电晕放电电磁辐射信号的双谱估计与时频分析

研究电晕放电辐射信号的时频特性,对于电气设备的故障诊断、在线监测以及辐射源定位等都有重要意义。笔者利用Hinich法和ADF法对电晕放电电磁辐射信号的高斯性、线性和平稳性进行了定量分析和检验,结果显示此类信号具有非高斯性、非线性和非平稳性。在此基础上,通过双谱估计和时频分析方法研究了电晕放电辐射信号的时频域特征,结果表明:放电辐射信号的持续时间较短,其频率主要分布在较高频段,分布范围较宽,能量主要集中在400~800 MHz范围内,与背景噪声信号的时频域特征有明显区别,有利于对信号进行特征提取和目标识别。

Bispectrum Estimation and Time-frequency Analysis of Electromagnetic Signal Radiated from Corona Discharge

The Hinich test and ADF test are used to quantitatively analyze and test the signal radiated from corona discharge,and the results show that such a signal is non-Gaussian,non-linear and non-stable.Subsequently,the characteristics of the signal in both time domain and frequency domain are investigated by using bispectrum estimation and time-frequency analysis.The results are as follows: the signal’s waveform in time-domain has oscillation form with double exponential attenuation and shorter duration;its frequency components mainly distribute in higher frequency band with a wide range,and the discharge energy concentrates in the frequency band of 400~800 MHz;the characteristics of the signal in time domain and frequency domain are obviously different from that of noise,which is of benefit to signal feature extraction and target recognition.