同走廊线路零序互感对线路等值零序阻抗的影响

Influence of zero-sequence mutual inductance of transmission lines of the same passage on equivalent zero-sequence impedance

以同走廊平行架设的双回线路为模型,研究线路避雷线和邻近平行线路对故障线路等值零序阻抗的影响。研究分析了线路间距、避雷线材料及运行状态等因素对线路等值零序阻抗计算的影响,并推导出基于Carson线路模型的等值零序阻抗计算方法;通过一个实例直观地比较分析各种因素的作用。理论分析与仿真计算表明,平行线路间的互感影响随间距增大而减弱,采用良导体避雷线会在一定程度上降低等值零序阻抗,同走廊线路接地检修时对故障线路参数的影响最为显著。

Based on a model of two parallel lines,this paper studies the influence of the overhead earth wire and the adjacent parallel lines on the equivalent zero-sequence impedance of fault line. The influence of such factors as distance between parallel lines,the material of overhead earth wire and the operation condition on the calculation of line equivalent zero-sequence impedance is analyzed. An algorithm of equivalent zero-sequence impedance ,which is based on Carson line model ,is given as well .Finally ,the influences of all factors mentioned above are compared through an example. Theoretical analysis and simulation indicate that the influence of mutual inductance decays with the increase of the distance between lines,a high conductivity overhead earth wire will decrease the equivalent zero-sequence impedance to a certain degree ,and groundingoverhauling of transmission lines of the same passage affects the fault line parameters the most.