Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations最新文献

{"title":"Assessment of Thermodynamic Efficiency of the Belarusian Energy System. Part 2","authors":"V. N. Romaniuk, A. A. Bobich, T. V. Ryzhova, T. V. Bubyr, V. V. Yanchuk, Y. S. Yatsukhna","doi":"10.21122/1029-7448-2023-66-2-141-157","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-2-141-157","url":null,"abstract":"The energy system is a structure that is among the most complex artificial objects, the successful functioning and development of which is absolutely necessary to ensure the livelihoods of a modern state. In this regard, its continuous monitoring with obtaining reliable and objective performance indicators is undoubtedly in demand. Traditional key energy indicators (specific consumption of conventional fuel for electricity generation and heat release) do not give a complete picture of the operation of the power system for such complex structures and in some cases are calculated incorrectly. The present paper proposes to add a well-known, but practically unused exergetic efficiency coefficient to the range of traditional characteristics. Its application expands the monitoring capabilities and increases the objectivity of the evaluation. For the first time, the analysis of various periods (annual, heating and inter-heating) was carried out on the example of thermal power plants (CHP) of the Unified Energy System of Belarus. The relative power generation of the CHP before the commissioning of the Belarusian NPP was estimated at ≈45 %, and after commissioning it decreased to ≈39 %. More than half of the annual consumption of thermal energy in Belarus is accounted for by heat-generating sources, while thermal power plants provide up to 88 % of heat output. The installed electric capacity utilization factor, the extraction factor and the average annual specific generation of electricity on thermal consumption for each CHP separately have been determined. The results are presented graphically, which makes the content more informative and facilitates the perception. Solutions have been proposed to improve the efficiency of the CHP.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136269056","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":"Research of Regenerative Braking Strategy for Electric Vehicles","authors":"Van Nghia Le, Hoang Phuc Dam, Trong Hoan Nguyen, S. V. Kharitonchik, V. Kusyak","doi":"10.21122/1029-7448-2023-66-2-105-123","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-2-105-123","url":null,"abstract":"In the context of global energy instability caused by the transformation of global demand for energy and energy resources, one of the most important areas in the automotive industry is the development of electric vehicles. Serial production of high-tech electric vehicles with a long range contributes to the stabilization of the energy market and the sustainable development of the whole fuel-energy sector. To evaluate the possibility of optimizing the electric vehicles energy consumption, various regenerative braking strategies are discussed in the article based on the Nissan Leaf electric vehicle, which simulation model includes submodules of the traction electric motor, hybrid braking system, traction rechargeable battery and tires. In order to test the adequacy of the simulation model to reproduce the relationship between the operating parameters of electric vehicles various systems and evaluate their ability to regenerate energy during braking the simulation results were compared with the actual experimental data published by the Lab Avt research laboratory (USA). The relative error of the mathematical modeling results of the braking energy regeneration processes is 4.5 %, which indicates the adequacy of the electric vehicle simulation model and the possibility of its using as a base for research and comparison of the energy efficiency of various regenerative braking strategies. As the results of experiments have shown, the usage of the proposed control strategy of the regenerative braking maximum force allows increasing 2.14 times the energy recharging traffic to the battery as compared with the basic control strategy of fixed coefficient braking forces distribution with an increase in braking distance by 10 m. An alternative control strategy of regenerative braking optimal efficiency as compared to the basic control strategy provides a reduction in braking distance by 13.2 % at increasing by 84.4 % the amount of energy generated by the electric motor for recharging the batteries. The carried out investigations confirm the available significant potential for improving the efficiency of the electric vehicles usage by developing the control strategy and algorithms of the braking energy regeneration.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85050544","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":"Operational Identification of Resistances of Wires of 380 V Distribution Networks by Automated Accounting Systems","authors":"","doi":"10.21122/1029-7448-2023-66-2-124-140","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-2-124-140","url":null,"abstract":"Four-wire distribution electrical networks of 0.4 kV equipped with automated systems of electrical energy accounting are considered. The problem of identifying the resistances of the wires of the distribution network is solved on the basis of the effective values of voltages and currents, as well as of their phase shift angles obtained by the accounting system in the power supply node of the network and from its subscribers for the selected observation intervals. A brief analysis of the known methods and technologies used in this area of research is carried out. The importance of the formulated problem