Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.08
P. Matrenin, M. Safaraliev, N. Kiryanova, S. Sultonov
Energy prices and сost of materials for solar and wind power plants have increased over the past year. Therefore, significance increases for the hydropower and long-term (1–10 years) planning generation for the existing hydropower plants, which requires forecasting the average monthly values of the river flow. This task is especially urgent for countries without their own oil-fields and opportunity to invest in the creation of solar or wind power plants. The aim of the research is to decrease the mean absolute forecasting error of the long-term prediction for the Vakhsh River flow (Tajikistan) based on the long-term observations. A study of existing methods for the river runoff forecasting in relation to the object under consideration was carried out, and a new transformation model for the space of the input features was developed. The most significant results are the decrease in the average forecast error in the Vakhsh river flow achieved by the use of the proposed space of polynomial logarithmic features in comparison with other methods, and the need to use at least the 20 year-old observational data for the long-term operation planning of the hydropower plants and cascades of the hydropower plants obtained from the results of computational experiments. The significance of the results lies in the fact that a new approach to the long-term forecasting of river flow has been proposed and verified using the long-term observations. This approach does not require the use of the long-term meteorological forecasts, which are not possible to obtain with high accuracy for all regions.
{"title":"Monthly Runoff Forecasting by Non-Generalizing Machine Learning Model and Feature Space Transformation (Vakhsh River Case Study)","authors":"P. Matrenin, M. Safaraliev, N. Kiryanova, S. Sultonov","doi":"10.52254/1857-0070.2022.3-55.08","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.08","url":null,"abstract":"Energy prices and сost of materials for solar and wind power plants have increased over the past year. Therefore, significance increases for the hydropower and long-term (1–10 years) planning generation for the existing hydropower plants, which requires forecasting the average monthly values of the river flow. This task is especially urgent for countries without their own oil-fields and opportunity to invest in the creation of solar or wind power plants. The aim of the research is to decrease the mean absolute forecasting error of the long-term prediction for the Vakhsh River flow (Tajikistan) based on the long-term observations. A study of existing methods for the river runoff forecasting in relation to the object under consideration was carried out, and a new transformation model for the space of the input features was developed. The most significant results are the decrease in the average forecast error in the Vakhsh river flow achieved by the use of the proposed space of polynomial logarithmic features in comparison with other methods, and the need to use at least the 20 year-old observational data for the long-term operation planning of the hydropower plants and cascades of the hydropower plants obtained from the results of computational experiments. The significance of the results lies in the fact that a new approach to the long-term forecasting of river flow has been proposed and verified using the long-term observations. This approach does not require the use of the long-term meteorological forecasts, which are not possible to obtain with high accuracy for all regions.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49080600","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.07
N. Kuznetsov, O. Lysenko
The purpose of the article is to study the possibilities of preventing the imbalance caused by the stochastic nature of RES by regulating the electricity accumulation and the backup generator. The subject of the research is random processes of energy generation and consumption. The goal is achieved by a mathematical model construction in which the system parameters would be formalized and allow the choice of optimal options. The mathematical model uses random functions to obtain statistical estimates, and is implemented as sequential models of energy generation and consumption as an integrated random process. The models’ adequacy is confirmed by comparing the simulated and real indicators for a number of existing RES in Ukraine. The proposed approach made it possible to establish the presence of system parameters that minimize energy losses and consumption, reduce the probability of energy imbalance, and effectively use the reserve power. The proposed mathematical model allows determining the probability of various system states, it estimates the reliability of energy supply, and minimizes losses at the stages of designing a power system and planning its operating modes. The above estimates are typical for certain climatic conditions and modes of energy consumption, and are of a specific nature. The significance of the work lies in the fact that the proposed formulation of the problem makes it possible to adapt the mathematical model to various conditions, to find implicit dependencies between the technical parameters of the system and its indicators in order to find optimal solutions.
