Judgment and treatment of circuit breaker “false closing”

If the circuit breaker closes automatically without operation, it is a “false closing” fault. Generally, it should be judged as follows. After inspection, it is confirmed that the operation is not closed. If the handle is in the “back” position and the red light flashes continuously, it indicates that the circuit breaker has been closed, but it is “wrong closing”. In this case, open the circuit breaker.

For the “wrong” circuit breaker, if the circuit breaker is opened and then “wrong”, it should be taken off the closing fuse, check the electrical and mechanical reasons respectively, and contact the dispatching to stop the circuit breaker and turn to maintenance. The causes of “mismatches” may include:

1. Two positive and negative points in the DC circuit are grounded to make the closing control circuit connected.

2, automatic reclosing relay a component fault connected control loop (such as internal time relay normally open contact mistakenly closed), so that the circuit breaker closed.

3, the closing contactor coil resistance is too small, and the starting voltage is low, when the DC system pulse occurs instantly, it will cause the circuit breaker to close by mistake.

The situation of “refusal to close” occurs basically in the process of closing operation and reclosing. For example, if the circuit breaker of the standby power supply refuses to close, the accident will be aggravated. It can be divided into three steps to determine the cause and treatment of circuit breaker “rejection”.

1) Check whether the previous refusal to close is caused by improper operation (such as the control switch letting go too fast), and use the control switch to merge again.

2) If the closing is still not successful, check all parts of the electrical circuit to determine whether there is a fault in the electrical circuit. Check items are: closing control power supply is normal; Whether the closing control circuit fuse and the closing circuit fuse are in good condition; Whether the contact of closing contactor is normal; Switch the control switch to the position of “closing” to see whether the closing iron core action is normal.

3) If the electrical circuit is normal and the circuit breaker still cannot be closed, it indicates that there is a mechanical fault. The circuit breaker should be stopped and reported to the scheduling arrangement for maintenance and treatment.