发电机定子绕组局部放电超声波检测系统研究
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摘要
发电机是电力系统中重要的电气设备,发电机故障主要是由绝缘引起,这些绝缘故障将威胁电力系统的安全稳定运行。通过对发电机定子绕组局部放电进行在线监测,可以判断发电机定子绝缘状况,并且可以提前发出警报,防止事故发生,对整个电力系统的稳定、安全、可靠运行有着重大意义。本文研究出一种发电机定子绕组局部放电在线监测系统。该系统是以超声波传感器作为现场敏感器件,测量局部放电产生的超声波信号,并对信号进行放大,滤波,电平抬升,A/D模数转换,以及通用串行总线传送数据,并对结果进行分析处理,提取出局部放电特征量。
使用Keil C软件编写了下位机程序,完成单片机的初始化、A/D转换、下位机USB程序,并通过USBXpress软件来获取相关的驱动程序以及API函数,实现下位机和上位机之间的USB数据通信。
基于虚拟仪器技术,结合超声波检测终端,在LabVIEW平台上开发了发电机定子绕组局部放电超声波检测软件系统。系统实现局部放电数据的接收、解码、分解和重组处理,在人机交互界面下图形化显示局部放电波形。开发了一套基于虚拟仪器的局部放电信号的小波分析软件,进行局部放电信号小波分析。建立局部放电数据库管理,实现数据库信息查询。
利用该系统对模拟局部放电信号产生的超声波在发电机定子中传播情况和发电机定子绕组的局部放电超声信号进行检测,并对不同位置放电源的检测结果进行对比,分析局部放电产生的超声信号在发电机定子中传播特性。系统成功地检测出发电机定子线棒产生的局部放电超声波信号,并利用小波去噪提取出超声波信号。
实验结果表明利用超声波检测发电机定子绕组局部放电是可行的,设计的检测系统具有较高的灵敏度和稳定性,为进一步得出局部放电产生的超声信号特征和绝缘故障之间的对应关系奠定基础。该系统进一步完善之后可指导相关人员检测发电机运行状态,及时发现故障点,有计划进行检查和维修,保证发电机正常安全运行,降低社会经济损失。
Generator is extremely important electrical equipment in power systems. Generator failure is mainly caused by the insulation failure, which will also threaten the power system security and stability. By generator stator windings partial discharge (PD) on-line monitoring, the insulation condition of the generator stator can be judged, and the alarm can also be given to prevent accidents in advance, which will have great significance on stability, security and reliable operation of the entire power system.
In the paper, on-line monitoring system of generator stator winding PD has been developed. The ultrasonic sensor has been used as system field-sensitive devices, which can gain ultrasonic signals generated by partial discharge.The ultrasonic signal is amplified, filtered, level lifted, A/D analog-digital convertered, and transfered by Universal Serial Bus(USB). The results are processed and analyzed, and then the characteristics of partial discharge have beeen extracted.
The lower machine communication is programed by Keil C, including A/D converter of PD signal, the microcontroller initialization, the USB program. The relevant drivers and API functions are getten by USBXpress software and data communications between the USB and PC are realized.
Based on virtual instrument technology and ultrasonic detection terminal, software system of generator stator windings PD ultrasonic testing is developed on the Lab VIEW platform. The software system realizes PD data receiving, decomposing and re-combining , and PD waveform is graphically displaied on human-computer interaction interface. The wavelet analysis software based on virtual instrument is developed and wavelet analysis of PD ultrasonic signal is done by the software. The database management of partial discharge is established to realize the database information inquiry.
The propagation characteristics of PD ultrasonic from PD model and PD ultrasonic in generator stator winding are detected by using the detect system. Discharge sources in different position of the generator detected by the system are analyzed and compared. Propagation characteristic of ultrasonic signals in the generator stator is analysised.The system detects ultrasonic signals of generator stator bars successfully and PD ultrasonic signal is extracted by wavelet denoising method.
Experimental results show that the proposed detection system is feasible and has high sensitivity and stability,which lay the foundations for further drawing the corresponding relationship between ultrasonic signals characteristics of PD and the insulation fault. With further improved, the system can detect operation state and failure point of the generator and realize planned inspection and maintenance, ensure that generators safely operate which will reduce the social economic losses effectively.
