基于全相位FFT三谱线校正的电网谐波与间谐波检测算法

电网谐波检测中，传统FFT算法存在的频谱泄露现象影响了检测的精度.为解决这一问题，分析和比较了全相位FFT算法与FFT算法之间的区别，将一种三谱线校正方法推广到精度更高的全相位FFT算法，并由此提出一种全相位FFT三谱线校正算法.该算法利用频谱峰值频点周围三根谱线信息构造频率偏移量修正公式，进而获得全相位FFT幅值和频率校正值，并利用全相位FFT的相位不变性直接获得信号相位.通过与FFT三谱线插值算法、全相位FFT双谱线校正算法和全相位FFT双谱线插值算法对比，结果表明该全相位算法具有更好的谐波和间谐波检测精度，并且抗白噪声能力更强.

Harmonic and interharmonic detection algorithm based on all-phase FFT triple spectrum line correction

In power grid harmonic detection， the spectrum leakage of traditional FFT algorithm affects the harmonic detection accuracy. To solve this problem， the differences between the all-phase FFT algorithm and the FFT algorithm are analyzed and compared， and a triple spectrum line correction method is extended to the all-phase FFT algorithm. And an all-phase FFT triple spectrum line correction algorithm is proposed. The algorithm uses the information of three spectral lines around the peak frequency point to construct the frequency offset correction formula to obtain the amplitude and frequency correction of the all-phase FFT.The phase invariance of all phase FFT is used to obtain the signal phase directly.Compared with the FFT triple spectrum line interpolation algorithm， the all-phase FFT double spectrum line correction algorithm and the all-phase FFT double spectrum line interpolation algorithm， the results show that the proposed algorithm has better detection accuracy of harmonics and inter-harmonics， and stronger anti-white noise ability.