声信号的频域分析方法及其在电气绝缘无损检测中的应用

FREQUENCY DOMAIN ANALYZING METHOD OF ACOUSTIC SIGNALS AND ITS APPLICATION IN NON DESTRUCTIVE TEST OF ELECTRICAL INSULATION

随着电压等级的不断提高，绝缘系统中的缺陷对整个电力系统的危害越来越大．为了寻找一种准确、简单和可靠的绝缘检测方法，研究了绝缘体在外力作用下产生声信号的频域特征，采用了瞬时平均功率、峰值频率、加权特征频率和平均功率谱等参数来描述绝缘体的内部结构特征。

With the increase of operating voltage of power system, the reliability of insulation system which depends on the defects within insulation becomes more and more important. It is necessary to investigate an accurate, simple and reliable method for defect defection and insulation diagnosis. In this paper, the frequency characteristics of forced vibration of insulation generator stator winding are studied. In order to use frequency domain analysis for our investigation, instantaneous mean power, frequency of peak and weighted frequency etc. are studied to describe the structure feature of insulation system. The authors propose a representation used for model identification of insulation defects, i.e.area function. Our investigation shows that frequency domain analysis is an effective method to detect the defects within insulations.