Acoustic Emission Analysis of Dry Distribution Transformers

This article primarily discusses the acoustic emission analysis method and its application in the contactless diagnostics of distribution transformers with resin dry insulation. Initially, the article outlines a measurement technique used to compare the acoustic emissions of two machines of the same type and power during their operation. A parabolic camera was employed to pinpoint the source of increased noise in the exposed transformer. This approach enables the analysis of the frequency spectrum, allowing for 3D observation of the transformer and identification of the highest noise levels and acoustic emissions. The latter part of the article details the methods for measuring and evaluating the instability and magnitude of acoustic emissions in dry transformers under laboratory conditions. The measurements were conducted using a noise measuring device equipped with a three-octave spectral filter, covering a frequency range of 100 to 10 000 Hz.