基于CZT的电力谐波参数高精度估计

A new method with high accuracy for electrical harmonic estimation based on CZT

提出了一种基于CZT的电力系统谐波参数高精度估计方法。利用CZT实现频谱细化的特点,首先从复杂信号中提取基波分量,将其减去。然后对剩余信号加5项Rife-Vincent窗,进行FFT分析。最后根据提取基波频率求出各次谐波频率,对Rife-Vincent窗函数在频域插值。仿真验证表明5项Rife-Vincent窗抑制频谱泄露效果很好,在非同步采样的情况下,对含有30次谐波的复杂信号进行仿真分析,结果与传统双谱线插值算法有几乎相同的估计精度,但计算时间约节省了一半。

A new method with high accuracy for electrical harmonic estimation based on CZT（Chirp z-transform） is presented in this paper.First,using the characteristic that CZT can realise frequency spectrum refinement,the phasor of the power system fundamental frequency signals is extracted from the multifrequency signals.After subtracting the system fundamental frequency signal from the multifrequency signals,the surplus signal is truncated with the five term Rife-Vincent window and its spectrums are calculated by FFT.Finally,according to the power system fundamental frequency,each harmonic frequency is calculated.And then the Rife-Vincent window is interpolated in the frequency domain.The results of experiments show that the five term Rife-Vincent window has a better curb ability to the spectral leakage.And in the non-coherent sampling conditions,the proposed method almost has the same estimation accuracy with the method which is based on multipoint interpolation FFT through analysing the 30 order harmonics,but the new method only costs about half computation times.