Sectos NXA
SF6 gas insulated pole mounted load-break
switch-disconnector
Technical Brochure
ABB Power Distribution
1
NXA 1 GB
Sectos NXA
SF6-gas insulated, pole mounted
load-break switch-disconnector
Index
2
NXA 1 GB
1
Sectos NXA, SF6 gas insulated, pole mounted,
switch-disconnector ....................................................................... 3
2
Use of Sectos NXA switch-disconnector ......................................... 4
3
Technical data ................................................................................. 5
3.1 Type code ............................................................................. 5
3.2 Standards .............................................................................. 5
3.3 General technical values ....................................................... 6
3.4 Electrical performance data .................................................. 6
3.5 Electrical endurance ............................................................. 7
3.6 Gas pressure temperature variation curve ............................ 7
3.7 Rating plate IEC ................................................................... 7
3.8 Rating plate ANSI .................................................................. 7
4
Accessories ..................................................................................... 8
4.1 Accessories to be installed in the mechanism end box ......... 8
4.2 Mounting accessories ......................................................... 11
4.3 Connecting bare conductor ................................................. 13
4.4 Connecting insulated cable ................................................. 13
4.5 Operating devices ............................................................... 14
4.6 Remote control .................................................................... 16
4.7 Indication of faults ............................................................... 17
5
Dimension drawings ...................................................................... 18
5.1 Sectos NXA switch-disconnectors ...................................... 18
5.2 Manual operating device ..................................................... 19
5.3 Motor operating device........................................................ 19
5.4 Mounting brackets ............................................................... 20
5.5 Terminals ............................................................................ 21
5.6 Crossarm ............................................................................ 22
6
Connection diagrams .................................................................... 23
6.1 Main circuit diagram of Sectos NXA ................................... 23
6.2 Auxiliary circuit diagram of the switch equipped with
single spring type actuator .................................................. 23
6.3 Auxiliary circuit diagram of the switch equipped with
double-spring type actuator................................................. 24
6.4 Down-lead cable plug .......................................................... 24
6.5 Connection of current sensors to fault indicator .................. 25
ABB Power Distribution
Sectos NXA
SF6-gas insulated, pole mounted
load-break switch-disconnector
Rating
plate
The insulators are made of flexible silicon
rubber, which if necessary are detachable.
Silicon rubber has excellent electrical
properties, is hydrophobic and unbreakable.
Outer cone bushing, series 400.
Earthing
terminal
Multi-pin plug-in terminals,
including the gas pressure
alarm circuit.
Gas filling
valve
Tank is made of stainless steel.
Clear, unambiguous, reliable position
indicator, made of light reflecting
material, visible from ground level
even at night in driving rain.
The tank fulfils the requirement
of "sealed pressure system" of
the standard IEC 56, which
means that during the expected
lifetime of the switch there
should not be any need to
add gas.
1 Sectos NXA
SF6-gas insulated,
pole mounted,
switch-disconnector
The sturdy load-break switch-disconnector is located inside a stainless steel tank, where it is completely
protected against the effects of environment.
Inside the tank SF6 gas is used as
insulating and arc extinguishing medium. SF6 gas improves the breaking
and making characteristics of the
switch, reducing the insulation distances between live parts and the
overall outer dimensions. The gas
pressure is 1,5 bar (abs.) at 20 oC,
see diagram 3.6 for the pressure/
temperature variation.
Inside of the tank there is a gas density indicating contact, which operates, when gas pressure drops
below 1,1 bar (abs.) at 20 oC.
ABB Power Distribution
Closed
The contact is wired to outside of the
tank via a multi-pin terminal plug,
from which the signal can easily be
transmitted to a remote control system.
The bushing insulators are outer
cone type, series 400 (DIN 47636ASL-36-400), on the top of which
are usually installed silicon rubber
outer insulators, which permit the
switch to be directly connected to an
overhead-line equipped with bare
conductors. Alternatively, a cable
termination with series 400 Teeconnector can be used to connect an
insulated cable directly to the outer
cone bushings.
Open
The mechanism is of the independent spring type ensuring the speed
of opening and closing to be independant of the speed of operation.
The Sectos NXA switch-disconnectors may be manually operated
or motor operated for remote control.
