ABB RELION 670 Series Applications Manual page 184

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Section 7
Current protection
7.6.1
Identification
Function description
Breaker failure protection, 3-phase
activation and output
7.6.2
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 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.
7.6.3
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.
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
SBase ).
and (
Operation : Disabled / Enabled
FunctionMode This parameter can be set Current or Contact . This states the way the detection of
failure of the breaker is performed. In the mode current the current measurement is used for the
detection. In the mode
failure of the breaker. The mode
activated.
breaker is small. This can be the case for some generator protection application (for example
reverse power protection) or in case of line ends with weak end infeed.
RetripMode : This setting states how the re-trip function shall operate. Retrip Off means that the
re-trip function is not activated.
that a phase current must be larger than the operate level to allow re-trip.
178
Contact the long duration of breaker position signal is used as indicator of
Current&Contact means that both ways of detections are
Contact mode can be usable in applications where the fault current through the circuit
CB Pos Check (circuit breaker position check) and Current means
IEC 61850
IEC 60617
identification
identification
CCRBRF
3I>BF
SYMBOL-U V1 EN-US
1MRK 505 337-UUS A
ANSI/IEEE C37.2
device number
50BF
CB Pos Check (circuit
Application manual
M14878-1 v5
M13916-3 v6
M11546-4 v8.1.1

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