Browsing by Author "Bondar, Oleh I."
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Item Experimental Investigation of Actual Stuation of using and Accounting of Recovered Energy of Regenerative Braking Mode at the DC Traction System(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Bondar, Oleh I.; Ustymenko, Dmytro V.; Kurylenko, Olena Ya.; Kedria, Mykhailo M.; Karzova, Oksana O.; Krasnov, Roman V.; Baliichuk, Oleksii Yu.ENG: Abstract. This paper deals with the problems of enhancement of registration and distribution of electric energy which can be obtained from DC electric locomotives by the regenerative braking. According to theoretical researches, it is possible to return approximately 8 - 12% of electric energy which is consumed for electric traction by using of a regenerative braking mode. However in recent years for electric traction networks of JSC “Ukrainian Railways”, this index doesn't exceed 2.6%. So we consider that the regenerative braking is one of the most prospective ways for energy saving in electric railway transport. Results of the experimental researches which were executed on DC traction substations and VL11M6 electric locomotives are described in this paper. Instantaneous values of voltage and current in different modes have been obtained. The electric energy balance for experimental zone has been performed. Also the ways of distribution and consumption of energy of regenerative braking mode have been analyzed. On this basis of the executed investigations, recommendations about providing of supercapacitor energy storage system for Ukrainian railways are proposed.Item Fryze Reactive Power of Trams in Eeffective Stochastic Rrecuperation Processes(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Bondar, Oleh I.; Kostin, Mykola O.; Mukha, Andrei; Sheikina, Olha H.; Levytska, Svitlana І.ENG: Abstract. Urban electric transport system, particularly tram systems, is not a direct current system not only in traction mode but in regenerative modes as both voltage on a collector and regenerative current are stochastic abruptly variable processes. The above- mentioned facts determine availability of Fryze’s reactive power in this system that flows from a railway substation to trams, leads to incidental losses of energy and significantly reduces its quality. So evaluation of power effectiveness of the system in electrical trams operation is impossible without determining the level of reactive power in this system. We have analytical expression of reactive power by Fryze. Numerical calculations for trams type T3D and T4D in regenerative braking modes are done. Probabilistic statistical data processing operation of reactive power expressions is done. It is determined that reactive power changes in the limit of 10…100 kilo-volt ampere reactive with mathematical expectation – 37,0 kilo-volt ampere reactive. Statistical allocation of random power values are different. Numerical calculations of incidental losses, energy of recuperation are done and they range supplementary – 20% from total losses. It is stated that coefficient of reactive power of system route of trams is exceeding permissible value 0,25.Item The Impact of Connecting a Wind Power Plant on Emergency Modes of a Traction Substation of an AC Traction System(Springer, Cham, 2022) Kachan, Yurii; Kuznetsov, Vitaliy V.; Bondar, Oleh I.ENG: Among the countries of South-Eastern Europe, Ukraine has the greatest technical potential for the implementation of renewable energy sources, and the main part of it is wind power engineering. The traction power supply system of the railways in Ukraine can become an important transiter and consumer of electricity generated by wind power plants. At the same time, the task of ensuring traffic safety and uninterrupted power supply of traction loads requires a preliminary study of the influence of the connected wind power plant capacity on the growing short-circuit currents in the distributive units of the traction substation to which the specified connection is planned. This paper proposes a way to implement such prediction based on a systematic approach, in which a traction substation and an integrated wind power plant are considered as a single electrical-engineering complex, the sources of which work to power the short-circuit point. In previously published studies, the authors usually consider the processes in renewable energy sources and in the traction power supply system separately, without taking into account the mutual influence. The analysis of processes in the short-circuit mode is proposed to perform according to the equivalent circuits for the specified electrical-engineering complex developed by the authors with various possible options for connecting a wind power plant using mathematical modeling with proven methods of theoretical electrical engineering. The peculiarity of the study presented in this paper is also the use of the multiplication factor of the short-circuit current as a criterion for assessing the impact of the power of the connected wind power plant on the short-circuit currents of the traction substation. In our opinion, the coefficient applied by us more clearly characterizes the specified influence in comparison with operating values or complex sizes of short-circuit currents.Item Improvement of Energy Indicators of Conventional Electric Driving Asynchronous Motors of