A Mathematical Method for Determining Optimal Quantity of Backfill Materials Used for Grounding Resistance Reduction

Abstract

During installation of grounding system, which represents a significant part of any electrical power system, various backfill materials are used for grounding resistance reduction. The general mathematical method for determining an optimal quantity of backfill materials used for grounding resistance reduction, based on the mathematical tools, 3D FEM modeling, numerical analysis of the obtained results, and the "knee" of the curve concept, as well as on the engineering analysis based on the designer's experience, is developed and offered in this paper. The proposed method has been tested by applying it to a square loop enveloped by a backfill material and buried in a 2-layer soil. The results obtained by the presented method showed a good correlation with the experimentally obtained data from literature. The proposed method can help the designers to avoid the saturation areas in order to maximize efficiency of backfill material usage.