中国电力 ›› 2014, Vol. 47 ›› Issue (8): 83-87.DOI: 10.11930/j.issn.1004-9649.2014.8.83.4

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基于电磁场的杆塔接地体冲击特性计算分析

朱昌成1, 邢鹏翔2, 鲁海亮2, 蓝磊2, 冯志强2   

  1. 1. 湖北省电力科学研究院,湖北 武汉 430077;
    2. 武汉大学 电气工程学院,湖北 武汉 430072
  • 收稿日期:2014-02-16 出版日期:2014-08-18 发布日期:2015-12-10
  • 作者简介:朱昌成(1979—),男,湖北武汉人,工程师,从事高电压与绝缘技术研究。E-mail: pxxing1990@163.com

Analyses of the Impulse Characteristics of Tower Grounding Devices Based on Electromagnetic Field

ZHU Chang-cheng1, XING Peng-xiang2, LU Hai-liang2, LAN Lei2, FENG Zhi-qiang2   

  1. 1. Hubei Electric Power Research Institute, Wuhan 430077, China;
    2. School of Electrical Engineering, Wuhan University, Wuhan 430072, China
  • Received:2014-02-16 Online:2014-08-18 Published:2015-12-10

摘要: 输电线路杆塔接地体的冲击接地阻抗决定了雷击输电线路或杆塔时的塔顶电位,从而影响线路绝缘子串两端的过电压水平,直接关系到线路的耐雷水平。接地体在雷电流作用下的冲击特性表现为火花效应和电感效应,使接地体的冲击特性明显区别于工频特性。基于电磁场理论建立了输电杆塔典型接地体冲击接地阻抗计算模型,通过模型试验验证了其准确性,得到了接地体在不同土壤电阻率和射线长度下的冲击接地阻抗,并与国际著名的接地计算软件CDEGS工频接地阻抗计算结果对比分析,进一步揭示了接地体的工频和冲击特性的差异,同时验证了接地体冲击电流下存在有效长度。

关键词: 接地体, 冲击特性, 电磁场, 仿真分析, 杆塔, CDEGS, 计算模型

Abstract: Potential rise of the transmission line towers depends on the grounding resistance when the lines or towers are stricken by lightning,which determines the overvoltage between the terminals of an insulator string and the performance against lightning strike of the transmission lines. Impulse characteristics of the grounding conductors manifest as spark effect and inductive effect, which make it different from the characteristics of the power frequency. Based on electromagnetic theory, a mathematical model was built to calculate the impulse grounding resistance of a typical grounding grid for towers with different length in different soil resistivity. The accuracy of the proposed model was verified by model tests and a comparison with the calculated grounding resistance at power frequency by the well-known grounding software CDEGS further reveals the difference between power and impulse characteristics, and confirms that there is an effective length for grounding system under impulse current.

Key words: grounding system, impulse characteristic, electromagnetic field, simulation analyses, tower, CDEGS, calculation model

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