Capacitor/Filter-Protection
Relay CPR 04
Capacitor/Filterprotection Relay CPR 04
Introduction
The Trench CPR 04 is a comprehensive, numeric protection
relay, featuring:
• Operating mode software
selectable
(NORMAL / H-BRIDGE)
• RS232 serial data port at
the front
• Compact draw-out design
• Panel or 19 inch rack mounting
• Four software configurable
measuring elements
• Five configurable output relays
• Software selectable RS232
or RS485 serial data port at
the rear
• Time stamping function for
trip history and setting menu
Application
The CPR 04 provides comprehensive protection for the
capacitive, inductive and resistive elements of three phase
medium and high voltage
shunt capacitor banks and harmonic filter circuits.
The capacitor banks may have
a single star, double star, delta
or „H“ configuration, with
internally fused, externally
fused or unfused capacitor units.
• One self-supervision
output relay
• User configurable, to cater
for a wide range of relay
settings
2
A high performance
protection relay for capacitor banks
and harmonic filter circuits
NORMAL MODE - Protective functions
Peak repetitive
overvoltage protection
For each phase, CPR 04 determines the peak repetitive capacitor voltage using advanced
Digital Signal Processor (DSP)
techniques, by integrating the
measured line current waveform, to give a signal representing the voltage waveform applied to the capacitor bank.
The peak repetitive voltage of
this signal is then extracted,
and compared to adjustable
thresholds. For calculated peak
repetitive voltages above the
thresholds, a starter signal is
output, and the inverse time
ANSI capacitor temporary overvoltage withstand curve respectively adjustable definite timers
define the time before trip signals are output.
Thermal overcurrent
protection
For each phase, CPR 04 protects a capacitor bank / harmonic filter circuit from excess
thermal current stressing, by
modelling the thermal response
of the circuit to the rms heating current, Irms. A second
order thermal model and associated adjustable heating / cooling time constant is then used
to continuously calculate the
thermal current response lth, to
the rms heating current. Ith is
compared to adjustable thresholds, which are linked to adjustable definite timers. Trip signals are output, if the associated threshold is exceeded for
the definite time set.
Star point
unbalance protection
CPR 04 measures the star point
unbalance current, and calculates the fundamental frequency
component, Iub.
This can then be compensated,
in magnitude and phase angle
to zero, to enable detection of
further changes, in both
magnitude and phase angle,
(∅Iub). The magnitude is a
measure of the change in capacitance in any leg of a double
star capacitor bank arrangement, whereas the phase angle
indicates the leg in which the
change in capacitance has occurred.
The magnitude of (∅)Iub is continuously compared with adjustable thresholds, each with an
adjustable definite timer.
Trip signals are output, if the
associated thresholds are exceeded for the definite times set.
detecting changes in impedance
resulting from failures and
faults within the capacitor
bank / harmonic filter circuit.
These faults or failures invariably result in an unbalance in
the fundamental frequency
component of the line currents.
CPR 04 calculates the fundamental frequency line current
unbalance, Ilub, from the three
phase line currents. Ilub is continuously compared with adjustable thresholds each with an
adjustable definite timer. Trip
signals are output if the associated thresholds are exceeded
for the definite times set.
The sensitivity of line current
unbalance protection is
limited by the effect of supply
voltage unbalance on the line
currents. Nevertheless, line current unbalance protection is
useful as back-up protection to
star point unbalance protection.
Line current
unbalance protection
The monitoring of line current
unbalance provides a means of
3
NORMAL MODE - Protective functions
Earth fault protection
Undercurrent protection
CPR 04 calculates the fundamental frequency earth fault
current, Io , as the magnitude
of the vector sum of the three
phase line currents. Io is compared with adjustable thresholds each with an adjustable
definite timer. Trip signals are
output, if the associated thresholds are exceeded for the definite times set.
For each phase, CPR 04 calculates I1 , the fundamental frequency component of the line
current. I1 is continuously
compared with an adjustable
undercurrent threshold, I1<,
with an associated adjustable
definite timer. With the capacitorbank / harmonic filter circuit
breaker on, if the mains power
supply fails, as indicated by a
drop in I1 below I1< for longer
than the definite time set, then
the undercurrent trip signal
is output.
