P54x/EN OP/La4 Operation
(OP) 5-142
MiCOM P543, P544, P545 & P546
OP
4.1.7.2 Auto-reclose initiation (P543/P545)
Auto-reclose is initiated from the internal protection of the relay.
By default, all “instantaneous” schemes will initiate auto-reclose, therefore current
differential, Zone 1 distance, Aided Scheme 1, and Aided Scheme 2 will all initiate AR.
For these instantaneous tripping elements, it is possible to override initiation for user set
combinations of multi-phase faults if required, by use of the ‘Multi Phase AR’ Block
setting. This will prevent auto-reclose initiation, and drive the sequence to lockout.
The directional aided schemes, the DEF schemes and TOR (distance option only) can
be selected to Initiate AR or Block AR in the auto reclose settings. The overcurrent,
earthfault, and other distance zones (where optionally specified) can be selected to
Initiate AR, Block AR or cause No Action in the auto reclose settings.
4.1.7.3 Auto-reclose inhibit following manual close (P543/P545)
The AR Inhibi
t Time setting can be used to prevent auto-reclose being initiated when the CB
is manually closed onto a fault. Auto-reclose is disabled for the AR Inhibit Time following
manual CB closure.
4.1.7.4 AR lockout (P543/P545)
If prote
ction operates during the reclaim time, following the final reclose attempt, the relay
will be driven to lockout and the auto-reclose function will be disabled until the lockout
condition is reset. This will produce an alarm, AR Lockout.
The block auto-reclose logic in the relay will also cause an auto-reclose lockout if
auto-reclose is in progress. The BAR input assigned to an opto input will block
auto-reclose and cause a lockout if auto-reclose is in progress. The auto-reclose logic can
also be set to block auto-reclose for 2 and 3 phase faults or to block auto-reclose for 3 phase
faults only using the setting Multi Phase AR - Allow AR/BAR 2&3 Phase/BAR 3 Phase in
the Auto-reclose menu. Also, the protection functions can be individually selected to block
auto-reclose using the settings, Initiate AR, No Action or Block AR in the Auto-reclose
menu.
Auto-reclose lockout can also be caused by the CB failing to close because the CB springs
are not charged/low gas pressure or there is no synchronism between the system voltages
indicated by the AR CB Unhealthy and AR No Checksync alarms.
An auto-reclose lockout is also given if the CB is open at the end of the reclaim time.
Note: Lockout, can also be caused by the CB condition monitoring functions
maintenance lockout, excessive fault frequency lockout, broken
current lockout, CB failed to trip and CB failed to close and manual
close - no check synchronism and CB unhealthy. These lockout
alarms are mapped to a composite signal “CB Lockout Alarm”.
4.1.7.5 Reset from lockout (P543/P545)
The Rese
t Lockout input assigned to an opto input can be used to reset the auto-reclose
function following lockout and reset any auto-reclose alarms, provided that the signals which
initiated the lockout have been removed. Lockout can also be reset from the clear key or the
CB CONTROL command Lockout Reset.
The Reset Lockout by setting, CB Close/ User interface in CB CONTROL is used to
enable/ disable reset of lockout automatically from a manual close after the manual close
time AR Inhibit Time.
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