t = 0) − I2heating ] ⋅ exp⎜
⎟
⎝ τ rotor ⎠
θth,rotor =
t = t trip
k2rotor ⋅ I2flc − I2th,rotor
k2rotor ⋅ I2flc
for
⋅ 100%
θth,rotor = 0
⇓
t trip = τrotor
2⎞
⎛ ⎛ I ⎞2 ⎛ I
⎜ ⎜ ⎟ − ⎜ preload ⎞⎟ ⎟
⎜ ⎝I ⎠
⎝ Iflc ⎠ ⎟
⋅ ln⎜ flc
⎟
2
⎜ ⎛ I ⎞
⎟
2
⎜ ⎜ ⎟ − krotor ⎟
⎝ ⎝ Iflc ⎠
⎠
(Iheating = I )
krotor
τrotor
Iflc
Iheating
Inormal
Iinverse
Ith,rotor
θth,rotor
ttrip
I
current
Ipreload
Accuracy trip time
¡Error! Argumento de modificador desconocido.
overload factor rotor
thermal time constant rotor
full load current
equivalent heating current
normal component of the phase currents
inverse component of the phase currents
thermal load current rotor
thermal reserve rotor
trip time
actual symmetric three phase step
preload current rotor
the higher value of 1 s and 2% of τrotor
C88700-G1176-U810-3
MFR 7SJ551
3.3.2
Technical data
Stator thermal overload protection
Setting ranges / steps
Overload factor stator
kstat
Thermal time constant stator 1
Thermal time constant stator 2
− Steps for τ1,stat and τ2,stat
τ1,stat
τ2,stat
•
•
•
1
10
100
≤ tstart
≤ tstart
≤ tstart
<
<
≤
10 s/min/h
100 s/min/h
999 s/min
1
to 1.5
1 s to 999 min
1 s to 999 min
switchable between seconds, minutes
and hours
0.01
s/min/h
0.1
s/min/h
1
s/min
Weighing factor
pweight
0
to
1
Cooling down factor stator
cstop,stator
1
to
10
θwarn
0
to
95
Warning level
− Setting range
− Steps
0
≤ θwarn
•
1
≤ θwarn
•
10
≤ θwarn
•
<
<
≤
1%
10%
95%
0.001
0.01
0.1
%
%
%
%
Trip time calculation
⎡
⎛ −t ⎞
⎛ −t ⎞ ⎤
⎟ + [1 − p weight ] ⋅ exp⎜
⎟⎥
I2th,stator (t) = I2TrueRMS + [I2th,stator (t = 0) − I2TrueRMS ] ⋅ ⎢pweight ⋅ exp⎜
⎝ τ1,stat ⎠
⎝ τ 2,stat ⎠ ⎥⎦
⎢⎣
θth,stator =
t = t trip
k2stat ⋅ I2flc − I2th,stator
k2stat ⋅ I2flc
for
⋅ 100%
θ th,stator = 0
Ith,stator
ITrue RMS
θth,stator
Iflc
ttrip
Accuracy trip time
C88700-C3527-07-7600
thermal load current stator
largest True RMS phase motor current
thermal reserve stator
full load current
trip time
the higher value of 1 s and
2% of [pweight ⋅ τ1,stat + (1 - pweight) ⋅ τ2,stat]
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.3.3
Technical data
Thermal overload protection of non-rotating objects
Setting ranges / steps
Overload factor
k
Thermal time constant 1
Thermal time constant 2
− Steps for τ1 and τ2
τ1
τ2
•
•
•
1
10
100
≤ tstart
≤ tstart
≤ tstart
<
<
≤
10 s/min/h
100 s/min/h
999 s/min
Weighing factor
pweight
Adjusting factor
cadj
Warning level
− Setting range
− Steps
0
≤ θwarn
•
1
≤ θwarn
•
10
≤ θwarn
•
θwarn
<
<
≤
1%
10%
95%
1
to 1.5
1 s to 999 min
1 s to 999 min
switchable between seconds, minutes
and hours
0.01
s/min/h
0.1
s/min/h
1
s/min
0
to
1
0.01
to
10
0
to
95
0.001
0.01
0.1
%
%
%
%
Trip time calculation
⎡
⎛ −t ⎞
⎛ −t ⎞ ⎤
I2th (t) = I2TrueRMS + [I2th (t = 0) − I2TrueRMS ] ⋅ ⎢pweight ⋅ exp⎜ ⎟ + [1 − pweight ] ⋅ exp⎜ ⎟ ⎥
⎝ τ1 ⎠
⎝ τ 2 ⎠ ⎥⎦
⎢⎣
θth =
k2 ⋅ I2flc − I2th
⋅ 100%
k2 ⋅ I2flc
t = t trip
for
θth = 0
Ith
Itrue RMS
θth
Iflc
ttrip
Accuracy trip time
¡Error! Argumento de modificador desconocido.
thermal load current
largest True RMS phase current
thermal reserve
full load current
trip time
the higher value of 1 s and 2% of [pweight ⋅ τ1 + (1 pweight) ⋅ τ2],
C88700-G1176-U810-3
MFR 7SJ551
3.4
Technical data
Ambient temperature biasing (optional)
Setting ranges / steps
Maximum ambient temperature
Nominal ambient temperature
− Steps for Tmax and Tmin
0
≤T
<
1
•
1
≤T
<
10
•
10
≤T
< 100
•
≤T
≤ 200
• 100
Tmax
Tmin
°C
°C
°C
°C
0
0
0.001
0.01
0.1
1
to 200
to 200
°C
°C
°C
°C
°C
°C
Trip time calculation
I2th,ambient (t) = I2th(t = 0) + cambient
c ambient =
θ th =
Tambient − Tmin 2 2
⋅ k ⋅ Iflc
Tmax − Tmin
k2 ⋅ I2flc − I2th,ambient
k
2
⋅ I2flc
⋅ 100%
t = t trip
for
θth = 0
NOTE:
This trip time calculation applies to rotor
thermal overload protection, stator
thermal overload protection and thermal
overload protection for non-rotating
objects.
C88700-C3527-07-7600
Ith,ambient
Ith
cambient
Tambient
k
Iflc
θth
ttrip
thermal load current adjusted with
ambient temperature
thermal load current
thermal load adjustment with ambient
temperature
measured ambient temperature
overload factor
full load current
thermal reserve
trip time
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.5
Technical data
Start inhibit
Setting ranges / steps
Stator start inhibit level
− Setting range
− Steps
0
≤ θstator <
•
1
≤ θstator <
•
10
≤ θstator ≤
•
θstator
1%
10%
100%
Start inhibit release time
− Setting range
− Steps
•
•
•
•
≤
≤
≤
≤
0
1
10
100
tinh
tinh
tinh
tinh
<
<
<
≤
tinh
1
10
100
166
s/min/h
s/min/h
s/min
s/min
0
0.001
0.01
0.1
to 100
%
%
%
%
0 s to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Calculation rotor start inhibit level
krotor =
τ rotor =
θ rotor =
ncold
ncold − nwarm
− ncold ⋅ tstart
⎛
k2 ⋅ I2flc ⎞
⎟
ln⎜1 − rotor
I2start ⎠
⎝
I2start
k2rotor
⋅ I2flc
⎡
⎛ −t
⎞⎤
⋅ ⎢1 − exp⎜ start ⎟ ⎥ ⋅ 100%
⎝ τ rotor ⎠ ⎥⎦
⎢⎣
¡Error! Argumento de modificador desconocido.
krotor
ncold
nwarm
τrotor
tstart
Iflc
Istart
θrotor
overload factor rotor
permissible number of starts from cold
motor condition
permissible number of starts from warm
motor condition
thermal time constant rotor
permissible start-up time
full load current
permissible start-up current
rotor start inhibit level
C88700-G1176-U810-3
MFR 7SJ551
3.6
Technical data
Locked rotor protection
Setting ranges / steps
Permissible locked rotor time
− Setting range
− Steps
0
≤ tlr
<
1
•
1
≤ tlr
<
10
•
10
≤ tlr
< 100
•
≤ tlr
≤ 200
• 100
tlr
s
s
s
s
0
0.001
0.01
0.1
1
to 200
s
s
s
s
s
Trip time calculation
ttrip
Istart
I
2
t trip
⎛I
⎞
= ⎜ start ⎟ ⋅ t lr
⎝ I ⎠
trip time
permissible start-up current
largest phase motor current
Tolerances
≤ 5
% of setting value
maximum from 10 ms and 2% of tlr
Pick-up value
Delay time
3.7
Zero speed protection
Setting ranges / steps
Zero speed detection time
− Setting range
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
tzero
tzero
tzero
tzero
<
<
<
≤
tzero
1
10
100
166
s/min/h
s/min/h
s/min
s/min
0 s to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Tolerances
Delay time
C88700-C3527-07-7600
maximum from 10 ms and 2% of tzero
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.8
Technical data
Unbalance protection
Setting ranges / steps
Unbalance pick-up
Unbalance time multiplier
− Setting range
− Steps
0
≤ t2p
<
•
1
≤ t2p
<
•
10
≤ t2p
≤
•
I2p/In
0.03
to
1
0
to
25
t2p
0.001
0.01
0.1
1s
10 s
25 s
Bypass time (only for rotating objects)
− Setting range
tbypass
− Steps
0
≤ t2p
<
1s
•
1
≤ t2p
<
10 s
•
10
≤ t2p
< 100 s
•
≤ t2p
≤ 200 s
• 100
0
(steps 0.001)
s
s
s
s
to 100
0.001
0.01
0.1
1
s
s
s
s
s
Trip time calculation
t trip =
80
2
⎛ Iinv ⎞
⎜⎜ ⎟⎟ − 1
⎝ I2p ⎠
ttrip
Iinv
Reset time
⋅ t2p
trip time
inverse component of the phase currents
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of setting value
maximum from 10 ms and 2% of ttrip
Drop off / pick up ratio
Referring to unbalance pick-up value I2p
¡Error! Argumento de modificador desconocido.
0.95 ± 0.01
C88700-G1176-U810-3
MFR 7SJ551
3.9
Technical data
Undercurrent protection
Setting ranges / steps
Undercurrent pick-up
− Setting range
− Steps
• 0.05
≤ I</In
•
1
≤ I</In
•
10
≤ I</In
I</In
<
<
≤
•
•
•
•
0
1
10
100
≤
≤
≤
≤
tI<
tI<
tI<
tI<
t I<
<
<
<
≤
1
10
100
166
to
28
0.001
0.01
0.1
1
10
28
Undercurrent delay time
− Setting range
− Steps
0.05
s/min/h
s/min/h
s/min
s/min
Bypass time (only for rotating objects)
− Setting range
tbypass
− Steps
•
0
≤ tlr
<
1s
•
1
≤ tlr
<
10 s
•
10
≤ tlr
< 100 s
0 s to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
0
to 100
0.001
0.01
0.1
s
s
s
s
Tolerances
Pick-up value
Delay time
≤ 5
% of setting value
maximum from 10 ms and 2% of tI<
Drop off / pick up ratio
Referring to undercurrent pick-up value I<
C88700-C3527-07-7600
1.05 ± 0.01
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.10
Technical data
Overtemperature protection (optional)
Setting ranges / steps
Type setting temperature sensor
Alarm level
− Setting range
− Steps
•
0
≤T
•
1
≤T
•
10
≤T
• 100
≤T
Trip level
− Setting range
− Steps
•
0
≤T
•
1
≤T
•
10
≤T
• 100
≤T
Pt100 or
Ni100 or
Ni120
0
<
<
<
≤
1
10
100
200
°C
°C
°C
°C
1
10
100
200
°C
°C
°C
°C
°C
°C
°C
°C
°C
0.001
0.01
0.1
1
0
<
<
<
≤
to 200
to 200
°C
°C
°C
°C
°C
0.001
0.01
0.1
1
Tolerance
Pick-up value
¡Error! Argumento de modificador desconocido.
≤ 3
°C
C88700-G1176-U810-3
MFR 7SJ551
Technical data
3.11
Low set overcurrent protection
3.11.1
Definite time overcurrent protection
Setting ranges / steps
Phase overcurrent pick-up
− Setting range
− Steps
• 0.05
≤ I>/In
<
•
1
≤ I>/In
<
•
10
≤ I>/In
≤
I>/In
Regular earth overcurrent pick-up
− Setting range
Ie>/In
− Steps
• 0.05
≤ Ie>/In <
1
•
1
≤ Ie>/In <
10
•
10
≤ Ie>/In ≤
28
Sensitive earth overcurrent pick-up
− Setting range
Ie>/In
− Steps
• 0.003
≤ Ie>/In <
1
•
1
≤ Ie>/In < 1.4
t I>
t Ie>
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
t
t
t
t
<
<
<
≤
1
10
100
166
to
28
to
28
0.001
0.01
0.1
1
10
28
Overcurrent delay time
− Setting range
0.05
s/min/h
s/min/h
s/min
s/min
0.05
0.001
0.01
0.1
0.003
to 1.4
0.001
0.01
0s
to 166 min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Pick-up time
approximately 30 ms
Reset time
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of I> or Ie>
maximum from 10 ms and 2% of tI> or tIe>
Drop off / pick up ratio
Referring to overcurrent pick-up value I>
C88700-C3527-07-7600
0.95 ± 0.01
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.11.2
Technical data
Inverse time overcurrent protection
Setting ranges / steps
Phase overcurrent pick-up
− Setting range
− Steps
• 0.05
≤ Ip/In
<
•
1
≤ Ip/In
<
•
10
≤ Ip/In
≤
Ip/In
to
28
to
28
0.001
0.01
0.1
1
10
28
Regular earth overcurrent pick-up
− Setting range
Iep/In
− Steps
• 0.05
≤ Iep>/In <
1
•
1
≤ Iep>/In <
10
•
10
≤ Iep>/In ≤
28
Sensitive earth overcurrent pick-up
− Setting range
Iep/In
− Steps
• 0.025
≤ Iep>/In <
1
•
1
≤ Iep>/In < 1.4
Overcurrent time multiplier
− Setting range
− Steps
•
0
≤ tp
<
•
1
≤ tp
<
0.05
0.05
0.001
0.01
0.1
0.003
0.001
0.01
0
tp
1
10
to 1.4
to
10
0.001
0.01
Trip time calculation
Normally inverse
Very inverse
Extremely inverse
t trip =
t trip =
t trip =
ttrip
I
Ip
tp
¡Error! Argumento de modificador desconocido.
014
.
⎛ I⎞
⎜⎜ ⎟⎟
⎝ Ip ⎠
⋅ tp
0.02
−1
135
.
⋅ tp
I
−1
Ip
80
2
⎛ I⎞
⎜⎜ ⎟⎟ − 1
⎝ Ip ⎠
⋅ tp
trip time
phase or earth current
pick-up current (phase or earth)
time multiplier (phase or earth)
C88700-G1176-U810-3
MFR 7SJ551
Technical data
Additionally for earth current:
Long time earth fault
Residual dependent time
t trip =
⎛ I ⎞
t trip = 5.8 − 135
. ⋅ ln⎜ e ⎟
⎝ Ie > ⎠
ttrip
Ie
Iep
tep
Ie>
Reset time
120
⋅ t ep
Ie
−1
Iep
trip time
earth current
earth current pick-up
earth overcurrent time multiplier
residual dependent time pick-up
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of setting value
maximum from 10 ms and 2% of ttrip
Drop off / pick up ratio
Referring to phase overcurrent pick-up value Ip or
earth overcurrent pick-up value Iep
C88700-C3527-07-7600
0.95 ± 0.01
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.11.3
Technical data
Custom curve overcurrent protection
Setting ranges / steps
Number of points
2 - 15
Phase overcurrent pick-up
− Setting range
− Steps
≤ I1/In
<
• 0.05
1
≤ I1/In
<
•
•
10
≤ I1/In
≤
I1/In
Regular earth overcurrent pick-up
Ie1>/In
− Setting range
− Steps
≤ Ie1>/In <
1
• 0.05
•
1
≤ Ie1>/In <
10
10
≤ Ie1>/In ≤
28
•
Sensitive earth overcurrent pick-up
Ie1>/In
− Setting range
− Steps
≤ Ie1>/In <
1
• 0.05
1
≤ Ie1>/In <
10
•
10
≤ Ie1>/In ≤
28
•
•
•
•
•
0
1
10
100
≤
≤
≤
≤
t
t
t
t
<
<
<
≤
tI1 ... tI15
1
10
100
166
to
28
to
28
0.001
0.01
0.1
1
10
28
Custom curve time points
− Setting range
− Steps
0.05
(I1 ... I15)
s/min/h
s/min/h
s/min
s/min
Reset time
0.05
0.001
0.01
0.1
0.0025
to 1.4
0.001
0.01
0.1
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of setting value
maximum from 10 ms and 2% of ttrip
Drop off / pick up ratio
Referring to phase overcurrent pick-up value I1 or
earth overcurrent pick-up value Ie1
¡Error! Argumento de modificador desconocido.
0.95 ± 0.01
C88700-G1176-U810-3
MFR 7SJ551
3.12
Technical data
High set overcurrent protection
Setting ranges / steps
Phase overcurrent pick-up
− Setting range
− Steps
≤ I>>/In <
• 0.05
1
≤ I>>/In <
•
10
≤ I>>/In ≤
•
I>>/In
Regular earth overcurrent pick-up
Ie>>/In
− Setting range
− Steps
• 0.05
≤ Ie>>/In <
1
1
≤ Ie>>/In <
10
•
10
≤ Ie>>/In ≤
28
•
Sensitive earth overcurrent pick-up
Ie>>/In
− Setting range
− Steps
≤ Ie>>/In <
1
• 0.025
1
≤ Ie>>/In < 1.4
•
t I>>
t Ie>>
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
t
t
t
t
<
<
<
≤
1
10
100
166
to
28
to
28
0.001
0.01
0.1
1
10
28
Overcurrent delay time
− Setting range
0.05
s/min/h
s/min/h
s/min
s/min
0.05
0.001
0.01
0.1
0.0025
to 1.4
0.001
0.01
0s
to 166 min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Pick-up time
approximately 30 ms
Reset time
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of I>> or Ie>>
maximum from 10 ms and 2% of tI>> or tIe>>
Drop off / pick up ratio
Referring to high set overcurrent pick-up value I>>
C88700-C3527-07-7600
0.95 ± 0.01
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.13
Technical data
Curve switch
Setting ranges / steps
Curve switch mode
continuous or
pulse or
motor status related (only for rotating objects)
Motor status (only for rotating objects)
start/stop or
running
Curve switch activation time
− Setting range
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
tCS
tCS
tCS
tCS
<
<
<
≤
1
10
100
166
tCS
s/min/h
s/min/h
s/min
s/min
¡Error! Argumento de modificador desconocido.
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
C88700-G1176-U810-3
MFR 7SJ551
3.14
Technical data
Directional earth fault protection (optional)
Displacement voltage detection
Displacement voltage
− Setting range
− Steps
≤ Ustrt/Un <
• 0.05
1
≤ Ustrt/Un <
•
Ustrt/Un
0
1
10
100
≤
≤
≤
≤
tUstrt
tUstrt
tUstrt
tUstrt
tUstrt
<
<
<
≤
1
10
100
166
to 1.2
0.001
0.01
1
1.2
Pick-up delay
− Setting range
− Steps
•
•
•
•
0.05
s/min/h
s/min/h
s/min
s/min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
0.95 ± 0.01
Drop-off ratio
Measurement tolerance
5% of set value
Time tolerance
maximum from 10 ms and 2% of tUstrt
Sensitive earth current detection
High set earth current pick-up
Iφ>>/In
− Setting range
− Steps
≤ Iφ>>/In <
1
• 0.025
1
≤ Iφ>>/In < 1.4
•
Delay time
− Setting range
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
t Iφ>>
t
t
t
t
Iφ>>
Iφ>>
Iφ>>
Iφ>>
<
<
<
≤
1
10
100
166
s/min/h
s/min/h
s/min
s/min
Low set earth current pick-up (definite time)
− Setting range
Iφ>/In
− Steps
≤ Iφ>/In <
1
• 0.025
1
≤ Iφ>/In < 1.4
•
Delay time
− Setting range
− Steps
•
•
•
0
1
10
≤ t Iφ>
≤ t Iφ>
≤ t Iφ>
t Iφ>
<
<
<
C88700-C3527-07-7600
1 s/min/h
10 s/min/h
100 s/min
0.0025
to 1.4
0.001
0.01
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
0.0025
to 1.4
0.001
0.01
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
•
100
≤ t Iφ>
Technical data
≤
166 s/min
Low set earth current pick-up (definite time)
Iφp/In
− Setting range
− Steps
≤ Iφp/In <
1
• 0.025
1
≤ Iφp/In < 1.4
•
Time multiplier
− Setting range
− Steps
0
≤ tφp
•
1
≤ tφp
•
tφp
<
<
1s
10 s
Characteristics
1
s/min
0.0025
to 1.4
0.001
0.01
0
to
0.001
0.01
10
s
s
s
normally inverse
very inverse
extremely inverse
long time earth fault
residual dependent time
custom curve
Measuring tolerance
5% of setting value
Time tolerance
maximum from 10 ms and 2% of time setting value
Drop-off ratio
0.95 ± 0.01
Directional determination
Measurement
with Ie and U0
Measuring principle
active power (cos φ measurement) or
reactive power (sin φ measurement)
Directional trip condition
forward or
backward
Rotation angle
φe
− Setting range
− Steps
0
≤ φe
<
1
•
1
≤ φe
<
10
•
•
10
≤ φe
≤
45
(negative range similar)
CT angle correction
Ie ≤ 100 mA
−
− 100 mA < Ie ≤ 200 mA
Ie > 200 mA
−
− Steps
0°
≤δ
<
•
1°
≤δ
<
•
-45°
to +45°
0.001°
0.01°
0.1°
δ1
δ2
δ3
1°
5°
¡Error! Argumento de modificador desconocido.
0°
0°
0°
to
to
to
5°
5°
5°
0.001°
0.01°
C88700-G1176-U810-3
MFR 7SJ551
3.15
Technical data
Undervoltage protection (optional)
Setting ranges / steps
Undervoltage pick-up
− Setting range
− Steps
≤ U</Un <
• 0.05
1
≤ U</Un <
•
U</Un
•
•
•
•
0
1
10
100
≤
≤
≤
≤
tU<
tU<
tU<
tU<
t U<
<
<
<
≤
1
10
100
166
to 1.2
0.001
0.01
1
1.2
Undervoltage delay time
− Setting range
− Steps
0.05
s/min/h
s/min/h
s/min
s/min
0 s to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Pick-up time
approximately 30 ms
Reset time
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of setting value
maximum from 10 ms and 2% of tU<
Drop off / pick up ratio
Referring to undervoltage pick-up value U<
C88700-C3527-07-7600
1.05 ± 0.01
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.16
Technical data
Overvoltage protection (optional)
Setting ranges / steps
Overvoltage pick-up
− Setting range
− Steps
≤ U/Un <
• 0.05
1
≤ U/Un <
•
(U = U> or U>>)
U>/Un
U>>/Un
t U>
t U>>
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
t
t
t
t
<
<
<
≤
1
10
100
166
to 1.2
to 1.2
0.001
0.01
1
1.2
Overvoltage delay time
− Setting range
0.05
0.05
s/min/h
s/min/h
s/min
s/min
0s
to 166 min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Pick-up time
approximately 30 ms
Reset time
approximately 40 ms
Tolerances
Pick-up value
Delay time
≤ 5
% of U> or U>>
maximum from 10 ms and 2% of tU> or tU>>
Drop off / pick up ratio
Referring to overvoltage pick-up values U> or U>>
¡Error! Argumento de modificador desconocido.
0.95 ± 0.01
C88700-G1176-U810-3
MFR 7SJ551
3.17
Technical data
Breaker failure protection
Setting ranges / steps
Pick-up value of current stage
Ibf/In
− Setting range
− Steps
0
≤ Ibf/In
<
1
•
1
≤ Ibf/In
<
10
•
10
≤ Ibf/In
≤
28
•
Time stage
− Setting range
− Steps
•
•
•
•
0
1
10
100
3.18
≤
≤
≤
≤
t Ibf
t
t
t
t
<
<
<
≤
1
10
100
166
s/min/h
s/min/h
s/min
s/min
0
to
28
0.001
0.01
0.1
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Block
Setting ranges / steps
Block mode
continuous or
pulse or
motor status related (only for rotating objects)
Motor status (only for rotating objects)
start/stop or
running
Block activation time
− Setting range
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
tBLOCK
tBLOCK
tBLOCK
tBLOCK
tBLOCK
<
<
<
≤
Blockable functions
C88700-C3527-07-7600
1
10
100
166
s/min/h
s/min/h
s/min
s/min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
low set overcurrent
high set overcurrent
undercurrent
undervoltage
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
3.19
Technical data
External command
Setting ranges / steps
Delay time
− Setting range
− Steps
•
•
•
•
≤
≤
≤
≤
0
1
10
100
text
text
text
text
text
<
<
<
≤
1
10
100
166
s/min/h
s/min/h
s/min
s/min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Tolerances
Delay time
3.20
maximum from 10 ms and 2% of text
Ancillary functions
Operational value measurements
Operational current values
− range
IL1, IL2, IL3, Ie
0 to 28 · In
Operational voltage values (optional)
− range
Uln or Uph or U0
0 to 1.2 · Un
Directional earth current value (optional)
− range
Iφ
0 to 1.4 · In
Thermal reserve values
− range
θth, θth,rotor or θth,stator
0 to 100% (or even higher in combination with
ambient temperature biasing)
Inverse component of the phase currents
− range
I2
0 to 1 · In
Operational temperature values (optional)
− range
T1 ... T8
0 to 200°C
Motor status
stopped or
start or
running
Circuit breaker statistical data
Number of stored alarm or trip events
Last interrupted current
Total of tripped currents
¡Error! Argumento de modificador desconocido.
C88700-G1176-U810-3
MFR 7SJ551
Technical data
Fault event data storage
Storage of annunciations of the last three faults
Reset
Automatic reset time (latched output relays)
treset
− Setting range
− Steps
•
•
•
•
0
1
10
100
≤
≤
≤
≤
treset
treset
treset
treset
<
<
<
≤
1
10
100
166
s/min/h
s/min/h
s/min
s/min
0s
to 166 min
switchable between seconds, minutes
and hours
0.001
s/min/h
0.01
s/min/h
0.1
s/min
1
s/min
Demand amperemeter
8 minutes average
15 minutes average
maximum 8 minutes average
maximum 15 minutes average
Running hours counter
actual running hours (since previous start-up)
total running hours
General data
ordering code
serial number
software version
Data storage for fault recording (optional)
Activation criterion
alarm or
trip
Total recording time
3s
Sampling rate
− 50 Hz
− 60 Hz
600 s-1
720 s-1
Real time clock
Clock module
C88700-C3527-07-7600
DALLAS type DS 1286
self-discharge time approximately 10 years
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
4
Method of operation
4.1
Operation of the complete unit
The multi-function protection relay MFR 7SJ551
is equipped with a powerful and proven
microcontroller. This provides fully digital
processing of all functions from data acquisition
of measured values to the tripping of the circuit
breaker.
Fig. 4.1 shows the basic structure of the unit.
The measured currents are fed to the relay via
the input transducers for each phase. The
inputs are galvanically isolated against the
electronic circuits as well as against each other.
For the earth current input either the residual
current of the phase current transformers or a
separate summation current transformer can be
connected.
Figure 4.1
Method of operation
The measured voltage is fed to the voltage input
transducer. This can be a phase to phase
voltage, a phase to earth voltage or a zero
sequence (open triangle) voltage.
The measured value inputs ME transform the
currents and voltage from the measurement
transformers and match them to the internal
processing level of the unit. Apart from the
galvanic and low-capacitive isolation provided
by the input transformers, filters are provided
for the suppression of interference. The filters
have been optimized with regard to bandwidth
and processing speed to suit the measured
value processing. The matched analogue values
are then passed to the analogue input section
AE.
Hardware structure of multi-function protection relay MFR 7SJ551
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
The analogue input section AE contains input
amplifiers, sample and hold elements for each
input, analogue-to-digital converters and
memory circuits for the data transfer to the
microprocessor.
signals). Outputs include, in particular, trip
commands to the circuit breaker, signals for
remote signalling of important events and
conditions as well as visual displays (LED's) and
an alpha-numerical display on the front.
Apart from control and supervision of the
measured values, the microprocessor processes
the actual protective functions. These include in
particular:
An integrated keyboard in connection with a
built-in alpha-numerical LCD display enables
communication with the unit. All operational
data such as setting values, component data,
etc., are entered into the protection relay from
this panel (refer to sections 6.3 to 6.12). Using
this panel the parameters can be recalled and
the relevant data for the evaluation of a fault
can be read out after a fault has occurred (refer
to section 6.14). The dialogue with the relay
can be carried out alternatively via the serial
interface (optional) by means of a personal
computer or a central evaluation unit. During
healthy operation, measured values can be
transmitted, e.g. of load currents. Both
interfaces are isolated; isolation and interference
suppression comply with the requirements
according to VDE 0435, part 303 and IEC 255.
− filtering and formation of the measured
quantities,
− continuous calculation of the values which
are relevant for fault detection,
− determination of the faulted phases in case
of a fault,
− calculation of True RMS values and
symmetric component values for overload
detection,
− calculation of the directional earth fault data,
− scanning of limit values and time sequences,
− decision about trip command activations,
− storage of measured quantities during a fault
for analysis.
Binary inputs and outputs to and from the
processor are channelled via the input/output
elements. From these the processor receives
information from other equipment (e.g. blocking
4.2
Thermal overload protection
4.2.1
Theoretical background
MFR 7SJ551 uses thermal memories to
resemble the remaining thermal capacity of the
protected component. The remaining thermal
capacity can be calculated out of the measured
currents.
For overload protection MFR 7SJ551
distinguishes between rotating devices (motors)
and non-rotating devices (transformers, blowout coils or cables). Furthermore, for motors
MFR 7SJ551 uses different thermal models for
the rotor (single-body model) and the stator
G88700-C3527-07-7600
A power supply unit provides the auxiliary
supply on the various voltage levels to the
described functional units. + 24 V is used for
the relay outputs. The analogue input requires
± 15 V whereas the processor and its
immediate peripherals are supplied with + 5 V.
Transient failures in the supply voltage, up to
500 ms, which may occur during short-circuits
in the supply system of the plant are bridged by
a voltage storage element (refer to section
3.1.1).
(two-body model). For non-rotating devices the
same two-body model is used.
Both the single-body and the two-body thermal
models are derived from thermal physics in the
following manner.
4.2.1.1
Single-body thermal overload model
A current flowing through a conductor will
cause electric losses proportional to the square
value of the current (refer to figure 4.2):
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
Pe = f ⋅ i2
t
T(t) − Tambient
with Pe
− electric warmth dissipation
generated by the electric current I
f
− proportional factor
i
− electric current
+
1
⋅ Pe
A⋅α
with τ
Pheating
i
T0
Ploss
Pe
Tmaz =
Tambient
Electric losses in a single
conducting body
The electrical losses Pe will cause temperature
rising of the body and the body itself will radiate
warmth into the surrounding environment:
Pe = Pheating + Ploss
loss
with Pheating − thermal losses absorbed by the
body
Ploss
− thermal losses radiated into the
environment
with Tmax
dT
dt
Ploss = A ⋅ α ⋅ (T − Tambient )
with m
C
T
A
α
Tambient
−
−
−
−
−
−
mass
specific warmth capacity
temperature
area
thermal transfer factor
ambient temperature
1
⋅ Pe + Tambient
A⋅α
− maximum temperature for
current i
We assume the current is a step function:
i(t) = I0 for t < 0
i(t) = I for t > 0
Then, with Pe = f ⋅ i2 we get:
Tmax =
f
⋅ I2 + Tambient
A⋅α
and:
From thermal physics the following relations
apply:
Pheating = m ⋅ C ⋅
− warming-up time constant,
m⋅C
τ=
A⋅α
− temperature at t = 0
As soon as Ploss equals Pe the body has reached
its maximum temperature (t ⌫ ∞):
T
Figure 4.2
1
⎛
⎞ −
= ⎜ T0 − Tambient −
⋅ Pe ⎟ ⋅ e τ +
⎝
⎠
A⋅α
T0 =
with I0
f
⋅ I20 + Tambient
A⋅α
− preload current
Figure 4.3 shows the step response of the
temperature of the body.
When we fill in these relations expression for Pe
we get:
m⋅C⋅
dT(t)
+ A ⋅ α ⋅ (T − Tambient ) = Pe
dt
This is a first order differential equation in T
with the following solution:
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Tmax
Method of operation
Filling in the basic equation for the thermal
model gives:
T
I2th (t trip )
T0
=
k2I2flc
=
(I20
2
−I )⋅e
−
t trip
τ
+ I2
⎛ I2 − I20 ⎞
⎟
t trip = τ ⋅ ln⎜ 2
2 2
⎝ I − k ⋅ Iflc ⎠
⇒
Figure 4.4 illustrates the above equations.
Tambient
Figure 4.3
t
t=0
Tmax
Current step response of the
temperature
The solution of the differential equation changes
to:
f
⎛ f
⎞
T(t) − Tambient = ⎜
⋅ I2 −
⋅ I2 ⎟ ⋅ e
⎝A⋅α 0 A⋅α
⎠
−
t
τ
with Ith
+
f
⋅ I2
A⋅α
f
=
⋅ I2th(t)
A⋅α
− thermal current
This leads to the basic equation for the 3parameter thermal model:
I2th(t)
=
(
I20
2
−I
)⋅e
−
t
τ
Ttrip
T0-2
T0-1
Now a calculation quantity is introduced: the
‘thermal current’ Ith.
T(t) − Tambient
T
Tambient
ttrip-2
Figure 4.4
t
ttrip-1
Warming up to trip temperature
Figure 4.5 shows the relation between the trip
time and the temperature for different preload
currents.
ttrip
+ I2
For electric network components the maximum
allowable current is:
Imax = k · Iflc
with Imax
k
Iflc
− maximum allowable current
− safety factor
− full load current
When the current exceeds k · Iflc the
temperature will rise to the maximum allowable
temperature Ttrip. At this time point MFR
7SJ551 will trip the electric component. In the
model this is represented by:
Ith = k · Iflc
G88700-C3527-07-7600
k·Iflc
I
Iflc
Figure 4.5
Thermal limit curve
Another way of expressing the trip condition is
by using the remaining thermal capacity θth:
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
θ th(t) =
with θth
Method of operation
k2 ⋅ I2flc − I2th(t)
⋅ 100%
k2 ⋅ I2flc
− thermal reserve
The 5-parameter model can be derived in the
same manner as the 3-parameter model and
results in the following electric analogon (refer
to figure 4.7):
1
A2 ⋅ α 2
For T = Ttrip the thermal reserve is 0%:
θ th(t trip ) =
k2 ⋅ I2flc − I2th(t trip )
k2 ⋅ I2flc
T(t)
⋅ 100% = 0%
With this we have completed the single-body
model. It is built with the three parameters Iflc, k
and τ.
