Characterization of Partial Discharge of Metal Particles Inside Gas-Insulated Switchgear under Excitation of Disconnecting Switch Operating Overvoltage

SF6 gas-insulated metal-enclosed switchgear, also known as combination appliances, referred to as GIS(gas insulated switch), has the advantages of small footprint, not affected by the external environment, high operational reliability, maintenance-free, and is widely used in the power system, and the failure rate of combination appliances has a direct impact on the stability of the power grid. This paper describes a 252kV can-type circuit breaker in the same interval isolation switch operation in the arc extinguishing chamber discharge fault, comprehensive recording data, disintegration analysis, through the isolation switch operation overvoltage simulation calculation, field partial discharge test comparison analysis, concluded that the cause of the failure for the dynamic and static main contact abnormal wear, generating more metal particles, in the operation of vibration (pneumatic mechanism) and closing air flow disturbance Under the vibration of operation and the disturbance of air flow, more metal particles were generated and accumulated in the tank below the shielding cover on the side of the movable contact. The high-frequency over-voltage generated during the tripping process of the isolation switch was conducted to the movable contact side of the circuit breaker, which aggravated the jumping of the metal particles accumulated at the tank, and triggered a discharge from the bottom of the shielding cover to the tank below, and provided suggestions for the subsequent reconstruction.