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E-Journal N4(64)2024

"PROBLEMS of the REGIONAL ENERGETICS (https://doi.org/10.52254/1857-0070.2024.4-64)"

CONTENTS

1	Assessment of Power Transformer Technical State Using Explainable Artificial Intelligence Authors: Khalyasmaa A.I., Matrenin P.V., Eroshenko S.A. Ural Federal University, Ekaterinburg, Russian Federation
	Abstract: The functioning of deeply integrated technological systems in the power industry depends on the quality of power supply systems. Reliable power supply requires minimizing emergencies at power plants and substations. Reducing the accident rate is possible by switching to the mainte-nance and repair of high-voltage equipment based on its actual technical state. Machine learning methods make it possible to assess the actual technical state of various equipment types based on an aggregated analysis of many parameters, in contrast to methods based on comparing pa-rameters with boundary values without considering their mutual influence. Therefore, machine learning can be an effective tool for decision support systems for equipment diagnostics. The opacity of the models and the lack of interpretability of their recommendations significantly complicate industry implementation. The purpose of the study is to develop a method for in-creasing the interpretability of machine learning models for assessing the technical state of equipment. A power transformers’ oil dataset, decision tree ensembles and the Shapley additive explanations were used. The novelty of this study is the modification of the additive Shapley additive explanations, aimed at increasing the information content of the visualization of ma-chine learning model output interpretation. The most significant results are the substantiation of the applicability of explainable artificial intelligence for the assessment of the technical state of high-voltage equipment. In addition, for the first time in this problem, a Light gradient boosting method was applied. The proposed method allows for increasing the validity of the technical state assessment of high-voltage equipment using machine learning.
	Keywords: technical state, diagnostics, power transformers, explainable artificial intelligence, Shapley additive explanations. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.01
2	Application of Taguchi Method in Design of Surface Eddy Current Probes for Diagnostics of Power Equipment Authors: Halchenko V. Ya., Trembovetska R.V., Tychkov V.V. Cherkasy State Technological University, Cherkasy, Ukraine
	Abstract: The article’s aim is to create a method of reducing the influence on the surface eddy current probes output signal of a number of interfering parameters without their elimination, to ensure its stability, which is achieved as a result of computer search of design and operating values of probes Taguchi-parameters at the stage of their design. To achieve the goal the following tasks were carried out: software for calculating the output signal of surface probes, which is based on the electrodynamic model of the measurement process for the test object in the form of a con-ductive plate of infinite overall dimensions and finite thickness; using the Taguchi method, a special design of experiments with the use of orthogonal arrays is constructed, the fulfillment of which makes it possible to determine the influence of each parameter and their complex nonlin-ear interaction on the output signal of the probe; by integrating the Taguchi method with com-puter numerical simulation, the optimal controllable parameters of the probe were determined, minimizing the signal changes caused by noise factors. The most important research result is the method creation of providing the signals probes stability and reducing the influence of noise pa-rameters on them simultaneously without their elimination. The method effectiveness is demon-strated on the example of designing a thickness gauge, which allowed computer search for a set of its optimal parameters to maximize the signal-to-noise ratio, thereby reducing the signal varia-bility. The significance of the obtained results lies in the creation of theoretical and practical ap-proaches to the design of surface eddy current probes with new properties of interfering factors suppression, which provide the best conditions for reliable diagnostics of power equipment ob-jects.
	Keywords: Taguchi method, computer modeling, eddy current probe, noise suppression, design of experiment, orthogonal arrays, signal-to-noise ratio. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.02
3	Method of Diagnostics of Operation Modes of Individual Heat Supply Units, Allowing to Detect Pre-Emergency Situations at an Early Stage Authors: Dvortsevoy A.I., Borush O.V., Khoreva V.A., Yakovina I.N. Novosibirsk State Technical University Novosibirsk, Russian Federation
	Abstract: The use of machine learning methods to control heat supply systems is a pressing issue worldwide. The aim of the work is to develop methods for intellectualizing the operating modes of individual heat supply units (IHU) to improve their efficiency and reliability. To achieve this goal, the following tasks were solved: creating and debugging methods for diagnosing IH operating modes; using the cluster analysis method, in particular the K-means algorithm, to identify pre-emergency situations at an early stage; analyzing the relationship between outdoor air temperature data and the pressures of direct and return network water in IHU operating modes using Novosibirsk as an example. The most important results of the work include dividing the measured parameters into five clusters, each of which characterizes a certain IHS operating mode. This was confirmed by the "Elbow Method", which determined the optimal number, which made it possible to significantly improve the forecasting of emergency modes. Studies have shown that a sharp increase in outdoor temperature leads to an increase in the pressure of direct network water, which can cause accelerated wear of heating networks due to the peculiarities of weather-dependent automation regulation. Introducing additional parameters into the initial data, such as the service life of heating networks and weather conditions, can improve the accuracy of forecasts. The significance of the obtained results lies in the possibility of early detection of emergency and pre-emergency modes of IHU operation, which helps prevent accidents and reduce repair and maintenance costs.
