Abstract

<p>This study assesses the effectiveness of earthing protection systems across selected electrical substations within the Federal Polytechnic, Ile-Oluji, Ondo State, Nigeria. Earthing systems are vital for ensuring equipment protection, personnel safety, and overall system reliability in electrical networks. Using an earth resistance tester, ground resistance values were measured at multiple substations to evaluate performance under real operational conditions. The substations surveyed included those serving the Hostel Building, Engineering Department, Mega Substation (supporting transformers and feeders), the School of Agriculture, and the Administrative Building. Results revealed that the Hostel, Engineering, and Mega Substations exhibited low resistance values, indicating efficient grounding and compliance with safety standards. In contrast, the Administrative Building presented significantly high resistance levels, which may be attributed to poor soil conductivity, insufficient grounding rods, or suboptimal earthing design. Furthermore, lightning arresters installed at various substations—particularly those at the School of Agriculture and the Mega Substation—showed elevated resistance values. This suggests potential issues with isolated grounding configurations intended for surge protection, which may compromise their effectiveness during lightning strikes. Based on these findings, the study recommends corrective measures such as the installation of additional grounding rods, application of soil conditioning agents to improve conductivity, and a complete redesign of the grounding system for the Administrative Building. It also emphasizes the need for periodic inspection and maintenance of lightning arresters to ensure they function reliably as surge protection devices. Overall, the research highlights the critical role of continuous monitoring and proactive upgrades in maintaining effective earthing systems in substation networks, thereby safeguarding infrastructure and personnel from electrical hazards.</p>