Pub Date : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-5-15
Y. Rumiantsev, F. Romaniuk, V. Rumiantsev
In microprocessor automation and control systems, the amplitude (effective) values of the fundamental harmonic of the input signals are widely used as information parameters of the controlled quantities. They are most often determined by samples of one or a pair of orthogonal components of the signal, for the formation of which digital Fourier filters and their modifications are mainly used. At the rated frequency in the power system, these filters ensure reliable reception of the signal amplitude without additional error. If the frequency deviates from the rated one, the number of samples per signal period is not an integer and the discretization becomes asynchronous. As a result, a corresponding error appears in the amplitude of the signal, and its change becomes oscillating. With minor frequency fluctuations in the normal mode, the amplitude error is insignificant. However, in abnormal situations, the frequency can have significant variations. At the same time, in critical situations, failure of automation and control systems, as well as incorrect operation of their functional algorithms, cannot be excluded. Known methods for determining the amplitude of a signal with frequency fluctuations provide a solution to the existing problem, but they are characterized by a slow response. The proposed high-response method for determining the amplitude during frequency fluctuations is focused on using as initial information samples of instantaneous values of the cosine orthogonal component of the signal, which are formed using an appropriate digital Fourier filter. Based on these samples, the dynamic cosine and sine of the angle of one sample are calculated, the use of which in calculating the amplitude ensures its independence from frequency. Processing of the received amplitude with an amplifying element with a nonlinear coefficient makes it possible to achieve acceptable performance. The effectiveness of the proposed solution was evaluated by a computational experiment using a digital model implemented in the MATLAB-Simulink dynamic modeling environment. In this case, both sinusoidal input signals and complex ones, close to the real secondary signals of measuring transformers, were used as test actions. As a result of the research, it was found that the proposed method for determining the amplitude during frequency fluctuations has a performance at the level of a quarter of the period and provides effective elimination of frequency error both in load modes and in damage modes.
{"title":"A Fast-Response Method for Determining the Amplitude of a Signal in Microprocessor Automation and Control Systems with Frequency Fluctuations","authors":"Y. Rumiantsev, F. Romaniuk, V. Rumiantsev","doi":"10.21122/1029-7448-2024-67-1-5-15","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-5-15","url":null,"abstract":"In microprocessor automation and control systems, the amplitude (effective) values of the fundamental harmonic of the input signals are widely used as information parameters of the controlled quantities. They are most often determined by samples of one or a pair of orthogonal components of the signal, for the formation of which digital Fourier filters and their modifications are mainly used. At the rated frequency in the power system, these filters ensure reliable reception of the signal amplitude without additional error. If the frequency deviates from the rated one, the number of samples per signal period is not an integer and the discretization becomes asynchronous. As a result, a corresponding error appears in the amplitude of the signal, and its change becomes oscillating. With minor frequency fluctuations in the normal mode, the amplitude error is insignificant. However, in abnormal situations, the frequency can have significant variations. At the same time, in critical situations, failure of automation and control systems, as well as incorrect operation of their functional algorithms, cannot be excluded. Known methods for determining the amplitude of a signal with frequency fluctuations provide a solution to the existing problem, but they are characterized by a slow response. The proposed high-response method for determining the amplitude during frequency fluctuations is focused on using as initial information samples of instantaneous values of the cosine orthogonal component of the signal, which are formed using an appropriate digital Fourier filter. Based on these samples, the dynamic cosine and sine of the angle of one sample are calculated, the use of which in calculating the amplitude ensures its independence from frequency. Processing of the received amplitude with an amplifying element with a nonlinear coefficient makes it possible to achieve acceptable performance. The effectiveness of the proposed solution was evaluated by a computational experiment using a digital model implemented in the MATLAB-Simulink dynamic modeling environment. In this case, both sinusoidal input signals and complex ones, close to the real secondary signals of measuring transformers, were used as test actions. As a result of the research, it was found that the proposed method for determining the amplitude during frequency fluctuations has a performance at the level of a quarter of the period and provides effective elimination of frequency error both in load modes and in damage modes.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"43 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139780115","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-33-49
G. Kulakov, N. V. Voyush
Steam temperature control significantly affects the efficiency, reliability and durability of steam boilers. In the article, special attention is paid to substantiating the relevance of a significant increase in the efficiency of steam boiler injection regulators operating in a wide range of load changes. It is indicated that one of the main directions of solving this problem is the use of optimal regulators with dynamic compensation and combined principles of regulation for deviation and perturbation at the same time. A combined automatic control system is proposed with full invariance with respect to the most dangerous measured internal disturbance and with partial invariance when working out an external disturbance with specified permissible deviations of the controlled parameter. At the same time, in order to improve the quality of regulation under the main influences, it is proposed to carry out optimization with the use of the transfer functions of the leading and main sections of the control object as well as to turn the internal contour of the two-circuit system into an amplifier with a single transmission coefficient when working out the corrective action. Also, it is proposed to form the structure of the corrective regulator on the basis of the principle of dynamic compensation for objects with a conditional delay along the channel of regulatory action, which makes it possible to ensure the specified quality of regulation when working out the control action surge. Thus, a significant increase in speed and accuracy is achieved when working out internal and external measured disturbances compared to a typical two-circuit system or an invariant automatic control system with an internal model, which makes it possible to recommend the proposed invariant cascade automatic control system for widespread implementation in the field of automation of thermal power processes.
