On-line evaluation of power transformer temperatures using magnetic and thermodynamics numerical modeling

The power transformer heating should be monitored in order to avoid ageing of the insulation of impregnated paper and - consequently - the transformer's premature depreciation. This work describes the development and implementation of a thermal model aiming to calculate the internal temperatures in power transformers using numerical simulations to obtain an online model to estimate the hotspot temperatures. In order to validate the proposed procedure, a comparison with direct measurement in the power transformer is performed.