The single-body model can be represented by an
electric analogon (refer to figure 4.6):
m1·C1
Pe
m2·C2
1
A2 ⋅ α 2
Tambient
Figure 4.7
T(t)
Electric analogon for two-body
model
The following solution for T(t) is achieved:
Pe
m·C
1
A⋅α
⎛
⎞
1
1
T(t) − Tamb = ⎜ T0 − Tamb − (
+
) ⋅ Pe ⎟ ⋅
A1 ⋅ α1 A2 ⋅ α2
⎝
⎠
Tambient
Figure 4.6
4.2.1.2
Electric analagon for single-body
model
t
⎛ −t
− ⎞
1
1
⋅⎜ pe τ1 + (1 − p) ⋅ e τ2 ⎟ + (
) ⋅ Pe
+
⎜
⎟
A1 ⋅ α1 A2 ⋅ α2
⎝
⎠
with Tamb
τ1
Two-body thermal overload model
The single-body model is reasonably accurate
for homogenous bodies. When bodies consist of
different materials, like copper and iron the
single-body can be insufficient. MFR 7SJ551
therefore provides the possibility to simulate the
thermal behaviour of an electric network
component more accurately with a two-body
model. This makes it possible to utilize the
network component to the full because the
overload protection can be set more critical,
avoiding premature tripping.
From:
Pheating = m ⋅ C ⋅
dT
dt
we can see that for a body with two different
materials with thermal warming-up capacities C1
and C2 a differential equation for T consisting of
two differential parts is applicable.
¡Error! Argumento de modificador desconocido.
− ambient temperature
− warming-up time constant of
m ⋅C
material 1, τ1 = 1 1
A1 ⋅ α1
τ2
− warming-up time constant of
m ⋅C
material 2, τ2 = 2 2
A2 ⋅ α2
p
− weighing factor representing
the mutual warming-up
influence of the two materials
of the body
In analogy with the derivation of the thermal
current of the 3-parameter model we obtain the
basic equation for the 5-parameter thermal
model:
t
t
⎛
−
− ⎞
I2th (t) = (I20 − I2 ) ⋅ ⎜ p ⋅ e τ1 + (1 − p) ⋅ e τ2 ⎟ + I2
⎜
⎟
⎝
⎠
For T = Ttrip the remaining thermal reserve is
0%
Ith = k · Iflc
G88700-C3527-07-7600
MFR 7SJ551
Method of operation
or:
θ th(t trip ) =
4.2.2
k2 ⋅ I2flc − I2th(t trip )
k2 ⋅ I2flc
⋅ 100% = 0%
With this we have completed the two-body
model. It is built with the five parameters Iflc, k,
τ1, τ2 and p.
Rotor thermal overload protection
The rotor thermal overload protection is
available when the user chooses the rotating
device parameter set. Although the two thermal
overload functions work at the same time, the
rotor thermal overload protection protects the
rotor completely independent from the stator
thermal overload protection. It uses a separate
thermal memory, represented during operation
by the separate display quantity ‘rotor thermal
reserve’. The rotor thermal overload protection
primarily acts on higher currents during start,
during which the rotor thermal reserve
decreases. When the motor has passed a
successful start and is running at full load
current the rotor thermal reserve will increase
again according to the changes of the nominal
temperature.
When putting the operating condition from MFR
7SJ551 from ‘off line’ to ‘on line’ the thermal
memory is initiated at 0%.
MFR 7SJ551 computes the temperature rise of
the rotor according to the single-body model.
The rotor safety factor and the rotor warmingup time constant are computed indirectly out of
the motor manufacturer data. Under assumption
that the start-up time is much smaller than the
rotor warming-up time constant the following
formulas can be derived:
k2rotor =
τ rotor =
with krotor
ncold
nwarm
ncold
ncold − nwarm
− ncold ⋅ tstart
⎛
k2 ⋅ I2flc ⎞
⎟
ln⎜1 − rotor
I2start ⎠
⎝
− rotor safety factor
− permissible number of starts
from cold condition
− permissible number of starts
from warm condition
G88700-C3527-07-7600
τrotor
tstart
Iflc
Istart
− (fictive) rotor warming-up time
constant
− start-up time at nominal voltage
− full load current
− start-up current at nominal
voltage
These relations for the rotor safety factor and
the rotor warming-up time constant express the
influence of the slip on the rotor warming-up
during start.
In the rotor model the equivalent heating current
is introduced. This current can be calculated
according to the following formula:
I2heating = I2norm + kinv ⋅ I2inv
with Iheating
Inorm
kinv
Iinv
− equivalent heating current
− normal component of the three
phase currents
− inverse factor representing the
extra warming up due to
asymmetric currents
− inverse component of the three
phase currents
The calculation of Inorm and Iinv depends on how
many current phases are connected. For threephase connection Inorm and Iinv are calculated
with the symmetric components method. As
direction of the vectors either ‘clockwise’ or
‘counterclockwise’ can be externally selected by
means of a binary input. When the direction is
reversed, the calculation of the inverse current
and the calculation of the normal current are
reversed, too.
For two-phase connection the following
formulas are applicable:
Inorm = Imax
Iinv = Imax − Imin
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
− the largest of the two phase
currents
− the smallest of the two phase
currents
with Imax
Imin
The rotor thermal model basic iterative equation
becomes (motor status ‘start’ or ‘running’):
I2th,rotor (t)
=
(
I2th,rotor( t
with Ith,rotor
= 0) −
I2heating
)⋅e
−
t
τ rotor
+ I2heating
k2rotor ⋅ I2flc − I2th,rotor(t trip )
k2rotor ⋅ I2flc
⋅ 100% = 0%
with θth,rotor − rotor thermal reserve
For currents higher than krotor · Iflc the rotor
thermal reserve will decrease to 0%.
Theoretically, with this rotor thermal model
formed with Istart, tstart, ncold and nwarm we achieve
that we can start and stop the motor exactly
ncold times from cold motor condition with a
(constant) starting current Istart , when we let
each start last exactly tstart, without pausing
between the starts. Than the thermal reserve
will be exactly 0%.
4.2.3
When the motor status is ‘stopped’ the basic
iterative equation changes to:
− thermal rotor current
MFR 7SJ551 calculates the thermal rotor
current periodically and compares it with krotor ·
Iflc. When these quantities are equal, the tripping
condition is fulfilled:
θ th,rotor(t trip ) =
From the formula for τrotor it follows that MFR
7SJ551 allows a motor to be started from cold
condition more often than ncold. For example,
when the starting time is halved for each start,
or when the starting current is halved, the
motor may be started 2 ncold from cold
condition! The same accounts for starts from
warm condition.
I2th,rotor ( t)
=
(
I2th,rotor ( t
= 0) −
I2heating
)⋅e
−
t
c stop , rot ⋅τ rotor
+ I2heating
with cstop,rot − rotor cooling down factor
Cooling down the rotor to the original
temperature after switching if off takes cstop,rot
times longer than warming it up to the original
temperature.
As soon as the thermal reserve reaches 0% the
rotor thermal overload protection will step into
the TRIP condition. The TRIP LED and the
output relay TRIP θth will be energized.
When the auxiliary voltage drops out during on
line operating condition and is switched on after
a certain amount of time, the contents of the
thermal memory is calculated using the real time
clock as if the motor had stopped during this
time, i.e. as if Iheating was zero.
Stator thermal overload protection
The stator thermal overload protection is
available when the user chooses the rotating
device parameter set. Although the two thermal
overload functions work at the same time, the
stator thermal overload protection protects the
stator completely independent from the rotor
thermal overload protection. It works with a
separate thermal memory, represented during
operation by the separate display quantity
‘stator thermal reserve’. The stator thermal
overload protection primarily acts on relatively
low overcurrents when the motor is running.
When the motor passes a successful start and
¡Error! Argumento de modificador desconocido.
is running at full load current the stator thermal
reserve will decrease to an equilibrium level.
When putting the operating condition from the
MFR 7SJ551 from ‘off line’ to ‘on line’ the
thermal memory is initiated at 0%.
MFR 7SJ551 computes the temperature rise of
the stator according to the two-body model,
using as measuring input the highest true root
mean square value of the phase currents.
G88700-C3527-07-7600
MFR 7SJ551
Method of operation
The stator thermal model basic iterative
equation becomes (motor status ‘start’ or
‘running’):
I2th,stat (t) = (I2th,stat (t = 0) − I2 ) ⋅
I2th,stat (t) = (I2th,stat (t = 0) − I2 ) ⋅
t
t ⎞
⎛
−
−
τ1,stat
τ2,stat ⎟
⎜
2
⋅⎜ pweight ⋅ e
+ (1 − pweight ) ⋅ e
⎟ +I
⎝
⎠
with Ith,stat
I
pweight
τ1,stat
τ2,stat
− thermal stator current
− highest true root mean square
value of the phase currents
− weighing factor
− stator warming-up time
constant 1
− stator warming-up time
constant 2
MFR 7SJ551 calculates the thermal stator
current periodically and compares it with kstat ·
Iflc. When these quantities are equal, the tripping
condition is fulfilled:
θth,stat (t trip ) =
with θth,stat
kstat
Iflc
k2stat
⋅ I2flc − I2th,stat (t trip )
k2stat ⋅ I2flc
⋅ 100% = 0%
− stator thermal reserve
− stator safety factor
− full load current
For currents higher than kstat · Iflc the stator
thermal reserve will decrease to 0%.
4.2.4
When the motor status is ‘stopped’ the basic
iterative equation changes to:
t
t
⎛
⎞
−
−
c stop,stat τ1,stat
c stop,stat τ 2,stat ⎟
⎜
2
⋅⎜ pweight ⋅ e
+ (1 − pweight ) ⋅ e
⎟ +I
⎝
⎠
with cstop,stat − stator cooling down factor
Cooling down the stator to the original
temperature after switching if off takes cstop,stat
times longer than warming it up to the original
temperature.
When the stator thermal reserve decreases
under the warning level θwarn, the stator thermal
overload protection will step into the ALARM
condition. The LED’s PRE-ALARM and ALARM
and the output relay PRE-ALARM will
annunciate this condition. This makes it possible
to reduce load in an early stage.
As soon as the thermal reserve reaches 0% the
stator thermal overload protection will step into
the TRIP condition. The TRIP LED and the
output relay TRIP θth will be energized.
When the supply voltage drops out during on
line operating condition and is switched on after
a certain amount of time, the contents of the
thermal memory is calculated using the real time
clock as if the motor had stopped during this
time, i.e. as if Irms was zero.
Thermal overload protection of transformers, blow-out coils and cables
When the user chooses the non-rotating device
parameter set one thermal overload protection
function is available. It works with a thermal
memory, represented during operation by the
display quantity ‘thermal reserve’. The thermal
overload protection is meant primarily for
protection against relatively low overcurrrents
when the electric network component is loaded
to a maximum. When the network component is
operated at full load current the stator thermal
reserve will decrease to an equilibrium level.
When putting the operating condition of the
MFR 7SJ551 from ‘off line’ to ‘on line’ the
thermal memory is initiated at 0%.
MFR 7SJ551 computes the temperature rise of
the network component according to the fiveparameter model, using as measuring input the
highest true root mean square value of the
phase currents.
The thermal model basic iterative equation
becomes:
I2th (t) = (I2th (t = 0) − I2 ) ⋅
t
t
⎛
−
− ⎞
⋅⎜ pweight ⋅ e τ1 + (1 − pweight ) ⋅ e τ2 ⎟ + I2
⎜
⎟
⎠
⎝
with Ith
G88700-C3527-07-7600
− thermal current
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MFR 7SJ551
I
pweight
τ1
τ2
Method of operation
− highest true root mean square
value of the phase currents
− weighing factor
− warming-up time constant 1
− warming-up time constant 2
MFR 7SJ551 calculates the thermal current
periodically and compares it with k · Iflc. When
these quantities are equal, the tripping condition
is fulfilled:
2
θ th(t trip ) =
with θth
k
Iflc
k
⋅ I2flc − I2th(t trip )
k2 ⋅ I2flc
⋅ 100% = 0%
− thermal reserve
− safety factor
− full load current
For currents higher than k · Iflc the thermal
reserve will decrease to 0%.
When the binary input ‘τ adjust’ is energized,
the basic iterative equation changes to:
(
)
I2th (t) = I2th (t = 0) − I2 ⋅
t
t
⎛
⎞
−
−
c ⋅τ
c ⋅τ
⋅⎜ pweight ⋅ e adj 1 + (1 − pweight ) ⋅ e adj 2 ⎟ + I2
⎜
⎟
⎝
⎠
4.3
with cadj
− adjustment factor for warmingup time constants
For a constant input current this means that the
time it takes to warm up is cadj times larger than
for inactive binary input ‘τ adjust’. This can be
used for example for network components with
forced cooling. When the cooling is switched on
larger warming-up time constants are needed.
When the thermal reserve decreases under the
warning level θwarn, the thermal overload
protection will step into the ALARM condition.
The LED’s PRE-ALARM and ALARM and the
output relay PRE-ALARM will annunciate this
condition. This makes it possible to reduce load
in an early stage.
As soon as the thermal reserve reaches 0% the
thermal overload protection will step into the
TRIP condition. The TRIP LED and the output
relay TRIP θth will be energized.
When the supply voltage drops out during on
line operating condition and is switched on after
a certain amount of time, the contents of the
thermal memory is calculated using the real time
clock as if the network component was
unloaded during this time, i.e. as if I was zero.
Ambient temperature biasing (optional)
With the function ambient temperature biasing
the thermal reserve can be adjusted according
to the actual ambient temperature. Therefore a
sensor measuring the ambient temperature is
necessary. The sensor is connected to one of
the temperature sensor inputs of the (optional)
interface unit.
figure 4.8): for nominal ambient temperature
Tmin the thermal reserve is 100%. When the
ambient temperature increases to a maximum
allowable level Tmax the thermal reserve of the
network component decreases to 0%. When
the ambient temperature decreases below
nominal ambient temperature Tmin the thermal
reserve will be larger than 100%.
We consider a cold network component, i.e. the
preload is 0%, without load current (refer to
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G88700-C3527-07-7600
MFR 7SJ551
Method of operation
θth, ambient
c ambient =
with Ith,ambient − thermal load current adjusted
with ambient temperature
− thermal load current
Ith
cambient − thermal load adjustment to
ambient temperature
Tambient − measured ambient temperature
k
− overload factor
Iflc
− full load current
100%
0%
Tmin
Figure 4.8
Tmax
Tambient
Offset in cold condition
For a warm network component under load
condition the temperature rise caused by
electrical heating and the ambient temperature
rise are added.
Ambient temperature biasing causes the thermal
current to increase with an amount proportional
to the ambient temperature rise:
I2th,ambient (t) = I2th(t = 0) + cambient
4.4
Tambient − Tmin 2 2
⋅ k ⋅ Iflc
Tmax − Tmin
MFR 7SJ551 calculates the thermal load current
periodically and compares it with k · Iflc. When
these quantities are equal, the tripping condition
is fulfilled:
θth =
with θth
ttrip
k2 ⋅ I2flc − I2th,ambient
k2 ⋅ I2flc
⋅ 100% = 0%
− thermal reserve
− trip time
This trip time calculation applies to thermal
overload protection for non-rotating objects as
well as rotor thermal overload protection and
stator thermal overload protection.
Start inhibit
After the thermal overload protection has
tripped, the motor has to cool off before it can
be put in operation again. The start inhibit
function can be used to prevent the motor from
being started until it has regained sufficient
thermal reserve. For that purpose MFR 7SJ551
energizes a start inhibit output relay that must
be used to prevent the circuit breaker from
being closed. As long as the motor is to warm
to complete a start this signal will make it
impossible to start it. (Only the emergency
restart function makes it possible to override
this signal.)
G88700-C3527-07-7600
temperature
Ttrip
Tinhibit
trip
Figure 4.9
start release
t
Start inhibit principle
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MFR 7SJ551
Method of operation
For the rotor thermal overload model a new
start of the motor is blocked until the thermal
reserve has increased to the rotor start inhibit
level θrotor:
t
⎛
⎞
−
I2start
τ
⎜
⎟ ⋅ 100%
e
θrotor = 2
⋅
1
−
⎟
krotor ⋅ I2flc ⎜⎝
⎠
start
rotor
with θrotor
Istart
krotor
Iflc
tstart
τrotor
−
−
−
−
−
−
rotor start inhibit level
permissible start-up current
overload factor rotor
full load current
permissible start-up time
thermal time constant rotor
For the stator thermal overload model a new
start of the motor is blocked until the thermal
4.5
The time until the start inhibit output is released
can be extended with the start inhibit release
time tinh. The two thermal models (rotor and
stator) serve both at the same time as input for
determining whether a start can be released.
Apart from that an additional delay time can be
set.
When the motor is stopped (automatically or
manually) and at that moment the remaining
rotor or stator thermal capacities are smaller
than the respective rotor or stator inhibit levels
a new start of the motor is blocked.
Emergency restart
The emergency restart function can only be
activated in combination with the start inhibit
function. The emergency restart function makes
it possible to override the start inhibit blocking
signal by energizing the emergency restart
binary input. By energizing this binary input the
thermal rotor reserve and the thermal stator
reserve are set back to 100%, thus releasing
the start inhibit output.
This means that a new start is released in spite
of the possible danger of reaching a too high
temperature of the motor! The function is only
4.6
reserve has increased to the settable stator start
inhibit level θstator.
meant for use in situations where the motor is
less important than the process it is driving.
The user only has to activate the function
emergency restart, no parameters need to be
set.
The emergency restart order will be executed
when the emergency restart binary input is
energized while the motor status is ‘stopped’
and the thermal reserve is smaller than the start
inhibit level. Together with the start inhibit
output the LED ‘start inhibit’ will be
deactivated.
Locked rotor protection
The locked rotor protection protects the motor
from damage caused by excessively long startup. This may occur when, for example, the
rotor is locked, the driving torque is too high, or
impermissible voltage break down occurs.
If the permissible start-up time is longer than
the permissible locked rotor time the locked
rotor protection function is inadequate: then the
zero speed function has to be used (refer to
section 4.7).
The tripping time depends on the magnitude of
the largest phase of the starting current. The
following formula is valid:
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2
⎞
⎛I
t trip = ⎜ start ⎟ ⋅ t lr
⎝ I ⎠
with ttrip
Istart
I
tlr
−
−
−
−
tripping time
permissible start-up current
motor current (largest phase)
locked rotor time
The locked rotor protection only works during
start. If the motor status stays ‘start’ during ttrip,
MFR 7SJ551 energizes the locked rotor (trip)
output. If the motor status becomes ‘running’ or
‘stopped’ the locked rotor function becomes
inactive.
G88700-C3527-07-7600
MFR 7SJ551
Method of operation
The formula for the locked rotor protection
allows starting for a longer time for smaller
starting currents. This is a practical situation:
4.7
Zero speed protection
The zero speed function protects the motor
from damage caused by a locked rotor, when
the permissible start-up time is longer than the
permissible locked rotor time. In that case the
locked rotor protection cannot be used and a
binary tachometer built in the motor has to
provide a zero speed signal. This signal is
connected to the zero speed binary input.
4.8
when the motor is started with lower motor
voltage, the starting takes longer, but the
starting current is smaller.
The zero speed protection only works during
start. When the motor is starting and the rotor
is stalled, the binary tachometer energizes the
zero speed binary input and the zero speed
protection function jumps into the alarm
condition. If the binary input stays energized
during the detection time tzero the zero speed
(trip) output will be energized.
Motor start-up protection
Three different protection functions work at the
same time to protect the motor against
overheating during start-up:
• stator thermal overload protection
• rotor thermal overload protection
• locked rotor protection
By showing an example case the method of
operation of the start-up protection will be
explained.
From rest condition (‘stopped’) MFR 7SJ551
recognises a start-up when the motor current is
higher than the top current Itop (refer to figure
4.10):
crosses Itop downwards again; then the motor
status becomes ‘running’. When the motor is
overloaded now to current values higher than
Itop the motor status will stay ‘running’: it can
only become ‘start’ again when it becomes
‘stopped’ first.
If the motor current gets smaller than Ino load the
motor status becomes ‘stopped’ again.
stopped
0
running
Ino load
Iflc
start
Itop
Istart
I
Figure 4.10
Motor status
Itop = 1.125 · Iflc
with Itop − top current
Iflc − full load current
The motor status will become ‘start’. It stays
‘start’ as long as the motor current is larger
than Itop.
Normal starting behaviour for most motors is
that the motor current jumps to the starting
current very fast. As the rotor slowly begins to
turn the motor current slowly decreases. The
more turning speed the rotor achieves, the
faster the motor current decreases, until it
reaches normal load level (refer to figure 4.11).
From start condition MFR 7SJ551 recognises a
normal running state when the motor current
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
t
t
normal starting behaviour
rotor thermal overload curve
stator
rotor
tstart
normal
starting
behaviour
tstart
Istart
Iflc
kstator x Iflc krotor x Iflc
start
start
Figure 4.11
Istart
I>
start
start
Normal starting behaviour
Figure 4.13 Rotor thermal overload curve
during start
The stator thermal overload protection primarily
acts on relatively low overcurrrents when the
motor is running. It becomes active for currents
higher than kstat · Iflc (refer to figure 4.12).
t
locked rotor curve
t
stator
rotor
stator thermal overload curve
normal
starting
behaviour
tlr
tstart
kstator x Iflc krotor x Iflc
normal
starting
behaviour
tstart
Istart
I>
start
start
Figure 4.14
kstator x Iflc
Istart
Locked rotor curve
I>
start
start
Figure 4.12
Stator thermal overload curve
during start
The rotor thermal overload protection primarily
acts on higher currents during start. In most
cases (for start from cold condition) the rotor
thermal overload protection will trip earlier than
the stator thermal overload protection (refer to
figure 4.13).
When the manufacturer data prescribe a
maximum locked rotor time (often denominated
te) the locked rotor protection can be activated.
The locked rotor protection is active only during
motor status ‘start’. For a start from cold
condition the locked rotor curve will earlier
cause a trip in most cases than the rotor and
stator thermal overload curves (refer to figure
4.14).
¡Error! Argumento de modificador desconocido.
When the motor passes a successful start and
is running at full load current the rotor and
stator thermal reserves will decrease to an
equilibrium level (refer to figure 4.15). The
locked rotor curve is inactive when the motor
status is ‘running’. Notice that the rotor and
stator thermal curves are not ‘rigid’: they ‘float’
to equilibrium depending on the magnitude the
load current.
When the motor is stopped now the remaining
rotor and stator thermal capacities will slowly
increase again from equilibrium level (refer to
figure 4.16). Only after a long time the motor
will have cooled off completely and the rotor
and stator thermal reserves will be back at
100%.
G88700-C3527-07-7600
MFR 7SJ551
Method of operation
t
t
rotor
tlr
tstart
rotor
normal
starting
behaviour
locked rotor
stator
stator
kstator x Iflc krotor x Iflc
I>
Istart
kstator x Iflc krotor x Iflc
running
running
I>
start
start
Figure 4.15
Running at nominal current
Figure 4.17
Start from warm condition
t
If the rotor would lock at this moment, i.e.
motor current will stay at Istart level, the stator
thermal overload function will trip the motor
(refer to figure 4.18).
t
rotor
stator
kstator x Iflc krotor x Iflc
Istart
I>
stopped
stopped
Figure 4.16
condition
Stopped motor in warm
rotor
tlr
locked rotor
ttrip
stator
Istart
kstator x Iflc krotor x Iflc
If we would start again shortly after stopping
the motor, the rotor and stator thermal reserves
will not have increased noticeably. Figure 4.17
shows the start from this warm condition. The
‘rigid’ locked rotor protection curve is activated
again but in this case it is no longer the first
function which trips the motor.
4.9
Unbalance protection
4.9.1
General
MFR 7SJ551 is equipped with unbalance
protection, protecting all electric network
components against phase unbalance.
Furthermore, the unbalance protection detects
interruptions, short-circuits and swapped phase
connections of the current transformer circuits.
Single-phase and two-phase short-circuits can
G88700-C3527-07-7600
I>
start
start
Figure 4.18
Blocked rotor in warm condition
be detected even when the fault current is too
small to be detected by the overcurrent
protection.
For three-phase connection MFR 7SJ551 filters
out the fundamental wave of the phase currents
and separates it into symmetrical components
(negative sequence Iinv and positive sequence
Inorm). The unbalance protection evaluates the
magnitude of Iinv.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
The sequence of connections can be externally
selected either clockwise or counterclockwise,
by means of a binary input. When the sequence
direction is reversed, the calculation of the
inverse current and the calculation of the normal
current are exchanged.
For two-phase connection the following formula
is applicable:
Iinv = Imax − Imin
with Iinv
Imax
Imin
− inverse component of the phase
currents
− the largest of the two phase
currents
− the smallest of the two phase
currents
When the negative sequence current exceeds
the unbalance pick-up the unbalance protection
jumps into the alarm condition. Then every
sample period the tripping time is calculated
according to an extremely inverse characteristic:
t trip =
80
2
⎛ Iinv ⎞
⎜⎜ ⎟⎟ − 1
⎝ I2p ⎠
⋅ t2p
with ttrip − tripping time
I2p − unbalance pick-up
t2p − unbalance time multiplier
When the inverse current stays larger than the
unbalance pick-up during the tripping time, the
unbalance (trip) output is energized. The passed
time is distracted from the calculated actual
tripping time.
When the inverse current becomes smaller than
the pick-up value, the unbalance function jumps
back into the ‘no alarm’ condition.
4.10
Undercurrent protection
4.10.1
General
The undercurrent protection protects network
components against a decrease in current flow.
For motors this can be caused by a loss of or
decrease in motor load. Examples of such
situations are: loss of suction of pumps, loss of
G88700-C3527-07-7600
4.9.2
Unbalance protection of motors
The unbalance protection especially protects
motors switched by vacuum contactors with
associated fuses. When running on single phase
the motor develops small and pulsating torques.
With unchanged torque load the motor will
quickly be thermally overloaded.
Furthermore, thermal overloading of the motor
can arise by asymmetrical system voltage. Even
small unbalanced system voltages may lead to
large slip load currents because of the small
negative sequence reactances.
During start-up (motor status is ‘start’)
unbalance may occur because of closing time
differences of the circuit breaker phase
contacts. Tripping the motor for this reason is
undesirable, therefore for ‘rotating objects’ MFR
7SJ551 provides the possibility to set a delay
time tbypass. This bypass time is started at the
moment the motor status changes from
‘stopped’ to ‘start’. During the bypass time the
unbalance protection is inactive.
When the motor status is still ‘start’ after the
bypass time has expired, pick-up takes place
I
with rms , (with Irms the root mean square value
3
of the largest phase current) in stead of I2p.
When one phase drops out during start this is
detected immediately because the inverse
I
current will be larger than rms then. The
3
calculation of the tripping time stays unchanged
(with the original unbalance pick-up I2p).
After the motor status has changed to ‘running’
the function picks up with I2p.
airflow for fans or a broken belt in conveyors.
Because the cooling is limited severely these
situations may result in excessive overheating
of the motor, even when the motor is protected
by (current dependent) thermal overload
protection.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
For non-rotating objects the most customary
application of undercurrent protection is the
protection of capacitor banks against their being
switched on. Only when the undercurrent
protection picks up (no remaining capacitive
current) the circuit breaker may be closed
(figure 4.19).
the undercurrent protection jumps into the alarm
condition and the delay timer is started. After
the delay time tI< has elapsed the undercurrent
(trip) output is energized. When the phase
currents become larger than the pick-up value,
the undercurrent protection function jumps back
into the ‘no alarm’ condition.
For the undercurrent protection MFR 7SJ551
computes the fundamental wave of the phase
currents.
4.10.2
I<
closing coil
7SJ551
Figure 4.19
Protection of capacitor banks
During operation the function can be blocked
dynamically via a binary input even during pick
up of the protection. Refer to section 4.19
‘Block’ for detailed information.
Each phase current is compared with the pickup value I< which is applicable for all three
phases. Pick-up is separately indicated for each
phase. Pick-up occurs when the measured value
is smaller than the pick-up value. After pick-up
4.11
Motor undercurrent protection
Before start-up (motor status is ‘start’) the
current is zero: this is a pick-up condition for
the undercurrent protection. Tripping the motor
for this reason is undesirable, therefore for
‘rotating objects’ the undercurrent protection is
inactive when the motor status is ‘stopped’.
Furthermore, MFR 7SJ551 provides the
possibility to set a delay time tbypass. This bypass
time is started at the moment the motor status
changes from ‘start’ to ‘running’. During the
bypass time the undercurrent protection
function is inactive.
If the motor status is ‘running’ during the
bypass time and after expiration of the bypass
time all phase currents decrease under the
undercurrent pick-up value I<, the undercurrent
protection function jumps into the alarm
condition. If the motor status stays running and
all phase currents stay smaller than the
undercurrent pick-up value I< during tI<, the
undercurrent (trip) output is energized. When
the phase currents become larger than the pickup value or if the motor status becomes
‘stopped’, the undercurrent protection function
jumps back into the ‘no alarm’ condition.
Overtemperature protection (optional)
MFR 7SJ551 provides the possibility to
measure the temperature of network
components directly. This is especially useful
for protecting non-conducting parts of network
components against overheating.
For overtemperature protection temperature
sensors are necessary. The sensors is
connected to the temperature sensor inputs of
the (optional) interface unit. Depending on the
ordered type the interface unit has 2 or 8 inputs
¡Error! Argumento de modificador desconocido.
for temperature sensors. Temperature sensors
are normally mounted in:
bearings,
−
−
stator windings,
−
transformer cores,
−
coolants,
−
lubrication oil.
−
Temperature sensor inputs that are not
connected to a temperature sensor should be
G88700-C3527-07-7600
MFR 7SJ551
Method of operation
closed with a resistor (50 - 100 Ω) to maintain
the display value.
the alarm condition. When one of the
temperatures exceeds the corresponding trip
pick-up value the overtemperature protection
(trip) output is energized.
For each temperature sensor an alarm pick-up
and a trip can be set individually. Pick-up values
of 999 °C should be set to prevent unwanted
pick-ups of an unused temperature sensor.
When all temperatures become smaller than the
alarm pick-up value, the overtemperature
function jumps back into the ‘no alarm’
condition.
When one of the temperatures exceeds the corresponding alarm pick-up value the
overtemperature protection function jumps into
4.12
Low set overcurrent protection
The low set overcurrent protection protects
network components against high impedance
short-circuits. It can be used as definite time or
inverse time overcurrent protection. Three
standardized inverse time characteristics are
available for inverse time mode. In addition, a
user specified characteristic (custom curve) can
be defined. Two more characteristics are
available for earth faults. The trip time
characteristics and the applied formula are given
in the Technical data, refer to section 3.11. For
phase currents and for earth currents separate
characteristics can be set.
For the low set overcurrent protection MFR
7SJ551 computes the fundamental wave of the
phase and earth currents.
During operation the characteristics can be
switched over or blocked dynamically via binary
inputs even during pick-up of the protection. By
switching over to an instantaneous
characteristic (delay time is zero) rapid trip is
provided. Refer to section 4.14 ‘Curve switch’
and section 4.19 ‘Block’ for detailed
information.
The measured currents are fed to the relay via
the input transducers for each phase. The
inputs are galvanically isolated against the
electronic circuits as well as against each other.
To the earth current input either the residual
current of the phase current transformers or a
separate summation current transformer can be
connected. The earth current input is either a
regular earth current input (for high magnitude
earth currents) or a sensitive earth current input
(for low magnitude earth currents).
G88700-C3527-07-7600
4.12.1
Definite time overcurrent
protection
Each phase current is compared with the pickup value I> which is applicable for all three
phases. Pick-up is separately indicated for each
phase. Pick-up occurs when one of the phase
currents exceeds the pick-up value. After pickup the overcurrent protection jumps into the
alarm condition and the delay timer is started.
After the delay time tI> has elapsed the
overcurrent (trip) output is energized. When the
phase currents become smaller than the pick-up
value, the low set overcurrent protection
function jumps back into the ‘no alarm’
condition.
The residual (earth) current is processed
separately and compared with the earth
overcurrent pick-up value Ie>. The delay time tIe>
can be set individually.
4.12.2
Inverse time overcurrent
protection
Each phase current is compared with the pickup value Ip which is applicable for all three
phases. Pick-up is separately indicated for each
phase. Pick-up occurs when one of the phase
currents exceeds the pick-up value. After pickup the overcurrent protection jumps into the
alarm condition and the trip time delay is
calculated from the inverse time characteristic
and the magnitude of the fault current. The
passed time is distracted from the calculated
actual delay time. After the calculated delay
time has elapsed the overcurrent (trip) output is
energized. When the phase currents become
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
smaller than the pick-up value, the low set
overcurrent protection function jumps back into
the ‘no alarm’ condition.
The residual (earth) current is processed
separately and compared with the earth
overcurrent pick-up value Iep. The earth
overcurrent characteristic may differ from the
phase overcurrent characteristic; the associated
parameters can be set individually.
4.12.3
Custom curve overcurrent
protection
When the definite or inverse time overcurrent
protection function cannot cover the shortcircuit characteristic of the network component
a user specified characteristic can be defined.
Minimum 2 and maximum 15 I-t co-ordinates (I1
... I15) can be defined. The MFR 7SJ551 will
construct an I-t curve by using these coordinates and assuming straight lines between
the co-ordinates.
4.13
Method of operation
Each phase current is compared with the pickup value I1 which is applicable for all three
phases. Pick-up is separately indicated for each
phase. Pick-up is separately indicated for each
phase. Pick-up occurs when one of the phase
currents exceeds the pick-up value. After pickup the overcurrent protection jumps into the
alarm condition. The trip time delay is calculated
every sample period out of the line drawn
between the two I-t co-ordinates that lie closest
to the measured current. The passed time is
distracted from the calculated actual delay time.
After the calculated delay time has elapsed the
overcurrent (trip) output is energized. When the
phase currents become smaller than the pick-up
value, the low set overcurrent protection
function jumps back into the ‘no alarm’
condition.
The residual (earth) current is processed
separately and compared with the earth
overcurrent pick-up value Ie1. The earth
overcurrent characteristic may differ from the
phase overcurrent characteristic; the associated
parameters can be set individually.
High set overcurrent protection
The high set overcurrent protection protects
network components against low impedance
short-circuits.
For phase currents and for earth currents
separate parameters can be set.
For the high set overcurrent protection MFR
7SJ551 computes the fundamental wave of the
phase and earth currents.
