4. Calculation of impedance matrix terms

4.1 Method

The method for calculating the Z _ij terms proposed here was developed at Électricité de France (EDF). It is much more general than the methods usually used, but calls on the notion of ground return currents to calculate each of the terns. In conventional methods, this notion was only necessary for the calculation of zero-sequence constants. In other words, this method takes account of the influence of the ground even in the case of direct and inverse modes (see, in this treatise, the article Corona effect on overhead electrical networks