一次自然雷击过程的光学观测分析  

Analysis on the Optical Observational Results of One Natural Lightning Stroke

作　　者：谷山强[1] 陈维江[2] 向念文[1] 陈家宏[1] 严碧武[1] 李涛[1] 

机构地区：[1]国网电力科学研究院,武汉430074 [2]国家电网公司,北京100031

出　　处：《高电压技术》2014年第3期683-689,共7页High Voltage Engineering

基　　金：国家自然科学基金(U1134106);国家电网公司科技项目(SG0912)~~

摘　　要：雷击过程光学观测是研究雷击放电物理过程最直观的手段，长期坚持开展自然雷击放电光学观测有助于改善我国雷击光学观测数据匮乏的现状。鉴于此，分析了一次下行先导并未与迎面先导相连接的雷击放电过程的光学观测结果。根据观测结果，获取了下行先导和迎面先导的发展轨迹，计算得到了先导发展的特征参数，包括：负极性下行先导2维发展速度为（1．98～7．28）×10^5m／s，平均值为3．78×10^5m／s；正极性迎面先导2维尺度达到56．99m，2维发展速度为4．8×1043．08×10^5m／s，持续时间为（462．5±18．5）μs。由于观测对象高度接近我国特高压同塔双回输电线路杆塔高度，观测的迎面先导发展过程可为这类线路的防雷设计提供参考。对下行先导未与迎面先导相连接的原因进行了初步分析，证实了在下行先导发展随机性的影响下，迎面先导起始并不能保证成功拦截下行先导。最后对未来开展自然雷电光学观测研究应采用的观测方法提出了建议。Optical observation is one of the most direct methods for studying lightning. Long-term optical observation of natural lightning will contribute to alleviate the scarcity of lightning＇s optical observation data in China. Hence, we ana- lyzed the data of a natural downward lightning flash recorded by high speed CCD （charge-coupled-device） camera, in which the downward negative leader did not connect with the upward leader started from a tall building. Using the record data, we obtained the progressing track of the two leaders and hence calculated their characteristic parameters： the 2-D velocity range of negative downward leader main channel is （1.98 ×105-7.28 × 105） m/s, with an average of 3.78 × 105 m/s; the non-connecting upward leader developed to 56.99 m with its 2-D velocity within （4.8×104-3.08× 105） m/s in a duration of （462.5± 18.5） μs. Since the height of object under observation is close to the towers of the 1 000 kV double-circuit UHV transmission lines China, the data of upward leader development provide a reference for the lightning protection design of these power lines. We preliminarily analyzed the phenomena that the downward leader did not reach the upward leader, and confirmed that the initiation and development of an upward leader could not guarantee the successful capture of its counterpart downward leader, due to the randomness of the downward leader＇s development.

关 键 词：雷击过程 光学观测 迎面先导 下行先导 发展轨迹 发展速度 持续时间 

分 类 号：O461[理学—电子物理学]