微机继电保护中滤除衰减直流分量的算法研究

Study of filtering decaying DC component algorithm for microprocessor-based protection

全波傅氏算法是基于周期信号推导出来的,当采样信号中含有衰减直流分量时,将会产生误差。该文在全波傅氏算法的基础上,提出一种改进算法,仅增加一个采样点,通过两次非递归全波傅氏变换,消去衰减直流分量的影响。对微机保护中费机时的运算进行合理简化,以提高计算速度。仿真实验表明,改进算法具有消除衰减直流分量能力强,计算量小,速度快的特点。

The decaying DC component in the sampling signal will bring errors to the full-wave Fourier algorithm, which is derived with periodic signal. Based on the full-wave Fourier algorithm, an improved algorithm by adding only one sampling point with two fullwave Fourier algorithm transforms to eliminate the error caused by the decaying component is put forward. Furthermore, a simplified method is proposed to substitute the time-consuming calculation. The simulation results prove that the calculation of improved algorithm is simple and fast.