针对基于声发射技术的绝缘子污秽放电在线监测系统采集到的声信号容易受到背景噪声的干扰进而难以捕捉放电初期的微弱放电脉冲问题,探讨了数学形态学滤波在绝缘子污秽放电声发射信号降噪研究上的应用.从放电信息完整性的角度分析了背景噪声干扰下绝缘子污秽放电声发射信号的微弱放电脉冲的提取方法,运用Top-Hat变换和边缘检测阈值相结合的方法对含噪的污秽放电信号进行处理.研究结果表明该方法能在完整保留信号特征的同时有效地抑制信号中的噪声,且实时性较高,适用于在线监测系统. Acoustical signals collected by on-line monitoring system of insulator fouling discharge based on acoustic emission technology are easily disturbed by background noise and difficult to capture the weak discharge pulse at the beginning of discharge. Mathematical morphology filtering is also used to study the noise reduction of acoustic emission signal of insulator fouling discharge On the basis of the information integrity of the discharge, the method of extracting the weak discharge pulse of the acoustic emission signal from the insulator discharge under the background noise interference is analyzed. The combination of the Top-Hat transform and the edge detection threshold is applied to the noise- Signal.The results show that the proposed method can effectively preserve the signal characteristics while effectively suppressing the noise in the signal and has high real-time performance and is suitable for on-line monitoring system.