温度对油纸绝缘空间电荷消散特性的影响
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摘要
换流变压器的出厂试验中,残留在电介质中的空间电荷将会影响绝缘试验。通过研究油纸绝缘中空间电荷的消散特性,可以为换流变压器出厂试验项目程序和时间间隔控制提供理论和试验依据,进而提出合理的试验方案。本文通过电声脉冲法和三电极法测量不同温度条件下的油浸纸试品,观察温度对油浸纸试品直流空间电荷消散特性的影响,并分析提取空间电荷总量、最大正向场强、油浸纸体积电导率等特征量。研究得到了油纸绝缘的活化能为0.48e V。随着温度升高,油纸绝缘不仅在去极化过程中空间电荷消散速度加快,在极化过程中其积聚总量也增加。去极化的初始阶段,最大正向场强出现的位置靠近阳极,随着去极化时间的延长,最大正向场强出现区域逐渐向阴极扩展。同样温度下,去极化过程中,电流达到稳定值的时间小于空间电荷总量消散达到稳定值的时间。在工厂试验和运行过程中,为避免空间电荷畸变电场造成对绝缘的损伤,去极化过程或极性反转时间间隔按照空间电荷总量消散达到稳定值的时间计算,不低于38min。
In the converter transformer's delivery test,the space charge remained in the dielectric will affect the insulation test. By studying the dissipation characteristics of space charge,it is possible to provide the theoretical and experimental basis for converter transformer delivery test program and time interval control,and then put forward to reasonable testing program. To observe the influence of temperature on space charge dissipation behavior,pulsed electroacoustic( PEA) method and three-electrode method are used to test oil-paper sample under different temperature. Besides,the space charge amount,the maximum of positive field strength and the oil-paper conductivity are calculated. The activation energy of oil paper insulation was 0. 48 e V. With the increase of temperature,space charge in oil-paper insulation not only accelerates the dissipation rate in the process of depolarization,but also increases its accumulation in the process of polarization. At the initial stage of depolarization,the maximum forward field intensity appears near the anode,and gradually toward the cathode over time. At the same temperature,during the depolarization process,the time when the current reaches a steady value is less than the time when the total space charge dissipates to a steady value. During the test and operation,in order to avoid the damage to the insulation caused by the space charge distortion electric field,the depolarization process or the polarity reversal time interval should be not less than 38 min calculated according to the time when the space charge is dissipated to a stable value.
In the converter transformer's delivery test,the space charge remained in the dielectric will affect the insulation test. By studying the dissipation characteristics of space charge,it is possible to provide the theoretical and experimental basis for converter transformer delivery test program and time interval control,and then put forward to reasonable testing program. To observe the influence of temperature on space charge dissipation behavior,pulsed electroacoustic( PEA) method and three-electrode method are used to test oil-paper sample under different temperature. Besides,the space charge amount,the maximum of positive field strength and the oil-paper conductivity are calculated. The activation energy of oil paper insulation was 0. 48 e V. With the increase of temperature,space charge in oil-paper insulation not only accelerates the dissipation rate in the process of depolarization,but also increases its accumulation in the process of polarization. At the initial stage of depolarization,the maximum forward field intensity appears near the anode,and gradually toward the cathode over time. At the same temperature,during the depolarization process,the time when the current reaches a steady value is less than the time when the total space charge dissipates to a steady value. During the test and operation,in order to avoid the damage to the insulation caused by the space charge distortion electric field,the depolarization process or the polarity reversal time interval should be not less than 38 min calculated according to the time when the space charge is dissipated to a stable value.
引文
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[12]吴锴,朱庆东,陈曦,等(Wu Kai,Zhu Qingdong,Chen Xi,et al.).温度梯度效应对油纸绝缘材料空间电荷分布特性的影响(Effect of temperature gradient on space charge distribution in oil impregnated papers)[J].高电压技术(High Voltage Engineering),2011,37(4):823-827.
[13]李锰,汪沨,王湘汉(Li Meng,Wang Feng,Wang Xianghan).不同电极结构中SF6/N2混合气体正向流注电晕放电特性(Anode-directed streamer corona discharge simulation in different electrode structures in SF6/N2gas mixtures)[J].电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2015,34(3):24-28.
[14]钟力生,李盛涛,徐传骧,等(Zhong Lisheng,Li Shengtao,Xu Chuanxiang,et al.).工程电介质物理与介电现象(Engineering dielectric physics and dielectric phenomena)[M].西安:西安交通大学出版社(Xi’an:Xi’an Jiaotong University Press),2013.
