Earth-Fault Stage Io>>> To Trip The Breaker On The Hv Side Of The Transformer; Circuit-Breaker Failure Protection; Disturbance Recorder - ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS 751802-MUM
9.2.4.3.
9.2.4.4.
9.2.4.5.
Protection Relay
Technical Reference Manual, Standard Configurations
overcurrent start signal from the 3I>> stage is routed via Start 1 and then connected
to the signal output 2, SO2. The checksum in this application example for Start 1 is
2.
Earth-fault stage Io>>> to trip the breaker on the HV side of the
transformer
The trip signal from the earth-fault instantaneous stage can be routed to an output
relay to trip the breaker on the HV side of the transformer. To use the trip signal from
the earth-fault function, the signal has to be routed via
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 trip signal of the earth-fault stage Io>>> is routed via
Trip 2 and then connected to the power output 2, PO2. The checksum in this
application example for Trip 2 is 32.

Circuit-breaker failure protection

All of the protection functions in the standard configuration B01 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.
The settings for the breaker failure are set separately for each protection function.
For example, to set the CBFP time for 3I>>, go to
Main menu\Protection\3I>>\Control setting, where it is possible
to set the "CBFP time" from 100 ms to 1000 ms. The control parameter "Trip pulse"
sets the width of the trip output signal, but also of the CBFP output signal.
The CBFP signals from the protection functions are routed to the output signals via
the output switchgroups. These settings can be found in
Main menu\Configuration\Output SWGRP\CBFP. When the three-stage
overcurrent and the two-stage earth-fault protection are selected the checksum for
CBFP is 31.
The CBFP signal is then connected to any of the output relays, via
Main menu\Configuration\Output Signals\. In this example, the
circuit-breaker failure signal is connected to the power output 1, PO1.

Disturbance recorder

The disturbance recorder (DREC) can be found in
Main menu\Measurement\DREC\. All of the measured current signals as well
as all of the start signals from the protection functions are connected to the DREC
in the B01 standard configuration.
The recording can be triggered by any of the alternatives listed below:
• triggering on the rising or falling edge of the protective start signals
• triggering on current measurement
• manual triggering via the HMI or with the external input signal
• triggering via communication parameter
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