Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546
(OP) 5-193
OP
5.6.6.6.2 Auto-reclose initiation by external protection equipment (P544/P546)
The following DDB signals are available for mapping in the PSL from opto inputs or
communication inputs to initiate auto-reclosing.
DDB (535): CB1 Ext Trip A
DDB (536): CB1 Ext Trip B
DDB (537): CB1 Ext Trip C
DDB (534): CB1 Ext Trip 3Ph
DDB (539): CB2 Ext Trip A
DDB (540): CB2 Ext Trip B
DDB (541): CB2 Ext Trip C
DDB (538): CB2 Ext Trip 3Ph
If mapped, activation of the input to the DDB will initiate auto-reclose.
5.6.6.6.3 Auto-reclose initiation and cycle by trip test (P544/P546)
A user
command (Test Autoreclose under COMMISSION TESTS) in the P544/P546 menu
can be used to initiate an auto-reclose cycle. Four separate commands can be executed,
each command comprising a 100 ms pulse output when the relevant “execute” option is
selected. Available commands are: Trip Pole A / Trip Pole B / Trip Pole C2 / Trip 3 Pole.
There is also a No Operation option to exit the command field without initiating a test.
5.6.6.7 Sequence counter (P544/P546)
The sequ
ence counter logic is shown in AR Figure 18 (logic diagram supplement).
The auto
-reclose logic includes a counter known as the sequence counter. Unless auto-
reclose is in progress, the sequence counter will have a value of 0. Following a trip, and
subsequent auto-reclose initiation, the sequence counter is incremented. The counter
provides output signals indicating how many initiation events have occurred in any auto-
reclose cycle. These signals are available as user indications and are used in the logic to
select the appropriate dead timers or, for a persistent fault, force a lockout.
The logic generates the following sequence counter outputs which are used in the auto-
reclose shots counter logic (refer section 5.6.6.14).
DDB 84
7: Seq. Counter = 1 is set when the counter is at 1;
DDB 848: Seq. Counter = 2 is set when the counter is at 2;
DDB 849: Seq. Counter = 3 is set when the counter is at 3; and
DDB 850: Seq. Counter = 4 is set when the counter is at 4.
Every time the relay trips the sequence counter is incremented by 1. The auto-reclose logic
compares the sequence counter values to the number of auto-reclose shots setting, AR
Shots. If the counter value exceeds the setting then the auto-reclose is locked out.
In the case of a successful auto-reclose cycle the sequence counter resets to zero.
5.6.6.8 Auto-reclose cycle selection (P544/P546)
The auto
-reclose cycle selection determines, for a dual breaker configuration, the logic to
determine which of the circuit breakers will act as leader/follower and whether the reclosing
will be single phase or three phase. The logic is shown in AR Figure 19 and Figure 21 (logic
diag
ram supplement).
In a dual circuit breaker arrangement, when an auto-reclose cycle is started, single phase or
three phase reclosing is asserted for each circuit breaker, according to whether the circuit
breaker has tripped single phase or three phase, and according to whether single phase
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