Optimizing Substation Grounding Design in High-Resistivity Arid Terrains: A Multi-Regional Geoelectric Analysis and Mitigation Framework

Abstract

Substation grounding in geologically complex environments is a critical safety requirement that is often compromised by high surface soil resistivity. This study evaluates the efficacy of Vertical Electrical Sounding (VES) in ensuring compliance with IEEE 80-2013 safety standards across five distinct geoclimatic zones: Tajikistan (Aeolian), Kuwait and Iraq (Alluvial/Marine), Niger (Crystalline Basement), and Saudi Arabia (Arabian Shield). Integrating field data from 62 VES stations using the Schlumberger array, 1D geoelectric models were developed to map deep conductive horizons up to 80m. The study utilizes the Reflection Factor (K) and surface resistivity (ƥ) to assess the efficiency of fault dissipation in both shallow and deep soil strata.

Computational analysis identifies a "High-Resistivity Hazard Zone" in Saudi Arabia and Niger, where resistivity routinely exceeds 800 Ὠm. In these regions, standard horizontal grounding grids result in system resistances (Rg) of 4.5 – 12.0 Ὠm, fundamentally failing the 1.0 Ὠm industrial safety threshold and significantly elevating Step and Touch potential risks. Conversely, saline basins in Iraq and Kuwait exhibit exceptional conductivity (< 15 Ὠm) but introduce a "Corrosion-Conductivity Paradox," where low resistance is counterbalanced by high galvanic corrosion rates.The findings are synthesized into a Hybrid Grounding Design Framework and a tripartite Compliance Matrix. We demonstrate that for high-resistivity sites (K<0), Deep Grounding Wells (>50m) are the only viable solution to reach stable moisture zones. For saline environments, the focus must shift from resistance reduction to material durability (e.g., tinned copper). This multi-regional approach provides a validated, non-invasive methodology for optimizing substation grounding safety in the world's most challenging geological terrains.