2.12 Automatic Reclosure Function
137
7ST6 Manual
E50417-G1176-C251-A3
Separate binary inputs exist for switching the thermal auto reclose function on and off
and for blocking it. Likewise, there are separate indications for the status of the thermal
auto reclose function. For circuit breaker supervision, interaction with a synchro-
check, the manual-close feature and the dynamic blocking time, the parameters of the
general auto reclose function are used.
Notes on the Infor-
mation List
The most important information about automatic reclosure is briefly explained insofar
as it was not mentioned in the following lists or described in detail in the preceding text.
„>BLK 1.AR-cycle“
(FNo. 2742) and
„>AR BLK >1st“
(FNo. 13874)
The associated reclosure cycles are blocked. If the blocking state already exists when
the automatic reclosure function is initiated, the blocked cycle is not executed and may
be skipped. The same is true if the auto reclose function is started outside the blocked
cycle. If the block signal of a cycle appears while this cycle is being executed (busy)
the automatic reclosure function is blocked dynamically; no further automatic reclo-
sures cycles are then executed.
„AR EN Z1B“
(FNo. 13887),
„AR EN Z1L“
(FNo. 13888) and
„AR EN Z1“
(FNo.
13886)
If the signal
„AR EN Z1B“
is active, the automatic reclosure function is ready for the
first reclosure cycle. An active signal
„AR EN Z1L“
indicates that the auto reclose
function is ready for a second or higher cycle. On the other hand, the signal
„AR EN
Z1“
indicates that the auto reclose function is in its last cycle, or blocked. For example,
external protection functions can use these signals to release accelerated or over-
reaching trip stages prior to the corresponding reclose cycle.
„AR is NOT ready“
(FNo. 2784)
The automatic reclosure is not ready for reclosure at the moment. In addition to the
reasons mentioned above for static blocking, there are also obstructions during the
course of the reclose cycles such as "action time run out" or "last reclaim time run-
ning". This information is particularly helpful during testing because no protection test
cycle with reclosure may be initiated during this state.
„>BLOCK AR“
(FNo. 2703)
A blocking via the BI (2703:
„>BLOCK AR“
) may cause both a static and a dynamic
blocking. An activation of the BI with the auto reclose function in normal state will
cause a static blocking. The blocking is terminated immediately when the binary input
has been cleared, and the automatic reclosure function resumes its normal state.
If the auto reclose function is already running when the blocking arrives, the dynamic
blocking takes effect. In this case, the blocking time defined by the parameter
T BLK
DYN
(address
3422
) is started when the binary input is set. After the time has expired,
the function checks whether the BI is still active. If it is, the auto reclose function
passes from dynamic to static blocking. If the binary input is no longer active when the
time has expired and if no new blocking conditions apply, the automatic reclosure
system resumes normal state.
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