基于加窗插值FFT算法的间谐波检测方法研究

电网中间谐波的存在,会对电能质量以及供电可靠性带来不利影响,故准确检测间谐波对电力系统稳定运行意义重大。根据间谐波特性,在一般FFT算法基础上,提出了基于加窗插值FFT算法的间谐波检测方法。通过分析对比不同窗函数的特点,选取检测精度较高的Hanning窗作为所加分析窗,同时确定所加窗函数的宽度及采样周期,可准确检测出系统中的谐波及间谐波。在MATLAB环境下仿真得到一般FFT算法及加窗插值FFT算法对谐波和间谐波的检测结果,通过对所得频率和幅值估计结果的对比分析可知,加窗插值FFT算法检测精度更高、实用性更强。

Research on Inter-harmonic Detection Using Windows and Interpolated FFT Algorithm

The inter-harmonics in power grid may cause negative influence on power quality and power supply reliability,so the accurate detecting of inter-harmonics is important for the stable operation of the power system.According to the inter-harmonics characteristics,based on the FFT algorithm,interpolation FFT algorithm was proposed to detect inter-harmonics.Through the analysis of the characteristics of different window functions,Hanning window is selected as the analysis window,and the window-length and the sampling period are determined,which can detect harmonics and inter-harmonics accurately.Besides,FFT algorithm and interpolation FFT algorithm are simulated by MATLAB.By contrasting and analyzing the estimated results of frequency and amplitude,it can be seen that the windows and interpolated FFT algorithm can detect harmonics and inter-harmonics of a given signal much more accurately.