温度对GIS内部固体绝缘缺陷间歇性放电特性影响研究

The impact of temperature on intermittent discharge characteristics of solid insulation defects inside GIS

针对现场气体绝缘组合电器(gas insulated substation,GIS)局部放电绝缘缺陷漏报、误报情况频发的问题,文中根据GIS实际运行温度范围对GIS内部常见固体绝缘缺陷开展不同温度下间歇性放电特性试验研究,搭建GIS电-热耦合间歇性放电模拟试验平台,采用脉冲电流法、特高频(ultra high frequency,UHF)法、超声波法和气体特征组分检测法获取不同温度下固体绝缘缺陷间歇性放电特征数据并进行分析。研究发现:UHF法和脉冲电流法在不同温度下均能有效检测到试验缺陷间歇性放电UHF信号,超声波法和气体特征组分检测法无法有效采集到有效放电数据;固体绝缘表面金属污秽缺陷和内部气隙缺陷间歇性放电电压与温度呈负相关,污秽缺陷间歇性放电电压呈较为明显的线性下降趋势,气隙缺陷间歇性放电电压呈先大幅下降后较平缓线性下降趋势;污秽缺陷间歇性放电的平均放电量和UHF信号幅值与温度的升高呈正相关;污秽缺陷放电间歇性在不同温度下随放电时间的增加会增强,而气隙缺陷放电时间间隔在26℃、40℃、50℃下能由秒级发展为毫秒级,存在演变成击穿放电的风险。文中研究成果进一步丰富了GIS间歇性放电理论体系,有助于提升现场GIS间歇性放电的有效诊断率。

Given the frequent missing and false alarms of partial discharge insulation defects in on-site gas insulated substation(GIS),intermittent discharge characteristics tests are conducted in this article to study the discharge characteristics of common solid insulation defects inside GIS at different temperatures in the actual operating temperature range of GIS.In this paper,the platform of GIS electric thermal coupling intermittent discharge simulation test is built with the pulse current method,ultrahigh frequency(UHF) method,ultrasonic method and gas characteristic component detection method used in combination to obtain and analyze the intermittent discharge characteristic data of solid insulation defects at different temperatures.It is found out that both UHF detection method and pulse current detection method can effectively detect the intermittent discharge UHF signals of test defects at different temperatures,while ultrasonic and gas characteristic component detection methods are not applicable to effectively collect effective discharge data.The intermittent discharge voltage of metal pollution defects on the surface of solid insulation and internal air gap defects shows a negative correlation with temperature.The intermittent discharge voltage of pollution defects shows a significant trend of linear decrease,while the intermittent discharge voltage of air gap defects shows a significant decrease first and then a trend of slow-paced linear decrease.The average discharge capacity and UHF signal amplitude of intermittent discharge of pollution defects exhibit a positive correlation with the increase of temperature.The intermittency of pollution defect discharge increases with the extension of discharge time at different temperatures,while the interval of gap defect discharge can change from second level to microsecond level at 26 ℃,40 ℃ and 50 ℃,posing a risk of breakdown discharge.The research results obtained in this article further enrich the theoretical system of GIS intermittent discharge and improve the effective diagnosis rate of on-site GIS intermittent discharge.