	Keywords: heat supply unit, cluster analysis, intellectualization, heat supply, heating networks, weather-dependent regulation, emergence mode. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.03
4	Construction of the Automatic Control System of a Single-Screw Extruder Authors: 1Zablodskiy M., 2Klendiy P., 3Dudar O., 1Shvorov S. 1National University of Life and Environmental Sciences of Ukraine, Kyiv, Ukraine 2 Separated subdivision "Berezhany Agrotechnical Institute" National University of Life and Environmental Sciences of Ukraine, Berezhany, Ukraine 3Separated structural subdivision “Berezhany professional college of National University of Life and Environmental Sciences of Ukraine” Berezhany, Ukraine
	Abstract: The purpose of the work is to build the rational system for regulating technological parameters of the single-screw extruder using the frequency-regulated electric drive with limited use of sensors. This goal is achieved by the way of solving the following problems: development the method for controlling the technological parameters of the extruder with a controllable electric drive; development of a structural diagram of a model for estimating the speed of rotation a rotor of the engine without the use of velocity-type transducers; development of a functional diagram of the vector frequency-regulated electric drive with an observer that is built on the basis of a voltage equation corresponding to the main magnetic flux; development of a simulation model of the system of adjustable electric drive of the extruder and carrying out simulations with using the Matlab software package in the environment of Simulink. The most significant results of the researches are: the proposed algorithm for controlling the technological parameters (dynamic viscosity and pressure) by the way of calculating of the electrical power parameters of the adjustable electric drive of the extruder without the use velocity-type transducers; the functional diagram of the vector frequency-regulated electric drive of the single-screw extruder with the observer that was built on the basis of balance of the reactive capacity provides the necessary values of the technological parameters of the extruder. Changes in dynamic viscosity and pressure in the material, provides flexible adjustment without the use of speed sensors and rational use of electricity.
	Keywords: vector control, extrusion, dynamic viscosity, energy efficiency, simulation model. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.04
5	Use of Apple Pomace for Intensification of Biogas Production in the Anaerobic Digestion of Cattle Manure Authors: 1Polishchuk V., 1Shvorov S., 2Kucheruk P., 1Zablodskiy М., 1Galchynska Ju., 1Zubok T., 1Pasichnik N., 1Valiev T. 1 National University of Life and Environmental Sciences of Ukraine, Kyiv, Ukraine 2 Institute of Engineering Thermophysics of National Academy of Sciences of Ukraine, Kyiv, Ukraine
	Abstract: The goal of the work is to increase the yield of methane in biogas plants due to the joint methane fermentation of cattle manure with apple pomace. To achieve this goal, the following tasks were solved: the yield of biogas from cattle manure was determined with the addition of apple pomace to the substrate and fermentation in psychrophilic and mesophilic temperature conditions of the biogas plant. Based on the obtained experimental data of fermentation at temperatures of 22±1°C and 36±1°C of the fermenter, the biogas yield was assessed and the rational temperature regime for the operation of the biogas plant was determined. The studies were carried out on a laboratory biogas plant, consisting of a fermenter and a wet-type gasholder. A glass container with a total volume of 3 dm3 was used as a fermenter. The novelty of the chosen topic lies in the fact that the maximum methane output rate was determined under periodic loading of the fermenter, which for the psychrophilic temperature regime is 0.0033 m3/(kg DOM∙day), and in the mesophilic temperature regime mode 4 times more - 0.012 m3/(kg DOM∙day). The significance of the results lies in the fact that based on the results of the dynamics of methane output during periodic loading of the fermenter, it is possible to predict a constant methane output in industrial biogas plants that operate in a quasi-continuous mode, which will be equal to the maximum methane output during periodic loading of the fermenter
	Keywords: biogas, methane, apple pomace, cattle manure, fermenter. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.05
6	Experimental and Computational Studies of a Prototype Combustion Chamber for a Power Steam Boiler with a Vertical Precessing Vortex Authors: Boiko E.A., Semenov I.I., Lebedev K.V., Kulichkin A.P. Federal State Autonomous Educational Institution of Higher Education "Siberian Federal University" Krasnoyarsk, Russian Federation
	Abstract: . Increasing the efficiency of using fossil fuels at thermal power plants is an urgent task. This problem arises most acutely during the operation of pulverized coal power boilers using flare fuel combustion technologies. The purpose of this work is an experimental and computational study and justification of the technology of low-temperature combustion of coal in a combustion chamber with a vertical precessing vortex and the creation of a prototype combustion chamber for a power steam boiler. To achieve this goal, a study of the process of two-stage coal combustion was carried out, when the first stage of coal combustion is carried out in a pre-furnace with a fluidized bed, and the after-combustion of the products of incomplete combustion of coal is carried out with gas illumination in an after-combustion chamber with a vertical precessing vortex. The relationship between the main design parameters of the combustion chamber and the main operating characteristics of the diffusion vortex has been determined. The most important results are: development and experimental validation of the parameters of the combustion chamber with a vertical precessing vortex; determination of optimal operating modes of the furnace when burning coal and combined combustion of coal and gas; creation of a prototype furnace for a power steam boiler with natural circulation, operating on Kansk-Achinsk coal. The significance of the results obtained lies in the possibility of their use in the design of new or modernization of existing power boilers in order to increase the efficiency, reliability and environmental safety of operation.