for applied problems, such as control and diagnostics of electrical energy losses, as well as the technical condition of the network, is noted. A method (algorithm) is proposed that allows determining unknown, unequal complex resistances of inter-subscriber sections of the distribution network. In these resistances, the reactive components are considered equal within the inter-subscriber section; the active components differ due to the influence of unequal flowing currents and/or weather factors. At the same time, data from two different network operating modes are required, which are selected based on the analysis of the dynamics of changes of supply currents and/or voltages by the accounting system device connected to the power supply node. Considering that the active resistances of the wires must remain unchanged, the mode that is used for calculations is the one that is before the change in power consumption in the network and the next one immediately (about 0.1 s) after it. An example of a calculation that demonstrates the reliability of the proposed equations of the method that has been developed on a simulated distribution network is given. The research results are focused on the improvement of automated accounting systems and the implementation of their new functions that elevate the reliability of distribution networks, as well as allowing for the rapid identification of non-technical losses of electrical energy.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84553639","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":"Composite Granular Fuel","authors":"L. Ovchinnikov, N. Shpeynova, N. L. Ovchinnikov, A. Mitrofanov, S. Vasilevich","doi":"10.21122/1029-7448-2023-66-1-91-100","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-91-100","url":null,"abstract":"Currently, the topical trend in the development of energy complexes in a number of countries is the expansion of the solid fuel use, which is largely provided by the use of various types of local renewable fuels. The latter often have high thermal properties (heat of combustion, ash content, etc.), but have low or poorly predicted physical and mechanical characteristics (strength, granulometric composition, etc.). These circumstances practically make stable and efficient operation of automation systems, mechanization of transportation of pellets, and technological processes of boilers impossible. The formation of a composite fuel with specified physical and mechanical properties provides a solution to this problem. The structure of the composite fuel based on peat, sawdust, cellulose and modifier was established at the previous stages of our work. However, in case of a given composition, the physical and mechanical characteristics depend on the operating and technological conditions for obtaining granules. In this paper, a statistical and experimental study was carried out aimed at finding rational technological conditions for granulating and drying composite fuel particles with a given mass ratio of components. To prepare fuel pellets of a given size from the initial fine-fraction components, a laboratory installation was used, the main elements of which were a Z-shaped mixer, a screw granulator, and a fixed bed dryer. The influence of independent variables on the strength and final moisture content of finished pellets of composite fuel was determined within the framework of a full factor experiment. The paper presents graphical images of response surfaces characterizing the specified influence of variable factors. The obtained regression dependences describing the influence of factors on the target properties of granules are linear in nature. The latter limits the possibility of using gradient optimization methods and creates the need to search for rational conditions, taking into account the limitations caused by the technical and economic parameters of obtaining finished fuel pellets.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72903115","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 the Kinetics of Heat and Moisture Exchange during Heat Treatment and Drying of Thin Wet Thermal Insulation Materials","authors":"A. I. Ol′shanskii, A. Golubev","doi":"10.21122/1029-7448-2023-66-1-66-79","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-66-79","url":null,"abstract":". The kinetics of drying of thin heat-insulating flat materials has been studied. The approximation of the drying rate curve by various methods is presented. When determining the duration of drying by zonal methods, the equation of the drying rate with the drying coefficient was used. The techniques of processing experimental data by zonal methods of A.V. Lykov, V. V. Krasnikov and by the method of B. S. Sazhin are described. The equation obtained by processing experimental data using the B. S. Sazhin method to determine the duration of the drying process contains only the amount of moisture content of the heating of the material, there is no need to know the critical moisture content. Dependences for calculating the drying coefficient by zonal methods are given. According to the results of the experiment, formulas for determining the duration of heat treatment of thermal insulation materials are presented. The dependence of the relative drying rate on the relative moisture content is presented as well. The processing of experimental data by generalized complex variables creates invariance conditions that allow moving from one variable to another, from one coordinate system to another, which reduces the number of experiments. Formulas with complex variables for determining the duration of drying of materials are given. Based on the drying kinetics equation by A. V. Lykov and the equation for the relative drying rate by G. K. Filonenko, equations are given for determining the density of heat fluxes, the intensity of moisture evaporation and temperature for the period of decreasing drying rate. Solutions of experimental equations are analyzed. The error caused by the processing of experimental data is established. Verification of the reliability of the empirical equations obtained is presented and comparison of the calculated values of the main parameters of the drying kinetics with the experiment is carried out.