Research on Performance of Grounding Conductor Based on Multi-Physics

Abstract

The performance analysis of the grounding conductor is of great significance for improving the design and construction level of the grounding grid and rationally selecting the grounding conductor specifications.Based on the multi-physics analysis and calculation software COMSOL, this paper establishes a three-dimensional simulation model of the grounding conductor with the standard hexagonal M8 bolt as the research object.Firstly, the contact resistance of the grounding copper bus contact surface is calculated, and the influence of contact resistance is analyzed according to different factors. Then, the influence of different tightening torque on the maximum temperature of the contact surface under the condition of short-circuit current is calculated. Finally, the normal condition of the contact surface under different tightening moments and the pressure distribution characteristics during short-circuit are calculated. The results show that the bolt tightening torque, the surface roughness of the copper row, the selected grounding copper row material, and the overlapping area all have an effect on the contact resistance; When the grounding conductor is short-circuited, the maximum temperature on the contact surface decreases with the increase of the tightening torque. It is recommended to use copper as the material of the grounding conductor, and apply a tightening torque to the bolt at 24∼28N•m; At the same time, the distribution characteristics of the contact surface of the conductor under normal conditions are analyzed. Finally, based on the research results, the method of reducing the grounding resistance at the grounding conductor joint in practical engineering is proposed.