{"title":"Determination of the Optimal Algorithm for the Operation of a Hybrid Power System with a Regulating Generator","authors":"N. Kuznetsov, O. Lysenko","doi":"10.52254/1857-0070.2022.3-55.07","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.07","url":null,"abstract":"The purpose of the article is to study the possibilities of preventing the imbalance caused by the stochastic nature of RES by regulating the electricity accumulation and the backup generator. The subject of the research is random processes of energy generation and consumption. The goal is achieved by a mathematical model construction in which the system parameters would be formalized and allow the choice of optimal options. The mathematical model uses random functions to obtain statistical estimates, and is implemented as sequential models of energy generation and consumption as an integrated random process. The models’ adequacy is confirmed by comparing the simulated and real indicators for a number of existing RES in Ukraine. The proposed approach made it possible to establish the presence of system parameters that minimize energy losses and consumption, reduce the probability of energy imbalance, and effectively use the reserve power. The proposed mathematical model allows determining the probability of various system states, it estimates the reliability of energy supply, and minimizes losses at the stages of designing a power system and planning its operating modes. The above estimates are typical for certain climatic conditions and modes of energy consumption, and are of a specific nature. The significance of the work lies in the fact that the proposed formulation of the problem makes it possible to adapt the mathematical model to various conditions, to find implicit dependencies between the technical parameters of the system and its indicators in order to find optimal solutions.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47232464","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.12
V. Chistov, I. Zakharchenko, V. Pavlenko, M. Pavlenko, P. Berdnik, A. Timochko, K. Kryzhevskaya
The purpose of this work is the development of mathematical tools for formalizing decisionmaking problems in open expert real-time control systems. The goal was achieved by defining and formally describing all the elements of a formal system. The most significant result was the proposed approach to formalization. With its help, within the framework of a single formalism, the dynamic properties of the subject area and the logical-analytical activity of the power system dispatcher, presented in different classes of formal logics, were described. The significance of the results obtained lies in the possibility of a rigorous description of various aspects of knowledge within the framework of a single formal apparatus with further pragmatic interpretation in the management process. The proposed approach was distinguished by using the axioms of aletic and deontic logics and the development of axioms that reflect the specifics of the problems being solved. The introduced system of basic concepts and relations makes it possible to classify many decision-making problems for the power systems management. The goals were described within the framework of a single formalism form the basis of the apparatus for formalizing the decision-making problems of the class under consideration. The formalization apparatus provides a description of the dynamic properties of the system within each aspect of knowledge of the content paradigm. The direction of further research is the construction of an appropriate formal theory based on the proposed formal system.
{"title":"Using the Mathematical Apparatus of Cellular Automata to Solve the Problem of Monitoring Critical Infrastructure Objects by Unmanned Aerial Vehicles","authors":"V. Chistov, I. Zakharchenko, V. Pavlenko, M. Pavlenko, P. Berdnik, A. Timochko, K. Kryzhevskaya","doi":"10.52254/1857-0070.2022.3-55.12","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.12","url":null,"abstract":"The purpose of this work is the development of mathematical tools for formalizing decisionmaking problems in open expert real-time control systems. The goal was achieved by defining and formally describing all the elements of a formal system. The most significant result was the proposed approach to formalization. With its help, within the framework of a single formalism, the dynamic properties of the subject area and the logical-analytical activity of the power system dispatcher, presented in different classes of formal logics, were described. The significance of the results obtained lies in the possibility of a rigorous description of various aspects of knowledge within the framework of a single formal apparatus with further pragmatic interpretation in the management process. The proposed approach was distinguished by using the axioms of aletic and deontic logics and the development of axioms that reflect the specifics of the problems being solved. The introduced system of basic concepts and relations makes it possible to classify many decision-making problems for the power systems management. The goals were described within the framework of a single formalism form the basis of the apparatus for formalizing the decision-making problems of the class under consideration. The formalization apparatus provides a description of the dynamic properties of the system within each aspect of knowledge of the content paradigm. The direction of further research is the construction of an appropriate formal theory based on the proposed formal system.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48854124","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.02
V. Oleschuk
The purpose of this work is to modernize the control scheme of a transformer-based photovoltaic system with three inverters controlled by the modified algorithms of synchronous spacevector PWM in order to ensure linear regulation of the system in the overmodulation zone of the inverter block in the process of forming a symmetrical and synchronized (with the operating frequency of the system) voltage on the inverter-side windings of a power transformer. This goal is achieved by the fact that the process of two-stage control of the system in the zone of overmodulation of inverters is carried out on the basis of synchronized phase shifts between the control signals of inverters (a constant phase shift, as well as an additional adjustable phase shift between the inverter signals as a function of the duration of clock subintervals), with an appropriate modification of the algorithms of synchronous PWM of inverters due to the inclusion of two specialized correction factors in the basic functional dependencies. The most significant results of the work include the fact that in a system with a modified control scheme and modulation of the inverter block in the overmodulation zone, the resulting voltage on the inverter-side windings of the power transformer is characterized by quarterwave symmetry, and its spectrum contains no even-order harmonics, as well as subharmonics, including regimes of fluctuations in the operating frequency of the system connected to a three-phase network, thereby helping to reduce losses in the transformer windings and improve the efficiency of photovoltaic systems.
