Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546
(OP) 5-137
OP
4.1.2.4 Pole discrepancy (P543/P545)
Circuit breakers with independent mechanisms for each pole normally incorporate a ‘phases
not together’ or ‘pole discrepancy’ protection device which automatically trips all three
phases if they are not all in the same position i.e. all open or all closed.
During single pole auto-reclosing a pole discrepancy condition is deliberately introduced and
the pole discrepancy device must not operate for this condition. This may be achieved by
using a delayed action pole discrepancy device with a delay longer than the single pole auto-
reclose dead time, ‘1 Pole Dead Time’. Alternatively, a signal can be given from the relay
during the single pole auto-reclose dead time, AR 1 Pole In Progress, to inhibit the pole
discrepancy device.
The Pole Discrepancy input is activated by a signal from an external device indicating that
all three poles of the CB are not in the same position. The Pole Discrepancy input forces a
3 pole trip which will cancel any single pole auto-reclose in progress and start three pole
auto-reclose in progress.
4.1.2.5 Enable 1 pole AR (P543/P545)
The En
1 Pole Reclose input is used to select the single phase auto-reclose operating
mode.
4.1.2.6 Enable 3 pole AR(P543/P545)
The En 3 Pole Reclos
e input is used to select the three phase auto-reclose operating mode.
4.1.2.7 External trip (P543/P545)
The Ex
ternal Trip 3Ph input and the External Trip A, External Trip B and External Trip C
inputs can be used to initiate three or single phase auto-reclose.
Note: These signals are not used to trip the CB but do initiate auto-reclose.
To trip the CB directly they could be assigned to the trip contacts of
the relay in the PSL.
4.1.3 Internal signals (P543/P545)
4.1.3.1 Trip initiate signals (P543/P545)
The Trip Inputs A, Trip I
nputs B and Trip Inputs C signals are used to initiate signals or
three phase auto-reclose.
Note: For single phase auto-reclose these signals must be mapped in the
PSL as shown in the default.
4.1.3.2 Circuit breaker status (P543/P545)
The CB
Open 3 ph, CB Open A ph, CB Open B ph and CB Open C ph, signals are used
to indicate if a CB is open three or single phase. These are driven from the internal pole
dead logic and the CB auxiliary inputs.
The CB Closed 3 ph, CB Closed A ph, CB Closed B ph and CB Closed C ph, signals are
used to indicate if a CB is closed three or single phase. These are driven from the internal
pole dead logic and the CB auxiliary inputs.
4.1.3.3 Check synch ok and system check ok (P543/P545)
Internal
signals generated from the internal system check function and external system
check equipment are used by the internal auto-reclose logic to permit auto-reclosure.
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