【摘要】 抑制周期性窄带干扰是局部放电(partial discharge,PD)在线检测中的关键技术。该文在仿真分析PD信号与窄带干扰在快速傅里叶变换(fast Fourier transform,FFT)功率谱中特点的基础上引入了局部峰点的概念,并定义了局部能量比,提出使用局部能量比预处理的FFT功率谱去噪方法,并详述了使用该方法抑制窄带干扰的具体步骤。将局部能量比的大小模糊化,采用模糊C-均值阈值法自适应提取局部能量比的阈值。仿真及实测信号的去噪效果表明,该方法对于窄带干扰具有较强的抑制能力。将该方法用于小波包功率谱的去噪,并与传统的小波包去噪效果比较,结果表明,FFT在抑制窄带干扰方面具有一定的优势。更多还原

【Abstract】 The suppression of narrow-band interference is one of the key techniques of on-line monitoring of partial discharge.In this paper,the different characteristics of fast Fourier transform(FFT) power spectrum between simulation PD signals and PD signals mixed with the narrow-band interference were analysed.The notion of partial peaks was brought in and partial energy ratio was defined.Thus,a method of suppressing narrow-band interference using partial energy ratio pretreatment was proposed,and the steps are also designed.Besides,the magnitude of partial energy ratio is fuzzified and the adaptive fuzzy C-mean threshold algorithm was proposed to extract the threshold of partial energy ratio.The denoising simulation shows that the proposed method could pick narrow-band interference signal from real PD signal.The method of this paper was used in wavelet packet power spectrum to denoise narrow-band interference,comparison with that of wavelet packet denoising shows that the FFT is superior in suppressing narrow-band interference.更多还原