THERMAL SCIENCE

International Scientific Journal

Safaa Ismael Al-Musawi

,

Zoran M. Lazarević

,

Radovan R. Radosavljević

,

Zijad M. Bajramović

,

Predrag V. Osmokrović

THE OIL - PAPER INSULATION RELIABILITY ESTIMATION OF 420 KV TRANSFORMER CONCERNING THERMAL STRESSES DURING EXPLOITATION CONDITIONS

ABSTRACT
The calculating of reached ageing based on the history of loading according of International Electrotechnical Commission standard algorithm is the first task. In order to verify the obtained results, measurements of polymerization index were made on 28 paper samples taken directly from low voltage terminals (winding ends) and bus connections of the transformer under test rated 380 MVA, 2´15,75 kV/420 kV. The complete procedure of paper sample locations and taking off is described, thereby providing a manner of how this should be done, determined by specific conditions of the transformer under test. Furthermore, the determination of limit viscosity and using its relationship function with polymerization index are explained together. Comparison is made with those of liquid chromatography of oil. The results of particle sort and size analysis are shown. Finally, an estimation of the transformer life remainder is made, which is of paramount importance when defining the steps that have to be made either in revitalization process or in transformer replacement planning.
KEYWORDS
generator transformer, thermal stress, solid insulation, ageing, life estimation, polymerization index
PAPER SUBMITTED: 2015-04-09
PAPER REVISED: 2016-01-09
PAPER ACCEPTED: 2016-01-13
PUBLISHED ONLINE: 2016-01-30
DOI REFERENCE: https://doi.org/10.2298/TSCI150409003A
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2016, VOLUME 20, ISSUE Issue 5, PAGES [1713 - 1723]
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The oil - paper insulation reliability estimation of 420 kV transformer concerning thermal stresses during exploitation conditions

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence