运行条件对换流变压器油纸绝缘油流带电特性的影响
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摘要
为揭示运行条件对换流变压器内部油流带电特性的影响规律,在实验室开展了典型平板电极结构下油纸绝缘油流带电特性的研究,并分析了温度、含水率和外施直流电压幅值对冲流电流的影响机理。试验结果表明:无外施电压时,冲流电流随含水率的增加呈减小趋势,随流速和温度的增加呈增大趋势;在外施直流电压下,冲流电流随外施电压幅值和温度的增加呈增大趋势;在低温和低外施电压下冲流电流随含水率的增加呈先增大后减小趋势,而在高温或高外施电压下冲流电流随含水率的增加呈减小趋势。理论分析表明:无外施电压时,温度和含水率通过影响绝缘纸板中离子扩散系数和油侧双电层厚度来影响油流带电特性;外施直流电压会加速绝缘纸板中离子的迁移速度,进而引起低含水率下油纸绝缘中冲流电流的显著提高;冲流电流与油纸绝缘中离子数密度和离子迁移率密切相关,温度及含水率的变化会造成油和纸板中离子数密度和离子迁移率的变化存在较大的差异,进而对油纸绝缘油流带电特性产生影响。
In order to reveal the influence of operation conditions on flow electrification characteristics in converter transformer, we researched the flow electrification characteristics of oil-paper insulation with the typical plane electrode structure, and discussed the influence mechanism such as temperature, moisture content and excited DC voltage amplitude on streaming current. The experiment results show that the streaming current decreases as the moisture content decreases in the absence of an excited voltage, and it increases as the temperature and oil flow velocity increase in the absence of an excited voltage. The streaming current increases as the excited voltage amplitude and temperature increase, it increases firstly and then decreases as the moisture content increases at a low temperature and a low excited voltage, and it decreases as the moisture content increases at a high temperature or a high excited voltage. The theoretical analysis shows that, in the absence of an excited voltage, the temperature and moisture content can influence the flow electrification characteristics by affecting the ions diffusion coefficient in the insulation paper and thickness of the electric double layer in oil. The excited DC voltage will accelerate the migration velocity of ions in insulating paper, resulting in the significant increment of streaming current in oil-paper insulation at a low moisture content. Streaming current is closely related to the ions concentration and ions mobility in oil-paper insulation. The flow electrification characteristics of oil-paper insulation will be influenced by the variation of temperature and moisture content via different variations of ions concentration and ions mobility in oil and paper.
In order to reveal the influence of operation conditions on flow electrification characteristics in converter transformer, we researched the flow electrification characteristics of oil-paper insulation with the typical plane electrode structure, and discussed the influence mechanism such as temperature, moisture content and excited DC voltage amplitude on streaming current. The experiment results show that the streaming current decreases as the moisture content decreases in the absence of an excited voltage, and it increases as the temperature and oil flow velocity increase in the absence of an excited voltage. The streaming current increases as the excited voltage amplitude and temperature increase, it increases firstly and then decreases as the moisture content increases at a low temperature and a low excited voltage, and it decreases as the moisture content increases at a high temperature or a high excited voltage. The theoretical analysis shows that, in the absence of an excited voltage, the temperature and moisture content can influence the flow electrification characteristics by affecting the ions diffusion coefficient in the insulation paper and thickness of the electric double layer in oil. The excited DC voltage will accelerate the migration velocity of ions in insulating paper, resulting in the significant increment of streaming current in oil-paper insulation at a low moisture content. Streaming current is closely related to the ions concentration and ions mobility in oil-paper insulation. The flow electrification characteristics of oil-paper insulation will be influenced by the variation of temperature and moisture content via different variations of ions concentration and ions mobility in oil and paper.
引文
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[17]?UKOWSKI P,KO?TUNOWICZ T N,KIERCZY?SKI K,et al.Assessment of water content in an impregnated pressboard based on DC conductivity measurements theoretical assumptions[J].IEEETransactions on Dielectrics and Electrical Insulation,2014,21(3):1268-1275.
