Zone-Selective Interlocking Zsi; Advantage; Structure And Principle Of Operation Of The Zsi System - Siemens SENTRON 3WA1 Manual

2.10

Zone-selective interlocking ZSI

2.10.1

Advantage

Note
Zone selective interlocking ZSI can be used for the 3WA air circuit breakers from the ID
No. OE/230101500000 in connection with the ZSI200 module.
ZSI will presumably be available for the 3WA air circuit breaker as of 01/2023 (circuit
breaker) or 03/2023 (ZSI module).
The load on a power distribution system can be reduced under short-circuit and ground
fault conditions when circuit breakers are used in a ZSI system.
Short circuits and ground faults are disconnected after a short delay, independently of
the coordination of the response characteristics of the circuit breakers.
This zone selective interlocking feature allows full selectivity without time grading to be
achieved with a low break time, thereby increasing the supply reliability of non-faulty
outgoing feeders.
Definition of "total selectivity" from IEC 60947-2
Overcurrent selectivity where, in the presence of two overcurrent protective devices in
series, the protective device on the load side effects the protection without causing the
other protective device to operate.
2.10.2

Structure and principle of operation of the ZSI system

The ZSI system can be set up with 3WA air circuit breakers with ETU600 electronic trip
unit and the ZSI200 module. The ZSI200 module is connected to the ETU600 electronic
trip unit of the circuit breaker via the CubicleBUS².
The ZSI interfaces port A and port B of the ZSI200 modules are connected via a two-wire
line.
3WA1 air circuit breaker
Equipment Manual, 02/2023, 92310000002-06
2.10 Zone-selective interlocking ZSI
Description
187