摘要
直流输电技术由于其在稳定性与经济性等方面的诸多优点,成为目前电气工程领域内研究的热点。高压直流塑料电缆是直流输电的关键设备之一,相对于油纸绝缘直流电缆,具有体积小、输送容量高和免维护等优势,因此研究和开发塑料绝缘直流电缆对直流输电至关重要。然而在塑料绝缘中,由于空间电荷分布不均匀会造成电缆绝缘内电场畸变影响其绝缘强度以及加速绝缘的老化,因此研制塑料绝缘的关键问题是解决绝缘内空间电荷积聚的问题。
本文采用电声脉冲法研究聚乙烯及其复合介质内空间电荷分布发现:聚乙烯生产工艺的不同,造成了其内部空间电荷分布的差异。以不同厂家生产的低密度聚乙烯作为基础材料,掺杂相同类型与含量的填料,复合介质内空间电荷分布有较大差别。复合介质的结晶行为影响其内部空间电荷分布,但其对空间电荷的影响小于杂质离子浓度等因素的影响。交联聚乙烯内交联副产物含量对其空间电荷分布影响较大;研究还发现电极材料也是影响XLPE及其复合介质内空间电荷分布的重要因素之一。
添加适量的纳米MgO粉末可以有效的改善复合介质内空间电荷分布、击穿特性、电导率和机械性能。利用傅里叶变化红外光谱(FT-IR)与差热分析(DSC)对XLPE与MgO/XLPE纳米复合介质进行研究发现,MgO与XLPE的分子基团之间有相对较强的相互作用。
Direct current transmission technology has been a hot topic in the electrical engineering domain, on account of the considerably numerous advantages of it. The high voltage direct current plastic insulated cable is one of the most important equipments in DC transmission technology. Compared with paper insulated DC cables, there are many excellent characteristics of the HVDC plastic insulated cable, such as, relatively small volume, great transmission capability and maintenance-free. So it is crucial to research and develop HVDC plastic insulated cables. The non-homogenous distribution of space charge in the cable insulation may distort the distribution of electric field which will reduce the dielectric strength and accelerate the deterioration of the insulation. As a result, solving the problem of the space charge accumulation in dielectrics is the indispensable and first step to develop HVDC plastic insulated cables.
The pulsed electro-acoustic method is utilized to investigate the space charge distribution in polyethylene and its composites and some conclusions can be drawn. The differences of production process among different types of polyethylene result in the differences of space charge distribution in them. Although loading with the same kind of filler and the same quantity and the base material is LDPE, LDPE produced by different corporation may also make each composite have different characteristics. The crystallization behavior of composites may also affect the space charge distribution in them. However, this affection is less effective than those of other factors, such as, the concentration of impurities. The cross-linking by-products impose great effect on space charge distribution in XLPE. The research results also show that the material of electrodes is also one of important factors which affect the space charge distribution.
Loading proper quantity of nano-MgO can effectively improve the space charge distribution, the breakdown characteristics, conductivity and mechanical performances of composites. By utilizing FT-IR and DSC to investigate XLPE and MgO/XLPE nanocomposites, it can be inferred that there are some strong interaction between the molecular groups of XLPE and MgO nano-particles from analyzing the experiment results.
引文
[1]苏宏田,齐旭,吴云.我国特高压直流输电市场需求研究.电网技术, 2005,(24):1~5
[2]陈士军.直流输电的优势与前景.水电站设计, 2003,(03):78~79
[3]杨勇.高压直流输电技术发展与应用前景.电力自动化设备, 2001,(09):58~60
[4]刘子玉.电气绝缘结构设计原理.机械工业出版社, 1981
[5] Salah K M. International research and development trends and problems of HVDC cables with polymeric insulation. Electrical Insulation Magazine, IEEE, 1997,13(6):35~47
[6]杨斌. 10kV交联聚乙烯绝缘电力电缆应用,寿命及发展探讨.湖北电力, 1996,:27~30
[7] Hanley T L, Burford R P, Fleming R J. A general review of polymeric insulation for use in HVDC cables. Electrical Insulation Magazine, IEEE, 2003,19(1):13~24
[8] Densley J. New material developments in HVDC. International Council on Large Electric Systems(CIGRE), Paris,France, 2000 : Paper 2-00.
