继电保护傅氏算法中滤除直流分量的一种简便算法

快速傅里叶变换（FFT）是电力系统进行谐波分析的主要算法，但当输入信号中含有衰减直流分量时，FFT算法会产生较大的误差。文中提出一种改进算法，能够在事先未知衰减常数的情况下，对衰减直流分量进行补偿，从而消除直流分量对基波及各次谐波幅值和相位的影响。该算法只需要在整周期采样的基础上增加一个采样点，理论上可以精确补偿衰减直流分量的影响，精度高、计算简单，适用于电力系统谐波分析中的精确算法。

A COMPACT ALGORITHM FOR FILTERING DECAYING DC COMPONENT IN RELAY PROTECTION FOURIER ALGORITHM

Fast Fourier transform (FFT) is the main algorithm for harmonic analysis in electric power system, but when there is the decaying DC component in input signal, FFT algorithm will have higher error. This paper proposes an improved algorithm, which can compensate the decaying DC component without knowing the decaying constant and eliminate the influence of decaying DC component on the fundamental frequency component and each harmonic. The new algorithm only needs to add one sample on the basis of the all wave sampling method, and can accurately compensate the DC component theoretically. It is simple and accurate, and is suitable for using as the accurate algorithm of the harmonic analysis in electric power system.