The concept of five prevention:
1. Anti-load opening and closing disconnector;
2. Prevent false opening and closing of circuit breaker;
3. Anti-load closing grounding switch;
4. Load transmission when the anti-grounding switch is closed;
5. Prevent entering the live space by mistake.
The five-prevention lock is the lock set installed to achieve the above five-prevention measures. To achieve the specific function of five-prevention, it also needs to cooperate with the microcomputer five-prevention system or through strict personnel five-prevention operation rules.
“Five electrical precautions” of high-voltage switchgear:
“Interlocking” of high-voltage switchgear is an important measure to ensure the safe operation of power grid, ensure the safety of equipment and personnel, and prevent misoperation. GB3906-1991 “3~35 kV AC Metal-enclosed Switchgear” has made clear provisions for this. Generally, “interlocking” is described as: preventing false opening and closing of circuit breaker; preventing opening and closing of disconnector with load; preventing hanging (closing) of grounding wire (grounding switch) with power; preventing closing of grounding wire (switch) with power; preventing entering into live space by mistake. The above five contents to prevent electrical misoperation are referred to as “five preventions”. “five preventions” Devices are generally divided into mechanical, electrical and comprehensive categories. At present, there are many types of high-voltage switchgear on the market, most of which have shaft perfect interlocking mode.
1. After the vacuum circuit breaker trolley in the high-voltage switch cabinet is closed at the test position, the trolley circuit breaker cannot enter the working position. (Prevent closing with load).
2. When the grounding switch in the high-voltage switch cabinet is closed, the trolley circuit breaker cannot be closed. (Prevent closing with grounding wire).
3. When the vacuum circuit breaker in the high-voltage switchgear is closed, the rear door of the panel and cabinet is locked with the cabinet door by the mechanism on the grounding knife. (Prevent entering the live space by mistake).
4. The vacuum circuit breaker in the high-voltage switch cabinet is closed during operation, and the closing grounding switch cannot be put into operation. (Prevent live hanging of grounding wire).
5. The vacuum circuit breaker in the high-voltage switch cabinet cannot exit from the working position of the trolley circuit breaker when it is closed.
Post time: Jan-11-2023