[18]林建忠,阮晓东,陈邦国,等.流体力学[M].北京:清华大学出版社,2005:297-298.LIN Jianzhong,RUAN Xiaodong,CHEN Bangguo,et al.Fluid mechanics[M].Beijing,China:Tsinghua University Press,2005:297-298.
[19]鲍重光.静电技术原理[M].北京:北京理工大学出版社,1993:276-282.BAO Chongguang.Theory of electrostatic technology[M].Beijing,China:Beijing Institute Technology Press,1993:276-282.
[20]MORIN A J,ZAHN M,MELCHER J R.Fluid electrification measurements of transformer pressboard/oil insulation in a couette charger[J].IEEE Transactions on Electrical Insulation,1991,26(5):870-901.
[21]HIROTAKA M,KOSEI T,KOJI K.Novel charge generation model for simulation of streaming current based on shearing stress at the oil/pressboard interface[C]∥2007 Annual Report-Conference on Electrical Insulation and Dielectric Phenomena.Vancouver,Canada:[s.n.],2007:380-383.
[22]KOSEI T,HIROTAKA M,KOJI K.A simulation method for streaming electrification by direct current field analysis[C]∥2007 Annual Report-Conference on Electrical Insulation and Dielectric Phenomena.Vancouver,Canada:[s.n.],2007:485-488.
[23]OOMMEN T V,LINDGREN S R.Streaming electrification study of transformer insulation system using a paper tube model[J].IEEETransactions on Power Delivery,1990,5(2):972-983.
[24]马志青.变温及老化条件下油纸绝缘间水分分布的研究[D].北京:华北电力大学,2013.MA Zhiqing.Moisture distribution in oil-paper insulation under variable temperature and ageing conditions[D].Beijing,China:North China Electric Power University,2013.
[2]PAILLAT T,ZELU Y,MORIN G,et al.Ester oils and flow electrification hazards in power transformers[J].IEEE Transactions on Dielectrics and Electrical Insulation,2012,19(5):1537-1543.
[3]EL-ADAWY M,PAILLAT T,TOUCHARD G,et al.Numerical Simulation of the electrical double layer development:physicochemical model at the solid and dielectric liquid interface for laminar flow electrification phenomenon[J].IEEE Transactions on Dielectrics and Electrical Insulation,2011,18(5):1463-1475.
[4]VAZQUEZ-GARCIA J,RIVENC J,AGNERAY A,et al.A critical approach to measure streaming current:case of fuels flowing through conductive and insulating polymer pipes[J].IEEE Transactions on Industry Applications,2005,41(5):1335-1342.
[5]RADWAN R M,EL-DEWIENY R M,AISH T D,et al.Factors affecting transformer oil flow electrification in electric power apparatus[C]∥Annual Report Electrical Insulation and Dielectric Phenomena.Pocono Manor,USA:[s.n.],1990:642-647.
[6]METWALLY I A.Flow electrification of transformer oil effects of mixed fields[J].IEEE Transactions on Dielectrics and Electrical Insulation,1998,5(4):518-526.
[7]WU H,JAYARAM S.DC field effects on streaming electrification in insulating oils[J].IEEE Transactions on Dielectrics and Electrical Insulation,1996,3(4):499-506.
[8]HUANG Y J,CHI X C,YANG J X,et al.Experimental observation on the charge density of transformer oil[C]∥Proceedings of Conference on Electrical Insulation and Dielectric Phenomena.Millbrae,USA:[s.n.],1996:200-203.
[9]陈庆国,高源,池明赫,等.交直流叠加电场下油纸绝缘的油流带电特性[J].中国电机工程学报,2014,34(15):2502-2510.CHEN Qingguo,GAO Yuan,CHI Minghe,et al.Flow electrification characteristics of oil-paper insulation under AC superimposed DCelectric field[J].Proceedings of the CSEE,2014,34(15):2502-2510.