Fundamental frequency
overcurrent protection
For each phase, CPR 04 calculates the fundamental frequency component, I1 , of the line
current. I1 is continuously compared with adjustable thresholds each with an adjustable
definite timer. Trip signals are
output, if the associated thresholds are exceeded for the definite times set.
RMS overcurrent protection
For each phase, CPR 04 calculates the rms current, Irms ,
(fundamental + harmonics up
to the 50th). Irms is continuously
compared with adjustable
thresholds each with an adjustable definite timer.
Trip signals are output if the
associated thresholds are exceeded for the definite times set.
4
Breaker fail protection
If I1 remains above the undercurrent threshold for longer
than the adjustable definite
time after the breaker switches
off, or after a trip output signal
has been given by CPR 04,
then this indicates a failure of
the breaker, and the breaker
fail signal is output. This signal
can be used trip to an up-stream breaker.
Capacitor bank
discharge timer
CPR 04 provides the necessary
logic, and a breaker inhibit
output signal, Bena, to inhibit
the re-energization of the
capacitor bank / harmonic filter
circuit breaker, for an
adjustable definite time since
de-energization
Event Trip
CPR 04 provides the necessary
logic, to trip any of the output
relays via a change in the status
of the digital input.
H-BRIDGE MODE - Protective function
„H“ configuration
capacitor bank
unbalance protection
In an alternative user-configurable operating mode, CPR 04
provides fundamental frequency
„H“ configuration capacitor
bank unbalance protection
only. This provides sensitive unbalance protection independently for each phase of a capacitor bank.
For each phase the CPR04 calculates the fundamental component of the measured unbalance
current. The natural unbalance
of each phase can then be compensated in amplitude and phase
angle, to detect subsequent
changes. (∅a/b/c lub)
The unbalance current (∅)a/b/c
lub is then compared to adjustable thresholds, each with an
adjustable timer. Trip signals
are output, if the thresholds
are exceeded for the definite
times set.
5
Relay design
Measuring elements
Four current measuring elements
are provided within CPR 04.
The nominal current (1A/5A)
can be set in the menu.
Relay outputs
CPR 04 has six output relays.
The functionality of output
relays 1 to 5 is user configurable. The user may program the
relays to be manual or selfresetting, and to be normally
energized or de-energized
during the power-up healthy
condition. In addition, the user
may direct any of the binary
output signals of the protective
functions to output relays 1 to 5.
block. However, the user can
easily change the contacts of
the output relays to be as required by the application.
Auxiliary power supply
A high efficiency, low loss, wide
range AC/DC auxiliary power
supply is provided within CPR 04.
Special care has been taken to
minimize the overall standing
load of CPR 04 on the DC station batteries or AC busbar voltage supply.
The CPR 04 nominal auxiliary
power supply voltage is 30 250 V ac/dc. For the operative
range see technical specifications, page 10.
Time stamping
Output relay 6 is the self-supervision relay for CPR 04, and is
energized in the power-up,
normal condition, and de-energizes on loss of auxiliary power
supply, or on failure of CPR 04
internal power supply, microprocessor hardware, software
or memory.
CPR04 features a built in real
time clock which allows to time
and date stamp trip events as
well as modifications to settings and status registers. The
clock is backed up by a maintenance free supercap.
Serial data port
Contact forms
Output relays 1 to 6 each have
one change-over contact. As
default, all output relays are
supplied with the normally
open (relay de-energized)
contacts wired to the terminal
6
The RS232 port at the front
also allows for future firmware
upgrades as additional functions and features might be
added.
CPR 04 is provided with a
RS232 frontport and a softwareselectable RS232 or RS485
serial data port at the rear for
data communications between
an intelligent host device and
the protection relay.
The serial data port can be
used for the following purposes:
• Downloading of a set-up file
to a CPR 04.
• Uploading from a CPR 04 of
the set-up file currently
active within the relay.
• Uploading from a CPR 04 of
any error codes, or alarm
and trip annunciation
messages.
• The uploading from a CPR 04
of various instantaneous
parameters, measured and
calculated by the relay
during normal operation.
