Effect of a Two-Layer Earth on the Electric Field Near HVDC Ground Electrodes

Analysis of the potential and field distribution in the vicinity of HVDC ground electrodes has-till now been confined to the-case of homogeneous earth. However, the case of an electrode buried in non-uniform earth is of greater practical interest. In most practical cases, the resistance variation of the earth may reasonably be characterised by a two-layer earth model, comprising a top layer of finite depth followed by a layer of different resistivity extending practically down to infinity.