硅橡胶电树枝的引发与生长过程
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摘要
交联聚乙烯电力电缆的应用日渐广泛,但电缆附件的电树枝击穿故障时有发生,电缆附件材料硅橡胶的电树枝引发和生长过程尚缺乏深入研究。为此,通过材料的测试分析与计算等手段,定量描述了硅橡胶材料微观结构,测试、分析了电树枝引发期的电树枝通道特征和局部放电特性。研究结果表明:硅橡胶中同时存在主链上的化学交联以及通过氢键吸附形成的物理交联;在交流场强下物理交联破坏使得材料中的微裂纹逐渐扩大,最终导致电树枝引发;硅橡胶电树枝通道呈现良好的绝缘特性,电树枝生长主要依靠局部放电下气体受热膨胀或电磁力产生的撕裂作用;增强机械性能尤其是撕裂特性可以提高材料的抗电树枝老化性能。研究硅橡胶材料的电树枝引发和生长过程为其在电缆附件中的合理使用提供了理论依据。
Cross-linked polyethylene power cables are more and more widely used, but they still have electrical tree break-down happened in cable accessories occasionally, while the mechanism of electrical treeing's initiation and propagation needs further research. Therefore, through material and calculative analyses, we described the microscopic structure of silicone rubber quantitatively, and obtained the channel characteristics and partial discharge characteristics during the initiation stage of electrical treeing. It is shown that the microscopic structure of silicone rubber includes a large number of physical crosslinking comprising the crosslinking in silicone rubber together with chemical crosslinking; The breakdown of physical crosslinking structure makes microscopic crack zones become larger, which further causes the electrical tree initiation. Meanwhile, channels of electrical trees have good insulation properties, and the trees' growth depends on the tearing effect of gas heat expansion or electromagnetic force under strong partial discharge mainly. Improving the mechanical properties, especially improving the tear characteristics, can enhance the silicone rubber's ability against electrical trees. The research on the initiation and propagation of electrical trees in silicon rubber provides theoretical basis for the proper application of silicone rubber in cable accessories.
Cross-linked polyethylene power cables are more and more widely used, but they still have electrical tree break-down happened in cable accessories occasionally, while the mechanism of electrical treeing's initiation and propagation needs further research. Therefore, through material and calculative analyses, we described the microscopic structure of silicone rubber quantitatively, and obtained the channel characteristics and partial discharge characteristics during the initiation stage of electrical treeing. It is shown that the microscopic structure of silicone rubber includes a large number of physical crosslinking comprising the crosslinking in silicone rubber together with chemical crosslinking; The breakdown of physical crosslinking structure makes microscopic crack zones become larger, which further causes the electrical tree initiation. Meanwhile, channels of electrical trees have good insulation properties, and the trees' growth depends on the tearing effect of gas heat expansion or electromagnetic force under strong partial discharge mainly. Improving the mechanical properties, especially improving the tear characteristics, can enhance the silicone rubber's ability against electrical trees. The research on the initiation and propagation of electrical trees in silicon rubber provides theoretical basis for the proper application of silicone rubber in cable accessories.
引文
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[13]周远翔,聂琼,姜绿先,等.针尖曲率半径对硅橡胶电树枝老化特性的影响[J].中国电机工程学报,2008,28(34):27-32.ZHOU Yuanxiang,NIE Qiong,JIANG Lüxian,et al.Influence of tip radius of curvature on electrical treeing characteristics in SIR[J].Proceedings of the CSEE,2008,28(34):27-32.
[14]聂琼,周远翔,陈铮铮,等.频率对硅橡胶起树电压及电树枝形态的影响[J].高电压技术,2009,35(1):141-145.NIE Qiong,ZHOU Yuanxiang,CHEN Zhengzheng,et al.Influence of frequency on tree initiation voltage and electrical tree shape in silicone rubber[J].High Voltage Engineering,2009,35(1):141-145.
[15]周远翔,侯非,聂琼,等.温度对硅橡胶电树枝老化特性的影响[J].高电压技术,2012,38(10):2640-2646.ZHOU Yuanxiang,HOU Fei,NIE Qiong,et al.Temperature effects on electrical tree aging characteristics of silicone rubber[J].High Voltage Engineering,2012,38(10):2640-2646.
