Modelling of AC arc process on an ice surface

By considering the arc as a time-dependent impedance, constituted of a resistance in series with an inductance, a dynamic model has been derived to simulate the arc behavior on iced-insulator surfaces. The non-LTE model used for the arc channel resistance, is obtained by the combination of heat transfer equation of the channel and the electrical network relations. The inductance is deduced from electromagnetic fields calculations. The not bridged ice-layer part, is replaced by an equivalent resistance, where the surface conductivity is calculated by taking into account the effect of melting water due to the heat dissipated from arc. This model takes into account some main parameters such as insulator geometry and the freezing water conductivity. The model enables to calculate the flashover voltage from which, some major parameters such as propagation velocity, leakage current, and arc channel radius are calculated. The validity of the model was verified by comparing the computed and experimental results. Good correlation has been found between them.