提出了一种基于波形相似度因子的双馈风电场送出线路单相接地保护方法。推导出电网故障下的风力发电机端口短路电流表达式，分析风电送出线路故障后故障电流的暂态特性。在此基础上，建立了风电送出系统的0模瞬时值模型。然后，利用区内外故障时模型差异特征构造0模电压波形相似度因子，进行故障定位。最后，通过仿真验证了该方法在各种单相接地故障情况下，均能正确识别区内外故障，不受过渡电阻和频率偏移影响。

A novel single-phase grounding fault protection scheme for outgoing transmission lines of doubly-fed wind farms based on waveform similarity factor is proposed. The short-circuit current expression of wind turbine port under grid fault is derived, and the characteristics of transient fault current after the faults on wind power outgoing transmission line are analyzed. On this basis, a zero-mode instantaneous model of the wind power outgoing transmission system is established. Then the zero-mode voltage similarity factor is constructed by using the characteristics of the model difference between the internal and external faults to locate the fault. Finally, the simulation verifies that this method can correctly identify the internal and external faults in various single-phase grounding fault conditions, and the result is not affected by fault resistance and current frequency deviation.