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2 Functions
160
7ST6 Manual
E50417-G1176-C251-A3
Figure 2-44
Logic of the Start and End Criterion
As soon as the start criterion has been fulfilled, the parameterised operating time on
tripping is started. The time of commencement of separation of the circuit breaker con-
tacts is thus determined. The end of the trip procedure, including arc deletion is deter-
mined via another given parameter (CB tripping time) supplied by the manufacturer of
the circuit breaker.
In order to prevent an incorrect calculation procedure in case of circuit breaker failure,
the current criterion
BkrClosed I MIN
(address
251
) verifies whether the current
was actually switched off after expiry of the CB tripping time. When the logic release
is fulfilled by the current criterion, the calculation and evaluation methods are initiated.
After these have been completed, the end criterion of the 2P-procedure of the circuit
breaker maintenance is fulfilled and ready for a new initiation.
It should be noted that the 2P-procedure is blocked in case of parameterisation errors.
This state is signalled via the indications
„2P T sett.fail“
(FNo. 16020),
„2P
blk n PaErr“
(FNo. 16028) or
„2P blk I PaErr“
(FNo. 16027).
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