1.Circuit-Breaker Failure Protection; 2.Trip-Circuit Supervision - ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS 751802-MUM
11.1.5.2.
11.1.5.3.
Protection Relay
Technical Reference Manual, Standard Configurations
Circuit-breaker failure protection
All of the current-based protection functions in the standard configuration H01
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. The CBFP signal is
then connected to any of the output relays via
Main menu\Configuration\Output Signals\, and in this example the
circuit-breaker failure signal is connected to the power output 1, PO1.
Trip-circuit supervision
The trip-circuit supervision is available for the HSPO1 relay. If the resistance of the
trip circuit exceeds a certain limit, for instance due to a bad contact or oxidation, the
supervision function will be activated and a trip-circuit supervision alarm signal will
be provided after an adjustable delay time. The settings for the function can be found
in Main menu\Cond. monit.\TCS\.
To avoid unnecessary alarms, trip-circuit supervision can be blocked by
the BS signal, which disables the supervision output when the circuit breaker is
open. The BS signal is configured to be operated by the "CB pos. open" status from
the selected digital input. The BS signal can be connected via the switchgroup in
Main menu\Input SWGRP\TCS\. The default setting of the parameter is "Not
in use".
Another solution is to use an external resistor to prevent the TCS alarm. Please refer
to Technical Reference Manual, General (1MRS 751108-MUM) for more
information about the trip-circuit supervision.
REX 521
171