4.Trip Signal From Second Residual Voltage Stage; 5.Second Settings For Residual Voltage Protection; 6.Circuit-Breaker Failure Protection - ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS 751802-MUM
10.2.5.4.
10.2.5.5.
10.2.5.6.
Protection Relay
Technical Reference Manual, Standard Configurations
As mentioned above, the start signal from the first high-set overcurrent stage 3I>>
can be routed to the first high-set stage 3I>> of the HV relay. To use the start signal
from a protection function the signal has to be routed via
Main menu\Configuration\Output SWGRP\Start 1 or \Start 2.
When the start signal has been routed, the output relay has to be selected in
Main menu\Configuration\Output Signals. In this example, the
overcurrent start signal from the 3I>> stage is routed via Start 1 and then connected
to the signal output 1, SO1. The checksum in this application example for Start 1 is
2.
Trip signal from second residual voltage stage
The trip signal from the residual voltage high stage can be routed to an output relay
to provide a back-up trip signal to the outgoing feeders of the network.
To use the trip signal from the residual protection function, the signal has to be
routed via the Main menu\Configuration\Output SWGRP\Trip 2 or
\Trip 3. When the trip signal has been routed, the output relay has to be selected
in Main menu\Configuration\Output Signals.
In this example, the directional earth-fault stage Io>>-> is configured as a Uo>>
protection and is routed via Trip 2 and then connected to the power output 2, PO2.
The checksum in this application example for Trip 2 is16.
Note also that the events (e.g. start and trip) for the residual overvoltage protection
will be sent from the directional earth-fault stages.
Second settings for residual voltage protection
If an external control signal determined from the earthing situation of the network is
available, it can be used for changing to the second settings of the residual voltage
protection. The usage of different settings can be useful when switching between a
compensated network and an isolated network which results in changes in the level
of the neutral voltage during earth-fault.
In this example, the digital input DI5 is connected to the input signal Group and then
routed to the group input of the directional earth-fault functions, which in this
example is configured as residual protection. The Group signal can be found in
Main menu\Configuration\Input Signals\GROUP\ where DI5 is
selected. The checksum for the switchgroup in
Main menu\Configuration\Input SWGRP\GROUP\ should be 2 to
change to the second settings for earth-fault. In the control settings for the
directional earth-fault functions, the group input has to be chosen for the group
selection. Please refer to the CD-ROM Technical Descriptions of Functions (1MRS
750889-MCD) for more information about the directional earth-fault function.
Circuit-breaker failure protection
All of the protection functions in the standard configuration M01 provide a delayed
trip signal CBFP after the trip signal unless the fault has not disappeared during the
set CBFP time delay. In the circuit-breaker failure protection, the CBFP output can
be used for operating an upstream circuit breaker.
REX 521
155