During operation the characteristic can be
switched over or blocked dynamically via binary
inputs even during pick-up of the protection. By
switching over to an instantaneous
characteristic (delay time is zero) rapid trip is
provided. Refer to section 4.14 ‘Curve switch’
and section 4.19 ‘Block’ for detailed
information.
The measured currents are fed to the relay via
the input transducers for each phase. The
inputs are galvanically isolated against the
electronic circuits as well as against each other.
¡Error! Argumento de modificador desconocido.
For the earth current input either the residual
current of the phase current transformers or a
separate summation current transformer can be
connected. The earth current input is either a
regular earth current input (for high magnitude
earth currents) or a sensitive earth current input
(for low magnitude earth currents).
Each phase current is compared with the pickup value I>> which is applicable for all three
phases. Pick-up is separately indicated for each
phase. Pick-up occurs when one of the phase
currents exceeds the pick-up value. After pickup the high set overcurrent protection jumps
into the alarm condition and the delay timer is
started. After the delay time tI>> has elapsed
the high set overcurrent (trip) output is
energized. When the phase currents become
smaller than the pick-up value, the high set
overcurrent protection function jumps back into
the ‘no alarm’ condition.
The residual (earth) current is processed
separately and compared with the high set earth
overcurrent pick-up value Ie>>. The delay time
tIe>> can be set individually.
G88700-C3527-07-7600
MFR 7SJ551
4.13.1
Method of operation
Fast bus bar protection using
the reverse interlock scheme
The high set overcurrent protection can be
blocked via a binary input of the relay. A setting
parameter determines whether the binary input
operates in the normally open mode (i.e.
energize input to block) or in the normally
closed mode (i.e. energize input to release).
Thus the high set overcurrent protection can be
used as a fast bus bar protection in star
connected networks or in open ring networks
(ring open at one spot), using the reverse
interlock principle. This is used in high voltage
systems.
Reverse interlocking means that the high set
overcurrent protection can trip within time tI>>,
which is independent of the low set overcurrent
4.14
I>
fault detection
0.6 s
I>
I>
I>>
0.9 s 0.3 s
Figure 4.20
fault detection
0.6 s
blocking of I>>
Reverse interlock principle
Curve switch
With the curve switch function MFR 7SJ551
provides the possibility to adapt the overcurrent
characteristics during motor or transformer
inrush by setting the pick-up values higher.
Furthermore, by switching over from a time
delayed to an instantaneous characteristic
(delay time is zero) rapid trip is provided.
For low set overcurrent protection and for high
set overcurrent protection two sets of I-t coordinates can be defined. With the curve switch
function the MFR 7SJ551 can be parametrized
to use set 1 or set 2, controlled by motor status
or a binary input.
Three curve switch modes can be selected:
continuous mode: MFR 7SJ551 switches
−
from curve 1 to curve 2 during the
activation of the curve switch binary input,
4.15
protection time tI> if it is not blocked by pick-up
of one of the next downstream feeder
protections (figure 4.*). Therefore, the
protection which is closest to the fault will
always trip within a short time, as it cannot be
blocked by a relay behind the fault location. The
low set overcurrent time stages tI> or Ip operate
as delayed back-up stages.
−
−
pulse mode: MFR 7SJ551 switches from
curve 1 to curve 2 during the curve switch
time tCS, after the activation of the curve
switch binary input,
status mode (only for motors): depending
on motor status MFR 7SJ551
automatically switches from curve 1 to
curve 2. For the status mode two different
options can be selected:
• status = stopped/start: when the
motor status is ‘stopped’ or ‘start’
curve 2 is active, when the motor
status is ‘running’ curve 1 is active,
• status = running: when the motor
status is ‘running’ curve 2 is active,
when the motor status is ‘stopped’ or
‘start’ curve 1 is active.
Directional earth fault protection (optional)
The directional earth fault protection can be
used in isolated or arc compensated networks
G88700-C3527-07-7600
to discriminate the earth fault direction. Trip
commands for earth fault overcurrent will only
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
be activated if the direction of the earth fault
current corresponds with the selected direction.
The residual voltage U0 is one of the two
conditions for release of the directional
determination. U0 is the voltage measured at the
terminals of an open delta voltage transformer.
In order to detect earth currents, the two-stage
low set overcurrent protection (refer to section
4.12) or high set overcurrent protection (refer to
section 4.13) must be set. When the earth fault
direction function is enabled, the denomination
of the pick-up values changes to Iφ>, Iφp and Iφ>>
(in stead of Ie>, Iep and Ie>>).
The earth fault direction protection does not
process the magnitude of the earth current but
the component which is at right angle to a
settable directional symmetry axis. A
precondition for determination of the fault
direction is that one of the current magnitude
stages has picked up and that the residual
voltage exceeds the displacement voltage.
When the measured residual voltage U0 exceeds
the pick-up value Ustrt during the pick-up delay
tUstrt the directional determination is released.
The directional earth fault protection picks up as
soon as
− the directional determination is released
− the earth fault direction current Iφ exceeds
the overcurrent threshold value Iφ>
− the direction of the earth fault is in the
selected direction.
The trip delay time is calculated according to
the selected time characteristic.
After pick-up the directional earth fault
protection jumps into the alarm condition and
the delay timer is started. After the delay time
tIφ> has elapsed the directional earth fault (trip)
output is energized. When the zero sequence
voltage U0 decreases below Ustrt or when the
earth fault direction current Iφ decreases below
Iφ> or when the direction changes, the
directional earth fault protection function jumps
back into the ‘no alarm’ condition.
Method of operation
4.15.1
Cos φ determination
For resistance-earthed networks or networks
earthed with a Petersen coil cos φ determination
is used.
When an earth fault occurs the Petersen coil
superimposes a corresponding inductive current
on the capacitive earth fault current, so that
this capacitive current at the fault spot is
compensated. However, dependent upon the
point of measurement in the network the
resultant measured current can be inductive or
capacitive and the reactive current is therefore
not suitable for the determination of direction.
In this case only the ohmic residual current
which results from the losses of the Petersen
coil can be used for directional determination.
This earth fault ohmic current is only a few
percent of the capacitive earth fault current.
It must be noted that, dependent upon the
location of the protective relay, a considerable
reactive component may be superimposed,
which, in the most unfavourable cases, can
attain a value of fifty times the value of the
active component. Despite the extremely high
accuracy the calculation algorithm is then
inadequate if the current transformers do not
exactly convert the primary values.
In case of cos φ determination the active power
P is the decisive factor. The direction is
forwards if P is positive:
P = U0 ⋅ IE ⋅ cos φ
The earth fault component is calculated
according to the following formula:
Iφ =
P
U0
The same is valid for the inverse time
characteristics and for the high set overcurrent
stage Iφ>>.
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
with P
U0
Ie
Iφ
Method of operation
− active power in the earth current
path
− residual voltage
− earth current
− component of the earth current
which is at a right angle with the
directional symmetry axis
with Q
path
− reactive power in the earth current
forward
(Q>0)
IE
Iφ
IE capacitive earth
capacitive earth
fault load
fault load
U0
φ
U0
φ
Iφ
inductive earth fault
load
backward
(Q<0)
Figure 4.21
4.15.2
Sin φ determination
Sin φ determination
For isolated networks sin φ determination is
used.
The earth fault current flows as capacitive
current from the healthy lines via the measuring
spot to the fault spot. This capacitive current
determines the direction.
In case of sin φ determination the reactive
power Q is the decisive factor. The direction is
forwards if Q is positive. The earth fault
component is calculated according to the
following formula:
Iφ =
G88700-C3527-07-7600
Q
U0
inductive earth fault
load
backward
(P<0)
forward
(P>0)
Figure 4.22 Cos φ determination
4.15.3
Sensitivity improvement by
shifting the symmetry axis
The symmetry axis can be shifted by up to ±45°
(settable rotation angle φe, refer to figure 4.23).
Thus it is possible to achieve maximum
sensitivity.
4.15.4 Correcting the angular error of
the core balance transformer
The sensitive measurement input circuit of the
relay for directional earth fault protection
permits an extremely high sensitivity for the
directional determination of the wattmetric
residual current. In order to utilize this
sensitivity it is recommended that a core
balance current transformer is used for the earth
fault detection. As even these transformers
have an angle error, MFR 7SJ551 allows the
setting of factors which, dependent on the
reactive current, will correct the error angle.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Dependent of the value of the expected earth
current Ie the angular error of the core balance
current transformer can be corrected in three
ranges:
Method of operation
performed. In any case the faulted cable can be
clearly determined.
− δ1
Ie ≤ 100 mA
− δ2 100 mA < Ie ≤ 200 mA
− δ3
Ie > 200 mA
φe
IE
φ
4.15.5
Earth fault location
By means of the directional indication the earthfaulted line in radial networks is located. Since
all circuits on a bus bar carry a capacitive partial
current, the measuring spot on the faulted line
in an isolated network covers almost the entire
prospective earth fault current of the network;
in compensated networks the wattmetric
residual current from the Petersen coil flows
through the measuring spot. For the faulted line
or cable a definite ‘forwards’ decision will
result, whilst in the remaining circuit a ‘reverse’
indication will be given unless the earth current
is so small that no measurement can be
4.16
Iφ
U0
forward
(P>0)
backward
(P<0)
Figure 4.23
Shifting the symmetry axis
Undervoltage protection (optional)
The undervoltage protection protects network
components against too low voltage.
up of the protection. Refer to section 4.19
‘Block’ for detailed information.
For the undervoltage protection MFR 7SJ551
contains one voltage input. This means only one
phase voltage can be measured. The user
determines whether the measured voltage Uin is
a phase to phase voltage by parametrizing it as
Uln, a phase to earth voltage by parametrizing it
as Uph and a residual voltage by parametrizing it
as U0.
The measured voltage is compared with the
pick-up value U<. Pick-up occurs when the
measured value is smaller than the pick-up
value. After pick-up the undervoltage protection
jumps into the alarm condition and the delay
timer is started. After the delay time tU< has
elapsed the undervoltage (trip) output is
energized. When the measured voltage becomes
larger than the pick-up value, the undervoltage
protection function jumps back into the ‘no
alarm’ condition.
During operation the function can be blocked
dynamically via a binary input even during pick-
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G88700-C3527-07-7600
MFR 7SJ551
4.17
Method of operation
Overvoltage protection (optional)
The overvoltage protection protects network
components against too high voltage.
For the overvoltage protection MFR 7SJ551
contains one voltage input. This means only one
phase voltage can be measured. The user
determines if the measured voltage Uin is a
phase to phase voltage by parametrizing it to
Uln, a phase to earth voltage by parametrizing it
to Uph and a residual voltage by parametrizing it
to U0.
For the low set stage the measured voltage is
compared with the pick-up value U>. Pick-up
occurs when the measured value exceeds the
pick-up value. After pick-up the overvoltage
protection jumps into the alarm condition and
the delay timer is started. After the delay time
4.18
For the high set stage the measured voltage is
compared with the pick-up value U>>. Pick-up
occurs when the measured value exceeds the
pick-up value. After pick-up the overvoltage
protection jumps into the alarm condition and
the delay timer is started. After the delay time
tU>> has elapsed the overvoltage (trip) output is
energized. When the measured voltage becomes
smaller than the pick-up value, the overvoltage
protection function jumps back into the ‘no
alarm’ condition.
Breaker failure protection
In order to supervise correct functioning of the
circuit breaker, MFR 7SJ551 checks whether
the current becomes zero after a trip signal has
been given. When the trip command is
generated a timer tbf is started. The timer
continues to run for as long as the trip
command is maintained. If the circuit breaker
does not respond to the trip command the timer
runs to its set limit. If the then measured
current is higher than a settable level Ibf the
breaker failure protection energizes a second
relay output to trip the upstream circuit breaker
to clear the fault.
4.19
tU> has elapsed the overvoltage (trip) output is
energized. When the measured voltage becomes
smaller than the pick-up value, the overvoltage
protection function jumps back into the ‘no
alarm’ condition.
Instead of by the algorithm described above,
start of the breaker failure protection can be
initiated by an external protection relay. The trip
signal of the external protection device is
coupled into MFR 7SJ551 via a binary input.
The timer tbf is started. If the measured current
is higher than a settable level Ibf after tbf has
elapsed, the breaker failure protection energizes
the breaker failure protection relay output to
cause the circuit breaker to clear the fault. The
breaker failure protection function can only be
deactivated if the measured current becomes
smaller than Ibf.
Block
With the block function MFR 7SJ551 provides
the possibility to block the overcurrent,
undercurrent and undervoltage characteristics
during motor or transformer inrush.
Three block modes can be selected:
continuous mode: MFR 7SJ551 activates
−
the block function during the activation of
the block binary input,
pulse mode: MFR 7SJ551 activates the
−
block function during the block time tBLOCK,
G88700-C3527-07-7600
−
after the activation of the block binary
input,
status mode (only for motors): depending
on motor status MFR 7SJ551
automatically activates the block function.
For the status mode two different options
can be selected:
• status = stopped/start: when the
motor status is ‘stopped’ or ‘start’ the
block function is active, when the
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
motor status is ‘running’ the block
function is inactive,
• status = running: when the motor
status is ‘running’ the block function is
4.20
Method of operation
active, when the motor status is
‘stopped’ or ‘start’ the block function
is inactive.
External command
With the external command function an
immediate trip can be generated by activating a
binary input, for example to make an emergency
stop.
4.21
After activating the external command binary
input a delay timer teXT is started. If the binary
input continues to be activated during teXT the
external command output will be energized after
teXT has elapsed.
Circuit breaker position
With the circuit breaker position function the
position of the circuit breaker can be indicated.
4.22
After the circuit breaker position binary input is
activated the circuit breaker position LED
indicator will be energized.
Ancillary functions
The ancillary functions of MFR 7SJ551 include:
− processing of annunciations
− storage of short-circuit data for fault
recording
− operational measurements
− test routines
− monitoring functions
4.22.1
Processing of annunciations
After a fault in the protected component
information concerning the response of the
protective device and knowledge of the
measured values are important for an exact
analysis of the history of the fault. For this
purpose the MFR 7SJ551 provides annunciation
processing which is effective in three directions.
Indicators and binary outputs (signal relays)
Important events and conditions are indicated
by optical indicators (LED) on the front plate.
MFR 7SJ551 also contains signal relays for
remote signalling. All of the signals and
indications can be marshalled freely. In section
6.11 the marshalling facilities are described in
detail.
¡Error! Argumento de modificador desconocido.
The output relays can be arranged to latch or to
be self-resetting. The general alarm LED, the
pre-alarm LED and the general trip LED are
memorized. The four freely programmable LEDs
(optional) can be arranged to be memorized or
to be self-resetting.
The memories of the LEDs can be reset
− locally, by pushing the ‘reset indicators‘
button (RI) on the front plate;
− remotely, by energizing the remote reset
binary input;
− via the operating interface.
The latching of the output relays can be reset:
− locally, by pushing the ‘reset indicators‘
button (RI) on the front plate
− remotely, by energizing the remote reset
binary input
− via the operating interface
− automatically, after elapsing of a settable
reset time treset
Sometimes indicators and relays indicate
conditions, which naturally should not be
stored. In these cases the indicators cannot be
reset until the originating criterion has
disappeared.
G88700-C3527-07-7600
MFR 7SJ551
A green LED indicates readiness for operation
(‘on line’). This LED is illuminated when the
microcontroller is working correctly, the unit is
not faulty and performing its protection task.
The LED extinguishes when the self-checking
function of the microcontroller detects a fault or
when the auxiliary voltage is absent. The ‘on
line’ LED will flash when there is a non-fatal
defect in the real time clock module, for
example an empty battery.
With the auxiliary voltage present but with an
existing internal fault or with the unit in off line
(programming) mode a red LED (‘monitor’)
illuminates and the outputs will be blocked.
Information on the display panel, to a personal
computer or to a substation automation system
Events and conditions can be either read off in
the display on the front plate of the unit (using
the keyboard) or transferred to a personal
computer or a substation automation system
connected to the serial interface (optional). MFR
7SJ551 outputs selectable operating
information like operational measured values or
motor status and also contains several event
buffers for operating messages or fault
annunciations. The fault inception is indicated
with the absolute time of the operating system.
The sequence of events is tagged with the
relative time referred to the pick-up time.
For using a personal computer or
communication with a substation automation
system the MFR 7SJ551 interface module has
to be connected. This module can either be
ordered together with the relay unit by choosing
the appropriate ordering number (refer to
section 2.3.1) or be ordered separately later on
(refer to section 2.3.2). Normally no special
arrangements are necessary to operate the relay
after connecting the interface module.
For setting and evaluating MFR 7SJ551 the
personal computer has to be loaded with the
software program ‘Communication Utility MFR
7SJ551’. This allows the user to comfortably
set the relay and analyze events and faults by
means of systematic screen use and graphical
aids. Additionally, the data can be documented
on a printer or stored on a floppy disk.
MFR 7SJ551 stores the data of the last three
events; if a fourth event occurs the first event is
overwritten in the event memory.
G88700-C3527-07-7600
Method of operation
One of the binary input signals can be transmitted via the serial interface (‘serial event’) to
the substation automation system.
4.22.2 Fault event data storage and
transmission (optional)
The instantaneous values of the measured
values
iL1, iL2, iL3, ie, uin
are sampled at 1 ms intervals (for 50 Hz) and
stored in a circulating shift register. In case of a
fault, the data are stored over a selectable time
period, with a maximum of 3 seconds. Only one
fault record is stored at a time. If the interface
unit is connected to the relay unit during the
fault, the fault data are available for fault
analysis. For each new event the old event is
overwritten by the new fault data.
The data can be transferred to a connected
personal computer via a serial interface (optic
fiber or RS485, selectable) on the interface unit
and evaluated by the ‘Communication Utility
MFR 7SJ551’ program. The currents are
referred to their maximum values, normalizes to
their rated values and prepared for graphic
visualization.
The fault record data can also be transmitted to
a substation automation system via one of the
serial interfaces. Evaluation of the data is made
in the substation automation system, using
appropriate software programs.
When the data are transmitted to a personal
computer or to a substation automation system,
read out can proceed automatically, optionally
after pick-up or after trip. The following then
applies:
− the interface unit of the relay signals the
availability of fault record data
− the data remain available for recall until they
are overwritten by new data
− a transmission in progress can be aborted by
the central unit of the control system.
Alternatively, the fault recording can be
triggered by applying an external binary input
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Method of operation
signal. The recording time is fixed at 3 seconds,
directly after the triggering.
4.22.5
4.22.3 Operational value
measurements
For local recall or transmission of data, the first
harmonic values of the phase currents, the
earth current and the voltage (optional) are
available. When the thermal overload protection
is active, the calculated thermal reserve and the
largest true root mean square current value can
be read out. For motors the rotor thermal
reserve, the stator thermal reserve and the
motor status are displayed. With an interface
unit containing RTD inputs the measured
temperatures can be read out.
The following items can be recalled:
− iL1, iL2, iL3, ie (Iφ)
− uin
− θ or θstator, θrotor
− ITRUe RMS
− I2
− T1 ... Tn
− motor status
4.22.4
phase and earth currents in
primary amperes
voltage in primary volts
thermal reserve in %
largest true root mean
square current value in
primary amperes
inverse current in primary
amperes
temperatures measured by
the 2 or 8 RTD elements in
degrees Celsius
three possible modes: stop
- start - running
Demand ampere meter
The demand ampere meter allows the user to
check correct dimensioning of network
components and makes special external
arrangements unnecessary.
The demand ampere meter displays
− the dynamic 8 minutes average of the
measured currents
− the maximum 8 minutes average of the
measured currents since the last reset
− the dynamic 15 minutes average of the
measured currents
− the maximum 15 minutes average of the
measured currents since the last reset.
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Test facilities
MFR 7SJ551 allows simple checking of the
tripping circuit and the circuit breaker as well as
interrogation of the state of all binary inputs and
outputs. Initiation of the test can be given from
the front keyboard or via one of the serial
interfaces with a personal computer.
4.22.6
Hardware monitoring
MFR 7SJ551 incorporates comprehensive
hardware monitoring functions.
The hardware is monitored for faults and
inadmissible functions, from the measured value
inputs to the output relays. In detail this is
accomplished by monitoring:
− Auxiliary and reference voltages
Failure or switch-off of the auxiliary voltage
automatically puts the system out of
operation; this status is indicated by the
breaking contact of the ‘monitor’ relay and
the illumination of the ‘monitor’ LED.
Transient dips in supply voltage of less than
40 milliseconds (for rated auxiliary voltage
higher than 110 V DC) will not disturb the
functioning of the relay.
− Output channels
The output relays are controlled by two
command and one additional release channel.
As long as no pick-up condition exists, the
microcontroller makes a cyclic check of
these output channels for availability, by
exciting each channel one after the other and
checking for change in the output signal
level. Change of the feed-back signal to low
level indicates a fault in one of the control
channels or in the relay coil. This condition
automatically leads to alarm and blocking of
the output.
− Memory modules
After the relay has been connected to the
auxiliary supply voltage, the RAM memory is
checked by writing a data bit pattern and
G88700-C3527-07-7600
MFR 7SJ551
reading it.
The further memory modules are periodically
checked for fault by
• formation of the modulus for the EPROM
program memory and comparison of it
G88700-C3527-07-7600
Method of operation
with a reference program modulus stored
there
• formation of the modulus of the values
stored in the EEPROM parameter memory
and comparison of it with a newly
determined modulus after each parameter
change.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
5
Installation instructions
Installation instructions
!
Warning
The successful and safe operation of this device is dependent on proper handling and installation
by qualified personnel under observance of all warnings and hints contained in this manual.
In particular the general erection and safety regulations (e.g. IEC, DIN, VDE and the national
standards) regarding the correct use must be observed. Non-observance can result in death,
personal injury or substantial property damage.
5.1
Unpacking and repacking
When dispatched from the factory, the equipment is packed in accordance with the guidelines
laid down in DIN 40046 part 7, which specifies
the impact resistance of packaging.
This packing shall be removed with care, without
force and without the use of inappropriate tools.
The equipment should be visually checked to
ensure that there are no external traces of
damage.
It must also be checked whether the order
number (on the top of the housing) of the relay
corresponds with the ordered relay type. A
possibly ordered optional interface unit will be
packed separately, but shipped in the same box
as the relay unit.
The packing can be re-used for further transport
when applied in the same way. If alternative
packing is used, this must provide the same
degree of protection against mechanical shock,
as laid down in DIN 40046 part 7 (class 23).
¡Error! Argumento de modificador desconocido.
5.2
Preparations
The operating conditions must comply with VDE
0100/5.73 and VDE 0105 part 1/7.83, or
corresponding national standards for electrical
power installations.
!
Caution!
The modules of digital relays contain
CMOS circuits. These shall not be
withdrawn or inserted under live
conditions! The modules must be handled
in such a way that any possibility of
damage due to static electrical discharges
is excluded. During any necessary
handling of individual modules the
recommendations relating to the handling
of electrostatically endangered
components (EEC) must be observed.
In installed conditions, the modules are in no
danger.
G88700-C3527-07-7600
MFR 7SJ551
5.2.1
Mounting and connections
Panel flush mounting or cubicle installation
− Lift up both the labelling strips on the lid of
the unit and remove the cover to gain access
to the four holes for the fixing screws.
− Insert the unit into the panel cut-out and
secure it with the fixing screws. For
dimensions refer to figure 2.3.
− Connect the earthing screw on the rear of the
relay unit to the protective earth of the panel
or the cubicle.
− Make a solid low-ohmic and low-inductive
operational earth connection between the
earthing surface at the rear of the unit using
at least one standard screw M4 and the
earthing continuity system of the panel or
cubicle; recommended grounding strap DIN
72333 form A, e.g. order number 15284 of
Messrs Druseidt, Remscheid, Germany.
− Make connections via the screwed or snap-in
terminals of the sockets of the housing.
Observe labelling of the individual connector
modules to ensure correct location: observe
the maximum permissible conductor crosssections. The use of the screwed terminals is
recommended; snap-in connection requires
special tools.
Installation instructions
Auxiliary voltage
The auxiliary supply voltage is
−
24 V - 60 V DC or
− 110 V - 250 V DC and 110 V - 230 V AC
The supply voltage selection is fixed according to
the order designation. The power consumption is
about 22 W maximum.
Rated currents
MFR 7SJ551 has three (R, T and e) or four (R, S,
T and e) current input modules with a rated
current In of 1 A or 5 A. On the backside the
relay is fitted with connection terminals for 1 A
and connection terminals for 5 A. The current
inputs must be connected to the secondary
windings of a current transformer with a
minimum accuracy of 10P10. The current
transformer ratio can be set as a parameter
value. For sensitive Ie measuring a different
current circuit is available only suited for a rated
current In = 1 A. The selection for a normal or a
sensitive earth current input is fixed according to
the order designation.
Control DC voltage of binary inputs
The minimal version of MFR 7SJ551 is fitted
with two binary control inputs. MFR 7SJ551
with extended I/O has 5 binary control inputs.
The control voltage range is 24 V - 250 V DC or
110 V - 230 V AC. The inputs can be configured
either normally open or normally closed.
Panel surface mounting using a 7SJ55 surface
mounting bracket
− Assemble the surface mounting bracket to the
panel. For the dimensions refer to figure 2.4.
5.2.3
Checking the (optional)
interface unit transmission link
− Insert the unit into the surface mounting
bracket cut-out and secure it with the fixing
screws.
− Mount the interface unit to the relay unit
according to figure 2.1
5.2.2
− Connect the earthing screw of the interface
unit to the protective earth of the panel or the
cubicle.
Checking the rated data
The rated date of MFR 7SJ551 must be checked
against the plant data. This applies in particular
to the auxiliary supply voltage, the rated current
of the current transformers, the input range of
the binary control inputs and the switching
capacity of the output relay contacts.
G88700-C3527-07-7600
− Make connections via the male connector for
the RTD temperature sensors (optional).
Observe labelling of the female connector to
ensure correct location.
− Make connection with a 9-pole make D
connector for the RS-485 interface for the
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
data communication with a personal
computer.
− Make connection with the fibre optic
interface:
• unscrew the protective caps at both
FSMA connectors
• plug on the optical fibre cable terminal
carefully; observe the designation of
transmitter and receiver end; the
transmitter terminal of MFR 7SJ551 (light
grey) must be connected to the receiver
terminal and the receiver terminal of MFR
7SJ551 (dark grey) must be connected to
the transmitter terminal
• tighten the cap nuts without force and
without use of tools
• observe the permissible bending radius of
the fibre optic cable.
− Check if the fibre optic interface is set to the
desired signal position:
• the factory setting for the fibre optic
interface is ‘light off’
• if the normal signal position should be
changed in ‘light on’ open the serial
interface housing and change the position
of the plug jumpers X3 and X4 each from
1 - 2 to 2 - 3 according to figure 5.1. The
jumpers are situated on the main board of
the serial interface near the connection
terminals of the optical fibre cable; close
the housing.
Installation instructions
of the binary inputs and outputs are described in
section 6.11.
5.2.5
!
Checking the connections
Warning
Some of the following test steps are
carried out in presence of hazardous
voltages. They shall be performed by
qualified personnel only which is
thoroughly familiar with all safety
regulations and precautionary measures
and pay due attention to them. Nonobservance can result in severe personal
injury.
− Switch off the circuit breakers for the
auxiliary supply voltage.
− Check the continuity of all the current
transformer circuits and the (optional)
voltage transformer circuit against the plant
and connection diagrams:
• Are the current and voltage transformers
earthed correctly?
• Are the polarities of the current and
voltage transformer connections
consistent?
• Is the phase relationship of the current
transformers correct?
• Is the polarity of the voltage transformer
correct?
− If test switches have been fitted in the
secondary circuits, check their function.
Check if the current transformer secondary
circuits are automatically short-circuited in
the ‘test’ position.
Figure 5.1
5.2.4
Jumper setting optical interface
Connections
General and connection diagrams are shown in
Appendix A and B. The marshalling possibilities
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− Fit a corresponding ampere meter in the
auxiliary power circuit, range approx. 1 A.
− Close the auxiliary voltage supply circuit
breaker, check the polarity (for the DC
version) and the magnitude of the voltage at
the terminals of the unit.
− The measured current consumption should
correspond to a power consumption of 14 -
G88700-C3527-07-7600
MFR 7SJ551
18 W. Transient movement of the ampere
meter pointer only indicates the charging
current of the storage capacitors.
− Coming from the manufacturer the display
will show:
OPERATING MODE
ON LINE
and the red ‘monitor’ LED will light up a few
seconds after applying the auxiliary
voltage.
− Open the circuit breaker for the auxiliary
power supply.
G88700-C3527-07-7600
Installation instructions
− Remove the current ampere meter and
reconnect the auxiliary voltage supply leads.
− Thoroughly check the tripping command
output circuits to the circuit breaker.
− Thoroughly check the control wiring to and
from other devices including the signal
circuits.
− For setting mode and for operative (‘on line’)
mode the auxiliary supply voltage circuit
breaker should be closed.
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MFR 7SJ551
6
Operating instructions
6.1
Safety precautions
!
Warning
All safety precautions which apply for
work in electrial installations are to be
observed during tests and commissioning.
6.2
Dialogue with the relay
Setting, operation and interrogation of MFR
7SJ551 can be carried out via the keyboard,
display panel and LED's located on the front
plate. All the necessary operating parameters can
be entered and all the information can be read
out from the frontplate. Additionally, operation is
possible via the serial interface by means of a
personal computer.
6.2.1
Display panel
The display panel is a 32 character display (two
lines of 16 characters) and is used to visualize all
communication to and from MFR 7SJ551. The
language is English or German. In the display
clearly understandable text is displayed, which
makes comfortable parametrization and
evaluation possible.
The display can also be used for ampere
metering.
6.2.2
Keyboard
Arrow keys
With the arrow keys ‘È’, ’Ç’ and ’Æ’ the user
can move to the different menu parts, following
the menu map. These keys can be depressed
with closed front cover.
Some parameters only have distinct values. For
setting these parameters a right arrow (Æ) in the
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Operating instructions
right most digit will appear. Selection of such a
value occurs with the Æ key.
A continuous depressing of the È and Ç keys
will cause a fast presentation of the menu, in
accordance with the existing setting.
Reset indicators key
With the key for resetting indicators ‘RI’
memorized indicators and output relays can be
reset. This key can be depressed with closed
front cover.
Decimal keys ‘0 - 9’
Function:
The decimal keys allow the user to
alter the currently selected
parameter value or setpoint value.
Effect:
A figure in accordance with the decimal key will be inserted at the right
most digit of the second row of the
display while already present digits
(or a decimal point) are shifted one
position to the left. Depressing these
keys while MFR 7SJ551 is ‘on line’
has no effect.
Decimal point key ‘.’
Function:
The decimal point key allows the use
of a decimal point in the currently
selected parameter value or setpoint
value.
Effect:
A decimal point will be inserted at
the right most digit at the second
row of the display, while already
present digits are shifted one
position to the left. The decimal
point key can only be used once in a
parameter value or a set point value.
The first digit may be a decimal
point so 0.015 can be entered as
.015. Depressing this key while MFR
7SJ551 is ‘on line’ has no effect.
Backspace key ‘BS’
Function 1: The backspace key allows the user
to delete the right most digit or
decimal point of the currently
selected parameter value or setpoint
value.
Effect 1:
Deletes the right most digit or
decimal point of the currently
selected parameter value or setpoint
value of the second row of the
display, while already present digits
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
and decimal point are shifted one
position to the right.
Function 2: With the backspace key the user
confirms the setting if MFR 7SJ551
asks for confirmation with the text
"TYPE BACKSPACE".
Effect 2:
MFR 7SJ551 accepts the execution
of special actions such as switching
from ‘on line’ to ‘off line’ and vice
versa. Depressing any other key will
cancel the confirmation action.
Representation of numerical values
Numerical values can have the following
appearance:
range
0 - 1
1 - 10
1 - 100
> 100
number of decimals
behind the point
3
2
1
0
example
.123
6.42
16.8
742
If a time needs more than 4 digits before the
decimal point the unit s (seconds) can be
changed to m (minute) or h (hours) with the Æ
key.
ALARM indicator will light up, indicating that the
protected device will get into thermal overload in
the near future if no special measures are taken
or no load decrease occurs.
Alarm (yellow)
If any alarm condition is detected by MFR
7SJ551 the ALARM indicator will light up.
Trip (red)
If any trip condition is detected by MFR 7SJ551
the TRIP indicator will light up.
Monitor (red)
Whenever MFR 7SJ551 is not performing its protection functions, the MONITOR indicator will
light up. It indicates that MFR 7SJ551 is in ‘off
line’ mode, which allows parameters to be
changed, or that MFR 7SJ551 has detected an
internal fault and is out of operation for that
reason.
LED 1 to LED 4 (yellow, optional)
These 4 LED indicators can be used to indicate
specific alarm or trip conditions, among other
things. It is advisable to indicate the chosen
meaning of each LED indicator on its left side
using the special sticker delivered together with
the relay.
If negative values are possible the sign of the
value can be changed with the Æ key.
6.2.4 Operation with a personal
computer
6.2.3
LED indicators
On line (green)
Whenever MFR 7SJ551 is performing its
protection functions, the ON LINE indicator will
light up. If a non-fatal internal fault is detected
this indicator will blink.
A personal computer (industrial standard) allows
all the appropriate setting, initiation of test
routines and read-out of data, with the comfort
of screen-based visualisation and a menu-guided
procedure. The PC Program ‘Communication
Utility MFR 7SJ551’ is available for setting and
processing of all digital protection data.
Pre-alarm (yellow)
If the remaining thermal capacity has decreased
under the adjustable alarm value, the PRE-
All data can be read in from, or copied onto
diskette or documented on a connected printer.
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MFR 7SJ551
6.2.5
Operating instructions
Front view of the relay
Two line display
(LCD) with 16
characters each
Indication operative
mode (green)
Alarm indication
(yellow)
Overload indication
(yellow)
Trip indication (red)
Reset microcontroller
hole
Indication OFF LINE
mode / indication unit
faulty (red)
LED 1 to 4 (yellow)
can be marshalled
Arrow keys
Numerical keyboard
Reset indicators key
Figure 6.1
Front view with operating keyboard and display panel
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G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
6.3
Parameterizing procedure
6.3.1
Menu structure
The operating interface is built up by a
hierarchically structured menu tree, which can
be passed through by means of the scrolling
keys ‘È’, ’Ç’ and ’Æ’. Thus, each operation
object can be reached.
In figure 6.2 the menu structure is shown.
From the initial display, the key È is used to
switch to the first operation item SETTINGS,
which contains all setting and configuration
blocks of the device (see figure 6.3). Key Æ is
pressed to change to the next operation level.
The display shows the first item DEVICE DATA,
which is described in section 6.6. Further
parameter blocks can be called up with the
scrolling keys È or Ç.
Figure 6.2
Menu structure
Pressing the key Æ leads to the third operation
level where the individual functions and values
are set; refer to figure 6.3. They are explained in
detail in the following sections.
