ABB REQ650 Applications Manual page 113

1MRK 505 383-UEN A
Breaker protection REQ650 2.2 IEC
Application manual
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 any check of breaker
position.
Table 13: 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 applications 1 out of 3 is sufficient. For Contact operation means
back-up trip is done when circuit breaker is closed (breaker position is used).
IP>: Current level for detection of breaker failure, set in % of IBase. This
parameter should be set so that faults with small fault current can be detected. The
setting can be chosen in accordance with the most sensitive protection function to
start the breaker failure protection. Typical setting is 10% of IBase.
I>BlkCont: If any contact based detection of breaker failure is used, this function
can be blocked if any phase current is larger than this setting level. If the
FunctionMode
N/A
Current
Contact
Current/Contact
Current
Contact
Current/Contact
Section 6
Current protection
Description
the re-trip function is not
activated
re-trip is done if the phase
current is larger than the
operate level after re-trip time
has elapsed
re-trip is done when auxiliary
contact position indicates that
breaker is still closed after re-
trip time has elapsed
both methods according to
above are used but taken into
I>BlkCont
account also
re-trip is done without check of
current level
re-trip is done without check of
auxiliary contact position
re-trip is done without check of
current level or auxiliary contact
position
107