SF_(6)混合气体放电的极性反转特性研究  

Study on Polarity Reversal Characteristics of SF_(6) Gas Mixture Discharge

作　　者：陈远东 郑宇 CHEN Yuandong;ZHENG Yu(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》2024年第7期114-121,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(SGMDJX00YJJS2000630)。

摘　　要：SF_(6)混合气体可在极寒条件下替代SF_(6)气体用于气体绝缘电气设备,当设备中存在缺陷时会显著降低击穿电压,因此有必要研究缺陷产生的极不均匀电场中SF_(6)混合气体的放电特性。开展了针板电极下SF_(6)/CF_(4)、SF_(6)/N_(2)混合气体的放电试验,并和SF_(6)气体对比,分析其击穿电压随气压增大呈现的驼峰曲线变化规律。发现SF_(6)混合气体的驼峰曲线相比SF_(6)气体会发生右移,且SF_(6)/N_(2)混合气体的右移现象更加明显。进一步对比研究了不同气压下SF_(6)混合气体的击穿与局放特性,发现SF_(6)/CF_(4)、SF_(6)/N_(2)混合气体的击穿电压均随气压升高出现极性反转,即从负极性击穿转化为正极性击穿,极性反转对应的气压即为驼峰曲线峰谷处的气压;同时,局放特性也会随气压升高出现变化,即从正负极性局放共存转化为只存在正极性局放。通过分析SF_(6)混合气体的局放起始电压随气压的变化趋势,发现当高于峰谷气压时,局放起始电压与击穿电压相差较小,这一现象说明SF_(6)混合气体设备在较高气压时也更易出现无晕击穿,与SF_(6)气体设备的运维经验一致。研究结果对于SF_(6)混合气体设备的运维检修和设计具有参考意义。SF_(6) gas mixture can replace SF_(6) gas in gas insulated electrical equipment under extremely cold conditions.In case of defect in the equipment,it will significantly reduce the breakdown voltage.It is therefore necessary to study the discharge characteristics of SF_(6) gas mixture in extremely uneven electric field induced by the defect.The discharge test of SF_(6)/CF_(4) and SF_(6)/N_(2) gas mixture under needle plate electrode is performed and,compared with SF_(6) gas,the variation of hump curve of breakdown voltage with the increase of gas pressure is analyzed.It is found that the hump curve of SF_(6) gas mixture will shift to the right compared with SF_(6) gas,and the right shift of SF_(6)/N_(2) gas mixture is more obvious.The breakdown and partial discharge characteristics of SF_(6) gas mixtures at different pressures are compared and studied further.It is found that the breakdown voltage of SF_(6)/CF_(4) and SF_(6)/N_(2) gas mixtures has polarity reversal with the increase of gas pressure,that is,from negative polarity breakdown to positive polarity breakdown,and the gas pressure corresponding to polarity reversal is the gas pressure at the valley of hump curve.At the same time,the characteristics of partial discharge will also change with the increase of gas pressure,namely,from coexistence of both negative and positive partial discharge to only positive partial discharge.It is found through analyzing the variation trend of initial partial discharge voltage of SF_(6) gas mixture with gas pressure that,in case of exceeding the valley gas pressure,the difference between the initial partial discharge and the breakdown voltage is less,showing that SF_(6) gas mixture equipment is more prone to corona free breakdown at higher gas pressure,which is consistent with the operation and maintenance experience of SF_(6) gas equipment.The research results have reference significance for the operation and maintenance of SF_(6) gas mixture equipment.

关 键 词：SF_(6)混合气体 气体绝缘 气体放电 无晕击穿 驼峰曲线 

分 类 号：TM213[一般工业技术—材料科学与工程]