{"title":"Analysis and Simulation of Overmodulation Modes of a Three-Inverter Block of the Photovoltaic Installation","authors":"V. Oleschuk","doi":"10.52254/1857-0070.2022.3-55.02","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.02","url":null,"abstract":"The purpose of this work is to modernize the control scheme of a transformer-based photovoltaic system with three inverters controlled by the modified algorithms of synchronous spacevector PWM in order to ensure linear regulation of the system in the overmodulation zone of the inverter block in the process of forming a symmetrical and synchronized (with the operating frequency of the system) voltage on the inverter-side windings of a power transformer. This goal is achieved by the fact that the process of two-stage control of the system in the zone of overmodulation of inverters is carried out on the basis of synchronized phase shifts between the control signals of inverters (a constant phase shift, as well as an additional adjustable phase shift between the inverter signals as a function of the duration of clock subintervals), with an appropriate modification of the algorithms of synchronous PWM of inverters due to the inclusion of two specialized correction factors in the basic functional dependencies. The most significant results of the work include the fact that in a system with a modified control scheme and modulation of the inverter block in the overmodulation zone, the resulting voltage on the inverter-side windings of the power transformer is characterized by quarterwave symmetry, and its spectrum contains no even-order harmonics, as well as subharmonics, including regimes of fluctuations in the operating frequency of the system connected to a three-phase network, thereby helping to reduce losses in the transformer windings and improve the efficiency of photovoltaic systems.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41450949","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.01
S. Goolak, M. Kyrychenko
The aim of research is to develop a thermal model of the output converter of an electric locomotive with vector control, taking into account the operating modes of the electric locomotive. The aim was achieved by using energy losses at the moments of switching functions that describe the nature of the change in the curves of currents and power voltages of transistors and converter diodes. The object of research is an autonomous voltage converter, which is part of the traction drive of an electric locomotive with a vector control system. The simulation was carried out for an autonomous voltage converter, the load of which is two traction induction motors operating in the nominal mode. The temperature of transistors and diodes is obtained for the established modes of operation of traction motors. The most important results are the analytical dependence of thermal power losses in the inverter as a function of inverter phase currents and voltages. The significance of the results obtained is to establish the dependence of the temperature of the power devices of the inverter on the actual operating conditions of the electric locomotive. The established dependencies will further determine the spectral power of thermal noise. This will allow, when designing a traction drive control system, to develop an effective system for filtering thermal noise. This will increase the energy performance of the traction drive of the electric locomotive by improving the accuracy of regulation.
