Analytical calculation model of eddy current loss of power transformer winding using method of images

Purpose This paper aims to present an efficient analytical model based on the mirror-image method with frequency-dependent current density correction, designed to address the trade-off between accuracy and efficiency in calculating harmonic losses in transformer windings. Design/methodology/approach A 2D analytical model incorporating the mirror-image method was developed to account for core effects, augmented by a frequency-dependent current density correction for skin and proximity effects. The model was validated against both 3D finite element method (FEM) simulations and experimental measurements, conducted on a three-phase and a single-phase transformer, respectively. Findings The proposed method achieves a maximum relative error of less than 10% in the calculation of winding eddy current losses compared to 3D-FEM, while reducing computation time by over 70 times. Experimental results confirm its accuracy across frequencies, with an average error below 7%. Originality/value This study presents a computationally efficient 2D analytical model that accurately captures complex frequency-dependent losses, which serves as a key component for fast physical field evaluation in transformer digital twins.