Lightning protection zones estimation for a power station using the elliptic model

Protection against lightning strokes is one of the key parameters in terms of reliability of power systems. Rolling sphere method (RSM) is nowadays one of the most popular methods used for dimensioning the lightning rod protective system of power stations. Although very used, this method neglects some of the most important parameters of the lightning attachment process to grounded objects thus resulting unrealistic dimensions of the protective zones. In this paper an elliptical model is proposed in order to estimate the lightning protection zones for a typical power station of Romanian's national grid. The obtained results are compared with those proposed by the rolling sphere method.