不同类型短路故障下双馈风机短路电流分析

Analysis for Short Circuit Current of DFIG-based Wind Generation System Under Different Types of Short Circuit

研究风电机组的短路电流特性是分析风电机组并网后电网短路电流变化的前提。基于双馈感应发电机DFIG(doubly fed induction generato)r的Park模型及定转子磁链守恒原理推导了机端三相短路下计及撬棒(Crowba)r保护的DFIG短路电流解析表达式。根据该表达式分析了DFIG短路电流特性,并从定子和转子衰减常数的角度分析可能影响短路电流的因素。利用DIgSILENT/PowerFactory仿真软件建立并网运行的DFIG单机模型,对理论分析的正确性进行了验证,还通过仿真分析了不对称短路下DFIG的短路电流特性,为进一步全面研究DFIG的短路电流特性提供参考。

Researching the characteristics of short circuit current of DFIG is the base of analyzing the short circuit current of power grid after connecting DFIG to grid.The approximate expression of short circuit current of DFIG considering Crowbar protection under three phase short circuit located at generator terminal is derived based on Park model of DFIG and the principle of flux conservation.Then the characteristics of short circuit current of DFIG and the factors that may affect it were analyzed based on this expression and the attenuation constant of stator and rotor.A single generator connected to grid model of DFIG was built by using DIgSILENT/PowerFactory.The simulation results demonstrated the correctness of theory analysis.In addition,the short circuit of DFIG under unsymmetrical short circuit was also simulated to provide the reference for further research.