Accurate Measurement of Tower Grounding Resistance for Single-Tower and Multi-Tower Parallel Scenarios Based on the Clamp Meter Method: For the Sustainable Operation of Towers

Transmission tower grounding safety is a critical element that significantly impacts the reliability and sustainability of power grids. Tower grounding resistance is a significant grounding characteristic parameter. In order to accurately measure the grounding resistance of towers using the clamp meter method in both single-tower and multi-tower parallel scenarios, this paper establishes theoretical calculation models for measuring tower grounding resistance using the clamp meter method. Considering the interaction between the artificial grounding device and the tower foundation, this paper models and simulates transmission towers and lightning shield wires, analyzing the influencing factors on the grounding resistance measurement results using the clamp meter method in both single- and multi-tower parallel scenarios. The results show that for single towers, the clamp meter measurement results increase with decreasing foundation root spacing and increasing length of the artificial device’s extension lines, but the changes are relatively small. In multi-tower grounding scenarios, due to the shunting effect of the parallel branches formed by the towers and lightning shield wires, the value is smaller than in single-tower grounding scenarios. Changing the number of parallel towers and the type of lightning shield wire produces little effect on the measurement results. However, changes in soil resistivity have the most significant impact. Therefore, correction formulas for the impact of soil resistivity on clamp meter measurements are proposed and then verified by applying them to field tests.