电容耦合法电缆局部放电带电检测的在线校正
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摘要
为建立高压电缆高频局部放电带电检测现场在线校正方法,基于高压电缆绝缘接头外置式电容耦合局部放电检测校正回路等效电路模型,通过电缆模拟接头与真型接头的校正试验,分析了带电检测的在线校正与离线校正方法的等效关系及其影响因素;结合实际运行线路超高压电缆接头上的电容耦合法校正比对试验,提出了电容耦合法局部放电带电检测的现场在线校正与灵敏度评估方案。研究结果表明,在线与离线校正等效系数为接头绝缘法兰两侧等效电容与信号注入侧接头等效电容之比,与检测回路阻抗及旁路杂散电容无关;绝缘接头中的局部放电量受接头绝缘法兰两侧等效电容分流及杂散电容影响,现场检测灵敏度为在线校正注入中的最小可检出信号与校正等效系数之积;现场带电检测与校正中,检测用电容耦合传感器的电容值应≥500 p F,并应尽可能接近绝缘环两侧,校正用电容耦合传感器应安装在检测电容外部两侧、且具有良好对称性结构的位置以减少校正误差。
In order to establish the online correction method of high frequency partial discharge on-site test for high voltage power cable lines, on the basis of equivalent correction model of external capacitive coupling partial discharge detection circuit for high voltage cable insulation joint, we analyzed the equivalent relation of online and offline correction methods for online detection and its influencing factors according to correction tests of simulated and real cable joints. Combining with correction comparison tests of actual operating extra high voltage cable joints based on capacitance coupling method, we proposed on-site online correction and sensitivity evaluation schemes of PD detection based on capacitance coupling method. The results reveal that the equivalent coefficient of online and offline correction is equal to the ratio of the equivalent capacitance of both sides of insulation joint and the equivalent capacitance of joint on signal injection side, which is irrelevant to the impedance of detecting circuit and the stray capacitance of bypass. The detectable internal PD in insulation joint is affected by the shunting between equivalent capacitance of both sides of insulation joint and the stray capacitance, the detection sensitivity is equal to the product of the minimum detectable signal and correction coefficient in online correction. In the on-site PD detection and correction tests, the capacitance of detecting capacitive coupling sensors should not be less than 500 p F, and sensors need to be arranged as close as possible to the insulating ring on both sides; the correcting capacitive coupling sensors should be installed on the structure which is outside the detecting capacitance on both sides with good symmetry, as it can reduce the correction error.
In order to establish the online correction method of high frequency partial discharge on-site test for high voltage power cable lines, on the basis of equivalent correction model of external capacitive coupling partial discharge detection circuit for high voltage cable insulation joint, we analyzed the equivalent relation of online and offline correction methods for online detection and its influencing factors according to correction tests of simulated and real cable joints. Combining with correction comparison tests of actual operating extra high voltage cable joints based on capacitance coupling method, we proposed on-site online correction and sensitivity evaluation schemes of PD detection based on capacitance coupling method. The results reveal that the equivalent coefficient of online and offline correction is equal to the ratio of the equivalent capacitance of both sides of insulation joint and the equivalent capacitance of joint on signal injection side, which is irrelevant to the impedance of detecting circuit and the stray capacitance of bypass. The detectable internal PD in insulation joint is affected by the shunting between equivalent capacitance of both sides of insulation joint and the stray capacitance, the detection sensitivity is equal to the product of the minimum detectable signal and correction coefficient in online correction. In the on-site PD detection and correction tests, the capacitance of detecting capacitive coupling sensors should not be less than 500 p F, and sensors need to be arranged as close as possible to the insulating ring on both sides; the correcting capacitive coupling sensors should be installed on the structure which is outside the detecting capacitance on both sides with good symmetry, as it can reduce the correction error.
引文
[1]王立,杜伯学,任志刚.高压交联聚乙烯电缆绝缘劣化试验分析[J].高电压技术,2014,40(1):111-116.WANG Li,DU Boxue,REN Zhigang.Test and analysis of insulation deterioration of XLPE power cable[J].High Voltage Engineering,2014,40(1):111-116.
[2]Zhong L,Xu Y,Chen G,et al.Use of capacitive couplers for partial discharge measurements in power cables and joints[C]∥IEEE International Conference on Conduction and Breakdown in Solid Dielectrics.Eindhoven,Holland,2001:412-415.
[3]Tian Y,Lewin P L,Davies A E,et al.Comparison of on-line partial discharge detection methods for HV cable joints[J].IEEE Transactions on Dielectrics and Electrical Insulation,2002,9(4):604-615.
[4]李鹤南.高压电缆接头局放检测方法[D].北京:华北电力大学,2011:12-18.LI Henan.Partial discharge detection method for high voltage cable joint[D].Beijing,China:North China Electric Power University,2011:12-18.
[5]姜芸,闵虹,夏荣,等.高压交联电缆接头局放的电容耦合法检测及分析[J].高电压技术,2010,36(8):2005-2011.JIANG Yun,MIN Hong,XIA Rong,et al.Capacitive coupling detection and characteristic analysis of partial discharge in high-voltage XLPE power cable joints[J].High Voltage Engineering,2010,36(8):2005-2011.
[6]IEC 60270 High voltage test techniques:partial discharge measurements[S],2000.
[7]郭恒,王昌长,谈克雄.带电校正局放放电量的方法[J].电工技术学报,1990,10(3):51-55.GUO Heng,WANG Changchang,TAN Kexiong.On-line correction method for partial discharge[J].Transactions of China Electrotechnical Society,1990,10(3):51-55.
