不同撬棒保护投入时刻下双馈风电机组短路电流计算分析

双馈感应风电机组故障特性不同于传统同步电机，对电网继电保护的整定与配合产生不利影响，需从解析的角度揭示双馈感应风电机组的故障暂态机理。以双馈感应发电机空间矢量模型为基础，结合电路动态响应理论，建立了双馈风电机组三相短路电流解析计算模型。所建模型考虑了定、转子电阻的影响，从理论上证明了衰减时间常数的由来及与频率分量的对应关系。考虑到控制作用的影响，撬棒的投入会有延时，解析模型计及了不同的撬棒保护投入时刻。与仿真和现场试验结果对比验证了所建模型的准确性，并从仿真角度分析了转子电压、双馈风电机组运行状态及转子侧控制策略对故障电流的影响。最后运用解析模型定量评估了定转子电阻、短路发生时刻及DFIG的运行工况等因素对短路电流的影响。

Calculation and analysis of three-phase short-circuit current of doubly fed wind turbine considering different crowbar protection insertion time

Doubly fed induction generator (DFIG) has a different fault characteristic when compared to traditional synchronous generator, and it has negative impacts on relay protection setting and cooperation, thus revealing the fault mechanism of DFIG from the point of analysis is an important issue. Based on vector model of DFIG, superposing the steady state and fault state, combined with the dynamic response circuit theory, and considering the different crowbar protection insertion time, a model for calculating the three-phase short-circuit current of DFIG is established. The analytical model takes into account the influence of the stator and rotor resistance, theoretically proving the origin of the decay time constant and corresponding relationship with the frequency component. The simulation results validate the model. Finally the paper quantitatively assesses the impacts of the degree of voltage dips, short-circuit occurred time and operation condition of DFIG on the short-circuit current.