[16]Zhou Y X,Liu R,Hou F,et al.Effect of silica particles on electrical treeing initiation in silicone rubber[C]∥Annual Report Conference on Electrical Insulation and Dielectric Phenomena.Montreal,Canada:IEEE,2012:609-611.
[17]Zhou Y X,Liu R,Hou F,et al.Morphology of electrical trees in silicon rubber[J].Journal of Electrostatics,2013,71(3):440-448.
[18]周远翔,张旭,刘睿,等.硅橡胶电树枝通道微观形貌研究[J].高电压技术,2014,40(1):9-15.ZHOU Yuanxiang,ZHANG Xu,LIU Rui,et al.Study on micro-morphology of electrical trees in silicon rubber[J].High Voltage Engineering,2014,40(1):9-15.
[19]张旭.硅橡胶电树枝老化局部放特性及放电微观形貌研究[D].北京:清华大学,2013:27-41.ZHANG Xu.Study on partial discharge characteristics and mi-cro-morphology of electrical trees in silicone rubber[D].Beijing,China:Tsinghua University,2013:27-41.
[20]黄文润.液体硅橡胶[M].成都:四川科学技术出版社,2009:244-252.HUANG Wenrun.Liquid silicone rubber[M].Chengdu,China:Sichuan Science and Technology Press,2009:244-252.
[21]Barry A J.Viscometric Investigation of dimethylsiloxane polymers[J].Journal of Applied Physics,1946,17(12):1020-1024.
[22]Flory P J,Rehner J.Statistical mechanics of cross-linked polymer networks,Ⅰ:rubberlike elasticity[J].The Journal of Chemical Physics,1943,11(11):512-520.
[23]Pitsa D,Vardakis G E,Danikas M G.Effect of nanoparticles loading on electrical tree propagation in polymer nanocomposites[C]∥Proceedings of 2011 International Conference on Electrical Insulating Materials(ISEIM).Kyoto,Japan:IEEE,2011:9-11.
[24]陈向荣,徐阳,刘英,等.交联聚乙烯电缆绝缘材料中电树枝的导电特性研究[J].物理学报,2012,61(8):416-425.CHEN Xiangrong,XU Yang,LIU Ying,et al.Study on conducting characteristics of electrical trees in cross-linked polyethylene cable insulation[J].Acta Physica Sinica,2012,61(8):416-425.
[2]Danikas M,Tanaka T.Nanocomposites:a review of electrical treeing and breakdown[J].IEEE Electrical Insulation Magazine,2009,25(4):19-25.
[3]Ieda M,Nawata M.A consideration of treeing breakdown in polymers[C]∥Annual Report Conference Electric Insulation and Dielectric Phenomenon.Tokyo,Japan:IEEE,1972:143-150.
[4]Densley R J.An investigation into the growth of electrical trees in XLPE cable insulation[J].IEEE Transactions on Electrical Insulation,1979,14(3):148-158.
[5]Ishibashi A,Kawai T,Nakagawa S,et al.A study of treeing phenomena in the development of insulation for 500 k V XLPE cable[J].IEEE Transactions on Dielectrics and Electrical Insulation,1998,5(5):695-706.
[6]Varlow B R,Auckland D W.Mechanical aspects of electrical treeing in solid insulation[J].IEEE Electrical Insulation Magazine,1996,12(2):21-26.
[7]Hibma T,Zeller H R.Direct measurement of space-charge injection from a needle electrode into dielectrics[J].Journal of Applied Physics,1986,59(3):1614-1620.
[8]Laurent C,Massines F,Mayoux C.Optical emission due to space charge effects in electrically stressed polymers[J].IEEE Transactions on Dielectrics and Electrical Insulation,1997,4(5):585-603.
[9]Tanaka T,Greenwood A.Effects of charge injection and extraction on tree initiation in polyethylene[J].IEEE Transactions on Power Apparatus and Systems,1978,97(5):1749-1759.
[10]吴炯,陈善同.35 k V聚乙烯电缆树枝化击穿机理的研究[J].西安交通大学学报,1980,14(4):81-91.WU Jiong,CHEN Shantong.Research on the mechanism of the electrical treeing breakdown in 35 k V PE cable[J].Journal of Xi’an Jiaotong University,1980,14(4):81-91.
