Grounding Grid Resistance Estimation in Non- Homogeneous Soils: A Study Focused on Equivalent Analytical Models

This paper deals with the effects of soil inhomogeneity in the equation that describes the grounding resistance. This issue is relevant in order to circumvent the classical assumption that the soil is homogeneous and that the equivalent geometry of the grid is hemisphere. As the medium homogeneity is a rare condition in real soils, supported by the Average Potential Method and by the Images Theory, a derivation in the existing analytical formulation to calculate the grounding resistance in non-homogeneous soils is proposed for different equivalent grounding systems. The study is validated and supported by simulations performed in the software Ansys Maxwell 3D.