[9] Y.Maekawa, K.Watanabe, S.Maruyama, Y.Murata A H H. Research and development of dc +/- 500kV extruded cables. International Council on Large Electric Systems(CIGRE), Paris, France, 2002:21~203
[10] Fothergill. J.C. Electrical Degradation and Breakdown in Polymers. London, U.K.: Peter Peregrinus Ltd., 1992
[11] Lewis T J. The Role of Electrodes in Conduction and Breakdown Phenomena in Solid Dielectrics. IEEE Transactions on Electrical Insulation, 1984,EI-19(3):210~216
[12] Xinsheng W, Demin T, Tanaka Y, et al. Space charge in XLPE power cable under dc electrical stress and heat treatment. IEEE Transactions on Dielectrics and Electrical Insulation, 1995,2(3):467~474
[13] Fleming R J, Henriksen M, Holboll J T. The influence of electrodes and conditioning on space charge accumulation in XLPE. IEEE Transactions on Dielectrics and Electrical Insulation. 2000,7(4):561~571
[14] McAllister I W, Crichton G C, Pedersen A. Charge accumulation in DC cables: a macroscopic approach. Conference Record of the 1994 IEEE International Symposium on Electrical Insulation. 1994:212~216
[15] Yin Y, Tu D, Du Q. Distribution and effect of space charge on dielectric properties in modified XLPE by chlorinated polyethylene. Proceedings of the 6th International Conference on Properties and Applications of Dielectric Materials, 2000:268~271
[16]方亮,付海金,吕亮.等离子表面处理聚乙烯中空间电荷分布.中国电机工程学报, 2003,(08):151~154
[17] Lau W S, Chen G, Davies A E. Concurrent space charge and current density measurements in additive-free LDPE. 2002 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2002:640~643
[18] Yuji H, Hiroyuki A, Yasuhiro T. Space Charge Formation in LDPE/MgO Nano-composite Thin Film under Ultra-high DC Electric Stress. 8th International Conference on Properties and applications of Dielectric Materials. 2006:159~162
[19] Yi Y, Jiong C, Jingning Y. Effect of space charge in nanocomposite of LDPE/TiO2. Proceedings of the 7th International Conference on Properties and Applications of Dielectric Materials. 2003:913~9163
[20] Tanaka T, Kisanuki O, Sakata M, et al. Characteristics of space charge formed in a laminated LDPE/EVA dielectric under DC stress. Conference Record of the 1996 IEEE International Symposium on Electrical Insulation, 1996:184~187
[21] Zhang C, Mizutani T, Kaneko K. Space charge and conduction in LDPE-polypropylene copolymer blends. 2001Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2001:28~31
[22] Cherifi A, Toureille A, Reboul J P. Influence of barium titanate (BaTiO3) additive on space charge formation in polyethylene. 1993 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 1993:140~145
[23]屠德民.高压直流电力电缆的发展概况.电气电子教学学报, 2001,(02):5~12
[24] Uozumi T, Hirotsu K. Japanese Patent JP11224544. Sumitomo Electric Ind. Ltd., 1999,
[25]张冶文,夏钟福,李英.固体电介质中空间电荷分布与极化分布的测量方法及其比较.电工技术学报, 1999,(03):39~44
[26]郑飞虎,张冶文,吴长顺.用于固体介质中空间电荷的压电压力波法与电声脉冲法.物理学报, 2003,(05):1137~1142
[27]高田达雄.电声脉冲法测量空间电荷的原理与方法.西安交通大学出版社, 1994
[28] Vazquez A, Chen G, Davies A E. Space Charge Measurement Using Pulsed Electroacoustic Technique and Signal Recovery. Journal of the European Ceramic Society, 1999(19):1219~1222
[29]杜宏伟,孔瑛, Ying Z.聚酰亚胺/TiO2有机-无机纳米复合膜材料的合成与表征.高分子材料科学与工程, 2004,(01):83~86
[30]李德泉,张树平.纳米聚合物复合材料开发与技术.甘肃科学学报, 2002,14(2):61~65
[31]胡显奎,林少全,刘振兴.聚合物基无机纳米粒子复合材料的制备技术及应用展望.材料导报, 2000,14(10):62~63
[32]李振中,李东红,温变英.无机纳米粒子填充改性聚合物的研究进展.塑料, 2001,30(1):44~48
[33] G.C.Montanari L S. Aging Phenomenology and Modeling. IEEE Transactions on Electric Insulation, 1993,28(5):755~776
