基于DFT滑窗迭代算法与小波变换的谐波检测方法

Harmonic Detection Based on Sliding-windows Iterative of Discrete Fourier Transform and Wavelet Transform

为解决非线性负载大量使用所产生的谐波电流对电力系统所造成的影响,提出了将DFT(Discrete Fourier Transform)滑窗迭代算法和小波变换相结合的谐波检测新方法。该方法利用滑窗迭代检测出信号的基波分量和总谐波分量,提高系统的实时性和目标跟随特性;然后利用小波变换对总谐波信号进行再次分解,对DFT滑窗迭代算法进行补充与改善,从而得到更加精确的基波和各次谐波的含量。利用MATLAB进行实验仿真表明,较之傅里叶变换和DFT滑窗迭代算法,该算法具有更高的实时性和准确性。

For solving the effect of harmonic current formed by non-liner loads in power system,the method based on combined sliding-windows iterative of discrete fourier transform（SWIDFT） and wavelet transform（WT） is proposed in this paper.The first step is to use SWIDFT to obtain the fundament component and total harmonic component,which improves the system′s real-time and tracing characteristic.The total harmonic component was decomposed once again using WT,making the detection results more accurate and giving a supplement and improvement to SWIDFT.The simulation result with MATLAB shows that the detection of frequency and amplitude based on SWIDFT and WT reached a more reasonable real-time and accuracy than FFT and SWIDFT.