• Interconnection into a
SCADA system using
MODBUS RTU protocol
Relay design
LED indicators
Interactive configuration of
the protection relay
Three LED indicators are provided on the front panel of CPR
04, as follows:
• During testing:
Interactive self testing of the
protection relay
• Green LED:
This indicates that the auxiliary power supply is on, and
the self-supervision output
relay is energized, indicating
that the protection relay is
healthy.
• Yellow LED:
This indicates that one (or
more) of the „starter“
binary outputs signals of a
protection function is (are) at
logic 1 (high), and that the
protection relay may trip if
the condition persists.
• Red LED:
This indicates that a trip
condition has occurred
that has not yet been reset
and / or acknowledged.
LCD display
A two line, 16 character, full
alpha-numeric, back-lit, Liquid
Crystal Display (LCD) is provided on the front panel of CPR
04 for the following purposes:
• During normal operation:
The display of various measured and calculated
parameters, together with
• After failure:
Annunciation of any protection relay hardware, software or memory failures detected during self-testing of
the protection, by display of
the relevant error codes.
Test facilities
the low-set thresholds
associated with these
parameters.
• After a relay trip condition:
Annunciation of all the fault
conditions after a trip, including the value of the fault
currents and voltages at the
instant of trip, and the relay
trip time after occurance of
the fault condition.
• During relay configuration
and normal operation:
Display of the current and
voltage thresholds and timer
settings for each element, and
display of each output relay
configuration and check-sum.
• During relay configuration:
While CPR 04 is in service, it
continuously performs various
self-testing functions, and if
any errors or failures are detected, the corresponding error
code(s) will be displayed, and
the self-supervision output
relay will de-energize, to signal
the malfunction. These selftests include tests of the microprocessor, RAM, ROM and
EEPROM.
In addition, a further set of
hardware diagnostic tests may
be performed on the protection relay by the user, to test
and check the functionality of
the measurement offsets for
elements 1 to 4, the digital
input, relay outputs, keypad,
LCD display and LEDs.
7
Relay design
Housing and terminals
CPR 04 is housed in a draw-out
chassis within a fixed case. This
housing is particularly suitable
for both flush mounting and
19 inch rack mounting. The
case is designed for indoor use
in tropical climate and is designed to withstand shock, vibration and the ingress of dust
and moisture.
A terminal block, with 28 recessed terminals, is provided on
the fixed case. Standard screw
terminals, or fast-on connectors,
can be used on the terminal
block, for the external connections to the protection relay.
Withdrawing the protection
relay module automatically
short circuits the current transformer terminals.
Keypad
A five button key-pad is provided on the front panel of CPR
04 for the following purposes:
• Interactive configuration of
the protection relay
• Acknowledgment and
resetting of trip conditions
• Hardware diagnostic testing
8
PC based
software package
A Windows based software
package is available for CPR 04
to exploit its communication
facilities. This software package
enables the user to create, edit,
save, open and print any
number of CPR 04 set-up files
on a PC, and to download or
upload a set-up file to or from
a CPR 04, either directly or via
MODEM. In addition, all the
other facilities and functions of
the serial data port, as detailed
above, can be exploited using
this software package.
Digital input
CPR 04 is provided with an
optically isolated, binary
(on / off), voltage input channel.
Any voltage from 30 - 250 V
AC/DC applied to this input
channel will signal that the
input is active.
The functionality of the digital
input is depending on the
setting in the relevant menu.
General characteristics
Applicable standard
Operating temperature range
Storage temperature range
Humidity
Enclosure degree of protection
Shock and bump
Vibration
Power frequency voltage withstand
Impulse voltage withstand
Insulation resistance
Immunity to high frequency
disturbances
(1MHz burst disturbance test)
Immunity to electrostatic
discharges
(Electrostatic discharge test)
Immunity to fast transient bursts
(Fast transient burst test)
Immunity to high frequency
electromagnetic fields
Immunity to surge voltages
Immunity to voltage interruptions
Harmonics and flicker of main current
Conducted emissions
Radiated emissions
Nett Mass
Overall dimensions
IEC 60255 and EN 50263
-10 to +55 °C to IEC 60068-2-2
-20 to +70 °C to IEC 60068-2-2
4 days, 95% RH,
with temperature cycled between +25OC and + 45OC,
to IEC 60068-2-3
IP50 to IEC 60529
Shock: 15g, 3 pulses per direction, per axis. (total 18 times).
