极寒环境下户外充油电缆终端故障机理研究  

Research on Failure Mechanism of Outdoor Oil-filled Cable Terminal Under Extremely Cold Conditions

作　　者：宋鹏先[1] 贺春 李隆基[1] 孟庆霖[2] 郭新[2] 杜伯学 李奇 SONG Pengxian;HE Chun;LI Longji;MENG Qinglin;GUO Xin;DU Boxue;LI Qi(Tianjin Electric Power Research Institute of State Grid Tianjin Electric Power Company,Tianjin 300384,China;State Grid Tianjin Electric Power Company,Tianjin 300000,China;School of Electrical and Information Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]国网天津市电力公司电力科学研究院,天津300384 [2]国网天津市电力公司,天津300000 [3]天津大学电气自动化与信息工程学院,天津300072

出　　处：《绝缘材料》2022年第6期71-77,共7页Insulating Materials

基　　金：国网天津市电力公司运维项目(电科-日常21-02-01)。

摘　　要：户外充油电缆终端是高压输变线路中的关键附件,在寒冷天气下,国内连续发生多起高压电缆终端故障,严重影响电网运行安全。为此,本文设计了充油电缆终端主绝缘-应力锥界面绝缘等效试验装置,分别测试了10℃及-30℃下硅橡胶/XLPE界面涂覆硅油对局部放电活动的影响,并基于微观观测及电场仿真手段对故障机理进行探究。结果表明:在10℃下,界面涂覆硅油可以有效改善电缆终端界面相容性,增强界面绝缘强度,无缺陷及存在划痕缺陷时,涂覆硅油后界面局部放电起始电压相较于未涂覆硅油时分别提高约17.2%和200%;然而,在-30℃下,硅油存在凝固收缩效应,导致气隙的产生或固有缺陷再次暴露,局部放电起始电压显著降低,甚至略低于未涂覆硅油状态。电场仿真结果表明极寒环境下最大场强畸变值达6.26 kV/mm,已超过空气的电气强度,极易引发放电击穿。Outdoor oil-filled cable terminals are key accessories in high-voltage transmission and transformation lines.However,high-voltage cable terminal failures have occurred continuously under cold weather in China,which seriously affects the safety of power grid operation.For this reason,an equivalent experimental device for the cable main insulation-stress cone interface insulation of the oil-filled cable terminal was designed,and the effect of the silicone rubber/XLPE interface coating silicone oil on the partial discharge activity under 10℃and-30℃was tested.Moreover,the failure mechanism was studied according to microscopic observations and electric field simulation.The results show that under 10℃,coating silicone oil on the interface can effectively improve the compatibility and insulation strength of the cable terminal interface.When there is no scratch,the partial discharge initial voltage of the interface coating with silicone oil is about 17.2%and 200%higher than that without coating silicone oil.However,under-30℃,silicone oil has a solidification shrinkage effect,resulting in the generation of air gap or the re-exposure of inherent blemish,and the partial discharge initial voltage decreases significantly,which is even slightly lower than that without coating silicone oil.The electric field simulation results show that the maximum field strength distortion value under very cold environment is 6.26 kV/mm,which is higher than the electric strength of air,and it is easy to cause discharge breakdown.

关 键 词：充油电缆终端 极寒天气 硅油凝固 电场畸变 

分 类 号：TM247[一般工业技术—材料科学与工程]