使用Keil C软件编写了下位机程序,完成单片机的初始化、A/D转换、下位机USB程序,并通过USBXpress软件来获取相关的驱动程序以及API函数,实现下位机和上位机之间的USB数据通信。
基于虚拟仪器技术,结合超声波检测终端,在LabVIEW平台上开发了发电机定子绕组局部放电超声波检测软件系统。系统实现局部放电数据的接收、解码、分解和重组处理,在人机交互界面下图形化显示局部放电波形。开发了一套基于虚拟仪器的局部放电信号的小波分析软件,进行局部放电信号小波分析。建立局部放电数据库管理,实现数据库信息查询。
利用该系统对模拟局部放电信号产生的超声波在发电机定子中传播情况和发电机定子绕组的局部放电超声信号进行检测,并对不同位置放电源的检测结果进行对比,分析局部放电产生的超声信号在发电机定子中传播特性。系统成功地检测出发电机定子线棒产生的局部放电超声波信号,并利用小波去噪提取出超声波信号。
实验结果表明利用超声波检测发电机定子绕组局部放电是可行的,设计的检测系统具有较高的灵敏度和稳定性,为进一步得出局部放电产生的超声信号特征和绝缘故障之间的对应关系奠定基础。该系统进一步完善之后可指导相关人员检测发电机运行状态,及时发现故障点,有计划进行检查和维修,保证发电机正常安全运行,降低社会经济损失。
Generator is extremely important electrical equipment in power systems. Generator failure is mainly caused by the insulation failure, which will also threaten the power system security and stability. By generator stator windings partial discharge (PD) on-line monitoring, the insulation condition of the generator stator can be judged, and the alarm can also be given to prevent accidents in advance, which will have great significance on stability, security and reliable operation of the entire power system.
In the paper, on-line monitoring system of generator stator winding PD has been developed. The ultrasonic sensor has been used as system field-sensitive devices, which can gain ultrasonic signals generated by partial discharge.The ultrasonic signal is amplified, filtered, level lifted, A/D analog-digital convertered, and transfered by Universal Serial Bus(USB). The results are processed and analyzed, and then the characteristics of partial discharge have beeen extracted.
The lower machine communication is programed by Keil C, including A/D converter of PD signal, the microcontroller initialization, the USB program. The relevant drivers and API functions are getten by USBXpress software and data communications between the USB and PC are realized.
Based on virtual instrument technology and ultrasonic detection terminal, software system of generator stator windings PD ultrasonic testing is developed on the Lab VIEW platform. The software system realizes PD data receiving, decomposing and re-combining , and PD waveform is graphically displaied on human-computer interaction interface. The wavelet analysis software based on virtual instrument is developed and wavelet analysis of PD ultrasonic signal is done by the software. The database management of partial discharge is established to realize the database information inquiry.
The propagation characteristics of PD ultrasonic from PD model and PD ultrasonic in generator stator winding are detected by using the detect system. Discharge sources in different position of the generator detected by the system are analyzed and compared. Propagation characteristic of ultrasonic signals in the generator stator is analysised.The system detects ultrasonic signals of generator stator bars successfully and PD ultrasonic signal is extracted by wavelet denoising method.
Experimental results show that the proposed detection system is feasible and has high sensitivity and stability,which lay the foundations for further drawing the corresponding relationship between ultrasonic signals characteristics of PD and the insulation fault. With further improved, the system can detect operation state and failure point of the generator and realize planned inspection and maintenance, ensure that generators safely operate which will reduce the social economic losses effectively.
引文
[1]吴广宁.大型发电机故障放电在线监测及诊断技术[M].成都:西南交通大学出版社,2001.
[2]苏鹏声,汪小明,曹海翔,等.大型发电机定子绕组局部放电在线监测系统的研究[J].电工电能新技术,2000(2):49-52.
[3]蒋远东.大型发电机定子绕组局部放电在线监测系统的研制[D].哈尔滨理工大学硕士学位论文. 2007.
[4]陈卓,刘念,薄丽雅,等.大型发电机定子绕组局部放电在线检测方法的研究[J].电力自动化设备,2005(6):22-25.
[5]国家标准局.旋转电机定子线棒及绕组局部放电的测量方法及评定导则,中华人民共和国国家标准. 2007,GB/T 20833.
[6]国家标准局.局部放电测量,中华人民共和国国家标准. 1987,GB7354-87.
