Study on the Grounding Characteristics of Power Transmission Tunnels in Complex Terrain

Power transmission through pipeline corridors assumes a pivotal role in overcoming challenges associated with the exportation of new energy, wherein the grounding system profoundly impacts the secure functioning of equipment. In this investigation, employing CDEGS modeling, a comprehensive examination was conducted to systematically scrutinize the influence of soil resistivity, corridor length, and the span distance between the through-conductor and the principal structural reinforcement on the electrical characteristics of the grounding system within power transmission corridors. The research outcomes reveal that an escalation in soil resistivity triggers a linear upsurge in ground impedance, manifesting a notably accelerated growth rate in shorter corridors. Furthermore, elongating the corridor length exhibits a mitigating effect on the system's ground impedance; nonetheless, the law of diminishing returns becomes discernible when the corridor length surpasses 4 km. The reduction of the cross-bonding distance between the through-conductor and the main structural reinforcement emerges as an effective strategy for diminishing the system's ground impedance, with a range of 100–125 m identified as the most optimal for cross-bonding. The study convincingly illustrates that within high-resistance, long-distance environments, the corridor grounding system adeptly governs the voltage distribution within the corridor. This not only furnishes theoretical underpinning for the refinement of grounding schemes in power transmission corridors situated in high-resistance regions but also substantively contributes to the assurance of the secure and stable operation of these crucial conduits for energy transmission.