Research on Calculating Eddy-Current Losses in Power Transformer Tank Walls Using Finite-Element Method Combined With Analytical Method

An improved analysis method to calculate the eddy-current losses in large power transformer tank walls is presented. In this model, the perpendicular magnetic flux density has been obtained at discrete points on the surface of the tank by the finite-element method (FEM). A double Fourier series is adopted to express the obtained magnetic flux density by analytical formulas. The coefficients of the analytical expressions are determined by a least mean error with a curve fitting technique and an optimization algorithm. Based on the electromagnetic theory and the Maxwell equations, the eddy-current losses are obtained by the analytical formulas. The validation of this method is verified by TEAM Problem 21 (Model B). The calculation results are in good agreement with the measured results. Then, it could be extended to calculate the eddy-current losses in the metal structural parts of the power transformer.