1. After the vacuum circuit breaker and grounding knife in the high and low voltage complete switch cabinet are closed in the test position, the trolley circuit breaker cannot enter the working position.Its function is to prevent the on-load switch from closing.

2. When the vacuum circuit breaker and the grounding knife of the high and low voltage complete switch cabinet are closed, the grounding knife cannot be closed.Its purpose is to prevent the ground wire from closing.

3. When the vacuum circuit breaker in the high and low voltage complete switch cabinet is closed during operation, the working position of the trolley circuit breaker cannot be exited. The back door of the screen cabinet is locked by the mechanism on the grounding knife and the cabinet door.Its function is to prevent accidentally entering the charged area.

4. When the vacuum circuit breaker in the high and low voltage complete switch cabinet is closed, the grounding knife cannot be put into operation, and the back door of the screen cabinet