改善电力系统谐波分析的加窗插值算法和递推傅氏算法

Window functions, interpolation and Fourier transform recursive algorithm for improving the harmonic analysis of power system

傅里叶变换进行电力系统谐波分析时很难做到同步采样和整周期截断,由此造成的频谱泄漏将影响谐波分析的效果;通过加窗和插值可以改善谐波分析的准确度。采用基于两根谱线的加权平均来修正幅值的算法,利用多项式逼近的方法得到频率和幅值的修正公式;同时,提出了用傅里叶递推算法来改善谐波分析的实时性。仿真结果验证了算法的有效性和可行性。

There are difficulties in performing synchronized sampling and integral period truncation in the harmonic analysis of power system with the Fourier transform technique, and the measuring results will be disturbed by the frequency leakage. The utilization of window functions and interpolation algorithms can improve the accuracy of harmonic analysis. An improved algorithm is introduced in this paper, with which the frequency and amplitude of harmonic can be estimated. The polynomial approximation method is employed to obtain simple formulae for frequency and amplitude correction. In order to improving real-time performance, recursive algorithm of Fourier transform is presented. The simulation results have verified the effectiveness and feasibility of the algorithms.