中文摘要：

为应用方便直观的电路方法进行双馈风电并网系统故障分析和短路计算,针对电网故障后转子侧变流器（rotor side converter,RSC）控制方式提出一种双馈风机（doubly-fed induction generator,DFIG）序网等值电路。故障后RSC不间断控制的运行方式下,DFIG定子短路电流中含有幅值稳定的工频正负序分量、2个衰减速度不同且频率接近工频的正序分量以及衰减直流分量。分别推导了各交流成分对应的序网等值电路,其中,稳定工频正序分量对应的等值电路可用等值电势及正序阻抗来表示;稳定工频负序分量对应的等值电路用无源的负序阻抗来表示;而衰减交流分量可用受控电流源来描述。利用所提DFIG等值电路,应用传统序网分析方法即可方便进行短路计算,不需仿真就能获得双馈风机并网系统中各处的短路电流。通过PSCAD仿真验证了所提等值电路和解析算法的有效性。

英文摘要：

To conduct fault analysis and short-circuit calculation for DFIG （doubly-fed induction generator）wind power system conveniently using equivalent circuit method, a sequence network circuit model of DFIG wind turbines with rotor side converter （RSC） control during faults is proposed in this paper. With uninterrupted RSC control, DFIG stator fault current contains a steady ac-component at power frequency, two transient ac-components decaying with different time constants near power frequency, and a damping dc-component. Equivalent sequence circuits for each ac-component are derived. It indicates that equivalent circuits for steady positive and negative sequence ac-components can be described as equivalent potential with a positive sequence reactance and a passive negative sequence reactance respectively, while equivalent circuit for transient ac-components can be described as two controlled current sources. Based on the proposed sequence circuit model, short-circuit current flowing in DFIG wind power system can be calculated analytically without need of simulation. The proposed PSCAD simulation. analytic method is validated with