ABB Relion REC670 Applications Manual page 154

Section 7
Current protection
means that a phase current must be larger than the operate level to allow re-trip.
(circuit breaker position check) and
closed (breaker position is used).
breaker position.
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.
that at least one current of the three-phase currents shall be high to indicate breaker failure.
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
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
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
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
IN> : Residual current level for detection of breaker failure set in % of IBase . In high impedance
earthed systems the residual current at phase- to-earth faults are normally much smaller than
the short circuit currents. In order to detect breaker failure at single-phase-earth faults in
these systems it is necessary to measure the residual current separately. Also in effectively
earthed systems the setting of the earth-fault current protection can be chosen to relatively
low current level. The
accordance to the setting of the sensitive earth-fault protection. The setting can be given
within the range 2 – 200 % of
t1 : Time delay of the re-trip. The setting can be given within the range 0 – 60s in steps of 0.001
s. Typical setting is 0 – 50ms.
148
No CBPos Check means re-trip is done without check of
FunctionMode
N/A
Current
Contact
Current&Contact
Current
Contact
Current&Contact
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 .
BuTripMode is set 1 out of 4 . The current setting should be chosen in
IBase .
Contact means re-trip is done when circuit breaker is
1MRK 511 358-UEN A
CB Pos Check
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
1 out of 3 is sufficient. For
FunctionMode is set
IBase .
Application manual
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