高压互联电网极址土层参数对直流地表电位影响的研究

Influences of Grounding Site Soil Parameters on Earth Surface Potential of the High-voltage Interconnected Power Grid

HVDC接地极极址选择、布置形式和地表电位的分布在很大程度上取决于土壤结构模型,对分析HVDC输电系统单极运行时交流网络受到的影响也有重要作用。笔者利用CDEGS软件对HVDC系统及交流输电网络进行建模仿真,采用不同的土壤模型,分析研究了直流输电系统以单极大地回线方式运行时,各层土壤参数对地表电位分布的影响。仿真结果表明:直流地表电位因距离接地极的远近而不同,距离接地极越远,直流地表电位绝对值越小,近似呈指数函数形式衰减;直流地表电位数值与土壤厚度近似成反比,而与表层土壤电阻率近似成正比;土壤模型及参数的选取极大地影响了地表电位仿真计算的准确性及真实性,需综合考虑计算结果的精度要求和计算过程难易程度。

The HVDC grounding site selection,ground electrode design,and earth surface potential（ESP） distribution mainly depend on soil model,which is of great importance to analyze the influence of HVDC mono-polar operation with ground return on AC power grid.In this paper,the characteristics of the ESP under DC mono-polar operation mode were summarized with the software CEDGS according to the analysis of different soil models and variable soil parameters.The simulation results illustrate that the farther it is from the grounding site,the smaller the absolute value of ESP is with exponential attenuation.ESP shows approximately inverse proportion to soil thickness but direct proportion to resistivity of surface soil.Selections of soil model and its parameters exert significant influence on accuracy of ESP simulation,therefore the balance between accuracy and difficulty of calculation ought to be considered.