Calculation of the induced effects due to a lightning stroke

A method for computing the effects of a direct lightning stroke on the protection system of an industrial building is presented. The proposed method is based on a `circuit-approach´. The lightning protection system and the `victim´ circuits are simulated by means of an equivalent electrical network formed by resistances, inductances and capacitances, having all the branches coupled together. The lightning stroke is simulated by means of an ideal current source characterised by a pulse waveshape. Propagation phenomena are considered and the ionisation phenomena in the soil are taken into account by a nonlinear current-dependent electrical model, function of the electrode´s shape and the ground resistivity. Two distinct points of impact of the lightning stroke to the protection system are considered. An analysis, in the frequency and in the time domain, of effects such as step voltages of EMF induced on power cables, coaxial cables, and loops is performed