Problemele Energeticii Regionale最新文献

{"title":"Balancing Properties of the Booster Transformer with the Longitudinal-Transverse Regulation","authors":"Dumitru Zaitsev, I. Golub, M. Tirsu, Danila Caloshin","doi":"10.52254/1857-0070.2023.1-57.06","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.06","url":null,"abstract":"The current development of the power industry involves various kinds of FACTS, being element of the Smart Grid and controlled by power electronics used for increasing the flexibility of electrical networks. Thus, the development and research of such devices are relevant. The study object is a controller belonging to the \"Sen\" family of transformers, which provides regulation of voltage and power flows in networks. The aim of the work is to study the balancing properties of booster transformer, which has an extended range and higher control accuracy in various modes. The goal was achieved during research carried out on the basis of structural simulation models. The most significant result was statement that the device under study has a pronounced per-phase balancing effect, which is preserved in various modes, including reverse ones. The main result can be consider that the proposed device, in comparison with the currently existing transformers of the \"Sen\" family, due to the extended range and accuracy of voltage regulation, allows using it when working, both for symmetrical and asymmetric loads. It is shown that the proposed technical solution provides ample opportunities for longitudinal-transverse phase-by-phase voltage regulation. Moreover, the deviations of parameters characterizing the quality of electricity, such as modules and voltage angles, do not go beyond the limits regulated by the requirements of the standard. The results obtained allowed us to conclude that this device can be used to solve the problem of coordinating the operation of two asymmetric systems in different operating modes.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42739153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat Transfer Slot Matrix for Compact Rotary Heat Exchangers with Ultra-High Regeneration Ratio for Microturbines","authors":"A. Kostyukov, L. Kosach","doi":"10.52254/1857-0070.2023.1-57.10","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.10","url":null,"abstract":"This paper considers the problem of the influence of distancing elements in slot matrix channels on the thermohydraulic characteristics of the matrix of a rotary heat exchanger having various values of the height of the slot channels. The following tasks were carried out: mathematical modeling of thermohydraulic processes in different slot channels having constant height along them (from 0.3 mm to 0.5 mm); analysis of the influence of the slit channels' height, the number of distancing elements in rows, the distance between rows and the total number of elements on the average value of the Nusselt number and on the pressure drop; analysis of the effect of changes in speed and temperature conditions on thermal and hydraulic characteristics. The most important results are the following facts: the influence of the relative location of the distancing elements on the thermohydraulic characteristics of the flow is negligible; changes in the temperature and speed regime of the laminar flow practically does not affect the intensity of convection in the matrix channels; an increase in the height of the slot channel leads to a relatively small decrease in the average value of the Nusselt number. The significance of the results obtained is that they can be the basis for adjusting the methods of design calculations of rotary heat exchangers taking into account the decrease in thermal efficiency caused by the presence of distancing elements in the channels of their matrices. Recommendations can be made to minimize the number of distancing elements without considering their mutual location.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41334979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Use of Coplanar Transmission Lines for Protecting Receiving Antenna Systems from Powerful Electromagnetic Radiation in a Wide Frequency Range","authors":"O. Sotnikov, Konstantin Petrov, Sergey Udovenko, Y. Gnusov, Valerii Radchenko, S.V. Kaliakin, Kateryna Gromliuk, O. Kyrychenko","doi":"10.52254/1857-0070.2023.1-57.11","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.11","url":null,"abstract":"The goal of the work is to expand the frequency range of operation of coplanar waveguide transmission lines as broadband high-speed superconducting protection devices against powerful ultrashort electromagnetic radiation, and to apply them in antenna devices of radio electronic systems designed to ensure the reliable operation of critical infrastructure facilities. The aim is achieved by solving the following tasks: investigating the electrophysical properties of coplanar transmission lines, in particular, capacitance, surface and wave resistance in different phase states that arise under the influence of powerful electromagnetic radiation, and determining the main factors for effective protection in a wide frequency range, designing protective devices. The most important result is the establishment of the possibility of using coplanar transmission lines as protection devices in a wide frequency range up to 100 GHz, as well as the establishment of the dependence of their main characteristics on the design parameters of the superconducting protection device. The significance of the obtained results consists of solving a complex problem of providing protection of antenna systems against powerful ultrashort radiation by establishing an analytical relationship between the electrophysical parameters of coplanar waveguide transmission lines, which are in different phase states determined by the influence of powerful electromagnetic radiation, and their design parameters. The peculiarity of the obtained results is in the clarification of the dependence of the wave resistance of the coplanar waveguide transmission lines in superconducting, mixed, and normal phase states on the change of their active component of surface resistance, determined in turn by the design characteristics of the protective device. The difference from the known works lies in obtaining relationships for determining the wave resistance of protective devices in different phase states.