Computer Simulation Of Streamer Discharge Process For Gas Insulation In Short Gap

The inert gas sulfur hexafluoride (SF6) is widely used in the electrical power industry as an insulator for gas-insulated equipment in power stations. But SF6is a greenhouse gas, which has been classified as a restricted gas since the Kyoto Protocol was signed in1997. Therefore, it is urgent to find a gas instead of SF6. The SF6/N2gas mixtures is most likely alternative for SF6. The major work of this paper is simulate the streamer discharge process of the SF6/N2gas mixtures, which is conducive to understand the mechanism of gas discharge. The research can provide necessary theory to support for the design of the electric insulation equipment.In this paper, two-dimensional fluid dynamics model is used to simulate plate-plate air gap streamer discharge. Model includes the continuity equation descripted of the convection-diffusion process of the positive and coupled Poisson equation to analysis of spatial electric field distribution. The finite element method is used to solving the model, and the Flux-Corrected Transport(FCT) is used to inhibit the Numerical concussion. The-purpose is to achieve two-dimensional dynamic simulation of the discharge process. Simulation including ionization, attachment, integration, and diffusion processes of a variety of charged particles, and consider the the impact of photoionization in the discharge process.In this paper,10%SF6-90%N2,50%SF6-50%N2and pure SF6gas streamer discharge progress under the same initial and boundary conditions were simulated, and the simulation results were compared and analyzed, the results show:SF6gas mixtures with high content is relatively less likely to be breakdown. And in the discharge process cathode-directed streamer can be observed. It shows that the photoionization can accelerated development of streamer.The simulation result can describe the streamer discharge process and different particles distribution in SF6/N2gas mixtures accurately.The densities of different particles and the electric field intensity can be calculated quantitatively.