Reasons for circuit breaker misoperation

If the circuit breaker is automatically closed without operation, it is a false switch. The main reasons for misclosing are:

(1) The DC system is grounded at two points to make the closing control loop connected.

(2) The control circuit is closed due to the accidental closing of the autorecloser relay contacts, and the circuit breaker is closed.

(3) Misoperation of the operating mechanism, etc., for example, the spring-loaded spring lock of the spring operating mechanism is unreliable. When a vibration occurs, the lock may be automatically released, causing the circuit breaker to close itself.

After checking that there is no closing operation, the circuit breaker is misclosed, and the misaligned circuit breaker should be opened. If the circuit breaker is again misaligned after pulling open, the closing fuse should be removed to check the electrical and mechanical aspects. The reason for reporting dispatch and superior authorities is to disable and overhaul the circuit breaker.