小波变换与傅里叶变换应用于电力谐波检测中的理论研究

Theoretical Research on the Application of Wavelet Transform and Fourier Transform in the Detection of Power Harmonics

电力系统中存在大量谐波,且谐波检测难度较大。因此,在现有研究的基础上对其展开理论研究,并提出了一种联合检测方法:首先对信号按频率进行分解,低频部分通过FFT法确定各次谐波含量。高频部分通过小波变换法分解和处理,并通过小波变换获得信号谐振发生时间点和谐振幅值大小,同时将高频部分中的噪声信号滤掉,最后对分解并处理后的信号进行重构。所设计的方案能够有效提高谐波频域检测和分析的精确度。进一步仿真表明,提出的谐波检测方案能够满足测量各次谐波含有率标准的要求。

There were a lot of harmonics in the power system,and harmonic detection was difficult,so on the basis of the existing research,theoretical research was carried out and a joint detection method was proposed.The signal was decomposed according to the frequency,and the content of each harmonic in the low frequency part was determined by FFT,the high frequency part was decomposed and processed by wavelet transform,and the time point and amplitude value of signal resonance were obtained by wavelet transform,at the same time,the noise signal in the high frequency part was filtered out.Finally,the decomposed and processed signals were reconstructed,the designed scheme could effectively improve the accuracy of harmonic frequency detection and analysis.Further simulation showed that the proposed harmonic detection scheme could meet the requirements of each harmonic content standard.