È
OPERATING
MODE
OFF LINE
È
SETTINGS
OFF LINE
È
È
SETTINGS
Æ DEVICE DATA
È
È
LINE
Æ FREQUENCY
fn
[Hz]
50
È
FULL LOAD
I-flc [In]
1.00
È
DEVICE TYPE:
NONROTATING
È
NON-ROTATING
k
1.10
È
SETTINGS
CHANNELS
È
Figure 6.3
Setting example
In the following sections each menu item is
explained. There are three forms of display:
− Menu items without request for operator input
menu. No input is expected. By using keys È
or Ç the next or previous menu item can be
selected. By using the key Æ the next
operation level can be reached.
− Menu items which require numerical input
These menu items guide you through the
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
These menu items display parameters that
have a numerical value. When the relay is
delivered a value has been preset. In the
following sections, this value is shown. If this
value is to be retained, no other input is
necessary. If the value needs to be altered,
you can use the numerical keyboard, as
described in section 6.2.2.
− Menu items which require a choice
These menu items display parameters which
only have a limited number of possible values
or applicable text inputs. When the relay is
delivered, a value or text has been preset. In
the following sections, this setting is shown.
If this setting is to be retained, no other input
is necessary. If the setting needs to be
altered, you can use the key Æ.
For each of the menu items, the possible
parameters and text are given in the following
sections.
6.3.2
Initial display
When the relay is switched on, shortly some
start-up messages appear. After that, the initial
display appears.
OPERATING MODE
OFF LINE
The SETTINGS block is reached by pressing the
key È.
After altering a setting, scrolling down with the
key È causes the setting to be saved. The
altered parameters are permanently secured in
EEPROMs and protected against power outage.
6.4
Main menu (OFF LINE)
È
OPERATING
MODE
OFF LINE
Æ
È
This menu item is used for changing the OFF
LINE programming mode into the ON LINE
protective mode and vice versa. Refer to section
6.13 for a detailed description.
If there are any unallowed settings the relay will
ask for a change of the concerning settings.
SETTINGS
OFF LINE
Æ
È
COUNTERS
OFF LINE
Æ
In the SETTINGS menu all relay parameters can
be set. Refer to section 6.8 for a detailed
description.
In the COUNTERS menu statistical data about
the circuit breaker can be seen. Refer to section
6.14.3 for a detailed description.
È
OFF LINE
ALARM/TRIP
DATA
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Æ
È
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
In the ALARM/TRIP DATA event recordings of
the last three fault detections and the last three
DEMAND
AMMETER
OFF LINE
In the DEMAND AMMETER menu the demand
ampere meter can be read out. Refer to sections
4.22.4 and 6.14.5 for a detailed description.
Æ
È
MANUFACT.
DATA
OFF LINE
In the MANUFACTURER DATA various
information is provided, for example about the
ordering code and the serial number of the
relay. Furthermore, in this menu block a reset to
the factory settings can be initiated. Refer to
section 6.14.7 for a detailed description.
Æ
È
6.5
trips can be seen. Refer to section 6.14.4 for a
detailed description.
SETTINGS menu
The SETTINGS menu part is used for setting the
parameters of MFR 7SJ551. SETTINGS contains
7 sublevels. This description is only fully
applicable to the maximum version of the relay.
È
SETTINGS
OFF LINE
È
SETTINGS
Æ DEVICE DATA
Æ
È
SETTINGS
CHANNELS
Æ
È
SETTINGS
PROTECTIONS
Æ
In the DEVICE DATA information about the
protected component is programmed, to match
the protection functions to the component data.
Refer to section 6.6 for a detailed description.
In the CHANNELS menu the operator
determines which current and voltage inputs are
used and matches them to primary values. Refer
to section 6.7 for a detailed description.
In the PROTECTIONS menu all protection
functions are set. Refer to section 6.8 for a
detailed description.
È
SETTINGS
TRANSIENT
DATA
Æ
In the TRANSIENT DATA the operator
determines how the fault recording is started.
Refer to section 6.9 for a detailed description.
È
SETTINGS
REAL TIME
CLOCK
Æ
In the REAL TIME CLOCK menu date and time
can be altered. Furthermore, time
synchronisation can be activated here. Refer to
section 6.10 for a detailed description.
Æ
In the MARSHALLING menu all inputs, outputs
and freely programmable LED indicators can be
designated to all protective input and output
signals. Refer to section 6.11 for a detailed
description.
È
SETTINGS
MARSHALLING
È
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
SETTINGS
SERIAL.COMM.
6.6
Æ
In the SERIAL COMMUNICATION menu the
serial communication facility can be matched to
the connected personal computer or station
management system. Refer to section 6.12 for
a detailed description.
Settings for DEVICE DATA
In the DEVICE DATA information about the
protected component is programmed, to match
the protection functions to the component data.
È
SETTINGS
DEVICE DATA
LINE
Æ FREQUENCY
fn
[Hz]
50
fn
60
Nominal frequency of the protected device.
50 Hz or 60 Hz
[Hz]
È
FULL LOAD
I-flc [In]
1.00
È
Full load current of the protected device.
Setting range:
0.05 to 28 ⋅ In
The rated current provided by the manufacturer
of the protected component should be filled in
here. The full load current value is used by MFR
7SJ551 for the thermal overload protection and
the start inhibit function.
The full load current is converted in accordance
with the current transformers and expressed in
the secondary current value of the current input
transformers (1 A or 5 A).
Example 1
A device with a nominal full load current of 88
A and a current transformer with a ratio of 100
: 1 needs an Iflc value of 1/100 x 88 = 0.88 ⋅ In
(this current can be connected to the 1 A
current input).
Example 2
A device with a nominal full load current of 88
A and a current transformer with a ratio of 100
: 5 will cause a current of 5/100 x 88 = 4.4 A.
This current should be connected to the 5 A
current input and the setting value is again
4.4/5 = 0.88 ⋅ In.
DEVICE TYPE:
NONROTATING
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ROTATING
È
G88700-C3527-07-7600
MFR 7SJ551
Type of the protected device.
NON-ROTATING or ROTATING
Operating instructions
Choose NON-ROTATING for transformers, blowout coils, cables, overhead lines and capacitor
banks. Choose ROTATING for motors.
Depending on the device type two different menu
parts will appear.
G88700-C3527-07-7600
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MFR 7SJ551
6.6.1
Operating instructions
Non-rotating device
For a non-rotating device only the overload
factor and the type of the temperature sensors
have to be set.
È
NON-ROTATING
k
1.10
Overload factor
Setting range:
È
1 to 1.5
The overload factor determines the maximum
allowable continuous current (k x Iflc).
In most cases the overload factor is mentioned in
the data of the manufacturer. If k = 1.05 it
means that a current of 1.05 x Iflc will not cause
a thermal overload.
TEMPERATURE
SENS
TYPE:
Pt
100
6.6.2
TYPE:
100
Ni
TYPE:
120
NI
Temperature sensor type
Pt 100 or Ni 100 or Ni 120
This menu part determines the kind of
temperature sensor used for performing the
ambient temperature biasing and the
overtemperature protection.
Rotating device
For motors several motor data have to be set.
Together with the full load current these data
are used to determine if the motor is standing
still, starting or running; furthermore these
settings are used by the rotor and stator thermal
overload functions.
È
DEVICE TYPE:
ROTATING
È
MOTOR
Inoload[In]
.100
È
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No-load current
Setting range:
0.05 to 1 ⋅ In
The motor will be regarded stopped when all the
phase currents are below the setpoint value Inoload.
In most cases the no-load current value is
provided by the motor manufacturer. The motor
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
status ‘STOPPED’ is used by MFR 7SJ551 for
several functions (for example for ‘Curve switch’
and ‘Block’).
Permissible start-up current
MOTOR
I-start[In]
4.00
È
Setting range:
0.05 to 28 ⋅ In
Istart must be set higher than Iflc.
MFR 7SJ551 uses Istart for the calculation of τrotor.
In most cases the permissible start-up current
value is provided by the motor manufacturer.
Often values of Istart are given for 80% and 100%
rated motor voltage. For setting the manufacturer
value of Istart for 100% rated motor voltage is
preferable, even if the actual motor start-up
current is different.
MOTOR
t-start [s]
10.0
È
Permissible start-up time
Setting range:
1 to 200 s
MFR 7SJ551 uses tstart for the calculation of τrotor.
In most cases the permissible start-up time is
provided by the motor manufacturer. Often
values of tstart are given for 80% and 100% rated
motor voltage. For setting the manufacturer value
of tstart for 100% rated motor voltage is
preferable, even if the actual motor start-up time
is different.
MOTOR
k-stat
1.10
È
Overload factor stator
Setting range:
1 to 1.5
The stator overload factor determines the
maximum allowable continuous stator current
(kstat x Iflc).
In most cases the stator overload factor is
mentioned in the data of the manufacturer. If kstat
= 1.10 it means that a current of 1.10 x Iflc will
not cause a stator thermal overload.
For most motors a minimum setting level for kstat
is 1.05.
MOTOR
k-inv
5.00
È
Unbalance factor
Setting range:
0 to 10
The unbalance factor represents the extra
warming up of the rotor due to asymmetric
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
currents. Practical values can be calculated out
of:
k inv = 230 ⋅
I2flc
I2start
Permissible number of starts from warm
condition.
MOTOR
n-warm
2
Setting range:
È
1 to 15
In most cases the permissible number of starts
from warm condition is provided by the motor
manufacturer.
Permissible number of starts from cold
condition.
MOTOR
n-cold
3
È
Setting range:
1 to 15
In most cases the permissible number of starts
from cold condition is provided by the motor
manufacturer.
Temperature sensor type.
TEMPERATURE
SENS
TYPE:
Pt
100
6.7
TYPE:
100
Ni
TYPE:
120
NI
Pt 100 or Ni 100 or Ni 120
This menu part determines the kind of
temperature sensor used for performing the
ambient temperature biasing and the
overtemperature protection.
Settings for CHANNELS
In the CHANNELS menu measuring inputs can
be selected. Here primary and secondary values
are linked together. Three submenus, ‘PHASE
CIRCUITS’, ‘EARTH CIRCUIT’ and ‘VOLTAGE
CIRCUIT’ must be entered.
È
SETTINGS
CHANNELS
CHANNELS
Æ PHASE
CIRCUITS
PHASE
Æ CIRCUITS
L1:
DISABLED
CIRCUITS
L2:
DISABLED
L2:
ENABLED
È
L1:
ENABLED
È
PHASE
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G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Beginning of the submenu CHANNELS and of the
submenu PHASE CIRCUITS
Disabling measuring of input phase current IL1
Enabling measuring of input phase current IL1
Disabling measuring of input phase current IL2
Enabling measuring of input phase current IL2
PHASE
CIRCUITS
L3:
DISABLED
L3:
ENABLED
Maximum three and minimum two phases must
be enabled to make processing of measured input
currents possible.
È
PHASE
CIRCUITS
In:
[A]
1
In:
5
Disabling measuring of input phase current IL3
Enabling measuring of input phase current IL3
[A]
È
PHASE
CIRCUITS CTRATIO
1
Rated current
1 A or 5 A
This is the rated secondary current transformer
current.
Current transformer ratio.
Setting range:
1 to 9999
È
Be aware that this is a ratio, not the primary
current transformer current.
Example
For a 500 : 5 current transformer the rated
current must be set to 5 A and the current
transformer ratio must be set to 100.
PHASE
CIRCUITS
Imax [In]
28
Imax
7
[In]
Imax
14
[In]
È
G88700-C3527-07-7600
Full scale phase current
7 A or 14 A or 28 A
The full scale phase current is of influence on
the accuracy of the measured current values.
As the sampling of the current amplitude is
discrete, the available number of sampling steps
is distributed over the programmed full scale.
This means the accuracy is highest for a full
scale of 7 A and a factor 4 lower for 28 A. In
practice, this has no significant effect on the
performance of the protection functions, but is
noticeable only for fault recording momentary
values. Set the full scale phase current higher
than the expected maximum current. (For
currents higher than the programmed full scale
phase current MFR 7SJ551 uses the maximum
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
value instead. As the relay works on the ground
harmonic only, the work value will be lower
than the real value.)
If the programmed full scale phase current is 7
A (RMS), a phase current of 10 A (RMS) will be
cut off when the sinus momentary value
reaches √2 ⋅ 7 A.
Example
Beginning of the submenu EARTH CIRCUIT
CHANNELS
EARTH CIRCUIT
EARTH CIRCUIT
Æ e:
ENABLED
e:
DISABLED
Disabling measuring of input earth current Ie
Enabling measuring of input earth current Ie
È
EARTH CIRCUIT
Ien
[A]
1
Ien
5
[A]
Rated earth current
1 A or 5 A
This is the rated secondary current transformer
earth current.
È
For ordering types MFR 7SJ5513 and MFR
7SJ5514 (sensitive earth current) only 1 A is
possible.
EARTH CIRCUIT
CT-RATIO
1
È
EARTH CIRCUIT
Iemax [In]
28
Iemax [In]
7
Iemax [In]
14
Earth current transformer ratio
Setting range:
1 to 9999
Full scale earth current
7 A or 14 A or 28 A
current)
0.35 A or 0.7 A or 1.4 A
current)
(regular earth
(sensitive earth
È
Set the full scale earth current higher than the
expected maximum earth current.
CHANNELS
VOLTAGE
CIRCUIT
Beginning of the submenu VOLTAGE CIRCUIT
VOLTAGE
Æ CIRCUIT
Uin:
ENABLED
Disabling measuring of input voltage Uin
Enabling measuring of input voltage Uin
Uin:
DISABLED
È
Voltage circuit type
VOLTAGE
CIRCUIT
U select:
Uo
U0 or Uln or UPh
U select:
ln
U-
U select:
Ph
U-
È
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Here residual voltage, line-to-line voltage or phase
to earth voltage can be selected. These are
merely text indications, no functional difference
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
is made by the relay.
VOLTAGE
CIRCUIT
Un
[V]
100
Un
110
100 V or 110 V
[V]
È
VOLTAGE
CIRCUIT
VT-RATIO
1
G88700-C3527-07-7600
Rated voltage
Voltage transformer ratio
Setting range:
1 to 9999
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MFR 7SJ551
Operating instructions
6.8
Settings for
PROTECTIONS
In the PROTECTIONS menu all protection
functions are set. PROTECTIONS contains 16
sublevels. This description is only fully applicable
to the maximum version of the relay.
È
SETTINGS
PROTECTIONS
È
PROTECTION
Æ THERM.OVERLOA
D
È
PROTECTION
OVERTEMPERATU
RE
Æ
Æ
È
PROTECTION
UNDERCURRENT
Æ
È
PROTECTION
LOW SET O.C.
Æ
È
PROTECTION
HIGH SET O.C.
Æ
È
PROTECTION
UNBALANCE
Æ
È
PROTECTION
DIR.
EARTHFAULT
Æ
È
PROTECTION
LOCKED ROTOR
Æ
È
PROTECTION
ZERO SPEED
Æ
È
PROTECTION
UNDERVOLTAGE
Æ
È
PROTECTION
OVERVOLTAGE
Æ
È
PROTECTION
BF TRIP
Æ
È
PROTECTION
CURVE SWITCH
Æ
È
PROTECTION
BLOCK
Æ
È
PROTECTION
EXT. CMD
Æ
È
PROTECTION
CB POSITION
Æ
G88700-C3527-07-7600
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MFR 7SJ551
¡Error! Argumento de modificador desconocido.
Operating instructions
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
6.8.1
THERMAL OVERLOAD protection
6.8.1.1
Thermal overload protection for rotating objects
For motors MFR 7SJ551 uses different thermal
models for the rotor and the stator.
Most parameters for the rotor thermal overload
protection are set already in DEVICE DATA.
The parameters set in the submenu THERMAL
OVERLOAD (ROTATING OBJECTS) are
combined with the motor manufacturer data as
set in the DEVICE DATA menu to form the rotor
and stator thermal overload models.
Most parameters for the stator thermal overload
protection are programmed in the submenu
THERMAL OVERLOAD described here.
È
PROTECTION
THERMAL
THERM.OVERLOA Æ OVERLOAD
D
ENABLED
DISABLED
È
Beginning of the submenu THERMAL OVERLOAD
Enabling the thermal overload protection
Disabling the thermal overload protection
DISABLED
Disabling the AMBIENT TEMPERATURE BIASING
Enabling the AMBIENT TEMPERATURE BIASING.
ENABLED
Refer to section 6.8.2 for a detailed description.
AMBIENT TEMP.
È
THERMAL
OVERLOAD
τ1,stat [s]
100
È
THERMAL
OVERLOAD
τ2,stat [s]
200
È
THERMAL
OVERLOAD
p-weight
.500
Thermal time constants stator
Setting range:
1 s to 999 min
MFR 7SJ551 uses two time constants for the
stator thermal overload protection. Each time
constant determines an exponential curve. These
two curves are added up, weighted by a
weighing factor pweight.
Weighing factor
Setting range:
0 to 1
È
The parameters τ1,stat, τ2,stat and pweight are set
according to the stator thermal withstand curve
supplied by the motor manufacturer. Use the
operating and evaluation software program
‘Communication Utility MFR 7SJ551’ to calculate
the three parameters out of three current-time
points.
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
Example
t
1.06 x Iflc
3000 s
1.77 x Iflc
180 s
3 x Iflc
50 s
kstator x Iflc
I
Figure 6.3
For the three current-time points of figure 6.3
(kstat = 1.05, preload = 0%) ‘Communication
Utility MFR 7SJ551’ calculates:
τ1,stat
= 861
s
τ2,stat
= 195
s
pweight = 0.61
With no thermal withstand curve (or three
operating points) available it makes no sense to
use all three parameters τ1,stat, τ2,stat and pweight.
Just set pweight to 1; then only τ1 is effective. To
set τ1,stat only one operating point is needed
(besides the stator overload factor kstat).
Example
Only one operation point is available:
if the current step response I is 1.5 x Iflc, the
motor has to be tripped in ttrip = 20 minutes (cold
condition).
Then the formula for the tripping time (refer to
section 4.2.3) changes to:
⎛
⎞
I2
⎟
t trip = τ1,stat ⋅ ln⎜⎜ 2
2 2 ⎟
⎝ I − k stat ⋅ I flc ⎠
Filling in all known values leads to τ1,stat =26
minutes.
THERMAL
OVERLOAD
c-stop,stat
2.00
Cooling-down factor stator
Setting range:
1 to 10
È
THERMAL
OVERLOAD
c-stop,rot
2.00
Cooling-down factor rotor
Setting range:
1 to 10
È
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
When the motor is stopped it begins to cool
down. Cooling down from an attained
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
temperature generally lasts longer than warming
up to this temperature. How many times longer
can be set with these factors. In most cases the
cooling down factors are provided by the motor
manufacturer.
THERMAL
OVERLOAD
θ-warn [%]
25.0
È
Warning level stator thermal overload protection
Setting range:
0 % to 95 %
By setting this warning level a pre-alarm will be
given to enable the network operator to
disconnect load from the electric network.
Set the warning level in accordance with the
normal load current. For a continuous load
current I smaller than kstat x Iflc the thermal
reserve will eventually attain an equilibrium
value:
k2 ⋅ I2 − I2
θth(t = ∞) = stat2 flc 2
⋅ 100%
kstat ⋅ Iflc
The warning level must be set lower than this
equilibrium value, to be sure there will be a
warning for overload only.
For I = Iflc the formula changes to:
θ th (t = ∞) =
k2 − 1
k2
⋅ 100%
Example
The normal load of a motor is full load current.
kstat = 1.05. The equilibrium value of the thermal
reserve will be 9.3 %. The warning level is set to
5 %.
START INHIBIT
DISABLED
ENABLED
¡Error! Argumento de modificador desconocido.
Disabling the start inhibit function
Enabling the start inhibit function
Refer to section 6.8.3 for a detailed description.
G88700-C3527-07-7600
MFR 7SJ551
6.8.1.2
Operating instructions
Thermal overload protection for non-rotating objects
In the submenu THERMAL OVERLOAD (NONROTATING OBJECTS) parameters are set for
thermal overload protection of transformers,
blow-out coils, cables and capacitor banks.
È
THERMAL
PROTECTION
THERM.OVERLOA Æ OVERLOAD
D
ENABLED
DISABLED
È
AMBIENT TEMP.
Disabling the AMBIENT TEMPERATURE BIASING
Enabling the AMBIENT TEMPERATURE BIASING
DISABLED
Refer to section 6.8.2 for a detailed description.
ENABLED
È
THERMAL
OVERLOAD
TrueRMS:
PHASE
TrueRMS:
EARTH
È
Measuring circuit for thermal overload protection
PHASE or EARTH
This menu part determines whether the phase
currents or the earth current are used for the
thermal overload protection of the device.
Choose ‘PHASE’ if the protected device is a
transformer, cable or capacitor bank. Connect
the current transformer currents to the phase
inputs of the relay.
Choose ‘EARTH’ if the protected device is a
blow-out coil. Connect the ring core transformer
to the earth current input of the relay.
THERMAL
OVERLOAD
τ1
[s]
200
È
THERMAL
OVERLOAD
τ2
[s]
200
È
Thermal time constants stator
Setting range:
1 s to 999 min
MFR 7SJ551 uses two time constants for the
thermal overload protection of non-rotating
objects. Each time constant determines an
exponential curve. These two curves are added
up, weighted by a weighing factor pweight.
Weighing factor
THERMAL
OVERLOAD
p-weight
.500
È
G88700-C3527-07-7600
Setting range:
0 to 1
The parameters τ1, τ2 and pweight are set according
to the thermal withstand curve supplied by the
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
manufacturer of the network component. Use the
operating and evaluation software program
‘Communication Utility MFR 7SJ551’ to calculate
the three parameters out of three current-time
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
points. Refer to the preceding paragraph for an
example of how to calculate τ1, τ2 and pweight with
this program.
With no thermal withstand curve (or three
operating points) available it makes no sense to
use all three parameters τ1, τ2 and pweight. Just set
pweight to 1; then only τ1 is effective. To set τ1
only one operating point is needed (besides the
stator overload factor kstat). Refer to the
preceding paragraph for an example of how to
calculate τ1 in this situation.
THERMAL
OVERLOAD
τ-adj
ENABLED
Enabling the adjustment of the time constants
Disabling the adjustment of the time constants
τ-adj
DISABLED
Adjusting factor
È
THERMAL
OVERLOAD
c-adj
2.00
È
Setting range:
0.01 to 10
When the network component is switched off it
begins to cool down. Cooling down from an
attained temperature can last longer than
warming up to this temperature, for example
when the cooling pump of a cable is switched
off. Also, the cooling pump can break down
while the cable is warming up. In this case the
warming-up goes faster.
How many times shorter or longer warming-up or
cooling down takes, can be set with the
adjusting factor. By energizing the binary τadj
input (via a control system or by hand) the time
constants are multiplied each with the cadj factor.
THERMAL
OVERLOAD
θ-warn [%]
25.0
Warning level thermal overload protection for
non-rotating objects
Setting range:
0 to 95 %
By setting this warning level a pre-alarm will be
given to enable the network operator to
disconnect load from the electric network.
Set the warning level in accordance with the
normal load current. For a continuous load
current I smaller than k x Iflc the thermal reserve
will eventually attain an equilibrium value:
θth(t = ∞) =
G88700-C3527-07-7600
k2 ⋅ I2flc − I2
⋅ 100%
k2 ⋅ I2flc
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
The warning level must be set lower than this
equilibrium value, to be sure there will be a
warning for overload only.
For I = Iflc the formula changes to:
θ th (t = ∞) =
k2 − 1
k2
⋅ 100%
Example
The normal load of a network component is full
load current. k = 1.05. The equilibrium value of
the thermal reserve will be 9.3 %. The warning
level is set to 5 %.
6.8.2
AMBIENT TEMPERATURE BIASING (optional)
The AMBIENT TEMPERATURE BIASING menu is
a submenu of the THERMAL OVERLOAD menu.
With these parameters MFR 7SJ551 adjusts the
values in the thermal reserve buffers according
È
THERMAL
PROTECTION
THERM.OVERLOA Æ OVERLOAD
D
ENABLED
DISABLED
È
AMBIENT TEMP.
to the actual ambient temperature. This menu
part is only applicable in relays equipped with an
interface module containing temperature sensor
connectors.
Beginning of the submenu AMBIENT
TEMPERATURE BIASING
Enabling the ambient temperature biasing
Disabling the ambient temperature biasing
ENABLED
DISABLED
È
AMBIENT TEMP.
T-max [°C]
****
È
Maximum ambient temperature
Setting range:
0 to 200 °C
This menu part determines the maximum
allowable temperature of the used isolation
material of the device (and not the expected
maximum environment temperature!). Set this
value to 120 °C if isolation is in accordance with
class B, and to 140 °C for class F.
Nominal ambient temperature
AMBIENT TEMP.
T-min [°C]
****
Setting range:
0 to 200 °C
È
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
This menu part determines the nominal environment temperature (and not the minimum allowed
environment temperature!). In most cases this
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
value is set to 40 °C (refer to manufacturer data).
Tmax must always be higher than Tmin.
AMBIENT TEMP.
INPUT SENSOR
1
INPUT SENSOR
2
Input sensor number
Choose the number of the input sensor that is
measuring the ambient temperature.
INPUT SENSOR
8
6.8.3
START INHIBIT
The START INHIBIT menu is a submenu of the
THERMAL OVERLOAD menu. With the
parameters set in this menu, MFR 7SJ551
inhibits starting of the motor until the motor has
regained sufficient thermal reserve.
È
THERMAL
PROTECTION
THERM.OVERLOA Æ OVERLOAD
D
ENABLED
È
È
È
È
È
È
È
È
START INHIBIT
ENABLED
Beginning of the submenu START INHIBIT
Enabling the start inhibit function
Disabling the start inhibit function
DISABLED
È
START INHIBIT
t-inh
[s]
5.00
È
Start inhibit release extension time
Setting range:
0 s to 166 min
This is an additional release time of the start
inhibit output relay after the thermal reserve has
reached the threshold value. With this parameter
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
the total time the start inhibit output prevents the
motor from starting is extended.
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
Example
A motor has been tripped upon rotor thermal
overload. The stator thermal reserve is above the
stator inhibit level. The rotor warming-up time
constant is 200 s. The rotor inhibit level is 30%
(refer to sections 3.* and 4.* for calculations).
The rotor cooling down factor is 2. According to
the manufacturer data a start has to be inhibited
for 10 minutes after trip. How long must the
start inhibit release extension time be set? As the
load current is zero and the preload current is
krotor x Iflc, the formula for the rotor thermal
reserve changes to:
θ th,rotor (t) = (1 − e
−
t
cstop,rot ⋅τ rotor
) ⋅ 100% .
After -400 x ln 0.7 = 143 s the rotor thermal
reserve will reach 30%. So tinh must be set to
10 x 60 - 143 = 457 s.
START INHIBIT
θ-stator[%]
50.0
È
Stator start inhibit level
Setting range:
0 to 100%
The stator start inhibit level only works upon the
stator thermal reserve buffer. Be aware that the
start inhibit function works for both rotor thermal
reserve and stator thermal reserve buffers. Both
thermal reserves must exceed the release
thresholds before the start inhibit output is
released. (The rotor start inhibit level cannot be
set separately from the stator start inhibit level; it
is calculated by the relay as described in section
4.4.)
Set the stator inhibit level in accordance with
motor manufacturer recommendations. The time
needed for reaching the inhibit level after trip, is
related to the stator start inhibit level according
to the following formula.
θ stat = (1 − (pweight ⋅ e
+(1 − pweight ) ⋅ e
−
t release
cstop,stat τ1,stat
t release
−
cstop,stat τ2,stat
+
)) ⋅ 100%
Example 1
For a motor with τ1,stat = 100 s, τ2,stat = 200 s,
pweight = 0.5 and cstop,stat = 2 the manufacturer
recommends to inhibit a start for 5 minutes after
stator overload trip. How must the stator start
inhibit level be set? Filling in the release time
gives a stator start inhibit level of 54.1%. (The
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
start inhibit release extension time can be set to
0 s.)
Example 2
For a motor with τ1,stat = 100 s, τ2,stat = 200 s,
pweight = 0.5 and cstop,stat = 2 the stator start
inhibit level is set to 50% and the start inhibit
release extension time is set to 0 s. How long
does it take to release a start? Filling in different
release times:
release time stator start inhibit level
275 s
49.6%
276 s
49.8%
277 s
50.0%
278 s
50.1%
279 s
50.3%
280 s
50.5%
gives a release time of 277 s.
EMERG.
RESTART
Enabling the emergency restart function
Disabling the emergency restart function
DISABLED
ENABLED
6.8.4
When the start inhibit function is enabled, here
the emergency restart function can be activated.
EMERGENCY RESTART
The EMERGENCY RESTART menu is a submenu
of the START INHIBIT menu. With setting the
EMERGENCY RESTART parameter the start
inhibit can be overruled.
È
THERMAL
PROTECTION
THERM.OVERLOA Æ OVERLOAD
D
ENABLED
È
È
È
È
È
È
È
È
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
È
START INHIBIT
ENABLED
È
È
È
EMERG.
RESTART
ENABLED
DISABLED
6.8.5
Beginning of the submenu EMERGENCY
RESTART
Enabling the emergency restart function
Disabling the emergency restart function
No further parameters have to be set. To
overrule the start inhibit the binary emergency
restart input has to be energized. Then the
thermal reserve buffers will be reset to 100%.
OVERTEMPERATURE protection (optional)
For OVERTEMPERATURE PROTECTION the
relay has to be equipped with an interface
module containing temperature sensor
connectors. Two types RTD interface modules
are available: with two or with eight
È
OVERTEMPERATU
PROTECTION
OVERTEMPERATU Æ RE
RE
ENABLED
temperature sensor con-nec-tors. Temperature
sensor inputs that are not connected to a
temperature sensor should be closed with a
resistor (50 - 100 Ω) to fix the display value.
Beginning of the submenu OVERTEMPERATURE.
Enabling the overtemperature protection.
Disabling the overtemperature protection.
DISABLED
È
OVERTEMPERATU
RE
ALARM 1 [°C]
***
È
OVERTEMPERATU
RE
TRIP 1 [°C]
***
È
Overtemperature alarm level
Setting range:
0 to 200 °C
Overtemperature trip level
Setting range:
0 to 200 °C
For each temperature sensor an alarm pick-up
and a trip pick-up can be set individually (only
integers). Unused temperature sensor pick-ups
should be set to 999 °C to prevent unwanted
pick-up. The trip value must be set higher than
the alarm value.
È
OVERTEMPERATU
RE
ALARM 8 [°C]
***
È
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
OVERTEMPERATU
RE
TRIP 8 [°C]
***
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
6.8.6
Operating instructions
UNDERCURRENT protection
UNDERCURRENT PROTECTION can be applied
to all network components. For motors the
È
PROTECTION
UNDERCURRENT
UNDERCURRENT
Æ
ENABLED
function needs one parameter more (tbypass) than
for non-rotating objects.
Beginning of the submenu UNDERCURRENT
Enabling the undercurrent protection
Disabling the undercurrent protection
DISABLED
È
UNDERCURRENT
t-bypass[s]
5.00
È
Bypass time
Setting range:
0 to 100 s
The undercurrent bypass time is applicable for
motors only. The bypass time is started at the
moment the motor status changes from ‘start’ to
‘running’. During the bypass time the
undercurrent protection function is inactive.
UNDERCURRENT
I<
[In]
.500
È
Undercurrent pick-up
Setting range:
0.05 to 28 ⋅ In
For motors the pick-up value must be set higher
than the no-load current. Pick-up occurs in case
of a loss of or decrease in motor load. Examples
of such situations are: loss of suction of pumps,
loss of airflow for fans or a broken belt for
conveyors.
For capacitor banks the pick-up value must be
set minimum to (0.05 ⋅ In), to be sure the relay
does not pick up if there is remaining capacitive
current.
UNDERCURRENT
tI<
[s]
3.00
¡Error! Argumento de modificador desconocido.
Undercurrent delay time
Setting range:
0 s to 166 min
G88700-C3527-07-7600
MFR 7SJ551
6.8.7
Operating instructions
LOW SET OVERCURRENT protection
For low set overcurrent protection, MFR
7SJ551 distinguishes between
− phase fault overcurrent
− earth fault overcurrent.
The possible characteristics for low set phase
and earth fault overcurrent protection are:
− definite time overcurrent
− inverse time overcurrent
− custom curve overcurrent.
È
PROTECTION
LOW SET O.C.
LOW SET O.C.
Æ PHASE:
ENABLED
PHASE:
DISABLED
È
LOW SET O.C.
Ph
CURVE 1
È
LS O.C.Ph
CURVE1
CHAR:
DEFINITE
CHAR:NORMAL
INV
CHAR:
INV
VERY
CHAR:
INV
EXTR
Two different characteristics for phase
overcurrent protection and two different
characteristics for earth fault overcurrent
protection can be programmed. During operation
the CURVE SWITCH function determines which
of the two is effective. Refer to section 6.8.16
for a detailed description.
Beginning of the submenu LOW SET
OVERCURRENT
Enabling the low set phase fault overcurrent
protection
Disabling the low set phase fault overcurrent
protection
Choose the type of phase fault overcurrent
characteristic for CURVE 1.
DEFINITE
Refer to section 6.8.7.1
NORMAL INVERSE
VERY INVERSE
EXTREMELY INVERSE
Refer to section 6.8.7.3
CUSTOM CURVE
Refer to section 6.8.7.5
CHAR:
CUSTOM
È
È
È
LOW SET O.C.
Ph
CURVE 2
È
The same procedure is followed for setting phase
fault CURVE 2.
È
È
È
LOW SET O.C.
EARTH:
ENABLED
EARTH:
DISABLED
È
G88700-C3527-07-7600
Enabling the low set earth fault overcurrent
protection
Disabling the low set earth fault overcurrent
protection
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
LOW SET O.C.
e
CURVE 1
È
LS O.C. e
CURVE1
CHAR:
DEFINITE
CHAR:NORMAL
INV
CHAR:
INV
VERY
CHAR:
INV
EXTR
CHAR:
EARTH
LT
CHAR:
TIME
Choose the type of earth fault overcurrent
characteristic for CURVE 1.
DEFINITE
Refer to section
6.8.7.2
NORMAL INVERSE
VERY INVERSE
EXTREMELY INVERSE
LONG TIME EARTH FAULT
RESIDUAL DEPENDANT TIME
CUSTOM CURVE
Refer to section
6.8.7.4
Refer to section
6.8.7.5
RD
CHAR:
CUSTOM
È
È
È
È
LOW SET O.C.
e
CURVE 2
È
The same procedure is followed for setting earth
fault CURVE 2.
