消除暂态过程影响的滤波算法及其在故障测距中的应用

电力系统故障暂态过程中,电压、电流信号包含着衰减直流等暂态分量,这必然对故障暂态过程电气量的获取精度产生影响.通过构建精确求解基频及整次谐波分量的非线性方程以及将其转化为线性方程进行求解,并针对离散化积分引入的误差进行修正,提出一种能完全滤除衰减直流分量的高精度、高稳定的滤波算法.通过对各种典型信号及幅频特性的分析,验证了该算法计算精度高、稳定性好,且对非整次谐波等故障暂态分量具有较强的抗干扰能力和抑制作用,其在故障测距中的应用表明该算法能有效提高故障暂态过程中的测距精度.

A Filtering Algorithm for Eliminating Effect of Transient Component and Its Application on Fault Location

During the fault transient process,the accurate extraction of power-frequency components is affected by the decaying dc and other transient components existing in the transient voltage and current signals.This paper proposes a novel filtering algorithm to extract the accurate fundamental and integer harmonic frequency component by means of a set of linear equations,which is transformed from a non-linear equation representing the error in discrete Fourier transform affected by decaying dc.Meanwhile,by analyzing the discrete integral error,a correctional scheme is proposed.Extractions from several typical signals and analysis of the frequency response characteristics prove that the proposed algorithm is accurate and stable and has the anti-interference ability for non-integer harmonic frequency component.Extensive tests of fault location show that the algorithm can efficiently improve the precision of fault location during the transient process.