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49143867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the Energy Efficiency of the Air Conditioning System Based on Absorption Refrigeration Machine with Connection of Heat Pump and Solar Collectors","authors":"Evgheni Mereuta, A. Suhih","doi":"10.52254/1857-0070.2023.1-57.08","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.08","url":null,"abstract":"This article proposes and analyzes a circuit solution for providing heat supply to the generator of an absorption refrigeration machine (AHM) in centralized air conditioning systems using a heat pump unit (HPU) and solar collectors (SOL). Previously, such schemes have already been considered in the scientific works of Russian and foreign authors. The aim of the work is to propose new circuit solutions aimed at improving such systems, as well as confirming higher energy efficiency. This goal is achieved by solving the following problems: additional supply of the circuit with a common storage tank, operation of the absorption refrigeration machine generator and the condenser of the heat pump unit based on a common heat exchanger. Such a solution for the air conditioning complex based on an absorption refrigeration unit has been proposed for the first time. The most important results are the possibility of obtaining high values of the coefficient of performance, the possibility of achieving a number of technological advantages, increasing reliability and efficiency, as well as reducing the metal consumption of an absorption-type plant operating from solar collectors and a heat pump plant compared to similar systems. The significance of the obtained results lies in the fact that the use of a common storage tank and a combined heat exchanger (AHM generator / HPU heater) provides a significant increase in the coefficient of performance, a decrease in the metal consumption (reduction in costs) of the main equipment.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47521742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of the Experimental Stand for Studying and Testing Digital Protection Terminals","authors":"Mykhailo Shabovta, O. Besarab, V. Plis","doi":"10.52254/1857-0070.2023.1-57.02","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.02","url":null,"abstract":"However, the approach to designing laboratory stands for training students and electrical personnel on the specifics of using digital protections in most cases has remained the same, which does not allow for fully realizing their potential. The purpose of the work is to improve the quality of the knowledge and practical skills received by students in the work with digital protection blocks. To achieve the goal, a specialized laboratory stand for testing digital security terminals has been developed. The stand consists of a mathematical model of the protected object, implemented in the form of a computer program and hardware, which allows real-time conversion of changes in model mode parameters into physical signals transmitted to the digital protection device. The stand provides the terminal feedback with the model, which makes it possible to study the protection behavior in the characteristic operating modes of the protected element. The protection of the \"line-transformer\" block using the Siprotec 4 7SJ6 Siemens terminal is considered. It is possible to calculate the protection operation parameters, configure the digital protection device, and also check the correct operation of the protections by automatically simulating normal and emergency operation modes of the protected object. The software and hardware of the stand makes it easy to expand its capabilities by adding new models of power system objects and other digital protection devices. The equipment used in the developed stand does not require significant capital investments, which makes this approach accessible to higher educational institutions.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49314155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the Numerical Modeling Results of the Associated Petroleum Gas Combustion in the Convertible Chamber in a Micro Gas TPP","authors":"O. Matyunin, Alena Bachev, N. Shilova","doi":"10.52254/1857-0070.2023.1-57.09","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.09","url":null,"abstract":"When developing prospective gas turbine plants or converting existing ones for burning nonstandard fuel gases, one of the main tasks is creation of low-emission combustion chambers with stable combustion. At the stage of sketch design, the parameters of recycling chambers are usually determined using engineering calculation methods. Methods of numerical modeling of the working process allow to clarify the obtained parameters and significantly reduce the costs of creating a combustion chamber thanks to the numerical experiment. The purpose of this work is to develop recommendations for converting existing combustion chambers of microgas-turbine power plants to utilize nonstandard fuel gases. To achieve the goal, the problem of numerical modeling of the working process with and without a stepwise air supply to the combustion zone was solved. The most significant result of the conducted studies is provision of stable combustion due to the change in the medium speed along the combustion zone with stepwise air supply and due to intensification of the reverse currents zone from the swirler with continuous air supply. The significance of the obtained results is that the proposed recommendations for converting a low-emission combustion chamber from components (kerosene+air) to components (combined petroleum gas+air) while keeping the diameter and length of the chamber unchanged, with changing the location of only the side holes. In this work, a three-dimensional numerical model of turbulent combustion for utilizing associated petroleum gases was developed to take into account the real operational conditions in a two-zone combustion chamber and analyze the performance characteristics.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44122436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Steady State Two-Phase Short Circuit Modes Of Phase-Shifting Autotransformer with Hexagon Scheme and with Adjusting Autotransformer","authors":"V. Bosneaga, V. Suslov","doi":"10.52254/1857-0070.2023.1-57.05","DOIUrl":"https://doi.org/10.52254/1857-0070.2023.1-57.05","url":null,"abstract":"The purpose of work is to investigate two - phase short-circuiting modes of new autotransformer FACT’s - type device and is intended for power systems flexible connection. The developed mathematical model contains the main phase-shifting and additional regulating autotransformers. The model allows studying of asymmetrical modes of such schemes, including the un-identical load connection in different phases of phase-shifting transformers. Visual vector diagrams of winding’s voltages, currents and relative magnetic fluxes of magnetic core legs for main and regulating autotransformers for the modes with two-phase short-circuiting with and without ground have been elaborated. It is shown that significant distortions of the polygon shape occurred. It is revealed that in two-phase short - circuiting mode without ground, and the loads identically connected in different phases, the relative magnetic fluxes of the legs of main and regulating autotransformers are asymmetrical, but their sum is zero, and the magnetic flux does not come out into surrounding space. Load currents in this mode contain only direct and reverse sequences components. When the load is un-identically connected in different phases, significant zero-sequence currents occur, and magnetic flux goes out into surrounding space. However, load currents do not contain symmetrical components of zero sequence. A similar analysis of two-phase short circuit modes with ground showed that even with the identical connection of the loads, there is zero sequence both in the magnetic fluxes and in the load currents. Moreover, zero sequence is present when the load is connected differently on the phases.