What precautions should be taken during the operation of high-voltage circuit breakers, isolating switches, load switches, and fuses?

(1) The rated breaking current of the Circuit Breaker must be greater than the maximum short-circuit current on the line.

(2) Isolation switch

1) It is strictly prohibited to connect or disconnect load current and short-circuit current. Operations can only be carried out when the line has been disconnected, so that there is a clear disconnection point between the power supply or line and the equipment.

2) Allow the isolation switch to cut off or disconnect small no-load currents.

3) When operating the isolation switch, it is necessary to follow the operating procedures. When disconnecting, first disconnect the circuit breaker, and then disconnect the isolation switch; When closing, first close the isolation switch, and then close the circuit breaker. Simultaneously ensured by mechanical or electrical interlocking devices.

(3) Load switches can only connect or cut off load currents, but cannot cut off short-circuit currents. Therefore, they are often used in conjunction with fuses.

4) Drop out fuses are only suitable for outdoor places without conductive dust and corrosive gases, flammable and explosive hazards, and severe vibrations. They can be used as short-circuit protection for 6-35kV lines or transformers with small capacity, and can connect or disconnect their no-load current or small load current. The operation of drop out fuses must be carried out according to the prescribed procedures.

The contact between the upper and lower ends of the tube fuse and the clamp must be tight and reliable, without loosening due to vibration, and without deformation or blackening due to heating when the current is high.