有限面积下并行线路杆塔接地网级联降阻及电位分布特性研究

Characteristics of Resistance Reduction and Potential Distribution of Parallel Line Tower Grounding Grid Cascaded in Limited Area

现行输电线路杆塔接地施工往往受制于耕地植被、道路建筑、征地赔偿成本等原因无法采用外延降阻。针对有限施工面积条件下杆塔接地网的接地降阻问题,提出并行输电线路杆塔级联接地降阻策略并验证其可行性。首先,建立相邻输电线路杆塔接地网级联接地散流计算模型,通过仿真分析了接地材料参数、级联引线长度、土壤电阻率、入地电流频率等因素对接地电阻的影响规律;然后,对比分析级联接地模型与方框外延接地模型的降阻效率;最后,分析了相邻杆塔接地网级联条件下的导体电位分布特征。计算结果表明:相比于传统的方框外延降阻方式,采用级联接地结构的相邻杆塔降阻效率更高;级联接地网的散流特征受入地电流频率和材料参数影响较大;相邻杆塔接地网级联增大了电流的散流区域并降低受雷线路的塔顶电位。

The current grounding construction of transmission line pole towers is often restricted by cultivated land vegetation,road construction,land acquisition compensation costs and other reasons,and cannot be extended to reduce resistance.Aiming at the grounding resistance reduction problem of the pole tower grounding grid under the condition of limited construction area,the author proposes a cascaded grounding resistance reduction strategy for adjacent transmission line pole towers and verifies its feasibility.Firstly,a calculation model of dispersion current of adjacent transmission line pole tower grounding grid cascade is established,and the influence of grounding material parameters,cascaded lead length,soil resistivity,and grounding current frequency on grounding resistance is analyzed through simulation calculation.Then,the resistance reduction efficiency of the cascaded ground model and the box extension ground model is compared and analyzed.Finally,the conductor potential distribution characteristics under the condition of cascaded grounding grids of adjacent pole towers are analyzed.The calculation results show that:Compared with the traditional box-extended resistance reduction method,adjacent towers with cascaded ground structure have higher resistance reduction efficiency.The current dissipation characteristics of the cascaded grounding grid are greatly affected by the frequency of the grounding current and the material parameters.And the cascaded grounding grids of adjacent towers increases the current dissipation area and reduces the tower top potential of the lightning line.