The grounding switch in high-voltage switchgear is a mechanical grounding device used for safety maintenance. During electrical equipment maintenance, it grounds potentially energized circuit breakers or busbars to prevent induced voltage from harming maintenance personnel. The typical operation procedure involves first confirming the circuit breaker is de-energized, then moving the trolley to the test position, and finally closing the grounding switch and opening the switchboard door to allow maintenance personnel to proceed.
Personal Safety Protection:
The core function of the grounding switch is to ensure grounding when maintenance personnel enter the high-voltage switchgear to prevent electric shock accidents caused by induced voltage or leakage.
Residual Charge Elimination:
For de-energized lines or equipment, the grounding switch conducts any residual charge to the ground, eliminating potential hazards.
Operation of the grounding knife switch of the high-voltage switch cabinet:
1. Power supply operation procedure in the high-voltage switch cabinet:
(1) Close all rear doors and rear covers and lock them.
(2) Insert the grounding switch operating handle into the hexagonal hole on the lower right side of the middle door and rotate it counterclockwise to put the grounding switch in the open position. The interlocking plate at the operating hole will automatically rebound to cover the operating hole and the lower door of the cabinet will be locked.
(3) Push down the transfer cart to position it, push the trolley into the cabinet to position it in the blocking position, manually push up the secondary plug, and close the trolley room door.
(4) Insert the circuit breaker trolley handle into the handle socket and rotate the handle clockwise for about 20 turns. Remove the handle when the handle is obviously blocked and accompanied by a “click” sound. At this time, the trolley is in the operating position, the secondary plug is cut off, the main circuit of the circuit breaker trolley is connected, and check the relevant signals.
(5) Operate the switch on the instrument panel to close the circuit breaker and supply power. At the same time, the green light on the instrument panel turns off and the red light turns on, indicating a successful closing.
2. Power outage operation procedure in high-voltage switchgear:
(1) Operate the switch on the instrument panel to close the circuit breaker and place it in the opening position. At the same time, the green light on the instrument panel turns on and the red light turns off, indicating a successful opening.
(2) Insert the crank handle of the circuit breaker trolley into the crank handle socket and rotate the handle counterclockwise for about 20 turns. When the crank handle is significantly blocked and accompanied by a “click” sound, remove the crank handle. At this time, the trolley is in the test position and the secondary plug is exempted. Open the trolley door and manually disconnect the secondary plug.
(3) Push the transfer trolley and lock it. Hold the trolley lock handle with both hands, unlock it with force towards the center and pull it outward. Move the trolley to the transfer trolley and lock it. Remove the transfer trolley.
(4) Check the live display. If it is not live, continue to operate.
(5) Insert the operating handle of the grounding switch into the hexagonal hole on the lower right side of the middle door and rotate it clockwise to put the grounding switch in the closed position. After confirming that the grounding switch is indeed closed, open the lower door of the cabinet and the maintenance personnel can enter for maintenance and repair.
Post time: Sep-15-2025
