Calculation of Winding Eddy Losses in Converter Transformers Based on IEC 61387:1-2011 Formulations and FEM

To ensure safety, sustainability and efficiency, the effect of harmonic currents on transformers should be calculated and evaluated at the design stage. Harmonic currents increase eddy current losses in transformer windings. The magnetic field in which the transformer windings are located has radial and axial components. These components generate radial and axial eddy losses. When a transformer is loaded with harmonic currents, eddy losses occur depending on the magnetic field and frequency generated by those currents. The IEC 61387-1:2011 standard can be used to calculate these losses. In this context, it is necessary to calculate the radial and axial components of the eddy losses in the transformer. In this study, winding eddy loss calculations are performed according to different approaches on a transformer. For this purpose, the finite element method is used to calculate the axial and radial fields in the windings. In addition to these, eddy loss calculations were performed directly with the finite element method.

The effect of harmonic spectrum on winding eddy losses is analyzed and the results of different approaches are evaluated. Accordingly, this work highlights the significance of adapting loss calculations for transformers subjected to harmonic currents.