{"title":"Structural and Parametric Optimization of Steam Boiler Injection Regulators","authors":"G. Kulakov, N. V. Voyush","doi":"10.21122/1029-7448-2024-67-1-33-49","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-33-49","url":null,"abstract":"Steam temperature control significantly affects the efficiency, reliability and durability of steam boilers. In the article, special attention is paid to substantiating the relevance of a significant increase in the efficiency of steam boiler injection regulators operating in a wide range of load changes. It is indicated that one of the main directions of solving this problem is the use of optimal regulators with dynamic compensation and combined principles of regulation for deviation and perturbation at the same time. A combined automatic control system is proposed with full invariance with respect to the most dangerous measured internal disturbance and with partial invariance when working out an external disturbance with specified permissible deviations of the controlled parameter. At the same time, in order to improve the quality of regulation under the main influences, it is proposed to carry out optimization with the use of the transfer functions of the leading and main sections of the control object as well as to turn the internal contour of the two-circuit system into an amplifier with a single transmission coefficient when working out the corrective action. Also, it is proposed to form the structure of the corrective regulator on the basis of the principle of dynamic compensation for objects with a conditional delay along the channel of regulatory action, which makes it possible to ensure the specified quality of regulation when working out the control action surge. Thus, a significant increase in speed and accuracy is achieved when working out internal and external measured disturbances compared to a typical two-circuit system or an invariant automatic control system with an internal model, which makes it possible to recommend the proposed invariant cascade automatic control system for widespread implementation in the field of automation of thermal power processes.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"55 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139839795","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-50-65
Yu. P. Yarmolchick, R. Schröger, H. Haberfelner, M. Pichler, D. Kostić, G. V. Moroz
To solve the problem of useful utilization (by combustion in heat generators) of liquid and gaseous industrial waste (that was defined in Part 1 of the present article), heat transfer processes in heat generating units were considered in Part 2. The main equipment for the effective solution of this process is a burner device and a combustion chamber with heat transfer to an external heat carrier, for example, a boiler furnace or a heat recovery boiler. The present article considers an example of calculating such a process for a distinctive mixture of waste from a chemical industry enterprise using modeling of possible schemes of a flame combustion system for a characteristic combination of various types of gaseous and liquid combustible products. For this purpose, the CFD (Computational Fluid Dynamics) computational hydrodynamics method was applied, which is determined to be the most effective one, in analyzing the behavior of media flows and combustion processes. CFD analysis makes it possible to predict hydrodynamic and thermal processes (especially in complex multicomponent systems) and optimize them to achieve the best results. The most important factor in high-quality combustion is the atomization process (fine atomization) of highly viscous liquids with high surface tension coefficients. The ultrasonic me-thod has been adopted as the most effective for such liquids. Besides, the quality of the distribution of flows of combustion mixtures and flue gases in the combustion chamber is considered. For doing this, it is necessary to arrange separate flows of axial and peripheral air, which make it possible not only to change the configuration of the flame, but also to direct convective flue gas flows to the most efficient areas of the combustion chamber. The article considers various options for heat transfer (convective and radial) depending on various factors, taking into account the degree of probability of formation of pollutants (primarily NOx) in combustion products. The results of the numerical solution of the problem are presented. The analysis of the results on the optimal ratio of the shares of primary and secondary air flows for combustion was carried out. In conclusion, a comparative analysis of the options for burning fuel directly in the boiler and in the pre-combustion chamber is presented. The efficiency of direct combustion has been demonstrated.