È
È
6.8.7.1
Definite time phase fault overcurrent protection
È
PROTECTION
LOW SET O.C.
LOW SET O.C.
Æ PHASE:
ENABLED
PHASE:
DISABLED
È
LOW SET O.C.
Ph
CURVE 1
È
Beginning of the submenu LOW SET
OVERCURRENT PHASE
Enabling the low set phase fault overcurrent
protection
Disabling the low set phase fault overcurrent
protection
Beginning of the settings for phase fault CURVE
1. If the CURVE SWITCH function is disabled,
this menu line will not appear.
È
LS O.C.Ph
CURVE1
CHAR:
DEFINITE
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Beginning of the phase fault DEFINITE TIME
overcurrent settings
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
LS O.C.Ph
CURVE1
I>
[In]
1.50
È
Pick-up value of the phase fault overcurrent
stage I>
Setting range:
0.05 to 28 ⋅ In
The maximum load current determines the setting
of the overcurrent stage I>. Pick-up on overload
must be excluded since the low set overcurrent is
a short-circuit protection with adequate short
tripping time. Therefore the overcurrent stage is
set to 120% for feeder lines, and 150% for
transformers or motors referred to maximum
overload current.
LS O.C.Ph
CURVE1
tI>
[s]
5.00
Trip time delay for the overcurrent stage I>
Setting range:
0 s to 166 min
È
The time delay tI> depends on the grading plan
for the network. For modern circuit breakers
minimum 0.3 s time difference between two
grading levels can be used. Use 0.5 s for older
circuit breakers. The setting times are pure
delay times which do not include the relay
operating time.
È
È
LOW SET O.C.
Ph
CURVE 2
È
For curve 2 an alternative characteristic or an
alternative pick-up value or delay time can be set.
CURVE 2 is available only if the CURVE SWITCH
function is activated.
For motor protection it is beneficial to set the
CURVE SWITCH function in the mode STATUS.
In this case, for high speed clearing of motor
phase faults the following conditions must be
fulfilled for the setting of the pick-up value I> of
CURVE 2:
− the minimum pick-up value must be greater
than 1.6 times motor locked rotor current
(maximum inrush due to asymmetry)
− the minimum pick-up value must be smaller
than the minimum short-circuit current.
Differential protection should be provided if the
above criteria are not met! In practice the
maximum pick-up current must be smaller than
circa 1/3 of the maximum occurring 3-phase
short-circuit current. Program the STATUS
mode to STOP/START; then CURVE 2 is
activated automatically when the relay
recognizes a start or stand-still.
For transformer protection CURVE 2 can be
used to lift up the pick-up value temporarily
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
during transformer inrush. To activate CURVE 2
a binary input is energized.
Refer to section 6.8.16 for a more detailed
description of the CURVE SWITCH function.
6.8.7.2
Definite time earth fault overcurrent protection
È
PROTECTION
LOW SET O.C.
LOW SET O.C.
Æ PHASE:
DISABLED
È
LOW SET O.C.
EARTH:
ENABLED
EARTH:
DISABLED
Beginning of the submenu LOW SET
OVERCURRENT EARTH
Enabling the low set earth fault overcurrent
protection
Disabling the low set earth fault overcurrent
protection
È
LOW SET O.C.
e
CURVE 1
È
LS O.C. e
CURVE1
CHAR:
DEFINITE
Beginning of the settings for earth fault CURVE
1. If the CURVE SWITCH function is disabled,
this menu line will not appear.
Beginning of the earth fault DEFINITE TIME
overcurrent settings
È
LS O.C. e
CURVE1
Ie>
[In]
.500
È
Pick-up value of the earth fault overcurrent
stage Ie>
Setting range:
0.05 to 28 ⋅ In for regular earth current detection
0.003 to 1.4 ⋅ In for sensitive earth current
detection
The minimum earth fault current determines the
setting of the overcurrent stage Ie>.
With DIRECTIONAL EARTHFAULT PROTECTION
enabled, the denomination of the pick-up value
changes to Iφ>.
LS O.C. e
CURVE1
tIe>
[s]
5.00
Trip time delay for the overcurrent stage Ie>
Setting range:
0 s to 166 min
È
The time delay tIe> depends on the grading plan
for the network which can be separate for earth
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
faults. For modern circuit breakers minimum 0.3
s time difference between two grading levels
can be used. Use 0.5 s for older circuit
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
breakers. The setting times are pure delay times
which do not include the relay operating time.
With DIRECTIONAL EARTHFAULT PROTECTION
enabled, the denomination of the time delay
changes to tIφ>.
È
È
LOW SET O.C.
e
CURVE 2
For curve 2 an alternative characteristic or an
alternative pick-up value or delay time can be set.
CURVE 2 is available only if the CURVE SWITCH
function is activated.
È
6.8.7.3
Inverse time phase fault overcurrent protection
È
PROTECTION
LOW SET O.C.
LOW SET O.C.
Æ PHASE:
ENABLED
Beginning of the submenu LOW SET
OVERCURRENT PHASE
Enabling the low set phase fault overcurrent
protection
Disabling the low set phase fault overcurrent
protection
PHASE:
DISABLED
È
LOW SET O.C.
Ph
CURVE 1
È
LS O.C.Ph
CURVE1
CHAR:NORMAL
INV
CHAR:
INV
VERY
CHAR:
INV
EXTR
Beginning of the settings for phase fault CURVE
1. If the CURVE SWITCH function is disabled,
this menu line will not appear.
Type of INVERSE characteristic for CURVE 1
NORMAL INVERSE
VERY INVERSE
EXTREMELY INVERSE
CHAR:
...
CHAR:
...
È
LS O.C.Ph
CURVE1
Ip
[In]
1.50
È
time lag according to
IEC 255-3, type A
time lag according to
IEC 255-3, type B
time lag according to
IEC 255-3, type C.
A choice can be made between three tripping
characteristics defined in IEC 255-3.
Pick-up value of the phase fault overcurrent
stage Ip
Setting range:
0.05 to 28 ⋅ In
tp
1.00
LS O.C.Ph
CURVE1
G88700-C3527-07-7600
È
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MFR 7SJ551
Operating instructions
Setting range:
Time multiplier for the overcurrent stage I
0 to 10
p
È
È
LOW SET O.C.
Ph
CURVE 2
For curve 2 an alternative characteristic or an
alternative pick-up value or delay time can be set.
CURVE 2 is available only if the CURVE SWITCH
function is activated.
È
6.8.7.4
Inverse time earth fault overcurrent protection
È
PROTECTION
LOW SET O.C.
LOW SET O.C.
Æ PHASE:
DISABLED
È
LOW SET O.C.
EARTH:
ENABLED
EARTH:
DISABLED
Beginning of the submenu LOW SET
OVERCURRENT EARTH
Enabling the low set earth fault overcurrent
protection
Disabling the low set earth fault overcurrent
protection
È
LOW SET O.C.
e
CURVE 1
È
Beginning of the settings for earth fault CURVE
1. If the CURVE SWITCH function is disabled,
this menu line will not appear.
Type of INVERSE characteristic for CURVE 1
LS O.C.Ph
CURVE1
CHAR:NORMAL
INV
NORMAL INVERSE
time lag according to
IEC 255-3, type A
time lag according to
IEC 255-3, type B
time lag according to
IEC 255-3, type C.
CHAR:
INV
VERY
VERY INVERSE
CHAR:
INV
EXTR
EXTREMELY INVERSE
CHAR:
EARTH
LT
LONG TIME EARTH FAULT
RESIDUAL DEPENDANT TIME
CHAR:
TIME
RD
CHAR:
...
CHAR:
...
È
LS O.C. e
CURVE1
Iep
[In]
.500
È
¡Error! Argumento de modificador desconocido.
A choice can be made between three tripping
characteristics defined in IEC 255-3 and two
additional characteristics.
Pick-up value of the earth fault overcurrent
stage Iep
Setting range:
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
0.05 to 28 ⋅ In for regular earth current detection
0.003 to 1.4 ⋅ In for sensitive earth current
detection
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
With DIRECTIONAL EARTHFAULT PROTECTION
enabled, the denomination of the pick-up value
changes to Iφp. For the RESIDUAL DEPENDANT
TIME curve the denomination of the pick-up value
changes to Ie>.
LS O.C. e
CURVE1
tep
1.00
Time multiplier for the overcurrent stage Iep
Setting range:
0 to 10
With DIRECTIONAL EARTHFAULT PROTECTION
enabled, the denomination of the time multiplier
changes to tφp.
È
È
LOW SET O.C.
Ph
CURVE 2
For curve 2 an alternative characteristic or an
alternative pick-up value or delay time can be set.
CURVE 2 is available only if the CURVE SWITCH
function is activated.
È
6.8.7.5
Custom curve overcurrent protection
The description of the CUSTOM CURVE
overcurrent protection is valid for both phase
and earth fault overcurrent protection. For earth
fault overcurrent protection ‘earth’ should be
read where ‘phase’ is used.
È
PROTECTION
LOW SET O.C.
LOW SET O.C.
Æ PHASE:
ENABLED
PHASE:
DISABLED
È
LOW SET O.C.
Ph
CURVE 1
È
LS O.C.Ph
CURVE1
CHAR:
CUSTOM
Beginning of the submenu LOW SET
OVERCURRENT PHASE
Enabling the low set phase fault overcurrent
protection
Disabling the low set phase fault overcurrent
protection
Beginning of the settings for phase fault CURVE
1. If the CURVE SWITCH function is disabled,
this menu line will not appear.
Beginning of the phase fault CUSTOM CURVE
overcurrent settings
È
LS O.C.Ph
¡Error! Argumento de modificador desconocido.
CURVE1
# OF POINTS
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
15
È
Number of current-time points
Setting range:
2 to 15
Up to 15 pairs of values of current and time can
be programmed. The relay calculates
intermediate values by linear interpolation. It is
permitted to program less current-time points.
LS O.C.Ph
CURVE1
I1
[In]
1.50
È
LS O.C.Ph
CURVE1
t I1
[s]
100
È
LS O.C.Ph
CURVE1
I2
[In]
2.50
È
LS O.C.Ph
CURVE1
t I2
[s]
90
È
È
LS O.C.Ph
CURVE1
I15
[In]
25.0
È
LS O.C.Ph
CURVE1
t I15
[s]
.500
G88700-C3527-07-7600
Pick-up value of the custom curve overcurrent
stage 1
0.05 to 28 ⋅ In for regular earth current detection
0.003 to 1.4 ⋅ In for sensitive earth current
detection
Trip time delay for the custom curve overcurrent
stage 1
Setting range:
0 s to 166 min
The relay has the following preset values:
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Iphase
1.50
2.50
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.0
12.5
15.0
17.5
20.0
25.0
t
#
100
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
15.0
10.0
5.00
2.50
1.00
0.50
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Ie
0.500
0.550
0.600
0.650
0.700
0.750
0.800
0.850
0.900
0.950
1.00
1.10
1.20
1.30
1.35
t
200
150
100
90.0
80.0
70.0
60.0
50.0
40.0
30.0
25.0
20.0
15.0
10.0
5.00
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MFR 7SJ551
6.8.8
Operating instructions
HIGH SET OVERCURRENT protection
For high set overcurrent protection MFR
7SJ551 distinguishes between:
− phase fault overcurrent
− earth fault overcurrent
È
HIGH SET O.C.
PROTECTION
HIGH SET O.C. Æ PHASE:
ENABLED
PHASE:
DISABLED
È
HIGH SET O.C.
Ph
CURVE 1
È
HS O.C.Ph
CURVE1
I>>
[In]
10.0
È
Two different characteristics for phase
overcurrent protection and two different
characteristics for earth fault overcurrent
protection can be programmed. During operation
the CURVE SWITCH function determines which
of the two is effective. Refer to section 6.8.16
for a detailed description.
Beginning of the submenu HIGH SET
OVERCURRENT PHASE
Enabling the high set phase fault overcurrent
protection
Disabling the high set phase fault overcurrent
protection
Beginning of the settings for phase fault CURVE
1. If the CURVE SWITCH function is disabled,
this menu line will not appear.
Pick-up value of the phase fault overcurrent
stage I>>
Setting range:
0.05 to 28 ⋅ In
This stage is often used for current grading
before high impedances, e.g. transformers or
motors. This stage is always a definite time
stage, independent of which characteristic is set
for the low set overcurrent stage. It protects
against short-circuits taking place in this
concentrated impedance, e.g. for transformers up
I
1
to 1.5 times
⋅ flc
uK transf In c.t.
HS O.C.Ph
CURVE1
tI>>
[s]
.500
Trip time delay for the overcurrent stage I>>
Setting range:
0 s to 166 min
È
HIGH SET O.C.
Ph
CURVE 2
È
È
For curve 2 an alternative characteristic or an
alternative pick-up value or delay time can be set.
CURVE 2 is available only if the CURVE SWITCH
function is activated.
È
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
HIGH SET O.C.
EARTH:
ENABLED
Beginning of the submenu HIGH SET
OVERCURRENT EARTH
EARTH:
DISABLED
Enabling the high set earth fault overcurrent
protection
Disabling the high set earth fault overcurrent
protection
È
All further settings for the high set earth fault
overcurrent protection are similar to the settings
of the high set phase fault overcurrent
protection.
6.8.9
A further application of the high set overcurrent
protection is the reverse interlocking principle.
The I>> stage is used for rapid tripping in case of
a bus bar fault, with only a short safety time. The
low set overcurrent stage is the back-up for
faults on an outgoing feeder. The relays
protecting the outgoing feeders block the I>>
stage via the binary input when the fault is in
their protection area (refer to figure 4.20). Set
the pick-up value I>> at the same value as I> or
Ip.
UNBALANCE protection
UNBALANCE PROTECTION can be applied to all
network components. For motors the function
needs one parameter more (tbypass) than for nonrotating objects.
È
PROTECTION
UNBALANCE
UNBALANCE
Æ
ENABLED
Beginning of the submenu UNBALANCE
Enabling the unbalance protection
Disabling the unbalance protection
DISABLED
È
UNBALANCE
t-bypass[s]
1.00
È
Bypass time
Setting range:
0 to 100 s
The unbalance bypass time is applicable for
motors only. The bypass time is started at the
moment the motor status changes from
‘stopped’ to ‘start’. During the bypass time the
unbalance protection function is inactive. A
practical value is 1.0 s.
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
UNBALANCE
I2
[In]
.200
È
Unbalance pick-up
Setting range:
0.05 to 28 ⋅ In
For motors a practical setting value can be
calculated out of:
I2p =
UNBALANCE
t2p
10.0
Iflc ⋅ k2stat − 1
3
Unbalance time multiplier
Setting range:
0 to 25
For motors a practical setting value can be
calculated out of:
t 2p = τ Cu ⋅
k2stat − 1
81⋅ k2stat − 80
with tCu the thermal copper warming-up time
constant as provided by the motor
manufacturer.
6.8.10
DIRECTIONAL EARTHFAULT protection (optional)
The DIRECTIONAL EARTHFAULT protection can
be used in isolated or arc compensated
networks to detect an earth fault and to
determine the earth fault direction. Because of
its high sensitivity it is not suited for detection
of higher earth fault currents (from 1 A and
above at the relay terminals for sensitive earth
current detection). For those applications use
È
PROTECTION
DIR.
EARTHFAULT
DIR.
Æ EARTHFAULT
ENABLED
DISABLED
the relay ordering option with terminals for
regular earth current detection.
The directional earth fault protection function
uses the two-stage current time characteristic
which is set in the submenus LOW SET
OVERCURRENT EARTH and HIGH SET
OVERCURRENT EARTH.
Beginning of the submenu DIRECTIONAL
EARTHFAULT
Enabling the directional earth fault protection
Disabling the directional earth fault protection
È
CONTROL:
SINE
DIR.
EARTHFAULT
CONTROL:
COSINE
¡Error! Argumento de modificador desconocido.
È
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Measuring principle
COSINE
SINE
active power measurement
reactive power measurement
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
In isolated systems earth fault measurement
with SINE is used because the capacitive
current is decisive for the earth fault direction.
In compensated systems earth fault
measurement with COSINE is used because the
ohmic current is decisive for the earth fault
direction.
In earthed systems earth fault measurement
with COSINE is used with a correction angle of 45° because the earth current is ohmicinductive.
In electrical machines in bus-bar connection
with an isolated system, COSINE measurement
can be selected with a correction angle of
+45° because the earth current is often
composed of a capacitive component from the
system and an active component from an earth
fault load resistor.
DIR.
EARTHFAULT
U-strt [Un]
****
Displacement voltage
Setting range:
0.05 to 1.2 ⋅ Un
È
The residual voltage Ustrt initiates earth fault
detection and is one condition for release of
directional determination. Since, for earth faults
in isolated or compensated networks, the full
displacement voltage appears, the setting value
is not critical; it should lie between 30 V and 60
V. In earthed networks, the set value of the
earth voltage Ustrt can be more sensitive
(smaller); but it should not be exceeded by
operational asymmetry of the voltages of the
power system.
DIR.
EARTHFAULT
t U-strt[s]
****
Pick-up delay
Setting range:
0 s to 166 min
È
Earth fault is detected and annunciated only
when the displacement voltage has been
present for the duration tUstrt.
DIR.
EARTHFAULT
Iφ>
FORWARD
Iφ>
BACKWARD
Directional trip condition for low set earth
current stage
FORWARD or BACKWARD
È
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
DIR.
EARTHFAULT
Iφ>>
FORWARD
Iφ>>
BACKWARD
Directional trip condition for high set earth
current stage
FORWARD or BACKWARD
È
DIR.
EARTHFAULT
φe
[°]+****
È
Rotation angle
Setting range:
-45° to +45°
Set the rotation angle to -45° in earthed
systems using COSINE earth fault measurement
which is used for angle correction for ohmicinductive earth currents.
In electrical machines in bus-bar connection
with an isolated system, COSINE measurement
can be selected with a correction angle of
+45° because the earth current is often
composed of a capacitive component from the
system and an active component from an earth
fault load resistor.
DIR.
EARTHFAULT
δ1
[°]
****
È
DIR.
EARTHFAULT
δ2
[°]
****
È
DIR.
EARTHFAULT
δ3
[°]
****
Current transformer angle correction for Ie ≤ 100
mA
Setting range:
0° to 5°
Current transformer angle correction for 100
mA < Ie ≤ 200 mA
Setting range:
0° to 5°
Current transformer angle correction for Ie > 200
mA
Setting range:
0° to 5°
The high reactive current component in
compensated networks and the unavoidable air
gap of the window-type current transformers
often make compensation of the angle error of
the current transformer necessary. With the
programmed angle corrections the relay adapts
the measurement results to the characteristic of
the transformer. In isolated or earthed networks
this angle error compensation is not necessary.
G88700-C3527-07-7600
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MFR 7SJ551
6.8.11
Operating instructions
LOCKED ROTOR protection
È
PROTECTION
LOCKED ROTOR
LOCKED ROTOR
Æ
Beginning of the submenu LOCKED ROTOR
protection
ENABLED
DISABLED
Enabling the locked rotor protection
Disabling the locked rotor protection
È
LOCKED ROTOR
t-lr
[s]
5.00
Permissible locked rotor time
Setting range:
0 to 200 s
In most cases the permissible locked rotor time is
mentioned in the data of the manufacturer. As
the locked rotor condition is very critical, take a
safety margin of 1 s.
If the permissible start-up time is longer than
the permissible locked rotor time the locked
rotor protection function is inadequate: then the
zero speed function has to be used.
6.8.12
ZERO SPEED protection
If the permissible start-up time is longer than
the permissible locked rotor time the locked
rotor protection function is inadequate: then the
zero speed function has to be used.
È
PROTECTION
ZERO SPEED
ZERO SPEED
Æ
Beginning of the submenu ZERO SPEED
protection
ENABLED
DISABLED
Enabling the zero speed protection
Disabling the zero speed protection
È
Zero speed detection time
ZERO SPEED
t-zero [s]
10.0
Setting range:
0 s to 166 min
If, during zero speed alarm, the binary zero
speed input (connected to a binary tachometer)
stays energized during tzero , the relay will issue a
trip command.
¡Error! Argumento de modificador desconocido.
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MFR 7SJ551
6.8.13
Operating instructions
UNDERVOLTAGE protection (optional)
È
PROTECTION
UNDERVOLTAGE
UNDERVOLTAGE
Æ
Beginning of the submenu UNDERVOLTAGE
protection
ENABLED
DISABLED
Enabling the undervoltage protection
Disabling the undervoltage protection
È
UNDERVOLTAGE
Uo<
[Un]
.250
È
Undervoltage pick-up
Setting range:
0.05 to 1.2 ⋅ Un
Depending on the programmed voltage circuit
type U0<, Uln< or Uph< is displayed. As a default
U0< is displayed.
UNDERVOLTAGE
t Uo< [s]
.000
6.8.14
Undervoltage delay time
Setting range:
0 s to 166 min
OVERVOLTAGE protection (optional)
È
PROTECTION
OVERVOLTAGE
OVERVOLTAGE
Æ
Beginning of the submenu OVERVOLTAGE
protection
ENABLED
DISABLED
Enabling the overvoltage protection
Disabling the overvoltage protection
È
OVERVOLTAGE
Uo>
[Un]
.750
È
Pick-up value of the low set stage U>
Setting range:
0.05 to 1.2 ⋅ Un
Depending on the programmed voltage circuit
type U0>, Uln> or Uph> is displayed. As a default
U0> is displayed.
OVERVOLTAGE
t Uo> [s]
5.00
È
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
Trip time delay of the low set stage U>
Setting range:
0 s to 166 min
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
OVERVOLTAGE
Uo>>
[Un]
1.00
È
OVERVOLTAGE
t Uo>> [s]
1.00
È
Pick-up value of the high set stage U>>
Setting range:
0.05 to 1.2 ⋅ Un
Trip time delay of the high set stage U>>
Setting range:
0 s to 166 min
6.8.15 BREAKER FAILURE
PROTECTION
È
PROTECTION
BF TRIP
BF TRIP
Æ
Beginning of the submenu BREAKER FAILURE
PROTECTION
ENABLED
DISABLED
Enabling the breaker failure protection
Disabling the breaker failure protection
È
BF TRIP
EXTERN:DISABL
ED
EXTERN:
ENABLED
È
BF TRIP
I-bf
[In]
.500
È
BF TRIP
t-bf
[s]
10.0
È
Disabling the external control
Enabling the external control
Start of the breaker failure protection can be
initiated by an external protection relay. The trip
signal of the external protection device is
coupled into MFR 7SJ551 via a binary input.
Pick-up value of current stage
Setting range:
0 to 28 ⋅ In
Time stage
Setting range:
0 s to 166 min
When the trip command is generated timer tbf is
started. The timer continues to run for as long
as the trip command is maintained. If the circuit
breaker does not respond to the trip command
the timer runs to its set limit. If the then
measured current is higher than Ibf the breaker
failure protection energizes a second relay
output to trip the upstream circuit breaker to
clear the fault.
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
If the function is set to external control, start of
the breaker failure protection can be initiated by
an external protection relay. The trip signal of
the
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
external protection device is coupled into MFR
7SJ551 via a binary input. The timer tbf is
started. If the measured current is higher than Ibf
after tbf has elapsed, the breaker failure
protection energizes the breaker failure
protection relay output to trip the circuit breaker
to clear the fault. Deenergizing of the binary
breaker failure protection input only has effect
as soon as the measured current becomes
smaller than Ibf.
6.8.16
CURVE SWITCH
The submenu CURVE SWITCH only appears
when low set overcurrent protection or high set
overcurrent protection is enabled.
È
PROTECTION
CURVE SWITCH
CURVE SWITCH
Æ
Beginning of the submenu CURVE SWITCH
ENABLED
DISABLED
Enabling the curve switch function
Disabling the curve switch function
È
CURVE SWITCH
MODE:CONTINUO
US
MODE:
PULSE
Curve switch mode.
CONTINUOUS
MODE:
STATUS
È
PULSE
STATUS
MFR 7SJ551 switches
from curve 1 to curve 2
during the activation of the
curve switch binary input
MFR 7SJ551 switches
from curve 1 to curve 2
during the curve switch
time tCS, after the activation
of the curve switch binary
input
only for motors; depending
on motor status MFR
7SJ551 automatically
switches from curve 1 to
curve 2
If the curve switch mode CONTINUOUS is set,
no further menu item appears.
CURVE SWITCH
t-CS
[s]
10.0
G88700-C3527-07-7600
Curve switch activation time
Setting range:
0 s to 166 min
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
If the curve switch mode PULSE is set, this
menu item appears.
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
CURVE SWITCH
STATUS:
RUNNING
STATUS:STP/ST
RT
6.8.17
If the curve switch mode STATUS is set, this
menu item appears.
RUNNING
when the motor status is
RUNNING, curve 2 is
active, when the motor
status is STOPPED or
START curve 1 is active
STOPPED/START
when the motor status is
STOPPED or START, curve
2 is active, when the
motor status is RUNNING
curve 1 is active
BLOCK
With the BLOCK function MFR 7SJ551 provides
the possibility to block the overcurrent,
undercurrent and undervoltage characteristics
during motor or transformer inrush.
È
PROTECTION
BLOCK
Curve switch status
BLOCK
Æ
ENABLED
The submenu BLOCK only appears when
undercurrent protection, low set overcurrent
protection, high set overcurrent protection or
undervoltage protection is enabled.
Beginning of the submenu BLOCK
Enabling the block function
Disabling the block function
DISABLED
È
BLOCK
MODE:CONTINUO
US
MODE:
PULSE
BLOCK mode
CONTINUOUS
MODE:
STATUS
È
PULSE
STATUS
MFR 7SJ551 activates the
block function during the
activation of the block
binary input
MFR 7SJ551 activates the
block function during the
block time tBLOCK, after the
activation of the block
binary input
only for motors; depending
on motor status MFR
7SJ551 automatically
activates the block function
If the BLOCK mode CONTINUOUS is set, no
further menu item appears.
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
BLOCK activation time
BLOCK
t-BLOCK [s]
10.0
Setting range:
È
0 s to 166 min
Block status
BLOCK
STATUS:
RUNNING
STATUS:STP/ST
RT
È
If the block mode STATUS is set, this menu
item appears.
RUNNING
STOPPED/START
BLOCK
TIMERS:DISABL
ED
TIMERS:
ENABLED
when the motor status is
STOPPED or START, the
block function is active,
when the motor status is
RUNNING, the block
function is inactive
when the motor status is
RUNNING, the block
function is active, when the
motor status is STOPPED
or START, the block
function is inactive
Disabling the BLOCK TIMERS (‘block on pickup’). There will be no alarm and no trip
indication.
Enabling the BLOCK TIMERS (‘block on timers’).
There will be an alarm indication after pick-up,
but no trip.
È
BLOCK U.C.
Ph
I<:
ENABLED
Enabling BLOCK UNDERCURRENT
Disabling BLOCK UNDERCURRENT
I<:
DISABLED
È
Enabling BLOCK LOW SET OVERCURRENT
PHASE
Disabling BLOCK LOW SET OVERCURRENT
PHASE
BLOCK O.C.
Ph
I>:
ENABLED
I>:
DISABLED
È
Enabling BLOCK HIGH SET OVERCURRENT
PHASE
Disabling BLOCK HIGH SET OVERCURRENT
PHASE
BLOCK O.C.
Ph
I>>:
ENABLED
I>>:
DISABLED
È
BLOCK O.C.
Ie>:
ENABLED
e
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Ie>:
DISABLED
È
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Enabling BLOCK LOW SET OVERCURRENT
EARTH
BLOCK O.C.
Ie>>:
ENABLED
Disabling BLOCK LOW SET OVERCURRENT
EARTH
e
Ie>>:
DISABLED
È
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
Enabling BLOCK HIGH SET OVERCURRENT
EARTH
BLOCK U.V.
U<:
ENABLED
U<:
DISABLED
6.8.18
Disabling BLOCK HIGH SET OVERCURRENT
EARTH
Enabling BLOCK UNDERVOLTAGE
Disabling BLOCK UNDERVOLTAGE
EXTERNAL COMMAND
With the external command function an
immediate trip can be generated by activating a
binary input, for example to make an emergency
stop
.
È
PROTECTION
EXT. COMMAND
EXT. COMMAND
Æ
Beginning of the submenu EXTERNAL
COMMAND
ENABLED
DISABLED
Enabling the external command
Disabling the external command
È
EXT. COMMAND
t-EXT
[s]
5.00
Delay time
Setting range:
0 s to 166 min
After activating the external command binary
input, the delay timer tEXT is started. If the
binary input continues to be activated during
tEXT, the external command output will be
energized after tEXT has elapsed.
6.8.19
CIRCUIT BREAKER POSITION
With the circuit breaker position function the
position of the circuit breaker can be indicated.
È
PROTECTION
CB POSITION
CB POSITION
Æ
ENABLED
DISABLED
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Beginning of the submenu CB POSITION
Enabling the circuit breaker position
annunciation
Disabling the circuit breaker position
annunciation
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
After the circuit breaker position binary input is
activated the circuit breaker position LED
indicator will be energized.
G88700-C3527-07-7600
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MFR 7SJ551
6.9
Operating instructions
Settings for TRANSIENT DATA
In the TRANSIENT DATA the operator
determines how the fault recording is started.
È
SETTINGS
TRANSIENT
DATA
TRANSIENT
Æ DATA
INTERN
E⋅TERN
Beginning of the submenu TRANSIENT DATA
Enabling the internal triggering of the data
storage (triggering by fault)
Enabling the external triggering of the data
storage (triggering by binary input)
È
Data storage can be initiated by any protection
function (INTERN). The actual storage time
begins prematurely by a fixed pre-trigger time.
Total storage time is three seconds.
Data storage can also be initiated via a binary
input. The storage is triggered dynamically, in
these cases. Total storage time is three
seconds.
DATA STORAGE
BY:
Storage criterion
FAULT DETECTION
TRIP
FD
TRIP
The storage criterion can be the general fault
detection (FD) or the trip command (TRIP).
Especially for delay times larger than 3 seconds
storage by trip can be desirable, as for storage by
fault detection MFR 7SJ551 will not record
sampling values at the trip instant.
6.10
Settings for the REAL TIME CLOCK
MFR 7SJ551 is equipped with a real time clock.
In the REAL TIME CLOCK menu date and time
can be altered. Furthermore, time
synchronisation can be activated here.
È
SETTINGS
REAL TIME
CLOCK
RTC DATE &
Æ TIME
FORMAT:DD-MMYY
Beginning of the submenu REAL TIME CLOCK
Setting the date format to day - month - year
Setting the date format to month - day - year
FORMAT:MM-DDYY
È
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
REAL TIME
CLOCK
DATE:
0108-97
È
REAL TIME
CLOCK
TIME:
08:30:00
È
Date.
Depending on the date format the date is set
using the numerical keyboard. The dashes are
put in automatically. The day after 31-12-99
will be 01-01-00.
Time
The time is in European format (00:00:00 to
23:59:59). The colons are put in automatically.
RTC SYNC
DISABLED
ENABLED
Disabling the real time clock synchronization
Enabling the real time clock synchronization
MFR 7SJ551 provides the possibility to
synchronize the real time clock via a binary
input. For this purpose a mother clock or a
receiver for a DCF pulse must be connected.
Energizing the binary input will set the seconds
to zero. The minutes will be set to the nearest
value.
Example 1
A synchronizing pulse at 13:27:18 will set the
real time clock to 13:27:00.
Example 2
A synchronizing pulse at 13:27:48 will set the
real time clock to 13:28:00.
6.11
MARSHALLING of binary inputs, binary outputs and LED
indicators
6.11.1
General
As a factory setting the binary inputs, the
binary outputs and the LED indicators are not
marshalled. This means the relay will not be
able to perform any protection function. The
assignment of the different input and output
criteria must be marshalled according to on-site
conditions.
When the firmware programs are running, the
specific logic functions will be allocated to the
¡Error! Argumento de modificador desconocido.
physical input and output modules or LEDs in
accordance with the selection.
Example
An earth fault is registered from the low set
earth overcurrent time protection. This event is
generated in the device as a START (logical
function) and should be available at one or more
of the output contacts, for example output relay
3. The microcontroller must be advised that the
logical signal START E> should be transmitted
to the output relay 3.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Thus, when marshalling is performed two
statements of the operator are important:
1. Which logical annunciation generated in the
protection unit program should trigger an
output relay?
2. Which output relay should be triggered by
this logical annunciation?
The trip relays can be assigned to more than
one function. Up to 33 logical annunciations can
trigger one relay (maximum version), although
this is not a realistic situation.
One logical annunciation can be assigned to
more than one output relay, up to the maximum
number of output relays available.
È
SETTINGS
MARSHALLING
MARSHALLING
Æ BINARY INPUT
Æ
È
MARSHALLING
OUTPUT RELAYS
Æ
È
MARSHALLING
LED INDICATOR
Æ
A similar situation applies to binary inputs. In
this case external information (for example
blocking of the I>> stage) is connected to the
unit via an input module and should initiate a
logical function (namely blocking). The
corresponding question to the operator is then:
1. Which signal to a binary input should initiate
a reaction by the device?
2. Which reaction should be initiated?
The (optional) marshallable LED indicators can
be assigned to more than one function. Up to
30 logical annunciations are permitted.
Marshalling LED indicators is performed similar
to marshalling output relays. One logical
annunciation can be assigned to only one LED
indicator.
Beginning of the submenu MARSHALLING and
of the submenu BINARY INPUT
Beginning of the submenu OUTPUT RELAYS
Beginning of the submenu LED INDICATOR
When the MARHALLING menu is left, the
settings are permanently secured on EEPROM
and protected against power outage
6.11.2
Marshalling of the BINARY INPUTS
The unit contains 2 or 5 binary inputs
(dependent on model) which are designated
BINARY INPUT 1 to BINARY INPUT 5. They can
be marshalled in the submenu MARSHALLING
BINARY INPUT.
È
MARSHALLING
BINARY INPUT
BINARY INPUT
Æ 1
NORMALLY:
OPEN
È
BINARY INPUT
5
NORMALLY:
OPEN
NORMALLY:CLOS
ED
È
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
Beginning of the submenu MARSHALLING
BINARY INPUT
First a choice can be made for each individual
input as to whether the assigned function
should become operative in the NORMALLY
OPEN mode or in the NORMALLY CLOSED
mode:
NORMALLY OPEN
NORMALLY:CLOS
ED
È
NORMALLY CLOSED
The control voltage at
the input terminals
activates the function.
Control voltage
present at the
terminals turns off the
function, control
voltage absent
activates the function.
As a next step, each input function must be
assigned to one binary input. Scrolling down the
MARSHALLING BINARY INPUT menu the
different functions appear. The normally open or
normally closed status is displayed by ‘NO’ or
‘NC’ in the right upper corner of the display. By
pushing the arrow right key Æ the binary input
number can be set.
