ON SOME COMPARISON BETWEEN ACCELERATED AGING OF MINERAL OIL UNDER HIGH ELECTRIC FIELD AND HIGH TEMPERATURE
DOI:
https://doi.org/10.36801/Keywords:
ACCELERATED AGING, MINERAL OIL, HIGH ELECTRIC FIELD, HIGH TEMPERATUREAbstract
During the operation of electric power transformers, their insulation often made from paper and mineral oil is subjected to thermal, mechanical, and electrical stresses. Therefore, the lifetime of power transformers can be assimilated with their insulation system lifetime. The aim of this paper is to explore and present the main degradation aspects for mineral oil, subjected to the action of high electrical field and partial discharge and exposure to thermal stress exclusively, analyzing and pointing out changes in the dielectric properties. Thus, the obtained results indicate that both the thermal and, especially, the electrical stresses produce important variations of the values of the real and imaginary part of the complex relative permittivity, the electrical conductivity, and the loss factor which indicates a severe oil degradation.
References
(1) H. Zainuddin, "Transformer Oil Ageing Detection using Mach–Zender Interferometry Configuration as a Sensor", Int. J. of Recent Technology and Engineering, vol. 8, no. 26, pp. 826-831, 2019.
(2) A. Ciuriuc, M.S. Vihacencu, L.M. Dumitran, P.V. Noţingher, “Comparative Study on Power Transformer Vegetable and Mineral Oil Ageing”, Anals of the University of Craiova, no. 36, pp. 46-51, 2012.
(3) M. Martins, A. Gomes, "Comparative study of the thermal degradation of synthetic and natural esters and mineral oil: effect of oil type in the thermal degradation of insulating kraft paper", IEEE Electrical Insulation Magazine, vol. 28, no. 2, pp. 22-28, 2012.
(4) M. Yea, K. Han, J. Park, S. Lee, J. Choi, "Design optimization for the insulation of HVDC converter transformers under composite electric stresses", IEEE Transactions on Dielectrics and Electrical Insulation, vol. 25, no. 1, pp. 253-262, 2018. DOI: 10.1109/tdei.2018.006629.
(5) J. Kúdelčík, L. Varačka, E. Jahoda, S. Poljak, "Post-breakdown stages in transformer oil", The European Physical Journal Applied Physics, vol. 78, no. 2, pp. 208-213, 2017.
(6) J. Tanaka, "Free Radicals in Electrical Insulation", in Proceedings of the 19th Symposium of Electrical Insulating Materials", Osaka, Japan, 1986.
(7) I. Lingvay, V. Stănoi, L. Ungureanu, F. Șerban, A. Borș, "Gases forming during thermal ageing of some electrical use oils", Electrotehnica, Electronica, Automatica, vol. 65, no. 2, pp. 23-30, 2017.
(8) I. Fofana, J. Sabau, D. Bussieres, E. Robertson, "The Mechanism of Gassing in Power Transformer’", in Proceedings of the IEEE Int. Conf. on Dielectric Liquids (ICDL’80), 2008, pp. 1-4.
(9) I. Fofana, A. Bouaicha, M. Farzaneh, J. Sabau, „Ageing Behavior of Mineral and Ester Liquids: A Comparative Study”, 2008 Annual Report Conference on Electrical Insulation Dielectric Phenomena (CEIDP), Quebec, 26-29 October 2008, pp. 87-90.
(10) T.V. Oommen, “Vegetable Oils for Liquid-Filled Transformers”, IEEE Electrical Insulation Magazine, Vol. 18, No. 1, January/February 2002, pp. 6-11.
(11) A. Ciuriuc, “Degradation and lifetime estimation of vegetable oil for power transformer”, PhD Thesis, University Politehnica of Bucharest, 2015.
(12) W. Zaengl, "Dielectric spectroscopy in time and frequency domain for HV power equipment. I. Theoretical considerations", IEEE Electrical Insulation Magazine, vol. 19, no. 5, pp. 5-19, 2003.
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