Simulação numérica do escoamento do óleo através da bobina de um transformador trifásico

Abstract

Due to the relevance of power transformers in electrical power systems, continuous improvements in their thermal performance, to extend their lifespan, are crucial. The longevity of the equipment is closely related to the degradation of the insulation paper, which deteriorates faster under high operating temperatures. In this context, this study presents a Computational Fluid Dynamics (CFD) model to determine the detailed distribution of internal temperatures in the windings of a power step-up transformer operating at the Governador Parigot de Souza Hydroelectric Power Plant in Antonina (PR). The developed model analyzes the oil flow through the coils, considering both mineral and vegetable oils, with different distributions of winding losses and various inlet flow rates, whose results were compared with data available in the literature. The obtained results were satisfactory, showing that the distribution of losses has a significant impact on the temperature profile of the transformer coils, and that vegetable oil exhibits better thermal performance for the same inlet flow rate compared to mineral oil. Thus, the proposed model proves to be a precise tool for analyzing the behavior and flow rate of oil through transformer coils, as well as for evaluating the impact of oil type on winding heat transfer. Furthermore, it can be used as a predictive model to estimate critical regions, supporting decision-making processes and the thermal design of new equipment. This approach promotes the improvement of thermal efficiency, thereby extending the lifespan of transformers.