Development of a fractal-based model for simulating streamer flashover of insulating surfaces

A fractal-based model for simulating the final stage of positive streamer flashover is introduced. The proposed model considers the stochastic nature of discharge growth along insulating surfaces and integrates physical criteria on surface discharge propagation. An application of the proposed model to simulate flashover along a Polyethylene (PE) insulating specimen bridging a short sphere-ring air gap has been made. With reference to experimental results, the proposed model well predicts the flashover voltage and spark path along the insulating surface. The statistical dispersion of the flashover voltage and spark path should be accounted for in determining the creepage distance of insulators utilized in critical electronic equipment.