P54x/EN OP/La4 Operation
(OP) 5-200
MiCOM P543, P544, P545 & P546
OP
Circuit breaker failure to close. If the circuit breaker fails to close because, for example,
the circuit breaker springs are not charged, the gas pressure is low, or there is no
synchronism between the system voltages indicated by the AR CBx Unhealthy and
AR CBx No Checksync alarms, auto-reclose will be blocked and forced to lockout.
Circuit breaker open at the end of the reclaim time. An auto-reclose lockout is forced if
the circuit breaker is open at the end of the reclaim time.
Circuit breaker fails to close when the close command is issued.
Block follower if leader fails to close is set. If the setting BF if Lfail Cls in the
AUTORECLOSE column of the menu is set to Enable, the active follower circuit breaker
will lockout if the leader circuit breaker fails to reclose.
Circuit breaker fails to trip correctly.
Three phase dead time started by line dead violation. If the line does not go dead within
the Dead Line Time time setting when the dead time start is determined by the menu
setting 3PDTStart WhenLD, the logic will force the auto-reclose sequence to lockout
after expiry of the setting time.
Single phase evolving to multi phase fault. If, after expiry of the discriminating time from
the Protection Re-operation + Evolving fault logic (refer section 5.6.6.8), a single
pha
se fault evolves into a two, or three phase fault, the internal signal Evolve Lock will
be asserted that will force the auto-reclose to lockout.
Leader/Follower invalid selection via opto. If the Leader/Follower AR mode in the
AUTORECLOSE menu is set to be selected via the opto-inputs, Opto, then if the logic
detects an invalid auto-reclose mode combination selection, it will force both CB1 & CB2
to lockout if a trip occurs.
If CB1 or CB2 is locked out, the logic generates the alarms CBx AR Lockout (DDB 306
/328) for the corresponding circuit breaker. In this condition, auto-reclose of the circuit
breaker cannot be initiated until the corresponding lockout has been reset. The methods of
resetting from the lockout state are discussed in the next section.
Circuit breaker lockout, can also be caused by the circuit breaker condition monitoring
functions:-
Maintenance lockout,
Excessive fault frequency lockout,
Broken current lockout,
Circuit breaker failed to trip,
Circuit breaker failed to close,
Manual close failure - no check synchronism / circuit breaker unhealthy situation.
These lockout alarms are mapped to a signals CBx mon LO Alarm (DDBs 300 & 322 for
CB1 and CB2 respectively) and CBx LO Alarm. (DDBs 860 & 1599 for CB1 and CB2
respectively).
5.6.6.18 Reset circuit breaker lockout (P544/P54
6)
The lockout conditions caused by the circuit breaker condition monitoring functions (including
manual close failure) described in section 5.6.6.17 can be reset according to the condition of
the Rst CB m
on LO by setting found in the CB CONTROL column of the menu.
The Rst CB mon LO by setting has two options CB Close, and User interface.
If Rst CB mon LO By is set to CB Close then closure of the circuit breaker will be a trigger
for lockout reset. If set to CB Close, a further setting, CB mon LO RstDly, becomes visible.
This is a timer setting that is applied between the circuit breaker reclosing, and the lockout
being reset.
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