Application of Wavelet Analysis to Acoustic Emission Pulses Generated by Electrical Discharges in Air
نویسنده
چکیده
The subject matter of this paper refers to the improvement of the acoustic emission (AE) method when used for detection, measurement and location of electrical discharges in air insulation systems of power appliances. The detailed subject matter refers to the issues connected with the application of modern methods of digital processing of signals obtained during technical high-power measurements. The paper presents the results of measurements and time-frequency analyses of the AE pulses generated by electrical discharges in the pointplane system in air. The AE pulses measured were subject to the wavelet analysis. For electrical discharges the continuous wavelet transform (CWT) was determined and the corresponding time-frequency distributions were drawn. Moreover, for the AE pulses generated by electrical discharges the discrete wavelet transform (DWT) was calculated, the runs of the particular details for seven frequency levels and the approximation run were presented. In reference to the DWT analysis for the particular details, the probability density functions (PDF) and the autocorrelation functions (ACF) were determined at the particular levels of decomposition. Also columnar diagrams showing the energy value that is transferred at the particular levels of decomposition were presented. Moreover, the energy density spectrum runs determined through a Fast Fourier Transform (FFT) were presented for comparison. The Morlet wavelet was used to determine the CWT, and the symlet wavelet was used to calculate the DWT. The acoustic pulses generated by electrical discharges in both positive and negative half-times of the voltage supplying the sparkgap under study were analyzed
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تاریخ انتشار 2003