关于双馈风电场动态等值的认识和探讨

以双馈风电机组为例,对不同风速下机组的暂态响应特性进行了模拟分析,发现和解析了一些有意义的现象,并以此为基础对双馈风电场动态等值的相关问题进行了研究和探讨。研究表明:低风速机组在暂态过程中存在明显的有功消耗现象,使其在风电场动态等值中不宜忽略;工作于不同风速下的风电机组,其有功功率和电流暂态响应曲线在幅值大小、波动程度及响应速度方面呈现出非线性差异,导致分群数多但等值效果可能变差;工作于恒转速区和恒功率区的风电机组,其有功功率和电流暂态响应曲线的聚群特性,使其可以合为一群;大型风电场集电线路较长且接线复杂,基于功率损耗相等原则得到的等值阻抗,不能保证暂态过程中的一致性,因此应加强集电网络阻抗动态特性方面的研究。

Views and Discussions on Dynamic Equivalent of DFIG Wind Farms

This paper takes the doubly fed induction generator(DFIG)wind turbine as an example to simulate and analyze the transient response characteristics of a wind turbine under different wind speeds condition. Some issues related to dynamic equivalent modeling of wind farms are discussed with intensive investigations. Firstly, the wind turbines working on low wind speed are found to consume a large amount of active power during the transient process not to br ignored casually for dynamic modeling of wind farms. Secondly, more clusters may have poorer equivalent accuracy, since the transient current and active power curves of the wind turbines working on different wind speeds show nonlinear differences in amplitude, fluctuations and transient response time. Thirdly, the wind turbines working in constant-rotor-speed and constant-power zones can get clustered to a single equivalent wind turbine since their transient active power and current curves are similar to each other. Finally, for a large wind farm with long collector lines and complicated configurations, the equivalent network impedance calculated by the equivalent power loss rule is not able to guarantee the consistency of wind farm outputs between the detailed and equivalent models during the transient process. So, studies about the dynamic characteristics of the collector network impedance should be emphasized. This work is supported by National Natural Science Foundation of China(No. 51377034), China Southern Power Grid Company Limited(No. CSGTRC-K142002)and Heilongjiang Provincial Natural Science Foundation of China(No. E201432).