Breaker Failure Protection Ccrbrf (50Bf) - ABB RET670 Applications Manual

Section 3
IED application
Name Values (Range)
ThetaInit 0.0 - 95.0
Warning 1.0 - 500.0
tPulse 0.01 - 0.30
3.7.8
3.7.8.1
3.7.8.2
470
Unit Step
% 1.0
Min 0.1
s 0.01

Breaker failure protection CCRBRF (50BF)

Function description
Breaker failure protection
Application
In the design of the fault clearance system the N-1 criterion is often used. This means
that a fault needs to 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, 3-phase activation and output (CCRBRF, 50BF) 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).
CCRBRF (50BF) 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.
Setting guidelines
The parameters for Breaker failure protection 3-phase activation and output CCRBRF
(50BF) are set via the local HMI or PCM600.
The following settings can be done for the breaker failure protection.
Default Description
50.0 Initial Heat content, in % of heat content trip
value
30.0 Time setting, below which warning would be
set (in min)
0.10 Length of the pulse for trip signal (in msec).
IEC 61850 IEC 60617
identification identification
CCRBRF
3I>BF
SYMBOL-U V1 EN
1MRK504116-UUS C
ANSI/IEEE C37.2
device number
50BF
Application manual