N2 - On-load tap changers (OLTC) are some of the main transformer elements that make voltage adjustment in a power network possible. Their failures often cause shutdowns of distribution transformers. The paper presents research work aimed at the assessment of the technical condition of OLTCs by the acoustic emission method (EA). This method makes the OLTC diagnosis possible without the need of disconnecting the transformer from the system. The measurements were taken in laboratory conditions. The influence on the operation non-concurrence of the power tap changer contacts on the AE registered signals has been investigated. The signals registered were subjected to analyses in the time and time-frequency domains. The result analysis in the time domain was carried out using the Hilbert transform and calculating characteristic times for the particular runs. A short-time Fourier transform was used for the assessment of results in the time-frequency domain. L1 - http://www.czasopisma.pan.pl/Content/104448/PDF/09_paper.pdf L2 - http://www.czasopisma.pan.pl/Content/104448 PY - 2011 IS - No 4 EP - 830 DO - 10.2478/v10168-011-0054-4 KW - power transformer KW - on-load tap changers KW - acoustic emission method A1 - CichoĊ„, Andrzej A1 - Borucki, Sebastian A1 - Boczar, Tomasz PB - Polish Academy of Sciences, Institute of Fundamental Technological Research, Committee on Acoustics VL - vol. 36 DA - 2011 T1 - Diagnosis of the Non-Concurrent Operation of the On-Load Tap Changer Contacts by the Acoustic Emission Method SP - 823 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/104448 T2 - Archives of Acoustics