In the first, introductory chapter, the transformer was mentioned as the main element of this thesis. The aim of the thesis and the division into chapters are explained too. The second chapter is theoretical and contains a description of the transformer and its characteristics, including its nominal values. In the continuation of the second chapter, as part of the short-circuit and no-load operating states, the experiments during these operating states, which were preformed in the next chapter, are explained. The third chapter is the practical part of the thesis, in which a total of 4 measurements were made in 2 operating states of the transformer: short-circuit and no-load state of the transformer in positive and zero sequence. From those 4 measurements, 4 tables with results were obtained, which in the fourth chapter will be used for modeling that three-phase two-winding transformer in the EMTP – RV software package. The entire modeling process in the software package EMTP – RV of the three-phase two-winding transformer on which the measurements were preformed is described in the fourth chapter. In each of the subchapters, it is explained how the user windows should be filled within the elements of the scheme representing the basic characteristics of the transformer, the transverse branch and the saturation of the transformer. The final, fifth chapter contains the conclusion of the thesis.