汉宁双窗全相位FFT三谱线插值检测谐波算法

Harmonic Detection Algorithm Based on Three-spectrum-line Interpolation of Double Hanning Windows All-phase FFT

在非同步采样情况下,利用快速傅里叶变换(FFT)进行电力系统谐波分析时,会带来频谱泄漏现象和栅栏效应,影响了信号的量测精度。为此,提出了一种汉宁双窗全相位FFT三谱线插值检测谐波算法。该算法原理是:在汉宁双窗全相位FFT分析的基础上,利用基波频点附近的3条相邻谱线幅值作比,计算出频率校正量,并由此估计出谐波信号的幅值;然后,结合全相位FFT分析的相位不变性,将采样点处幅值最大的谱线相位作为信号的初相。仿真实验表明,与其他插值算法相比,该算法可以更有效地降低谐波参数检测误差,减少白噪声干扰的影响。

Harmonic analysis of power systems based on fast Fourier transformation(FFT)produces spectrum leakage and fence effect in non-synchronous sampling,which brings errors to harmonic parameter measurement.To solve this problem,a harmonic detection algorithm based on double Hanning windows all-phase FFT three-spectrum-line interpolation is proposed.The principle of the algorithm is that based on the analysis of double Hanning windows all-phase FFT analysis,the frequency correction is calculated by comparing the three adjacent spectral line amplitudes near the fundamental frequency points and the amplitude of harmonic signal is estimated.And then,based on the invariance of all-phase FFT analysis,the phase of the main spectral line with the largest amplitude at the sampling point is used as the initial phase of the harmonic signal.The simulation experiment shows that compared with other interpolation algorithms,the algorithm can reduce harmonic parameter detection errors more effectively and has strong anti-white noise interference ability.