ABB RELION 670 Series Applications Manual page 187

1MRK 505 337-UUS A
there is a possibility to reduce the back-up trip delay for multi-phase faults. Typical setting is 90 –
150 ms.
t3 : Additional time delay to t2 for a second back-up trip TRBU2. In some applications there might
be a requirement to have separated back-up trip functions, tripping different back-up circuit
breakers.
tCBAlarm : Time delay for alarm in case of indication of faulty circuit breaker. There is a binary
input 52FAIL from the circuit breaker. This signal is activated when internal supervision in the
circuit breaker detect that the circuit breaker is unable to clear fault. This could be the case when
gas pressure is low in a SF6 circuit breaker, of others. After the set time an alarm is given, so that
actions can be done to repair the circuit breaker. The time delay for back-up trip is bypassed when
the 52FAIL is active. Typical setting is 2.0 seconds.
tPulse : Trip pulse duration. This setting must be larger than the critical impulse time of circuit
breakers to be tripped from the breaker failure protection. Typical setting is 200 ms.
7.7 Breaker failure protection, single phase version CCSRBRF
(50BF)
7.7.1 Identification
Function description
Breaker failure protection, single
phase version
7.7.2 Application
In the design of the fault clearance system the N-1 criterion is often used. This means that a fault
shall be cleared even if any component in the fault clearance system is faulty. One necessary
component in the fault clearance system is the circuit breaker. It is from practical and economical
reason not feasible to duplicate the circuit breaker for the protected component. Instead a
breaker failure protection is used.
Breaker failure protection, single phase version (CCSRBRF,50BF) function will issue a back-up trip
command to adjacent circuit breakers in case of failure to trip of the "normal" circuit breaker for
the protected component. The detection of failure to break the current through the breaker is
made by means of current measurement or as detection of remaining trip signal (unconditional).
CCSRBRF (50BF) function can also give a re-trip. This means that a second trip signal is sent to the
protected circuit breaker. The re-trip function can be used to increase the probability of operation
of the breaker, or it can be used to avoid back-up trip of many breakers in case of mistakes during
relay maintenance and test.
Application manual
IEC 61850 IEC 60617
identification identification
CCSRBRF
I>BF
SYMBOL-II V1 EN-US
Current protection
ANSI/IEEE C37.2
device number
50BF
Section 7
SEMOD127864-1 v2
SEMOD127866-2 v2
SEMOD127974-4 v2
181