Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546
(OP) 5-139
OP
4.1.5.3 AR lockout (self reset) (P543/P545)
The AR Lockout alarm indicates that the relay is in a lockout state and that further reclose
attempts will not be made; see section 4.1.7.4 ‘AR Lockout’ for more details. This alarm can
be re
set using one of the reset lockout methods; see section 4.1.7.5 ’Reset from lockout’.
4.1.6 Auto-reclose logic operating sequence (P543/P545)
An auto-recl
ose cycle can be internally initiated by operation of a protection element,
provided the circuit breaker is closed until the instant of protection operation. The user can,
via a setting, determine if the auto-reclose shall be initiated on the rising edge of the
protection trip (Protection Op) or on the falling edge (Protection Reset).
If single pole auto-reclose [A/R Status 1P] only is enabled then if the first fault is a single
phase fault the single pole dead time (1 Pole Dead Time) and single pole auto-reclose in
progress [AR 1pole in prog] starts on the rising or falling edge (according to the setting) of
the single phase trip. If the relay has been set to allow more than one single pole reclose
[Single Pole Shot >1] then any subsequent single phase faults will be converted to 3 pole
trips. The three pole dead times ("Dead Time 2, Dead Time 3, Dead Time 4") [Dead Time 2,
3, 4] and three pole auto-reclose in progress [AR 3pole in prog] will start on the rising or
falling edge (according to the setting) of the three pole trip for the 2nd, 3rd and 4th trips
[shots]. For a multi-phase fault the relay will lockout on the rising or falling edge (according
to the setting) of the three phase trip.
If three pole auto-reclose [A/R Status 3P] only is enabled then for any fault the three pole
dead time ("Dead Time 1, Dead Time 2, Dead Time 3, Dead Time 4") [Dead Time 1, 2, 3, 4]
and three pole auto-reclose in progress [AR 3pole in prog] starts on the rising or falling edge
(according to the setting) of the three phase trip. The logic forces a 3 pole trip [Force 3 pole
AR] for any single phase fault if three pole auto-reclose [A/R Status 3P] only is enabled.
If single [A/R Status 1P] and three phase auto-reclose [A/R Status 3P] are enabled then if
the first fault is a single phase fault the single pole dead time ("1 Pole Dead Time") [1 Pole
Dead Time] and single pole auto-reclose in progress [AR 1pole in prog] starts on the rising or
falling edge (according to the setting) of the single phase trip. If the first fault is a multi-
phase fault the three pole dead time ("Dead Time 1") and three pole auto-reclose in progress
[AR 3pole in prog] starts on the rising or falling edge (according to the setting) of the three
phase trip. If the relay has been set to allow more than one reclose [Three Pole Shot >1]
then any subsequent faults will be converted to 3 pole trips [Force 3 pole AR]. The three pole
dead times ("Dead Time 2, Dead Time 3, Dead Time 4") [Dead Time 2, 3, 4] and three pole
auto-reclose in progress [AR 3pole in prog] will start on the rising or falling edge (according
to the setting) of the three pole trip for the 2nd, 3rd and 4th trips [shots]. If a single phase
fault evolves to a multi-phase fault during the single pole dead time [1 Pole Dead Time] then
single pole auto-reclose in progress [AR 1pole in prog] is stopped and the three pole dead
time [Dead Time 1] and three pole auto-reclose in progress [AR 3pole in prog] is started.
At the end of the relevant dead time, the auto-reclose single phase or three phase in
progress signal is reset and a CB close signal is given, provided system conditions are
suitable. The system conditions to be met for closing are that the system voltages are in
synchronism or dead line/live bus or live line/dead bus conditions exist, indicated by the
internal check synchronizing element and that the circuit breaker closing spring, or other
energy source, is fully charged indicated from the CB Healthy input. The CB close signal is
cut-off when the circuit breaker closes. For single pole auto-reclose no voltage or
synchronism check is required as synchronizing power is flowing in the two healthy phases.
Check synchronizing for the first three phase cycle is controlled by a setting.
When the CB has closed the reclaim time (“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 operates during the reclaim time the relay either advances to the next shot in the
programmed auto-reclose cycle, or, if all programmed reclose attempts have been made,
goes to lockout.
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