Insulating and thermal aging dielectric properties dependency of transformer oil using spectroscopy techniques

Power transformers are of the key and the most expensive devices used in electrical power transmission systems. Maintenance is essential in increasing the life time of these devices [1]. Degradation and aging of the insulation is recognized as one of the major causes of transformer breakdowns [2]. Characterization and analysis of the dielectric fluid quality level are used to ensure the proper functioning of the insulation [3-5]. This helps understanding the causes of possible internal defects [1, 6]. The purpose of this study is to investigate on service-aged oil transformers as well as on oil aged ones in laboratory conditions. Accelerated thermal and chemical aging procedures were performed in the laboratory [7]. IDA 200 was used to evaluate the frequency scan of insulation material properties. The dissipation factor, conductivity, real, imaginary part of permittivity, were measured as function of the temperature and the frequency. Through this study, it was found that despite the approximation of test conditions, the results obtained for these samples are different. However, the results indicate that the accelerated aging in the laboratory conditions does not really reflect the state of the oil. © 2019 Lavoisier. All rights reserved.