Description
2.6 Protection system
3VA molded case circuit breakers with IEC certificate
Manual, 03/2019, A5E03603177010-03
83
The diagram below illustrates the operating principle of zone selective interlocking:
- - - Communication cable t
i
"Virtual" tripping time of I protection
A Output, transmits the blocking signal t
SD
Delay time setting of S protection
E Input, receives the blocking signal t
ZSI
Delay time of all molded case circuit breakers
which detect the short circuit but do not receive
a blocking signal when ZSI is activated
The ZSI function acts on the S and G ranges of the tripping characteristic. Currents within
the I range (instantaneous short circuit) continue to cause instantaneous tripping.
To Next Page
Loading...
