ABB Relion 670 Series Applications Manual page 176

Section 7
Current protection
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.
breaker position check) and
position is used).
Table 20: 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
currents and the residual current, shall be high to indicate breaker failure.
least one current of the three-phase currents shall be high to indicate breaker failure.
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
back-up trip is done when circuit breaker is closed (breaker position is used).
Pickup_PH : 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
Pickup_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
Current&Contact breaker failure for high current faults are safely detected by the current
measurement function. To increase security the contact based function should be disabled for
high currents. The setting can be given within the range 5 – 200% of
Pickup_N : Residual current level for detection of breaker failure set in % of IBase . In high
impedance grounded systems the residual current at phase- to-ground faults are normally much
smaller than the short circuit currents. In order to detect breaker failure at single-phase-ground
170
Contact mode can be usable in applications where the fault current through the circuit
CB Pos Check (circuit breaker position check) and Current means
Contact means re-trip is done when circuit breaker is closed (breaker
No CBPos Check means re-trip is done without check of breaker position.
FunctionMode
Current operation 2 out of 4 means that at least two currents, of the three-phase
IBase . Set the parameter IP> lower than the parameter I>BlkCont .
N/A
Current
Contact
Current&Contact
Current
Contact
Current&Contact
1 out of 3 is sufficient. For Contact operation means
1MRK 511 358-UUS A
CB Pos Check (circuit
Description
the re-trip function is not activated
re-trip is done if 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 account
also I>BlkCont
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
1 out of 3 means that at
1 out of 4
FunctionMode is set
IBase .
Application manual