NXA switch-disconnectors are available for rated voltages 24 kV and
36 kV to IEC standards (IEC 129,
IEC 265-1), and for rated maximum
voltages 27 kV and 38 kV to ANSI
standards.
The position indicator, located in
the operating mechanism end box,
shows clearly and unambiguously
the position of the switch. The indicator is rigidly connected to the main
shaft of the switch and fulfils the
requirements of the standards IEC
129 A2 (1996) and NF C 64-140
(1990).
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NXA 1 GB
Sectos NXA
Use of Sectos NXA switch-disconnector
2
Use of Sectos NXA
switch-disconnector
The Sectos NXA switch-disconnectors are intended for
use as line switches in medium voltage overhead line
networks. They are designed for flexibility and are suitable for application on remote control systems.
The objective is to reach the highest possible reliability
in many types of difficult environments. Sectos NXA
switch-disconnectors are highly resistant to corrosion,
the effects of snow, ice, animals, vegetation and
vandalization giving superior performance, when compared with conventional air insulated switches.
Portal pole, installation below the crossarm,
manual operating device
The construction of Sectos NXA switch-disconnectors
strives to acheive maximum flexibility, and with various
mounting accessories allows easy installation.The
manual operating device can be upgraded with motor
operating mechanism, or vice versa, if the remote control
configuration in the network so demands. All accessories
needed for remote control, such as current sensors, fault
current indicators, remote control terminals, auxiliary
contacts etc. are designed to be easily retrofitted.
The Sectos NXA switch-disconnector is small, lightweight and can be fitted above or below the crossarm.
The operating rod can be cut to any desired length
allowing the operating device to be installed near the
groung level or higher up in the pole. Both the manual
and motor operated units are using similar fixed type
operating rod, and both can be padlocked in open and
closed position. For further information please refer
to the point 4.5.
Installation below the crossarm,
motor operating device
The Sectos NXA switch-disconnector requires a minimal
amount of maintenance. Stainless steel tank, hot dip
galvanised fixing accessories, carefully encapsulated
mechanism end box, silicon rubber outer insulators
and all main electrical parts located inside the SF6-gas
compartment together ensure a long and virtually
maintenance free service life. The only maintenance
operation would be the verification of the gas pressure,
which is recommended once every three years. In automated distribution systems the gas density alarm contact
can be used to give remote low gas alarm.
Installation above the crossarm,
motor operating device
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ABB Power Distribution
Sectos NXA
Technical data
3.
Technical data
3.1 Type code
NX A 24 C 630 A 1 – A1, 3, 5 : B2 : C4 : X
Pole mounted SF6 insulated switch-disconnector
Construction letter
Rated voltage
– 24 kV
– 36 kV
– 27 kV
– 38 kV
Type of insulator
– C silicon rubber insulator
– E outer cone insulator, series 400, thread M16
Rated current (A)
Spring device
– A 1-spring mechanism
– B 2-spring mechanism
Version
Code for accessories
3.2 Standards
The Sectos NXA switch-disconnector is designed to IEC standards, but the main electrical values have been tested
also according to ANSI standards.
IEC 129
Alternating current disconnectors and earthing switches
IEC 265-1
High-voltage switches. Part 1: High-voltage switches for rated voltages
above 1 kV and less than 52 kV
IEC 694
Common clauses for high-voltage switchgear and controlgear standards
ANSI/IEEE C37.63
IEEE Standard requirements for overhead, pad-mounted, dry-vault, and
submersible automatic line sectionalizers for AC systems
ANSI/IEEE C37.71
Three-phase, manually operated subsurface load-interrupting switches for
alternating-current systems
3.3 General technical values
– mechanical endurance more than 5000 close–open operations
– SF6 gas filling pressure (at 20 oC) 1,5 bar (abs.)