È
BINARY INPUT
NO
BLOCK:
1
E⋅ample
For assigning the BLOCK input signal to a binary
input the menu appears as showed on the left.
Binary inputs 2 and 4 are set normally closed.
BINARY INPUT
NC
BLOCK:
2
BINARY INPUT
NO
BLOCK:
3
BINARY INPUT
NC
BLOCK:
4
BINARY INPUT
NO
BLOCK:
5
È
The following input functions will appear if the
concerning protection functions have been
enabled. Otherwise these functions will not
appear. Refer to section 4 and 6.8 for a detailed
description of these input functions
¡Error! Argumento de modificador desconocido.
REMOTE RESET
For resetting the relay via a binary input instead
of the RI key at the front.
To obtain this possibility set the REMOTE
RESET function to EXTERN.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
REMOTE RESET
E⋅TERN:
ENABLED
E⋅TERN:DISABLE
D
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
Enabling the remote reset
Disabling the remote reset
This menu item will appear in the submenu
MARSHALLING BINARY INPUT. If disabled no
binary input assignment is requested.
τ-adjust
For adapting the warming-up time constants to
on-site conditions.
CURVE SWITCH
For switching from overcurrent curve set 1 to
overcurrent curve set 2.
BLOCK
For blocking the overcurrent, undercurrent or
undervoltage characteristics.
CW/CCW INPUT
For adapting the calculation of inverse current
and unbalance to the reverse rotation direction.
First a choice has to be made in the
MARSHALLING BINARY INPUT menu whether
the clockwise/counterclockwise determination is
performed internally or externally.
È
CW/CCW INPUT
MODE:
INTERN
MODE:
E⋅TERN
È
CW/CCW INPUT
DIRECTION:
CW
DIRECTION:
CW
Rotating direction determination MODE
INTERN
E⋅TERN
The direction of rotation is
determined in the ne⋅t menu line.
The direction of rotation is normally
clockwise. The binary input signal
will reverse the direction of rotation
to counterclockwise.
Rotating direction
CLOCKWISE
COUNTERCLOCKWISE
After setting the mode to INTERN the rotating
direction can be set. For reversing the direction
the relay has to be reprogrammed.
EMERGENCY RESTART
For resetting the thermal reserve buffers to
100%.
ZERO SPEED
For protecting the motor against stalled rotor by
connecting a binary tachometer to this ZERO
SPEED binary input.
BREAKER FAILURE TRIP
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For initiating start of the breaker failure trip by
an external protection relay. The trip signal of
the external protection device is coupled into
MFR 7SJ551 via the BREAKER FAILURE TRIP
binary input.
E⋅TERNAL COMMAND
For generating an immediate trip, for example to
make an emergency stop.
CIRCUIT BREAKER POSITION
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
For indicating the position of the circuit breaker.
When the binary circuit breaker position input is
energized one of the marshallable LED indicators
(assigned to circuit breaker position) will be
illuminated.
FAULT RECORDING
For initiating data storage.
SERIAL EVENT
For passing on a binary signal serially to the
station control system.
Example
The input function SERIAL EVENT is assigned to
normally open binary input 3. If binary input 3 is
energized the relay will send away a serial
message via its serial interface to the control
system that binary input 3 has been energized.
In the control system this message can be given
a special meaning, for e⋅ample “cubicle door
open”.
RTC SYNC
For synchronizing the real time clock.
6.11.3
Marshalling of the OUTPUT RELAYS
Dependent on the ordered model the unit
contains 4 output relays or 6 output relays (with
output 1 doubled). These outputs are make
contacts. One (breaker) output contact signals
the availability of the relay (MONITOR), its
allocation cannot be changed. The six make
contacts are designated OUTPUT 1 to OUTPUT
È
MARSHALLING
LATCH TIMER
OUTPUT RELAYS Æ
ENABLED
DISABLED
È
6 and can be marshalled in the menu
MARSHALLING OUTPUT RELAYS. Multiple
designations are possible, i.e. one logical
annunciation function can be routed to several
output relays and several logical annunciation
functions can be routed to one output relay.
Beginning of the submenu MARSHALLING
OUTPUT RELAYS and of the submenu LATCH
TIMERS
Enabling the latching timer
Disabling the latching timer
If enabled output signals will be locked for a
limited amount of time.
G88700-C3527-07-7600
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MFR 7SJ551
Operating instructions
LATCHED
RELAYS
t-reset [s]
600
È
Latching time
Setting range:
0 s to 166 min
The output relay will be locked until treset has
elapsed. This menu line will only appear if the
latching timer is enabled.
UNLATCHED
First a choice can be made for each individual
output relay as to whether it has to be locked
after excitation or not:
LATCHED
UNLATCHED
OUTPUT RELAY
1
È
LATCHED
È
OUTPUT RELAY
6
UNLATCHED
LATCHED
È
After disappearing of the
output condition the output
relay will drop off.
After disappearing of the
output condition and elapsing
of the latching time the output
relay will drop off.
Ne⋅t each output function must be assigned to
one or more output relays. Scrolling down the
MARSHALLING OUTPUT RELAYS menu the
different functions appear to the left and the
concerning output matrix lines to the right. The
latched or unlatched status is displayed by ‘-’
or ‘l’ in the upper line of the display. By
pushing the 0 to 6 numerical keys the desired
output relay numbers can be set. By pushing the
0 to 6 numerical keys a second time the setting
disappears.
Example
For assigning the TRIP L>> output signal to
output relays the menu appears as follows.
Outputs 2 and 4 are set latched.
RELAY
-ll-TRIP L>>: -----
To assign output 1 and output 4 to the high set
overcurrent trip signal push 1 and 4 once.
RELAY
-ll-TRIP L>>: 1-4--
If output 4 is set incorrectly and output 2 has to
be set, push 4 again and push 2 once.
RELAY
-ll-TRIP L>>: 12---
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
The following output functions will appear if the
concerning protection functions have been
enabled. Otherwise these functions will not
G88700-C3527-07-7600
Operating instructions
appear. Refer to section 4 and 6.8 for a detailed
description of these output functions.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
PRE-ALARM
For annunciating the pre-alarm condition. The
output will be energized after the thermal
reserve has decreased to the warning level.
TRIP θ-th
For thermal overload trip and annunciation. The
output will be energized after the thermal
reserve has decreased to zero.
START L1>
For annunciating pick-up of the low set
overcurrent protection function due to
overcurrent in phase 1.
START L2>
For annunciating pick-up of the low set
overcurrent protection function due to
overcurrent in phase 2.
START L3>
For annunciating pick-up of the low set
overcurrent protection function due to
overcurrent in phase 3.
START L>
For annunciating pick-up of the low set
overcurrent protection function due to
overcurrent in one or more of the phases.
TRIP L>
For low set phase overcurrent trip and
annunciation. The output will be energized after
the low set phase overcurrent delay time has
elapsed.
START e>
For annunciating pick-up of the low set
overcurrent protection function (or the
directional earth fault protection function) due
to earth overcurrent.
START φ>
Operating instructions
TRIP φ>
For directional earth fault trip and annunciation.
The output will be energized after the low set
earth overcurrent delay time has elapsed.
START L>>
For annunciating pick-up of the high set
overcurrent protection function due to shortcircuit in one or more of the phases.
TRIP L>>
For high set phase overcurrent trip and
annunciation. The output will be energized after
the high set phase overcurrent delay time has
elapsed.
START e>>
For annunciating pick-up of the high set stage
of the directional earth fault protection function
due to earth overcurrent in the protective
direction.
START φ>>
For annunciating pick-up of the directional earth
fault protection function due to earth
overcurrent in the protective direction.
TRIP e>>
For high set earth overcurrent trip and
annunciation. The output will be energized after
the high set earth overcurrent delay time has
elapsed.
TRIP φ>>
For directional earth fault trip and annunciation.
The output will be energized after the high set
earth overcurrent delay time has elapsed.
ALARM UB
For annunciating pick-up of the unbalance
protection function.
TRIP UB
For unbalance trip and annunciation. The output
will be energized after the calculated unbalance
delay time has elapsed.
For annunciating pick-up of the low set stage of
the directional earth fault protection function
due to earth overcurrent in the protective
direction.
ALARM U<
TRIP e>
For annunciating pick-up of the undervoltage
protection function.
For low set earth overcurrent trip and
annunciation. The output will be energized after
the low set earth overcurrent delay time has
elapsed.
¡Error! Argumento de modificador desconocido.
TRIP U<
For undervoltage trip and annunciation. The
output will be energized after the undervoltage
delay time has elapsed.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
ALARM U>
TRIP I<
For annunciating pick-up of the low set
overvoltage protection function.
For undercurrent trip and annunciation. The
output will be energized after the undercurrent
delay time has elapsed.
TRIP U>
For low set overvoltage trip and annunciation.
The output will be energized after the low set
undervoltage delay time has elapsed.
ALARM U>>
For annunciating pick-up of the high set
overvoltage protection function.
TRIP U>>
For low set overvoltage trip and annunciation.
The output will be energized after the low set
undervoltage delay time has elapsed.
START INHIBIT
For preventing the motor circuit breaker to close
before the motor regained sufficient thermal
reserve again.
LOCKED ROTOR
For locked rotor trip and annunciation. The
output will be energized after the calculated
locked rotor trip delay time has elapsed.
ALARM T
For annunciating temperature increase above
the overtemperature alarm level.
TRIP T
For overtemperature trip and annunciation. The
output will be energized as soon as the
measured temperature crosses the
overtemperature trip level.
ALARM I<
For annunciating pick-up of the undercurrent
protection function.
G88700-C3527-07-7600
Ie DIRECTION ->
For annunciating the forward direction as
determined by the directional earth fault
protection. Be aware that this output function is
not the trip condition of the directional earth
fault protection!
Ie DIRECTION <For annunciating the backward direction as
determined by the directional earth fault
protection. Be aware that this output function is
not the trip condition of the directional earth
fault protection!
ALARM ZERO SPEED
For annunciating pick-up of the zero speed
protection function. The output will be
energized after the binary tachometer has
energized the zero speed binary input.
TRIP ZERO SPEED
For zero speed trip and annunciation. The
output will be energized after the zero speed trip
delay time has elapsed.
BREAKER FAILURE TRIP
For breaker failure trip of the upstream circuit
breaker and for annunciation. The output will be
energized after the breaker failure trip time
stage has elapsed.
E⋅TERNAL COMMAND
For immediate or delayed trip after the binary
e⋅ternal command input is energized. The output
will be energized after the external command
trip delay has elapsed.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
6.11.4
Operating instructions
Marshalling of the LED INDICATORS (optional)
Dependent on the ordered model the unit
contains 4 marshallable LED indicators. The
allocation of the five standard LED indicators
cannot be changed. The 4 marshallable LED
È
MARSHALLING
LED 1
LED INDICATOR Æ
NONMEMORIZED
MEMORIZED
È
indicators are designated LED 1 to LED 4 and
can be marshalled in the menu MARSHALLING
LED INDICATOR.
Beginning of the submenu MARSHALLING LED
INDICATOR
First a choice can be made for each individual
LED indicator as to whether it has to be
memorized after excitation or not:
NON-MEMORIZED After disappearing of the
È
LED 4
NONMEMORIZED
MEMORIZED
excitation condition the LED
indicator will drop off.
After disappearing of the
excitation condition the LED
indicator will stay
illuminated until it is reset.
MEMORIZED
È
As a next step, each excitation condition must
be assigned to one LED indicator. Scrolling
down the MARSHALLING LED INDICATOR
menu the different functions appear. The
memorized or non-memorized status is displayed
by ‘NM’ or ‘ME’ in the upper line of the display.
Initially the excitation functions are not
marshalled, designated by ‘⋅’. By pushing the
arrow right key Æ the binary input number can
be set.
Example
For assigning the TRIP L>> excitation signal to a
LED indicator the menu appears as follows. LED
indicators 2 and 4 are set latched.
È
È
LED INDICATOR
TRIP L>>:
⋅
LED INDICATOR
NM
TRIP L>>:
1
LED INDICATOR
ME
TRIP L>>:
2
LED INDICATOR
NM
TRIP L>>:
3
LED INDICATOR
ME
TRIP L>>:
4
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
G88700-C3527-07-7600
Operating instructions
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
The following excitation functions will appear if
the concerning protection functions have been
enabled. Otherwise these functions will not
appear. The excitation of the LED indicators is
similar to a large extent to the energizing of the
output relays. Refer to the output functions
described briefly in the preceding section
6.11.3. Refer to section 4 and 6.8 for a detailed
description of these output functions.
TRIP θ-th
START L>
TRIP L>
START e>
START φ>
TRIP e>
TRIP φ>
START L>>
TRIP L>>
START e>>
START φ>>
TRIP e>>
TRIP φ>>
ALARM UB
TRIP UB
ALARM U<
TRIP U<
ALARM U>
TRIP U>
ALARM U>>
TRIP U>>
START INHIBIT
LOCKED ROTOR
ALARM T
TRIP T
ALARM I<
TRIP I<
Ie DIRECTION ->
Ie DIRECTION <ALARM ZERO SPEED
TRIP ZERO SPEED
BREAKER FAILURE TRIP
EXTERNAL COMMAND
One excitation function is available for LED
indication only:
CIRCUIT BREAKER POSITION
For indicating the position of the circuit breaker.
The LED indicator will be illuminated when the
binary circuit breaker position input is energized.
There is no use in setting a memorized LED
indicator for CIRCUIT BREAKER POSITION.
6.12
Settings for SERIAL COMMUNICATION (optional)
In the SERIAL COMMUNICATION menu the
serial communication facility can be matched to
È
SETTINGS
SERIAL.COMM.
SERIAL COMM.
Æ ADDRESS:
0
the connected personal computer or station
management system.
Address number
Setting range:
0 to 254
È
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Operating instructions
With the relay address different relays
incorporated in a control system can be
distinguished from each other.
SERIAL COMM.
SUBADDR.:
0
Subaddress number
Setting range:
0 to 254
È
The subadress is needed when the relay is
incorporated in an elder Siemens SINAUT LSA
station control system.
SERIAL COMM.
BAUDRATE:
9600
BAUDRATE:
19200
Baudrate
2400, 4800, 9600, 19200 or 38400
BAUDRATE:
38400
BAUDRATE:
2400
BAUDRATE:
4800
È
SERIAL
INTERFACE
TYPE:
RS485
TYPE:
OPTICAL
È
Type of serial interface
RS-485 or optical
Both interfaces can be used for communicating
with a personal computer or a control system. It
is not possible to communicate with both
interfaces at a time. The type of the serial
interface set in this menu line should correspond
to the communication link desired at that
moment.
Often the optical interface is connected to an
input/output unit of the control system and the
RS-485 interface to a notebook. The normal
type setting is OPTICAL then; only for setting
and commissioning using a notebook the type
setting is changed to RS-485.
Most personal computers only provide a RS-232
interface for communication with the relay. To
achieve communication the selected interface
should be connected via a converter to RS-232.
SERIAL COMM.
EVENT:
DISABLED
Enabling the SERIAL EVENT
Disabling the SERIAL EVENT
EVENT:
ENABLED
For passing on a binary ‘serial event’ input
signal to the station control system. In the
control system this message can be given a
È
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MFR 7SJ551
Operating instructions
special meaning, for e⋅ample “cubicle door
open”.
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Operating instructions
SERIAL COMM.
PRTCL: VDEWerw
PRTCL:
LSA
PRTCL:
VDEW
È
LSA
VDEW
VDEW-erw
ILSA-protocol according to DIN
19244
international protocol according to
IEC 870-5
international protocol according to
IEC 870-5, e⋅tended with e⋅tra
annunciations specific for
MFR7SJ551
SERIAL COMM.
BLOCK:
DISABLED
Disabling the serial communication BLOCK
Enabling the serial communication BLOCK
BLOCK:
ENABLED
For commissioning it can be useful to prevent the
relay from serial sending of analogue signal
values. This is achieved by enabling the serial
communication block. Thus, these messages
cannot be confused with messages which occur
during real operation.
È
6.13
Communication protocol
Putting the relay into operative mode (ON LINE)
When the relay is fully parametrized it must be
set into ON LINE mode to enable it to perform its
protection tasks. All settings should be carefully
checked.
After starting in the OFF LINE mode and selecting
the OPERATING MODE the display will present
the initial display.
OPERATING
MODE
OFF LINE
Depressing the Æ key will activate the operating
mode menu part and the display will show:
ON LINE OK ?
ARE YOU SURE
?
and after appro⋅imately two seconds:
The symbol in the right corner of the lower te⋅t
row is flashing. Depressing the backspace key
will change the mode from OFF LINE to ON LINE
and the display will present:
OPERATING
MODE
ON LINE
The red MONITOR LED indicator will drop off and
the green ON LINE LED indicator will illuminate. It
is not possible to change any setting in the ON
LINE mode.
Depressing any other key instead of the
backspace key will cancel the setting to ON LINE
and the initial display will appear again.
To set the relay back to OFF LINE mode this
identical procedure has to be followed again.
ON LINE OK ?
TYPE
BACKSPACE
„
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Operating instructions
6.14
Annunciations
6.14.1
Introduction
After a network fault, annunciations and
messages provide a survey of important fault
data and the function of the relay, and serve for
checking sequences of functional steps during
testing and commissioning. Further, they
provide information about the relay itself during
normal operation.
The annunciations generated in the relay are
present in various ways:
− LED indications in the front plate of the relay
(figure 6.1).
È
MEASURED
VALUES
ON LINE
È
COUNTERS
ON LINE
È
ALARM/TRIP
DATA
ON LINE
È
DEMAND
AMMETER
ON LINE
È
RUNNING HOURS
ON LINE
È
MANUFACT.
DATA
ON LINE
− Binary outputs via the connections of the
relay.
− Indications in the display on the front plate or
on the screen of a personal computer, via the
serial interface (optional).
− Transmission via the serial interface to local
or remote control facilities
Most of these annunciations can be relatively
freely allocated to the LED indicators and binary
outputs (see section 6.11).
To call up annunciations on the operator panel
scroll to the concerning submenus.
MEASURED VALUES
Æ
Æ
Æ
Æ
Æ
Indication of operational measured values
(currents, voltage, thermal reserve, etc.).
COUNTERS
Annunciation for circuit breaker operation
statistics, that is counters for tripping
commands and accumulated short-circuit
currents.
ALARM/TRIP DATA
Event annunciations for the last three network
faults.
DEMAND AMPERE METER
Dynamic and maximum 8 minutes and 15
minutes averages of the measured currents.
Æ
È
RUNNING HOURS
Actual running hours (since previous start-up)
and total running hours.
MANUFACTURING DATA
Ordering code, serial number and software
version.
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6.14.2
Operating instructions
MEASURED VALUES
The steady state RMS operating values can be
read out any time in the submenu MEASURED
VALUES.
in section 6.7. In the following menu description
only values zero are shown. In practice the
actual values appear.
The data are displayed in absolute primary
values. To ensure correct primary values, the
rated data must have been entered to the
device in the submenu CHANNELS as described
Some of the described menu items only appear
when corresponding functions are enabled or
available (if ordered as option).
È
MEASURED
VALUES
ON LINE
RMS VALUES
Æ ON LINE
RMS VALUES
[A]
Æ L1
.000
È
RMS VALUES
L2
[A]
.000
Operational current values
Depending on the magnitude the current unit is A
or kA.
È
RMS VALUES
L3
[A]
.000
È
RMS VALUES
e
[A]
.000
È
È
RMS VALUES
Uo
[V]
.000
È
È
RMS VALUES
Iφ
[A]
.000
È
THERMAL
RESERVE
ON LINE
THERMAL
Æ RESERVE
θ-rotor [%]
100
È
THERMAL
RESERVE
θ-stator[%]
100
Operational voltage value
Depending on selected circuit type, residual
voltage, line-to-line voltage or phase to earth
voltage is displayed. Depending on the magnitude
the voltage unit is V or kV.
Earth fault component for directional earth fault
protection.
Depending on the selected measuring principle
(COSINE or SINE) here the value Ie ⋅ cos φ or Ie ⋅
sin φ is displayed.
Thermal reserve
For motors the rotor thermal reserve and the
stator thermal reserve are displayed. For nonrotating objects there is only one thermal
reserve buffer, denominated with “θ-th”.
È
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Operating instructions
THERMAL
RESERVE
TrueRMS [A]
.012
È
UNBALANCE
ON LINE
UNBALANCE
[A]
Æ I2
.000
È
TEMPERATURES
ON LINE
TEMPERATURES
Æ TEMP 1 [°C]
40.0
È
TEMPERATURES
TEMP 2 [°C]
40.0
È
True RMS current
The displayed true root mean square current is
the highest momentary phase current used by
the thermal overload function. As this
contains all harmonic components a small
noise current will be displayed even when
there is no actual operation current.
Inverse current
The inverse current is calculated out of the
three phase currents according to the symmetric
components method.
Temperatures
The temperatures are measured by the 2 or 8
RTD elements and processed in the interface unit
(optional). When these menu lines are recalled,
the interface unit will send the temperature
values to the relay unit. This will take a short
moment, in which 4 stars “****” are shown
instead of a temperature value.
È
TEMPERATURES
TEMP 8 [°C]
40.0
È
TEMPERATURES
AMBIENT[°C]
40.0
È
MOTOR STATUS
ON LINE
Æ
MOTOR STATUS
STOPPED
Motor status
STOPPED, START or RUNNING
Refer to section 4.8 for a detailed description.
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6.14.3
Operating instructions
COUNTERS
The submenu COUNTERS provides circuit
breaker operation statistics. Counter status and
stores are secured against auxiliary voltage
failure.
È
COUNTERS
ON LINE
COUNTERS
Æ RESET
DATE:
0108-97
Beginning of the submenu COUNTERS. After
that, the last time the counters were reset is
displayed.
È
ALARM
COUNTERS
ALARM COUNTER
Æ GENERAL: n=
0
È
ALARM COUNTER
PHASE: n=
0
The alarm counters show the total number of
alarms since the last reset date, and further the
number of alarms due to phase current faults,
earth current faults and voltage faults.
È
ALARM COUNTER
EARTH: n=
0
È
ALARM COUNTER
VOLTAGE: n=
0
È
TRIP COUNTERS
Æ
TRIP COUNTER
n=
0
È
TRIP COUNTER
ΣI-TRIP [A]
.000
The number of trip commands initiated by
7SJ551 is counted. Additionally the interrupted
currents are accumulated and stored.
È
COUNTERS
RESET
RESET
Æ COUNTERS ?
ARE YOU SURE
?
RESET
COUNTERS ?
TYPE
BACKSPACE „
To reset the counters the backspace key has to
be used. Resetting counters is possible in ON
LINE mode.
The symbol in the right corner of the lower text
row is flashing. Depressing the backspace key
will set all counters back to zero. A new
COUNTERS RESET DATE is stored.
Depressing any other key instead of the
backspace key will cancel the reset and the
COUNTERS RESET display will appear again.
6.14.4
ALARM / TRIP DATA
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Operating instructions
The annunciations which occurred during the
last three networks faults can be read off in the
front panel or via the serial interface. When a
further fault occurs, the data relating to the
eldest are erased. These annunciations can be
read off in the submenu ALARM/TRIP DATA.
Only fault annunciations related to available and
enabled functions will appear in this menu.
There are two separate fault data buffers, one
for the last three alarms and one for the last
three trips. The different alarms and trip buffers
are numbered separately.
ALARM/TRIP
DATA
ON LINE
ALARM DATA
Æ ON LINE
ALARM EVENT
Æ NR.
n
:
23
n-1 :
22
n-2 :
21
Example
Alarm number 23 has nothing to do with trip
number 23 (or only by coincidence). In most
cases more alarms than trips occur, so alarm
protocol number 23 will probably concern the
same fault as trip protocol number 15.
To match the alarm protocol and the trip
protocol concerning the same network fault the
RTC ALARM TIME and the RTC TRIP TIME
should be compared.
The submenu ALARM DATA gives an overview
of the status of all enabled protection functions.
Beginning of the menu ALARM/TRIP DATA and
of the submenu ALARM DATA. Display of the
most recent alarm number, designated with ‘n’.
Depress the Æ key to recall the two preceding
alarm protocols, designated with ‘n-1’ and ‘n2’.
È
RTC ALARM
DATE
n
0108-97
È
RTC ALARM
TIME
n
15:05:15
È
ALARM CIRCUIT
n
-- -- -- È
Alarm date and time
Refers to the moment of pick-up of one of the
protection functions.
Alarm circuit
L1, L2, L3, e and/or U
In this menu part the measuring circuits are
indicated via which a fault has been detected.
THERM.OVERLOA
D
n
--- [s]
.000
È
OVERTEMPERATU
RE
n
--- [s]
.000
È
UNDERCURRENT
n
--- [s]
.000
È
LOW SET O.C.
Ph
n
--- [s]
.000
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È
HIGH SET O.C.
Ph
n
--- [s]
.000
È
LOW SET O.C.
e
n
--- [s]
.000
È
HIGH SET O.C.
e
n
--- [s]
.000
È
UNBALANCE
n
--- [s]
.000
È
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Operating instructions
Function status and alarm or trip duration time.
In these menu lines all enabled functions and
their states at the moment of pick-up are
displayed. The following three states are
possible:
---
No alarm. The concerning function did
not detect a fault.
ALM
Alarm. The concerning function had
detected a fault but did not trip. The
displayed time is the time between pickup of the function and drop off of the
alarm condition.
TRP
Trip. The concerning function had
detected a fault and tripped. The
displayed time is the time between
generation of the trip signal and drop off
of the trip signal.
Be aware that the displayed time is not the
reaction time of the relay, but the total time a
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Operating instructions
LOCKED ROTOR
n
--- [s]
.000
È
ZERO SPEED
n
--- [s]
.000
È
UNDERVOLTAGE
n
--- [s]
.000
È
OVERVOLTAGE >
n
--- [s]
.000
function is in ALARM state or the total time a
function is in TRIP state. This means the
displayed time contains the circuit breaker
reaction time.
For the thermal overload protection the tripping
time recording differs. Counting of the TRIP
time starts when the thermal reserve has
decreased to the warning level θwarn. Counting
stops when the thermal overload function has
taken up the TRIP state and the thermal reserve
has increased to the warning level θwarn again.
È
OVERVOLTAGE
>>
n
--- [s]
.000
È
E⋅T. COMMAND
n
--- [s]
.000
È
TRIP DATA
ON LINE
TRIP EVENT
Æ NR.
n
:
15
n-1 :
14
Beginning of the submenu TRIP DATA and
display of the most recent trip number,
designated with ‘n’. Depress the Æ key to recall
the two preceding trip protocols, designated
with ‘n-1’ and ‘n-2’.
n-2 :
13
È
RTC TRIP DATE
n
0108-97
È
RTC TRIP TIME
n
15:05:15
È
I-TRIP Ph
n
[A]
.000
È
I-TRIP e
n
[A]
.000
È
I-TRIP φ
n
[A]
.000
Trip date and time
Refers to the moment of trip of one of the
protection functions.
Operational values at the moment of trip
For each recorded operational quantity the value
is displayed at the moment of trip by one of the
protection functions.
Refer to section 6.14.2 for a description of the
operational measurements.
È
Uin-TRIP
n
[V]
.000
È
I-TRIP-0seq
n
[A]
.000
È
I-TRIP-norm
n
[A]
¡Error! Argumento de modificador desconocido.
.000
È
I-TRIP-inv
n
[A]
.000
È
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MFR 7SJ551
Operating instructions
Calculated values of the current components
according to the symmetrical components
method. For 2-phase connection the menu item
θ-TRIP-rotor
n
[%]
.000
È
θ-TRIP-stator
n
[%]
.000
‘I-TRIP-0seq” disappears and an e⋅tra menu
item appears, namely “UB I2-TRIP”.
For motors the rotor thermal reserve and the
stator thermal reserve are displayed. For nonrotating objects only one value is displayed,
denominated by “θ-TRIP”.
È
TEMPERATURE 1
n
[°C]
.000
Temperature values at the moment of trip
È
TEMPERATURE 2
n
[°C]
.000
È
È
TEMPERATURE 8
n
[°C]
.000
6.14.5
DEMAND AMPERE METER
The submenu DEMAND AMPEREMETER
provides display of
− the dynamic 8 minutes average of the
measured currents
− the maximum 8 minutes average of the
measured currents since the last reset
È
DEMAND
AMMETER
ON LINE
AMMETER RESET
01Æ DATE:
08-97
È
DEMAND
AMMETER
8m
[A]
.000
È
− the dynamic 15 minutes average of the
measured currents
- the maximum 15 minutes average of the
measured currents since the last reset.
Beginning of the submenu DEMAND
AMPEREMETER. After that, the last time the
meter was reset is displayed.
Eight minutes average of the measured currents
This is the calculated average of the three root
mean square phase currents over the last eight
minutes.
8m-MA⋅ [A]
.000
DEMAND
AMMETER
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È
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Operating instructions
Eight minutes maximum of the measured
currents.
DEMAND
AMMETER
15m
[A]
.000
È
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This is the highest eight minutes average since
the last reset. This allows the user to check
correct dimensioning of network components.
Fifteen minutes average of the measured currents
This is the calculated average of the three root
mean square phase currents over the last fifteen
minutes.
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Operating instructions
Fifteen minutes maximum of the measured
currents
DEMAND
AMMETER
15m-MA⋅ [A]
.000
This is the highest fifteen minutes average since
the last reset. This allows the user to check
correct dimensioning of network components.
È
DEMAND
AMMETER RESET
RESET
Æ COUNTERS ?
ARE YOU SURE
?
RESET
COUNTERS ?
TYPE
BACKSPACE „
To reset the demand amperemeter the backspace
key has to be used. Resetting the demand
amperemeter is possible in ON LINE mode.
The symbol in the right corner of the lower text
row is flashing. Depressing the backspace key
will set the values back to zero. A new DEMAND
AMMETER RESET DATE is stored.
Depressing any other key instead of the
backspace key will cancel the reset and the
DEMAND AMMETER RESET display will appear
again.
6.14.6
RUNNING HOURS
The submenu RUNNING HOURS provides
display of the actual running hours (since
previous start-up) of the motor and of the total
running hours since last reset. This menu will
only appear when the DEVICE TYPE is set to
ROTATING.
È
RUNNING HOURS
RUN HRS RESET
ON LINE
01Æ DATE:
08-97
È
RUNNING HOURS
ACTUAL [h]
.000
È
RUNNING HOURS
TOTAL
[h]
.000
È
G88700-C3527-07-7600
Beginning of the submenu RUNNING HOURS.
After that, the last time the meter was reset is
displayed.
Actual running hours since previous start-up
The time unit is minutes or hours. The value will
be reset to zero automatically when MFR 7SJ551
detects a new start.
Total running hours since last reset.
The time unit is minutes or hours. The value can
only be set to zero by resetting it in the next
menu line.
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Operating instructions
RUNNING HOURS
RESET
RESET RUN
Æ HRS?
ARE YOU SURE
?
RESET RUN
HRS? TYPE
BACKSPACE
„
To reset the running hours counter the backspace
key has to be used. Resetting the running hours
counter is possible in ON LINE mode.
The symbol in the right corner of the lower text
row is flashing. Depressing the backspace key
will set the values back to zero. A new RUNNING
HOURS RESET DATE is stored.
Depressing any other key instead of the
backspace key will cancel the reset and the
RUNNING HOURS RESET display will appear
again.
6.14.7
MANUFACTURER DATA
In the submenu MANUFACTURER DATA,
ordering code, serial number and software
version can be read out.
È
MANUFACT.
DATA
ON LINE
ORDERING
Æ CODE:
7SJ55142BA00-3A
È
In OFF LINE mode the submenu DEFAULT
VALUES will be part of the MANUFACTURER
DATA menu. Refer to section 6.15 for a detailed
description of how to reset all settings to default
values.
Beginning of the submenu MANUFACTURER
DATA
Ordering code
As an example here the maximum version with
sensitive earth current measurement is shown.
The last character of the ordering code can be A,
B, C or D, depending on the ordered interface
unit. If the interface is ordered later or if this relay
is part of a batch delivery, this character will be
A. In this case, after mounting the interface unit
the displayed last character of the ordering code
will stay “A”. This has no influence on the good
operation of the relay.
SERIAL
NUMBER:
NL9708001029
È
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Serial number
Here the serial number of the relay unit is
displayed. If the relay unit is inserted in an other
housing the serial number of the relay unit and
the housing will differ. Refer to this menu readout serial number in your correspondence. (This
serial number is also registered on a sticker on
the draw-out module.)
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MFR 7SJ551
Operating instructions
SW VERSION
MFR
A.9 06-12-96
È
OPTION
FIRMWARE
B.6 08-08-96
B
È
MALFUNCTION
NO ERRORS
Firmware version relay unit
Behind the firmware version the date of release
of this firmware is shown.
Firmware version interface unit
This menu line will only appear when there is an
interface unit connected. Behind the firmware
version the date of release of this firmware is
shown, together with the ordering type (the last
character of the ordering code: B, C or D).
Self-monitoring annunciation
Normally here “NO ERRORS” can be read. The
following messages are shown when the relay
has an internal failure. (Refer to section 7.3 for a
detailed description.)
HW: AUX. SUPPLY
HW: E2PROM
HW: RAM
HW: REF.VOLTAGE
HW: ROM
HW: TRIP COIL
SW: MLFB
SW: SW ERROR
6.15
Resetting all settings to factory settings
MFR provides the possibility to reset all
parameters back to factory settings. Therefore
the submenu DEFAULT VALUES has to be
recalled. This submenu will only be available in
È
MANUFACT.
DATA
OFF LINE
OFF LINE mode. Initialization of the parameter
memory has to be executed always after
firmware exchange (EPROM set).
ORDERING
Æ CODE:
7SJ55142BA00-3A
È
È
È
È
È
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Operating instructions
DEFAULT
VALUES
INIT MEMORY
INIT MEMORY
Æ OK ?
ARE YOU SURE
?
INIT MEMORY
OK ?
TYPE
BACKSPACE „
To initialize the memory the backspace key has
to be used.
Depressing the backspace key will lead to a new
dialogue line, in which the initialization action has
to be reconfirmed.
È
DEFAULT
VALUES
RECONFIRM
INIT MEMORY
Æ OK ?
ARE YOU SURE
?
INIT MEMORY
OK ?
TYPE
BACKSPACE „
* INIT
MEMORY *
„„„„„„„„„„„„„„„
***** DONE
*****
PRESS ANY
KEY
The symbol in the right corner of the lower text
row is flashing. Depressing the backspace key
will set all parameters back to initial settings.
Depressing any other key instead of the
backspace key will cancel the initialization and
the INIT MEMORY display will appear again.
While initializing, the display will look as
showed on the left; the lowest line shows a
‘running’ row of symbols.
After approximately 15 seconds the display will
show that it is finished. After pressing a key the
relay will start up again.