{"title":"Thermal Model of the Output Traction Converter of an Electric Locomotive with Induction Motors","authors":"S. Goolak, M. Kyrychenko","doi":"10.52254/1857-0070.2022.3-55.01","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.01","url":null,"abstract":"The aim of research is to develop a thermal model of the output converter of an electric locomotive with vector control, taking into account the operating modes of the electric locomotive. The aim was achieved by using energy losses at the moments of switching functions that describe the nature of the change in the curves of currents and power voltages of transistors and converter diodes. The object of research is an autonomous voltage converter, which is part of the traction drive of an electric locomotive with a vector control system. The simulation was carried out for an autonomous voltage converter, the load of which is two traction induction motors operating in the nominal mode. The temperature of transistors and diodes is obtained for the established modes of operation of traction motors. The most important results are the analytical dependence of thermal power losses in the inverter as a function of inverter phase currents and voltages. The significance of the results obtained is to establish the dependence of the temperature of the power devices of the inverter on the actual operating conditions of the electric locomotive. The established dependencies will further determine the spectral power of thermal noise. This will allow, when designing a traction drive control system, to develop an effective system for filtering thermal noise. This will increase the energy performance of the traction drive of the electric locomotive by improving the accuracy of regulation.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42832873","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.03
A. Morozov, Ju.B. Kazakov, N. Morozov, S. Nesterov
The objectives of the work are to develop a non-contact method of detecting internal electromagnetic defects in synchronous generators based on the analysis of asymmetry of the external magnetic field distribution resulting from damage, establishing the relationship of defects of a generator with the pattern of field distribution, identifying diagnostic signs for the defects. These objectives are achieved by developing and using three-dimensional finite-element models of the external magnetic field of synchronous generators, by studying and analyzing the results of numerical simulation of external magnetic fields, by comparing the simulation results with experimental data. Significant results of the work include the improvement of the non-contact method for detecting internal electromagnetic defects in synchronous generators, revealing how defects of the generator manifest themselves in the asymmetry of magnetic field distribution, and detecting the correlation of field asymmetry with the type and severity of defects. For implicit-pole synchronous generators, it is reasonable to use the field asymmetry coefficient determined by the shift in the magnetic field distribution caused by field coils damage. The sign of the coefficient indicates the pole with a damaged field coil. The value of the coefficient characterizes the severity of damage to the field coils, with a critical value of 0.1. The significance of the results lies in the possibility of timely and non-contact diagnostics of internal electromagnetic defects of implicitpole synchronous generators, which can significantly reduce the economic damage from failures of generators without installation of diagnostic sensors of damage inside the generators.
{"title":"Identification of Internal Electromagnetic Defects of Implicit-Pole Synchronous Generators Based on the Information of its External Magnetic","authors":"A. Morozov, Ju.B. Kazakov, N. Morozov, S. Nesterov","doi":"10.52254/1857-0070.2022.3-55.03","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.03","url":null,"abstract":"The objectives of the work are to develop a non-contact method of detecting internal electromagnetic defects in synchronous generators based on the analysis of asymmetry of the external magnetic field distribution resulting from damage, establishing the relationship of defects of a generator with the pattern of field distribution, identifying diagnostic signs for the defects. These objectives are achieved by developing and using three-dimensional finite-element models of the external magnetic field of synchronous generators, by studying and analyzing the results of numerical simulation of external magnetic fields, by comparing the simulation results with experimental data. Significant results of the work include the improvement of the non-contact method for detecting internal electromagnetic defects in synchronous generators, revealing how defects of the generator manifest themselves in the asymmetry of magnetic field distribution, and detecting the correlation of field asymmetry with the type and severity of defects. For implicit-pole synchronous generators, it is reasonable to use the field asymmetry coefficient determined by the shift in the magnetic field distribution caused by field coils damage. The sign of the coefficient indicates the pole with a damaged field coil. The value of the coefficient characterizes the severity of damage to the field coils, with a critical value of 0.1. The significance of the results lies in the possibility of timely and non-contact diagnostics of internal electromagnetic defects of implicitpole synchronous generators, which can significantly reduce the economic damage from failures of generators without installation of diagnostic sensors of damage inside the generators.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44334871","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.9
