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500kV架空线路雷电过电压与冲击接地电阻关系研究

甘艳1,张昌2,黄瑞莹1   

  1. 1. 武汉大学
    2. 国家电网公司华中分部
  • 收稿日期:2017-07-10 修回日期:2018-05-09 发布日期:2018-08-21
  • 通讯作者: 黄瑞莹

Research on Relationship Between Lightning Overvoltage and Impulse Grounding Resistance of 500kV Transmission Line

  • Received:2017-07-10 Revised:2018-05-09 Published:2018-08-21

摘要: 雷击事故严重影响500kV输电线路的安全运行。本文建立三维场-路结合模型,对500kV输电线路、杆塔以及接地网进行一体化建模。基于全波电磁暂态模型,从冲击接地的概念出发,将土壤电阻率、雷电流波前时间和幅值对雷电过电压直接反映在雷电过电压值上,对雷电过电压与冲击接地电阻计算公式进行拟合。研究表明,所建立的输电线路-杆塔-接地网一体化模型在对雷电过电压计算中更为先进和准确。同时,波前时间减小和土壤电阻率增大均会使冲击接地电阻值与雷电过电压增大。不考虑火花效应时的冲击接地电阻值与雷电流幅值无关,雷电过电压随雷电流呈正比例增大。在进行接地网设计时,应考虑能使雷电过电压值下降的接地网射线有效长度。本文可以为500kV输电线路防雷提供指导。

关键词: 500kV输电线路, 雷电过电压, 一体化模型, 冲击接地电阻值

Abstract: Lightning accident often occurs on 500kV transmission line, which influences on safe operation seriously. To explore the relationship between lightning overvoltage and impulse grounding resistance, we establish an integrated model. According to field-circuit coupled method, a transmission line-tower-grounding grid was setting up. The influence of earth resistivity, lightning current wave front time and amplitude was study. The experimental equations about lightning overvoltages were developed in the meantime. We established an expression of the relationship between lightning overvoltage and impulse grounding resistance. Study shows that the decrease of lightning current wave front and increase of earth resistivity would increase the value of impact grounding resistance and lightning overvoltage. Impact grounding resistance has no relationship to lightning current amplitude but lightning overvoltage has a variation of direct proportion with amplitude. We should consider the effectively length of grounding grid when design grounding grid. This research can provide guidance on lightning protection of 500kV transmission line.

Key words: 500kV transmission line, lightning overvoltage, integrated model, impulse grounding resistance