Description
2.10 Zone-selective interlocking ZSI
3WA1 air circuit breaker
190 Equipment Manual, 02/2023, 92310000002-06
The specified parameters can be set in the following menus of the display. The call of
parameter "ST: ZSI IN" is shown as an example.
2.10.5 Compatibility
The ZSI function of the 3WA circuit breaker is a further development of existing systems
for SENTRON circuit breakers. With appropriate settings, there is full selectivity even
when using older circuit breaker families and fuses.
Note
Backward compatibility
The ZSI function of the 3WA air circuit breakers is compatible with the ZSI function of
the 3WL air circuit breakers and the 3VA molded case circuit breakers.
The ZSI function of the 3WL and 3VA circuit breakers operates with the fixed delay
t
ZSI
50 ms for the short-time-delayed short-circuit protection ST and the fixed delay
t
ZSI
100 ms for the ground-fault protection GF. In contrast to this, the ZSI times can be
set for the 3WA circuit breaker.
When used together with the 3WL and 3VA circuit breakers in a power distribution
system, the delay times t
ZSI
must be set to 50 ms (ST) or 100 ms (GF) for each 3WA.
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