为了分析高压电气设备的局部放电信号,介绍了基于短时傅里叶变换(STFT)的时频分析方法及其重要性,并使用2种基于Matlab的方法仿真分析了局放信号。结果显示,基于trfstft方法的STFT时频分析可很好的给出局放信号的时频变化规律及其强度并从噪声中分离出局放信号。这提供了一种对含噪的模拟局放信号去噪处理的方法,可帮助有针对性地减少其危害,并进行目标识别和故障诊断。
In order to analyze the partial discharge signals of the high-voltage electrical equipment, the time-frequency analysis method based on Short Time Fourier Transform(STFT)is presented. Two analysis methods based on the Matlab software are used in the simulation of the PD signals. The results with white noise or not are analyzed. The simulation results show that the STFT time-frequency analysis based on the trfstft analysis method can well fit the change curve and intensity with time and frequency,moreover, it can also easily separate the PD signals from noise, and it provides the method and foundation for separating noise. Accordingly, It not only can lessen the harm of the PD signals, but also helps make target discrimination and fault diagnosis.