水源区杆塔外敷电极条件下的基础接地特性

水电变电站出线段杆塔接地施工往往受地形和征地条件制约,研究水源区杆塔桩基散流特性并提高桩基自然接地的散流能力对水源区电力线路防雷具有实际意义。本文采用COMSOL Multiphysics软件建立水源区杆塔桩基散流模型,提出基于桩基外敷柔性电极的基础散流优化方法,分别对杆塔桩基在柔性电极不同外敷面积、不同外敷半径和不同连接位置条件下的基础接地电阻、桩基内钢筋电流密度以及外敷电极电流密度进行计算。研究表明：桩基外敷柔性电极对于改善桩基内钢筋散流有明显效果,外敷柔性电极的敷设面积、敷设位置、敷设半径等是影响桩基散流特性的重要因素,改善外敷柔性电极的布置方式有利于降低杆塔基础的接地电阻值。本文仿真计算相关结论可为水源区输电线路杆塔接地设计与降阻改造提供参考。

Study on Tower Foundation Grounding Characteristics with External Electrode in Water Source Area

The grounding construction of pole towers in the outgoing section of hydropower substations was often restricted by terrain and land acquisition conditions. Studying the dispersion characteristics of the pile foundation in the water source area and improving the natural grounding dispersion capacity of the pile foundation had practical significance for lightning protection of power lines in the water source area. In this paper, COMSOL Multiphysics software was used to establish the divergent flow model of the tower base in the water source area. A method for optimizing the foundation divergence based on a flexible electrode applied to the pile foundation was proposed. The grounding resistance, the current density of the reinforcement in the pile foundation and the current density of the external electrode were calculated. The research shows that the external application of flexible electrodes on the pile foundation has a significant effect on improving the dispersion of the steel bars in the pile foundation. The laying area, location, and radius of the externally applied flexible electrodes are important factors affecting the dispersion characteristics of the pile foundation. The method is beneficial to reduce the grounding resistance of the tower foundation. The relevant conclusions of the simulation calculation in this paper can provide a reference for the grounding design and resistance reduction of transmission line towers in the water source area.