Isolation Switch Operation Sequence

The correct operating sequence of the isolation switch:
(1) Firstly, when operating the isolation switch, it is necessary to check that the circuit breaker of the corresponding circuit is indeed in the open position to prevent the isolation switch from being pulled or closed under load.
(2) When the line is shut down or powered on, the isolation switches must be pulled and closed in sequence. During power outage operation, the circuit breaker must be pulled first, followed by the line side isolation switch, and then the bus side isolation switch. The power transmission operation sequence is opposite to the power outage sequence. This is because in the event of misoperation, following the above sequence can narrow the scope of the accident and avoid artificially expanding the accident to the busbar.
(3) During operation, if serious defects such as severe damage to insulators or transmission rods of isolation switches are found, the operation shall not be carried out.
(4) During the operation of the isolation switch, there should be on duty personnel on site to check the opening and closing positions, synchronization, contact depth, and other items phase by phase, to ensure that the isolation switch operates correctly and is in the correct position.
(5) The isolation switch should generally be operated in the main control room. When the remote control electrical operation fails, manual or electric operation can be carried out on-site, but it must be approved by the station master or technical leader, and can only be carried out with on-site supervision.
(6) Electrical, electromagnetic, and mechanical locking devices are installed between the isolation switch, grounding switch, and circuit breaker to prevent misoperation. When switching operations, be sure to proceed in sequence. If the locking device fails or the isolation switch and grounding switch cannot operate normally, the corresponding circuit breaker and switch position status must be strictly checked according to the locking requirements. Only after verifying that there are no errors can the locking be released for operation.