Bump : 10g, 1000 pulses per direction, per axis (total 6000 times).
To IEC 60255-21-2
9,8ms-2 (1g) constant frequency from 10 to 150 Hz per axis.
To IEC 60255-21-1
2 kV rms 50 Hz for 1 minute, from all terminals to case (earth),
and between terminals of independent circuits.
1,5 kV rms across open contacts of output relays.
To IEC 60255-5
5 kV peak, 1,2/50 µs waveshape, 0,5 J energy content,
10 shots in each polarity, between all terminals and case (earth),
and between terminals of independent circuits.
To IEC 60255-5
50 MΩ minimum at 500 VDC, to IEC 60255-5
2,5 kV peak between independent circuits, and to case (earth).
1 kV peak across terminals of the same circuit.
To IEC 60255-22-1
8 kV discharge in air
6 kV point contact discharge
To IEC 60255-22-2 and EN 50263
4kV supply lines / 2kV input & output lines /
1kV communication lines
To IEC 60255-22-4 and EN 50263
10 V / m, 100% PM, at 900 MHz
10 V, 80% AM, from 150 kHz to 80 MHz as well as
10 V / m, 80% AM, from 80 MHz to 1000 MHz, to EN 50263
2kV peak common / 1kV peak differential
To EN 61000-4-5 and EN 50263
230 VAC – 100% interruption – 200ms
110 VDC – 100% interruption – 50ms
To EN61000-4-11
To EN 61000-3-2
To EN 50263, from 150 kHz to 30 MHz.
To EN 50263, from 30 MHz to 1000 MHz.
3 kg
103(w) x 177(h) x 248(d)
9
Technical specifications
Auxiliary power
supply
Output relays
Quantity
Nominal rated current, In
Continuous current
Short time current
Burden
Accuracy of measurement
Nominal rated voltage, Vx
Operative range AC / DC
Burden with DC supply
Burden with AC supply
Quantity
Contact form (per relay)
Load
K1
Rated load
K2, K3, K4, K5, K6
Max. operating voltage
Rated load
Digital input
channel
Pushbuttons
Display
Indicators
Serial data port
Real Time Clock
10
Rated carry current
Max. operating voltage
Min. permissible load
Quantity
Function
Isolation
Type
Function
Type
Type
Screen Size
Character height
Type
Function
Quantity
Isolation
Frontport type
Rearport type
Baudrate (kBd)
Functionality
Accuracy
Backup
4
1A or 5A selectable in the software
15A
300A for 1s
<40mΩ
+/- 2% of nominal rated current
30 – 250V AC / DC
40 - 250V AC / 30 - 300V DC
<14W with all relays and back-light ON
<24VA with all relays and back-light ON
Alarm / trip relays: 5
Self-supervision relay: 1
1 – changeover contact (form C), user configurable
as N/O or N/C
Resistive load:
Inductive load:
(cos ␸ = 0,4 L/R = 7 ms)
(cos ␸ = 1)
5A at 250 VAC
3,5A at 250 VAC
1A at 220 VDC
0,8A at 220 VDC
3A at 110 VDC
2A at 110 VDC
5A at 48 VDC
4A at 48 VDC
380VAC, 250 VDC
5A at 250 VAC
3,5A at 250 VAC
5A at 30 VDC
2,5A at 30 VDC
5A
380VAC, 125 VDC
100mA at 5 VDC
1
Breaker on; Remote reset; Event trip
Optically isolated
30 – 250V AC / DC voltage input
>, <, ^, , and ACCEPT (red)
Miniature spring loaded manual pushbuttons
Back-lit Liquid Crystal Display (LCD),
with full alpha-numeric character set
16 character x 2 line
4mm
Light Emitting Diodes (LEDs)
Green : POWER ON / HEALTHY
Yellow : START (ALARM)
Red
: TRIP
2
Optically isolated
RS232 via DB9 socket
RS232 or RS485 – selectable in the software
2.4 up to 115.2 for each port seperatly selectable
Date; Weekday; HH:MM:SS
+/- 30 s per month
Supercap (>14 days without power)
^
Measuring
elements
Block diagram
11
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Änderungen vorbehalten
04.09
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