[15]唐超(Tang Chao).油纸绝缘介质的直流空间电荷特性研究(Studies on the DC space charge characteristics of oil-paper insulation materials)[D].重庆:重庆大学(Chongqing:Chongqing University),2010.
[16]周远翔,王宁华,王云杉,等(Zhou Yuanxiang,Wang Ninghua,Wang Yunshan,et al.).固体电介质空间电荷研究进展(Review of research on space charge in solid dielectrics)[J].电工技术学报(Transactions of China Electrotechnical Society),2008,23(9):16-25.
[17]黄云程,蔡金锭(Huang Yuncheng,Cai Jinding).应用去极化能量谱评估变压器绝缘老化受潮状态(Diagnosis of insulation condition of transformers by using depolarization energy spectrum)[J].电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2016,35(1):53-59.
[18]郝建(Hao Jian).变压器油纸绝缘热老化的时频域介电和空间电荷特性研究(Study on time/frequency domain dielectric spectroscopy and space charge characteristics of transformer oil-paper insulation thermal aging)[D].重庆:重庆大学(Chongqing:Chongqing University),2012.
[19]郑飞虎,张冶文,肖春(Zheng Feihu,Zhang Yewen,Xiao Chun).聚合物电介质的击穿与空间电荷的关系(Relationship between breakdown in polymer dielectrics and space charge)[J].材料科学与工程学报(Journal of Materials Science&Engineering),2006,24(2):316-320,285.
[20]周远翔,黄猛,陈维江,等(Zhou Yuanxiang,Huang Meng,Chen Weijiang,et al.).直流电场下油纸绝缘介质界面处的空间电荷特性(Space charge characteristics of the interface in oil-paper insulation under DC voltage)[J].高电压技术(High Voltage Engineering),2011,37(10):2417-2423.
[21]刘康淋,廖瑞金,赵学童(Liu Kanglin,Liao Ruijin,Zhao Xuetong).声脉冲法空间电荷测量系统的研究(Measurement of space charges in air based on sound pulse method)[J].物理学报(Acta Physica Sinica),2015,64(16):164301.
[22]Zhou Yuanxiang,Wang Ninghua,Yan Ping,et al.Annealing effect on DC conduction in polyethylene films[J].Journal of Electrostatics,2002,57(3-4):381-388.
[23]Koufakis E I,Halevidis C D,Polykrati A D,et al.Calculation of the activation energy of oil-paper insulation in a distribution transformer[J].IEEE Electrical Insulation Magazine,2012,28(2):52-58.
[24]李吉晓,张冶文,夏钟福,等(Li Jixiao,Zhang Yewen,Xia Zhongfu,et al.).空间电荷在聚合物老化和击穿过程中的作用(Space charge in polymer aging and breakdown processes)[J].科学通报(Science Bulletin),2000,45(23):2469-2475.
[2]郭少朋,韩立,徐鲁宁,等(Guo Shaopeng,Han Li,Xu Luning,et al.).光纤传感器在局部放电检测中的研究进展综述(Review of research on fiber optic sensors for partial discharge detection)[J].电工电能新技术(Advanced Technology of Electrical Engineering&Energy),2016,35(3):47-53.
[3]GB/T 18494.2-2007,变流变压器-第2部分:高压直流输电用换流变压器(Convertor transformers-Part 2:Transformers for HVDC applications)[S].
[4]CIGRE Advisory Group B4.04.HVDC LCC converter transformers-Converter transformers failure survey results from 2003 to 2012[R].2015.
[5]陈杨,蔡金锭,林燕桢(Chen Yang,Cai Jinding,Lin Yanzhen).基于油纸绝缘等效电路的变压器微水含量研究(Research of micro water content of oil-paper transformer based on oil-paper insulation system’s equivalent circuit method)[J].电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2015,34(5):47-53.
[6]金福宝,周远翔,黄猛,等(Jin Fubao,Zhou Yuanxiang,Huang Meng,et al.).老化对交直流复合电场下油纸绝缘沿面放电过程特性的影响(Effects of oil-paper aged state on characteristics of creepage discharge process under combined AC-DC voltage)[J].高电压技术(High Voltage Engineering),2015,41(12):4120-4130.
[7]Zhou Yuanxiang,Wang Yunshan,Li Guangfan,et al.Space charge phenomena in oil-paper insulation materials under high voltage direct current[J].Journal of Electrostatics,2009,67(2-3):417-421.
[8]Liu R,Jaksts A,Tornkvist C,et al.Moisture and space charge in oil-impregnated pressboard under HVDC[A].IEEE International Conference on Conduction and Breakdown in Solid Dielectrics[C].1998.17-22.
