Study on fluid model of disconnector arc applied in very fast transient overvoltage

The essence of the mathematical model of disconnectors' multiple reignition arc is the repeated breakdowns of SF6. In this study, the kinetic properties of microparticles are studies based on the streamer discharge theory, and a fluid arc mathematical model applied in centimetre clearance is established. Ultra-High Voltage (UHV) disconnector manufactured by Pingao Electric Co. Ltd of Henan Province is selected as the object and the resistance change process of contact clearance multiple reignition arc is simulated by finite difference method-finite element method-flux corrected transport self-programming in MATLAB based on the chamber structure and operating characteristics. UHV gas-insulated switchgear very fast transient overvoltage (VFTO) test platform is built to gain the characteristics of VFTO waveforms generated by the disconnector's operation. Compared with simulation results, the test data shows that the fluid arc mathematical model can scientifically explain the dynamic development process of microparticles in the contact clearance and the calculation results are consistent with the test data. In addition, the arc fluid mathematical model combines the structure and operating characteristics of the switch with the development process of microparticles, which can better guide the design of the switch, and provide a theoretical basis for the suppression of VFTO with the disconnector itself.