Figure. 5.4.8 - 48. Retrip and CBFP when "Current and DO" is the selected criterion.
When the current threshold setting of
I
set
and/or
I0
set
is exceeded, the current-based protection is
activated. At the same time, the counters for RETRIP and CBFP are halted until the monitored output
contact is controlled (that is, until the primary protection operates). When the tripping signal reaches
the primary protection stage, the RETRIP and CBFP counters start calculating the set operating
time. The tripping of the primary protection stage is constantly monitored in this configuration. If the
current is not reduced below the setting limit or the primary stage tripping signal is not reset, a
RETRIP signal is sent to the redundant trip coil. If the retripping fails and the current is not reduced
below the setting limit or the primary stage tripping signal is not reset, the function also sends a CBFP
signal to the incomer breaker. If the primary protection function clears the fault, both counters
(RETRIP and CBFP) are reset as soon as the measured current is below the threshold settings or the
tripping signal is reset. This configuration allows the CBFP to be controlled with current-based
functions alone, and other function trips can be excluded from the CBFP functionality.
A
AQ
Q-M257
-M257
Instruction manual
Version: 2.07
116
© Arcteq Relays Ltd
IM00021
Summary of Contents for AQ-M257
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