2 Functions
246
7SA522 Manual
C53000-G1176-C155-3
If, on the other hand, the internal automatic reclosure function is to be used, the type
of reclosure must be selected during the configuration of the functions (see Section
2.1.1.2) in address $XWR5HFORVH the AR control mode and in address the
$5FRQWUROPRGH.
Up to 8 reclosure attempts are allowed with the integrated automatic reclosure func-
tion in the 7SA522. Whereas the settings in the addresses to are common
to all reclosure cycles, the individual settings of the cycles are made from address
onwards. It is therefore possible to set different individual parameters for the first
four reclose cycles. From the fifth cycle onwards the parameters for the fourth cycle
apply.
The automatic reclosing function can be turned 21 or 2)) under address $872
5(&/26(.
A prerequisite for automatic reclosure taking place after a trip due to a short-circuit is
that the circuit-breaker is ready for at least one TRIP–CLOSE–TRIP–cycle at the time
the automatic reclosure circuit is started (i.e. at the time of the first trip command). The
readiness of the circuit-breaker is signalled to the device through the binary input
´!&%5HDG\µ (F.No 371). If no such signal is available, leave the setting under
address &%"75,3 = 12 because no automatic reclosure would be possible
at all otherwise. If circuit breaker interrogation is possible, set &%"75,3 = <(6.
Furthermore the circuit-breaker ready state can also be interrogated prior to every re-
closure. This is set when setting the individual reclose cycles (see below).
To check the ready status of the circuit breaker is regained during the dead times, you
can set a circuit breaker ready monitor time under address &%7,0(287. The
time is set slightly longer than the recovery time of the circuit breaker after a TRIP–
CLOSE–TRIP–cycle. If the circuit-breaker is not ready again by the time this timer ex-
pires, no reclosure takes place, the automatic reclosure function is blocked dynami-
cally.
Waiting for the circuit-breaker to be ready can lead to an increase of the dead times.
Interrogation of a sync. check (if used) can also delay reclosure. To avoid uncontrolled
prolongation it is possible to set a maximum prolongation of the dead time in this case
under address 7'($'(;7. This prolongation is unlimited if the setting ∞ is
applied. This setting is only possible via DIGSI
®
at Additional Settings. Remember
that longer dead times are only permissible after three-pole tripping when no stability
problems arise or when a sync. check takes place before reclosure.
The blocking time 75(&/$,0 (address ) defines the time that must elapse, after
a successful
reclosing attempt, before the automatic reclosing function is reset. Re-
tripping of a protection 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.
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 if there is no possibility to monitor the circuit
breaker (see above) during multiple reclosing (e.g. because of auxiliary contacts
missing and information on the circuit breaker ready status). Then the reclaim time
must be longer than the recovery time of the circuit-breaker.
The blocking duration following Manual–Close–detection 7%/2&.0& (address
) must guarantee the circuit breaker to open and close reliably (0.5 s to 1 s). If a
fault is detected by a protection function within this time after closing of the circuit
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