Simulation of positive corona discharge in SF/sub 6/ gas by multichannel model when bidirectional diffusion of ions is considered

Abstract

Computer simulation has been widely used as a method for investigating the properties of gas discharges, where both the bidirectional drift and diffusion of all charged particles of the corona discharge under the application of voltage for long period of time have to be considered. In this paper, we simulate the positive corona of SF/sub 6/ gas in a point to plane electrode system configuration using a multichannel model considering the conditions mentioned above. In corona discharges, residual space charges formed as a result of previous discharges affect the electric field distribution, the charged particle density distribution, and the waveforms of the corona pulse current. Therefore, we compare and discuss the calculated differences by using the triple channel model, in which ion diffusion in the radial direction is considered, and using the single channel model, in which the diffusion in the direction is not considered. The differences between the waveforms of the corona pulse trains, when trigger electrons are given at intervals of a time, are also discussed. The distance that the streamer progresses is also compared. The simulation results using the multichannel model are a good approximation to the actual experimentally measured waveform of corona pulse current.