Dynamic model of a surge arrester for computer calculation of lightning performance of substations

The characteristics of the silicon carbide blocks of surge arresters are time-dependent because of the inductance and negative temperature coefficient of the silicon carbide. A simple but realistic model to express these characteristics is proposed. The model, developed from routine test results, represents the decay in discharge voltage as time-dependent instead of separating it into inductive and heating effects. Using this model, the effect of a lightning stroke to a gas-insulated substation, under various conditions, is analysed by a computer program to show that the method adopted to represent the block characteristics has an effect on the calculated overvoltages.