Grounding Resistance Measurement Method Based on the Fall of Potential Curve Test Near Current Electrode

Grounding resistance is an important basic index used to ensure the safety and reliability of grounding systems. In this paper, a method for grounding resistance measurement based on the fall of potential curve is proposed that can be performed using a 2-2.5D lead wire length. In this method, the potential distribution near the auxiliary current electrode is tested and is used as the main analysis and measurement parameter. Based on the relationship between the potential distribution generated by the grounding grid and the current electrode, the grounding resistance of the grounding grid can be deduced. First, the voltages between the grounding grid and the earth surface potential near the current electrode are measured; then, the ground potential rise (GPR) of the grounding grid is calculated through theoretical analysis and numerical calculation; and finally, the grounding resistance is calculated by dividing the potential by the test current. This method avoids the complex task of accurate compensation point location required for traditional measurement methods, and can be performed easily and quickly using a short lead wire. Measurement results from spot testing show that the proposed method can meet the accuracy requirements of engineering testing.