Dependency of Soil Resistivity on Soil Factors for Optimal Grounding System Performance: A Case Study of Six Sites at Funaab, Nigeria

Abstract

An efficient grounding system design for safe fault current discharge requires the knowledge of soil resistivity. This study analysed the dependency of soil resistivity ( ρ s ) on some soil factors such as soil texture (ST), moisture content (MC), temperature (T) and depth (D) for optimal grounding system operation. Two seasonal measurements of ρ s were conducted during rainy season (July 2023) and dry season (January 2024) at six different sites in Federal University of Agriculture, Abeokuta (FUNAAB), Ogun State, Nigeria as a case study. Using Herojat Rhomega-smart resistivity meter, the ρ s at the sites was measured via Wenner method. The ST and MC were determined via laboratory analysis of five 5 kg samples of soil from each site at the D values generated by the meter while T was measured using a thermometer. The ρ s dependency on MC, T and D at each site was modelled using multiple linear regression (MLR). Coefficient of determination (R 2 ) was used to determine MC, T and D contributions to ρ s . The obtained results revealed that the measured ρ s at the six sites over the study period was a function of ST, MC, T and D. The developed MLR models for the sites for both rainy and dry seasons showed that MC, T and D collectively influenced the ρ s value better than the individual factors owing to higher value of multiple R 2 observed. The outcomes of this study could be adopted as good reference points for further soil resistivity analysis and grounding system installation for FUNAAB.