基于实测数据的双馈风电机组外特性研究及简化建模

基于机理建模的双馈风电机组模型复杂，且未考虑电压跌落期间变流器控制策略的改变，难以分析双馈机组电压跌落对系统暂态稳定的影响。双馈风电机组机端电压跌落过程持续时间较短，机组的输出主要受变流器控制策略的影响，不同双馈机组的外特性存在较大差异。由于变流器在电压跌落期间的控制策略为企业机密，一般难以获取，给机理建模带来较大的障碍。非机理建模根据输出的外特性构建简化双馈机组的暂态模型，避免了双馈机组建模的复杂性。对比两种1.5 MW双馈机组电压跌落的实测数据，分析机组的输出特性，并据此构建了双馈机组在电压跌落和恢复过程的简化等值模型。在PSASP软件中利用自定义建模，构建简化模型，进行仿真对比，和测试机组的实际输出具有较高的符合度。基于风电机组外特性的简化模型降低了模型的复杂度，适用于分析双馈风电机组电压跌落对系统暂态稳定的影响。

Research on external characteristics of DFIG and simplified modeling based on testing data

The DFIG model based on mechanism modelling is complex, and does not consider the change of converter control strategy in voltage dip period. It is not suitable to analyze how DFIG voltage dip impacts power system transient stability. Usually, the during time of DFIG terminal voltage dip is short. The output of wind turbine generator is mostly affected by converter control strategy. Different DFIGs have different external characteristics. It is hard to get converter control strategy of DFIG, as it is a secret of a company. Mechanism modeling may face this trouble. Non-mechanism modeling constructs simplified DFIG model based on external characteristics. This paper contrasts testing data of two 1.5 MW DFIGs and analyzes output characteristics in voltage sag process. Simplified equivalent model is constructed both for voltage dip and recovery. The simplified model is constructed in PSASP software and compared to testing wind turbine. They have similar output curves. It shows that simple model is suitable for analyzing the effect of DFIG voltage dip on transient stability of power system.