[34] Takada T, Hayase Y, Tanaka Y. Space charge trapping in electrical potential well caused by permanent and induced dipoles for LDPE/MgO nanocomposite. IEEE Transactions on Dielectrics and Electrical Insulation, 2008,15(1):152~160
[35] F.Boufayed, S.Leroy, G.Teyssedre, C.Laurent, P.Segur, L.A.Dissado G C M. Models of bipolar charge transport in Polyethylene. J.Applied Phys., 2006,100:104105~104115
[36] Montanari G C. Extration of information from space charge measurements and correlation with insulation ageing. Proc. IEEE CSC, France, 2001, 2001:178~184
[37]甄建.我国XLPE电缆料及基础树脂的发展概况.合成树脂及塑料, 2003,(06)
[38] Y.L.Chong, G.Chen Y F F H. The Effect of Degassing on Morphology and Space Charge. 2004 International Conference on Solid Dielectrics, Toulouse,France, 2004
[39] G.Chen, T.Y.G.Tay,A.E.Davies,Y.Tanaka T T. Electrodes and charge injection in low-density polyethylene. IEEE Transactions on Dielectrics and Electrical Insulation, 2001,8(6):867~873
[40] K.Fukunaga,T.Maeno,Y.Hashimuto,K.Suzuki. Space charge formation at the interface between a charge layer and a polyester film. IEEE Transactions on Dielectrics and Electrical Insulation, 1998,5:276~280
[41] G.Chen,Y.Tanaka,T.Takada L Z. Effect of polyethylene interface on space charge formation. IEEE Transactions on Dielectrics and Electrical Insulation, 2004,11(1):113~121
[42]陈季丹刘子玉.电介质物理学.机械工业出版社, 1980
[43] L.A.Dissado,C.Laurent,G.C.Montanari P H E M. Demonstrating a threshold for trapped space charge accumulation in solid dielectrics under DC field. IEEE Transactions on Dielectrics and electrical insulation, 2005,12:612~620
[44] D.Fabiani,G.C.Montanari,C.Laurent,G.Teyssedre,P.H.F.Morshuis R B. Polymeric HVDC cable design and space charge accumulation Part 1: insulation/semicon interface. IEEE electrical insulation magazine, 2007,23(6):11~19
[45] Xue Q. The influence of particle shape and size on electric conductivity of metal-polymer composites. European Polymer Journal, 2004,40:323~327
[46] Jiong Chen,YiYin,Zheli D. Study the percolation phenomenon of high field volt-ampere characteristic in the composite of low-density polyethylene/SiOx. International Symposium on Electrical Insulating Materials 2005, Kitakyushu,Japan, 2005:243~246
[47] L.I.Trusov,N.G.Askuntovich,R.P.Borovikova,M.A.Baklastov V P F. The percolation size effect. Physics Letters A, 1992,167:306~308
[48]王乐,徐曼,孙颖,鲁宁,曹晓珑.纳米银/环氧树脂复合物的电阻和击穿特性研究.绝缘材料, 2006,39(4):37~40
[49] Pelissou S., Bencaad P. G L H. electrical properties of matallocene polyethylene. 2004 internet conference on solid dielectrics, Paris, 2004:466~469
[50] M.M.Ueki M Z. Influence of additives on the dielectric strength of high-density polyethylene. IEEE Transactions on Dielectrics and electrical insulation, 1999,6(6):876~881
[51]柯扬船皮特.斯壮.聚合物-无机纳米复合材料.北京:化学工业出版社, 2003
[52]吴人洁.现代分析技术.上海科学技术出版社, 1987
[53] [日]高分子学会.高分子材料的试验方法及评价.化学工业出版社, 1988
[54]高家武.高分子材料近代测试技术.北京航空航天大学出版社, 1994
[55]吴瑾光.近代傅里叶变换红外光谱技术及应用.北京:科学技术文献出版社, 1994
[56]陈卫,孙世刚.纳米材料科学中的谱学研究.光谱学与光谱分析, 2002,22(3):504~510
[57]中西香尔PH索罗曼【著】王绪名【译】.红外光谱分析100例.科学出版社, 1984
[58]尹毅,屠德民,李明,孙晶.以自由基清除剂作为电压稳定剂的作用机理的研究.绝缘材料通讯, 1999,(6):12~16
[59]彭文世,刘高魁.矿物红外光谱图集.科学出版社, 1982
[60]李余增.热分析.清华大学出版社, 1990
[61]于伯龄.实用热分析.纺织工业出版社, 1990
[62] E.Kontou M N. Thermao-mechanical properties of LLDPE/SiO2 nanocomposites. Polymer, 2006,47:1267~1280
[63]朱爱荣,曹晓珑. 110kV交联电缆绝缘层热分析研究.电线电缆, 2005,4:26~29
[64]杨伟,单桂芳,唐雪刚,周桥成,谢邦互,杨鸣波. LLDPE吹塑薄膜的结构与性能.高分子材料科学与工程, 2006,22(4):114~117