[7]马宏忠.电机状态监测与故障诊断[M].北京:机械工业出版社,2007.
[8] KIM Y J,HWANI D H,SHIN B C. Development of Partial Discharge Monitoring System for Generator Stator Insulations[C]. IEEE. Conference Record of the 2003 IEEE International Symposium on Electical Insulation, Anaheim, USA, 2003,2(5):164-175.
[9] WANG W, LI W, SU Q. The Estimation of Insulation Condition of Generators by On-line Monitoring of the 2002 IEEE Intemational Symposium on Electrical Insulation, Boston, MA USA, April 7-10, 2002: 40-43.
[10]黄成军,郁惟镛.局部放电在线监测及其在大型电机中的应用[J].大电机技术2000(6): 33-38.
[11]王昌长,李福祺,高胜友.电力设备的在线监测与故障诊断[M].北京:清华大学出版社, 2006.
[12]郭俊,吴广宁,张血琴.局部放电检测技术的现状和发展[J].电工技术学报, 2005,20(2):32-34
[13] YUE Bo, CHEN Xiao-lin, CHENG Yong-hong, et al. Diagnosis of stator winding insulation of large generator based on partial discharge measurement[J]. IEEE Transaction on Energy Conversion, 2006, 21(2): 387-395.
[14] Mangeret R,Farenc J,Ai B,et al. Optical detection of partial discharges using fluorescent fiber,IEEE Trans.On electrical insulation,1991,26(4):783~789.
[15]张毅刚,郁惟镛,黄成军,等.发电机局部放电在线监测研究的现状与展望[J].高电压技术, 2002,28(12):32-35.
[16] Stone C S, Sedding H G, Costello M J. Application of partial discharge testing to motor and generator stator winding maintenance[J]. IEEE Transactions on Energy Conversion, 1996,32(2):459-464.
[17] Kim S D. Electrical and microstructure properties of large turbie generator stator insulations[J]. IEEE International Conference on Solid Dielectrics, 2004,1(1):478-481.
[18]杨合民,李超晖,王宏.基于局部放电监测的水轮发电机主绝缘诊断分析系统[J].电力系统自动化,2004, 28 (15): 61-65.
[19] A.J.M.Pemen. Propagation of Partial Discharge Signal in Stator Winding of Turbine Generators. IEEE Transaction on Energy Conversion, 2006, 21 (1) :155-161
[20]舒乃秋,胡芳,周粲.超声传感技术在电气设备故障诊断中的应用[J].传感器技术,2003,22(5) : 1-4.
[21] HAO Yan-peng, WANG Guo-li, JIA Zhi-dogn. Application of ultrasonic pulse-echo method to insulaion condition diagnosis for large generators[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2005, 12(1):104-113.
[22] Kweon D J, Chin S B, Kwak H R, et al. The analysis of ultrasonic signals by partial discharge and noise from the transformer[J]. IEEE Transactions on Power Delivery, 2005, 20(3):1976-1983.
[23] Jones S L. The detection of partial discharge in power transformers using computer aided acoustic emission techniques[DB/OL]. IEEE Int Synod Electric Insulation Toronto Ont, June 3-6,1990. http://intl.ieeexplore.ieee.org.
[24] Dong-Jin Kweon, Sang-Bum Chin, Hee-Ro Kwak, etc. The Analysis of Ultrasonic Signals by Partial Discharge and Noise from the Transformer[J]. IEEE Transactions on Power Delivery, 2005, 20(3): 1976-1983.
[25]郝艳捧,王国利,谢恒堃,等.基于局部放电和超声波法研究大电机定子绝缘老化特性[J].电工技术学报,2002.17(2):1~6.
[26] Lundgakrd L E, Xiv P D. Acoustic partial discharge etection-practical application[J]. IEEE Electrical Insulation Magazine,1992,8(5):34-43.
[27]刘立生,邱阿瑞.高压电机局部放电在线监测方法[J].电工电能新技术, 1999(3):23-27.
[28] Michael. G,Danikas,The Definitions Used for Partial Discharge Phenomena,IEEE Transactions on Dielectrics and Electrical Insulation,1993, 28 (6) : 1075～1081.
