低温SF_(6)/CF_(4)混气中绝缘子闪络电压的概率分布  

Probability Distribution of Insulator Flashover Voltage in Low TemperatureSF_(6)/CF_(4) Gas Mixture

作　　者：陈远东 郑宇 孟辉 李儒璋 张海龙 梁建 周文俊[2] CHEN Yuandong;ZHENG Yu;MENG Hui;LI Ruzhang;ZHANG Hailong;LIANG Jian;ZHOU Wenjun(EHU/UHV Branch of Inner Mongolia Eastern Power Limited Liability Company of State Grid,Inner Mongolia Tongliao 028000,China;School of Electrical Engineering and Automation,Wuhan University,Wuhan 430072,China)

机构地区：[1]国网内蒙古东部电力有限公司超特高压分公司,内蒙古通辽028000 [2]武汉大学电气与自动化学院,武汉430072

出　　处：《高压电器》2022年第7期229-236,共8页High Voltage Apparatus

基　　金：国网内蒙古东部电力有限公司科技项目(JS1900697,JS2000630)。

摘　　要：SF_(6)/CF_(4)混合气体主要应用于低温环境下的气体绝缘电气设备中,气固交界面是设备的绝缘薄弱环节,有必要研究低温环境下SF_(6)/CF_(4)混合气体中的绝缘子沿面闪络特性。文中首先分析了SF_(6)/CF_(4)混合气体的基本绝缘和液化特性,据此选择0.7 MPa 50%SF_(6)/50%CF_(4)混合气体进行-50~20℃温度范围内的圆柱形绝缘子沿面闪络试验,同时开展了0.5 MPa SF_(6)气体在-35~20℃温度范围内的对照试验。其次采用威布尔分布分析了沿面闪络电压的概率分布特性。发现SF_(6)/CF_(4)混合气体中的绝缘子沿面闪络电压服从威布尔分布,利用威布尔分布可反映不同累积概率下的闪络电压及其分散性,其特征闪络电压随温度降低呈先下降再上升最后再下降的变化趋势。建议0.7 MPa 50%SF_(6)/50%CF_(4)混合气体的最低使用温度不低于-40℃,该值低于0.5 MPa SF_(6)气体的最低使用温度建议值-35℃,研究结果对SF_(6)/CF_(4)混合气体在低温下的应用具有参考意义。SF_(6)/CF_(4)gas mixture is mainly used in gas insulated switchgear(GIS)in low temperature environment.The gas⁃solid interface belongs to the weak insulation link of the equipment.It is therefore necessary to study the flashover characteristic along the surface of insulator in SF_(6)/CF_(4)gas mixture in low temperature environment.In this paper,the basic insulation and liquefaction characteristics of SF_(6)/CF_(4)gas mixture are analyzed firstly.On this basis,50%SF_(6)/50%CF_(4)gas mixture at 0.7 MPa is selected for the flashover test along the surface of cylindrical in⁃sulator in the temperature range of⁃50~20℃and,at the same time,the control test with SF_(6)gas at 0.5 MPa is per⁃formed in the temperature range of⁃35~20℃.Then,the probability distribution characteristics of surface flash⁃over voltage are analyzed by Weibull distribution.It is found that the flashover voltage along the surface of insulator in SF_(6)/CF_(4)gas mixture follows Weibull distribution.The use of Weibull distribution can reflect the flashover voltage and its dispersion under different cumulative probability,and its characteristic flashover voltage shows the varia⁃tion trend of decrease first,then increase and finally decrease again with the decrease of temperature.It is suggested that the minimum service temperature of 50%SF_(6)/50%CF_(4)gas mixture at 0.7 MPa should not be lower than-40℃,which is lower than-35℃,the suggested minimum service temperature of SF_(6)gas at 0.5 MPa.The research results have reference significance for the application of SF_(6)/CF_(4)gas mixture at low temperature.

关 键 词：SF_(6)/CF_(4) 气体绝缘 气体放电 沿面闪络 概率分布 

分 类 号：TM216[一般工业技术—材料科学与工程]