The Analysis of Mechanical Vibrations and Acoustic Pressure Level οf a Transformer Model

Abstract

The paper presents the results of vibroacoustic investigations and the measurements of the acoustic pressure level (noise) of a transformer model. The measurements were taken at a full transformer load in two operation conditions: at a producer packeted core and at unpacketed core. Unpacketing consisted in loosing the screws pressing the particular core plates. Mechanical vibrations were registered and the acoustic pressure level was measured. The vibroacoustic analysis results are presented in the form of frequency spectra and the results of the acoustic analysis of the transformer under study are shown by determining corrected values of the acoustic pressure level and by a frequency analysis.

Frequency and Time-Frequency Analysis of Acoustic Cavitation Noise in Insulating Oils

“…An acoustic emission signal from working transformer can be used for monitoring of its condition and recognizing the form of partial discharges generated in insulating oil. That acoustic signal could generate some cavitation bubbles [5,6].…”

Time-Frequency Analysis of Mechanical Vibrations of the Dry Type Power Transformer Core

“…The legal regulations introduced and the market rules forced the existing power enterprises to increase their competitiveness, which is connected with a dynamic cutting of operational costs of the particular installations of the national electric power system. The ultimate and the most essential aim of such management policy is minimization of the electric energy price [1][2][3][4].…”

“…Nevertheless, the above-mentioned measurement methods enable identification of only the cases of extreme loosening of the elements of the active part. Currently, the internal in-(571) spection is the only and effective way of identification of the loosening of the core and windings but it is a rather complicated and costly procedure [2,5,7].…”

The Application of the Correlative Analysis and the Regression Function for Determining Correlations οf the Measurement Results of Acoustic Emission Generated by Partial Discharges

“…The paper describes the dependence between the changes of the voltage supplying the spark-gap modeling partial discharges (PDs) on indeterminate potential particles moving in insulation oil and the values of selected descriptors calculated for the amplitude spectrum of the acoustic emission (AE) pulses generated [1][2][3][4][5][6][7][8][9][10]. It is a simple type relation, which is characteristic of a unilateral influence of the cause, which is the voltage changes, on the result, which are the value changes of the descriptors under study.…”