Measurement and Analysis of Acoustic Signal Generated by Partial Discharges in Insulation Oil

This paper described the measurement of acoustic signal generated by partial discharge in insulation oil and analysis of their frequency spectrum to acquire information for diagnosing oil insulated transformers. We designed a decoupler and a low-noise amplifier to detect acoustic signals with high sensitivity. Also, three types of electrode system; the needle-plane, the plane-plane, the wire-wire were assembled to simulate partial discharge in insulation oil. The frequency ranges of analyzed acoustic signal were 60 kHz~270 kHz for the needle-plane, 45 kHz~250 kHz for the plane-plane, and 50 kHz~180 kHz for the wire-wire electrode system. Their main frequencies were 145 kHz, 118 kHz and 121 kHz, respectively.