Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546
(OP) 5-181
OP
Leader CB Leader AR mode Follower CB Follower AR Mode
CB1 1Ph CB2 1Ph or 3Ph
CB1 3Ph CB2 3Ph
CB1 1/3Ph CB2 1/3Ph or 3Ph
CB1 1Ph, 3P or 1/3Ph No follower AR No follower AR
CB2 1Ph CB1 1Ph or 3Ph
CB2 3Ph CB1 3Ph
CB2 1/3Ph CB1 1/3Ph or 3Ph
CB2 1Ph, 3P or 1/3Ph No follower AR No follower AR
If 1Ph or 1/3Ph follower auto-reclose mode is selected, the follower can perform single
phase auto-reclose only if the leader circuit breaker has performed single phase auto-
reclose. If the leader has tripped and reclosed three phase, the follower is also forced to trip
three phase, and will then reclose three phase provided three phase auto-reclose is
permitted for the follower circuit breaker. If the follower circuit breaker trips three phase, and
three phase auto-reclose is not permitted for the follower, then the follower circuit breaker
will lock out without reclosing.
Single phase reclosing is permitted only for the first shot of an auto-reclose cycle. If two or
more shots are enabled, then in a multi-shot auto-reclose cycle the second and subsequent
trips and reclosures will be three phase.
The scheme can be configured to control a single circuit breaker installation. If the menu
setting Num CBs is set to CB1 Only, all menu settings and indications relating to CB2 are
redundant and hidden, and the scheme controls only CB1. If the menu setting Num CBs is
set to CB2 Only, all menu settings and indications relating to CB1 are redundant and
hidden, and the scheme controls only CB2. In these single circuit-breaker configurations,
the selected circuit-breaker auto-reclose can be selected to 1Ph, 3Ph or 1/3Ph AR mode
indicating single phase, three phase, or single/three phase operation.
5.6.1 Time delayed and high speed auto-reclosing (P544/P546)
The auto
-reclose function offers multi-shot auto-reclose control, selectable to perform up to a
four shot cycle. Dead times
(Note 1)
for all shots
(Note 2)
are independently adjustable. Should a
circuit breaker close successfully at the end of the dead time, a Reclaim Time starts. If the
circuit breaker does not trip again, the auto-reclose function resets at the end of the reclaim
time. If the protection trips again during the reclaim time the relay advances to the next shot
in the programmed cycle, or, if all programmed reclose attempts have been made, the auto-
reclose goes to lockout.
Note 1: Dead Time denotes the open (dead) interval delay of the CB
Note 2: A Shot is a reclosure attempt
5.6.2 Auto-reclose logic inputs (P544/P546)
The auto
-reclose function uses inputs in the logic, which can be assigned and activated from
any of the opto-isolated inputs on the relay via the programmable scheme logic (PSL).
Contacts from external equipment may be used to influence the auto-recloser via the optos,
noting that the circuit breaker status (open/closed) must also be available via auxiliary
contact inputs to the relay.
These logic inputs can also be assigned and activated from other sources. The function of
these inputs is described below, identified by their DDB signal text. The inputs can be
selected to accept either a normally open or a normally closed contact, programmable via
the PSL editor.
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