[29] Gutfleish F,Niemeyer L. Measurement and simulation of PD in epoxy voids,IEEE Transactions on Dielectrics and Electrical Insulation,1995, 2 (5) : 729～743.
[30] Unsworth J, Talli D. Relocatable transducer heads for remote Siemens on-line PD monitor for high voltage transformers, Proceeding of the 1st international conference on insulationcondition monitoring of electrical plant, Wuhan, 24th~26th September, 2000, 254~259.
[31]王旭红.高压电机的局部放电及其在线监测方法[J].长沙电力学院学报(自然科学版). 2002,17(1): 23-26.
[32] Contin, G.Rabach. PD Analysis of Rotating ac Machines. IEEE Transactions on Dielectrics and Electrical Insulation, 1993, 28 (6) : 1033~1042.
[33]杨莉,全玉生,周跃峰.大型发电机定子绕组故障放电的特性与识别[J].电工电能新技术, 1999(2): 77-80.
[34]邓辉,蒋建国,曹海翔.大型汽轮发电机定子绕组的脉冲传播模型[J].中国电机工程学报, 1999, 19(8): 7-11.
[35]袁易全.局部放电超声特性实验研究[J].电工技术学报, 1992, 2(1): 18-23.
[36] Itoh K, Kaneda Y, Kimura K, et al. New noise rejection techniques on pulse by pulse basis for on-line partial discharge measurement of turbine generators. IEEE trans. on Energy Conversion, 1996, 11 (3) : 5852592.
[37]周力行,何蕾.变压器局部放电超声信号特性及放电源定位[J].高电压技术,2003, 29 (5) : 11-14.
[38]时书丽,赵国兴.声发射传感器技术与应用[J].仪表技术与传感器, 1998, 2: 34-37.
[39]孙才新,罗兵,赵文麒,等,用于变压器局部放电源定位测量的高灵敏度超声波传感器的研究[J].仪器仪表学报,1997,18(5): 453-458.
[40] Bruce Cartery,Ron Mancini.运算放大器权威指南[M].北京:人民邮电出版社,2010.
[41] Arthur B. Williams,Fred J. Taylor.电子滤波器设计[M].北京:科学出版社, 2008.
[42]鲍可进. C8051F单片机原理及应用[M].北京:中国电力出版社, 2006.
[43]章长飞. C8051F系列单片机开发与C语言编程[M].北京:北京航空航天大学出版社, 2005.
[44]何立民.单片机应用系统设计[M].北京:北京航空航天大学出版社, 2002.
[45]肖踞雄,翁铁成,宋中庆. USB技术及应用设计[M].北京:清华大学出版社, 2003.
[46]张念淮,江浩. USB总线接口开发指南[M].北京:国防工业出版社, 2001.
[47]朱磊.基于C8051F340的低成本数据采集器设计[J].国外电子元器件, 2008, 4(4): 6-8.
[48]岂兴明,周建兴,娇津毅.基于LabVIEW8.2中文版入门与典型事例[M].北京:人民邮电出版社,2008.
[49]雷振山,赵晨光,魏丽. LabVIEW8.2基础教程[M].北京:中国铁道出版社, 2008.
[50] Silicon Lab. USBXpress Programmer’s Guide [EB/OL]. http: //www. silabs.com /tgwWebApp /public/webcontent/products/Microcontrollers/USB/en/USBXpress. htm , 2007.
[51]覃华,刘云鹏,律方成.小波变换在局部放电在线检测干扰中的应用[J].电力科学与工程, 2003, (3): 58-60.
[52] MA X,ZHOU C, KEMP I J. Automated Wavelet Selection and Thresholding for PD Detection[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2002, 18(2): 37-45.
[53]张德丰. MATLAB小波分析[M].北京:机械工业出版社, 2009.1.
[54]覃华.基于虚拟仪器的变压器局部放电在线监测系统的研究[D].河北:华北电力大学, 2004.
[55]刘明军.基于虚拟仪器技术的GIS局部放电超高频在线监测系统的研究[D].重庆:重庆大学, 2006.
[2]苏鹏声,汪小明,曹海翔,等.大型发电机定子绕组局部放电在线监测系统的研究[J].电工电能新技术,2000(2):49-52.
[3]蒋远东.大型发电机定子绕组局部放电在线监测系统的研制[D].哈尔滨理工大学硕士学位论文. 2007.
