Proximity effects on the ground fault current distribution within the earthing system formed by a substation and the associated transmission lines

The analysis of currents flowing through a substation earth electrode and through earth wires of overhead lines, connected to the substation for ground faults within the substation, is performed, including the proximity effects between the substation and the earth electrodes of the line towers. Comparison of the results obtained using the complete model suggested by the authors, with the results obtained ignoring the proximity effects, for typical cases, has shown that the proximity of the earth electrodes might considerably affect the ground current distribution and therefore it must be taken into account in certain circumstances. Relatively simple expressions are derived for evaluation of currents flowing through different parts of earthing systems that cover the proximity effects