Grounding Performance Analysis of Reinforced Concrete Grounding System of Cable Tunnel

In order to master the grounding performance of the cable tunnel reinforced concrete and optimize the grounding design of underground cables, taking a 110kV cable tunnel as an object, a cable total grounding grid model composed of cable tunnel reinforced concrete and grounding grids of substations at both ends is established, and the grounding resistance, current and potential distribution of cable grounding wires, contact potential difference and step potential difference in the cable tunnel and on the ground surface along the tunnel and the substations at both ends are calculated and analyzed. The results show that the grounding resistance of the cable tunnel reinforced concrete and the total grounding grid is about 0.1Ω, which meets the relevant grounding resistance requirements of cable grounding. In case of short circuit fault, the current mainly enters the ground from the grounding wires at both ends, which may account for more than 90%. The potential rise of the grounding strip is U-shaped. The maximum contact potential difference and step potential difference appear on the surface of substations at both ends, and the maximum potential difference can meet the requirements of personal safety.