Simulation Research Of Streamer Discharge Under Low Atmospheric Pressure

As the coverage area of high voltage equipment becomes wider and wider,high-voltage insulation technique for some region with relatively extremeclimates, such as low air pressure, becomes the focus of the research. Becauseair is the most commonly used insulation filling medium, studies of airdischarge at low-pressure environment are very significant for the rationaldesign of the structure and parameters of high-voltage insulation equipment.Based on the theory of air discharge at low pressure, an investigation of theexperiment result of domestic and foreign about the effect of pressure on thestreamer discharge is conducted. In this paper, it makes some theoreticalanalysis of the influence of pressure on the parameters during the streamerdischarge. A simulation of streamer discharge which considers pressure as theimpact factor is established and ultimately obtains some charts of particleconcentration and space electric field distribution under different pressures atvarious times during the streamer propagation. The results provide somereference value to the Insulation design of high-voltage equipment under low pressure.The main work is as follows:(1) Plenty of scientific papers about the effects of pressure on the streamerdischarge from domestic and foreign are investigated.(2) The mechanism of gas discharge breakdown is introduced and differentdischarge theories are compared in this paper. The influence exerted by pressureon the behavior of charged particles in the electric field and the value of theparameters, such as the impact ionization coefficient and the recombinationcoefficient, under streamer discharge mode is analyzed. And all these impactsare described through hydromechanics particle transport equations.(3) Aiming at solving the multi-field coupling particle transport equation ofthis paper, several numerical calculation methods are studied and finally finiteelement method combined with the Galerkin approximation method is adopted.Through this method，the equation will be derived into weak form, with takingthe Poisson equation as an example for the transformation. In the software it issolved in weak form with the partial differential equations (PDE) module.(4) A streamer discharge module with10mm long air gap between rod andplane electrode is established which is simulated in the finite element softwareand obtains some charts of electron density, positive-ion density, negative-iondensity and space electric field distribution under different pressures at varioustime. Finally, a detailed theoretical analysis of the result is made.