– weight 95 kg, complete for installation with silicon rubber insulators
– protection degree of the mechanism end box IP X7
– ambient temperature range –40...+60 oC
– creepage distance of the silicon rubber insulator (type NXAZJ 1) 960 mm
ABB Power Distribution
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Sectos NXA
Technical data
3.4 Electrical performance data
Standards : IEC
NXA 24
NXA 36
24 kV
36 kV
50 kV
60 kV
70 kV
80 kV
125 kV
145 kV
170 kV
195 kV
Insulation level
– rated voltage
– withstand voltage, 50 Hz
– between phases and against earth
– across the isolating distance
– lightning impulse withstand voltage
– between phases and against earth
– across the isolating distance
Current ratings
– rated normal current
– mainly active load breaking current (400 CO operations)
– closed loop breaking current
– line-charging breaking current
– cable-charging breaking current
– no-load transformer breaking current
– capacitor bank breaking current
– cable or line breaking current under earth fault conditions
– earth fault breaking current
Short circuit ratings
– short-time withstand current, Ith
– peak withstand current, Idyn
– short-circuit making current, peak value
630 A
630 A
630 A
50 A
50 A
20 A
200 A
87 A
200 A
400 A
400 A
630 A
40 A
40 A
20 A
175 A
80 A
175 A
16 kA, 3 s
40 kA
40 kA
10 kA, 3 s
25 kA
25kA
Standard: ANSI
NXA 27
NXA 38
25 kV
27 kV
600 A
150 kV
34,5 kV
38 kV
600 A
150 kV
60 kV
50 kV
78 kV
70 kV
60 kV
103 kV
19 kV
16,4 kV
26 kV
23 kV
600 A
1320 A
40 A
40 A
20 A
175 A
600 A
1320 A
40 A
40 A
20 A
175 A
16 kA
10 kA
10 kA
3,5 kA
16 kA
10 kA
10 kA
3,5 kA
Insulation level
– nominal voltage class
– rated maximum voltage
– rated continuous current
– rated impulse withstand voltage
Industrial frequency withstand voltage test
– 1 min, dry
– 10 s, wet
– DC, 15 min, withstand
Partial discharge measurements
– extinction voltage
– radio interference voltage
Breaking tests
– rated continuous and load-interrupting current
– symmetrical interrupting current
– line charging breaking current
– cable charging breaking current
– no-load transformer breaking current
– capacitor bank breaking current
Short-time and making current tests
– short-time current, asymmetrical, rms.
– short-time current, 1 s, symmetrical
– short-time current, 3 s, symmetrical
– short-time current, 10 s, symmetrical
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ABB Power Distribution
Sectos NXA
Technical data
3.5 Electrical endurance
NXA 24 (IEC), NXA 27 (ANSI)
NXA 36 (IEC), NXA 38 (ANSI)
Number of CO
operation cycles
Number of CO
operation cycles
5000
5000
1000
1000
100
100
10
10
100 A
10 A
1000 A
10 A
Load current,
cos j > 0,7
Load current,
cos j > 0,7
100 A
1000 A
3.6 Gas pressure / temperature variation curve
Pressure / bar
1,6
1,4
1,2
-40 °C
0 °C
-20 °C
Gas temperature / oC
20 °C
3.7 Rating plate IEC
ABB Transmit Oy
ABB Power Distribution
40 °C
3.8 Rating plate ANSI
ABB Transmit Oy
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Sectos NXA
Accessories
4
Accessories
4.1 Accessories to be installed
in the mechanism end box
961014
Single spring mechanism
Single spring mechanism
Usually Sectos NXA switch-disconnector is equipped with a single spring
mechanism. This kind of spring mechanism is suitable for most applications.
When the operating shaft of the switch is turned by manual or motor
operating device, the spring charges during the first part of the movement,
releases in the last part of the movement, and turns the switch abruptly to
the new position. Therefore the switch operates for opening and for closing
with the speed, which is completely independent from the operator or from
the operating device (quick make – quick break principle). Depending on
the type of the motor operating device, the motor operated switch opens
between 1...5 seconds from the command signal initiation.
961013
Double spring mechanism
Double spring mechanism
A
B
Sectos NXA switch-disconnector can be equipped, with a double-spring
mechanism for rapid opening from initiation. When the operating shaft
of the switch is turned from open position towards the closed position, the
closing spring charges during the first part of the movement, releases in the
last part of the movement, and turns the switch to the closed position. The
second spring, the opening spring, remains in charged position. The operating shaft is then turned, just a little, towards to the open position, the
opening spring releases and turns the switch to the open position. This
tripping to open can also be achieved by means of a tripping coil. When the
operating shaft is then turned completely to the open position, the opening
spring is charged again, and it remains in charged position during the next
closing.
