Analysis of Acclerated aging Vegetable Oil and Mineral oil in Distributional Transformers

초록

Most of transformers use insulating and cooling fluids derived from petroleum crude oil, but mineral oil is some possibility of environmental pollution and fire with explosion. Vegetable oil fluids extracted from seed has superior biodegradation and fire-resistant properties including an exceptionally high fire point enhancing fire safety. In this study, it is aimed at the practicality of substituting vegetable oil for mineral oil in liquid insulation system of transformers. As a rise in coil winding temperature has a direct influence on transformer life time, it is important to evaluate the temperature rise of coil winding in vegetable oil in comparison with mineral oil. Four transformers for the test are designed with 10KVA, 13.2KV and one phase unit. The temperature is directly measured in insulating oil of these transformers with the two sorts of vegetable oil and mineral oil dielectric fluid respectively. Experiment for aging carry out two means. First means remained 120℃ that transformer of mineral oil were operated at 185% load. Second means is that insulating oils of two sorts of vegetables oil and mineral oil were aged by thermal cycles repeating from 30℃ to 120℃. For the heating, Transformers were operated at 185% load. For the cooling, cooling system was operated in the chamber. Samples were analyzed at 42, 63 and 93cycles. Analysis contents are dielectric strength, total acid value and water content. Mineral oils compared results of first means with results of second means. And compared two sort of vegetable oil respectively with mineral oil in second means.