Breaker Failure Protection Ccrbrf(50Bf) - ABB REC670 Applications Manual

Section 8
Current protection
8.9
8.9.1
8.9.2
206
ThetaInit: Heat content before activation of the function. This setting can be set a little
below the alarm level. If the transformer is loaded before the activation of the
protection function, its temperature can be higher than the ambient temperature. The
start point given in the setting will prevent risk of no trip at overtemperature during the
first moments after activation. ThetaInit: is set in % of the trip heat content level.
Warning: If the calculated time to trip factor is below the setting Warning a warning
signal is activated. The setting is given in minutes.

Breaker failure protection CCRBRF(50BF)

Identification
Function description
Breaker failure protection, 3-phase
activation and output
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.
IEC 61850 IEC 60617
identification identification
CCRBRF
3I>BF
SYMBOL-U V1 EN-US
1MRK 511 401-UUS A
IP14514-1 v6
M14878-1 v5
ANSI/IEEE C37.2
device number
50BF
M13916-3 v7
Bay control REC670 2.2 ANSI
Application manual