“…Comparative simplicity of the algorithms of computer implementation caused the use of schematic models in engineering calculations at the stage of design preparation of production [4,5]. However, a number of assumptions and simplifications, which laid the basis of schematic models, lead to deviations from the actual electromagnetic processes of energy conversion of AC during its transformations [8,9]. Simplified descriptions of surface effects, nonlinear properties of active and structural materials [10], disregarding the peculiarities of a multi-component spatial structure of the active part of transformers [11] can lead to significant calculation errors [12][13][14].…”