Circuit-Breaker Failure Protection - ABB REX 521 Technical Reference Manual, Standard Configurations

REX 521
9.3.4.2.
132
Protection Relay
Technical Reference Manual, Standard Configurations
timer and the BS2 will block the trip signal. Please refer to the CD-ROM Technical
Descriptions of Functions (1MRS 750889-MCD) for more information about the
different protection function blocks.
In this application example the digital input DI9 is connected to the input signal
Blocking 1 and then routed to the BS1 input of the overcurrent stage 3I>>. The
Blocking 1 signal can be found in Main menu\Configuration\Input
Signals\Blocking 1\ where DI9 is selected. The checksum for the
switchgroup in Main menu\Configuration\Input SWGRP\
Blocking 1\ should be 2 to block the 3I>>.

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 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 two-stage earth-fault protection are selected the checksum for
CBFP will be 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.
1MRS 751802-MUM