Abstract：Considering the limitations of existing transformer harmonic models at home and abroad, a modeling method for establishing harmonic transformer model based on practical measurement is proposed in this paper. The influence of harmonics on short-circuit impedance parameters and the nonlinearity of the core are studied. By conducing the transformer harmonic short-circuit test, the impedance frequency variation expression of the winding from 0 to 2450Hz is fitted and realized by a Foster circuit. By conducting the transformer harmonic open-circuit test, the effects of frequency, phase and peak of harmonic voltage on the excitation characteristics of the transformer are studied, and a simplified modeling method of the excitation branch based on the “maximum flux linkage method” is proposed. The modeling method is implemented to the process of modeling a practical transformer. The results show that the obtained model can not only describe the frequency variation characteristics of the winding under harmonic conditions, but also characterize the nonlinear characteristics of the iron core. What’s more, the established model can be used to calculate transformer loss with a high level of accuracy. This modeling method has the characteristics of high accuracy and meets the needs of engineering practical applications.
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2020, Vol. 21 
