Divchuk T. The improvement of determination methods of no-load parameters in power transformers I-III dimensions.

Thesis for a Candidate Degree in Engineering (Doctor of Philosophy), specialty 05.09.01 "Electric Machines and Appliances" (141 – Electricity, Electrical Engineering and Electromechanics). – Kremenchuk National Technical University named after Mykhailo Ostrogradsky Ministry of Education and Science of Ukraine, Kremenchug, 2019. In the dissertation work the circuit-field calculations methods of parameters in no-load operation of power three-phase transformers I-III dimensions are further developed. New circuit-field models of electromagnetic processes in the active part of power transformer are proposed. The parameters of the external network, design features of active parts and nonlinear properties of active materials are taken into account. Approaches to improve the accuracy and efficiency of numerical implementation are substantiated. The influence of the asymmetric distribution and harmonic composition of phase magnetizing currents on the magnetic field energy in the active part region and the parameters of a three-phase power transformer is determined. Constructive solutions for reducing currents and no-load losses are proposed and substantiated. Key words: power transformer, magnetic system, active part, no-load, magnetic field, numerical simulation, electromagnetic processes, harmonic composition of currents.