O. Burdo, S. Terziev, A. Burdo, I. Sirotyuk, E.A. Pylypenko, A. Akimov, M.Yu. Molchanov
The aim of this work is the energy-efficient equipment creation for production of a highquality dry product from a plant raw material and development of scientific and engineering foundation for the design of such an equipment. The achievement of this aim lies in a deep analysis of tendency in the development of a drying theory and technique. The graph is presented, on the basis of which the development of heat and moisture transfer model of A.V. Lykov is given, taking into account the P. A. Rebinder moisture bond forms specificity. The problems of convective drying modern technologies are determined; the reasons of high-energy consumption during their work are substantiated. The electrodynamic dehydrators classification is given, which consideres the combined simple modes (drying) and hybrid dehydration modes. On the basis of the first law of thermodynamics, the possibility of a significant decrease in energy consumption is shown by the organization of a “vapordynamic” effect. The most significant result of the work is the construction of the electrodynamic apparatus module for dehydration of food and medicinal plant raw material. By the combination of electromagnetic field with the filtration process the specific energy consumptions were 1.9 MJ per 1 kg of the removed moisture, at the hybrid processes — juice yield exceeded vapor yield by 3.5 times. The significance of the work consists in the fact that the scientific conception of the authors on the possibilities of the significant decrease in energy consumption during the raw material dehydration at the innovative electrodynamic type apparatuses was practically proven.
{"title":"Energetics and Kinetics of Plant Raw Material Dehydration Processes","authors":"O. Burdo, S. Terziev, A. Burdo, I. Sirotyuk, E.A. Pylypenko, A. Akimov, M.Yu. Molchanov","doi":"10.52254/1857-0070.2022.3-55.9","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.9","url":null,"abstract":"The aim of this work is the energy-efficient equipment creation for production of a highquality dry product from a plant raw material and development of scientific and engineering foundation for the design of such an equipment. The achievement of this aim lies in a deep analysis of tendency in the development of a drying theory and technique. The graph is presented, on the basis of which the development of heat and moisture transfer model of A.V. Lykov is given, taking into account the P. A. Rebinder moisture bond forms specificity. The problems of convective drying modern technologies are determined; the reasons of high-energy consumption during their work are substantiated. The electrodynamic dehydrators classification is given, which consideres the combined simple modes (drying) and hybrid dehydration modes. On the basis of the first law of thermodynamics, the possibility of a significant decrease in energy consumption is shown by the organization of a “vapordynamic” effect. The most significant result of the work is the construction of the electrodynamic apparatus module for dehydration of food and medicinal plant raw material. By the combination of electromagnetic field with the filtration process the specific energy consumptions were 1.9 MJ per 1 kg of the removed moisture, at the hybrid processes — juice yield exceeded vapor yield by 3.5 times. The significance of the work consists in the fact that the scientific conception of the authors on the possibilities of the significant decrease in energy consumption during the raw material dehydration at the innovative electrodynamic type apparatuses was practically proven.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46988381","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}
Pub Date : 2022-08-01DOI: 10.52254/1857-0070.2022.3-55.04
V. Prokhorov, V. Kirichkov, S. Chernov, N. Fomenko
The M-shaped boiler construction for the advanced ultrasupercritical steam parameters (A-USC) is proposed in this work. The boiler was designed to operate in a 500 MW unit on low volatile hard coal. This design allows reducing the pipelines length of the high cost steam pipelines made of nickel alloys. A downstream (invert) furnace is offered for this boiler type. The coal dust burning scheme design using the direct-flow burners and nozzles in a system of vertical and horizontal tangential torches and the solid ash removal are proposed. This approach was extensively used earlier on standard shaped boilers, and it was upgraded now for an invert furnace. The goals are achieved by conducting research on the physical furnace model and thermal furnace processes numerical simulation by computational fluid dynamics software. The most significant research results were as follows: the oxidizer stage supply was performed along the torch length and furnace height; the dynamic jet pressure on the furnace walls was excluded; a high degree of coal burnout was ensured due to the vortex furnace aerodynamics implementation; the uniform furnace section filling with air jets was performed; turbulent jets ejection was significantly higher than that for a flat submerged jet; chemical underburning loss did not exceed 0.1%; and unburned carbon loss was 0.8%. The carbon monoxide concentration at the furnace outlet in terms of air excess ratio equal to α=1.4 was 226 mg/nm3 . The nitrogen oxides concentration in the flue gases (normalized) was 424 mg/nm3 . The results significance obtained during the research is efficient solid fuel use with high technical and economic boiler performance.