Tripping coil
UEJBZB2 _
961015
The tripping coil is installed in the factory to the double-spring mechanism,
and the tripping circuit is connected to the multi-pin plug-in terminal, see
connection diagram 6.3. The total opening time of the switch-disconnector
with tripping coil is less than 0,1 s.
Tripping coil
UEJBZB 2/24V DC
Tripping coil
Nominal voltage
– 12 VDC
– 24 VDC
– 48 VDC
– 60 VDC
– 110 VDC
– 110 VAC
– 220 VDC
– 230 VAC
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Sectos NXA
Accessories
Auxiliary contacts
Main contact of NXA
Change-over contact
open
NXAZK 3
Auxiliary contacts for reliable position indication can be installed in the
mechanism end box. The normal switch can have 3 change-over contacts.
If the tripping coil is used simultaneously, one of these contacts is occupied
by the tripping circuit. The auxiliary contacts will be wired to the multi-pin
plug-in terminal, see connection diagrams 6.2 and 6.3.
closed
Auxiliary contacts
Multi-pin plug-in terminal
NXAZH 10 M
In every Sectos NXA switch-disconnector, there is always a 10 pin weather
proof plug-in terminal fitted to the body of the switch. It is intended for the
connection of the wiring of the gas density indicator, the position indicating
auxiliary contacts and the tripping coil to the remote control terminal or to the
motor operating device. Pins 1 and 6 are always used for the gas density
alarm contact or the alarm contact of the “gas low” blocking device.
Multi-pin terminal
Plug
NXAZH 10 F _
As an option there is available a remote end plug for the command cable.
If the customer prefers, the command cable can be connected to the plug in
the factory, in which case the length of the command cable must be advised
when ordered. See the connection diagram of the plug at 6.4.
NXAZH 10 F __
Type of the plug
Length of the cable (m)
Plug
The cable is suitable for outdoors, it is screened and provided with 1,5 mm²
flexible conductors.
Markings of the position indicator
3603
3604
Standard markings
3649
YKLW _
The position indicator of the switch-disconnector Sectos NXA fulfils the
requirements of the standards IEC 129 A2 (1996) and NF C 64-140 (1990),
which determine the requirements for the reliability of such an indicator.
The colours chosen and the markings are such that the position of the switchdisconnector is clearly visible even in bad weather conditions.
3604
3663
3662
Optional markings
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Sectos NXA
Accessories
Gas density indication
1
6
As a standard accessory in Sectos NXA switch-disconnectors there is a
temperature compensated alarm device, which is wired to the multi-pin
plug-in terminal. Please refer to diagrams 6.2 or 6.3.
The alarm contact 1-6 is normally closed (NC) and it opens, if the gas
pressure in the tank falls below 1,1 bar at 20 °C. This is a proven reliable
system for giving an alarm to the remote control system. When the switch is
used with manual operation device, the alarm signal circuit can be cabled
down to ground level for checking.
Gas density indication
Gas density gauge
NXAP 3
As a factory installed optional accessory for Sectos NXA switch-disconnector
there is available a gas density gauge, an instrument indicating the inside
gas pressure.
Gas density gauge
The gauge is temperature compensated, and it shows the pressure
difference between the inside of the tank and its internal reference
pressure. Variation of the outside air pressure does not affect the indication
of the gauge. Therefore is actually showing the density of the SF6 gas
inside of the tank. The gauge is installed below the switch tank, in the place
of the of the cap of the refilling valve.
Low gas lock-out
Gas Low
Low gas lock-out
NXAP 2
As an option for Sectos NXA switch-disconnector there is available a
blocking device, which blocks the operation of the operating mechanism by
means of a mechanical latch, released when the inside gas pressure
reduces. As the lock-out mechanism operates, an indication sign becomes
visible through the position indicator window giving low pressure indication.
The gas low lock-out mechanism is installed in the factory and it replaces
the standard density indicating alarm contact. The blocking device is fitted
with an auxiliary contact, which gives indication of the operation of the
device.
The low gas lock-out mechanism is recommended to be used with manually
operated switches only, and in installation places, where the outside
temperature never falls below -10 °C and the altitude doesn’t exceed
1000 m above sea level.