[4]陈卓,刘念,薄丽雅,等.大型发电机定子绕组局部放电在线检测方法的研究[J].电力自动化设备,2005(6):22-25.
[5]国家标准局.旋转电机定子线棒及绕组局部放电的测量方法及评定导则,中华人民共和国国家标准. 2007,GB/T 20833.
[6]国家标准局.局部放电测量,中华人民共和国国家标准. 1987,GB7354-87.
[7]马宏忠.电机状态监测与故障诊断[M].北京:机械工业出版社,2007.
[8] KIM Y J,HWANI D H,SHIN B C. Development of Partial Discharge Monitoring System for Generator Stator Insulations[C]. IEEE. Conference Record of the 2003 IEEE International Symposium on Electical Insulation, Anaheim, USA, 2003,2(5):164-175.
[9] WANG W, LI W, SU Q. The Estimation of Insulation Condition of Generators by On-line Monitoring of the 2002 IEEE Intemational Symposium on Electrical Insulation, Boston, MA USA, April 7-10, 2002: 40-43.
[10]黄成军,郁惟镛.局部放电在线监测及其在大型电机中的应用[J].大电机技术2000(6): 33-38.
[11]王昌长,李福祺,高胜友.电力设备的在线监测与故障诊断[M].北京:清华大学出版社, 2006.
[12]郭俊,吴广宁,张血琴.局部放电检测技术的现状和发展[J].电工技术学报, 2005,20(2):32-34
[13] YUE Bo, CHEN Xiao-lin, CHENG Yong-hong, et al. Diagnosis of stator winding insulation of large generator based on partial discharge measurement[J]. IEEE Transaction on Energy Conversion, 2006, 21(2): 387-395.
[14] Mangeret R,Farenc J,Ai B,et al. Optical detection of partial discharges using fluorescent fiber,IEEE Trans.On electrical insulation,1991,26(4):783~789.
[15]张毅刚,郁惟镛,黄成军,等.发电机局部放电在线监测研究的现状与展望[J].高电压技术, 2002,28(12):32-35.
[16] Stone C S, Sedding H G, Costello M J. Application of partial discharge testing to motor and generator stator winding maintenance[J]. IEEE Transactions on Energy Conversion, 1996,32(2):459-464.
[17] Kim S D. Electrical and microstructure properties of large turbie generator stator insulations[J]. IEEE International Conference on Solid Dielectrics, 2004,1(1):478-481.
[18]杨合民,李超晖,王宏.基于局部放电监测的水轮发电机主绝缘诊断分析系统[J].电力系统自动化,2004, 28 (15): 61-65.
[19] A.J.M.Pemen. Propagation of Partial Discharge Signal in Stator Winding of Turbine Generators. IEEE Transaction on Energy Conversion, 2006, 21 (1) :155-161
[20]舒乃秋,胡芳,周粲.超声传感技术在电气设备故障诊断中的应用[J].传感器技术,2003,22(5) : 1-4.
[21] HAO Yan-peng, WANG Guo-li, JIA Zhi-dogn. Application of ultrasonic pulse-echo method to insulaion condition diagnosis for large generators[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2005, 12(1):104-113.
[22] Kweon D J, Chin S B, Kwak H R, et al. The analysis of ultrasonic signals by partial discharge and noise from the transformer[J]. IEEE Transactions on Power Delivery, 2005, 20(3):1976-1983.
[23] Jones S L. The detection of partial discharge in power transformers using computer aided acoustic emission techniques[DB/OL]. IEEE Int Synod Electric Insulation Toronto Ont, June 3-6,1990. http://intl.ieeexplore.ieee.org.
[24] Dong-Jin Kweon, Sang-Bum Chin, Hee-Ro Kwak, etc. The Analysis of Ultrasonic Signals by Partial Discharge and Noise from the Transformer[J]. IEEE Transactions on Power Delivery, 2005, 20(3): 1976-1983.
[25]郝艳捧,王国利,谢恒堃,等.基于局部放电和超声波法研究大电机定子绝缘老化特性[J].电工技术学报,2002.17(2):1~6.
[26] Lundgakrd L E, Xiv P D. Acoustic partial discharge etection-practical application[J]. IEEE Electrical Insulation Magazine,1992,8(5):34-43.
[27]刘立生,邱阿瑞.高压电机局部放电在线监测方法[J].电工电能新技术, 1999(3):23-27.
