不均匀淋雨条件下SF6绝缘直流穿墙套管直流电压闪络特性  

DC Voltage Flashover Characteristics of SF Insulated DC Wall Bushing Under Uneven Rain Conditions

作　　者：谢雄杰 罗晓庆 胡伟 叶奇明 许佐明 黄尧峰 XIE Xiongjie;LUO Xiaoqing;HU Wei;YE Qiming;XU Zuoming;HUANG Yaofeng(State Key Laboratory of Power Grid Environmental Protection,China Electric Power Research Institute,Wuhan 430074,China;Beijing Hua Tian Mechanical-Electrical Institute Co.,Ltd.,Beijing 100143,China)

机构地区：[1]中国电力科学研究院有限公司电网环境保护国家重点实验室,武汉430074 [2]北京华天机电研究所有限公司,北京100143

出　　处：《高电压技术》2021年第6期2084-2090,共7页High Voltage Engineering

基　　金：国家电网有限公司科技项目(特高压直流穿墙套管内外绝缘配合优化配置及长期绝缘性能研究)(GY71-18-022)。

摘　　要：不均匀淋雨是直流穿墙套管在雨天由于阀厅墙壁遮挡而产生的一种特殊运行工况,不均匀淋雨会显著降低直流穿墙套管的外绝缘强度,不均匀淋雨导致的外绝缘闪络是影响直流穿墙套管安全运行的主要原因之一。为此,利用±100 kV、±400 kV SF6绝缘直流穿墙套管产品开展了不均匀淋雨直流电压闪络试验,记录了试品的不均匀淋雨闪络电压值,监测了试品从施加电压到闪络过程中的电弧发展、电晕和泄漏电流变化情况,获得了典型SF6绝缘直流穿墙套管在不同外绝缘干湿区比例和雨水电导率条件下的直流电压闪络特性。研究结果表明:当雨水电导率为1 500μS/cm时,±400 kV SF6绝缘直流穿墙套管在外绝缘干区和湿区长度比为1:4时直流闪络电压出现最低值623 kV,较全湿条件下的直流闪络电压低9.0%;干区和湿区长度比保持1:4时,±400 kV SF6绝缘直流穿墙套管在雨水电导率为1 500μS/cm条件下的直流闪络电压较雨水电导率为200μS/cm时的直流闪络电压低16.2%。研究结果可为直流穿墙套管外绝缘设计提供参考,也可为直流输电工程中穿墙套管不均匀淋雨闪络问题的预防提供理论支撑。Uneven rain is a special operating condition of DC wall bushing due to the sheltering effect of the wall of valve hall,and can significantly reduce the external insulation strength of DC wall bushing;moreover, external insulation flashover caused by uneven rain is one of the main reasons influencing the safety operation of wall bushing. Consequently, we experimentally investigated the DC voltage flashover characteristics of typical SF6 insulated DC wall bushing under different external insulation wet area ratio and rain conductivity. All the tests were carried out on ±100 kV and ±400 kV SF6 insulated DC wall bushing products. By adjusting the rainwater conductivity, DC test voltages were applied to the wet bushing until flashover,and the development of arc, corona and leakage current was monitored in the flashover process. The research results show that, when the rain conductivity is 1 500 μS/cm, the lowest DC flashover voltage of ±400 kV SF6 insulated DC wall bushing occurs at 623 kV under the condition when the length ratio of dry and wet area is 1:4, which is 9.0% lower than the flashover voltage under total wet condition. When the length ratio of dry and wet area of ±400 kV DC wall bushing is 1:4, the DC flashover voltage under the rain conductivity of 1 500 μS/cm is 16.2% lower than that under the rain conductivity of 200 μS/cm. The results can provide a reference for the insulation structure design of DC wall bushing, and also provide a theoretical support for avoiding uneven rain flashover of DC wall bushing in DC power transmission projects.

关 键 词：直流 穿墙套管 SF6气体绝缘 不均匀淋雨 闪络 雨水电导率 

分 类 号：TM216.52[一般工业技术—材料科学与工程]