After initialization the relay must be
parametrized according to on-site conditions.
The default values are used in the settings
description of the preceding sections.
¡Error! Argumento de modificador desconocido.
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6.16
Testing and commissioning
6.16.1
General
Prerequisite for commissioning is the completion
of the preparation procedures detailed in sections
5 and 6.
!
Warning
Hazardous voltages are present in the
electrical equipment during operation.
Non-observance of the safety rules can
result in personal injury or property
damage.
Only qualified personnel shall work on
and around this equipment after
becoming thoroughly familiar with all
warnings and safety notices of this
manual as well as with the applicable
safety regulations.
Particular attention must be drawn to
the following:
− The earthing screw of the device
must be connected solidly to the
protective earth conductor before
any other connection is made.
− Hazardous voltages can be present
on all circuits and components
connected to the supply voltage or
to the measuring and test
quantities.
− Hazardous voltages can be present
in the device even after
disconnection of the supply voltage
(storage capacitors!).
− The limit values given in the
Technical data (section 3) must not
be exceeded at all, not even during
testing and commissioning.
When testing the unit with a secondary injection
test set, it must be ensured that no other
measured values are connected and that the
tripping leads to the circuit breaker trip-coils have
been interrupted.
G88700-C3527-07-7600
Operating instructions
DANGER!
Secondary connections of the current
transformers must be short-circuited
before the current leads to the relay are
interrupted!
If a test switch is installed which
automatically short-circuits the current
transformer secondary leads, it is
sufficient to set this switch to the "Test"
position. The short-circuit switch must be
checked beforehand.
It is recommended that the actual setting for the
relay be used for the testing procedure. If these
values are not (yet) available, test the relay with
the factory settings or reasonable alternatives.
In the following description of the test sequence
values will be used that will be stated with each
test.
For almost all functional tests a single-phase
current source is sufficient. However, if
asymmetrical currents occur during the test and
the unbalance protection has been selected, it is
likely that the unbalance protection will
frequently operate. This is of no concern because
the condition of steady-state measured values is
monitored and, under normal operating
conditions, these are symmetrical; under short
circuit conditions the unbalance protection will
normally not activate a trip command (depending
on the concerning delay timers).
For testing the rotor thermal overload function
and the unbalance function a three phase current
source is necessary.
NOTE! The accuracy which can be achieved
during testing depends on the accuracy of the
testing equipment. The accuracy values
specified in the Technical data can only be
reproduced under the reference conditions set
down in IEC 255 or VDE 0435/ part 303 resp.
and with the use of precision measuring
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
instruments. The tests are therefore to be
looked upon purely as functional tests.
During all the tests it is important to ensure that
the output relay contact(s) close (during a trip
command activation), that the proper indications
appear at the LED's and the output relays for
remote signalling. If the 7SJ551 relay is
connected to a central memory device via the
serial interface, correct communication between
the relay and the master station must be
checked.
Stored indications are not erased automatically
with a new pick-up of the relay or replaced by
new annunciations. For a clear overview the LED
indicators should therefore be reset after each
test. Reset at least once by both of the possible
methods: the reset key RI on the front plate or
via the remote reset binary input (if this function
has been selected).
6.16.2
For a NON-ROTATING device the described
methods of testing are equally valid, in some
cases however they will be simpler.
!
Caution
For the normal current circuits, test
currents larger than 6 times In, and for the
Ie sensitive current circuit, test currents
larger than 4 times In may overload and
damage the relay current input channels
if applied continuously. Observe a cooling
period if necessary.
Testing the measurement of operational values
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
L3
In
CT RATIOPh
e
Ien
CT RATIOe
Uin
U select
Un
VT-RATIO
All described tests are done with a setting for a
ROTATING device, because than all the
protection functions are available.
Setting
ENABLED
ENABLED
ENABLED
1
150
ENABLED
1
150
ENABLED
Uln or UPh or U0
110
60
¡Error! Argumento de modificador desconocido.
Move to the menu part MEASURED VALUES (ON
LINE) and select the menu part RMS-values on
the display.
On injecting the nominal value In = 1 A alternately in the different 1 A phase and earth leads, the
correct RMS value of 150 A must be calculated
and shown on the display.
On administering the nominal secondary value of
110 V to the 110 V lead, the correct RMS value
of 6.6 kV must be calculated and shown on the
display.
G88700-C3527-07-7600
MFR 7SJ551
6.16.3
Operating instructions
Testing the motor status
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Ino load
CHANNELS
L1
L2
L3
In
6.16.4
Setting
1.00 ⋅ In
ROTATING
.100 A
ENABLED
ENABLED
ENABLED
1
Move to the menu part MEASURED VALUES (ON
LINE) and select the menu part MOTOR STATUS
on the display. With no current injected the
display shows: ‘STOPPED’.
MFR 7SJ551 derives the motor status out of the
level Itop = 1.125 ⋅ In and the level Ino load.
On injecting the value I = 1.12 A in one of the 1
A leads, the display should still show:
‘STOPPED’. Raise the injected current over 1.125
A. The display should show: ‘START’. Decrease
the current to Iflc (1.00 A). The relay should
show: ‘RUNNING’. Decrease the current under
Ino load. The display should show ‘STOPPED’.
Testing the rotor thermal overload protection
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Istart
tstart
kinv
nwarm
ncold
CHANNELS
L1
L2
L3
In
PROTECTIONS
THERMAL OVERLOAD
τ1,stat
pweight
cstop,rot
START INHIBIT
EMERGENCY RESTART
Setting
1.00 ⋅ In
ROTATING
4.00 ⋅ In
10.0 s
5.00
2
3
ENABLED
ENABLED
ENABLED
1
For testing the rotor thermal overload function a
three-phase test case is required. Disable all other
protection functions. Set the stator thermal
overload to a very large time constant to be sure
it will not trip earlier than the rotor thermal
overload protection.
Marshall the thermal overload protection to one
of the output relays.
For test-purposes it is recommended to marshall
the emergency restart function to one of the
inputs, in order to be able to reset the rotor
thermal reserve manually back to 100%.
ENABLED
999 min
1.00
2.00
ENABLED
ENABLED
Checking the steady state rotor thermal reserve
Move to the menu part MEASURED VALUES (ON LINE) and select the menu part THERMAL RESERVE
ROTOR on the display. Initially the displayed value will be 100% (Ipreload,rotor = 0).
Inject a symmetric three-phase current I = 1.20 A. The rotor thermal reserve will decrease. The steady
state value can be calculated out of the formulas for the rotor thermal overload protection:
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
k 2rotor =
τ rotor =
Operating instructions
ncold
3
=
=3
ncold − nwarm
3−2
−ncold ⋅ t start
⎛
k 2 ⋅ I2flc ⎞
⎟⎟
ln⎜⎜1 − rotor
I2start ⎠
⎝
=
−3 ⋅ 10.0
= 1445
. s
⎛
3 ⋅ (100
. )2 ⎞
⎟
ln⎜1 −
(400
. )2 ⎠
⎝
First the equivalent heating current is calculated. For a symmetric current only a normal component will
result:
I2heating = I2norm + k inv ⋅ I2inv = I2norm + 5 ⋅ I2inv = I2 = (120
. )2 = 144
.
Substituting this value in the basic iterative equation gives:
t
t ⎞
t ⎞
⎛
−
−
⎛
−
2
2
2
2
2
τ rotor
τ rotor ⎟
⎜
= 144
Ith, rotor (t) = Ipreload, rotor − Iheating ⋅ e
+ Iheating = Iheating ⋅ 1 − e
. ⋅ ⎜1 − e 144.5 ⎟ For t = ∞ the
⎟
⎜
⎟
⎜
⎠
⎝
⎠
⎝
(
)
steady state value of the thermal rotor current will be the injected current:
I2th, rotor (t = ∞) = 144
.
The formula for the rotor thermal reserve is:
θ th, rotor (t) =
k 2rotor ⋅ I2flc − I2th, rotor (t)
k 2rotor ⋅ I2flc
⋅ 100% =
3.00 − I2th, rotor (t)
3.00
⋅ 100%
The steady state thermal reserve will be:
θ th, rotor (t = ∞) =
3.00 − 144
.
⋅ 100% = 52.0%
3.00
Check if the displayed value for the rotor thermal reserve decreases to 52.0%.
Checking the trip time (cold condition)
Check the trip time with cold condition (θth,rotor = 100%). Inject a symmetric three-phase overload current I
= 3.00 A (step function). The equivalent heating current will be 3.00 A, as there is no inverse component.
The trip time follows out of the formula:
⎛ I2heating − I2preload, rotor ⎞
⎛ (3.00)2 − (0)2 ⎞
⎟ = 1445
⎜
⎟ = 58.6 s
t trip = τ rotor ⋅ ln⎜ 2
.
⋅
ln
2
2 ⎟
⎜I
. )2 ⎠
⎝ (3.00)2 − 3 ⋅ (100
⎝ heating − k rotor ⋅ Iflc ⎠
After trip the thermal reserve can be set back to 100% by energizing the emergency restart input.
Checking the trip time (warm condition)
Now check the trip time with a preload of 80%. The preload current Ipreload,rotor can be calculated out of
the preload percentage θpreload,rotor. From:
θ th, rotor (t = ∞) =
k 2rotor ⋅ I2flc − I2preload, rotor
k 2rotor ⋅ I2flc
⋅ 100%
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
it follows:
θ preload,rotor =
I2preload,rotor
k2rotor
⋅ I2flc
⋅ 100%
⇒
Ipreload,rotor = k rotor ⋅ Iflc ⋅
θ preload,rotor
100%
=
3 ⋅ 100
. ⋅ 0.8 = 155
. A
Applying the preload current I = 1.55 A for a long time will eventually result in a steady state rotor
thermal reserve of 20%. For test purposes a higher current can be injected until the display value is 20%.
Starting from 20 % rotor thermal reserve, raise the symmetric three-phase current stepwise to I = 3.00 A.
The trip time will be:
⎛ (3.00)2 − (155
. )2 ⎞
⎟ = 137
t trip = 1445
. ⋅ ln⎜
. s
. )2 ⎠
⎝ (3.00)2 − 3 ⋅ (100
Checking the trip time characteristic
Inject the following symmetric three phase injecting currents and check the tripping times. Be sure the
thermal reserve is back at the initial value before each time measurement.
I (A)
1.80
2.50
3.00
3.50
4.00
4.50
ttrip (s)
ttrip (s)
preload = 0
preload = 80%
376.1
94.5
58.6
40.6
30.0
23.2
180.6
24.4
13.7
9.0
6.5
4.9
Checking the trip time with asymmetrical current
Start with cold condition (θth,rotor = 100%). Inject a asymmetric overload current by injecting only two
3
phases with Iphase =
⋅ 3.00 = 2.60 A (step function). This simulates the situation in which one phase of
2
a symmetric three phase current of 3.00 A is interrupted. The normal and inverse components are 1.50 A
then.
First the equivalent heating current is calculated.
I2heating = I2norm + k inv ⋅ I2inv = I2norm + 5 ⋅ I2inv = I2 = (150
. )2 + 5 ⋅ (150
. )2 = 135
.
The trip time follows out of the formula:
⎛ I2heating − I2preload, rotor ⎞
⎛ 135
. − (0)2 ⎞
⎟ = 1445
⎜
⎟ = 36.3 s
t trip = τ rotor ⋅ ln⎜ 2
.
⋅
ln
2
2 ⎟
⎜I
. − 3 ⋅ (100
. )2 ⎠
⎝ 135
⎝ heating − k rotor ⋅ Iflc ⎠
Checking the rotor cooling down time
Inject a symmetric three phase current of 3.00 A for 26.3 s. The stator thermal reserve will decrease to
50%. Then decrease the current to 1.22 A. The steady state stator thermal reserve will be 50% then:
26.3 ⎞
⎛
−
I2th, rotor (26.3) = (3.00)2 ⋅ ⎜1 − e 144.5 ⎟ = 150
.
⎟
⎜
⎠
⎝
θ th, rotor (26.3) =
⇒
I th, rotor = 122
. A
3.00 − 150
.
⋅ 100% = 50%
3.00
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
Now take away the current. The motor status will change to ‘STOPPED’, which means the rotor cooling
down factor will be incorporated. Check if the time to cool down to 75% is approximately 200 s:
θ th, rotor (t) =
3.00 − I2th, rotor
3.00
I2th, rotor (t cool down )
6.16.5
=
⋅ 100% = 75%
I2preload, rotor
⋅e
−
⇒
I2th, rotor = 0.75
t cool down
cstop,rot ⋅ τrotor
= 150
. ⋅e
−
t cool down
2.00 ⋅144.5
= 0.75
⇒
t cool down = 200.3 s
Testing the stator thermal overload protection
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
kstat
CHANNELS
L1
L2
L3
In
PROTECTIONS
THERMAL OVERLOAD
τ1,stat
τ2,stat
pweight
cstop,stat
θwarn
START INHIBIT
EMERGENCY RESTART
Setting
1.00 ⋅ In
ROTATING
1.10
For testing the stator thermal overload function a
single-phase test case is sufficient. Disable all
other protection functions. Marshall the thermal
overload protection to one of the output relays.
For test-purposes it is recommended to marshall
the emergency restart function to one of the
inputs, in order to be able to reset the stator
thermal reserve manually back to 100%.
ENABLED
ENABLED
ENABLED
1
ENABLED
100 s
200 s
.500
2.00
25%
ENABLED
ENABLED
Checking the steady state stator thermal reserve
Move to the menu part MEASURED VALUES (ON LINE) and select the menu part THERMAL RESERVE
STATOR on the display. Initially the displayed value will be 100% (Ipreload,stator = 0).
Inject a current I = 0.80 A in one of the phase leads. The stator thermal reserve will decrease. The steady
state value can be calculated out of the formulas for the stator thermal overload protection. The basic
iterative equation is:
t
t ⎞
⎛
−
−
τ
τ
I2th, stat (t) = I2preload, stator − I2 ⋅ ⎜ pweight ⋅ e 1,stat + (1 − pweight ) ⋅ e 2,stat ⎟ + I2
⎟
⎜
⎠
⎝
(
)
For t = ∞ the steady state value of the thermal stator current will be the injected current:
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
I2th, stator (t = ∞) = 0.64
The formula for the stator thermal reserve is:
θ th, stator (t) =
k 2stat ⋅ I2flc − I2th, stator (t)
k 2stator ⋅ I2flc
⋅ 100% =
(110
. )2 ⋅ (100
, )2 − I2th, stator (t)
(110
. )2 ⋅ (100
, )2
⋅ 100% =
121
. − I2th, stator (t)
121
.
⋅ 100%
The steady state thermal reserve will be:
θ th, stator (t = ∞) =
121
. − 0.64
⋅ 100% = 471%
.
121
.
Check if the displayed value for the stator thermal reserve decreases to 47.1%.
Checking the trip time (cold condition)
Check the trip time with cold condition (θth,stator = 100%). Inject an overload current I = 1.50 A (step
function).
The trip time follows out of the basic iterative equation for the thermal stator current Ith,stat. The trip
condition is:
I2th, stat (t trip )
=
k2stat
⋅ I2flc
=
(
I2preload, stator
2
−I
)
t trip
t trip ⎞
⎛
−
−
⎜
τ1,stat
τ2,stat ⎟
⋅ ⎜ pweight ⋅ e
+ (1 − pweight ) ⋅ e
+ I2
⎟
⎜
⎟
⎝
⎠
⇒
t trip
t trip ⎞
⎛
−
−
121
. = I2 ⋅ ⎜1 − 0.500 ⋅ e 100 − 0.500 ⋅ e 200 ⎟
⎜
⎟
⎝
⎠
By filling in different trip times the corresponding injecting current can be found. In this case the trip
time will be 108 s.
After trip the thermal reserve can be set back to 100% by energizing the emergency restart input.
Checking the trip time (warm condition)
Now check the trip time with a preload of 80%. The preload current Ipreload,stator can be calculated out of
the preload percentage θpreload,stator. From:
θ th, stator (t = ∞) =
k 2stat ⋅ I2flc − I2preload, stator
k 2stat ⋅ I2flc
⋅ 100%
it follows:
θ preload, stator =
I2preload, stator
k2stat
⋅ I2flc
⋅ 100%
⇒
Ipreload, stator = k stat ⋅ Iflc ⋅
θ preload, stator
100%
= 11
. ⋅ 100
. ⋅ 0.8 = 0.98 A
Applying the preload current I = 0.98 A for a long time will eventually result in a steady state stator
thermal reserve of 20%. For test purposes a higher current can be injected until the display value is 20%.
Starting from 20 % stator thermal reserve, raise the current stepwise to I = 1.50 A. The trip time will be
29 s.
Checking the trip time characteristic
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
Inject the following currents and check the tripping times. Be sure the thermal reserve is back at the
initial value before each time measurement.
Check via the MEASURED VALUES menu if the PRE-ALARM and ALARM LED indicators light up when
the stator thermal reserve reaches 25%.
ttrip (s)
ttrip (s)
I (A)
1.15
1.25
1.50
1.75
2.50
3.00
preload = 0
preload = 80%
381.9
217.3
107.7
69.0
29.0
19.4
167.2
73.6
29.0
17.0
6.5
4.2
Checking the stator cooling down time
Inject a current of 2.00 A for 22.1 s. The stator thermal reserve will decrease to 50%. Then decrease
the current to 0.78 A. The steady state stator thermal reserve will be 50% then:
22.1
22.1 ⎞
⎛
−
−
I2th,stat (221
. ) = (2.00)2 ⋅ ⎜1 − 0.500 ⋅ e 100 − 0.500 ⋅ e 200 ⎟ = 0.605
⎜
⎟
⎝
⎠
θ th, stator (221
.) =
⇒
Ith,stat = 0.78 A
121
. − 0.605
⋅ 100% = 50%
121
.
Now take away the current. The motor status will change to ‘STOPPED’, which means the stator
cooling down factor will be incorporated. Check if the time to cool down to 75% is approximately 193
s:
θ th, stator (t) =
121
. − I2th, stator
I2th, stat (t cool down)
121
.
=
⋅ 100% = 75%
I2preload, stator
⇒
I2th, stator = 0.3025
tcool down
tcool down
⎛
⎞
−
−
⎜
cstop,stat ⋅ τ1,stat
cstop,stat ⋅ τ2,stat ⎟
⋅ ⎜ pweight ⋅ e
+ (1 − pweight ) ⋅ e
⎟ =
⎜
⎟
⎝
⎠
tcool down
tcool down ⎞
⎛
−
−
= 0.605 ⋅ ⎜ 0.500 ⋅ e 2.00 ⋅100 + 0.500 ⋅ e 2.00 ⋅200 ⎟ = 0.3025
⎜
⎟
⎝
⎠
¡Error! Argumento de modificador desconocido.
⇒
t cool down = 192.5 s
G88700-C3527-07-7600
MFR 7SJ551
6.16.6
Operating instructions
Testing the thermal overload protection of non-rotating objects
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
k
CHANNELS
L1
L2
L3
In
PROTECTIONS
THERMAL OVERLOAD
TrueRMS
τ1
τ2
pweight
τadj
cadj
θwarn
Setting
For testing the thermal overload function a singlephase test case is sufficient. Disable all other
protection functions. Marshall the thermal overload protection to one of the output relays.
1.00 ⋅ In
NON-ROTATING
1.10
ENABLED
ENABLED
ENABLED
1
ENABLED
PHASE
100 s
200 s
.500
ENABLED
2.00
25%
Checking the steady state thermal reserve
Move to the menu part MEASURED VALUES (ON LINE) and select the menu part THERMAL RESERVE on
the display. Initially the displayed value will be 100% (Ipreload = 0).
Inject a current I = 0.80 A in one of the phase leads. The thermal reserve will decrease. The steady state
value can be calculated out of the formulas for the thermal overload protection. The basic iterative
equation is:
I2th (t)
=
(
I2preload
2
−I
)
t
t ⎞
⎛
−
−
τ1
τ2 ⎟
⎜
⋅ pweight ⋅ e
+ (1 − pweight ) ⋅ e
+ I2
⎜
⎟
⎝
⎠
For t = ∞ the steady state value of the thermal current will be the injected current:
I2th (t = ∞) = 0.64
The formula for the thermal reserve is:
θ th (t) =
k 2 ⋅ I2flc − I2th (t)
k 2 ⋅ I2flc
⋅ 100% =
(110
. )2 ⋅ (100
, )2 − I2th (t)
(110
. )2 ⋅ (100
, )2
⋅ 100% =
. − I2th (t)
121
⋅ 100%
.
121
The steady state thermal reserve will be:
θ th (t = ∞) =
121
. − 0.64
⋅ 100% = 471%
.
121
.
Check if the displayed value for the thermal reserve decreases to 47.1%.
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
Checking the trip time (cold condition)
Check the trip time with cold condition (θth = 100%). Inject an overload current I = 1.50 A (step
function).
The trip time follows out of the basic iterative equation for the thermal current Ith. The trip condition is:
I2th (t trip )
=k
2
⋅ I2flc
=
(
I2preload
2
−I
)
t trip
t trip ⎞
⎛
−
−
⎜
τ1
⋅ ⎜ pweight ⋅ e
+ (1 − pweight ) ⋅ e τ2 ⎟⎟ + I2
⎝
⎠
⇒
t trip
t trip ⎞
⎛
−
−
121
. = I2 ⋅ ⎜1 − 0.500 ⋅ e 100 − 0.500 ⋅ e 200 ⎟
⎜
⎟
⎝
⎠
By filling in different trip times the corresponding injecting current can be found. In this case the trip
time will be 108 s.
Checking the trip time (warm condition)
Now check the trip time with a preload of 80%. The preload current Ipreload can be calculated out of the
preload percentage θpreload. From:
θ th (t = ∞) =
k 2 ⋅ I2flc − I2preload
k 2 ⋅ I2flc
⋅ 100%
it follows:
θ preload =
I2preload
k
2
⋅ I2flc
⋅ 100%
⇒
Ipreload = k ⋅ Iflc ⋅
θ preload
100%
= 11
. ⋅ 100
. ⋅ 0.8 = 0.98 A
Applying the preload current I = 0.98 A for a long time will eventually result in a steady state thermal
reserve of 20%. For test purposes a higher current can be injected until the display value is 20%.
Starting from 20 % thermal reserve, raise the current stepwise to I = 1.50 A. The trip time will be 29 s.
Checking the trip time characteristic
Inject the following currents and check the tripping times. Be sure the thermal reserve is back at the
initial value before each time measurement.
Check via the MEASURED VALUES menu if the PRE-ALARM and ALARM LED indicators light up when
the thermal reserve reaches 25%.
I (A)
1.15
1.25
1.50
1.75
2.50
3.00
ttrip (s)
ttrip (s)
preload = 0
preload = 80%
381.9
217.3
107.7
69.0
29.0
19.4
167.2
73.6
29.0
17.0
6.5
4.2
Checking the adjustment factor
Inject a current of 2.00 A for 22.1 s. The thermal reserve will decrease to 50%. Then decrease the
current to 0.78 A. The steady state thermal reserve will be 50% then:
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
22.1
22.1 ⎞
⎛
−
−
I2th (221
. ) = (2.00)2 ⋅ ⎜1 − 0.500 ⋅ e 100 − 0.500 ⋅ e 200 ⎟ = 0.605
⎜
⎟
⎝
⎠
θ th (221
.)=
⇒
Ith = 0.78 A
121
. − 0.605
⋅ 100% = 50%
121
.
Now energize the binary tadj input. As the thermal reserve is in steady state this will have no influence.
Now take away the current. Check if the time to cool down to 75% is approximately 193 s:
θ th (t) =
121
. − I2th
⋅ 100% = 75%
121
.
I2th (t cool down )
=
I2preload
⇒
I2th = 0.3025
tcool down
tcool down ⎞
⎛
−
−
⎜
cadj ⋅ τ1
c ⋅τ ⎟
⋅ ⎜ pweight ⋅ e
+ (1 − pweight ) ⋅ e adj 2 ⎟ =
⎜
⎟
⎝
⎠
tcool down
tcool down ⎞
⎛
−
−
= 0.605 ⋅ ⎜ 0.500 ⋅ e 2.00 ⋅100 + 0.500 ⋅ e 2.00 ⋅200 ⎟ = 0.3025
⎜
⎟
⎝
⎠
6.16.7
⇒
t cool down = 192.5 s
Testing the ambient temperature biasing
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
k
PROTECTIONS
THERMAL OVERLOAD
AMBIENT TEMPERATURE
Tmax
Tmin
INPUT SENSOR
Setting
1.00 ⋅ In
NON-ROTATING
1.10
Disable all other protection functions.
Connect an RTD sensor simulator to input sensor
connection 1. The thermal protection will take
into account the simulated temperature by the
RTD simulator in determining the thermal reserve.
Refer to section 4.3 for a detailed description.
ENABLED
ENABLED
120 °C
40 °C
1
Simulate a temperature above 120 °C. Check if the thermal reserve is 0%.
Make sure the input currents are zero and there is no preload. Simulate a temperature of 20 °C.
c ambient =
Tambient − Tmin 2 2
20 − 40
⋅ k ⋅ Iflc =
⋅ (110
. )2 ⋅ (100
. )2 = −0.3025
Tmax − Tmin
120 − 40
I2th, ambient = I2preload + c ambient = −0.3025
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
θ th =
Operating instructions
k 2 ⋅ I2flc − I2th, ambient
k 2 ⋅ I2flc
⋅ 100% =
(110
. )2 ⋅ (100
. )2 + 0.3025
(110
. )2 ⋅ (100
. )2
⋅ 100% = 125%
Check if the thermal reserve in cold condition is 125%.
6.16.8
Testing the start inhibit
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Istart
tstart
nwarm
ncold
CHANNELS
L1
L2
L3
In
PROTECTIONS
THERMAL OVERLOAD
τ1,stat
τ2,stat
pweight
START INHIBIT
tinh
θstator
Marshall one of the output relays to the protection function start inhibit. Disable all other
protection functions.
Setting
1.00 ⋅ In
ROTATING
4.00 ⋅ In
10.0 s
2
3
ENABLED
ENABLED
ENABLED
1
ENABLED
999 min
200 s
1.00
ENABLED
5s
50.0%
Checking the rotor start inhibit
For testing the rotor thermal overload function a three-phase test case is required.
The rotor start inhibit level is calculated out of:
θ rotor =
I2start
k2rotor ⋅ I2flc
t
⎛
− start ⎞
(4.00)2
τ rotor ⎟
⎜
⋅ 1− e
⋅ 100% =
⎜
⎟
3 ⋅ (100
. )2
⎝
⎠
10.0 ⎞
⎛
−
⋅ ⎜1 − e 144.5 ⎟ ⋅ 100% = 357%
.
⎜
⎟
⎝
⎠
Inject the relay with a three-phase current of 3.00 A. Take away the current when the rotor thermal
reserve is smaller than 35.7%. Check if the start inhibit output relay closes. After cooling off again to a
thermal reserve of 35.7% the delay time of 5 seconds starts. Check this delay time.
Checking the stator start inhibit
Now change the stator thermal overload settings to:
Parameter
τ1,stat
τ2,stat
pweight
Setting
100 s
200 s
.500
For testing the stator start inhibit a single-phase test case is sufficient.
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Inject the relay with a current of 2.00 A. Take away the current when the stator thermal reserve is smaller
than 50.0%. Check if the start inhibit output relay closes. After cooling off again to a thermal reserve of
50.0% the delay time of 5 seconds starts, after which the start inhibit output is released again. Check this
delay time.
6.16.9
Testing the emergency restart
Parametrize the relay according to the settings of
the preceding section 6.16.8.
Enable the EMERGENCY RESTART function.
Marshall the EMERGENCY RESTART function to
one of the binary inputs.
6.16.10
Energize the binary emergency restart input.
Check if the rotor thermal reserve and the stator
thermal reserve are set back to 100%.
Testing the overtemperature protection
Parametrize the relay according to the following
settings.
Parameter
PROTECTIONS
OVERTEMPERATURE
ALARM 1
TRIP 1
ALARM 2
TRIP 3
ENABLED
70 °C
100 °C
70 °C
100 °C
ALARM 8
TRIP 8
70 °C
100 °C
6.16.11
Inject a current of 2.00 A and take away the
current when the stator thermal reserve is
smaller than 50%.
Setting
Marshall the OVERTEMPERATURE ALARM
condition to one of the output relays. Marshall
the OVERTEMPERATURE TRIP condition to one
of the other output relays. Disable all other
protection functions.
The tested sensor must be disconnected and
replaced by a RTD sensor simulator.
Check the performance of the overtemperature
protection by simulating different temperature
values. Check the alarm and trip level.
Testing the undercurrent protection
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Ino load
CHANNELS
L1
L2
L3
In
G88700-C3527-07-7600
Setting
1.00 ⋅ In
ROTATING
0.1 A
ENABLED
ENABLED
ENABLED
1
PROTECTIONS
UNDERCURRENT
tbypass
I<
t I<
ENABLED
5.00 s
.500
3.00 s
Marshall the UNDERCURRENT ALARM condition
to one of the output relays. Marshall the
UNDERCURRENT TRIP condition to one of the
other output relays. Disable all other protection
functions. For testing the undercurrent protection
a single-phase test case is sufficient.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
Checking the undercurrent protection for motors
When the motor status is ‘STOPPED’ or ‘START’
the undercurrent protection is inactive. Inject a
current higher than 1.125 A to change the motor
status from ‘STOPPED’ to ‘START’. Now lower
the current to 1.00 A. The motor status will
change to ‘RUNNING‘ and the bypass timer will
Checking the undercurrent protection for nonrotating objects
start. After 5 s the undercurrent protection will
be active.
Check the performance of the undercurrent
protection by injecting different current values.
Check the pick-up level and the delay time. Do
not lower the current under 0.100 A, as the
motor status will change to ‘STOPPED’ then.
Check the performance of the undercurrent
protection by injecting different current values.
Check the pick-up level and the delay time.
Change the device type to NON-ROTATING.
After changing the operating mode to ON LINE
the relay will pick-up. After injection of a current
higher than 0.500 A the pick-up condition will
vanish and the LED indicators can be reset.
6.16.12
Testing the low set overcurrent protection
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
L3
In
e
Ien
6.16.12.1
Setting
ENABLED
ENABLED
ENABLED
1
ENABLED
1
Marshall the LOW SET OVERCURRENT START
L> condition to one of the output relays. Marshall
the LOW SET OVERCURRENT TRIP L> condition
to a second output relay. Marshall the LOW SET
OVERCURRENT START e> condition to a third
output relay. Marshall the LOW SET
OVERCURRENT TRIP e> condition to a fourth
output relay. Disable all other protection
functions. For testing the low set overcurrent
protection a single-phase test case is sufficient.
Testing the definite time overcurrent protection
Parametrize the low set overcurrent protection
according to the following settings.
Parameter
PROTECTIONS
LOW SET OVERCURRENT
PHASE
CHARACTERISTIC
I>
tI>
EARTH
CHARACTERISTIC
Ie>
tIe>
Setting
ENABLED
DEFINITE
1.50 ⋅ In
5.00 s
ENABLED
DEFINITE
.500 ⋅ Ien
5.00 s
¡Error! Argumento de modificador desconocido.
For test currents below 6 x In (4 x In for
sensitive earth current input) , slowly increase
the test current over one phase and earth until
the protection picks up. For test currents above
6 x In (4 x In for sensitive earth current input)
measurement shall be performed dynamically.
Inject a test current of 1.00 x In via one phase
and the earth path. Check if the START e>
output picks up and if the TRIP e> output closes
after expiry of the delay time.
G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Inject a test current of 2.00 x In via one phase
and the earth path. Check if the START L>
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
output picks up and if the TRIP L> output closes
after expiry of the delay time.
Reset occurs at approximately 95% of the pickup value.
6.16.12.2
Testing the inverse time overcurrent protection
Parametrize the low set overcurrent protection
according to the following settings.
Parameter
PHASE
CHARACTERISTIC
Ip
tp
EARTH
CHARACTERISTIC
Iep
tep
Setting
ENABLED
NORMAL INVERSE
1.50 ⋅ In
1.00
ENABLED
NORMAL INVERSE
.500 ⋅ Ien
1.00
For test currents below 6 x In (4 x In for
sensitive earth current input) , slowly increase
the test current over one phase and earth until
6.16.12.3
Be aware that the parametrized times are pure
delay times; operating times of the
measurement functions are not included.
the protection picks up. For test currents above
6 x In (4 x In for sensitive earth current input)
measurement shall be performed dynamically.
Inject a test current of 1.00 x In via one phase
and the earth path. Check if the START e>
output picks up and if the TRIP e> output closes
after expiry of a delay time of 10.0 s. The
expected delay times can be calculated from the
formula given in the technical data.
Inject a test current of 2.00 x In via one phase
and the earth path. Check if the START L>
output picks up and if the TRIP L> output closes
after expiry of a delay time of 10.0 s.
Testing the custom curve overcurrent protection
Parametrize the low set overcurrent protection
according to the following settings.
Parameter
PHASE
CHARACTERISTIC
# OF POINTS
I1
tI1
Setting
ENABLED
CUSTOM
15
1.50 ⋅ In
100 s
I15
tI15
EARTH
CHARACTERISTIC
Ie1
tIe1
6.00 ⋅ In
.500 s
ENABLED
CUSTOM
0.50 ⋅ Ien
100 s
Ie15
tIe15
6.00 ⋅ Ien
.500 s
¡Error! Argumento de modificador desconocido.
Choose convenient current-time points for the
phase and earth custom curves.
For test currents below 6 x In (4 x In for
sensitive earth current input) , slowly increase
the test current over one phase and earth until
the protection picks up. For test currents above
6 x In (4 x In for sensitive earth current input)
measurement shall be performed dynamically.
Inject different test currents via one phase and
the earth path. Check if the START e> output
picks up and if the TRIP e> output closes after
expiry of the corresponding delay times. Check
if the START L> output picks up and if the TRIP
L> output closes after expiry of the
corresponding delay times.
G88700-C3527-07-7600
MFR 7SJ551
6.16.13
Operating instructions
Testing the high set overcurrent protection
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
L3
In
e
Ien
PROTECTIONS
HIGH SET OVERCURRENT
PHASE
I>>
tI>>
EARTH
Ie>>
tIe>>
Setting
ENABLED
ENABLED
ENABLED
1
ENABLED
1
ENABLED
2.00
.500 s
ENABLED
1.00 ⋅ Ien
2.50 s
Marshall the HIGH SET OVERCURRENT START
L>> condition to one of the output relays.
Marshall the HIGHHSET OVERCURRENT TRIP
L>> condition to a second output relay. Marshall
the HIGH SET OVERCURRENT START e>>
condition to a third output relay. Marshall the
HIGH SET OVERCURRENT TRIP e>> condition to
6.16.14
a fourth output relay. Disable all other protection
functions. For testing the high set overcurrent
protection a single-phase test case is sufficient.
