一种完全滤除衰减直流分量的全波傅氏改进算法

An improved full-wave Fourier Algorithm for Completely Filtering Decaying DC Component

微机继电保护中全波傅氏算法是以采样信号是周期信号为基础推导出来的,当被采样的信号中含有衰减直流分量时,结果会产生很大的误差。该文研究得出一种算法,直接算出衰减直流分量初始值和衰减时间常数,从而构造出不含衰减直流分量的周期函数,这样在采样时便对信号进行了补偿,便可直接用全波傅氏算法对采样信号进行处理。由于该算法直接求出衰减直流分量,理论上该算法没有误差,而且该算法与其它算法相比不仅大大减小了计算量,而且提高了精度。

The full-wave Fourier algorithm in Microprocessor-based protection is based on the periodic sampled signal, when there is the decaying DC component in input signal, algorithm will have higher error. This paper finds an algorithm which calculate the initial value of the decaying DC component and the decay time constant directly, so as to create a pe- riodic function without the decaying DC component. The signal can be compensated when sampling, and then can use the full-wave Fourier algorithm to process the sampled signal directly. Since the algorithm calculates the decaying DC component directly, theoretically the algorithm has no error, and the algorithm greatly reduces the amount of computation, and improves the accuracy.