Browsing by Author "Levchenko, Serhii"

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    Development of Mathematical Models of Energy Conversion Processes in an Induction Motor Supplied from an Autonomous Induction Generator with Parametric non-Symmetry
    (НВП ПП «Технологічний Центр», Харьків, 2021) Chenchevoi, Volodymyr; Kuznetsov, Valeriy; Kuznetsov, Vitalii V.; Zachepa, Iurii; Chencheva, Olga; Chornyi, Oleksii; Kovzel, Maksim; Kovalenko, Viktor; Babyak, Mykola O.; Levchenko, Serhii
    ENG: The paper presents studies of the system “induction generator-induction motor” with parametric asymmetry on a mathematical model to determine the quality of generated electricity in load operating modes. A mathematical model of the “induction generator-induction motor” system has been developed taking into account losses in steel and parametric asymmetry. The analysis of the transient characteristics of an induction generator when a motor load is connected in symmetrical and asymmetrical modes of operation is carried out. The results of changes in the main characteristics of an induction motor at various degrees of parametric asymmetry in the generator are presented. The quality of the generated electricity was analyzed based on the calculations of the unbalance coefficients for each of the operating modes. The assessment of the thermal state in steady-state conditions was carried out using an equivalent thermal equivalent circuit. Thermal transients were investigated when starting an induction motor from an autonomous energy source based on an induction generator. On a thermal mathematical model, the study of the effect of the output voltage asymmetry on the heating of the connected induction motor was carried out. It is shown that the asymmetry of the output voltage of an induction generator reaches 3–10 % and causes overheating of the windings in excess of the permissible values. A regression model has been developed for studying the operating conditions of an induction motor when powered by an induction generator with an asymmetry of the stator windings. The use of the obtained equations will make it possible to determine the most rational combination of factors affecting the heating of the stator windings of induction machines, in which they will not overheat above the maximum permissible temperature values of the corresponding insulation classes.
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    Modeling of Structural Elements of the Energy-Economic Model «Electric Network - Electric Consumer»
    (ScientificWorld-NetAkhatAV, Karlsruhe, Germany, 2024) Tryputen, Mykola; Kuznetsov, Vitalii V.; Kovalenko, Viktor; Artemchuk, Viktor V.; Levchenko, Serhii
    ENG: Early evaluation of the parameters of electric power quality and maintenance of the corresponding operating modes of electric facilities in work environment is the important scientific and practical task. In terms of real operating conditions, electric mains often demonstrate nonsinusoidal mode characterized by the available harmonics of voltage and current. Deterioration of the electric power quality in the electric supply systems for industrial enterprises results in the decreasing reliability and efficiency of the operation of energy consumers, i.e. asynchronous motors (AM). The known methods to reduce negative influence of low-quality electric power on the AM operation differ with their integration costs and expected economic effect. Nevertheless, the available methods for the selection of protective means for asynchronous motors, operating in the electric mains with nonsinusoidal voltage, have no economic substantiation. Moreover, economic losses of an industrial enterprise due to the operation of asynchronous motors in terms of considerable deviation of the power quality values from the standard ones have not been analyzed to the full extent. The chapter of monograph has shown that currently it is expedient to solve a task of the selection of AM protective means basing on the computational studies, which involve a simulation model representing the interaction of company electric main with the power consumers. There are following structural elements of a simulation model: a generator of linear voltages of the company electric main; a nonlinear electromagnetic and thermal model of an asynchronous motor; and a decision-making block. The chapter of monograph demonstrates the ways to increase reliability of the modeling of electric main parameters.