{"title":"Combined Combustion of Various Industrial Waste Flows in Boiler Furnaces. Part 3","authors":"Yu. P. Yarmolchick, R. Schröger, H. Haberfelner, M. Pichler, D. Kostić, G. V. Moroz","doi":"10.21122/1029-7448-2024-67-1-50-65","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-50-65","url":null,"abstract":"To solve the problem of useful utilization (by combustion in heat generators) of liquid and gaseous industrial waste (that was defined in Part 1 of the present article), heat transfer processes in heat generating units were considered in Part 2. The main equipment for the effective solution of this process is a burner device and a combustion chamber with heat transfer to an external heat carrier, for example, a boiler furnace or a heat recovery boiler. The present article considers an example of calculating such a process for a distinctive mixture of waste from a chemical industry enterprise using modeling of possible schemes of a flame combustion system for a characteristic combination of various types of gaseous and liquid combustible products. For this purpose, the CFD (Computational Fluid Dynamics) computational hydrodynamics method was applied, which is determined to be the most effective one, in analyzing the behavior of media flows and combustion processes. CFD analysis makes it possible to predict hydrodynamic and thermal processes (especially in complex multicomponent systems) and optimize them to achieve the best results. The most important factor in high-quality combustion is the atomization process (fine atomization) of highly viscous liquids with high surface tension coefficients. The ultrasonic me-thod has been adopted as the most effective for such liquids. Besides, the quality of the distribution of flows of combustion mixtures and flue gases in the combustion chamber is considered. For doing this, it is necessary to arrange separate flows of axial and peripheral air, which make it possible not only to change the configuration of the flame, but also to direct convective flue gas flows to the most efficient areas of the combustion chamber. The article considers various options for heat transfer (convective and radial) depending on various factors, taking into account the degree of probability of formation of pollutants (primarily NOx) in combustion products. The results of the numerical solution of the problem are presented. The analysis of the results on the optimal ratio of the shares of primary and secondary air flows for combustion was carried out. In conclusion, a comparative analysis of the options for burning fuel directly in the boiler and in the pre-combustion chamber is presented. The efficiency of direct combustion has been demonstrated.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"56 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139839318","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-66-77
A. B. Sukhotski
Providing consumers with heat of the required quality in the required quantity is quitea tall order. This is due to various laws of time variation in thermal loads of residential, public and industrial buildings, and the high inertia of district heating systems. Currently, new technical capabilities have appeared that make it possible to implement methods of quantitative and qualitative regulation of heat load in heat supply systems, which have a number of advantages over qualitative regulation. Based on the equations of heat transfer, thermal and hydraulic balance, the article shows the interactions between the parameters of various types of heat supply systems, viz. valve opening degree, throughput capacity, flow rate, and coolant temperature. The type of flow characteristics of the control valve, temperature characteristics of heat supply systems, temperature control characteristics, thermal and hydraulic characteristics of the regulated area are determined. The purpose of the article was to consider the influence of the maximum throughput capacity of the control valve on the thermal and hydraulic characteristics of dependent and independent water heating systems. As a result of the analysis of the thermal and hydraulic characteristics of heating systems, recommendations have been developed for selecting valve parameters to ensure high-quality temperature control. For independent heat supply systems with a heat exchanger, it is recommended to install a control valve with a concave (logarithmic, parabolic or other) characteristic. In the case of installing a valve with a linear characteristic, the heat exchanger throughput capacity need to be greater than the maximum throughput capacity of valve (the pressure loss of the medium flow in open valve is higher than the pressure loss in the heat exchanger). For dependent heat supply systems, it is recommended to install a control valve with a linear characteristic and a maximum throughput capacity five times less than the throughput capacity of the jumper.
