Abstract：As key electrical equipment, the operational continuity and reliability of pumped storage units are significant to the construction of new power systems. During operation, the inter-turn insulation of the excitation winding is susceptible to deterioration due to multiple factors, such as unbalanced electromagnetic force, thermal stress, and external mechanical stress. It is important to quickly and accurately extract the early weak fault characteristics of inter-turn short circuits (ITSC) and organize timely condition maintenance. The condition monitoring of ITSC faults in the excitation winding is susceptible to dynamic/static eccentricity and armature response, and early fault characteristics are hard to identify. Therefore, this study proposes a fault diagnosis method based on a time-frequency circulating current (TFMCC) map. Firstly, this study derives the equations for the same phase multi-branch circulating current in the dynamic/static eccentricity and static eccentricity composite ITSC states, and obtains the characteristic harmonics of the circulating current in each state. Secondly, a two-dimensional finite element simulation model of 334 MV·A is constructed, and the magnitude of the same phase branch circulating current under each state is calculated. Comparative experiments have verified that TFMCC can effectively distinguish between eccentricity, armature reaction disturbance, and ITSC faults. Finally, based on the salient synchronous generator simulation platform, the operating conditions of ITSC with different fault levels are simulated. Simulation results show that changes in the dynamic/static eccentricity degree cause the time domain amplitude of circulating current changes, and the armature response and dynamic eccentricity also cause the appearance of characteristic fractional harmonics. Accordingly, ITSC fault diagnosis by a single-time domain analysis or spectrum analysis can easily lead to fault misclassification. The TFMCC allows the fault to be located at the moment of occurrence. The signal intensity at the characteristic frequencies (5.5, 11, 22, 28, 39, 44.5 Hz) is significantly enhanced compared to the normal state. Meanwhile, a comparison with the dynamic/static eccentricity shows that the signal intensity of the dynamic eccentricity is mainly concentrated at 55.5 Hz, and the static eccentricity is mainly concentrated at 50 Hz. The signal intensity distribution is differentiated from that of ITSC faults. The ratio of the signal intensity difference energy (SIDER) are 7.13% and 13.96% for the no-load ITSC condition, and 6.66% and 13.44% for the load ITSC condition, much greater than zero, which can effectively identify the ITSC faults. The experiments on salient synchronous generator show that: the TFMCC of static eccentric compound ITSC 2.5%, 5%, and 7.5% under no-load conditions, the signal intensity at the intersection of time and characteristic frequency has changed significantly, and the signal intensity differences at 25 Hz before and after the fault are 13.05, 21.06, and 29.86 dB, respectively. The SIDER are 4.16%, 5.23%, and 11.11%, respectively. Meanwhile, the static eccentricity compound ITSC of 1%, 2.5%, and 4.9% under load conditions, and the signal intensity differences at 25 Hz before and after the fault are 29.64, 38.56, and 71.81 dB, respectively. The SIDER are 2.28%, 3.13%, and 15.68%, respectively, which shows that the method can effectively detect weak ITSC faults and locate the time of fault occurrence. The experimental results demonstrate that the method eliminates static eccentricity and armature response disturbances, and visualizes the operating conditions of the unit with a three-dimensional map that includes operating time, characteristic frequency, and signal intensity. At the same time, to effectively identify weak ITSC faults, this study also calculates that the SIDER of the time-frequency matrix can further quantify the magnitude of the fault and prevent false alarms, which can provide guidance for field operation and inspection personnel to carry out condition maintenance work.
齐鹏, 李永刚, 马明晗, 武玉才, 纪璇. 基于环流时频图谱的抽水蓄能机组励磁绕组匝间短路故障诊断[J]. 电工技术学报, 2023, 38(22): 6104-6120.
Qi Peng, Li Yonggang, Ma Minghan, Wu Yucai, Ji Xuan. Diagnosis of Inter-Turn Short Circuit in Excitation Winding of Pumped Storage Units Based on Time-Frequency Map of Circulating Current. Transactions of China Electrotechnical Society, 2023, 38(22): 6104-6120.
