Abstract: The paper presents the most recent results of an advance experimental research in the area of cooling and ageing processes taking place in large power transformers in oil-paper insulation. It is broadly accepted that the life of a power transformer is the life of the oil/ paper insulating system, also the fact that most failures in their final on electro-mechanical base such as a short temperature increment or a mechanical failure. During the natural ageing of transformers, the insulation of winding, which is cellulose paper, deteriorates. Cellulose insulation degrades due to heating or electrical Breakdown, resulting in the production of furfural derivatives, which dissolve in oil. Hence, the chemical analysis of the Transformer oil gives evidence of changes that are taking Place in the winding insulation during operating. Deterioration in transformer cellulose decreases both its electrical and mechanical strength. The “Rule of 6” (based upon the Arrhenius Equation of chemical reaction time v/s temperature) can be adapted to approximate the relationship between insulation life and total operating temperature. This rule states that if a transformer’s maximum operating temperature is reduced by 6°C, the thermal life of the insulation system is approximately doubled. Conversely, if the total operating temperature is raised by 6°C, the thermal life expectancy of the insulation system is reduced by one half. The goal of this discussion is to use all necessary measures to prevent the inevitable shortening of the traditionally expected life-time of 40 years in newer transformer and discussion to increase some year of transformer life.
Keywords: Transformer lifetime, OFAFWF cooling, insulation ageing, temperature, water coolant.
Title: Advance Cooling Technique of Large Power Transformer and Impacts of Cooling On the Age of Transformer
Author: Manmohan Prajapati, A. Pachori
International Journal of Electrical and Electronics Research
ISSN 2348-6988 (online)
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