ABB REX 521, Technical Reference Manual, Standard Configurations

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1MRS751802-MUM Protection Relay
Technical Reference Manual, Standard Configurations
REX 521
An operational characteristic example on overvoltage and undervoltage protection
is presented in the picture below (Fig. 11.5.3.-1).
Fig. 11.8.3.-1 Example on overvoltage and undervoltage protection
11.8.4. Connections
All the necessary settings for the connections and signal routings can be set via the
Relay Setting Tool or the local HMI.
11.8.4.1. Protection signal routing
The trip signal (Trip 1) of the protection functions is routed to the high speed power
output HSPO1 (x4.2.1/2/3/4) as well as the control-open signal for the circuit
breaker. The trip signals from the protection functions are routed to the output relay
via the output switchgroups. These settings can be found in
Main menu\Configuration\Output SWGRP\
.
As the HSPO1 is always named as the “Trip 1" output signal, the settings are made
directly in
Main menu\Configuration\Output SWGRP\Trip 1
, where
the checksum of the settings is displayed (255 by default).
Using the HMI:
To change the settings for Trip 1 go to
Output SWGRP\Trip 1
and press the
[E]-button. The different protection functions are displayed one at a time. By
pressing the [
→
] or [
←
] navigation push button, it is possible to scroll between the
different protections. By pressing the [
↑
] or [
↓
] navigation push button, the specific
protection function trip signal can be connected or disconnected. When the three-
stage overcurrent (3I> 3I>> and 3I>>>), two-stage earth fault (I
0
> and I
0
>>), two-
stage overvoltage (U> and U>>) and two-stage undervoltage (U< and U<<)
protection is selected the checksum for Trip 1 is 991. When the earth fault Io>>>
protection stage is selected the checksum for Trip 2 is 32.
70 80 90 100 110 120 130
U/Un(%)
t(s)
1
10
100
85%
70%
60 s
3 s
60 s
0.1 s
115%
130%
DT operation
IDMT operation
U> = 1.15 x Un, t> = 60 s, DT
or U> = 1.09 x Un, k = 0.2, p = 2, IDMT
U>> = 1.3 x Un, t> = 0.1 s, DT
U< = 0.85 x Un, t> = 60 s, DT
U<< = 0.7 x Un, t> = 3 s, DT
UNDERVOLTAGE
OVERVOLTAGE
OV&U
V