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reclosure cycles, the individual settings of the cycles are made from address 3450 on-
wards. It is possible to set different individual parameters for the first four reclose
cycles. From the fifth cycle on the parameters for the fourth cycle apply.
The automatic reclosing function can be turned ON or OFF under address 3401 AUTO
RECLOSE.
A prerequisite for automatic reclosure taking place after a trip due to a short-circuit is
that the circuit breaker is ready for at least one OPEN-CLOSE-OPEN cycle at the time
the automatic reclosure circuit is started, i.e. at the time of the first trip command. The
readiness of the circuit breaker is signalled to the device via the binary input „>CB1
Ready" (No. 371). If no such signal is available, leave the setting under address 3402
CB? 1.TRIP = NO because no automatic reclosure would be possible at all otherwise.
If circuit breaker interrogation is possible, you should set CB? 1.TRIP = YES.
Furthermore, the circuit breaker ready state can also be interrogated prior to every re-
closure. This is set when setting the individual reclose cycles (see below).
To check that the ready status of the circuit breaker is regained during the dead times,
you can set a circuit breaker ready monitor time under address 3409 CB TIME OUT.
The time is set slightly longer than the recovery time of the circuit breaker after a TRIP-
CLOSE-TRIP cycle. If the circuit breaker is not ready again by the time this timer ex-
pires, no reclosure takes place, the automatic reclosure function is blocked dynami-
cally.
Waiting for the circuit breaker to be ready can lead to an increase of the dead times.
To avoid uncontrolled prolongation, it is possible to set a maximum prolongation of the
dead time in this case in address 3411 T-DEAD EXT.. This prolongation is unlimited
if the setting ∞ is applied. This parameter can only be altered with DIGSI under Addi-
tional Settings. Remember that longer dead times are only permissible after three-
pole tripping when no stability problems occur.
The reclaim time T-RECLAIM (address 3403) defines the time that must elapse, after
a successful reclosing attempt, before the auto reclose function is reset. Re-tripping
by a protective function within this time initiates the next reclose cycle in the event of
multiple reclosure; if no further reclosure is permitted, the last reclosure is treated as
unsuccessful. The reclaim time must therefore be longer than the longest response
time of a protective function which can start the automatic reclosure circuit. When op-
erating the AR in ADT mode, it is possible to deactivate the reclaim time by setting it
to 0 s.
A few seconds are generally sufficient. In areas with frequent thunderstorms or
storms, a shorter blocking time may be necessary to avoid feeder lockout due to se-
quential lightning strikes or cable flashovers.
A longer reclaim time should be chosen where circuit breaker supervision is not pos-
sible (see above) during multiple reclosures, e.g. because of missing auxiliary con-
tacts and information on the circuit breaker ready status. In this case, the reclaim time
should be longer than the time required for the circuit breaker mechanism to be ready.
The blocking duration following manual-close detection T-BLOCK MC (address 3404)
must ensure the circuit breaker to open and close reliably (0.5 s to 1 s). If a fault is de-
tected by a protective function within this time after closing of the circuit breaker was
detected, no reclosure takes place and a final three-pole trip command is issued. If this
is not desired, address 3404 is set to 0.
The options for handling evolving faults are described in Section 2.10 under margin
heading „Handling Evolving Faults". The treatment of sequential faults is not neces-
sary on line ends where the adaptive dead time is applied (address 133 Auto
Reclose = ADT). The addresses 3406 and 3407 are then of no consequence and
therefore not accessible.
7SD610 Manual
C53000-G1176-C145-4
2.10 Automatic Reclosure Function (optional)
139
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