Operation counter
In each Sectos NXA switch-disconnector there is a mechanical operation
counter installed inside of the mechanism end box to help estimate of the
remaining service life of the switch.
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Sectos NXA
Accessories
4.2 Mounting accessories
All parts are of hot dip galvanised steel. The fixing elements described
here are suitable for wooden poles, but there are also fixing devices available,
which are specially designed for concrete and steel poles, etc. Please contact
ABB if special fittings are needed.
Mounting brackets
Installation below the crossarm
NXAM _
The switch-disconnector Sectos NXA is easy to install below or above
the crossarm using these brackets. The type NXAM 1 is included in the
delivery as a standard accessory. For other sizes of brackets for different
crossarms, please refer to the point 5.4.
Crossarm
NPTRN
The standard crossarm is 80 x 80 mm square tube. There are two standardised lengths, 2000 mm and 2850 mm. See dimension drawings at the
point 5.6.
Installation above the crossarm
Clossarm
Diagonal supports and fastenings for crossarm,
1-pole mounting
OJUPZK 9
The set includes all necessary parts for fixing the crossarms to a wooden
pole.
1-pole mounting
Crossarm
Fastenings for crossarm
2-pole mounting
OJUPZK 8
The set includes all necessary parts for fixing one end of the crossarm
to a wooden pole. For 2-pole installation 2 sets are needed.
2-pole mounting
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Accessories
Earthing clamp for the crossarm
NPTMS 8
The connector of the earthing clamp is suitable for 16 – 63 mm2 Cu
conductors.
Earthing clamp for
the crossarm
The switch-disconnector Sectos NXA can be earthed in two different ways:
either it can be earthed directly by connecting the earthing conductor
to the earthing terminal of the switch itself, or indirectly through crossarm
using this earthing clamp. The switch and the crossarm need not both to be
earthed, if the mounting brackets NXAM are used, because they ensure a
sufficient current path during fault situations.
Surge arresters
Surge arresters
Fittings for surge arresters
MWK
To protect the switch-disconnector Sectos NXA against atmospheric
overvoltages, it is often necessary to install surge arresters on one or both
sides of the switch. The new silicon rubber insulated surge arresters of ABB,
type MWK are recommended for use together with Sectos NXA.
For complete information about the surge arresters please refer to the
brochure: CH-AR 3007, published by ABB Hochspannungstechnik AG,
Switzerland.
Brackets for surge arresters
NXAM 3
The surge arresters MWK can be very conveniently installed to the same
crossarm with Sectos NXA using fittings type NXAM 3.
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Accessories
4.3 Connecting bare conductor
Sectos NXA switch-disconnector is equipped with series 400 outer-cone
bushings, on the top of which are normally installed outer insulators of
silicone rubber. This makes it possible to connect an overhead line
with bare conductors directly to the switch. Silicone rubber has excellent
electrical properties, it is hydrophobic and unbreakable. The insulator has
been tested according to IEC 1109 salt fog test with 5000 hours exposure,
which is the requirement for an insulator intended for the most severe
environments.
Terminals
Installation of
silicone rubber insulator
NXAC_
The terminals are made of copper and they are electrolytically tinned for
optimal corrosion protection. Different holes in the terminals are available
for different standards and line connectors. Please refer to the dimension
drawings at the point 5.5.
Line connectors
The conductor is fitted to the terminal with a line connector. The selection
of line connector is determined by material and size of the conductor.
Type
Line connector
OJU-ZLL 1/3
NPTL 24/3
OJU-ZLL 3/3
OJU-ZLL 4/3
KG-36/3
Conductor
material
Conductor
size/mm2
Weight
kg/pcs
Cu
Al
Al
Al
Al/Cu
16...63
62...90
2 x 16...70
2 x 50...240
50...240/10...95
0,08
0,14
0,12
0,34
0,34
Selection table for line connectors.
Bird guards
KZNC 120-160 A 01/NXA
The bare conductor connection of Sectos can be protected by means of
bird guards. When the bird guard is used, the suitable terminal and line
connector must be also selected.
Bird guards
4.4 Connecting insulated cable
A cable, terminated with series 400 Tee-connector, can be connected directly
to the outer cone bushings. Please make sure that the used type of
termination kit is suitable for outdoor use. The conventional cable terminal
can be connected to the silicone rubber insulators.
