【摘要】 风机的弱惯性使其在送出线故障后易引发较大频率波动，导致基于工频的傅氏算法产生测量误差，严重影响电流保护的可靠性。首先理论分析送出线故障工况下直驱风机频率变化的原因及其动态变化特性，然后根据傅氏算法测算电流基波幅值的计算方法，分析直驱风机频率变化对电流保护的影响，最后建立直驱风机并网仿真模型，结合风电场送出线实际保护配置，系统地分析了不同故障类型、不同故障位置、不同线路长度情况下电流保护动作特性。研究表明：送出线故障下直驱风机频率发生动态变化且变化幅度较大；随着频率的增大，傅氏算法测算的电流幅值减小，导致电流保护Ⅰ段的保护范围缩小，降低了电流保护的灵敏度。本研究为含高比例新能源电网的保护整定与优化提供了理论依据。更多还原

【Abstract】 Due to the weak inertia of wind turbine, it is easy to cause large frequency fluctuation after the fault of the outgoing line,resulting in the measurement error of Fourier algorithm based on power frequency, which seriously affects the reliability of current protection. Firstly, the reasons for the frequency change of direct-drive wind turbine and its dynamic characteristics under the fault condition of the outgoing line are analyzed theoretically, and then the influence of the frequency change of direct-drive wind turbine on the current protection is analyzed according to the calculation method that calculates the amplitude of current fundamental wave based on Fourier algorithm. Finally, the grid connected simulation model of direct-drive wind turbine is established. Combined with the actual protection configuration of the outgoing line in the wind farm, the operation characteristics of current protection under different fault types, different fault locations and different line lengths are systematically analyzed. The research shows that the frequency of direct-drive wind turbine changes dynamically and greatly under the fault of outgoing line. With the increase of frequency, the current amplitude measured by Fourier algorithm decreases, which leads to the reduction of the protection range of section I of current protection and reduces the sensitivity of current protection. This study provides a theoretical basis for the protection setting and optimization of power grid with high proportion of new energy.更多还原