The correct operating sequence of isolation switches

(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 switch must be pulled and closed in sequence. When operating a power outage, 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 case 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, the on duty personnel should inspect the opening and closing positions, synchronization conditions, contact depth, and other items on site phase by phase to ensure the correct operation and position of the isolation switch.
(5) Isolation switches 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 the permission of the station master or technical director must be obtained, and it can only be carried out under 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, they must be carried out in sequence. If the locking device fails or the isolation switch and grounding knife switch cannot operate normally, the corresponding circuit breaker and knife 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.