As you know there are six areas of vulnerability regarding the dependable tripping of a circuit breaker as illustrated below.

–          the dc supply

–          the tripping contact

–          wiring runs

–          the circuit breaker auxiliary contact

–          the trip coil

–          the circuit breaker mechanism

The most comprehensive monitoring and supervision system encountered for local trip command is shown in below Figure .  This monitors the tripping circuit whether the circuit breaker is closed or open and will only give an output if the tripping circuit or the trip coil becomes open circuited or the dc supply fails. Relay A must operate at full voltage; relay B must pick up in series with relay A.

As you can see any cutting or loss connection of inter-trip circuit couldn’t monitored by this circuit.

 

 

How can us monitor and supervise any inter-trip wire that considered for tripping of local circuit breaker due to any remote wired inter-trip command?

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[محمد سعید جعفرپورKeymaster]

This modification can be a good solution.

[Author]

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