Application Guide - NP900 Series
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A996A
Figure 3.2.9.4-50 Retrip and CBFP when selected criteria is current only.
In case when the current based protection activates so that either Iset and/or I0Sset
current threshold setting is exceeded the counters for retrip and CBFP start to calculate
the set operating time. The tripping of the primary protection stage is not monitored in this
configuration and if the current is not decreased under the setting limit first is issued retrip
and if the current is not decreased in time also CBFP will be issued to upstream breaker.
If the primary protection function clears the fault e.g. the circuit breaker operates normally
the counters for retrip and CBFP are reset immediately the current is measured below the
threshold settings.
Figure 3.2.9.4-51 Retrip and CBFP when selected criteria is current and DO.
In case when the current based protection activates so that either Iset and/or I0Sset
current threshold setting are exceeded the counters for retrip and CBFP are halted until
