电场作用下分子链的取向行为对水树老化电缆修复效果的影响
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摘要
为提高交联聚乙烯电缆注入式绝缘修复的速率和效果,阐明了利用电场作用提高水树老化电缆修复效果的方法及机理。首先通过加速水树老化实验培养水树老化电缆样本,之后将水树老化电缆样本分为4组,对4组样本分别在不施加电压、施加直流正极性电压、施加直流负极性电压、施加工频电压条件下进行注入式绝缘修复,修复期间定期测量4组样本的介质损耗因数及泄漏电流。修复结束后对样品进行显微镜切片以及扫描电镜(SEM)观察,并对比分析了不同电场修复条件下水树修复电缆样本的微观结构和整体绝缘性能。实验结果表明,缆芯施加电压时电缆样本绝缘恢复速度高于未施加电压样本。并且当缆芯施加直流正极性电压时样本绝缘恢复速度在4组修复样本中最快。此外,SEM观察结果表明,施加直流正极性电压修复样本水树区域修复液与水反应生成物分布最为均匀,填充效果在4组样本中最优。结果表明,注入式修复时施加电压可使交联聚乙烯非晶区的分子链、链段发生取向(定向排列),并且水树通道打开,促进了修复液在绝缘层内的渗透,导致电缆绝缘恢复速度提升。而当电缆施加直流正极性电压时,由于水树区域积累的电荷加强了水树前端的电场,进一步提高了绝缘恢复速度。
To improve the rate and the effect of injected rejuvenation of XLPE cables, we put forward a method and theory for improving the rejuvenation effect and rate of water-tree aged power cables by using electric field. First, cable samples were subjected to an accelerated water tree aging experiment to obtain the water tree aged cable samples. Then, the aged samples were divided into 4 groups and they were rejuvenated without electric field, or with positive DC voltage, negative DC voltage, and power frequency voltage, respectively. During the rejuvenation, the dielectric loss factor(tanδ) and leakage current of the 4 groups of samples were tested regularly. After the rejuvenation, the 4 groups of samples were cut into pieces for microscope observation and scanning electron microscope(SEM). Meanwhile, for the rejuvenated cable samples which were applied to different electric fields, the microstructure and electrical performance of them were compared and analyzed. The experimental results show that, compared with the samples which are rejuvenated without electric field, the recovery speed of insulation of the samples rejuvenated with electric field is higher, and the recovery speed of the insulation of the samples rejuvenated with positive DC voltage is the highest. The SEM observation results show that the samples rejuvenated with positive DC voltage, the reaction products between rejuvenation liquid and water is the most uniformly distributed and the filling effect is the best in the four groups. The results indicate that when cables are rejuvenated with electric field, the molecular chain and chain segment of amorphous area of XLPE can be oriented(in directed arrangement) under the effect of electric field. In addition, the water-tree channel will be opened, which can promote the infiltration of the rejuvenation liquid in insulating layer, leading to the promotion of the rejuvenation effect. When the samples are rejuvenated under positive DC voltage, the charge around the water tree area can strengthen the electric field in front of water tree area, which can further improve the recovery speed of the insulation.
To improve the rate and the effect of injected rejuvenation of XLPE cables, we put forward a method and theory for improving the rejuvenation effect and rate of water-tree aged power cables by using electric field. First, cable samples were subjected to an accelerated water tree aging experiment to obtain the water tree aged cable samples. Then, the aged samples were divided into 4 groups and they were rejuvenated without electric field, or with positive DC voltage, negative DC voltage, and power frequency voltage, respectively. During the rejuvenation, the dielectric loss factor(tanδ) and leakage current of the 4 groups of samples were tested regularly. After the rejuvenation, the 4 groups of samples were cut into pieces for microscope observation and scanning electron microscope(SEM). Meanwhile, for the rejuvenated cable samples which were applied to different electric fields, the microstructure and electrical performance of them were compared and analyzed. The experimental results show that, compared with the samples which are rejuvenated without electric field, the recovery speed of insulation of the samples rejuvenated with electric field is higher, and the recovery speed of the insulation of the samples rejuvenated with positive DC voltage is the highest. The SEM observation results show that the samples rejuvenated with positive DC voltage, the reaction products between rejuvenation liquid and water is the most uniformly distributed and the filling effect is the best in the four groups. The results indicate that when cables are rejuvenated with electric field, the molecular chain and chain segment of amorphous area of XLPE can be oriented(in directed arrangement) under the effect of electric field. In addition, the water-tree channel will be opened, which can promote the infiltration of the rejuvenation liquid in insulating layer, leading to the promotion of the rejuvenation effect. When the samples are rejuvenated under positive DC voltage, the charge around the water tree area can strengthen the electric field in front of water tree area, which can further improve the recovery speed of the insulation.