{"title":"Determining of the Maximum Throughput of Control Valve in Heat Supply Systems","authors":"A. B. Sukhotski","doi":"10.21122/1029-7448-2024-67-1-66-77","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-66-77","url":null,"abstract":"Providing consumers with heat of the required quality in the required quantity is quitea tall order. This is due to various laws of time variation in thermal loads of residential, public and industrial buildings, and the high inertia of district heating systems. Currently, new technical capabilities have appeared that make it possible to implement methods of quantitative and qualitative regulation of heat load in heat supply systems, which have a number of advantages over qualitative regulation. Based on the equations of heat transfer, thermal and hydraulic balance, the article shows the interactions between the parameters of various types of heat supply systems, viz. valve opening degree, throughput capacity, flow rate, and coolant temperature. The type of flow characteristics of the control valve, temperature characteristics of heat supply systems, temperature control characteristics, thermal and hydraulic characteristics of the regulated area are determined. The purpose of the article was to consider the influence of the maximum throughput capacity of the control valve on the thermal and hydraulic characteristics of dependent and independent water heating systems. As a result of the analysis of the thermal and hydraulic characteristics of heating systems, recommendations have been developed for selecting valve parameters to ensure high-quality temperature control. For independent heat supply systems with a heat exchanger, it is recommended to install a control valve with a concave (logarithmic, parabolic or other) characteristic. In the case of installing a valve with a linear characteristic, the heat exchanger throughput capacity need to be greater than the maximum throughput capacity of valve (the pressure loss of the medium flow in open valve is higher than the pressure loss in the heat exchanger). For dependent heat supply systems, it is recommended to install a control valve with a linear characteristic and a maximum throughput capacity five times less than the throughput capacity of the jumper.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"171 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139841020","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-78-91
S. Saitov, N. Chichirova, A. Filimonova, N. B. Karnitsky
. Electrical power is the second most important commodity in electrical energy markets. For consumers, the charged amount of “generator” power is determined as the average value of hourly consumption amounts on working days during peak hours in the region. The cost of power in some regions can reach 40 % of the final tariff, so reducing the load during peak hours by 10 % can lead to a decrease in monthly consumer payments by 3 %. However, such a way of saving money is not available to the consumer since the commercial operator of the wholesale market of electricity and capacity publishes the peak hours of the regions after the 10th day of the next month, when this information is no longer relevant. Timely forecasting of peak hours will make it possible, on the one hand, to reduce consumer costs for payments for electric power, and on the other hand, to smooth out the daily schedule of electric load of the power system, thereby optimizing the operation of generating equipment of stations and networks of the system operator. The article presents a study of the effectiveness of machine learning methods in the context of forecasting the peak hour of a regional power system. The study concerns the period from November 2011 to October 2023, covers 76 regions of the Russian Federation, including subjects of price (1st and 2nd) and non-price zones and includes 10 machine-learning methods. The results of the study showed that statistically, the K-nearest neighbors clustering method turns out to be the most accurate, although not universal. Support Vector Classifier and Decision Tree Classifier have demonstrated high efficiency (in terms of accuracy and speed). The study also refuted the assumption that the closest data in terms of time series has the greatest value in predicting peak hours.