[1] 孙宇光, 王炳辉, 徐伟, 等. 发电电动机励磁绕组匝间短路故障在线监测[J]. 电力自动化设备, 2017, 37(3): 211-217. Sun Yuguang, Wang Binghui, Xu Wei, et al.Online monitoring of excitation winding inter-turn short circuit of generator/motor[J]. Electric Power Auto- mation Equipment, 2017, 37(3): 211-217. [2] 梁艳萍, 燕秀龙, 于鸿浩. 抽水蓄能电站发电电动机端部磁场及结构件损耗分析计算[J]. 电工技术学报, 2016, 31(6): 21-29. Liang Yanping, Yan Xiulong, Yu Honghao.Analysis and calculation of magnetic field and structure loss in end region of generator-motor for pumped storage power station[J]. Transactions of China Electro- technical Society, 2016, 31(6): 21-29. [3] Dirani H C, Merkhouf A, Giroux A M, et al.Impact of real air-gap nonuniformity on the electromagnetic forces of a large hydro-generator[J]. IEEE Transa- ctions on Industrial Electronics, 2018, 65(11): 8464-8475. [4] Shaikh M F, Park J, Lee S B.A non-intrusive leakage flux based method for detecting rotor faults in the starting transient of salient pole synchronous motors[J]. IEEE Transactions on Energy Conversion, 2021, 36(2): 1262-1270. [5] Dirani H C, Merkhouf A, Kedjar B, et al.Rotor interturn short circuit impact on large hydrogenerator magnetic quantities[J]. IEEE Transactions on Industry Applications, 2018, 54(4): 3702-3711. [6] 李永刚, 王罗, 李俊卿, 等. 基于多源信息融合的同步发电机转子绕组匝间短路故障识别[J]. 电力系统自动化, 2019, 43(16): 162-167, 191. Li Yonggang, Wang Luo, Li Junqing, et al.Identi- fication of inter-turn short-circuit fault in rotor windings of synchronous generator based on multi- source information fusion[J]. Automation of Electric Power Systems, 2019, 43(16): 162-167, 191. [7] 桂林, 陈俊, 王凯, 等. 基于柔性光学TA的发电电动机主保护优化设计[J]. 电力系统自动化, 2020, 44(18): 132-138. Gui Lin, Chen Jun, Wang Kai, et al.Optimal design of main protection for generator-motor based on flexible optical current transformer[J]. Automation of Electric Power Systems, 2020, 44(18): 132-138. [8] Zamudio-Ramirez I, Osornio-Rios R A, Antonino- Daviu J A, et al. Magnetic flux analysis for the condition monitoring of electric machines: a review[J]. IEEE Transactions on Industrial Infor- matics, 2022, 18(5): 2895-2908. [9] Ehya H, Nysveen A, Skreien T N.Performance evaluation of signal processing tools used for fault detection of hydrogenerators operating in noisy environments[J]. IEEE Transactions on Industry Applications, 2021, 57(4): 3654-3665. [10] Ma Minghan, He Pengkang, Li Yonggang, et al.Fault diagnosis method based on multi-source information fusion for weak interturn short circuit in synchronous condensers[J]. IET Electric Power Applications, 2021, 15(9): 1245-1260. [11] 孙宇光, 杜威, 桂林, 等. 用于多相无刷励磁机开路与短路故障检测的磁极探测线圈设计[J]. 电工技术学报, 2022, 37(14): 3542-3554. Sun Yuguang, Du Wei, Gui Lin, et al.Design of pole detection coils for open-circuit and short-circuit faults in multiphase brushless exciter[J]. Transactions of China Electrotechnical Society, 2022, 37(14): 3542-3554. [12] 魏东, 刘侃, 丁荣军, 等. 基于多重同步压缩变换的永磁同步电机初期匝间短路故障检测[J]. 电工技术学报, 2022, 37(18): 4651-4663. Wei Dong, Liu Kan, Ding Rongjun, et al.A multi-synchrosqueezing transformation based early stage detection of inter-turn short circuit fault in permanent magnet synchronous machine[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(18): 4651-4663. [13] 谢颖, 胡圣明, 陈鹏, 等. 永磁同步电机匝间短路故障温度场分析[J]. 电工技术学报, 2022, 37(2): 322-331. Xie Ying, Hu Shengming, Chen Peng, et al.Thermal field analysis on inter-turn short circuit fault of permanent magnet synchronous motor[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(2): 322-331. [14] 张业成, 刘国海, 陈前. 基于电流波动特征的永磁同步电机匝间短路与局部退磁故障分类诊断研究[J]. 