引文
[1]吴明祥,欧阳本红,李文杰.交联电缆常见故障及原因分析[J].中国电力,2013,46(5):66-70.WU Mingxiang,OUYANG Benhong,LI Wenjie.XLPE cable common failures and cause analysis[J].Electric Power,2013,46(5):66-70.
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[8]余翔,韩铭,杨小震.分子动力学模拟研究线型聚乙烯链在强电场中的取向行为[J].高等学校化学学报,2011,32(1):180-184.YU Xiang,HAN Ming,YANG Xiaozhen.Molecular dynamics simulation study on the reorientation behavior of linear polyethylene under high electric field[J].Chemical Joumal of Chinese Universities,2011,32(1):180-184.
[9]何曼君,张红东,陈维孝,等.高分子物理[M].3版.上海:复旦大学出版社,2006:136-139.HE Manjun,ZHANG Hongdong,CHEN Weixiao,et al.Polymer physics[M].3rd ed.Shanghai,China:Fudan University Press,2006:136-139.
[10]THUE W A.电力电缆工程[M].孙建生,徐晓峰,译.3版.北京:机械工业出版社,2014:276.THUE W A.Electrical power cable engineering[M].SUN Jiansheng,XU Xiaofeng,translated.3rd ed.Beijing,China:China Machine Press,2014:276.
[11]焦立平.用X射线正交透射法测定碳纤维原丝的取向度[J].化工科技,2005,13(2):46-48.JIAO Liping.Using X-ray orthogonal transmission method for determining the orientation degree of the carbon fiber strand[J].Science&Technology in Chemical Industry,2005,13(2):46-48.
[12]杨滴,周凯,陶文彪,等.预修复对交联聚乙烯电缆中水树生长的抑制作用[J].高电压技术,2015,41(8):2732-2740.YANG Di,ZHOU Kai,TAO Wenbiao,et al.Inhibition effect of prior rejuvenation on water tree propagation in XLPE cables[J].High Voltage Engineering,2015,41(8):2732-2740.
[13]BERTINI G J.Advances in chemical rejuvenation of submarine cables[J].Journal of the Japanese Society of Revegetation Technology,2007,32(Supplement 1):475-479.
[14]周凯,陶霰韬,赵威,等.在水树通道内生成纳米TiO2的电缆修复方法及其绝缘增强机制研究[J].中国电机工程学报,2013,33(7):202-210.ZHOU Kai,TAO Xiantao,ZHAO Wei,et al.A cable rejuvenation method based on formation of nano-TiO2 inside water tree and its insulation enhancement mechanism[J].Proceedings of the CSEE,2013,33(7):202-210.
[15]周凯,熊庆,赵威,等.硅氧化烷注入后水树老化交联聚乙烯电缆电气特性和微观结构[J].高电压技术,2015,41(8):2657-2664.ZHOU Kai,XIONG Qing,ZHAO Wei,et al.Electrical properties and micro-structures of water-tree aged XLPE cables after siloxane fluid injection[J].High Voltage Engineering,2015,41(8):2657-2664.
[16]BERTINI G J.New developments in solid dielectric life extension technology[C]∥IEEE International Symposium on Electrical Insulation.Indianapolis,IN,USA:IEEE,2004:527-531.
[17]PELISSOU S.Underground medium-voltage cable rejuvenation-part 1:laboratory tests on cables[J].IEEE Transactions on Power Delivery,2011,26(4):2324-2332.
[18]江日洪.交联聚乙烯电力电缆线路[M].2版.北京:中国电力出版社,2009:123-125.JIANG Rihong.XLPE cable line[M].2nd ed.Beijing,China:China Electric Power Press,2009:123-125.
[19]HVIDSTEN S,IIDSTAD E,SLETBAK J.Understanding water treeing mechanisms in the development of diagnostic test methods[J].IEEE Transactions on Dielectrics and Electrical Insulation,1998,5(5):754-760.
[20]BERTINI G J,VINCENT G A.Rejuvenation reformulated[C]∥IEEEInsulated Conductor Committee,Sub A.Reno,USA:IEEE,2007:1-4.
[2]ROSS R,SMIT J J.Composition and growth of water trees in XLPE[J].IEEE Transactions on Electrical Insulation,1992,27(6):519-531.
[3]BERTINI G J,KEITGES N E.Silicone injection better with pressure[C]∥IEEE Power Energy Society Insulated Conductor Committee.Reno,USA:IEEE,2009:1-7.
