Study of Insulator Flashovers caused by Atmospheric Ice Accumulation

This paper summarizes the results of research recently carried out on the inception and propagation of electrical discharge on an ice surface. Investigations on discharge inception were performed using a simplified physical model consisting of a rod-plane gap half submerged in ice. Empirical models are proposed, based on elements derived from the inception parameter analysis, to account for corona streamer propagation velocity and inception voltage/field on an ice surface. Furthermore, a dynamic model is proposed to predict flashover of ice-covered insulators. Assuming arc behavior to be a time dependant impedance, it was possible to determine various arc characteristics, such as leakage current time histories and flashover voltage. The results indicate the feasibility of icing severity assessment and flashover prediction, using the proposed model.