快速傅里叶变换和广义形态滤波器在抑制局部放电窄带干扰中的应用

根据局部放电信号和窄带干扰的差异，提出了一种基于快速傅里叶变换(fast Fourier transform，FFT)和广义形态滤波器抑制窄带干扰的新方法。首先利用FFT得到窄带干扰的离散谱线，再利用基于数学形态学原理构造的广义形态滤波器将局部放电信号中的干扰滤除，最后进行傅里叶逆变换和小阈值处理以提取局部放电信号。仿真和实测数据的处理结果表明，该方法通过选取合理的结构元素可在滤除干扰的同时保留局部放电信号特征，较好地解决了局部放电信号中窄带干扰滤除的难题。

Application of Fast Fourier Transform and Generalized Morphological Filter in Suppression of Narrow-Band Interference in Partial Discharge Signal

On the basis of the differences between partial discharge(PD) and narrow-band interference,a new fast Fourier transform(FFT) and generalized morphological filter method to suppress the narrow-band interference in PD signal is proposed.First,by use of FFT the discrete spectral lines are obtained;then using generalized filter based on the principle of mathematical morphology the interference in PD signal is filtrated;finally,the inverse Fourier transform and small threshold processing are conducted to extract PD signal.Processed results of data from simulation and measurement show that by means of choosing rational structural elements the feature of PD signal can be preserved while the interference in PD signal is filtrated by the proposed method,thus the difficult problem of filtrating narrow-band interference in PD signal is solved.