Analysis the Influence of Corrosion layer on the Grounding Performance of Grounding Electrodes

The grounding electrode buried in soil is prone to corrosion affected by soil and leakage current. The surface of corroded grounding electrodes is wrapped with corrosion product, which affects the normal current dissipation process and weakens the grounding performance. The accurate analysis of the grounding performance with corrosion layer can lay a solid theoretical basis for the safety of the power system. In this study, the corrosion layer is regarded as a layer of conductive medium between the electrode and soil. The leakage current along the electrode and the charge on the interface are analysed by coupling point matching method with boundary element method. Finally, the leakage current, grounding resistance, ground potential rise (GPR) and the step voltage of the two typical electrodes with corrosion layer are investigated. The results show that the corrosion layer causes the reduction of the leakage current at the end of the electrode and the enhancement of the leakage current in the middle location. Furthermore, the corrosion layer causes the increase of the grounding resistance and GPR, and the decrease of the step voltage. In addition, the influence of the reduced radius on the grounding performance is much smaller than that of the corrosion layer.