高压绝缘子污秽放电声信号的时频特性分析

Time-Frequency Characteristic Analysis of Acoustic Signal for Insulator Contaminant Discharge

绝缘子发生污秽放电时的声信号中含有大量能够体现绝缘子污秽程度的信息量,利用傅里叶变换(FFT)将声信号分解为时域和频域两部分,研究在不同污秽度下声信号的时频特性,发现声信号的时域的平均值和频域的频谱特性两方面含有4个特征量,这4个特征量充分体现了绝缘子污秽放电的发展特征。分析得出,声信号时域的均值、最大值、标准差及FFT实部幅值这4个特征量与绝缘子污秽度具有很好的关联性,但是4个特征值对污秽预测结果的影响不尽相同。试验结果表明,绝缘子污秽放电声信号的4个特征量可以作为新的污闪预警特征量。

The acoustic signal, occurs when insulator contaminant discharge, contains a large number of information which can reflect the contaminated degree of insulator. Based on EFT conversion, the acoustic signal is decomposed into two parts ： time domain and frequency domain. The acoustic signal time-frequency characteristics under different pollution degree are studied, it is found that the average value of the time domain and the frequency spectrum characteristics contain four characteristic values, which reflect the development characteristics of insulator contaminant discharge. The analyzed results show that, the typical value , maximum and standard deviation, and the real part of amplitude, four characteristic values have a good correlation with contamination degree, but the influence of the four characteristic values on contamination forecast result is different. Experimental results show that these four characteristic values can be used to prediction contamination degree of insulators effectively, and provide new characteristics for the contamination pre-warning.