Flashover dynamic model of polluted insulators under ac voltage

This paper presents a dynamic model allowing the prediction of discharge ac tivity leading to flashover of polluted insulators. It takes into account t he instantaneous changes of the discharge (arc) parameters. For a given vol tage, geometry and pollution severity, the model enables one to determine t he following parameters: temporal evolution of the current, are resistance, propagation velocity, charge injection and flashover time lag. The flashov er voltage characteristic as a function of the surface conductivity of insu lators calculated by this model is quite satisfactory in contrast to the em pirical and semi-empirical models reported in the literature. The leakage c urrents computed by our model are found to be in a good agreement with thos e measured in the laboratory.