Siemens SENTRON - Zone Selective Interlocking and Time Selectivity

Methods of implementing selectivity using circuit breakers
3.5 Zone selective interlocking
Selectivity for 3VA molded case circuit breakers
Configuration Manual, 08/2016, A5E03603181010-01
33
3.5.1 Zone selective interlocking and time selectivity
If a circuit breaker detects a fault in a combined ZSI/time selectivity system, the following
applies:
● A "block" signal is present:
The original delay time t
sd
remains valid.
● A "block" signal is not present:
The original delay time t
sd
is replaced by a delay time t
ZSI
(defined non-operation time).