Terminating cable
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Accessories
4.5 Operating devices
Sectos NXA switch-disconnector can be operated by means of manual or
motor operating devices. The operating device is normally located near to
the ground level, and the mechanical movement is transferred to the switch
by an operating rod, which moves up and down.
Operating rods
NPTOT _
Operating rod sets are available with rods of 2 x 4 m and 3 x 3 m lengths,
each set including rod supports and necessary joint pieces.
Rod support
NPAZL 9
Protection
insulator of the
command rod
NPSZJ 30
Rod support
NPAZL 9
Extension rods
OJUP-ZY 10
The set includes one rod of 3 m, adjoint pieces and one rod support with fitting
screws. By using several extension rods and an adequate quantity of rod
supports, it is possible to install the NXA at heights of more than 20 meters.
Rod support
NPAZL 9
The operating rod is fitted to the pole with rod supports. Normally at least
2 supports are needed. The extension tube set includes 1 tube support.
Protection insulator of the operating rod
NPSZJ 30
The protection insulator is commonly used with wooden poles. Its purpose
is to increase the safety of the operator.
Command rod
NPTOT_
Manual operating device
UEKE 3
The manual operating device UEKE 3 is suitable for use with the Sectos NXA
switch-disconnector. It can be locked in open and in closed positions with
a padlock.
Manual
operating
device
UEKE 3
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Accessories
Motor operating device
UEMC 50
The motor operating device is needed, when Sectos NXA switch-disconnector
is to be remotely controlled.
The motor operating device UEMC 50 can be retrofitted in the place of manual
mechanism. The enclosure of the motor operating device is of stainless steel,
and is protected to IP 44. Three different sizes of box are available.
In the smallest one, there is room for the motor operating mechanism,
batteries and battery charger. In the larger boxes there is space reserved
for the electronic devices of the remote control system.
The recommended auxiliary voltage is 24 VDC. In the box are the push
buttons for local control and in addition every UEMC 50 has a hand crank
for emergency manual operation of the switch.
The motor operating device can be deactivated and mechanically locked
in both open and closed positions by means of a padlock. The padlock is
pushed into the hole of the hand cranking shaft disconnecting the auxiliary
circuit for both remote and local control. The padlock itself mechanically
prevents the use of the hand crank and manual operation of the switch.
Motor operating device
for outdoor installation
UEMC 50 H 1 – 24 VDC / 1
Operation time
H 1,2 s
L 3,0 s
Motor operating device
Box
1
2
3
480 x 280 x 200 mm
570 x 520 x 200 mm
570 x 620 x 300 mm
Voltage of the motor and the control
12 VDC
24 VDC
48 VDC
60 VDC
110 VDC
220 VDC
110 VAC
230 VAC
Level of accessories
1
– contctors, MCB, push buttons I and O, switch local-remote
2
– contactors, MCB, push buttons I and O
3
– contactors
4
– without contactors
1–4 – limit switch, blocking switch, heating resistor, 1 NO + 1 NC
auxiliary contact
For further information and careful selection of motor operating device,
please refer to the brochure of UEMC 50.
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Accessories
4.6 Remote control
The switch-disconnector Sectos NXA is specially designed for remote
control applications of electricity distribution networks.
Remote control requires a terminal unit and a communication between
the terminal unit and the remote control centre in addition to the motor
operating device.
DTU 1S
DTU 1
DTU 1 with "slave" stations
One practical example of a remote control terminal is the DTU, which
comprises a motor operating device with a stainless steel cabinet, where
the electronic remote control terminal is installed together with a modem
and communication equipment, which is usually radio. Additionally in the
DTU there can be different kinds of equipment for fault indication and
analysing, such as SPEF 3A2C fault indicator.
The remote control terminal DTU is suitable for use with MicroSCADA
remote control systems. Other remote control systems may require protocol
conversions, which should be checked with the supplier. The motor
operating devices UEMC 50 and the Sectos NXA switch-disconnector itself
can be used with any remote control system. The application of SPEF 2A2C
fault indicating relay together with other remote terminals might require
adaptation of the SPA-protocol.
