Siemens 3VA1 100 A Manual page 82

Description
2.6 Protection system
Operating principle
The diagram below demonstrates the operating principle of zone-selective interlocking:
- - -
A
E
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.
82
Communication cable
Output, transmits the blocking signal
Input, receives the blocking signal
t "Virtual" tripping time of I protection
i
t Delay time setting of S protection
SD
t Delay time of all molded case circuit breakers
ZSI
which detect the short circuit but do not receive
a blocking signal when ZSI is activated
3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02