[28] Michael. G,Danikas,The Definitions Used for Partial Discharge Phenomena,IEEE Transactions on Dielectrics and Electrical Insulation,1993, 28 (6) : 1075～1081.
[29] Gutfleish F,Niemeyer L. Measurement and simulation of PD in epoxy voids,IEEE Transactions on Dielectrics and Electrical Insulation,1995, 2 (5) : 729～743.
[30] Unsworth J, Talli D. Relocatable transducer heads for remote Siemens on-line PD monitor for high voltage transformers, Proceeding of the 1st international conference on insulationcondition monitoring of electrical plant, Wuhan, 24th~26th September, 2000, 254~259.
[31]王旭红.高压电机的局部放电及其在线监测方法[J].长沙电力学院学报(自然科学版). 2002,17(1): 23-26.
[32] Contin, G.Rabach. PD Analysis of Rotating ac Machines. IEEE Transactions on Dielectrics and Electrical Insulation, 1993, 28 (6) : 1033~1042.
[33]杨莉,全玉生,周跃峰.大型发电机定子绕组故障放电的特性与识别[J].电工电能新技术, 1999(2): 77-80.
[34]邓辉,蒋建国,曹海翔.大型汽轮发电机定子绕组的脉冲传播模型[J].中国电机工程学报, 1999, 19(8): 7-11.
[35]袁易全.局部放电超声特性实验研究[J].电工技术学报, 1992, 2(1): 18-23.
[36] Itoh K, Kaneda Y, Kimura K, et al. New noise rejection techniques on pulse by pulse basis for on-line partial discharge measurement of turbine generators. IEEE trans. on Energy Conversion, 1996, 11 (3) : 5852592.
[37]周力行,何蕾.变压器局部放电超声信号特性及放电源定位[J].高电压技术,2003, 29 (5) : 11-14.
[38]时书丽,赵国兴.声发射传感器技术与应用[J].仪表技术与传感器, 1998, 2: 34-37.
[39]孙才新,罗兵,赵文麒,等,用于变压器局部放电源定位测量的高灵敏度超声波传感器的研究[J].仪器仪表学报,1997,18(5): 453-458.
[40] Bruce Cartery,Ron Mancini.运算放大器权威指南[M].北京:人民邮电出版社,2010.
[41] Arthur B. Williams,Fred J. Taylor.电子滤波器设计[M].北京:科学出版社, 2008.
[42]鲍可进. C8051F单片机原理及应用[M].北京:中国电力出版社, 2006.
[43]章长飞. C8051F系列单片机开发与C语言编程[M].北京:北京航空航天大学出版社, 2005.
[44]何立民.单片机应用系统设计[M].北京:北京航空航天大学出版社, 2002.
[45]肖踞雄,翁铁成,宋中庆. USB技术及应用设计[M].北京:清华大学出版社, 2003.
[46]张念淮,江浩. USB总线接口开发指南[M].北京:国防工业出版社, 2001.
[47]朱磊.基于C8051F340的低成本数据采集器设计[J].国外电子元器件, 2008, 4(4): 6-8.
[48]岂兴明,周建兴,娇津毅.基于LabVIEW8.2中文版入门与典型事例[M].北京:人民邮电出版社,2008.
[49]雷振山,赵晨光,魏丽. LabVIEW8.2基础教程[M].北京:中国铁道出版社, 2008.
[50] Silicon Lab. USBXpress Programmer’s Guide [EB/OL]. http: //www. silabs.com /tgwWebApp /public/webcontent/products/Microcontrollers/USB/en/USBXpress. htm , 2007.
[51]覃华,刘云鹏,律方成.小波变换在局部放电在线检测干扰中的应用[J].电力科学与工程, 2003, (3): 58-60.
[52] MA X,ZHOU C, KEMP I J. Automated Wavelet Selection and Thresholding for PD Detection[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2002, 18(2): 37-45.
[53]张德丰. MATLAB小波分析[M].北京:机械工业出版社, 2009.1.
[54]覃华.基于虚拟仪器的变压器局部放电在线监测系统的研究[D].河北:华北电力大学, 2004.
[55]刘明军.基于虚拟仪器技术的GIS局部放电超高频在线监测系统的研究[D].重庆:重庆大学, 2006.