Process of Discharge Initiation and Arc Development on an Ice-Covered Insulator

The mechanisms of discharge initiation and arc development on an ice-covered insulator surface were studied. Investigations on discharge inception were carried out using a simplified physical model consisting of a rod-plane gap half submerged in ice. Elements derived from an analysis of inception parameters are used to develop an empirical model accounting for corona streamer propagation velocity and inception voltage/field on an ice surface. Furthermore, the corresponding physical propagation processes of a developing arc are analyzed using the mathematical model taking the arc re-ignition condition into account. Assuming arc behavior to be equivalent to time dependant impedance, it was possible to determine various arc macroscopic measurable quantities, such as leakage current and flashover voltage. The results indicate the feasibility of flashover prediction, using the proposed model