中文摘要：

为抑制局部放电在线监测中的周期性窄带干扰，在分析局部放电信号与周期性窄带干扰的小波功率谱特点基础上，发现多频混合周期性窄带干扰会在小波功率谱的不同位置产生幅值很大的干扰功率峰。为此，提出一种基于小波功率谱抑制混频周期性窄带干扰的方法，阐述利用小波功率谱抑制混频周期性窄带干扰的基本原理和步骤：同时对经典的阈值法作了改进，采用K-均值阈值算法来改进阈值法对窄带干扰频率的自适应性。仿真结果表明，该方法具有较好的

英文摘要：

In order to suppress the periodic narrow-band noise in the partial discharge （PD） on-line monitoring system, the different characteristics between PD signals and the narrow-band noise with respect to wavelet power spectrum were analyzed, it was found that the huge interfering power peak of the narrow-band noise with mixed frequencies appears in the wavelet power spectrum. Thus, a new method to suppress above noise was put forward based on this discovery, and the basic principles and process of applying this de-noise method were expounded. Besides, the K-mean threshold algorithm originated in classic threshold methods was taken to improve the self-adapting ability of this de-noise method with regard to the frequency of narrow-band noise with mixed frequencies. Simulation results show that the proposed method in this paper has fine self-adapting ability and strong narrow-band noise-suppressing capacity.