Study of the Stray Losses Calculation in Structural Parts for HVDC Converter Transformers Based on the TEAM Problem 21 Family

The stray losses calculation method proposed by the IEC 61378-2 standard is analyzed in this study. The fundamental stray losses in different currents and the harmonic stray losses of the TEAM Problem 21 Family members are analyzed to verify the IEC method. It is shown that stray losses are approximately proportional to the square of the current, but do not follow the frequency to the power of 0.8. The IEC method typically produces large errors. A corrected calculation method is thus proposed in this study, in which the magnetic-field distribution is considered. The corrected method is verified in comparison with experimental results and the IEC method.