Evaluation of Grounding Resistance and Inversion Method to Estimate Soil Electrical Grounding Parameters

Abstract

Soil resistivity plays a key role in designing grounding systems for high-voltage transmission lines and substations. The objectives of this paper are to determine the best estimated value of the apparent resistivity or electrode grounding resistance of N-layer soil and to use a new inversion method to precisely determine earth parameters. The inversion of electrical sounding data does not yield a unique solution, and a single model to interpret the observations is sought. This paper presents a new inversion method to statistically estimate soil parameters from Schlumberger and Wenner measurements. To validate the method and test the inversion scheme, four soundings were selected: two theoretical and two in the field. The procedure was applied using test data and a satisfactory soil model was obtained.