Shpak O. Modelling of periodic electromagnetic processes in power transformer of power systems

Object of research - periodic electromagnetic processes in power transformers as elements of the electric power system. Subject of research - models and methods of analysis of periodic processes in power transformers of the electric power system. Research methods - The theoretical and methodological basis of the dissertation work were the positions of theoretical electrical engineering, the theory of electromagnetic energy converters, on the basis of which mathematical models of single- and three-phase power transformers were obtained, the theory of nonlinear differential equations, numerical integration methods, which allowed to improve Newton's method for solving the systems of differential equations equations and extend the possibility of evaluating parametric sensitivity within the theory of sensitivity. Scientific novelty of the obtained results consists in the creation of mathematical models of power transformers as elements of electric power systems for the study of periodic electromagnetic processes in them and improvement of their technical and economic characteristics. In particular: the mathematical models of single- and three-phase transformers based on the system of differential equations presented in the normal form of the Cauchy have been improved and allow one and the same methodological basis to analyze both transient and periodic periodic electromagnetic processes in power transformers; For the first time, a method for assessing the impact of power transformer equipment on the energy efficiency of power supply systems has been developed, based on the application of developed mathematical models for the creation of power transformers with spatial magnet, the use of which creates conditions for reducing power losses during its transportation and improving the quality of voltage in electric networks; the method of estimating the sensitivity to the initial conditions is developed due to the presentation of the matrix of sensitivity by the product of two other matrices, the first of which is the matrix of the coefficients of the initial system of equations of state that reproduces the transient reaction of the system on the period, and the second is a matrix whose elements are calculated from the variational equations and are exponential free component, which suppresses the forced transient reaction. This allows us to investigate transient, periodic (stationary) processes and static stability of electric networks, the elements of which are transformers, based on a single algorithm. The practical value of the results. The proposed models and methods are brought to the level of applied regulations and recommendations and can be used in organizations conducting research and analysis of electromagnetic processes, forming a strategy for the development of electric power systems, optimizing investment plans for the development of elemental basis of power systems. As a result of the development of this work as separate modules and standard subroutines, the functional capabilities of design organizations are expanding. The main results of the research were introduced into the practical activities of PJSC "Khmelnytskoblenergo", based on which a three-phase transformer with a power of 100 kVA with a voltage of 10 / 0.4 kV with a monolithic magnetic system and a group of 25 kVA voltage transformers of 10 / 0.4 kV with spatial magnetic system. Methods and means of analysis of electromagnetic processes are used in the development of energy-efficient heating and air conditioning systems of industrial premises using new types of transformers, universal heat accumulator and combined systems for compensation of peak load of electric networks based on super-capacitors. Branch of application – electrical energy industry.