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6LE007331A
Fault example b):
-
In the event of a fault downstream of circuit breaker Q2,
only circuit breakers Q1 and
Q2 detect the fault. Thanks to the connection cable between the circuit breakers, circuit
breaker Q2 informs circuit breaker Q1 that it has detected the fault. Circuit breaker Q1 then
maintains its time delays whilst circuit breaker Q2 inhibits its time delays to eliminate the
fault instantly.
Adjusting the ZSI protection setting
To take into account zone selectivity, the ZSI protection must be activated on the
hw+ circuit breakers using the
Hager Power Setup
commissioning and test software.
ZSI protection settings
Short time delay protection ZSI
ON-OFF (OFF by default)
Ground fault protection ZSI
ON-OFF (OFF by default)
N.B.
It is important to ensure that ZSI protection on a hw+ circuit breaker is kept deactivated
when not using the zone selective function. In this case, setting the ZSI protection to ON will
systematically reduce the trigger time to an almost instantaneous time ranging from between
20 and 100 ms.
Connection of ZSI protection
hw+ air circuit breakers have 6 ZSI terminal blocks enabling the upstream or downstream
circuit breakers to be connected to deploy zone selective interlocking (ZSI).
Type of connection
Total number of circuit
breakers
Max. distance between 2 circuit
breakers
Upstream
3
300 m
Downstream
7
300 m
Recommended connection cable: 1 to 1.5 mm
2
shielded twisted pair.
The types of protection device
3.7 Zone Selective Interlocking function (ZSI)