电工技术学报, 2022, 37(7): 1634-1643, 1653. Zhang Yecheng, Liu Guohai, Chen Qian.Dis- crimination of interturn short-circuit and local demagnetization in permanent magnet synchronous motor based on current fluctuation characteristics[J]. Transactions of China Electrotechnical Society, 2022, 37(7): 1634-1643, 1653. [15] 赵方伟, 王秀和, 赵文良, 等. 内置式永磁同步电机动态偏心故障下的轴电压解析分析和削弱[J]. 电工技术学报, 2022, 37(4): 837-848. Zhao Fangwei, Wang Xiuhe, Zhao Wenliang, et al.Analysis and reduction of shaft voltage in interior permanent magnet synchronous motors under dynamic eccentricity fault[J]. Transactions of China Electrotechnical Society, 2022, 37(4): 837-848. [16] 朱洪雷. 水轮发电机磁极线圈匝间短路检查及处理[J]. 防爆电机, 2012, 47(3): 48-50. Zhu Honglei.Inspection and treatment of interturn short circuit of hydraulic turbine generator magnetic pole coils[J]. Explosion-Proof Electric Machine, 2012, 47(3): 48-50. [17] 李永刚, 王海蛟, 武玉才, 等. 基于交流阻抗法的发电机励磁绕组短路故障诊断[J]. 大电机技术, 2017(4): 10-14, 22. Li Yonggang, Wang Haijiao, Wu Yucai, et al.Field winding short circuit fault diagnosis on turbine generators based on the AC impedance test[J]. Large Electric Machine and Hydraulic Turbine, 2017(4): 10-14, 22. [18] 吕英, 金人文. 水轮发电机磁极线卷匝间短路的寻找和现场处理[J]. 水电站机电技术, 1985, 8(3): 47-51. Lü Ying, Jin Renwen.Finding and field treatment of turn-to-turn short circuit of magnetic pole wire of hydrogenerator[J]. Mechanical & Electrical Tech- nique of Hydropower Station, 1985, 8(3): 47-51. [19] 孙宇光, 余锡文, 魏锟, 等. 发电机绕组匝间故障检测的新型探测线圈[J]. 中国电机工程学报, 2014, 34(6): 917-924. Sun Yuguang, Yu Xiwen, Wei Kun, et al.A new type of search coil for detecting inter-turn faults in synchronous machines[J]. Proceedings of the CSEE, 2014, 34(6): 917-924. [20] Wu Yucai, Ma Qianqian, Cai Bochong.Fault diag- nosis of rotor winding inter-turn short circuit for sensorless synchronous generator through screw[J]. IET Electric Power Applications, 2017, 11(8): 1475-1482. [21] Cuevas M, Romary R, Lecointe J P, et al.Non- invasive detection of winding short-circuit faults in salient pole synchronous machine with squirrel-cage damper[J]. IEEE Transactions on Industry Appli- cations, 2018, 54(6): 5988-5997. [22] Ehya H, Nysveen A.Pattern recognition of interturn short circuit fault in a synchronous generator using magnetic flux[J]. IEEE Transactions on Industry Applications, 2021, 57(4): 3573-3581. [23] 郝亮亮, 吴俊勇, 孙宇光, 等. 同步发电机转子匝间短路故障监测方案及其灵敏性分析[J]. 电力系统自动化, 2013, 37(12): 120-127. Hao Liangliang, Wu Junyong, Sun Yuguang, et al.A monitoring scheme for inter-turn short circuit of field windings in synchronous machines and its sensitivity analysis[J]. Automation of Electric Power Systems, 2013, 37(12): 120-127. [24] Hao Liangliang, Sun Yuguang, Qiu Arui, et al.Steady-state calculation and online monitoring of interturn short circuit of field windings in syn- chronous machines[J]. IEEE Transactions on Energy Conversion, 2012, 27(1): 128-138. [25] 郭玉恒, 王思良, 任保瑞, 等. 二滩水轮发电机转子匝间短路故障的电气特征及在线监测[J]. 水电与抽水蓄能, 2018, 4(3): 9-15, 97. Guo Yuheng, Wang Siliang, Ren Baorui, et al.Electrical characteristics and on-line monitoring of rotor winding inter-turn short circuit fault of Ertan hydrogenerator[J]. Hydropower and Pumped Storage, 2018, 4(3): 9-15, 97. [26] 辛鹏, 戈宝军, 陶大军, 等. 多极隐极发电机励磁绕组匝间短路时的定子分支环流谐波特性[J]. 电工技术学报, 2017, 32(7): 67-76. Xin Peng, Ge Baojun, Tao Dajun, et al.Stator branch circulating current harmonic characteristics of multi- pole non-salient-pole generator with field winding inter-turn short circuits[J]. Transactions of China Electrotechnical Society, 2017, 32(7): 67-76. [27] 钱国超, 赵仲勇, 邹德旭, 等. 基于连续小波变换的变压器绕组变形故障类型检测[J]. 高电压技术, 2017, 43(6): 2016-2023. Qian Guochao, Zhao Zhongyong, Zou Dexu, et al.Detection of transformer winding deformation fault types based on continuous wavelet transform[J]. High Voltage Engineering, 2017, 43(6): 2016-2023.
2023, Vol. 38 
