Equivalent resistivity of non-uniform soil for grounding grid design

This paper develops a method to determine the equivalent resistivity of heterogeneous soils to be used in the available expressions for uniform soils employed to calculate the ground resistance, mesh and step voltages of substation grounding grids. The results obtained with the proposed equivalent resistivity are compared with the results obtained from the two layer and the multilayer models of the soil and with the results from a computer program, developed by the authors, directly based on the potential produced by a point source in heterogeneous soil.<
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