热老化对交流配电XLPE电缆改为直流运行后电缆绝缘性能的影响  

Effect of Thermal Aging on the Cable Insulation Properties of AC Distribution XLPE Cables Under DC Operation

作　　者：石逸雯 周国伟 孟繁博 王启隆 茅奕晟 陈向荣 SHI Yiwen;ZHOU Guowei;MENG Fanbo;WANG Qilong;MAO Yisheng;CHEN Xiangrong(Zhejiang Provincial Key Laboratory of Electrical Machine Systems,College of Electrical Engineering,Zhejiang University,Hangzhou 310027,China;State Grid Zhejiang Electric Power Corporation Maintenance Branch,Hangzhou 311121,China;Hangzhou Power Supply Company,State Grid Zhejiang Electric Power Corporation,Hangzhou 310009,China)

机构地区：[1]浙江大学电气工程学院浙江省电机系统智能控制与变流技术重点实验室,杭州310027 [2]国网浙江省电力有限公司检修分公司,杭州311121 [3]国网浙江省电力有限公司杭州供电公司,杭州310009

出　　处：《高电压技术》2021年第11期4104-4112,共9页High Voltage Engineering

基　　金：直流输电技术国家重点实验室(南方电网科学研究院有限责任公司)项目(SKLHVDC-2019-KF-18);宁波市“科技创新2025”重大专项(2018B10019);浙江大学“百人计划”(自然科学A类);国网浙江检修公司油浸式互感器绝缘状态分析诊断技术研究及应用(5211MR20004X)。

摘　　要：为了研究热老化对交流配电交联聚乙烯(cross-linked polyethylene,XLPE)电缆改为直流运行后电缆绝缘性能的影响,先对已运行两年的10 kV交流XLPE电缆样段进行135℃加速热老化试验,随后采用车床和特质刀具将电缆样段沿轴向环切得到薄片试样,通过直流电导率、空间电荷测量、表面电位衰减和直流击穿测试,结合载流子迁移率、活化能和陷阱参数的计算,对老化前后交流配电XLPE电缆的直流绝缘性能进行研究。结果表明:随着老化时间的增加,交流XLPE电缆绝缘试样的直流电导率和载流子迁移率先下降后上升,长期老化后空间电荷积累阈值场强与试样的活化能明显减小,试样的直流电导率随着测量温度的升高而增加,其空间电荷积累阈值场强随着测量温度的升高而减小;随着老化时间的增加,试样中积累的空间电荷由异极性转变为同极性,深陷阱数量与直流击穿场强均呈现先上升后下降的趋势;分析认为短期热老化有利于提高交流配电XLPE电缆改为直流运行后的直流绝缘性能。In order to study the effect of thermal aging on the insulation properties of the AC distribution cross-linked polyethylene(XLPE)cable under DC operation,a sample of 10 kV AC XLPE cable that has been in operation for two years is subjected to an accelerated thermal aging test at 135℃in this paper.Through the DC conductivity,space charge measurement,surface potential decay,and DC breakdown tests,combined with the calculation of carrier mobility,activation energy,and trap parameters,the DC insulation properties of AC distribution XLPE cables before and after aging are studied.The results show that,as the aging time increases,the DC conductivity and carrier mobility of the AC XLPE cable insulation sample decrease first and then rise.After long-term aging,the space charge accumulation electric field threshold and activation energy of the samples decrease significantly.As the test temperature increases,the DC conductivity of the sample increases and the electric field threshold decreases.Meanwhile,the accumulated space charge changes from hetero-charge accumulation to homo-charge accumulation with the increase of aging time.The number of deep traps and the DC breakdown strength both increase first and then decrease.Analyses show that short-term thermal aging is beneficial to improve the DC insulation properties of AC distribution XLPE cables.

关 键 词：热老化 交流配电 交联聚乙烯电缆 直流运行 绝缘性能 

分 类 号：TM247[一般工业技术—材料科学与工程]