Dynamic model of discharge propagation on polluted surfaces under impulse voltages

A predictive flashover dynamic model of polluted surfaces under impulse voltages, i.e. bi-exponential waves simulating lightning and switching impulse voltages, is presented. It uses an equivalent electrical network and an analytical discharge propagation criterion that has been established elsewhere. The model enables different characteristics of the discharge, such as the current and the electrical charge, to be computed and the discharge propagation 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 accordance with those obtained experimentally using an electrolytic solution model.