Application Guide - NP900 Series
112 (504
)
A996A
the monitored output contact is controlled (primary protection operates). From the tripping
signal of the primary protection stage the counters for retrip and CBFP start to calculate
the set operating time. The tripping of the primary protection stage is constantly monitored
in this configuration and if the current is not decreased under the setting limit and the trip
signal from primary stage is not reset 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 or
the trip signal is reset. This configuration allows the CBFP to be controlled on current
based functions only and other function trips can be excluded from the CBFP functionality.
Figure 3.2.9.4-52 Retrip and CBFP when selected criteria is current or DO.
In case when the current based protection activates so that either Iset and/or I0Sset
current threshold setting is exceeding the counters for retrip and CBFP start to calculate
the set operating time. From the tripping signal of the primary protection stage the
counters for retrip and CBFP start to calculate the set operating time. The tripping of the
primary protection stage is constantly monitored in this configuration regardless of the
current status. The pick-up of CBFP is active until current is not decreased under the
setting limit or the trip signal from primary stage is not reset. In case if either of these
conditions are met until the timers set time first is issued retrip and if either of the
conditions is active 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 and the trip signal is reset. This configuration allows the CBFP to be controlled on
Содержание NP900 Series
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Страница 49: ...Application Guide NP900 Series 49 504 A996A Figure 3 2 1 3 25 Definite time operating characteristics...
Страница 50: ...Application Guide NP900 Series 50 504 A996A Figure 3 2 1 3 26 IEC predefined characteristics NI VI LTI and EI...
Страница 52: ...Application Guide NP900 Series 52 504 A996A Figure 3 2 1 3 28 IEEE predefined characteristics EI MI and VI...
Страница 243: ...Application Guide NP900 Series 243 504 A996A Figure 3 3 2 1 122 NPS biased thermal trip curves with kNPS values 7 and 10...
Страница 491: ...Application Guide NP900 Series 491 504 A996A 3 7 5 6 SETTING EXAMPLE...
Страница 504: ...Application Guide NP900 Series 504 504 A996A A996A...