{"title":"Forecasting Peak Hours for Energy Consumption in Regional Power Systems","authors":"S. Saitov, N. Chichirova, A. Filimonova, N. B. Karnitsky","doi":"10.21122/1029-7448-2024-67-1-78-91","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-78-91","url":null,"abstract":". Electrical power is the second most important commodity in electrical energy markets. For consumers, the charged amount of “generator” power is determined as the average value of hourly consumption amounts on working days during peak hours in the region. The cost of power in some regions can reach 40 % of the final tariff, so reducing the load during peak hours by 10 % can lead to a decrease in monthly consumer payments by 3 %. However, such a way of saving money is not available to the consumer since the commercial operator of the wholesale market of electricity and capacity publishes the peak hours of the regions after the 10th day of the next month, when this information is no longer relevant. Timely forecasting of peak hours will make it possible, on the one hand, to reduce consumer costs for payments for electric power, and on the other hand, to smooth out the daily schedule of electric load of the power system, thereby optimizing the operation of generating equipment of stations and networks of the system operator. The article presents a study of the effectiveness of machine learning methods in the context of forecasting the peak hour of a regional power system. The study concerns the period from November 2011 to October 2023, covers 76 regions of the Russian Federation, including subjects of price (1st and 2nd) and non-price zones and includes 10 machine-learning methods. The results of the study showed that statistically, the K-nearest neighbors clustering method turns out to be the most accurate, although not universal. Support Vector Classifier and Decision Tree Classifier have demonstrated high efficiency (in terms of accuracy and speed). The study also refuted the assumption that the closest data in terms of time series has the greatest value in predicting peak hours.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"18 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139781634","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-5-15
Y. Rumiantsev, F. Romaniuk, V. Rumiantsev
In microprocessor automation and control systems, the amplitude (effective) values of the fundamental harmonic of the input signals are widely used as information parameters of the controlled quantities. They are most often determined by samples of one or a pair of orthogonal components of the signal, for the formation of which digital Fourier filters and their modifications are mainly used. At the rated frequency in the power system, these filters ensure reliable reception of the signal amplitude without additional error. If the frequency deviates from the rated one, the number of samples per signal period is not an integer and the discretization becomes asynchronous. As a result, a corresponding error appears in the amplitude of the signal, and its change becomes oscillating. With minor frequency fluctuations in the normal mode, the amplitude error is insignificant. However, in abnormal situations, the frequency can have significant variations. At the same time, in critical situations, failure of automation and control systems, as well as incorrect operation of their functional algorithms, cannot be excluded. Known methods for determining the amplitude of a signal with frequency fluctuations provide a solution to the existing problem, but they are characterized by a slow response. The proposed high-response method for determining the amplitude during frequency fluctuations is focused on using as initial information samples of instantaneous values of the cosine orthogonal component of the signal, which are formed using an appropriate digital Fourier filter. Based on these samples, the dynamic cosine and sine of the angle of one sample are calculated, the use of which in calculating the amplitude ensures its independence from frequency. Processing of the received amplitude with an amplifying element with a nonlinear coefficient makes it possible to achieve acceptable performance. The effectiveness of the proposed solution was evaluated by a computational experiment using a digital model implemented in the MATLAB-Simulink dynamic modeling environment. In this case, both sinusoidal input signals and complex ones, close to the real secondary signals of measuring transformers, were used as test actions. As a result of the research, it was found that the proposed method for determining the amplitude during frequency fluctuations has a performance at the level of a quarter of the period and provides effective elimination of frequency error both in load modes and in damage modes.
{"title":"A Fast-Response Method for Determining the Amplitude of a Signal in Microprocessor Automation and Control Systems with Frequency Fluctuations","authors":"Y. Rumiantsev, F. Romaniuk, V. Rumiantsev","doi":"10.21122/1029-7448-2024-67-1-5-15","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-5-15","url":null,"abstract":"In microprocessor automation and control systems, the amplitude (effective) values of the fundamental harmonic of the input signals are widely used as information parameters of the controlled quantities. They are most often determined by samples of one or a pair of orthogonal components of the signal, for the formation of which digital Fourier filters and their modifications are mainly used. At the rated frequency in the power system, these filters ensure reliable reception of the signal amplitude without additional error. If the frequency deviates from the rated one, the number of samples per signal period is not an integer and the discretization becomes asynchronous. As a result, a corresponding