For test currents below 6 x In (4 x In for
sensitive earth current input) , slowly increase
the test current over one phase and earth until
the protection picks up. For test currents above
6 x In (4 x In for sensitive earth current input)
measurement shall be performed dynamically.
Inject a test current of 1.50 x In via one phase
and the earth path. Check if the START e>
output picks up and if the TRIP e> output closes
after expiry of the delay time.
Inject a test current of 3.00 x In via one phase
and the earth path. Check if the START L>
output picks up and if the TRIP L> output closes
after expiry of the delay time.
Reset occurs at approximately 95% of the pickup value.
Be aware that the parametrized times are pure
delay times; operating times of the
measurement functions are not included.
Testing the unbalance protection
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Ino load
CHANNELS
L1
L2
L3
In
PROTECTIONS
UNBALANCE
tbypass
I2
t2p
G88700-C3527-07-7600
Setting
1.00 ⋅ In
ROTATING
0.1 A
ENABLED
ENABLED
ENABLED
1
ENABLED
1.00 s
.200
.200
Marshall the UNBALANCE ALARM condition to
one of the output relays. Marshall the
UNBALANCE TRIP condition to one of the other
output relays. Disable all other protection
functions. For testing the unbalance protection a
single-phase test case is sufficient, but best
results are achieved with a three-phase test case.
Checking the unbalance protection for motors
Inject a current higher than 1.125 A to change
the motor status from ‘STOPPED’ to ‘START’.
The bypass timer starts. Now lower the current
to 1.00 A. The motor status will change to
‘RUNNING‘ . During the bypass time the
unbalance protection is inactive. After 5 s the
unbalance protection will be active.
Check the performance of the unbalance
protection by injecting different asymmetric
currents. Check the pick-up level. Do not lower
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
the current under 0.100 A, as the motor status
will change to ‘STOPPED’ then.
Be aware that the unbalance protection function
calculates the delay time out of absolute values
and not out of relative values.
Example 1
I2p = 0.2 x In. The injected current is 1.00 x In.
The function picks up with 20% asymmetry.
Example 2
I2p = 0.2 x In. The injected current is 2.00 x In.
The function picks up with 10% asymmetry.
6.16.15
A convenient test is injecting 1.00 A in one
phase. The unbalance current will be 0.33 A
then, which leads to a trip delay time (extremely
inverse) of 9.0 s.
If the motor status is ‘START’ the unbalance
protection picks up with one third of the largest
phase current instead of with I2p. Check this pickup behaviour.
Checking the unbalance protection for nonrotating objects
Change the device type to NON-ROTATING. The
bypass time and the motor status dependent
behaviour do not apply. All further tests and
examples are valid.
Testing the locked rotor protection
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Ino load
Istart
CHANNELS
L1
L2
L3
In
PROTECTIONS
LOCKED ROTOR
tlr
Setting
1.00 ⋅ In
ROTATING
0.1 A
4.00 ⋅ In
ENABLED
ENABLED
ENABLED
1
Marshall the LOCKED ROTOR condition to one of
the output relays. Disable all other protection
functions. For testing the locked rotor protection
a single-phase test case is sufficient.
The locked rotor protection is only active for
motor status ‘START’. Check the performance of
the locked rotor protection by injecting different
current values higher than 1.125 A. Check the
delay times. A convenient injecting current is the
start current of 4.00 A. The locked rotor
protection should trip in the locked rotor time of
5.00 s then.
ENABLED
5.00 s
¡Error! Argumento de modificador desconocido.
G88700-C3527-07-7600
MFR 7SJ551
6.16.16
Operating instructions
Testing the zero speed protection
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Ino load
Istart
CHANNELS
L1
L2
L3
In
PROTECTIONS
ZERO SPEED
tZERO
6.16.17
Setting
1.00 ⋅ In
ROTATING
0.1 A
4.00 ⋅ In
ENABLED
ENABLED
ENABLED
1
ENABLED
10.0 s
Marshall the ZERO SPEED ALARM condition to
one of the output relays. Marshall the ZERO
SPEED TRIP condition to one of the other output
relays. Marshall the ZERO SPEED function to one
of the binary inputs. Disable all other protection
functions. For testing the ZERO SPEED protection
a single-phase test case is sufficient.
The ZERO SPEED protection is only active for
motor status ‘START’. Check the performance of
the ZERO SPEED protection by injecting a current
value of 4.00 A. Energizing the binary zero speed
input will cause the zero speed function to pick
up. If the binary input stays energized for 10.0 s
the zero speed function will trip. Check this
behaviour.
Testing the directional earth fault protection
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
e
Ien
Uin
Un
PROTECTIONS
LOW SET OVERCURRENT
EARTH
CHARACTERISTIC
Iφ>
tIφ>
DIRECTIONAL
EARTHFAULT
CONTROL
Ustrt
tUstrt
Iφ>
Iφ>>
φe
δ1
δ2
δ3
G88700-C3527-07-7600
Setting
ENABLED
ENABLED
ENABLED
1
ENABLED
100 V
ENABLED
DEFINITE
.500 ⋅ Ien
5.00 s
ENABLED
COSINE
0.1 ⋅ Un
8.5 s
FORWARD
FORWARD
0°
0°
0°
0°
Marshall the LOW SET OVERCURRENT START
φ> condition to one of the output relays. Marshall
the LOW SET OVERCURRENT TRIP φ> condition
to a second output relay. Marshall the HIGH SET
OVERCURRENT START φ>> condition to a third
output relay. Marshall the HIGH SET
OVERCURRENT TRIP φ>> condition to a fourth
output relay. Marshall the EARTH CURRENT
DIRECTION FORWARD condition to a fifth output
relay. Marshall the EARTH CURRENT DIRECTION
BACKWARD condition to a sixth output relay.
Disable all other protection functions. For testing
the directional earth fault protection a singlephase test case is sufficient.
The directional earth fault protection is tested in
a similar way as the low set earth overcurrent
time protection (section 6.16.12). But the
following must be observed.
The test current is injected on the sensitive earth
current input. Otherwise this function cannot
operate. This input is specially designed for
highly sensitive measurement. Thus, restricted
threshold values up to 1.4 A are available only.
The voltage which is needed for directional
determination is applied to the voltage input
(open delta voltage).
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
For directional determination the direction
indicator outputs can be useful. For any voltage
and earth current one of these two outputs will
close, indicating the forward or backward
direction. Be aware that these direction indicator
outputs are not the alarm or trip output!
conventional test sets, since the simulation of an
earth fault requires a complete displacement of
the voltage triangle. The correct relationship and
polarity of the measuring transformer
connections, essential for proper earth fault
detection, can only be tested when primary load
current is available during commissioning.
Testing of the earth fault protection for nonearthed networks is not completely possible with
6.16.18
Testing the undervoltage protection
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
Uin
Un
PROTECTIONS
UNDERVOLTAGE
U<
t U<
6.16.19
Setting
ENABLED
ENABLED
ENABLED
100 V
ENABLED
.250 ⋅ Un
5.00 s
Marshall the UNDERVOLTAGE ALARM condition
to one of the output relays. Marshall the
UNDERVOLTAGE TRIP condition to one of the
other output relays. Disable all other protection
functions. For testing the undervoltage protection
a single-phase test case is sufficient.
After changing the operating mode to ON LINE
the relay will pick-up. After applying a voltage
higher than 25.0 V the pick-up condition will
vanish and the LED indicators can be reset.
Check the performance of the undervoltage
protection by applying different voltage values.
Check the pick-up level and the delay time.
Testing the overvoltage protection
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
Uin
Un
PROTECTIONS
OVERVOLTAGE
U>
t U>
U>>
t U>>
Setting
ENABLED
ENABLED
ENABLED
100 V
ENABLED
.750 ⋅ Un
5.00 s
1.00 ⋅ Un
1.00 s
¡Error! Argumento de modificador desconocido.
Marshall the OVERVOLTAGE ALARM U>
condition to one of the output relays. Marshall
the OVERVOLTAGE TRIP U> condition to a
second output relay. Marshall the
OVERVOLTAGE ALARM U>> condition to a third
output relay. Marshall the OVERVOLTAGE TRIP
U>> condition to a fourth output relay. Disable all
other protection functions. For testing the
overvoltage protection a single-phase test case is
sufficient.
Check the performance of the overvoltage
protection by applying different voltage values.
Check the pick-up levels and the delay times.
G88700-C3527-07-7600
MFR 7SJ551
6.16.20
Operating instructions
Testing the breaker failure protection
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
L3
In
PROTECTIONS
LOW SET OVERCURRENT
PHASE
CHARACTERISTIC
I>
tI>
BREAKER FAILURE
PROTECTION
EXTERN
Ibf
tbf
Setting
ENABLED
ENABLED
ENABLED
1
ENABLED
DEFINITE
1.50 ⋅ In
5.00 s
ENABLED
DISABLED
.500 ⋅ In
10.0 s
Marshall the LOW SET OVERCURRENT TRIP
condition to one of the output relays. Marshall
6.16.21
the BREAKER FAILURE PROTECTION condition to
one of the other output relays. Disable all other
protection functions. For testing the breaker
failure protection a single-phase test case is
sufficient.
Checking the internal mode
Inject a current of 2.00 A. The low set
overcurrent protection will pick up. After 5.00 s
the low set overcurrent protection trips. Make
sure, however, that the current stays higher than
0.500 A. Check whether the breaker failure
protection output closes after 10.0 s.
Checking the external mode
Marshall the breaker failure protection function to
one of the binary inputs. Enable the external
mode of the breaker failure protection function.
Inject a current of 1.00 A. Energize the breaker
failure protection input. Check if the breaker
failure protection output closes after 10.0 s.
Testing the curve switch
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
Iflc
DEVICE TYPE
Ino load
CHANNELS
L1
L2
L3
In
PROTECTIONS
CURVE SWITCH
LOW SET OVERCURRENT
PHASE
CURVE 1
CHARACTERISTIC
I>1
tI>1
CURVE 2
CHARACTERISTIC
I>2
G88700-C3527-07-7600
Setting
1.00 ⋅ In
ROTATING
0.1 A
ENABLED
ENABLED
ENABLED
1
ENABLED
ENABLED
DEFINITE
1.50 ⋅ In
5.00 s
DEFINITE
3.00 ⋅ In
tI>2
0.50 s
Marshall the LOW SET OVERCURRENT START
L> condition to one of the output relays. Marshall
the LOW SET OVERCURRENT TRIP L> condition
to a second output relay. Disable all other
protection functions. For testing the curve switch
a single-phase test case is sufficient.
Checking the continuous mode
Parametrize the curve switch function according
to the following settings.
Parameter
CURVE SWITCH
MODE
Setting
ENABLED
CONTINUOUS
Marshall the curve switch function to one of the
binary inputs.
Inject a test current of 2.00 x In via one phase
lead. Check if the START L> output picks up
and if the TRIP L> output closes after expiry of
the delay time of 5.00 s.
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
Operating instructions
Energize the binary curve switch input. Inject a
test current of 2.00 x In via one phase lead.
Check if the relay stays in rest.
Inject a test current of 4.00 x In via one phase
lead. Check if the START L> output picks up
and if the TRIP L> output closes after expiry of
the delay time of 0.500 s.
Checking the pulse mode
Parametrize the curve switch function according
to the following settings.
Parameter
CURVE SWITCH
MODE
tCS
Setting
ENABLED
PULSE
10.0 s
Marshall the curve switch function to one of the
binary inputs.
Inject a test current of 2.00 x In via one phase
lead. Check if the START L> output picks up
and if the TRIP L> output closes after expiry of
the delay time of 5.00 s.
Energize the binary curve switch input just
before injecting a test current of 2.00 x In via
one phase lead. Check if the relay stays in rest
during 10.0 seconds after energizing the binary
input. Thus a transformer or motor inrush is
simulated.
¡Error! Argumento de modificador desconocido.
Repeat this test with a current of 4.00 A.
Check if the relay trips after 0.500 s.
Checking the status mode
Parametrize the curve switch function according
to the following settings.
Parameter
CURVE SWITCH
MODE
STATUS
Setting
ENABLED
STATUS
STP/STRT
Curve 2 will be active when the motor status is
‘STOPPED’ or ‘START’.
Move to the menu part MEASURED VALUES (ON
LINE) and select the menu part MOTOR STATUS
on the display. Check if the motor status is
‘STOPPED’.
Inject a test current of 2.00 A via one phase
lead. The motor status will change to ‘START’.
Check if the relay stays in rest.
Lower the current to 1.00 A. The motor status
will change to ‘RUNNING’. Curve 1 will be
active from now on.
Raise the current to 2.00 A again. Check if the
START L> output picks up and if the TRIP L>
output closes after expiry of the delay time of
5.00 s.
G88700-C3527-07-7600
MFR 7SJ551
6.16.22
Operating instructions
Testing the block function
Parametrize the relay according to the following
settings.
Parameter
DEVICE DATA
DEVICE TYPE
CHANNELS
L1
L2
L3
In
Uin
Un
PROTECTIONS
UNDERCURRENT
I<
t I<
UNDERVOLTAGE
U<
t U<
BLOCK
BLOCK I<
BLOCK U<
Setting
NON-ROTATING
ENABLED
ENABLED
ENABLED
1
ENABLED
100 V
ENABLED
.500
3.00 s
ENABLED
.250 ⋅ Un
5.00 s
ENABLED
ENABLED
ENABLED
higher than 25.0 V and a current higher than
0.500 A the pick-up condition will vanish and the
LED indicators can be reset.
Inject a test current of 1.00 x In via one phase
lead and apply a voltage of 100 V. Check if the
relay picks up when the current or the voltage is
taken away.
Inject a test current of 1.00 x In via one phase
lead and apply a voltage of 100 V. Energize the
binary block input. Check if the relay stays in
rest when the current or the voltage is taken
away.
Checking the pulse mode
Parametrize the block function according to the
following settings.
Parameter
BLOCK
MODE
tBLOCK
Setting
ENABLED
PULSE
10.0 s
As a test example here the block function will be
applied to the undercurrent and undervoltage
protection stages. Marshall the UNDERCURRENT
TRIP condition to one of the output relays.
Marshall the UNDERVOLTAGE TRIP condition to
a second output relay. Disable all other protection
functions. For testing the block function a singlephase test case is sufficient.
Marshall the block function to one of the binary
inputs.
This test shows how the block function can be
used to overcome the initial voltage- and
currentless condition of a transformer or motor.
Inject a test current of 1.00 x In via one phase
lead and apply a voltage of 100 V. Check if the
relay picks up when the current or the voltage is
taken away.
Checking the continuous mode
Parametrize the block function according to the
following settings.
Parameter
BLOCK
MODE
Setting
ENABLED
CONTINUOUS
Marshall the block function to one of the binary
inputs.
After changing the operating mode to ON LINE
the relay will pick-up. After applying a voltage
G88700-C3527-07-7600
After changing the operating mode to ON LINE
the relay will pick-up. After applying a voltage
higher than 25.0 V and a current higher than
0.500 A the pick-up condition will vanish and the
LED indicators can be reset.
Inject a test current of 1.00 x In via one phase
lead and apply a voltage of 100 V. Energize the
binary curve switch input just before taking
away the current or the voltage. Check if the
relay stays in rest during 10.0 seconds after
energizing the binary input.
Checking the status mode
The block status mode can be tested similar to
the curve switch status mode. It is applicable
only to rotating devices. Refer to 6.16.21.
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MFR 7SJ551
6.16.23
Operating instructions
Testing the external command
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
PROTECTIONS
EXTERNAL COMMAND
tEXT
6.16.24
Setting
ENABLED
ENABLED
ENABLED
5.00 s
Marshall the EXTERNAL COMMAND function to
one of the binary inputs. Marshall the EXTERNAL
COMMAND condition to one of the output relays.
Disable all other protection functions. For testing
the external command a test case is not
necessary.
Energize the binary external command input.
Check if the external command output closes
after 5.00 s.
Testing the circuit breaker position
Parametrize the relay according to the following
settings.
Parameter
CHANNELS
L1
L2
PROTECTIONS
CB POSITION
Setting
ENABLED
ENABLED
ENABLED
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Marshall the CIRCUIT BREAKER POSITION
function to one of the binary inputs. Marshall the
EXTERNAL COMMAND condition to one of the
LED indicators. Disable all other protection
functions. For testing the circuit breaker position
a test case is not necessary.
Energize the binary circuit breaker position input.
Check if the circuit breaker position LED indicator
lights up.
G88700-C3527-07-7600
MFR 7SJ551
6.17
Commissioning using primary tests
All secondary testing sets and equipment must
be removed. Reconnect current transformers.
For testing with primary values the protected
object must be energized.
!
Operating instructions
Warning
Primary tests shall be performed only by
qualified personnel which is trained in
commissioning of protection systems and
familiar with the operation of the
protected object as well as the rules and
regulations (switching, earthing, etc.)
6.17.2
Checking the reverse interlock
scheme (if used)
For use and tests of the reverse interlock
scheme it is necessary that one of the binary
inputs has been assigned to the block function.
Set the block function to continuous mode and
enable BLOCK I>>.
Binary inputs can be programmed ‘normally
open’ or ‘normally closed’. The following
procedure is valid for the ‘normally open mode’
as preset by the factory.
The protection relay on the incoming feeder and
those on all outgoing circuits must be in
operation. At first the auxiliary voltage for
reverse interlocking should not be switched on.
6.17.1
Current circuit checks
Connections to current transformers are
checked with primary values. For this purpose a
load current of at least 10% of the rated current
is necessary.
Currents can be read off on the display in the
front or via the serial interface and compared
with the actual measured values. If substantial
deviations occur, then the current transformer
connections are incorrect.
!
DANGER!
Secondary connections of the current
transformers must be short-circuited
before any current leads to the relay are
interrupted!
No further tests are required for overcurrent
time protection; these functions have been
tested under section 6.16.11. For checking the
trip circuits at least one circuit breaker live trip
should be performed (refer to section 6.17.4).
G88700-C3527-07-7600
Apply a test current which leads to pick-up of
the I>> stage as well as the I> or Ip stage.
Because of the absence of the blocking signal
the relay trips after the short delay time tI>>.
!
Caution
For the normal current circuits, test
currents larger than 6 times In may overload and damage the relay current input
channels if applied continuously. Observe
a cooling period if necessary.
Now switch on the DC voltage for the reverse
interlocking. The test as described above is
repeated, with the same result.
Simulate a pick-up on each protective device on
all outgoing feeders. Simultaneously, a shortcircuit is simulated on the incoming feeder (as
described before). Tripping now occurs after the
delayed time tI> or according to tp (calculated
delay time).
If applicable repeat test for the earth current
stages.
Simultaneously these tests prove that the wiring
between the protection relays is correct.
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MFR 7SJ551
6.17.3
Operating instructions
Testing the switching of
binary inputs and outputs
The relay contains a test routine with which the
binary inputs and outputs can be checked. This
test mode can only be entered in ON LINE
mode.
TEST MODE
ON LINE
!
Caution
As soon as the test mode is activated
the relays stops protecting the network
component.
The test mode can be reached in the ON LINE
main menu.
ENTER
Æ TESTMODE ?
ARE YOU SURE
?
After typing backspace the green ON LINE LED
indicator goes out to indicate there is no
protection.
ENTER
TESTMODE ?
TYPE
BACKSPACE
TEST MODE
PROTECTIONS
È
TEST MODE
I/O
TEST I/O:
Æ OUTPUTS
Choose the I/O test mode.
È
TEST I/O:
INPUTS
Checking the output relays
TEST I/O:
OUTPUTS
TEST OUTPUTS:
Æ OUTPUT 1
TOGGLE OUTPUT
Æ 1
ARE YOU SURE
?
TOGGLE OUTPUT
1
TYPE
BACKSPACE
Type BACKSPACE. Check if output 1 closes. By
repeating above procedure output 1 can be
opened again.
Follow this procedure for all available output
relays.
Checking the binary inputs
TEST I/O:
INPUTS
TEST OUTPUTS:
Æ INPUT 1
OFF
Energize input 1. Check if the indication ‘OFF’
changes to ‘ON’. Release input 1. Check if the
indication ‘ON’ changes to ‘OFF’.
Follow this procedure for all available binary
inputs.
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G88700-C3527-07-7600
MFR 7SJ551
Operating instructions
Leaving the test mode
TEST MODE
ON LINE test
LEAVE
Æ TESTMODE ?
ARE YOU SURE
?
LEAVE
TESTMODE ?
TYPE
BACKSPACE
After the I/O test it is important to leave the
test mode.
After typing backspace the relay is back in the
main menu of the protective ON LINE mode.
È
6.17.4
Tripping test including circuit
breaker
MFR 7SJ551 allows simple checking of the
tripping circuit and the circuit breaker. For this,
the circuit breaker can be tripped by initiation
from the operator keyboard. For this purpose
the ON LINE TEST function is used.
Refer to section 6.17.3 for a description of how
to close and open the trip command output.
Activate the CIRCUIT BREAKER POSITION
indication to scan the operation of the breaker
and the success of the procedure on a LED
indicator.
6.17.5 Putting the relay into
operation
All setting values should be checked again, in
case they were altered during the tests.
Particularly check if all desired protection and
ancillary functions have been enabled.
Stored indications on the front plate should be
reset by pressing the RI key on the front so that
from then on only real faults are indicated.
Check if the module is properly inserted and
fixed. All terminal screws - even those not in
use - must be tightened.
If a test switch is available this must be set in
the operating position.
Put the relay in ON LINE mode. The green ON
LINE LED indicator must light up. The red
MONITOR LED indicator has to be dark.
MFR 7SJ551 is ready for operation now.
G88700-C3527-07-7600
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MFR 7SJ551
Maintenance and trouble shooting
7
Maintenance and trouble shooting
7.1
General
Siemens digital protection relays are designed to
require no special maintenance. All measurement
and signal processing circuits are fully solid state
and therefore completely maintenance-free. Input
modules are static, relays are hermetically sealed
or provided with protective covers.
Only the internal real time clock module which
has an integrated battery back-up device may
have to be serviced after approximately 10 years
after manufacturing of the relay. We recommend
to replace the real time clock module in
accordance with your maintenance philosophy.
7.2
Routine checks
The planned maintenance intervals for checking
and maintenance can be used to perform
operational testing of the protection equipment.
This maintenance serves mainly for checking the
interfaces of the unit, i.e. the coupling with the
plant. The following procedure is recommended:
− Read-out of the operational values and
comparison with the actual values for
checking the analogue interfaces.
− Simulation of an internal short-circuit with 4 x
In for checking the analogue input at high
currents.
!
Caution
For the normal current circuits, test
currents larger than 6 times In, and for the
Ie sensitive current circuit, test currents
larger than 4 times In may overload and
damage the relay current input channels
if applied continuously. Observe a cooling
period if necessary.
− Circuit-breaker trip circuits are tested by
actual live tripping. The overcurrent function
can be tested by secondary injection of a
current (see section 6.16.12).
Don't forget to restore the settings to the original
ones, and to check the status of the current
terminals.
7.3
Self-test
One of the benefits of a microprocessor system
is the self-testing of the system. When a
malfunction is located, MFR 7SJ551 will record
the cause, if possible. The malfunction cause is
displayed in the manufacturing data menu (see
section 6.14.7). The ‘NO ERRORS’ message will
appear if MFR 7SJ551 has no failure messages.
An error message will appear if MFR 7SJ551 has
located an internal failure.
The meaning of the different error messages is:
!
Warning
Hazardous voltages can be present on all
the electrical circuits and components
connected with the supply voltage or
with the measuring and test test
voltages/currents! Non-observance of the
safety rules can result in personal injury
or property damage.
HW: AUX. SUPPLY
The auxiliary supply voltage was below the
allowed value for a certain time. Normal
operation will still be possible
HW: E2PROM
The EEPROM memory contains the default values
and the setting values. The test is carried out by
adding the data in the EEPROM and comparing
the sum values with fixed values. Contact the
Siemens service department if MFR 7SJ551 has
this failure.
HW: RAM
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
The RAM memory contains the actual values.
The test is carried out by write and read cycles in
order to verify that each bit in every location can
be modified under program control. Switch off
the auxiliary supply voltage and switch it on
again after a few seconds. Contact the Siemens
service department if the failure remains.
Instead of switching off the auxiliary supply
voltage you can also reset the microcontroller
with a fine pin on the front panel.
Maintenance and trouble shooting
If the real time clock (battery performance) is not
working properly, the ON LINE LED indicator will
start to flash. Only storing of statistical data will
be affected. The relay will perform all other
functions well.
7.4
Replacing the real time
clock module
HW: REF.VOLTAGE
The internal reference voltage is used for a
correct reading of all the analogue signals. A
failure of the internal reference voltage will cause
incorrect values in the system. Contact the
Siemens service department if MFR 7SJ551 has
this failure.
HW: ROM
The ROM memory contains the control program
and fixed data, which should not be changed.
The test is carried out by adding the data in the
ROM and comparing the sum values with fixed
values. Switch off the auxiliary supply voltage
and switch it on again after a few seconds.
Contact the Siemens service department if the
failure remains.
Instead of switching off the auxiliary supply
voltage you can also reset the microcontroller
with a fine pin on the front panel.
HW: TRIP COIL
A disconnection is observed in the circuit to
output relay number 1. Probably a trip command
activation of MFR 7SJ551 will not close the
contacts of output relay 1. Contact the Siemens
service department if MFR 7SJ551 has this
failure.
SW: MLFB
MFR 7SJ551 is equipped with a real time clock
module which should last for approximately 10
years. After this time the RTC chip must be
replaced. Malfunction of the real time clock is
indicated by a flashing ON LINE LED indicator.
Recommended RTC chip:
Manufacturer: DALLAS
Order number: DS 1286
This chip is mounted on the processor board and
is replaceable by anyone who is familiar with the
handling of electronic components.
For replacing the RTC chip the relay unit has to
be removed from its metal housing.
The RTC chip is located at the underside of the
relay to the backside next to the EPROMS (see
figure 7.1.
Replacement procedure:
− Prepare area of work; provide conductive
surface for the basic module.
− Open front cover.
There is a specific failure in the EEPROM which
has occurred between the last check of the
EEPROM and the check of the order number of
the 7SJ551 relay. Contact the Siemens service
department if MFR 7SJ551 has this failure.
− Note down all the settings (or check them
with the already filled-in form) or save them
on hard disk using the ‘7SJ551
Communication Utility’ software program.
SW: SW ERROR
− Prepare the RTC chip, do not place it on the
conductive surface.
There is an unexpected failure situation. Switch
off the auxiliary supply voltage and switch it on
again after a few seconds. Contact the Siemens
service department if the failure remains.
Instead of switching off the auxiliary supply
voltage you can also reset the microcontroller
with a fine pin on the front panel.
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!
Caution
Do not short-circuit the RTC chip! Do not
reverse the RTC chip polarities! Do not
G88700-C3527-07-7600
MFR 7SJ551
charge the RTC chip!
− Put the device in OFF LINE mode.
Maintenance and trouble shooting
− Switch on the device.
− Check if all settings are OK.
− Set the day and time as described in section
6.10.
− Switch of the device, and wait till the red
monitor LED has completely gone out.
− Place front cover.
− Unscrew, in the correct order, both screws on
the 7SJ551 relay.
7.5
!
Warning
Hazardous voltages can be present on all
the electrical circuits and components
connected with the supply voltage or
with the measuring and test
voltages/currents!
Non-observance of the safety rules can
result in personal injury or property
damage.
− Pull out the 7SJ551 basic module of the
housing with the handle, whilst supporting it
on the bottom-side.
!
Caution
Electrostatic discharges via the
component connections, the PCB tracks
or the connecting pins of the modules
must be avoided under all circumstances
by previously touching an earthed surface
and by connecting via an bracelet to a
high-ohmic discharge cord to earth.
Power failure test
The 7SJ551 relay has an internal power fail
detection circuit. To test this circuit, the
following steps have to be made:
− Make sure the 7SJ551 relay operates in the
ON LINE mode and start with decreasing the
supply voltage.
− When the supply voltage drops below its
specified operating range, MFR 7SJ551
ceases to operate. The relay has insufficient
voltage to continue to monitor the protected
device accurately. The green LED indicator ON
LINE will go out and the red LED indicator
MONITOR will light up. All output relays will
be in the power-off state.
− Switch off the supply voltage to zero. The red
LED indicator MONITOR will go out.
− Return the supply voltage to its normal
operating level. Verify that the 7SJ551 relay
resumes its normal ON LINE operation.
− Check the power fail memory circuit by
verifying that set points and statistical data
have not been altered.
− Place the 7SJ551 module on the conductive
surface.
7.6
− Remove the RTC chip with a pair of tweezers,
do not place it on the conductive surface.
− Insert the new RTC chip with a pair of
tweezers in the correct way.
When MFR 7SJ551 seems to have a defect,
various checks can be made by the user himself.
In case none of the LED indicators lights up when
turning on the mains supply, the following checks
can be performed:
Firmly push in the 7SJ551 module in its
housing, whilst supporting it on the bottom
side.
− Fasten the two screws in the correct order,.
G88700-C3527-07-7600
Trouble shooting
− Is the relay unit properly inserted in the metal
case, are both screws fastened?
− Is the auxiliary supply connected to the
correct input position (XC-IV-1 and XC-IV-2)?
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
− Is the connected auxiliary supply in
accordance with the 7SJ551 supply range?
Check the sticker at the top of the metal case.
− Is the mini-fuse in the power supply section
intact? If not, replace the fuse in accordance
with section 7.6.1.
When the red MONITOR LED indicator lights up
the internal memory might contain incorrect data.
Press the RES μC button with a small object.
MFR 7SJ551 will initialize its memory, and this
can lead to proper performance.
When MFR 7SJ551 seems to work properly (e.g.
the green ON LINE LED indicator lights up), but
does not respond to the keyboard functions, one
of the keys may be jammed by the metal front
during transportation or installation. Check all
keys by pressing them individually, and try to
move the metal front gently.
7.6.1
Maintenance and trouble shooting
!
Warning
Hazardous voltages can be present on all
the electrical circuits and components
connected with the supply voltage or
with the measuring and test
voltages/currents!
Non-observance of the safety rules can
result in personal injury or property
damage.
− Pull out the 7SJ551 basic module of the
housing with the handle, whilst supporting it
on the bottom-side.
!
Caution
Electrostatic discharges via the
component connections, the PCB tracks
or the connecting pins of the modules
must be avoided under all circumstances
by previously touching an earthed surface
and by connecting via an bracelet to a
high-ohmic discharge cord to earth.
Replacing the mini-fuse
For replacing the mini-fuse the relay unit has to
be removed from its metal housing. The fuse
screw holder is located at the backside of the
basis unit.
Replacement procedure:
− Select a replacement fuse. For an auxiliary
voltage of DC 24 - 60 V we recommend a 5 x
20 mm glass fuse, 1.6 A, slow. For an
auxiliary voltage of DC 110 - 250 V / AC 110
- 230 V we recommend a 5 x 20 mm glass
fuse, 0.5 A, slow.
− Prepare area of work; provide conductive
surface for the basic module.
Open front cover.
− Put the relay in OFF LINE mode.
Figure 7.1
− Switch of the device and wait till the red
MONITOR LED is completely off.
− Place the 7SJ551 module on the conductive
surface.
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Replacing the mini-fuse
G88700-C3527-07-7600
MFR 7SJ551
Maintenance and trouble shooting
− Remove blown fuse from the screw holder at
the middle in the back of the device (see
figure 7.1).
− Fit new fuse into the holder.
− Firmly push in the 7SJ551 module in its
housing, whilst supporting it on the bottomside.
− Fasten the two screws in the correct order.
Switch on the device again. If a power supply
failure is still signalled, a fault or short-circuit is
present in the internal power supply. The device
should be returned to the Siemens service
department.
G88700-C3527-07-7600
¡Error! Argumento de modificador desconocido.
MFR 7SJ551
8
Repairs
Repairs
Self-repair of defective modules is not
recommended, because specially selected
electronic components are used which must be
handled in accordance with the procedures
required for electrostatically endangered
components (EEC). Furthermore, special
manufacturing techniques are necessary for any
work on the printed circuit boards in order to
prevent damage of the bath-soldered multi-layer
boards, the sensitive components and the
protective finish.
Therefore, if a defect cannot be corrected by
operator procedure as described in Chapter 7, it
is recommended that the complete relay is
returned to the manufacturer.
It is unavoidable to replace individual modules, it
is imperative that the standards related to the
handling of electrostatically endangered
components are observed.
!
Warning
Hazardous voltages can be present on all
the electrical circuits and components
connected with the supply voltage or
with the measuring and test
voltages/currents!
Non-observance of the safety rules can
result in personal injury or property
damage.
!
Caution
Electrostatic discharges via the
component connections, the PCB tracks
or the connecting pins of the modules
must be avoided under all circumstances
by previously touching an earthed surface
and by connecting via an bracelet to a
high-ohmic discharge cord to earth.
Components and modules are not endangered as
long as they are installed within the relay.
assignment should be repeated. It is convenient
to save all parameters on hard disk or diskette
using the ‘7SJ551 Communication Utility’
software program. These can be transmitted into
the replacing relay.
We urgently advise to use a transport housing
for 7SJ55 relays that are sent back for repair.
Otherwise mechanical damages can occur.
A transport housing (order number G88700C3526-L153) is deliverable by Siemens
Netherlands:
The form ‘advice of return 7SJ55’ (Appendix E)
can be sent together with the defective relay.
Siemens Nederland N.V.
Industrial Centre Zoetermeer
Department PI PROD EPS (Room B3.0.17)
Werner von Siemensstraat 1
NL-2712 PN ZOETERMEER
The Netherlands.
Send or fax this form also to the purchase
department EV TD in The Hague, so that the
repair process can be prepared before the relay
arrives:
Siemens Nederland N.V.
Department EV TD
P.O. Box 16068
NL-2500 BB THE HAGUE
The Netherlands
fax number
31 70 333 3225
telephone number 31 70 333 3134
In this manner repair times can be minimized.
Be sure to fill in:
• sender data
• your order number
• MLFB code
• serial number
• firmware version
• error description
• desired action
• return address
Should it become necessary to exchange any
device or module, the complete parameter
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G88700-C3527-07-7600
MFR 7SJ551
9
Storage
Solid state protective relays shall be stored in
dry and clean rooms. The temperature range for
storage of the relays or associated spare parts
is -25 °C to +55 °C or -12 °F to 130 °F.
The relative humidity must be within limits to
avoid condensation or ice forming.
G88700-C3527-07-7600
Storage
After extended storage it is recommended that
the relay is connected to its auxiliary voltage
source for one or two days prior to taking it into
actual service. This serves to regenerate the
electrolytic capacitors of the auxiliary supply. In
extreme climatic conditions (tropics) prewarming will thus be achieved and
condensation avoided.
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