[11]陆文雄,屠德民,刘其昶.聚乙烯电树枝扩展过程的研究[J].西安交通大学学报,1984,18(3):95-103.LU Wenxiong,TU Demin,LIU Qichang.Research on the progress proceeding of PE electrical treeing[J].Journal of Xi’an Jiaotong University,1984,18(3):95-103.
[12]Shimizu N,Laurent C.Electrical tree initiation[J].IEEE Transactions on Dielectrics and Electrical Insulation,1998,5(5):651-659.
[13]周远翔,聂琼,姜绿先,等.针尖曲率半径对硅橡胶电树枝老化特性的影响[J].中国电机工程学报,2008,28(34):27-32.ZHOU Yuanxiang,NIE Qiong,JIANG Lüxian,et al.Influence of tip radius of curvature on electrical treeing characteristics in SIR[J].Proceedings of the CSEE,2008,28(34):27-32.
[14]聂琼,周远翔,陈铮铮,等.频率对硅橡胶起树电压及电树枝形态的影响[J].高电压技术,2009,35(1):141-145.NIE Qiong,ZHOU Yuanxiang,CHEN Zhengzheng,et al.Influence of frequency on tree initiation voltage and electrical tree shape in silicone rubber[J].High Voltage Engineering,2009,35(1):141-145.
[15]周远翔,侯非,聂琼,等.温度对硅橡胶电树枝老化特性的影响[J].高电压技术,2012,38(10):2640-2646.ZHOU Yuanxiang,HOU Fei,NIE Qiong,et al.Temperature effects on electrical tree aging characteristics of silicone rubber[J].High Voltage Engineering,2012,38(10):2640-2646.
[16]Zhou Y X,Liu R,Hou F,et al.Effect of silica particles on electrical treeing initiation in silicone rubber[C]∥Annual Report Conference on Electrical Insulation and Dielectric Phenomena.Montreal,Canada:IEEE,2012:609-611.
[17]Zhou Y X,Liu R,Hou F,et al.Morphology of electrical trees in silicon rubber[J].Journal of Electrostatics,2013,71(3):440-448.
[18]周远翔,张旭,刘睿,等.硅橡胶电树枝通道微观形貌研究[J].高电压技术,2014,40(1):9-15.ZHOU Yuanxiang,ZHANG Xu,LIU Rui,et al.Study on micro-morphology of electrical trees in silicon rubber[J].High Voltage Engineering,2014,40(1):9-15.
[19]张旭.硅橡胶电树枝老化局部放特性及放电微观形貌研究[D].北京:清华大学,2013:27-41.ZHANG Xu.Study on partial discharge characteristics and mi-cro-morphology of electrical trees in silicone rubber[D].Beijing,China:Tsinghua University,2013:27-41.
[20]黄文润.液体硅橡胶[M].成都:四川科学技术出版社,2009:244-252.HUANG Wenrun.Liquid silicone rubber[M].Chengdu,China:Sichuan Science and Technology Press,2009:244-252.
[21]Barry A J.Viscometric Investigation of dimethylsiloxane polymers[J].Journal of Applied Physics,1946,17(12):1020-1024.
[22]Flory P J,Rehner J.Statistical mechanics of cross-linked polymer networks,Ⅰ:rubberlike elasticity[J].The Journal of Chemical Physics,1943,11(11):512-520.
[23]Pitsa D,Vardakis G E,Danikas M G.Effect of nanoparticles loading on electrical tree propagation in polymer nanocomposites[C]∥Proceedings of 2011 International Conference on Electrical Insulating Materials(ISEIM).Kyoto,Japan:IEEE,2011:9-11.
[24]陈向荣,徐阳,刘英,等.交联聚乙烯电缆绝缘材料中电树枝的导电特性研究[J].物理学报,2012,61(8):416-425.CHEN Xiangrong,XU Yang,LIU Ying,et al.Study on conducting characteristics of electrical trees in cross-linked polyethylene cable insulation[J].Acta Physica Sinica,2012,61(8):416-425.