计及撬棒投切的双馈风电机组精细化整定计算等值模型

Precise DFIG equivalent model for setting calculation based on activated stage and deactivated stage of Crowbar protection

目前在双馈风电机组(DFIG)的等值模型研究中尚未建立简单、精确的模型,无法满足整定计算建模的要求,为此提出了计及撬棒投切的精细化DFIG整定计算等值模型。首先对网侧变流器的影响进行分析,建立了相应的等值模型;随后通过对DFIG的状态空间方程以及转子侧变流器无功控制方程求解,给出定子短路电流的表达式。在此基础上结合整定计算建模的特点,对定子输出短路电流进行分解,得到了撬棒投入阶段和切除阶段的DFIG等值模型。撬棒投入阶段模型可用于主保护阶段整定计算建模,切除阶段则可用于后备保护阶段的建模。最后通过仿真验证了等值模型的正确性。

Simple and accurate model has not been established in current equivalent model research of DFIG(Doubly-Fed Induction Generator),which cannot meet the requirement of setting calculation and modeling.In order to solve this problem,a precise DFIG equivalent model for setting calculation based on activated stage and deactivated stage of Crowbar protection is proposed.Firstly,the influence of GSC(Grid-Side Con⁃verter)is analyzed,and the corresponding equivalent model is established.Then the expression of stator short circuit current is obtained by solving the state space equation of DFIG and reactive power control equation of RSC(Rotor-Side Converter).Based on this,combining the characteristic of setting calculation model,the stator short circuit current is decomposed,and then the DFIG equivalent models of Crowbar in activated stage and deactivated stage are obtained.The DFIG model of Crowbar in activated stage can be used for setting calculation of main protection,while the model in deactivated stage can be used for setting calculation of backup protection.Finally,simulative results verify the correctness of the equivalent model.