error appears in the amplitude of the signal, and its change becomes oscillating. With minor frequency fluctuations in the normal mode, the amplitude error is insignificant. However, in abnormal situations, the frequency can have significant variations. At the same time, in critical situations, failure of automation and control systems, as well as incorrect operation of their functional algorithms, cannot be excluded. Known methods for determining the amplitude of a signal with frequency fluctuations provide a solution to the existing problem, but they are characterized by a slow response. The proposed high-response method for determining the amplitude during frequency fluctuations is focused on using as initial information samples of instantaneous values of the cosine orthogonal component of the signal, which are formed using an appropriate digital Fourier filter. Based on these samples, the dynamic cosine and sine of the angle of one sample are calculated, the use of which in calculating the amplitude ensures its independence from frequency. Processing of the received amplitude with an amplifying element with a nonlinear coefficient makes it possible to achieve acceptable performance. The effectiveness of the proposed solution was evaluated by a computational experiment using a digital model implemented in the MATLAB-Simulink dynamic modeling environment. In this case, both sinusoidal input signals and complex ones, close to the real secondary signals of measuring transformers, were used as test actions. As a result of the research, it was found that the proposed method for determining the amplitude during frequency fluctuations has a performance at the level of a quarter of the period and provides effective elimination of frequency error both in load modes and in damage modes.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"214 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139839887","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-50-65
Yu. P. Yarmolchick, R. Schröger, H. Haberfelner, M. Pichler, D. Kostić, G. V. Moroz
To solve the problem of useful utilization (by combustion in heat generators) of liquid and gaseous industrial waste (that was defined in Part 1 of the present article), heat transfer processes in heat generating units were considered in Part 2. The main equipment for the effective solution of this process is a burner device and a combustion chamber with heat transfer to an external heat carrier, for example, a boiler furnace or a heat recovery boiler. The present article considers an example of calculating such a process for a distinctive mixture of waste from a chemical industry enterprise using modeling of possible schemes of a flame combustion system for a characteristic combination of various types of gaseous and liquid combustible products. For this purpose, the CFD (Computational Fluid Dynamics) computational hydrodynamics method was applied, which is determined to be the most effective one, in analyzing the behavior of media flows and combustion processes. CFD analysis makes it possible to predict hydrodynamic and thermal processes (especially in complex multicomponent systems) and optimize them to achieve the best results. The most important factor in high-quality combustion is the atomization process (fine atomization) of highly viscous liquids with high surface tension coefficients. The ultrasonic me-thod has been adopted as the most effective for such liquids. Besides, the quality of the distribution of flows of combustion mixtures and flue gases in the combustion chamber is considered. For doing this, it is necessary to arrange separate flows of axial and peripheral air, which make it possible not only to change the configuration of the flame, but also to direct convective flue gas flows to the most efficient areas of the combustion chamber. The article considers various options for heat transfer (convective and radial) depending on various factors, taking into account the degree of probability of formation of pollutants (primarily NOx) in combustion products. The results of the numerical solution of the problem are presented. The analysis of the results on the optimal ratio of the shares of primary and secondary air flows for combustion was carried out. In conclusion, a comparative analysis of the options for burning fuel directly in the boiler and in the pre-combustion chamber is presented. The efficiency of direct combustion has been demonstrated.
{"title":"Combined Combustion of Various Industrial Waste Flows in Boiler Furnaces. Part 3","authors":"Yu. P. Yarmolchick, R. Schröger, H. Haberfelner, M. Pichler, D. Kostić, G. V. Moroz","doi":"10.21122/1029-7448-2024-67-1-50-65","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-50-65","url":null,"abstract":"To solve the problem of useful utilization (by combustion in heat generators) of liquid and gaseous industrial waste (that was defined in Part 1 of the present article), heat transfer processes in heat generating units were considered in Part 2. The main equipment for the effective solution of this process is a burner device and a combustion chamber with heat transfer to an external heat carrier, for example, a boiler furnace or a heat recovery boiler. The present article considers an example of calculating such a process for a distinctive mixture of waste from a chemical industry enterprise using modeling of possible schemes of a flame combustion system for a characteristic combination of various types of gaseous and liquid combustible products. For this purpose, the CFD (Computational Fluid Dynamics) computational hydrodynamics method was applied, which is determined to be the most effective one, in analyzing the behavior of media flows and combustion processes. CFD analysis makes it possible to predict hydrodynamic and thermal processes (especially in