Non-Standard Technological Equipment at the Enterprises for Repair of Railway Rolling Stock Through the use of Energy-Saving Motors(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Bondar, Oleh I.; Baliichuk, Oleksii Yu.; Karzova, Oksana O.; Krasnov, Roman V.; Marenych, Oksana L.; Ustimenko, DmytroENG: Abstract. The purpose of this work is to study the utilization efficiency of electric driving energy-saving motors of non-standard technological equipment meant for repair of railway rolling stock, in terms of improvement of energy performance, i.e. improvement of efficiency factors and power factors, and decrease of power losses as compared with the most commonly used “conventional” asynchronous motors. There are two options for improvement of the energy performance of electric drives of non-standard technological equipment: replacement of a conventional motor with an energy-saving one similar in terms of nominal voltage, rotational speed, power, etc.; changeover of stator winding from “delta” to “star”. A special technique has been proposed to determine the effectiveness of this changeover in terms of improvement of energy indicators. Comparison of the real values of the energy indicators of conventional motors and energy-saving motors in the case under consideration is required to perform the technical and economic calculations when solving the problem of the expediency of replacement of conventional asynchronous motors with energy-saving motors in the abovementioned equipment.Item Reactive Power Compensation for Non-Traction Railway Consumers(Institut Kolejnictwa, 2020) Mukha, Andrii M.; Bondar, Oleh I.ENG: This paper deals with the problems of power supply efficiency for non-traction railway customers. Unlike public distribution networks, the non-traction power supply network is within the zone of influence of electromagnetic fields and the conductive influence of the distorted traction current. As a result, poor power quality and additional losses are typical for non-traction railway networks. Subsequently, conflicts due to the low quality of electricity may arise between the railway and its customers powered by the distribution networks of the railway. The influence of a reactive power compensation device on the voltage drop in a non-traction power line is investigated in the article. The implementation of reactive power compensation allows voltage losses during its transmission to the final consumer to be reduced by almost 5% and electricity losses by 3%.Item Reactive Power Compensation for Non-Traction Railway Consumers (preprint)(Institut Kolejnictwa, 2020) Mukha, Andrii M.; Bondar, Oleh I.ENG: This paper deals with the problems of power supply efficiency for non-traction railway customers. Unlike public distribution networks, the non-traction power supply network is within the zone of influence of electromagnetic fields and the conductive influence of the distorted traction current. As a result, poor power quality and additional losses are typical for non-traction railway networks. Subsequently, conflicts due to the low quality of electricity may arise between the railway and its customers powered by the distribution networks of the railway. The influence of a reactive power compensation device on the voltage drop in a non-traction power line is investigated in the article. The implementation of reactive power compensation allows voltage losses during its transmission to the final consumer to be reduced by almost 5% and electricity losses by 3%.Item Study of Short Circuit Currents in a Distributed Traction Power Supply System with Renewable Electric Power Sources(IEEE, 2022) Kuznetsov, Valeriy; Kuznetsov, Vitaliy V.; Bondar, Oleh I.; Rojek, Artur; Hubskyi, Petro; Stypulkowski, PiotrENG: The problems of changing short-circuit currents in a distributed traction system for using renewable energy sources were analyzed in the article. Literary sources analysis shows a further tendency for increasing the share of renewable energy sources in the total energy balance of the country and a particular increase in electricity consumption by electric traction. Goal. The main goal of the study is a method development with its practical application to impact estimation of power-boost points that connected to the traction network with energy using from renewable sources on short-circuit currents values. Methodology. The method that has developed in this study is based on well-known approaches for equivalent circuits of electrical equipment definition, but elemenst pair like «solar panel - inverter» it reproduces as EMF with equivalent resistance, which significantly simplifies further calculations. Results. The study results show that the application of power-boost points will not lead to a significant increase of short-circuit currents in the traction network even if the power of photovoltaic sources will be comparable with the power of existing converting units on traction substations. This is because of the physical nature of the photovoltaic panel and its power mode which usually closer to the current source with high internal resistance. Practical value. This also allows us to conclude that in most cases from the point of view of changing the short circuit currents the integration of power-boost points that are powered by solar power plants is quite possible with operating sections of the traction power supply system.