Simulation of Two-Dimensional Streamer Discharge in Uniform Field in Low SF6 Content Mixtures

SF₆ gas is an important insulated medium and is widely used in electric power industry for gas-insulated equipment. However, the environment impact made SF₆ a greenhouse gas and be used under strict limitations. As a substitute to SF₆, SF₆/N₂ gas mixture is a promising gas insulated medium. Though the simulations of streamer discharge have been carried out in SF₆/N₂ gas mixtures by many investigators, most of the researches are based on one-dimensional simulation. Using two-dimensional model, the formation and propagation of streamers in SF₆/N₂ gas mixtures, which contains 10% SF₆, is simulated in the paper. The simulation is based on accurate numerical solution of Poisson´s equation with the continuity equations for electrons, negative and positive ions. Flux-corrected transport technique (FCT) is used for the solution of transport equation of charged particles under the action of the space-charge electric field. Photoionization in the gashas been taken into account. Streamers in the mixture have been found to be considerably different from those in SF₆. The charged particles densities and electric field, which are important to describe the development of streamers and to estimate the insulated strength of the gas mixture, are presented in this paper.