The study of acoustic emission method for detection of partial discharge in power transformer

Six kinds of typical oil gaps were designed and tested to simulate partial discharges (PD) in the insulation of power transformers. The frequency spectra of acoustic emission (AE) of PD in those gaps were presented and investigated with a computer-aided measuring system. The attenuation of AE and the variation of its frequency spectrum in oil and in oil-impregnated paper were studied. Peak frequencies in the frequency spectra of AE of PD in these gaps were distributed in the 70-150-kHz range. Based on test results, the frequency bandwidth of 70-180 kHz was recommended for the AE measuring system of PD detection in power transformers.<>