基于多谱线插值法和复调制细化法的电力系统谐波分析

Harmonic analysis of power system based on multi-spectral interpolation and complex modulation

非同步采样时采用快速FFT会造成频谱泄露,为了降低频谱泄露的影响,提高谐波和间谐波检测精确度,提出了一种基于多谱线插值法和复调制细化法的组合分析方法。首先估算出基波和谐波的长范围泄露并将其消除,然后分析目标频点附近的几条谱线并利用谱线携带的信息,推导出多谱线的插值算法,并采用多项式拟合的方法得到其修正式。对于频率非常相近的电力系统信号,采用基于复解析带通滤波器的复调制细化法对其进行细化分析,得到其较精确的信号参数。仿真和实验结果验证了文中方法的有效性和高精度性。

In order to reduce the influence of spectrum leakage caused by non-synchronous sampling in FFT and improve the accuracy of harmonic detection between harmonics,a combined analysis method based on multi-spectral interpolation algorithm and improved complex modulation method is proposed in this paper.Firstly,the long-range leakage of fundamental and harmonics is estimated and removed,and then,the spectral lines around the target frequency are analyzed.The information of these spectral lines is fully used to derive the multi-spectral interpolation algorithm,and polynomial interpolation.Its modified formula is obtained through the fitting method.For the signals of power system with very close frequency,the detailed analysis is carried out on the basis of the complex modulation refinement method based on the complex analysis band-pass filter.Simulation and experimental results verify the effectiveness and accuracy of the proposed method.