计及变压器和线路阻抗的双馈风力发电机转子侧阻抗建模研究  

Research on Rotor Side Impedance Modeling of DFIG Wind Turbine Considering Transformer and Line Impedance

作　　者：宋绍剑[1] 王铮 刘斌[1] 廖碧莲[1] 吴永谦 SONG Shaojian;WANG Zheng;LIU Bin;LIAO Bilian;WU Yongqian(School of Electrical Engineering,Guangxi University,Nanning 530004,Guangxi Zhuang Autonomous Region,China)

机构地区：[1]广西大学电气工程学院,广西壮族自治区南宁市530004

出　　处：《电网技术》2020年第4期1392-1399,共8页Power System Technology

摘　　要：双馈风力发电机(doubly-fed induction generator,DFIG)的阻抗模型是分析和抑制风力发电机并网振荡问题的有效手段之一。在实际工程中,DFIG机组通常通过Y/D升压变压器接入输电网,但是现有的阻抗模型仅考虑DFIG本身模型,而未考虑网侧变压器以及线路阻抗对模型的影响,影响稳定分析的准确度。为了更加准确地分析DFIG风机与电网的之间交互行为,采用谐波线性化的方法,建立了计及变压器和线路阻抗的DFIG转子侧的正负序阻抗模型。该模型不但包含了异步电机、转子侧变换器、锁相环(phase-locked loop,PLL)以及控制环路,同时在建模的过程中考虑了网侧的线路阻抗和变压器对模型的影响。然后,通过频域仿真分析锁相环、变压器以及电网线路阻抗等因素对转子侧的正负序阻抗模型的影响。最后,与时域仿真结果作对比,验证了阻抗模型的正确性。结果表明:并网变压器对DFIG转子侧的正序阻抗模型的相角特性影响较大,而对幅值特性影响较小;通过DFIG转子侧阻抗模型可以预测DFIG与电网阻抗交互作用潜在的并网谐振点。The impedance model of doubly-fed induction generator(DFIG) is an effective method to analyze and mitigate resonance problems in grid-connected DFIG wind turbine and AC grid. Usually, DFIG is connected to transmission grid through step-up Y/D transformer. However, current impedance model only considers the DFIG model itself, and does not consider the effects of grid-side transformer and line impedance on the model, thus influencing accuracy of stability analysis. In order to analyze the interaction between DFIG and AC grid, a positive-negative sequence impedance model on DFIG rotor side is established by means of harmonic linearization. The model not only includes asynchronous motor, rotor-side converter(RSC), phase-locked loop(PLL) and control loop, but also considers the line impedance of the grid side and the effect of the transformer on the model during modeling process. Then, the effects of phase-locked loop, transformer and grid line impedance on the positive-negative sequence impedance model of rotor side are analyzed with frequency domain simulation. Finally, compared with the simulation results in time domain, correctness of the impedance model is verified. The results show that the grid-connected transformer has great influence on the phase angle characteristics of the positive-sequence impedance model on the DFIG rotor side, but has little effect on amplitude characteristics. The potential grid-connected resonant points of the interaction between DFIG and grid impedance can be predicted with the DFIG rotor-side impedance model.

关 键 词：双馈风力发电机 网侧变压器 线路阻抗 谐波线性化 正负序阻抗模型 

分 类 号：TM721[电气工程—电力系统及自动化]