基于DTFT无窗函数电力系统间谐波检测高精度算法研究

Research on High-precision Algorithm of Power System Inter-harmonic Detection Based on DTFT of Real Number Field

由于电力信号频率波动,导致离散时间傅里叶变换(DTFT)存在频谱泄露和栅栏效应等问题,影响间谐波检测精度。传统算法利用加窗函数抑制频谱泄露,并做插值计算解决栅栏效应问题。根据实数域频谱特点和插值算法基本原理,分别构造实数频谱三谱线插值算法和六谱线插值算法,其中六谱线插值算法利用谱线叠加可以实现抑制频谱泄露。通过算例分析,对频率检测结果表明提出的算法检测精度高,其中实数域六谱线插值算法误差比传统算法减小一个数量级;对间谐波幅值检测结果表明实数域六谱线插值检测精度较高,且精度可以通过参数进行调节。

Due to the frequency fluctuation of electric power signal,the discrete time Fourier transform(DTFT)has the problems of spectrum leakage and fence effect,which will affect the detection precision of inter-harmonics.The traditional algorithm suppresses spectrum leakage by window-adding function,and solves the problem of fence effect by interpolation.In this paper,according to the characteristics of real number field spectrum and the basic principle of interpolation algorithm,triple-spectrum-line interpolation algorithm and six-spectrum-line interpolation algorithm are constructed respectively.The six-spectrum-line interpolation algorithm can suppress spectrum leakage by using spectral line superposition.Through the example analysis,the frequency detection results show that the proposed algorithm has high detection precision,and the errors of the six-spectrum-line interpolation algorithm in real number is one order of magnitude smaller than the traditional algorithm.The detection results of inter-harmonic amplitude show that the detection precision of six-spectrum-line interpolation in real number field is higher and the precision can be adjusted by parameters.