الفهرس | Only 14 pages are availabe for public view |
Abstract Condition assessment of transformer oil is crucial in examining the oil quality, enabling reliable operation of the transformer. There are various methods for condition assessment of transformer oil. Among these methods, optical spectroscopy emerged as a dependable and efficient methods In this thesis, the condition of rical and thermal stresses was evaluated using photoluminescence (PL) and ultraviolet-visible (UV-Vis) spectroscopies, with a primary focus on electrical stresses. Thermal aging is performed using accelerated aging at 120 °C so that one day under an accelerated aging test is equivalent to approximately one year in the field. On the other hand, two types of electrical aging are applied. The first type is electrical aging due to arcing by subjecting transformer oil samples to successive impulsive discharges, while the second type is partial discharge aging using a custom-built test cell with six needles to accelerate the aging process. Different aging extentsare used to prepare the oil samples that were electrically and thermally aged. Then, PL and UV-Vis spectra are obtained for oil samples that had been aged electrically and thermally. All obtained spectra are compared in terms of intensity and wavelength. Finally, the corresponding physical mechanisms behind the obtained spectra are discussed and clarified. |