complex multicomponent systems) and optimize them to achieve the best results. The most important factor in high-quality combustion is the atomization process (fine atomization) of highly viscous liquids with high surface tension coefficients. The ultrasonic me-thod has been adopted as the most effective for such liquids. Besides, the quality of the distribution of flows of combustion mixtures and flue gases in the combustion chamber is considered. For doing this, it is necessary to arrange separate flows of axial and peripheral air, which make it possible not only to change the configuration of the flame, but also to direct convective flue gas flows to the most efficient areas of the combustion chamber. The article considers various options for heat transfer (convective and radial) depending on various factors, taking into account the degree of probability of formation of pollutants (primarily NOx) in combustion products. The results of the numerical solution of the problem are presented. The analysis of the results on the optimal ratio of the shares of primary and secondary air flows for combustion was carried out. In conclusion, a comparative analysis of the options for burning fuel directly in the boiler and in the pre-combustion chamber is presented. The efficiency of direct combustion has been demonstrated.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"11 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139779661","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-66-77
A. B. Sukhotski
Providing consumers with heat of the required quality in the required quantity is quitea tall order. This is due to various laws of time variation in thermal loads of residential, public and industrial buildings, and the high inertia of district heating systems. Currently, new technical capabilities have appeared that make it possible to implement methods of quantitative and qualitative regulation of heat load in heat supply systems, which have a number of advantages over qualitative regulation. Based on the equations of heat transfer, thermal and hydraulic balance, the article shows the interactions between the parameters of various types of heat supply systems, viz. valve opening degree, throughput capacity, flow rate, and coolant temperature. The type of flow characteristics of the control valve, temperature characteristics of heat supply systems, temperature control characteristics, thermal and hydraulic characteristics of the regulated area are determined. The purpose of the article was to consider the influence of the maximum throughput capacity of the control valve on the thermal and hydraulic characteristics of dependent and independent water heating systems. As a result of the analysis of the thermal and hydraulic characteristics of heating systems, recommendations have been developed for selecting valve parameters to ensure high-quality temperature control. For independent heat supply systems with a heat exchanger, it is recommended to install a control valve with a concave (logarithmic, parabolic or other) characteristic. In the case of installing a valve with a linear characteristic, the heat exchanger throughput capacity need to be greater than the maximum throughput capacity of valve (the pressure loss of the medium flow in open valve is higher than the pressure loss in the heat exchanger). For dependent heat supply systems, it is recommended to install a control valve with a linear characteristic and a maximum throughput capacity five times less than the throughput capacity of the jumper.
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Pub Date : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-16-32
D. A. Sekatski, N. A. Papkova
. It is a very challenging task to correctly use weather data to calculate the active power loss due to corona in overhead power lines. One of the significant reasons for this was the problem of accuracy of determining weather conditions and the use of the forecast for calculating extended overhead lines. In the USSR (Union of Soviet Socialist Republics), based on field tests and experimental data, recommendations were developed for accounting for losses of electric energy due to corona and interference in overhead lines, the average values of which were given in the relevant instruction for the regulation and justification of the norm of electricity consumption for its transmission over electric networks. According to this regulatory document, the specific cost of active power due to corona in overhead lines, averaged by design, was determined depending on weather conditions, which were divided into four groups. In this paper, the effect of active power losses on corona is estimated using various factors on the example of high-voltage overhead lines in the main electrical networks of the Republic of Belarus of various rated voltages. Dependences of active power losses due to corona have been constructed and modeled, taking into account different climatic and weather conditions observed in the country. The determination of metrological parameters was based on the analysis of weather data and patterns of types of weather conditions. In order to improve the accuracy of calculating the specific losses of active power due to corona, all possible weather conditions were considered, as well as their combinations. Afterwards, the data on weather conditions were processed and their types were reduced to one of the four existing types of weather. A method for determining electric power losses due to corona in overhead lines based on the average relative air density and geometric parameters of the predominant section of overhead lines has been proposed and presented. It is shown that the usage of exclusively rated voltage can cause errors in determining both the specific and actual values of active power losses for corona.
