Кафедра "Електротехніка та електромеханіка" <br>(в 2013 році злиття кафедри "Теоретичні основи електротехніки" та кафедри "Автоматизований електропривод")

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http://crust.ust.edu.ua/handle/123456789/1925

ENG: Department "Electrical Engineering and Electromechanics" in 2013 the Merger of the Departments
"Theory of Electrical Engineering" and "Automatic Electric"

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Electrodynamics of Power Losses in the Devices of Inter-Substation Zones of AC Electric Traction Systems
(MDPI, Basel, Switzerland, 2022) Nikitenko, Anatolii V.; Kostin, Mykola O.; Mishchenko, Tatyana M.; Hoholyuk, Oksana
ENG: This article presents a new method for the estimation of active power losses based on a “field” approach, i.e., on the theory of the electromagnetic field and the theory of propagation of electromagnetic waves in a dielectric medium. Electromagnetic waves are assumed to transmit energy from the traction substation to electric rolling stock through the airspace of the inter-substation zone (i.e., not through the wires of the traction network) and meet electrically conductive surfaces on their way. The waves are partially reflected from the surfaces and partially penetrate them, thus creating thermal losses, the determination of which is the main task of this article. The analytical expressions for specific losses of active power are obtained by solving the system of Maxwell’s equations. Calculations of specific power losses in the catenary, rails, roofs, and bottoms of carriages and electric locomotives are performed. Power losses in carriages and electric locomotives are found to be at least 7%. A comparative assessment of the magnitude of total power losses of different types obtained by the “field” and “circuit” approaches is provided, which has established that “conditional” losses correspond to losses in rails, train carriages, and electric locomotives.
Fryze Reactive Power in Electric Transport Systems with Stochastic Voltages and Currents
(2020) Kostin, Mykola O.; Mishchenko, Tetiana; Hoholyuk, Oksana
ENG: The paper presents the theoretical foundations of reactive power and additional power losses in a direct current electric transport system. Numerical calculations of inactive power and losses in the circuits of electric DC locomotives and trams have been carried out. Discrepancy between the sign of the instantaneous power and the presence of exchange processes in non-linear circuits of electric transport systems with stochastic voltages and currents is discussed.
Inactive Power in Electric-Traction DC Transport Systems
(Revijo izdaja Elektrotehniška zveza Slovenije, 2022) Kostin, Mykola O.; Mishchenko, Tetiana; Hoholyuk, Oksana
ENG: The paper presents a theoretical background to determine the inactive power consumption features, i.e. the reactive power according to S. Fryze approach of the electric transport systems. Traction electric circuits of transport facilities of electric locomotives, feeder traction substations and city trams used in Ukraine demonstrate three features of the reactive power. According to the classical method, the inequality between the active and total power indicates the presence of the reactive power. The second feature is the time variation of an instantaneous impedance or instantaneous conductivity. The third is the inequality between the instantaneous reactive power to zero and the nature of its sign throughout the time of the electric power system consumption. The reactive power consumption gives rise to considerable additional power losses in the electric traction transport systems.
The Principle of Creating a «Smart» Electricity Meter in Electric Traction Networks with Stochastic Electromagnetic Processes
(Lviv Polytechnic National University, Lviv, Ukraine, 2021) Kostin, Mykola O.; Mischenko, Tetyana; Hoholyuk, Oksana
ENG: Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.
Transient Stochastic Processes in Power Circuits of Electric Transport Systems
(IEEE, 2019) Kostin, Mykola O.; Mishchenko, Tetiana; Liashuk, Vitalii; Hoholyuk, Oksana; Stakhiv, Petro
ENG: The analytical method for the purpose of analyzing the transient processes occurring in the power traction circuits of DC electric transport systems allowing to take into account existing stochastic character of electric traction voltages and currents has been proposed. The method is based on using a modified form of Duhamel's integral adapted to the theory of random processes, in which the weight function is determined by the solution of the Wiener-Hopf correlation integral equation. Based on relationships of the proposed method the numerical calculations of transient stochastic characteristics (the function of mathematical expectation, the function of correlation, root-mean square deviation and dispersion) of the locomotive current in freight train operation of the Prydniprovsk railway were carried out.

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