{"title":"The Coal Dust Combustion Scheme for an Invert Furnace of an A-USC M-Shaped Boiler","authors":"V. Prokhorov, V. Kirichkov, S. Chernov, N. Fomenko","doi":"10.52254/1857-0070.2022.3-55.04","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.3-55.04","url":null,"abstract":"The M-shaped boiler construction for the advanced ultrasupercritical steam parameters (A-USC) is proposed in this work. The boiler was designed to operate in a 500 MW unit on low volatile hard coal. This design allows reducing the pipelines length of the high cost steam pipelines made of nickel alloys. A downstream (invert) furnace is offered for this boiler type. The coal dust burning scheme design using the direct-flow burners and nozzles in a system of vertical and horizontal tangential torches and the solid ash removal are proposed. This approach was extensively used earlier on standard shaped boilers, and it was upgraded now for an invert furnace. The goals are achieved by conducting research on the physical furnace model and thermal furnace processes numerical simulation by computational fluid dynamics software. The most significant research results were as follows: the oxidizer stage supply was performed along the torch length and furnace height; the dynamic jet pressure on the furnace walls was excluded; a high degree of coal burnout was ensured due to the vortex furnace aerodynamics implementation; the uniform furnace section filling with air jets was performed; turbulent jets ejection was significantly higher than that for a flat submerged jet; chemical underburning loss did not exceed 0.1%; and unburned carbon loss was 0.8%. The carbon monoxide concentration at the furnace outlet in terms of air excess ratio equal to α=1.4 was 226 mg/nm3 . The nitrogen oxides concentration in the flue gases (normalized) was 424 mg/nm3 . The results significance obtained during the research is efficient solid fuel use with high technical and economic boiler performance.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45397362","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}
Pub Date : 2022-05-01DOI: 10.52254/1857-0070.2022.2-54.05
N. Ivancha, V. Vishnyakov, I. Muravieva, V. Shcherbachev, E. Ermolina
The purpose of this study was to develop a calculation tool for researchers and technologists - metallurgists, providing the ability to quickly assess the distribution of charge materials in a blast furnace when it is loaded with a multicomponent charge. The goal is achieved by analyzing and summarizing the multidimensional matrix of values for the content of the charge components in the annular zones of the blast furnace, obtained using a mathematical model of its loading under various modes, changing the content of pellets in the charge and the moment the pellets are unloaded onto the main conveyor. The most important results of the studies carried out are the substantiation of the possibility of obtaining and applying calculated dependencies to determine the characteristics of the distribution of charge components with an accuracy acceptable for technological practice, as well as the established relationship between the content of the component in the charge and the value of the set point for the start of unloading it onto the conveyor with the content of this component in the annular zones of the top. Estimated composition of mixtures of charge materials formed in different zones of a blast furnace makes it possible to predict the properties of melts formed from them and to correct them in order to achieve the required level of energy efficiency in melting a multicomponent charge by promptly choosing rational parameters of the loading mode.