[10]陈庆国,高源,池明赫,等.直流电场下典型油纸绝缘结构油流带电特性[J].高电压技术,2014,40(4):995-1001.CHEN Qingguo,GAO Yuan,CHI Minghe,et al.Flow electrification characteristics of typical oil-pressboard insulation under DC electric field[J].High Voltage Engineering,2014,40(4):995-1001.
[11]陈庆国,林林,高源,等.换流变压器中典型平板油纸绝缘结构的油流带电特性[J].电机与控制学报,2015,19(2):14-19.CHEN Qingguo,LIN Lin,GAO Yuan,et al.Flow electrification characteristics of typical oil-pressboard insulation in converter transformer[J].Electric Machines and Control,2015,19(2):14-19.
[12]吴宗汉.基础静电学[M].北京:北京大学出版社,2010:30-67.WU Zonghan.Basic electrostatics[M].Beijing,China:Peking University Press,2010:30-67.
[13]张小平.胶体界面与吸附教程[M].广州:华南理工大学出版社,2008:147-149.ZHANG Xiaoping.Course of colloid interface and adsorption[M].Guangzhou,China:South China University of Technology Press,2008:147-149.
[14]YAMADA N,KISHI A,NITTA T,et al.Model approach to the static electrification phenomena induced by the flow of oil in large power transformers[J].IEEE Transactions on Power Apparatus and Systems,1980,99(3):1097-1106.
[15]MIYAO H,HIGAKI M,KAMATA Y.Influence of AC and DC fields on streaming electrification of transformer oil[J].IEEE Transactions on Electrical Insulation,1988,23(1):129-135.
[16]涂愈明,王赞基,江缉光,等.变压器油流带电数学模型的研究及其应用第一部分:数学模型的推导[J].中国电机工程学报,1998,18(2):35-39.TU Yuming,WANG Zanji,JIANG Jiguang,et al.Study on the mathematical model for the static electrification in transformers and its application part 1:development of the mathematical model[J].Proceedings of the CSEE,1998,18(2):35-39.
[17]?UKOWSKI P,KO?TUNOWICZ T N,KIERCZY?SKI K,et al.Assessment of water content in an impregnated pressboard based on DC conductivity measurements theoretical assumptions[J].IEEETransactions on Dielectrics and Electrical Insulation,2014,21(3):1268-1275.
[18]林建忠,阮晓东,陈邦国,等.流体力学[M].北京:清华大学出版社,2005:297-298.LIN Jianzhong,RUAN Xiaodong,CHEN Bangguo,et al.Fluid mechanics[M].Beijing,China:Tsinghua University Press,2005:297-298.
[19]鲍重光.静电技术原理[M].北京:北京理工大学出版社,1993:276-282.BAO Chongguang.Theory of electrostatic technology[M].Beijing,China:Beijing Institute Technology Press,1993:276-282.
[20]MORIN A J,ZAHN M,MELCHER J R.Fluid electrification measurements of transformer pressboard/oil insulation in a couette charger[J].IEEE Transactions on Electrical Insulation,1991,26(5):870-901.
[21]HIROTAKA M,KOSEI T,KOJI K.Novel charge generation model for simulation of streaming current based on shearing stress at the oil/pressboard interface[C]∥2007 Annual Report-Conference on Electrical Insulation and Dielectric Phenomena.Vancouver,Canada:[s.n.],2007:380-383.
[22]KOSEI T,HIROTAKA M,KOJI K.A simulation method for streaming electrification by direct current field analysis[C]∥2007 Annual Report-Conference on Electrical Insulation and Dielectric Phenomena.Vancouver,Canada:[s.n.],2007:485-488.
[23]OOMMEN T V,LINDGREN S R.Streaming electrification study of transformer insulation system using a paper tube model[J].IEEETransactions on Power Delivery,1990,5(2):972-983.
[24]马志青.变温及老化条件下油纸绝缘间水分分布的研究[D].北京:华北电力大学,2013.MA Zhiqing.Moisture distribution in oil-paper insulation under variable temperature and ageing conditions[D].Beijing,China:North China Electric Power University,2013.