DTU-1 type remote terminal can work as a “master station” for 7 remotely
controlled switches, in which case the 6 switches can be equipped with a
simpler DTU-1S “slave” terminals connected to the master station with
optical fibre. This arrangement permits the distance between the master
and the slave terminals up to 400 meters.
UEMC 50_
DTU 4
DTU-4 type terminal can work as a common remote terminal for 4 switches.
In this case each switch is only equipped with UEMC 50 motor operating
device. The distance between the DTU 4 and the motor operators connected
to it limited in the practice to about 20 meters, because of the voltage drop
in the motor circuits.
The communication between the DTU terminals and the remote control
center can be realised by many different means, using radios, telephone
lines, other types of cables, etc.
DTU 4 with 3 additional
motor operating devices
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Accessories
4.7 Indication of faults
Current sensors
With Sectos NXA switch-disconnector it is possible to use different kinds of
equipment for fault indication. Most of fault indicating devices are normally
connected to the remote control system, but there are also such devices,
which give fault indication locally, for instance with flashing light.
Current sensor
Connection
box including
over voltage
protection
Down-lead
cable
Motor
operating
device
Fault
indicator
Sectos NXA switch-disconnector
with fault indicators
KOKU 072 G3
The current sensor can be installed around the bushings of Sectos NXA
switch-disconnector. Because the bushing insulators form the primary insulation, the same current sensor is suitable for all line voltages. The current
sensor KOKU 072 G3 applies to the fault indicator SPEF 3A2C.
The current sensors of each phase are connected to the shielded downlead
cable KOHZ 11 in the branching box SPEC 4, which also includes an overvoltage protection. When ordering the down-lead cable, please advise the
required length. All above mentioned parts, - current sensors, branching
box, and cables, can be supplied either with screw connectors or with plugin connectors.
Fault indicator
SPEF 3A2C
The fault indicator gives indication of short-circuit, over-load, phase unbalance and earth-fault situations, and in addition it is a useful information
source for observation of the load under normal conditions. The fault indicator
is connected to the remote control terminal through digital SPA-bus.
The remote control computer can then read from the memory of the fault
indicator the magnitudes of the fault currents and the normal phase currents
at any time. Also it is possible to program to the SPEF 3A2C relay alarm limits
for over-load conditions, and to change these limits directly from the remote
control centre. The current information to the indicator comes from the
sensors KOKU 072 G3 readily at such a level that no measured value
converters are needed. The fault indicator needs an auxiliary voltage,
24 VDC, which is normally obtained from the same battery, feeding also
the motor, the remote terminal and the communication equipment. For
closer information, please refer to the technical brochure of SPEF 3A2C.
Fault indicator sensing the variations
of electric and magnetic fields
Linetroll 3000
An example of a different kind of fault indicating device is Linetroll 3000,
manufactured by Nortroll AS, which is installed to the pole below the electric
line. The device senses the intensity of electric field and variations
of magnetic field. It indicates a short-circuit or an earth-fault situation by
means of a flashing light or by a normally open contact, which can give
the alarm to the remote control system. The advantage of the Linetroll 3000
is that there is no need to connect any sensors to the medium voltage line.
For further information, please refer to the brochure of Linetroll 3000.
ABB Power Distribution
17
NXA 1 GB
Sectos NXA
Dimension drawings
5 Dimension drawings
5.1 Sectos NXA switch-disconnectors
1198
162
700
669
55
151
42
110°
462
Models for bare conductors:
682
NXA 24 C_, NXA 36 C_
NXA 27 C_, NXA 38 C_
700
669
55
151
ø14
674
126
162
42
110°
462
126
Models for cable Tee-connectors:
674
ø14
NXA 24 E_, NXA 36 E_,
NXA 27 E_, NXA 38 E_
ø 1 3
1 7 4
2 6 4
2 6
9 4
ø 9
6 7
4 7
ø 1 1
1 1 4
2 3
M 1 2
1 3
Dimensions of
earthing terminal
Dimensions of
the hanging edge
ø 2 5 m m , s p lin e d
18
NXA 1 GB
ABB Power Distribution
Sectos NXA
Dimension drawings
5.2 Manual operating device
UEKE 3
R o d ø 3 0 . . 3 4 m m
H o le ( 2 + 2 k p l)
ø 1 3 m m p a d lo c k
7 5 0
3 5 0
ø 1 3
ø 2 3
1 7 2
ø 1 3
6 5
1 2 0
5.3 Motor operating device
ø22
ø22
ø22
570
480
525
200
200
280
UEMC 50_1_
ABB Power Distribution
570
615
300
620
520
UEMC 50_2_
UEMC 50_3_
19
NXA 1 GB
Sectos NXA
Dimension drawings
5.4 Mounting brackets
80 . . 100
120 . . 160
M12
M12
120 . . 160
80 . . 100
NXAM 1
NXAM 2
Brackets for fitting the Sectos NXA_ below the crossarm.
