摘要
厘清雷击作用下地面物体上行先导的起始物理机制,是防雷系统分析设计以及提升防护性能的重要基础。在现有先导发展模型基础上,该文纳入雷电下行先导发展速度对上行先导起始的影响作用,给出单位长度上行先导发展所需电荷量与先导发展速度的关系,并改进稳定先导的起始条件,建立负极性雷击下的上行先导发展模型。通过模拟风电机组不同位置的上行先导起始情况,指出稳定上行先导起始时,其初始流注长度存在某个临界值。由此提出判别稳定先导起始的初始流注动态临界长度判据,即地面物体附近空间背景电势曲线和流注区域电势曲线的交点横坐标(初始流注长度)超过临界值时,稳定上行先导起始。长间隙放电与实际雷电观测结果验证了该判据的有效性和正确性。该判据显著简化了上行先导起始的判断过程,拓展了现有平均背景电场判据和临界长度判据的概念,并指出动态临界长度受雷电下行先导发展速度和雷电流峰值的共同影响。通过与已有上行先导起始判据的交互比较发现,所提判据能更好地模拟地面高大物体(如风电机组)的上行先导起始过程,可为雷击防护系统优化设计提供理论和方法依据。
The mechanism of the upward leader inception is the fundamental for the design and analysis of the grounding structure lightning protection.In this paper,an improved leader propagation model was proposed,which takes the influence of the downward leader velocity,the increasing of the charge required to sustain the leader with the speed,into account.The criterion for the stable leader inception was also improved.The model was used to analyze the upward leader inception from the wind turbine blade.The results show that there is a critical length for the initial streamer when the stable leader starts.Therefore,the dynamic critical length criterion of initial streamer was proposed for the inception of upward leader from grounding structure.The criterion indicates that the upward leader initiates,when the value of the x-coordinate for the intersection of the background potential curve and the streamer potential curve,called the length of the initial streamer,exceeds the critical value.The model was verified by the field observation of the natural lightning and the experimental results of the long sparks.The new criterion simplified the calculation of upward leader inception dramatically.It also extends the existing average background electric field method and the critical length criterion.Both the velocity of downward leader and the peak current of the lighting stroke have the influence on the dynamic critical length.By the comparison between the proposed criterion and the existing ones,it can be found that the criterion proposed in this paper can provide a better analytical tool for the lightning protection system of taller structures,such as modern wind turbines.
作者
郭子炘
李庆民
于万水
李宏博
张黎
Siew Wah Hoon
GUO Zixin;LI Qingmin;YU Wanshui;LI Hongbo;ZHANG Li;SIEW Wah Hoon(State Key Lab of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China;School of Electrical Engineering,Shandong University,Jinan 250061,Shandong Province,China;Department of Electronic&Electrical Engineering,University of Strathclyde,Glasgow G11XQ,UK)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2020年第5期1713-1722,共10页
Proceedings of the CSEE
基金
国家自然科学基金项目(51420105011).
关键词
先导发展模型
上行先导起始
动态临界长度
雷击防护
雷电屏蔽性能
leader propagation model
upward leader inception
dynamic critical length
lightning protection
lightning shielding performance
作者简介
郭子炘(1992),男,博士研究生,从事风力发电机组雷击防护方面的研究工作,guoxicin@126.com;李庆民(1968),男,教授,博士生导师,从事高电压与绝缘技术、放电物理等领域的研究工作,lqmeee@ncepu.edu.cn。
