Circuit Breakers Without Zsi Function - Siemens SENTRON VL Series System Manual

5.2.2.7

Circuit breakers without ZSI function

Circuit breakers without ZSI function can be integrated into a system equipped with ZSI.
However, they must have no delay time since otherwise the selectivity of the circuit breakers
cannot be guaranteed.
Short-circuit at circuit breaker
● t
Short-circuit at circuit breaker
delay time t
no ZSI-IN signal is detected, switch-off is executed with a delay time t
t
100 ms ① > 50 ms ②
⇒ circuit breaker ② trips before circuit breaker ①.
The short-circuit is switched off non-selectively.
● t
Short-circuit at circuit breaker
delay time t
②
50 ms.
t
50 ms ② > 0 ms ①
⇒ circuit breaker ① trips before circuit breaker ②.
The short-circuit is switched off selectively.
3WL/3VL circuit breakers with communication capability - PROFIBUS
System Manual, 03/2011, A5E01051353-02
①
= 100 ms
sd
of 100 ms. The short-circuit is also detected by circuit breaker
sd
> t
sd ZSI
= 0 ms
sd
of 0 ms (instantaneous). The short-circuit is also detected by circuit breaker
sd
and since no ZSI-IN signal is detected, switch-off is executed with a delay time t
> t
ZSI sd
① ①
. Circuit breaker will switch off the short-circuit with a
① ①
. Circuit breaker will switch off the short-circuit with a
Zone Selective Interlocking
5.2 Examples
②
and since
of 50 ms.
ZSI
ZSI
of
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