Diagnostics of power transformers cores using a modified vibroacoustic method

• Main Authors: Borucki, S., Boczar, T., Fracz, P., Zmarzły, D.
• Format: Conference Proceeding
• Language: English
• Subjects: acceleration; core; diagnostics; Frequency measurement; Oil insulation; power spectrum density; power transformer; Power transformer insulation; Transformer cores; vibration; Vibration measurement; Vibrations; vibroacoustic method
• ISSN: 1089-084X
• DOI: 10.1109/ELINSL.2012.6251453

The paper presents research results referring to the development of a non-invasive method of assessment of the power transformer core technical condition based on the analysis of the registered mechanical vibrations. It characterizes the power unit under study, the measuring system used and the developed methodology of assessment of the core pressing degree using the vibroacoustic method. The original results of the time-frequency analysis of the vibroacoustic signals presented in the paper were obtained during switching on a real 630 kVA dry type power transformer under laboratory conditions. The analysis of the signals registered was carried out for three states of its operation: the core pressed by the manufacturer, the core with loose screws fixing the upper yoke and the core with separated upper yoke beams. The method proposed by authors, the so-called modified vibroacoustic method, is based on the mechanical vibrations measurements of an appliance under study in its transient state - while switching on the unit. The research work aims at developing a modern and, what is most important, non-invasive assessment method of the core technical conditions of power transformers operating in the national electric power system.