Degradation diagnosis of solid insulation using sound waves emitted by partial discharge

Insulation degradation diagnoses by measuring partial discharges (PD) has been studied actively. The most important task in the study is development of new PD measuring methods where diagnostic accuracy is improved. One of these methods is the acoustic emission (AE) measuring method. By taking notice of the sound waves emitted by a PD, we are studying the relationship with the signals of sound waves and the insulation degradation in the case of using polyethylene terephthalate (PET). This paper confirms that sound waves are emitted by PD in PET and shows that the power spectrum of the measured sound waves is transformed to the frequency domain by a fast Fourier transform (FFT).<>