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78430126","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":"Optimization of Performance Characteristics of Magnetofluidic Seals for Wind Power Plants","authors":"O. N. Labkovich, S. G. Pogirnitskaya","doi":"10.21122/1029-7448-2023-66-1-80-90","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-80-90","url":null,"abstract":"The use of magnetofluidic seals are a promising direction in sealing rotating shafts of wind power plants. Magnetofluidic seals are characterized by high tightness, simplicity of the design, low losses by friction. Magnetic fluid seal of the rotating shaft consists of a ring magnet and two concentrators of magnetic field, forming with the shaft a narrow ring gap in which the magnetic fluid retained by magnetic field is a hermetic seal. Magnetic forces provide balance of volume of magnetic fluid under the impact of pressure drop and centrifugal forces. With an increase in the speed of rotation of the shaft up to 10 m/s, deformation of the free surface of the magnetic fluid at the surface of the shaft in the form of a funnel is visually observed, which causes a decrease in the retained pressure drop. As the rotation speed increases, the funnel increases, part of the magnetic fluid is ejected from the working area, the retained pressure drop decreases, and at 50 m/s there is a complete release of the magnetic fluid and depressurization of the seal. In order to increase the stability of the free surface of the magnetic fluid in the field of centrifugal forces, multilayer carbon nanotubes were introduced into it. They are characterized by a high specific surface area and, accordingly, a strong Van der Waals attraction. In a magnetic fluid, multilayer carbon nanotubes form structures which are oriented along the magnetic field lines. The following increase in the static load retained by a layer of magnetic fluid has been experimentally determined with the introduction of nanocarbon structures: when coinciding with the axis of the structures the increase was by 100 %, for the normal direction of the load to the axis of the structure – by 50 %. In the seal, with an increase in the shaft rotation speed, deformation of the free surface of a magnetic fluid with nanocarbon structures was observed at 18 m/s at a distance of 3 mm from the shaft surface. The pressure drop retained by the seal increased in the speed range of 10–40 m/s, the maximum effect of 50 % was obtained at a speed of 40 m/s. Thus, the introduction of nanocarbon structures into the magnetic fluid made it possible to reduce the influence of centrifugal forces on the retained pressure drop and increase the efficiency of the magnetofluidic seal at high speeds of rotation of the shaft of wind power plants.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74706064","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":"Assessment of Thermodynamic Efficiency of the Belarusian Energy System. Part 1","authors":"A. Bobich, Т. V. Ryzhova, T. V. Bubyr, V. Yanchuk, Y. S. Yatsukhna","doi":"10.21122/1029-7448-2023-66-1-44-56","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-44-56","url":null,"abstract":"The energy system is one of the foundations of a modern state, so, the need for its successful development and functioning is beyond doubt. In this regard, an objective assessment based on a set of indicators (viz. economic, energy and thermodynamic) is relevant. However, the traditional assessment of the operation of the energy system is carried out on the basis of such characteristics as the specific consumption of conventional fuel for electricity generation and heat release, which does not provide a comprehensive picture and is not always applied correctly. In this article, for the first time on the basis of the exergetic method, the calculation of the exergetic efficiency is considered. The use of this indicator makes it possible to obtain an objective assessment of the thermodynamic efficiency of such a complex formation as the energy system of a modern country in the easiest way. As an example, the unified energy system of Belarus in general and condensing power plants in particular have been analyzed for a fairly long period (2000–2021) and in various characteristic time periods. The method of calculating the exergetic efficiency is described. The results obtained are presented graphically. Attention is paid to the issue of the acceptability of the error when generalizing data on the initial flows of primary energy resources and product flows of centralized generating sources of the energy system. The contribution of condensing power plants to the total volume of electricity generation is analyzed, the most advanced of them are determined from a thermodynamic point of view. The calculation of their energy and exergetic indicators was carried out; the changes associated with the commissioning of the Belarusian NPP were considered. The conclusion is made that further reconstruction of energy sources of the power system in order to reduce the relative weight of natural gas in the incoming part of the energy balance to 50 % is expedient. This can be achieved by increasing the thermodynamic efficiency.