Devising a method for large-scale modeling of non-stationary electromagnetic processes in power transformer equipment under sharply changing loads

This study considers the sharply changing loads on powerful transformers and the non-stationary electromagnetic processes they excite, consisting of a set of parameters of different physical nature. The task addressed relates to the fact that powerful transformers used in modern electrical technologies fail almost twice as often as those operating in public networks. This encourages the design of special-purpose transformer equipment and requires establishing causal factors of accidents, their development, and new research methods. This work reports a method for large-scale modeling of non-stationary electromagnetic processes in transformers. The proposed criteria for the physical similarity of electromagnetic processes in the model and the original have been confirmed experimentally on a physical model and a real special-purpose transformer. A distinctive feature of the results is a method devised for the formation of sharply changing currents, which are characteristic of the electro-technological process in arc steelmaking furnaces. The results of investigating additional losses and thermal overload of the transformer coincide, with reasonable accuracy for practice, with the experimental ones with an error not exceeding 5.7%. This makes it possible to compile project documentation for designing new types of special-purpose transformers. This is achieved by improving engineering methods for calculating additional losses and thermal overloads of inactive parts of transformer structures. In practice, the results allow for the correction of acceptance tests both at the design stages and under industrial conditions