Simulation of surface charge effect on impulse flashover characteristics of outdoor polymeric insulators

Effect of pre-deposited surface charges on impulse flashover characteristics of a polymeric insulator is studied by means of computer simulations utilizing a model based on criteria for streamer inception, propagation and sustenance. A parametric study is performed to investigate the influences imposed by magnitude and polarity of the charge, its location on insulator surface and properties of insulator material on its flashover voltages. The obtained results are analyzed in terms of electric field distributions in the vicinity of the insulator surface and are compared with experimental data available in the literature.