[8]Chen M K,Cheng C Y,Chen J M.Sensitivity in partial discharge detection[C]∥2011 Electrical Insulation Conference.Montreal,Canada:IEEE,2011:162-165.
[9]Ginzo K,Atsushi T,Keiichi M,et al.Development of a method of partial discharge detection in extra-high voltage cross-linked polyethylene insulated cable lines[J].IEEE Transactions on Power Delivery,1992,7(3):1068-1079.
[10]徐政,钱洁.电缆电气参数不同计算方法及其比较[J].高电压技术,2013,39(3):689-697.XU Zheng,QIAN Jie.Comparison of different methods for calculating electrical parameters of power cables[J].High Voltage Engineering,2013,39(3):689-697.
[11]Kiyoshi K,Kazunari A,Ken Y,et al.Development of failure prediction method for accessories of XLPE cable lines[C]∥Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials.[S.l.]:IEEE,1991:699-702.
[12]Gustavsen B,Martinez J A,Durbak D.Parameter determination for modeling system transients,partⅡ:insulated cables[J].IEEE Transactions on Power Delivery,2005,20(3):2045-2050.
[13]Wang P,Lewin P L,Sutton S J.Calibration of capacitive couplers for online PD detection in HV cables[J].IEEE Electrical Insulation Magazine,2005,21(3):28-39.
[14]Craatz P,Plath R,Heinrich R,et al.Sensitive online PD measurement and location using directional coupler sensors in 110 kV prefabricated joints[J].IET Conference Publication,1999,5(467):317-321.
[15]张琦.高压XLPE电缆绝缘诊断技术研究[D].长沙:长沙理工大学,2014:9-20.ZHANG Qi.The study on insulation diagnosis technique of high voltage XLPE cable[D].Changsha,China:Changsha University of Science&Technology,2014:9-20.
[16]Cavallini A,Montanari G,Carlo T,et al.PD apparent charge estimation and calibration:a critical review[J].IEEE Transactions on Dielectrics and Electrical Insulation,2010,17(1):198-205.
[2]Zhong L,Xu Y,Chen G,et al.Use of capacitive couplers for partial discharge measurements in power cables and joints[C]∥IEEE International Conference on Conduction and Breakdown in Solid Dielectrics.Eindhoven,Holland,2001:412-415.
[3]Tian Y,Lewin P L,Davies A E,et al.Comparison of on-line partial discharge detection methods for HV cable joints[J].IEEE Transactions on Dielectrics and Electrical Insulation,2002,9(4):604-615.
[4]李鹤南.高压电缆接头局放检测方法[D].北京:华北电力大学,2011:12-18.LI Henan.Partial discharge detection method for high voltage cable joint[D].Beijing,China:North China Electric Power University,2011:12-18.
[5]姜芸,闵虹,夏荣,等.高压交联电缆接头局放的电容耦合法检测及分析[J].高电压技术,2010,36(8):2005-2011.JIANG Yun,MIN Hong,XIA Rong,et al.Capacitive coupling detection and characteristic analysis of partial discharge in high-voltage XLPE power cable joints[J].High Voltage Engineering,2010,36(8):2005-2011.
[6]IEC 60270 High voltage test techniques:partial discharge measurements[S],2000.
[7]郭恒,王昌长,谈克雄.带电校正局放放电量的方法[J].电工技术学报,1990,10(3):51-55.GUO Heng,WANG Changchang,TAN Kexiong.On-line correction method for partial discharge[J].Transactions of China Electrotechnical Society,1990,10(3):51-55.
[8]Chen M K,Cheng C Y,Chen J M.Sensitivity in partial discharge detection[C]∥2011 Electrical Insulation Conference.Montreal,Canada:IEEE,2011:162-165.
[9]Ginzo K,Atsushi T,Keiichi M,et al.Development of a method of partial discharge detection in extra-high voltage cross-linked polyethylene insulated cable lines[J].IEEE Transactions on Power Delivery,1992,7(3):1068-1079.
[10]徐政,钱洁.电缆电气参数不同计算方法及其比较[J].高电压技术,2013,39(3):689-697.XU Zheng,QIAN Jie.Comparison of different methods for calculating electrical parameters of power cables[J].High Voltage Engineering,2013,39(3):689-697.
[11]Kiyoshi K,Kazunari A,Ken Y,et al.Development of failure prediction method for accessories of XLPE cable lines[C]∥Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials.[S.l.]:IEEE,1991:699-702.
[12]Gustavsen B,Martinez J A,Durbak D.Parameter determination for modeling system transients,partⅡ:insulated cables[J].IEEE Transactions on Power Delivery,2005,20(3):2045-2050.
[13]Wang P,Lewin P L,Sutton S J.Calibration of capacitive couplers for online PD detection in HV cables[J].IEEE Electrical Insulation Magazine,2005,21(3):28-39.
[14]Craatz P,Plath R,Heinrich R,et al.Sensitive online PD measurement and location using directional coupler sensors in 110 kV prefabricated joints[J].IET Conference Publication,1999,5(467):317-321.
[15]张琦.高压XLPE电缆绝缘诊断技术研究[D].长沙:长沙理工大学,2014:9-20.ZHANG Qi.The study on insulation diagnosis technique of high voltage XLPE cable[D].Changsha,China:Changsha University of Science&Technology,2014:9-20.
[16]Cavallini A,Montanari G,Carlo T,et al.PD apparent charge estimation and calibration:a critical review[J].IEEE Transactions on Dielectrics and Electrical Insulation,2010,17(1):198-205.