Self-consistent multi-arcs dynamic model for high voltage polluted insulators

This paper presents a self-consistent multi-arcs dynamic model for high voltage polluted insulator under impulse voltage. This model is an improvement of that one developed for single arc; it is based on an electrical equivalent circuit consisting of a series of different partial arcs and residual layer resistance. It takes into account the configuration of insulator, applied voltage polarity and the instantaneous changes of discharges parameters. The proposed model enables to compute the flashover voltage and leakage current and to show the influence of dry bands on the voltage distribution along the surface and furthermore on the electrical performance of polluted insulator. It is validated using a simple plane model in the case of uniform and non-uniform polluted bands. The computed flashover voltage and leakage current are found in good agreement with those measured experimentally.