风电场常用等值方法的适用性及其改进研究

Applicability and Improvement of Common-Used Equivalent Methods for Wind Farms

为分析定速机组风电场常用等值方法的适用性,以电磁暂态仿真软件PSCAD/EMTDC为分析平台,搭建了定速机组风电场详细模型和等值模型。通过比较风速波动情况下和故障情况下的风电场等值模型与详细模型的并网点输出特性,对2种常用等值方法的适用性进行了分析。结果表明,当风电场风速差异较大时,等值模型会出现一定的误差:风速波动下等值模型会出现无功功率误差;故障下等值模型的误差与故障前风速、故障持续时间有关。定性分析了风电场等值模型的误差产生原因,指出风电场常用等值方法与分类方法相结合可大大提高风电场动态等值方法的适用性。

To analyze the applicability of common-used equivalent methods for wind farms, using electromagnetic transient analysis software PSCAD/EMTDC as the platform the detailed model and equivalent model of wind farm composed by fixed speed wind turbines are built. Through the comparison of output characteristics of the detailed model and equivalent model of wind farm at the grid-connected point under wind speed fluctuation and fault condition, the explicabilities of the two common-used equivalent methods are analyzed. Analysis results show that the equivalent model may cause a certain error while the wind speed differences among wind turbines are evident; the equivalent model may lead to reactive power error under fluctuation of wind speed; the error of equivalent model under fault is relative to the wind speed before fault and the duration of fault. The reasons leading to the error of equivalent wind farm models are qualitatively analyzed, and it is pointed out that integrating common-used equivalent methods for wind farms with classification methods the applicability of dynamic equivalent method for wind farms can be greatly improved.