Effect of radial ion diffusion on simulation of positive corona discharge in SF6 gas

The effect of the drift and diffusion of electrons, positive and negative ions during corona discharge processes must be taken into account for an accurate analysis of such dynamic processes. In particular, the bi-directional drift and diffusion of all charged particles when voltages are applied for long periods of time must be carefully considered. Then we simulate the positive corona discharge of SF₆ taking account of the effect of such bi-directional drift and diffusion of charged by employing a triple channel model where the discharge space consisted of three coaxial layers. In this paper, we report on a new method for shortening computation time by setting non-uniformly spaced calculation points near and between the electrodes. Further, we discuss the effects of ion diffusion and the presence of residual space charge on the distributions of charged particle density, electric field and the waveforms of the corona pulse current