Analysis On Discharge Behaviors In Air-Gap In Rod-Plane Electrode

Currently,air is one of the main gas insulated mediums and achievements on the research of air-gap discharge mechanism under non-uniform field at atmospheric pressure have been made,but researches on air-gap discharge characteristics at low pressure and the influence of initial electrons on the air-gap discharge are less.So the researches on air-gap discharge under low pressure and different initial electrons have important significance for deeply understanding in gas discharge process.The model of rod-plate electrode with a 4mm gap is established in this dissertation and the Finite Element Method is used to solve particle continuity equations and Poisson equation in fluid model to simulate and analyze the air-gap discharge process under 1.1/2.1/4.1/8 and 1/16 atmospheric pressure.The processes such as ionization,attachment,recombination and diffusion in particles are considered in the simulation process.According to the gas discharge simulation process,the distribution regulation of space electric field intensity.effective ionization coefficient,the density of electrons,positive ions and negative ions are obtained finally.Comparing and analyzing the simulation results,the results show that air-gap discharge processes under 1.1/2,1/4.1/8 and 1/16 atmospheric pressure are similar.But as the pressure increases,the applied voltages in air-gap discharge are higher and the electrons density and electric field intensity in air-gap discharge process increases.The applied voltages includes 18kV,12kV,8kV,5.2kV and 3.2kV.Meanwhile,the influences of different density and positions of initial electrons under rod-plate electrode with a 4mm gap on the air-gap discharge process are analyzed in this dissertation.The results show that:when the density of initial electrons increases,the space electron density and electric field intensity increase a little and the discharge time which includes 12ns.12.6ns and 13ns shorten.When the position of initial electrons changes,the varying of discharge parameters are not obvious.so the influence of the position of initial electrons on air-gap discharge process can be ignored.This dissertation not only clearly describes the air-gap discharge processes under different pressures.but also analyzes the influences of the density and position of initial electrons on air-gap discharge process which can help understanding the air-gap discharge mechanism.forming the foundation for the further research of air-gap discharge under different conditions.