Alstom MiCOM P54 Series - 4. SINGLE CIRCUIT BREAKER CONTROL: P543;P545 OPERATIONAL DESCRIPTION; 4.1 Single and three phase auto-reclosing; 4.1.1 Time delayed and high speed auto-reclosing; 4.1.2 Auto-reclose logic inputs (P543;P545)

P54x/EN OP/La4 Operation
(OP) 5-136 MiCOM P543, P544, P545 & P546
OP
4. SINGLE CIRCUIT BREAKER CONTROL : P543/P545 OPERATIONAL
DESCRIPTION
This section describes the P543/P545 operational control of a single circuit breaker.
The circuit breaker control and monitoring in the P543/P545 provides single phase or three
phase switching of a feeder controlled by a single circuit breaker
4.1 Single and three phase auto-reclosing
4.1.1 Time delayed and high speed auto-reclosing
The Mi
COM P543/P545 will initiate auto-reclosure following any current differential, Zone 1,
or distance-aided scheme trips which occur. In addition, the user can selectively decide to
auto-reclose for trips from time-delayed distance zones, overcurrent and earth (ground)
elements, and DEF aided schemes.
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
the CB 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, goes to lockout.
Note 1: - Dead Time denotes the open (dead) interval delay of the CB.
Note 2: - A Shot is a reclosure attempt
Logic diagrams to explain the operation of the auto-reclose feature are grouped together at
the end of this section.
4.1.2 Auto-reclose logic inputs (P543/P545)
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 CB 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.
4.1.2.1 CB healthy (P543/P545)
The majo
rity of circuit breakers are only capable of providing one trip-close-trip cycle.
Following this, it is necessary to re-establish sufficient energy in the circuit breaker before
the CB can be reclosed. The CB Healthy input is used to ensure that there is sufficient
energy available to close and trip the CB before initiating a CB close command. If on
completion of the dead time, sufficient energy is not detected by the relay from the CB
Healthy input for a period given by the CB Healthy time timer, lockout will result and the CB
will remain open.
4.1.2.2 BAR (P543/P545)
The BA
R input will block auto-reclose and cause a lockout if auto-reclose is in progress. It
can be used when protection operation without auto-reclose is required.
4.1.2.3 Reset lockout (P543/P545)
The Re
set Lockout 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.