Study on Dissipative Characteristics and Thermal Stability of Typical Grounding Materials in Substation

Substation grounding network in the substation to ensure the reliable operation of substation and personnel safety plays a vital role, flexible graphite composite grounding material as a non-metallic anti-corrosion grounding material has been good performance in transmission line tower grounding applications, but there are certain problems in the application of substations. In this paper, the effects of current amplitude, soil characteristics and ground position on the ground dispersion and temperature rise characteristics of flexible graphite grounding grid and traditional metal grounding grid are compared and analyzed by COMSOL Multiphysics simulation software. The simulation results show that under the action of intrusion lightning, the scattering effect of flexible graphite grounding grid and metal grounding grid is similar, the surface potential is mainly concentrated near the entry point, and the temperature rise of the grounding grid is low and there is no fusing risk. Under the action of power frequency short circuit, the maximum temperature rise of flexible graphite grounding grid is very high, which does not meet the thermal stability requirements of flexible graphite materials, and the influence of soil characteristics on the temperature rise of flexible graphite grounding grid is not obvious, and the closer the entry point is to the edge of the grounding grid, the higher the temperature rise, so in order to ensure the safe and stable operation of the grounding grid, it is necessary to improve the down conductor. The research conclusion of this paper can provide a theoretical reference for the application of non-metallic flexible graphite composite grounding materials in substation grounding networks.