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48149244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Problem of Choosing a Steganographic Container in Conditions of Attacks against an Embedded Message","authors":"I. Bobok, A. Kobozieva, S. Sokalsky","doi":"10.52254/1857-0070.2022.4-56.07","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.4-56.07","url":null,"abstract":"Steganography is the perspective area of information security. The reliability of the stegano- graphic system, its stability is affected by the carrier – a container, which is considered in the paper as a digital image. The aim of the work is to increase the resistance of a steganographic system to attacks against an embedded message by developing a method for choosing a contain-er from a finite set of available digital images that ensures the transmitted message the minimum (close to the minimum) possible sensitivity of the generated steganographic message to disturb-ing influences under consideration with the selected steganographic algorithm. The goal was achieved using a theoretical study of perturbations of the formal parameters of the container ma-trix, as a result of steganographic transformation and active attacks, which made it possible to introduce a new formal representation for information protected from perturbing influence E, as the difference of low-rank approximations of container matrices and steganographic messages. The most important result of the work is the development of a container selection method ready for practical implementation. The efficiency of the developed method exceeds the efficiency of analogs, it remains high, regardless of the used steganographic method, which allows increasing the overall resistance of the steganographic system to attacks against the embedded message. The significance of the obtained result lies in the use of the developed method of increasing the stability of the steganographic system to attacks against the embedded message.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42071402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perspective Ways of Energy-Efficient Modernization of Heat Supply Systems Based on Heat Pump Technologies","authors":"V. Petrash, V. P. Baryshev, L. Shevchenko, E. Geraskina, N. Danichenko","doi":"10.52254/1857-0070.2022.4-56.05","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.4-56.05","url":null,"abstract":"This work is devoted to determination a generalized indicator for a preliminary assessment of the conditions for increasing the efficiency of modernized systems of centralized and decentralized heat supply using heat pump technologies. This goal is achieved through a critical analysis of the results of the actual state of pipelines and equipment, known approaches to the reconstruction of heat supply systems and the establishment of a generalized indicator of the conditions for increasing the efficiency of using primary fuel energy. This made it possible to formulate a generalized approach to the modernization of heat supply systems with the introduction of heat pump technologies. The most important result of the study is the established generalized dependence of the assessment of the increase in the efficiency of heat supply systems on the initial conditions of regime parameters with the rationale for the feasibility of modernizing district heating systems based on the diverse phased introduction of heat pump technologies at all stages: generation, transportation, distribution, conversion and controlled consumption of heat by subscriber system. The significance of the obtained research results lies in the fact that the proposed approach to the modernization of centralized and decentralized heat supply systems based on heat pump installations with real conversion factors in the range (3--5) with an increase in the available heat potential is to increase the efficiency and expand the use of heat from primary fuel with its savings of 1-2.7 times.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47640574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the Idle time of Single-Chain and Double-Chain Overhead Power Lines of 6–10 kV by Methods of Queuing Theory","authors":"V. Basmanov, V. Kholmanskikh","doi":"10.52254/1857-0070.2022.4-56.01","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.4-56.01","url":null,"abstract":"The aim of this work is to substantiate the idle time evaluation of the overhead power line (OPL) according to the reliability indicators of its main elements using the probability value of the overhead power line availability factor. Statistical studies of the 17 OPL were performed to achieve this goal. The results of the statistical data processing made it possible to consider over-head lines as objects of a multiple action, and their failure and recovery flows as the primitive Poissonian flows. The calculation of the Wilcoxon and Pearson criteria confirmed the uniformi-ty of the statistical material both in terms of failure times and recovery time for all 17 studied OPL, which allowed combining the uniform statistical data into two representative samples, ac-cording to failures and recoveries, for the generalized district OPL and calculate its reliability indicators. The most significant result is the justification of applying queuing theory methods to evaluate the idle time of 6–10 kV single-chain and double-chain of overhead lines. The signifi-cance of the results obtained consists in that a simple engineering method is proposed to evalu-ate the availability factor of the overhead power line according to the reliability indicators of its main elements, which allows predicting the idle time of the overhead line for the upcoming cal-endar year of its operation. The newly obtained availability factors of the main overhead line elements can be used in the overhead power lines’ design.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47947985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}