考虑土壤非线性的输电线路暂态过电压特性研究OA

Soil non-linear effects will lead to a time-varying grounding resistance of the earthing de-vice,which in turn significantly affects the potential distribution of the transmission tower.Therefore,it is important to accurately study the transient overvoltage characteristics of transmission corridors consider-ing soil non-linear effects.A typical 220 kV transmission line transient overvoltage model considering soil non-linear characteristics is developed.Firstly,the grounded conductor lossy long line model and EMTP are integrated to construct a time-varying circuit model for grounding devices considering soil non-linear characteristics;secondly,the time-varying circuit model for grounding devices is verified through field tests;insulator strings,transmission line modules and co-tower double transmission towers are integrated to jointly construct a transient overvoltage model for typical 220 kV transmission lines consider-ing soil non-linear characteristics;finally,based on the transient overvoltage model,the transient response characteristics of typical 220 kV transmission corridor lightning strike are studied.The results show that:1)the average error between the time-varying circuit model of the earthing device and the field test results is only 3.6％,which verifies the correctness of the model;2)the time-varying circuit model of the earthing device can accurately simulate the non-linear variation characteristics of the soil,and the overvoltage at the foot of the tower drops steeply in the area near the peak of the lightning current,and the overvoltage value at the foot of the tower is lower than that of the single resistance model;3)the shorter the wave front time and the longer the wave tail time,the higher the transmission tower top potential.