局部放电监测中现场干扰的分析与抑制

局部放电在线监测的关键是如何有效简便地抑制各种干扰，但目前对现场干扰的研究多限于定性分析。本文利用数字滤波方法对现场干扰作了定性分析和定量研究，对目前研究较多的ＬＭＳ（最小均方误差）自适应滤波、ＦＦＴ（快速傅立叶变换）阈值滤波的效果作了对比分析，指出它们在实际应用中尚存在不足，并且提出了一种基于ＦＦＴ的理想多带通数字滤波器。应用于现场的数据处理，该方法具有处理简单、抑制比高、意义明确等优点，是抑制连续周期性干扰的较好措施。对于脉冲干扰，提出了一种新的利用脉冲信号波形特征进行逻辑判断的脉冲识别方法，取得了较好的效果。

Analysis and rejection of interference in on line partial discharge monitoring

The main problem in on line partial discharge monitoring is how to reject the interference. At the present, the main focus is placed on the qualitative analysis of interference. In this paper, several digital filters are used to analyze the field interference both in quality and quantity, including LMS (Least Mean Square) Adaptive Digital Filter, FFT (Fast Fourier Transformation) Threshold Digital Filter. The study is also made on these digital filters and some deficiencies related to these methods are pointed out. Also in this paper, a new Ideal Multi bandpass Digital Filter based on FFT is used to process the data sampled in field tests, which has the advantages of simple operation, high rejection ratio and clear meaning and is regarded as a good method for rejecting the continuous periodic interference. As to pulse interference, a method of pulse identification is raised based on the logical judgement of the features of pulses and a good result is got.