界面气隙缺陷及受潮对±320kV直流电缆中间接头电场分布的影响  

Influence of interfacial air gap defects and moisture on electric field distribution in intermediate joint of ±320 kV DC cables

作　　者：奚锐 张亚 程明亮 詹陶 曹亮 何高辉 桂银刚 唐超[1] XI Rui;ZHANG Ya;CHENG Mingliang;ZHAN Tao;CAO Liang;HE Gaohui;GUI Yingang;TANG Chao(College of Engineering and Technology,Southwest University,Chongqing 400715,China;Chongqing Taishan Cable Co.,Ltd.,Chongqing 401125,China)

机构地区：[1]西南大学工程技术学院,重庆400715 [2]重庆泰山电缆有限公司,重庆401125

出　　处：《绝缘材料》2025年第1期97-108,共12页Insulating Materials

基　　金：重庆市自然科学基金资助项目(sl202100000470)。

摘　　要：为分析直流电缆中间接头多层复合介质绝缘界面气隙缺陷及受潮对其电场分布的影响,本文在建立±320kV直流电缆中间接头仿真模型的基础上,基于有限元法计算了电缆中间接头在多层复合介质界面区域存在气隙、水膜缺陷时的电场分布,分析了空载与负载两种运行条件下缺陷对中间接头电场分布的影响,并进一步讨论了缺陷在交/直流电场作用下电缆接头电场分布的差异。结果表明:在直流电场作用下,气隙、水膜缺陷均会导致直流电缆中间接头在复合介质界面处的电场发生显著的畸变,气隙在空载、负载时的场强畸变倍数分别为9.6倍、1.7倍,水膜缺陷内场强在两种运行条件下均急剧缩减为原来的99.9%以上;电缆中间接头存在气隙缺陷空载时的场强畸变倍数要大于负载时的场强畸变倍数,接头内外存在的温度梯度起到了一定的均匀电场作用;界面受潮在负载运行时的温度场促进了接头内空间电荷积累,从而引起水膜缺陷处的场强畸变倍数较空载时的场强畸变倍数更大;相比于交流电缆,直流电缆中间接头存在缺陷导致的场强畸变倍数更大。To investigate the impact of interface air gap and moisture defects on the multilayer composite dielectric insulation interface of±320 kV DC cable intermediate joints on their electric field distribution mechanism,a simulation model of±320 kV DC cable intermediate joint was built,and the electric field distribution of the cable joint with air gap and moisture defects on the multilayer composite dielectric interface region was calculated using the finite element method.The effect of these defects on the electric field distribution of the cable joint were analyzed at no load and load conditions,and their differences under AC/DC electric fields were discussed.The results show that there is significant electric field distortion at the composite dielectric interface of the DC cable joint due to air gap and moisture defects under the action of DC electric field.The multiple of electric field distortion of air gap defects is 9.6 times at no load and 1.7 times at load condition.The electric field strength in the water film defects decrease over 99.9%at both operating conditions.Interestingly,the electric field distortion induced by air gap defects in cable joints at no load is larger than that at load condition,and the temperature differentials across the joint play a role in field homogenization.However,the temperature differentials across the joint induced by moisture at load promote the accumulation of space charge in the joint,which leading to the multiple of electric field distortion at moisture defect bigger than than at no load.Notably,the multiple of electric field distortion resulting from defects in DC cable intermediate joint is bigger than that of AC cables.

关 键 词：电缆中间接头 直流 界面缺陷 电场分布 

分 类 号：TM855[电气工程—高电压与绝缘技术]