Підвищення енергоефективності систем власних потреб теплових електричних станцій

Abstract

Dissertation for Candidate of Science Degree in Specialty 05.14.02 "Power plants, networks and systems" (14 – Electrical Engineering) – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2020. The dissertation is devoted to improving energy efficiency and reducing electric power loss in auxiliary systems of thermal power plants by means of applying group frequency regulation of induction motors that drive auxiliary mechanisms. The following tasks were set to achieve the goal: – to study auxiliary power consumption structure in thermal power plants as function of their operation; – to analyze the available parameter regulation methods widely applied to thermal power plant auxiliaries driven by induction motors; – to develop mathematical models of the main auxiliary mechanisms of thermal power plants as load on electric drive taking into consideration various techniques of the mechanisms operation parameter regulation; – to study feasibility of group control application to thermal power plant auxiliaries that are driven by induction motors; – to develop techniques for specifying optimal group frequency of the induction motors supply voltage under group control of the thermal power plant auxiliaries that take into account operation conditions of the group auxiliary consumer; – to work out practical recommendations for implementation of the dissertation research results in Kharkiv Combined Heat-and-Power Plant 3 aiming at improving energy efficiency of the plant auxiliary system. The object of research is physical processes occurring in electrical and electromechanical equipment of thermal power plant auxiliary systems. The subject of research is parameters and characteristics of the main auxiliary power consumers of thermal power plants. Research methods. The dissertation research is based on the system approach to conducting theoretical and experimental investigations that employs mathematical modeling, numerical techniques for solving nonlinear equations, the least square method for approximation of tabulated ratings of centrifugal mechanisms, linear interpolation of discrete data sets for specifying characteristics of thermal power plant permanent equipment, discrete multivariable search for determining maximum efficiency values when solving an optimal control parameter problem for centrifugal mechanisms driven by induction motors, statistics methods for analysis of auxiliary power consumption structure in thermal power plants. The following scientific results are obtained in the dissertation research: – Mathematical models of thermal power plant auxiliary mechanisms have been advanced, as compared with the available models, to allow conducting detailed analysis and obtaining the general characteristic of auxiliary power consumption in thermal power plants under various operation conditions. – The basic principles of energy-saving measures realization in thermal power plants through grouping auxiliary electricity consumers with close operating modes have been substantiated, which allows reducing investments in energy efficiency under the plant auxiliary systems renovation and modernization. – A technique for determining power consumption of thermal power plant auxiliary group consumer that takes into account the applied parameter regulation method has been introduced, which allows specifying the general energy saving potential for the plant auxiliaries. – A technique for determining the optimal group frequency of induction motor supply voltage for different groups of thermal plant auxiliaries that takes into consideration operation conditions and weighted average efficiency of the auxiliary group consumer has been developed, which allows noticeably reducing auxiliary power consumption in thermal power plants. The dissertation has been performed according to the research plans of the Department of Electric Power Stations in the National Technical University "Kharkiv Polytechnic Institute" (NTU "KhPI") and under Ministry of Education and Science of Ukraine Research Project DR № 0115U000528 "Development of theory and scientific-and-methodological basics for creation and modernization of turbogenerators that meet state-of-the-art requirements of the Power System of Ukraine". The project was performed jointly with the NTU "KhPI" Department of Electric Machines.