[9]廖瑞金,周之,郝建,等(Liao Ruijin,Zhou Zhi,Hao Jian,et al.).水分和温度联合作用时油浸绝缘纸空间电荷特性(Space charge characteristics of oil immersed paper under moisture and temperature effect)[J].高电压技术(High Voltage Engineering),2012,38(10):2647-2654.
[10]Hao Jian,Chen George,Liao Ruijin,et al.Influence of moisture on space charge dynamics in multilayer oil-paper insulation[J].IEEE Transactions on Dielectrics&Electrical Insulation,2012,19(4):1456-1464.
[11]Tang Chao,Chen G,Fu Mingli,et al.Space charge behavior in multi-layer oil-paper insulation under different DC voltages and temperatures[J].IEEE Transactions on Dielectrics&Electrical Insulation,2010,17(3):775-784.
[12]吴锴,朱庆东,陈曦,等(Wu Kai,Zhu Qingdong,Chen Xi,et al.).温度梯度效应对油纸绝缘材料空间电荷分布特性的影响(Effect of temperature gradient on space charge distribution in oil impregnated papers)[J].高电压技术(High Voltage Engineering),2011,37(4):823-827.
[13]李锰,汪沨,王湘汉(Li Meng,Wang Feng,Wang Xianghan).不同电极结构中SF6/N2混合气体正向流注电晕放电特性(Anode-directed streamer corona discharge simulation in different electrode structures in SF6/N2gas mixtures)[J].电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2015,34(3):24-28.
[14]钟力生,李盛涛,徐传骧,等(Zhong Lisheng,Li Shengtao,Xu Chuanxiang,et al.).工程电介质物理与介电现象(Engineering dielectric physics and dielectric phenomena)[M].西安:西安交通大学出版社(Xi’an:Xi’an Jiaotong University Press),2013.
[15]唐超(Tang Chao).油纸绝缘介质的直流空间电荷特性研究(Studies on the DC space charge characteristics of oil-paper insulation materials)[D].重庆:重庆大学(Chongqing:Chongqing University),2010.
[16]周远翔,王宁华,王云杉,等(Zhou Yuanxiang,Wang Ninghua,Wang Yunshan,et al.).固体电介质空间电荷研究进展(Review of research on space charge in solid dielectrics)[J].电工技术学报(Transactions of China Electrotechnical Society),2008,23(9):16-25.
[17]黄云程,蔡金锭(Huang Yuncheng,Cai Jinding).应用去极化能量谱评估变压器绝缘老化受潮状态(Diagnosis of insulation condition of transformers by using depolarization energy spectrum)[J].电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2016,35(1):53-59.
[18]郝建(Hao Jian).变压器油纸绝缘热老化的时频域介电和空间电荷特性研究(Study on time/frequency domain dielectric spectroscopy and space charge characteristics of transformer oil-paper insulation thermal aging)[D].重庆:重庆大学(Chongqing:Chongqing University),2012.
[19]郑飞虎,张冶文,肖春(Zheng Feihu,Zhang Yewen,Xiao Chun).聚合物电介质的击穿与空间电荷的关系(Relationship between breakdown in polymer dielectrics and space charge)[J].材料科学与工程学报(Journal of Materials Science&Engineering),2006,24(2):316-320,285.
[20]周远翔,黄猛,陈维江,等(Zhou Yuanxiang,Huang Meng,Chen Weijiang,et al.).直流电场下油纸绝缘介质界面处的空间电荷特性(Space charge characteristics of the interface in oil-paper insulation under DC voltage)[J].高电压技术(High Voltage Engineering),2011,37(10):2417-2423.
[21]刘康淋,廖瑞金,赵学童(Liu Kanglin,Liao Ruijin,Zhao Xuetong).声脉冲法空间电荷测量系统的研究(Measurement of space charges in air based on sound pulse method)[J].物理学报(Acta Physica Sinica),2015,64(16):164301.
[22]Zhou Yuanxiang,Wang Ninghua,Yan Ping,et al.Annealing effect on DC conduction in polyethylene films[J].Journal of Electrostatics,2002,57(3-4):381-388.
[23]Koufakis E I,Halevidis C D,Polykrati A D,et al.Calculation of the activation energy of oil-paper insulation in a distribution transformer[J].IEEE Electrical Insulation Magazine,2012,28(2):52-58.
[24]李吉晓,张冶文,夏钟福,等(Li Jixiao,Zhang Yewen,Xia Zhongfu,et al.).空间电荷在聚合物老化和击穿过程中的作用(Space charge in polymer aging and breakdown processes)[J].科学通报(Science Bulletin),2000,45(23):2469-2475.