A Numerical Formulation for Grounding Analysis in Stratified Soils

The design of safe grounding systems in electrical installations is essential to assure the security of the persons, the protection of the equipment, and the continuity of the power supply. To achieve these goals, it is necessary to compute the equivalent electrical resistance of the system and the potential distribution on the earth surface when a fault condition occurs. This paper presents a formulation for the analysis of grounding systems embedded in stratified soils, on the basis of the boundary element method (BEM). Suitable arrangements of the final discretized equations allow the use of highly efficient analytical integration techniques derived by the authors for grounding systems buried in uniform soils. Feasibility of this approach is demonstrated by applying the HEM formulation to the analysis of a real grounding system with a two-layer soil model.