Main field of study: 010900 Applied Mathematics and Physics
Area of specialization: Electron-Ionic Processes in Liquids and Gases
Course director: Professor Yu.K. Stishkov 
Department of Radiophysics
Scientific adviser: Associate Professor M.A. Pavleino 
Reviewer: Senior Researcher V.P. Afanas’ev

An investigation of transients in power transformers under normal and emergency operation
A.V. Kruzhaev

This work investigates the factors determining the features of current waveforms in windings of a normally operating and faulty transformer in transients that are of interest for its relay protection.
Magnetic equivalent circuits of accepted and original configuration are chosen as a main investigation tool. The influence of transformer design details on model parameters is discussed, and methods of calculation of some of them are proposed.
A special attention is paid to description of the core residual magnetization, which is causing transient current growth and found to be stably high when transformer is disconnected from the network during normal operation. For a faulty transformer, the effect of electric arc properties as well as fault type and location on short-circuit current is discussed in details. Core nonlinearity experienced in emergency modes is noted, whereas usually assumed to be negligible. 
Results calculated using equivalent circuits are in agreement with measured waveforms and those obtained using a transformer finite element model in Comsol Multiphysics package.
The list of publications
1. A.V.Kruzhaev, I.A. Elagin, M.A. Pavleino. Computer simulation of inrush current in single-phase transformer using MATLAB’s Simscape environment//Proc. of ICCTPEA 2014, pp.87-88
2. A.V.Kruzhaev, I.A. Elagin, M.A. Pavleino, V.A. Dmitriev, A.M. Chaly. Computer simulation and experimental study of transient processes in a single-phase voltage transformer//Technical Physics. Vol.60, №2, 2015, pp.188-195
3. A.V.Kruzhaev, I.A. Elagin, M.A. Pavleino. Simulation of internal faults in windings of single-phase power transformer//Proc. of MPEE 2015 (in print)