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77286944","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 and Material Balance of Heliopyrolysis Device","authors":"G. Uzakov, A. V. Novik, X. Davlonov, X. Almardanov, S. E. Chuliev","doi":"10.21122/1029-7448-2023-66-1-57-65","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-57-65","url":null,"abstract":"","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79967203","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":"Assessment of the Efficiency of Thermal Waste Regeneration in the Blown Impassable Channels of Heating Mains","authors":"V. Sednin, T. V. Bubyr","doi":"10.21122/1029-7448-2023-66-1-30-43","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-30-43","url":null,"abstract":"To solve the problem of increasing the energy efficiency of thermal networks with heat pipelines located in impassable channels, a schematic and structural solution for the rational utilization of thermal waste generated during the transport of thermal energy has been developed. Due to the complexity of creating a full-scale experimental installation, a virtual experimental installation created by means of the Ansys software package was used in the study, on which an active numerical experiment was performed. Regression equations have been obtained for calculating the intensity of heat transfer from pipelines and channel enclosing structures with a given change in the size, length of channels and pipelines for various outdoor and ground temperatures characteristic of the heating and inter-heating periods. Statistical analysis, verification and validation of the obtained regression correlations were carried out, two-dimensional hypersurface crossections were obtained in the studied range of controlled factors. The results of numerical simulation of the operating modes of forced ventilation of impassable channels of heating mains with determination of the density of heat flows from the ground and mains water pipelines, air flow and the corresponding exhaust fan capacities have been presented. The following conditions in this case were accepted: the air flow rate is not higher than 8 m/s, the length of the heat pipeline section ensures the air temperature at the outlet of the channel at which there is no increase in heat losses from mains water pipelines to the ground under normal operating conditions of heating networks. The energy efficiency of heat utilization dissipated by mains water pipelines as well as ground cooling in impassable heating mains channels was investigated by intensifying their ventilation and using heat pump equipment at the end points of the channels for heating mains water, depending on the geometric characteristics of the heating mains section, air temperature, soil and mains water installations at central heating points or directly at heat sources. The potential of energy saving for district heating systems with various types of heat sources and the combined power system during the utilization of heat flows from the ground and heat pipelines laid in impassable channels has been identified. On the basis of the energy-saving potential, a technical and economic assessment was carried out and the conditions for the economic feasibility of implementing the proposed technical solution were determined.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"134 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86824608","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":"Operational Forecasting of Wind Speed for an Self-Contained Power Assembly of a Traction Substation","authors":"P. Matrenin, A. Khalyasmaa, A. Rusina, S. Eroshenko, N. A. Papkova, D. A. Sekatski","doi":"10.21122/1029-7448-2023-66-1-18-29","DOIUrl":"https://doi.org/10.21122/1029-7448-2023-66-1-18-29","url":null,"abstract":"Currently, the prospects of creating hybrid power assemblies using renewable energy sources, including wind energy, and energy storage systems based on hydrogen energy technologies are being considered. To control such an energy storage system, it is necessary to perform operational renewable sources generation forecasting, particularly forecasting of wind power assemblies. Their production depends on the speed and direction of the wind. The article presents the results of solving the problem of operational forecasting of wind speed for a hybrid power assembly project aimed at increasing the capacity of the railway section between Yaya and Izhmorskaya stations (Kemerovo region of the Russian Federation). Hourly data of wind speeds and directions for 15 years have been analyzed, a neural network model has been built, and a compact architecture of a multilayer perceptron has been proposed for short-term forecasting of wind speed and direction for 1 and 6 hours ahead. The model that has been developed allows minimizing the risks of overfitting and loss of forecasting accuracy due to changes in the operating conditions of the model over time. A specific feature of this work is the stability investigation of the model trained on the data of long-term observations to long-term changes, as well as the analysis of the possibilities of improving the accuracy of forecasting due to regular further training of the model on newly available data. The nature of the influence of the size of the training sample and the self-adaptation of the model on the accuracy of forecasting and the stability of its work on the horizon of several years has been established. It is shown that in order to ensure high accuracy and stability of the neural network model of wind speed forecasting, long-term meteorological observations data are required.","PeriodicalId":52141,"journal":{"name":"Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83644448","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}