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Abstract：
The transient characteristics of wind farms in groups are quite different; in addition, there is a strong coupling between the wind farms and the grid, and these factors make the fault analysis of the grid with wind farm groups complicated. In order to solve this problem, a mathematical model of the converter is established based on the input-output external characteristics of the converter, and a transient model of a doubly fed wind turbine (DFIG) is presented considering the influence of the low-voltage ride-through control (LVRT) of the converter, and the effect mechanism of the LVRT strategy on the short-circuit current is analyzed. Finally, a short-circuit current calculation model of a doubly fed wind turbine with low-voltage crossing control is established. The interaction mechanism between wind farms during the fault is analyzed, and a short-circuit current calculation method of doubly fed wind farm groups is proposed. RTDS is used to verify the accuracy of the proposed short-circuit current calculation method for doubly fed field groups. On this basis, a method of power grid fault analysis after doubly fed field group access is discussed and analyzed.
摘要：
群风电场的暂态特性差异较大；此外，风电场和电网之间有很强的耦合，这些因素使得含风电场群的电网故障分析变得复杂。为了解决这个问题,根据变换器的输入输出外特性,建立了变换器的数学模型,考虑到变流器的低电压穿越控制(LVRT)的影响，提出了双馈风力发电机(DFIG)的暂态模型，分析了LVRT策略对短路电流的影响机理。最后,建立了低压穿越控制双馈风力发电机的短路电流计算模型。分析了故障期间风电场之间的相互作用机理,提出了双馈风电场群短路电流的计算方法。RTDS用于验证所提出的双馈磁场组短路电流计算方法的准确性。在此基础上,讨论并分析了双馈现场群接入后的电网故障分析方法。
