Earth surface potential and grounding resistance for grounding grid in two-layer model soil

Computerized grounding analysis in uniform and two-layer soil types became widespread in the eighties, mainly because of the enhanced accuracy, speed and flexibility afforded by the use of modem computers. In this paper, an old but more accurate and practical technique is used for calculating the grounding resistance (Rg) as well as the Earth Surface Potential (ESP) of the grounding grids in two-layer soil which based upon the apparent resistivity of the two layer soil. This technique is based on the Current Simulation Method (CSM). This technique is used because of the current distribution on the electrode is not uniform when this current is injected into the grounding grid. The Current Simulation Method is analogous to the Charge Simulation Method. The validation of the method is described by a comparison with the results in literatures.