不同电极结构下SF_(6)气体临界击穿场强计算  

Calculation of Critical Breakdown Electric Field Strength of SF_(6) Under Various Electrode Configurations

作　　者：李晓蔚 杭玉桦 刘韬[2] 朱斌[2] 赵玮玉 LI Xiaowei;HANG Yuhua;LIU Tao;ZHU Bin;ZHAO Weiyu(Daya Bay Nuclear Power Operations and Management Co.,Ltd.,Guangdong Shenzhen 518000,China;Suzhou Nuclear Power Research Institute,Jiangsu Suzhou 215004,China;State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]大亚湾核电运营管理有限公司,广东深圳518000 [2]苏州热工研究院有限公司,江苏苏州215004 [3]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《高压电器》2022年第3期107-114,共8页High Voltage Apparatus

基　　金：江苏省基础科技计划(自然科学基金)(BK20190187)。

摘　　要：SF_(6)气体在电力绝缘设备中的应用已经非常广泛,计算多种电极结构下SF_(6)气体临界击穿场强对于研究SF_(6)气体放电击穿特性具有重要意义。文中针对SF_(6)气体在多种电极结构下的放电击穿过程开展了详细的理论研究与计算分析。首先,基于已有的SF_(6)气体击穿过程进行理论总结并加以完善;然后,引入阶段先导发展模型,针对稍不均匀电场条件下SF_(6)气体放电击穿过程进行建模,将放电击穿分为3个主要过程:首电子产生阶段、流注初始阶段及先导发展至击穿阶段;最后,结合气体物性参数建立多种电极结构下SF_(6)气体折合临界击穿场强计算综合模型,计算得到SF_(6)气体在多种电极结构下的临界击穿场强。研究表明:相同压强情况下,交流电压下的临界击穿场强要比雷电冲击电压下的折合临界击穿场强低。雷电冲击电压下临界击穿场强极性随电极结构和压强条件的变化而改变。并且,受电极曲率较大处局部放电所产生空间电荷的影响,随着压强的增大和突出物尖端的加长,正极性雷电冲击电压下的临界击穿场强趋向施加交流电压下的临界击穿场强。The application of SF_(6) gas in electric insulation equipment has already widespread.It is of great signifi⁃cance to calculate the critical breakdown field strength of SF_(6) under various electrode configurations for the study of discharge breakdown characteristic of SF_(6).In this paper,detailed theoretical studies and calculation analysis of breakdown of SF_(6) gas under various electrode configurations are performed.Firstly,based on the existing SF_(6) break⁃down process,the theory is summarized and improved;then,the step lead development model is introduced to mod⁃el the discharge breakdown process of SF_(6) under slight non⁃uniform electric field.The discharge breakdown is divid⁃ed into three main stages:The first electron generation stage,the streamer inception stage and the lead development till breakdown stage.Finally,the comprehensive model for calculation of converted critical breakdown field strength of SF_(6) gas at various electrode configurations is set up with combination of physical parameter of the gas and the criti⁃cal breakdown field strength of SF_(6) gas under multiple electrode configurations is obtained.It is shown by the study that under the same intensity of pressure condition,the critical breakdown field strength under AC voltage is lower than the converted critical breakdown field strength under lightning impulse voltage.The polarity of critical break⁃down field strength under lightning impulse voltage changes with the change of electrode structure and intensity of pressure conditions.Also,due to the influence of space charge generated by the partial discharge at the electrode with large curvature and with the increase of intensity of pressure and the lengthening of the tip of a projection,the critical breakdown field strength under the positive lightning impulse voltage tends to that of applying AC voltage.

关 键 词：SF_(6) 气体绝缘开关 临界击穿场强 阶段先导发展模型 

分 类 号：TM213[一般工业技术—材料科学与工程]