{"title":"Increasing the Energy Efficiency of Blast-Furnace Smelting by Choosing Rational Parameters for Loading a Multicomponent Charge","authors":"N. Ivancha, V. Vishnyakov, I. Muravieva, V. Shcherbachev, E. Ermolina","doi":"10.52254/1857-0070.2022.2-54.05","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.2-54.05","url":null,"abstract":"The purpose of this study was to develop a calculation tool for researchers and technologists - metallurgists, providing the ability to quickly assess the distribution of charge materials in a blast furnace when it is loaded with a multicomponent charge. The goal is achieved by analyzing and summarizing the multidimensional matrix of values for the content of the charge components in the annular zones of the blast furnace, obtained using a mathematical model of its loading under various modes, changing the content of pellets in the charge and the moment the pellets are unloaded onto the main conveyor. The most important results of the studies carried out are the substantiation of the possibility of obtaining and applying calculated dependencies to determine the characteristics of the distribution of charge components with an accuracy acceptable for technological practice, as well as the established relationship between the content of the component in the charge and the value of the set point for the start of unloading it onto the conveyor with the content of this component in the annular zones of the top. Estimated composition of mixtures of charge materials formed in different zones of a blast furnace makes it possible to predict the properties of melts formed from them and to correct them in order to achieve the required level of energy efficiency in melting a multicomponent charge by promptly choosing rational parameters of the loading mode.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42557628","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}
Pub Date : 2022-05-01DOI: 10.52254/1857-0070.2022.2-54.08
A. Kobozeva, A. Sokolov
In view of the high compatibility of the Walsh-Hadamard transform to the architecture of modern computing facilities, it is sensible to use it in methods of steganography and steganalysis. Now, there are some efficient steganographic methods that use the Walsh-Hadamard transform domain for information embedding presented in the literature. It is known that to ensure the reliability of the steganographic message perception, information should be embedded in its high-frequency components; nevertheless, the issues of the correspondence of the Walsh-Hadamard transformants to the frequency components of the original matrix of the cover image are poorly researched. The purpose of this paper is to develop a formal sufficient condition for ensuring the reliability of perception of steganographic messages in the Walsh-Hadamard transform domain. This purpose was achieved by establishing the relationship between the Walsh-Hadamard transformants and the discrete cosine transform transformants, which was theoretically substantiated in two ways, and also experimentally confirmed. Based on the established relationship between the Walsh-Hadamard transform and the discrete cosine transform, as well as the components of the singular value decomposition of the corresponding matrices, a sufficient condition has been developed to ensure the reliability of the perception of steganographic messages in the Walsh-Hadamard transform domain. The sufficient condition consists in the fact that after embedding of additional information using any steganographic method, those WalshHadamard transformants that correspond to the singular triples of the matrix corresponding to small (smallest) in value singular numbers, should change.
{"title":"The Sufficient Condition for Ensuring the Reliability of Perception of the Steganographic Message in the Walsh-Hadamard Transform Domain","authors":"A. Kobozeva, A. Sokolov","doi":"10.52254/1857-0070.2022.2-54.08","DOIUrl":"https://doi.org/10.52254/1857-0070.2022.2-54.08","url":null,"abstract":"In view of the high compatibility of the Walsh-Hadamard transform to the architecture of modern computing facilities, it is sensible to use it in methods of steganography and steganalysis. Now, there are some efficient steganographic methods that use the Walsh-Hadamard transform domain for information embedding presented in the literature. It is known that to ensure the reliability of the steganographic message perception, information should be embedded in its high-frequency components; nevertheless, the issues of the correspondence of the Walsh-Hadamard transformants to the frequency components of the original matrix of the cover image are poorly researched. The purpose of this paper is to develop a formal sufficient condition for ensuring the reliability of perception of steganographic messages in the Walsh-Hadamard transform domain. This purpose was achieved by establishing the relationship between the Walsh-Hadamard transformants and the discrete cosine transform transformants, which was theoretically substantiated in two ways, and also experimentally confirmed. Based on the established relationship between the Walsh-Hadamard transform and the discrete cosine transform, as well as the components of the singular value decomposition of the corresponding matrices, a sufficient condition has been developed to ensure the reliability of the perception of steganographic messages in the Walsh-Hadamard transform domain. The sufficient condition consists in the fact that after embedding of additional information using any steganographic method, those WalshHadamard transformants that correspond to the singular triples of the matrix corresponding to small (smallest) in value singular numbers, should change.","PeriodicalId":41974,"journal":{"name":"Problemele Energeticii Regionale","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43943417","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}
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