Dynamic model of discharge propagation on polluted surfaces under impulse voltages

A predictive flashover dynamic model of polluted surfaces under impulse vol tages, i.e. bi-exponential waves simulating lightning and switching impulse voltages, is presented. It uses an equivalent electrical network and an an alytical discharge propagation criterion that has been established elsewher e. The model enables different characteristics of the discharge, such as th e current and the electrical charge, to be computed and the discharge propa gation velocity to be determined using an energetic balance. The influence of the thickness and the resistivity of the polluted layer on the discharge velocity are analysed. The obtained results are found to be in good accord ance with those obtained experimentally using an electrolytic solution mode l.