基于脉冲定量纹影系统的正先导放电起始阶段通道瞬态温度测量  

Experimental Measurement on the Transient Temperature Evolution of Positive Initial Leader Channel Based on Pulse-Driven Quantitative Schlieren System

作　　者：程晨 陈维江 贺恒鑫 朱太云 傅中 黄煜彬 吴雨桐 Cheng Chen;Chen Weijiang;He Hengxin;Zhu Taiyun;Fu Zhong;Huang Yubin;Wu Yutong(State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology, Wuhan 430074 China;State Grid Anhui Electric Power Company Electric Power Research Institute, Hefei 230601 China;State Grid Corporation of China, Beijing 100031 China)

机构地区：[1]华中科技大学电气与电子工程学院强电磁工程与新技术国家重点实验室,武汉430074 [2]国网安徽省电力有限公司电力科学研究院,合肥230601 [3]国家电网有限公司,北京100031

出　　处：《电工技术学报》2023年第23期6483-6493,共11页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金面上项目资助(51977090)。

摘　　要：正极性先导放电特性是超特高压输变电系统操作过电压外绝缘配合和地面高目标物雷电屏蔽性能优化的基础。先导放电起始过程是流注茎向连续先导通道转化的关键阶段,通道处于非局部热力学平衡态,通道气体温度与电子密度、电场强度及径向尺寸等参数相互耦合,获取先导起始阶段通道温度演化规律对于揭示先导放电物理机制和实现全过程仿真建模至关重要。该文设计构建了一种脉冲LED光源驱动的定量纹影系统,时间和空间分辨率分别达到了0.37μs和31μm/像素,解决了长空气间隙放电通道瞬态温度时域连续测量的难题。开展了1.0 m棒-板间隙正极性先导放电观测实验,获得了放电电流、定量纹影图像及通道光学图像等数据。通过反演定量纹影图像获得了流注茎温度分布特性,发现了流注茎前端生长出一种热细通道的现象,其温度介于400~800 K,通道直径约为0.2 mm,轴向发展速度约为0.1 mm/μs。实验获得了二次流注电流注入阶段通道快速温升,以及不稳定先导弛豫阶段通道温度分布演化特性。The channel characteristic of positive leader is the basis for the switching overvoltage insulation coordination of ultra-high voltage power systems and the research of lightning discharge.The gas temperature in leader channel is an important physical parameter,which is coupled with the other channel physical quantities,such as electron density,electric field and conductivity.Obtaining the transient gas temperature of leader channel is of great significance for revealing the physical mechanism of leader discharge and supporting the equipment insulation coordination and the design of lightning shielding.Based on the transient temperature measurement theory of quantitative schlieren method,the quantitative relationship among the sensitivity,light intensity,and spatiotemporal resolution of quantitative schlieren system was deduced.A method of using a pulsed current source to drive a LED chip to generate transient strong light to improve the spatiotemporal resolution of quantitative schlieren system was proposed.A pulse-driven quantitative schlieren system for transient temperature measurement of non-local thermal equilibrium discharge channels was developed,with temporal and spatial resolutions of 0.37μs and 31μm/pixel,respectively.Compared with the highest index of general quantitative schlieren system driven by a constant power light source,the temporal and spatial resolutions were increased by 1.7 times and 2.2 times,respectively,which solved the continuous measurement problem of channel transient temperature in long air gap discharge.The experimental observations of the positive leader discharge in the 1.0 m rod-plate gap were carried out,and the data of discharge current,quantitative schlieren image,and channel optical image were obtained.The temperature distribution characteristics of stem were obtained by schlieren images:after the first streamer discharge occurred,the initial thermodynamic shape of the stem was a trapezoidal cylinder.The temperature of the stem decreased along the axial direction with the

关 键 词：先导放电 气体温度 定量纹影系统 流注茎 热细通道 不稳定先导 

分 类 号：TM851[电气工程—高电压与绝缘技术]