基于凯塞窗的谐波检测算法

Harmonic Detection Algorithm Based on Kaiser Window

针对电力系统谐波检测中使用快速傅里叶变换分析方法,存在频谱泄露和非同步采样等带来较大误差的问题,文中提出凯塞窗的FFT和窗函数恢复系数减小幅度误差的谐波分析方法。通过仿真计算窗函数的幅度恢复系数,当信号加凯塞窗后进行FFT分析,可抑制频谱泄露,再乘以对应β值的窗函数幅度恢复系数,从而得到各次谐波的幅度值。仿真结果表明,利用含有20次的谐波信号,采用加窗FFT分析和幅度恢复的方法;当β=10时,凯塞窗的幅度误差低于三角窗、汉宁窗和布莱克曼窗;当β=30时,凯塞窗的谐波幅度误差小于4%。通过和其他窗函数以及不同β值的幅度误差比较,得出提高凯塞窗的β值,可减小谐波的幅度误差。

Aiming at the problems of large-scale error such as spectrum leakage and non-synchronous sampling use the method of the Fast Fourier Transform（ FFT） in the harmonic detection of power system,in this paper put forward the method Kaiser window with FFT and the way harmonic analysis of window function restoration coefficient for reducing amplitude error. The magnitude recovery coefficient of the window function is calculated by simulation,when the signal of Kaiser window analyzed by FFT can suppressed the spectral leakage and multiplied by the amplitude recovery coefficient of window function corresponding to value of β in order to get the amplitude value of each harmonic. The simulation results show that the method of window FFT analysis and amplitude recovery can be realized by using 20 harmonic signals,when β = 10,the amplitude error of Kaiser window is lower than that of triangular window,Hanning window and Blackman window; when β = 30,the harmonic amplitude error of Kaiser window is less than 4%. By comparing the magnitude error of others window functions and different β values,can reduced the amplitude error of harmonic by improved the β value of Kaiser window.