Time‐Domain Geoelectrical Modeling and Experimental Validation of Ground Potential Rise in Multilayer Soil Structures during Fault Events

Abstract

ABSTRACT Accurate characterization of subsurface electrical behavior during high‐energy fault events is critical for both geotechnical safety assessment and the protection of power infrastructure. This study presents a geophysically driven, time‐domain modeling framework for Ground Potential Rise (GPR) in multilayer and anisotropic soils, integrating electromagnetic field theory with physics‐informed arc resistance modeling. The methodology employs apparent resistivity profiling and soil impedance mapping, enabling high‐resolution simulation of current density and voltage gradients under realistic subsurface conditions. A coupled numerical–experimental approach is implemented: finite‐element simulations incorporating layered earth resistivity are calibrated against controlled fault injection tests using scaled grounding grids in stratified soil. The model achieves an average deviation of less than 4.7% from measured GPR and step/touch voltages, demonstrating strong predictive reliability. Results reveal that conventional steady‐state and homogeneous soil assumptions can underestimate hazardous step voltages by up to 63% and misrepresent the spatial extent of GPR zones by more than a factor of two. Comparative analyses show that optimized grounding grids reduce surface current densities by over 90% compared to isolated systems, significantly enhancing compliance with safety thresholds. Beyond its immediate application to substation and renewable energy grounding, the framework offers a transferable geoelectrical tool for infrastructure risk mapping, lightning hazard assessment, and geotechnical site evaluations in complex soil environments.