Distribution of zero sequence currents for earth faults occurring along a transmission line and proximity effects

A relatively simple procedure is suggested for the evaluation of the distribution of zero sequence currents, within the earthing system of a substation, for earth faults occurred along a line coming from the substation. The earthing system model derived takes into account all relevant phenomena including the mutual influence among earth electrodes through the soil to cover the proximity effects which were shown to be significant in certain cases. The procedure suggested is applied to a practical case, for illustration.