{"title":"Calculation and Analysis of Specific Losses of Active Power in Overhead Power Lines due to Corona in View of Climatic Data","authors":"D. A. Sekatski, N. A. Papkova","doi":"10.21122/1029-7448-2024-67-1-16-32","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-16-32","url":null,"abstract":". It is a very challenging task to correctly use weather data to calculate the active power loss due to corona in overhead power lines. One of the significant reasons for this was the problem of accuracy of determining weather conditions and the use of the forecast for calculating extended overhead lines. In the USSR (Union of Soviet Socialist Republics), based on field tests and experimental data, recommendations were developed for accounting for losses of electric energy due to corona and interference in overhead lines, the average values of which were given in the relevant instruction for the regulation and justification of the norm of electricity consumption for its transmission over electric networks. According to this regulatory document, the specific cost of active power due to corona in overhead lines, averaged by design, was determined depending on weather conditions, which were divided into four groups. In this paper, the effect of active power losses on corona is estimated using various factors on the example of high-voltage overhead lines in the main electrical networks of the Republic of Belarus of various rated voltages. Dependences of active power losses due to corona have been constructed and modeled, taking into account different climatic and weather conditions observed in the country. The determination of metrological parameters was based on the analysis of weather data and patterns of types of weather conditions. In order to improve the accuracy of calculating the specific losses of active power due to corona, all possible weather conditions were considered, as well as their combinations. Afterwards, the data on weather conditions were processed and their types were reduced to one of the four existing types of weather. A method for determining electric power losses due to corona in overhead lines based on the average relative air density and geometric parameters of the predominant section of overhead lines has been proposed and presented. It is shown that the usage of exclusively rated voltage can cause errors in determining both the specific and actual values of active power losses for corona. ","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"129 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139841945","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 : 2024-02-13DOI: 10.21122/1029-7448-2024-67-1-33-49
G. Kulakov, N. V. Voyush
Steam temperature control significantly affects the efficiency, reliability and durability of steam boilers. In the article, special attention is paid to substantiating the relevance of a significant increase in the efficiency of steam boiler injection regulators operating in a wide range of load changes. It is indicated that one of the main directions of solving this problem is the use of optimal regulators with dynamic compensation and combined principles of regulation for deviation and perturbation at the same time. A combined automatic control system is proposed with full invariance with respect to the most dangerous measured internal disturbance and with partial invariance when working out an external disturbance with specified permissible deviations of the controlled parameter. At the same time, in order to improve the quality of regulation under the main influences, it is proposed to carry out optimization with the use of the transfer functions of the leading and main sections of the control object as well as to turn the internal contour of the two-circuit system into an amplifier with a single transmission coefficient when working out the corrective action. Also, it is proposed to form the structure of the corrective regulator on the basis of the principle of dynamic compensation for objects with a conditional delay along the channel of regulatory action, which makes it possible to ensure the specified quality of regulation when working out the control action surge. Thus, a significant increase in speed and accuracy is achieved when working out internal and external measured disturbances compared to a typical two-circuit system or an invariant automatic control system with an internal model, which makes it possible to recommend the proposed invariant cascade automatic control system for widespread implementation in the field of automation of thermal power processes.
{"title":"Structural and Parametric Optimization of Steam Boiler Injection Regulators","authors":"G. Kulakov, N. V. Voyush","doi":"10.21122/1029-7448-2024-67-1-33-49","DOIUrl":"https://doi.org/10.21122/1029-7448-2024-67-1-33-49","url":null,"abstract":"Steam temperature control significantly affects the efficiency, reliability and durability of steam boilers. In the article, special attention is paid to substantiating the relevance of a significant increase in the efficiency of steam boiler injection regulators operating in a wide range of load changes. It is indicated that one of the main directions of solving this problem is the use of optimal regulators with dynamic compensation and combined principles of regulation for deviation and perturbation at the same time. A combined automatic control system is proposed with full invariance with respect to the most dangerous measured internal disturbance and with partial invariance when working out an external disturbance with specified permissible deviations of the controlled parameter. At the same time, in order to improve the quality of regulation under the main influences, it is proposed to carry out optimization with the use of the transfer functions of the leading and main sections of the control object as well as to turn the internal contour of the two-circuit system into an amplifier with a single transmission coefficient when working out the corrective action. Also, it is proposed to form the structure of the corrective regulator on the basis of the principle of dynamic compensation for objects with a conditional delay along the channel of regulatory action, which makes it possible to ensure the specified quality of regulation when working out the control action surge. Thus, a significant increase in speed and accuracy is achieved when working out internal and external measured disturbances compared to a typical two-circuit system or an invariant automatic control system with an internal model, which makes it possible to recommend the proposed invariant cascade automatic control system for widespread implementation in the field of automation of thermal power processes.","PeriodicalId":502603,"journal":{"name":"ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations","volume":"7 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139779779","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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