摘要
流注-先导转化是长空气间隙放电发展过程中最为重要的能量转化节点,针对换流站阀厅中大量存在的由屏蔽球和周围接地体组成的球-板长空气间隙类型,研究其流注-先导转化过程及机理具有重要的学术意义和工程价值。该文开展正极性标准操作冲击下球-板长间隙放电试验,利用光电联合检测系统采集放电过程瞬时光功率和电场强度等光电信息,测量流注-先导转化实测时长ta,对比由经典Gallimberti流注-先导转化模型获得的计算时长ts,发现经典模型适用于仅生成单根流注茎且注入电荷量较少的小尺寸电极放电分析;搭建考虑流注放电对流扩散和流注茎形态特征的流注-先导转化修正模型,依据电场跃升计算初始流注注入电荷量Qz和放电电流Iz,确定流注茎根数n和流注茎半径r,仿真获得流注-先导转化修正时长tsz,并与实测时长ta和计算时长ts进行对比。分析结果表明,考虑大直径电极流注茎根数及初始流注注入电荷量增多影响的流注-先导转化修正模型能显著提高计算精度。该文研究成果为今后建立更加完善的球-板长空气间隙放电先导起始模型奠定了基础。
Streamer-to-leader transition is the most important point of energy transformation during the discharge in a long air gap.Aiming at the large number of sphere-plane long air gaps that are composed of a spherical shield and surrounding earthed plane in the valve hall of converter stations,it is of great academic significance and engineering value to study the transformation process and mechanism.In this work,a sphere-plane long air gap discharge test under positive switching impulse voltage was carried out.A combined photoelectric detecting system was used to collect the photoelectric information such as instantaneous optical power and spatial electric field strength and measure duration ta of streamer-to-leader transition during discharge.Compared the measured duration ta with the calculated duration ts obtained by the classical Gallimberti streamer-to-leader transition model and found that the classical model was suitable for the discharge analysis of small-size electrodes with only one stem generated and less charge injected.A streamer-to-leader transition correction model was established considering the air gap discharge convective diffusion and stem geometric characteristics.The stem number n and stem radius r were determined according to initial streamer injected charge Qz and discharge current Iz calculated by the electric field jump.The correction duration tsz of the streamer-to-leader transition was simulated and was compared with measured duration ta and calculated duration ts.The analysis results show that streamer-to-leader transition correction model considering the effect of stem number and initial injection electric charges increasing of large diameter electrode can significantly improve calculation accuracy.The research results in this paper lay a foundation for the establishment of a more comprehensive sphere-plane long air gap discharge leader initiation model in long air gap with a large diameter electrode in the future.
作者
耿江海
陈雅茜
王平
丁玉剑
律方成
肖智勇
刘晓敏
张博禹
GENG Jianghai;CHEN Yaxi;WANG Ping;DING Yujian;LYU Fangcheng;XIAO Zhiyong;LIU Xiaomin;ZHANG Boyu(Hebei Provincial Key Laboratory of Power Equipment Security Defense(North China Electric Power University),Baoding 071003,Hebei Province,China;China Electric Power Research Institute,Haidian District,Beijing 100192,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2021年第8期2919-2928,共10页
Proceedings of the CSEE
基金
国家自然科学基金项目(面上基金项目)(51977198)。
关键词
大直径电极
流注–先导转化模型
对流扩散
流注茎
形态特征
large diameter electrode
streamer-to-leader transition model
convection diffusion
stem
morphological characteristics
