Abstract:Considering the limitations of existing transformer harmonic models at home and abroad, a modeling method for establishing harmonic transformer model based on practical measurement is proposed in this paper. The influence of harmonics on short-circuit impedance parameters and the nonlinearity of the core are studied. By conducing the transformer harmonic short-circuit test, the impedance frequency variation expression of the winding from 0 to 2450Hz is fitted and realized by a Foster circuit. By conducting the transformer harmonic open-circuit test, the effects of frequency, phase and peak of harmonic voltage on the excitation characteristics of the transformer are studied, and a simplified modeling method of the excitation branch based on the “maximum flux linkage method” is proposed. The modeling method is implemented to the process of modeling a practical transformer. The results show that the obtained model can not only describe the frequency variation characteristics of the winding under harmonic conditions, but also characterize the nonlinear characteristics of the iron core. What’s more, the established model can be used to calculate transformer loss with a high level of accuracy. This modeling method has the characteristics of high accuracy and meets the needs of engineering practical applications.
[1] 崔恒斌, 冯晓云, 林轩, 等. 车网耦合下高速铁路牵引网谐波谐振特性研究[J]. 电工技术学报, 2013, 28(9): 54-64. [2] 周毅, 胡海涛, 杨孝伟, 等. 电气化铁路车网耦合系统低频振荡分析[J]. 中国电机工程学报, 2017, 37(增刊1): 72-80. [3] Martinez J A, Mork B A.Transformer modeling for low-and mid-frequency transients-a review[J]. IEEE Transactions on Power Delivery, 2005, 20(2): 1625-1632. [4] Amoiralis E I, Tsili M A, Kladas A G.Transformer design and optimization: a literature survey[J]. IEEE Transactions on Power Delivery, 2009, 24(4): 1999-2024. [5] Chowdhury A H, Grady W M, Fuchs E F.An investigation of the harmonic characteristics of transformer excitation current under nonsinusoidal supply voltage[J]. IEEE Transactions on Power Delivery, 1999, 14(2): 450-458. [6] Greene J D, Gross C A.Nonlinear modeling of transformers[J]. IEEE Transactions on Industry Appli- cations, 1988, 24(3): 434-438. [7] 李慧奇, 李晓孟, 李金忠, 等. 计及铁心损耗和磁滞效应改进的变压器模型[J]. 电工技术学报, 2016, 31(21): 196-202. [8] 张重远, 王增超, 张欣, 等. 基于改进矢量匹配法的变压器铁心频变涡流模型[J]. 高电压技术, 2015, 41(5): 1618-1623. [9] 刘书铭, 施红, 冯蕾. 考虑集肤效应与邻近效应的变压器谐波损耗模型[J]. 电力自动化设备, 2015, 35(3): 133-139. [10] De Leon F, Semlyen A.Time domain modeling of eddy current effects for transformer transients[J]. IEEE Transactions on Power Delivery, 1993, 8(1): 271-280. [11] Avila-Rosales J, Alvarado F L.Nonlinear frequency dependent transformer model for electromagnetic transient studies in power systems[J]. IEEE Transa- ctions on Power Apparatus and Systems, 1982(11): 4281-4288. [12] Yildirim D, Fuchs E F.Measured transformer derating and comparison with harmonic loss factor (F/sub HL/) approach[J]. IEEE Transactions on Power Delivery, 2000, 15(1): 186-191. [13] Galli A W, Cox M D.Temperature rise of small oil- filled distribution transformers supplying nonsinu- soidal load currents[J]. IEEE Transactions on Power Delivery, 1996, 11(1): 283-291. [14] Yildirim D, Fuchs E F.Computer-aided measurement of inductor losses at high frequencies (0 to 6kHz)[C]// APEC'99: Fourteenth Annual Applied Power Elec- tronics Conference and Exposition, Conference Pro- ceedings, 1999: 1203-1209. [15] 尹忠东, 魏文思, 王萍, 等. 考虑集肤效应和邻近效应的变压器绕组谐波损耗计算及实验研究[J]. 电力系统保护与控制, 2019, 47(4): 143-151. [16] Fuchs E F, Lin D S, Martynaitis J.Measurement of three-phase transformer derating and reactive power demand under nonlinear loading conditions[J]. IEEE Transactions on Power Delivery, 2006, 21(2): 665-672. [17] Song Kejian, Konstantinou G, Wu Mingli, et al.Windowed SHE-PWM of interleaved Four-Quadrant converters for resonance suppression in traction power supply systems[J]. IEEE Transactions on Power Electronics, 2017, 32(10): 7870-7881. [18] Semlyen A, Deri A.Time domain modelling of frequency dependent three-phase transmission line impedance[J]. IEEE Transactions on Power Apparatus and Systems, 1985(6): 1549-1555. [19] Baghzouz Y, Gong X D.Voltage-dependent model for teaching transformer core nonlinearity[J]. IEEE Transactions on Power Systems, 1993, 8(2): 746-752.