Evaluation Method of Impulse Discharge Performance of Ground Electrode Based on Soil Discharge Image

摘要

When impacted by lightning current, the impulse dispersion performance of the grounding device is significantly affected by the dispersion performance of soil near the ground electrode. This effect is mainly reflected by the phenomenon of soil spark discharge. At present, engineers use the empirical formula to convert the soil spark discharge to the impulse coefficient of impulse grounding resistance. Therefore, there is no available quantitative analysis method to evaluate soil impulse dispersion performance. To solve this problem, we present an evaluation method for the impulse discharge efficiency of soil by using X-ray images, define $V_{I}$ as the parameter, which is the volume of discharge region to the ratio of the peak impulse. Then, the rationality and validity of the method are verified. Finally, the variation rules of impulse discharge efficiency are analyzed in different soil. Results show that the $V_{I}$ can reflect the impact of soil medium property on the grounding device impulse discharge efficiency more clearly, and this parameter provides a new idea for enhancing the impulse dispersion performance of soil near the ground electrode.