tVN is the definite time delay for the trip function of the residual voltage protection, given
in s.
9.7 Breaker failure protection CCRBRF(50BF)
9.7.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Breaker failure protection, 3-phase
activation and output
CCRBRF
SYMBOL-U V1 EN
50BF
9.7.2 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 object. 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 object. 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 testing.
9.7.3 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.
Section 9 1MRK 506 369-UUS -
Current protection
540 Line distance protection REL670 2.2 ANSI
Application manual
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