ABB Relion 670 Series Applications Manual page 190

Section 7
Current protection
Document
revision
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7.6.2 Identification
Function description
Breaker failure protection, 3-phase
activation and output
7.6.3 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 CCRBRF (50BF)will issue a backup 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 either by means of current measurement or as detection
of closed status using auxiliary contact.
CCRBRF (50BF) can also give a retrip command. This means that a second trip signal is sent to the
protected object circuit breaker. The retrip function can be used to increase the probability of operation of
the breaker, or it can be used to avoid backup trip of many breakers in case of mistakes during relay
maintenance and testing.
7.6.4 Setting guidelines
The parameters for Breaker failure protection 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 and
SBase. Note that this function will only use IBase value.
Operation: Disabled/Enabled to enable/disable the complete function.
FunctionMode: It defines the way the detection of failure of the breaker is performed. In the Current
mode, the current measurement is used for the detection. In the CB Pos mode, the CB auxiliary contact
status is used as an indicator of the failure of the breaker. The mode Current or CB Pos means that both
ways of detections can be activated. The CB Pos mode is used in applications where the fault current
through the circuit breaker is small. This can be the case for some generator protection application (for
example, reverse power protection) or in the case of line ends with weak end infeed.
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Product History
revision
2.2.4 -
2.2.4 -
2.2.5 -
IEC 61850
identification
CCRBRF
© 2017 - 2021 Hitachi Power Grids. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
50BF
3I>BF
SYMBOL-U V1 EN-US
1MRK 505 370-UUS Rev. K
M14878-1 v5
M13916-3 v8
M11546-4 v11
Busbar protection REB670
Application manual