[4]朱晓辉.修复水树老化XLPE电缆的修复液注入技术[J].高电压技术,2004,30(增刊1):16-18.ZHU Xiaohui.The repair liquid injection technology of XLPE cable for repairing water tree[J].High Voltage Engineering,2004,30(Supplement 1):16-17.
[5]BERTINI G J,VINCENT G.Cable rejuvenation mechanisms[C]∥Minutes of IEEE Insulated Conductors Committee(ICC)Sub A.Reno,USA:IEEE,2006:1-8.
[6]CHATTERTON W J,DIONNE J.Chemical treatment of URD cables[C]∥Electrical Insulation Conference.Montreal,Canada:IEEE,2009:500-503.
[7]STAGI W R.Cable injection technology[C]∥IEEE Latin America Conference.Caracas,Venezuela:IEEE,2006:1-4.
[8]余翔,韩铭,杨小震.分子动力学模拟研究线型聚乙烯链在强电场中的取向行为[J].高等学校化学学报,2011,32(1):180-184.YU Xiang,HAN Ming,YANG Xiaozhen.Molecular dynamics simulation study on the reorientation behavior of linear polyethylene under high electric field[J].Chemical Joumal of Chinese Universities,2011,32(1):180-184.
[9]何曼君,张红东,陈维孝,等.高分子物理[M].3版.上海:复旦大学出版社,2006:136-139.HE Manjun,ZHANG Hongdong,CHEN Weixiao,et al.Polymer physics[M].3rd ed.Shanghai,China:Fudan University Press,2006:136-139.
[10]THUE W A.电力电缆工程[M].孙建生,徐晓峰,译.3版.北京:机械工业出版社,2014:276.THUE W A.Electrical power cable engineering[M].SUN Jiansheng,XU Xiaofeng,translated.3rd ed.Beijing,China:China Machine Press,2014:276.
[11]焦立平.用X射线正交透射法测定碳纤维原丝的取向度[J].化工科技,2005,13(2):46-48.JIAO Liping.Using X-ray orthogonal transmission method for determining the orientation degree of the carbon fiber strand[J].Science&Technology in Chemical Industry,2005,13(2):46-48.
[12]杨滴,周凯,陶文彪,等.预修复对交联聚乙烯电缆中水树生长的抑制作用[J].高电压技术,2015,41(8):2732-2740.YANG Di,ZHOU Kai,TAO Wenbiao,et al.Inhibition effect of prior rejuvenation on water tree propagation in XLPE cables[J].High Voltage Engineering,2015,41(8):2732-2740.
[13]BERTINI G J.Advances in chemical rejuvenation of submarine cables[J].Journal of the Japanese Society of Revegetation Technology,2007,32(Supplement 1):475-479.
[14]周凯,陶霰韬,赵威,等.在水树通道内生成纳米TiO2的电缆修复方法及其绝缘增强机制研究[J].中国电机工程学报,2013,33(7):202-210.ZHOU Kai,TAO Xiantao,ZHAO Wei,et al.A cable rejuvenation method based on formation of nano-TiO2 inside water tree and its insulation enhancement mechanism[J].Proceedings of the CSEE,2013,33(7):202-210.
[15]周凯,熊庆,赵威,等.硅氧化烷注入后水树老化交联聚乙烯电缆电气特性和微观结构[J].高电压技术,2015,41(8):2657-2664.ZHOU Kai,XIONG Qing,ZHAO Wei,et al.Electrical properties and micro-structures of water-tree aged XLPE cables after siloxane fluid injection[J].High Voltage Engineering,2015,41(8):2657-2664.
[16]BERTINI G J.New developments in solid dielectric life extension technology[C]∥IEEE International Symposium on Electrical Insulation.Indianapolis,IN,USA:IEEE,2004:527-531.
[17]PELISSOU S.Underground medium-voltage cable rejuvenation-part 1:laboratory tests on cables[J].IEEE Transactions on Power Delivery,2011,26(4):2324-2332.
[18]江日洪.交联聚乙烯电力电缆线路[M].2版.北京:中国电力出版社,2009:123-125.JIANG Rihong.XLPE cable line[M].2nd ed.Beijing,China:China Electric Power Press,2009:123-125.
[19]HVIDSTEN S,IIDSTAD E,SLETBAK J.Understanding water treeing mechanisms in the development of diagnostic test methods[J].IEEE Transactions on Dielectrics and Electrical Insulation,1998,5(5):754-760.
[20]BERTINI G J,VINCENT G A.Rejuvenation reformulated[C]∥IEEEInsulated Conductor Committee,Sub A.Reno,USA:IEEE,2007:1-4.
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