Characteristics of Acoustic Emission Signals Generated by the Contacts of the Selector
A. Cichoń, S. Borucki, D. Wotzka and M. Szmajda
Faculty of Electrical Engineering, Automatic Control and Computer Science, Opole University of Technology, S. Mikołajczyka 5, 45-271 Opole, Poland
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An important part of electric power transformer is the on load tap changer which enables for voltage regulation in the network. Due to high level of failure frequency of these devices it is necessary to look for new diagnostic methods which enable for theirs technical state estimation under transformer normal operating condition. Presently at the Electric Power Institute at Opole University of Technology there are works in progress aspiring to determine the application possibility of the acoustic emission method for on load tap changer diagnosis. Results of scientifically-research works aiming to characterize the acoustic emission signals generated by a separated selector are presented in the paper. Measurements have been performed in a setup with a model of on load tap changer type VEL-110-27 from ELIN. Acoustic emission signals generated by the selector have been analyzed in detail. Analysis of the time-frequency components of signals generated by on load tap changer has been carried out with the short time Fourier transform: and continuous wavelet transform. Based on the comparison outcome of acoustic emission signals generated by the power changer and by the selector two measuring paths endowed with wide band contact transducers have been proposed for the practical application.
DOI: 10.12693/APhysPolA.122.804
PACS numbers: 52.80.-s, 43.28.Js