ø13
ø13
80 . . 100
100 . . 160
M12
80 .. 100
NXAM 4
M12
100 . .160
NXAM 5
Brackets for fitting Sectos NXA_ above the crossarm.
20
NXA 1 GB
ABB Power Distribution
Sectos NXA
Dimension drawings
5.5 Terminals
ø17
150°
ø17
110
ø11
9
110
ø11
150°
ø13
30
23
ø13
5
5
26
30
40
60
Terminal for OJUP ZLL line connectors
type NXAC 1
"Australia" model
type NXAC 2
ø17
ø17
ø13
150°
ø13
150°
125
50
ø13
44,5
ø13
130
5
5
40
40
Terminal for ANSI-connectors
type NXAC 3
Terminal for IEC-connectors
type NXAC 4
ø17
46
ø14
ø14
126
44,5
80
5
Example of a terminal for
ANSI connectors, suitable for use together
with bird guards, type NXAC 5
ABB Power Distribution
21
NXA 1 GB
Sectos NXA
Dimension diagram
5.6 Clossarm
2000
900
27
25
27
27
50
25
1000
22
22
22
1900
50
80*80*4
50
Crossarm for up to 24 kV, type NPTRN1T6
1425
50
712,5
712,5
22
3*22
50
80*80*4
2750
2850
Crossarm for 36 kV, type J401464
22
NXA 1 GB
ABB Power Distribution
Sectos NXA
Connection diagrams
6
Connection diagrams
6.1 Main circuit diagram of Sectos NXA
Kaasusäiliö
Gas density
alarm contact
0
I
Position indicator
Auxiliary contacts
F
Spring mechanism
Operating shaft
6.2 Auxiliary circuit diagram of the switch equipped
with single spring type actuator
Multi-pin plug-in terminal
1
6
2
2
7
1
3
Main circuit
ABB Power Distribution
Gas density
alarm contact
3
5
8
4
4
5
8
6
9
10
7
9
Auxiliary contacts
23
NXA 1 GB
Sectos NXA
Connection diagrams
6.3 Auxiliary circuit diagram of Sectos NXA equipped with
double-spring type actuator
Multi-pin plug-in terminal
1
6
2
2
7
1
3
Main circuit Gas density
alarm contact
Tripping coil
3
5
8
4
5
4
6
8
9
10
7
9
Auxiliary contacts
6.4 Down-lead cable plug
24
NXA 1 GB
1
2
3
4
5
1
2
3
4
5
6
7
8
9
6
6
7
8
9
6
The shield of the cable is connected
to the frame of the plug.
ABB Power Distribution
Sectos NXA
Connection digrams
6.5 Connection of curent sensors to fault indicator
Current sensors (3 pcs) KOKU 072 G3
L1
L2
L3
S1
S2
S1
S2
S1
S2
B
W
B
W
B
W
X1/1
SPEC 4
X1/3
X1/5
X2/1
X4/1
X2/3
X4/2
B
X1-1
X4/3
W
X1-2
X3/1
X2/5
X3/3
X3/5
X4/4
Y
X1-3
R
B
W
Y
R
Blue
White
Yellow
Red
X1-7
Fault indicator SPEF 3A2 C
ABB Power Distribution
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NXA 1 GB
26
NXA 1 GB
ABB Power Distribution
ABB Power Distribution
27
NXA 1 GB
NXA 1 GB 97-03
28
NXA 1 GB
Waasa Graphics Oy
5000, 97-03
ABB Transmit Oy
MV Systems Division
P.O.Box 613, FIN-65101 Vaasa, Finland
Tel: +358 10 22 44000
Fax: +358 10 22 44661
ABB Power Distribution