The correct operation sequence of the isolation switch

Update date:2018-03-26 Source:MAXGE

(1) When the isolation switch is first operated, the circuit breaker of the corresponding circuit should be checked to be in the disconnected position first to prevent the pull-out and closing of the disconnector with the load.


(2) When the line is stopped or transmitted, the disconnector must be pulled and closed in order. When a power failure occurs, the circuit breaker must be pulled first, then the line side disconnector must be pulled, and then the busbar side disconnector should be pulled. The power transmission operation sequence is the reverse of the power failure sequence. This is because when the misoperation occurs, the accident range can be reduced in the above order, so as to avoid artificially expanding the accident to the bus.


(3) In operation, if serious damage of the insulator, serious damage of the switch rod, etc. is found, no operation is allowed.

(4) When the disconnector is operated, on-site personnel should be checked phase by phase to check their points, closing position, condition during the same period, contact depth and other items, to ensure that the isolation switch action is correct and the position is correct.

(5) Disconnectors should generally be operated in the main control room. When the remote control electrical operation fails, manual or electric operation can be performed on-site at the site. However, permission from the station manager or technical person in charge must be obtained and the site supervision can be conducted.


(6) Electrical, electromagnetic and mechanical locking devices are installed between the disconnector, grounding switch and circuit breaker to prevent erroneous operation. When switching, it must be performed in order. If the locking device malfunctions or the isolation switch and grounding switch cannot be operated normally, the corresponding circuit breaker and switch position must be checked strictly according to the requirements of the latching. Only after the check is correct can the latch be released to operate.

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