An AC loss model for Bi2223 superconductors in partial core transformers

This paper presents a modelling technique for calculating the ac losses for a high temperature superconducting partial core transformer using Bi2223 superconducting tape. The model is a function of the current in the tape and the magnetic field of the transformer. A time harmonic, two dimensional, finite element analysis of the transformer was used to determine the magnetic field in the winding area. This analysis showed that there was significant radial flux in the end winding regions, resulting in an elliptical nature of the magnetic field. The major and minor axes of the ellipse were used in the ac loss model. The AC losses modelled were compared with measured data from a sample HTS partial core transformer.