ABB RET670 Applications Manual page 477

1MRK504116-UUS C
Application manual
Operation: Disabled/Enabled
IBase: Base current in primary A. This current is used as reference for current setting.
It can be suitable to set this parameter to the rated primary current of the current
transformer where the current measurement is made.
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 Contact the long duration of
breaker position signal is used as indicator of failure of the breaker. The mode
Current&Contact means that both ways of detections are activated. Contact mode can
be usable 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 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. CB Pos Check (circuit breaker position check)
and Current means that a phase current must be larger than the operate level to allow re-
trip. CB Pos Check (circuit breaker position check) and Contact means re-trip is done
when circuit breaker is closed (breaker position is used). No CBPos Check means re-
trip is done without check of breaker position.
Table 105: Dependencies between parameters RetripMode and FunctionMode
RetripMode
Retrip Off
CB Pos Check
No CBPos Check
BuTripMode: Back-up trip mode is given to state sufficient current criteria to detect
failure to break. For Current operation 2 out of 4 means that at least two currents, of
the three-phase currents and the residual current, shall be high to indicate breaker
failure. 1 out of 3 means that at least one current of the three-phase currents shall be
high to indicate breaker failure. 1 out of 4 means that at least one current of the three-
phase currents or the residual current shall be high to indicate breaker failure. In most
FunctionMode
N/A
Current
Contact
Current&Contact
Current
Contact
Current&Contact
Section 3
IED application
Description
the re-trip function is not activated
a phase current must be larger
than the operate level to allow re-
trip
re-trip is done when breaker
position indicates that breaker is
still closed after re-trip time has
elapsed
both methods are used
re-trip is done without check of
breaker position
re-trip is done without check of
breaker position
both methods are used
471