华南理工大学学报(自然科学版) ›› 2023, Vol. 51 ›› Issue (12): 73-82.doi: 10.12141/j.issn.1000-565X.230035

所属专题: 2023年能源、动力与电气工程

• 能源、动力与电气工程 • 上一篇    下一篇

架空线路断股缺陷的轴向温升特性及识别方法

蒋兴良1,2 黄武鸿1,2,3 廖乙1,2 张志劲1,2 胡建林1,2   

  1. 1.重庆大学 雪峰山能源装备安全国家野外科学观测研究站,重庆 400044
    2.重庆大学 输配电装备及系统安全与新技术国家重点实验室,重庆 400044
    3.国网湖南超高压变电公司,湖南 长沙 410100
  • 收稿日期:2023-02-06 出版日期:2023-12-25 发布日期:2023-03-28
  • 作者简介:蒋兴良(1961-),男,教授,博士生导师,主要从事高电压绝缘技术、气体放电以及输电线路覆冰及其防护研究。E-mail: xljiang@cqu.edu.cn
  • 基金资助:
    国家自然科学基金重点项目(51637002)

Axial Temperature Rise Characteristics of Overhead Line Broken Strand Defects and Identification Method

JIANG Xingliang1,2 HUANG Wuhong1,2,3 LIAO Yi1,2 ZHANG Zhijing1,2 HU Jianlin1,2   

  1. 1.Xuefeng Mountain Energy Equipment Safety National Observation and Research Station,Chongqing University,Chongqing 400044,China
    2.State Key Laboratory of Power Transmission Equipment & System Security and New Technology,Chongqing University,Chongqing 400044,China
    3.State Grid Hunan Extra High Voltage Substation Company,Changsha 410100,Hunan,China
  • Received:2023-02-06 Online:2023-12-25 Published:2023-03-28
  • About author:蒋兴良(1961-),男,教授,博士生导师,主要从事高电压绝缘技术、气体放电以及输电线路覆冰及其防护研究。E-mail: xljiang@cqu.edu.cn
  • Supported by:
    the Key Program of National Natural Science Foundation of China(51637002)

摘要:

运行中的户外架空输电线路断股缺陷将引发局部过余温升,温度极大值出现在缺陷处,并向无缺陷区域迅速衰减。基于温度分布的红外热成像技术能识别断股缺陷程度,但不同的风速会显著影响观测对象表面温度,为红外热像检测带来困难。为研究低风速下架空线路断股处轴向温度分布,以LGJ-240/30钢芯铝绞线为例,在重庆大学输配电装备及系统安全与新技术全国重点实验室的人工气候室对其进行热循环试验。通过人工破坏制造断股缺陷,利用自制集风装置调节风速,交流大电流发生装置提供稳定的焦耳热源,得到断股数对线路缺陷背侧最大温升与轴向无缺陷区域温差的影响规律,并基于此提出风速为1~3 m/s时,线路断股数红外识别方法,最后通过在雪峰山能源装备安全国家野外科学观测研究站进行自然实验对该方法进行验证。结果表明:架空输电线路发生断股后,缺陷温度极大值与非缺陷区域正常温度的轴向温差随风速增大迅速减小;轴向温差θ和风速u拟合关系式中,描述传热项的拟合系数b随载流量、断股数增加而增加;在低风速条件且线路载流量为360、480及600 A,断股数大于3时,通过提出的方法断股数识别准确率大于90.1%,断股缺陷识别率大于94%,解决了低风速下红外热巡检工程无法实施而错失最佳检修时间的难题,使线路检修效率大幅提高,从而保障电网安全稳定运行,对架空输电线路红外热巡检工程具有指导意义。

关键词: 架空输电导线, 断股程度识别, 热循环试验, 红外热成像

Abstract:

Defects in operating outdoor overhead transmission lines with broken strands will cause local excess temperature rise. The maximum temperature occurs at the defect and decays rapidly to a defect-free area. Infrared thermography based on temperature distribution can identify the degree of broken strands defects. However, the wind speed will significantly reduce the surface temperature of the observed object, making infrared detection difficult. To study the axial temperature distribution at the broken strand area of overhead lines under low wind speed, the paper took the LGJ-240/30 type steel-cored aluminum strand as an example, and conducted thermal cycling tests in the State Key Laboratory of Power Transmission Equipment & System Security and New Technology of Chongqing University. The broken strand defect was produced by manual destruction, the homemade wind speed was regulated by the air collecting device, and the AC large current generator provided a stable Joule heat source. The influence of the number of broken strands on the maximum temperature rise at the back of the defect and the temperature difference in the axial defect-free area was obtained. And based on this, the infrared identification method of broken strand number when the wind speed is 1~3 m/s was proposed. Finally, the method was verified by natural experiments in the National Field Science Observation and Research Station. The results show that after the occurrence of strand breaks in overhead transmission lines, the axial temperature difference between the extreme value of the defective temperature and the normal temperature in the non-defective area decreases rapidly with the increase of the wind speed; the fitting coefficient b, which describes the heat transfer term in the fitting equation of the axial temperature difference θ and the wind speed u, increases with the increase of current carrying capacity and the number of strand breaks. The proposed method has a recognition rate of more than 90.1% for the number of broken strands and more than 94% for defects under the condition of low wind speed, the load current is 360, 480, and 600 A, and the number of broken strands is more than 3. It solves the problem of infrared thermal inspection project under low wind speed without missing the best maintenance time, greatly improves the maintenance efficiency of line maintenance, guarantees the safe and stable operation of power grid, and has guiding significance for the infrared thermal inspection project of overhead transmission lines.

Key words: overhead transmission line, broken strand degree identification, thermal cycling test, infrared thermography

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