	Keywords: experimental setup, analytical studies, coal, natural gas, combustion, furnace prototype, vertical precessing vortex, power boiler. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.06
7	Inertial Ferrofluidic Sensor for Vibration, Displacement and Impulse Measurement with a Linear Output Signal Authors: Koskov M.A., Somov S.A., Krylasova O.S., Ivanov A.S. "Institute of Continuous Media Mechanics of the Ural Branch of the Russian Academy of Sciences" is a branch of the Federal State Budgetary Scientific Institution Perm Federal Research Center of the Ural Branch of the Russian Academy of Sciences
	Abstract: The aim of the work is to develop the uniaxial ferrofluid sensor suitable for use either as an ac-celerometer for low-frequency vibrations or as a ballistic device or seismic sensor for shock loads. The goal is achieved by solving the following problems: development of a magnetic sus-pension system with a linear axial gradient of the magnetic field strength, calculation of the vis-cous friction force of the magnetic fluid filling the coaxial layer between the magnetic cylinder and the non-magnetic body wall, manufacturing of the sensor and its static and dynamic tests. The most significant result of the work is the experimental confirmation of the linearity of the electromechanical system of the sensor, corresponding to the model representations of a linear dissipative oscillating system with one degree of freedom. The significance of the obtained re-sults lies in the appearance of cheap and simple linear inertial sensors. The principle of opera-tion of the sensor is based on the registration of the motion of an inert mass deviating from the equilibrium position under the action of an external force to be measured. The inert mass, con-sisting of ring permanent magnets, levitates in a coaxial layer of magneto-fluid lubricant. The sensor, depending on its parameters, can measure either quasi-static force, or force impulse, or coordinate displacement, which is in demand in monitoring systems for critical structures and buildings, as well as in navigation systems for vehicles operating under conditions of small, slowly changing accelerations (microgravity).
	Keywords: magnetic fluid, inertial sensor, permanent magnet, viscous friction. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.07
8	Study of Steam Turbine Unit Operation Using Natural Gas Combustion in Pure Oxygen to Ensure Decarbonisation through Gas Path Modernization (using the Example of a TGM-94 (EP-500/140) steam boiler) Authors: 1Shaposhnikov V.V., 2Butuzov V.A., 1Kocharyan E.V., 1Batko D.N., 1Shelest N.A. 1Kuban State Technological University, Krasnodar, Russia 2Kuban State Agrarian University named after I.T. Trubilin, Krasnodar, Russian Federation
	Abstract: The research is aimed at substantiating the technical use of natural gas combustion in an environment with a high oxygen content and, in the long-run objective - in pure oxygen in a steam turbine power unit. To achieve this aim, the following problems were solved: the development of a mathematical model of a steam turbine power unit for operation when burning natural gas in pure oxygen, a numerical study of the power unit operation when replacing air with oxygen from 0 to 100%, and an assessment of the efficiency of the equipment in these modes. The most important result is an increase in the efficiency of the steam turbine power unit when switching to burning natural gas in an environment with a high oxygen content. The significance of the results obtained is to ensure the efficiency of CO2 capture from flue gases without a complete reconstruction of the facility. The object of the study was the Krasnodar Thermal Power Plant. In the study, the previously verified mathematical model of the power unit was modified. The model was created using the Boiler Designer software product. The mathematical model was modified by zeroing air leaks into the boiler gas path, replacing the regenerative air heater with a tubular one, and bypassing the air heater along the flue gases when operating on an oxygen-air mixture. The maximum increase in the boiler unit efficiency is 0.6% and is in the range of air substitution with oxygen from 40 to 60%.
	Keywords: boiler unit, thermal power plant, steam turbine unit, oxygen combustion, carbon dioxide. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.08
9	Incremental Efficiency of Electricity Generation Based on Thermal Consumption at CHPPs and its Importance in Reducing Carbon Emissions Authors: Suvorov D.M., Tatarinova N.V. Vyatka State University Kirov, Russian Federation
	Abstract: The aim of the study is to develop a methodological approach to assessing the incremental effi-ciency of electricity generation at CHPPs (specific heat consumption for changing electric power of turbine) in operating modes, taking into account both energy and environmental indicators. To achieve this goal, the following tasks were solved: the methodology, based on mathematical models of cogeneration steam turbines, both integral and differential indicators of heat rate per unit of electricity generation increment, was justified; a comprehensive generalization of the cal-culation data on the turbine T-50-12.8 type was performed; a quantitative assessment of the in-tegral electricity generation and greenhouse gas emissions parameters was made at various loads and its comparison with the corresponding indicators in condensation mode. The most signifi-cant results are the following: generalized dependences of the integral specific heat consumption per unit of increase in electricity generation and carbon footprint were calculated for a wide range of changes in operating conditions; boundary conditions were established under which obtaining these parameters by opening the sliding grid of low-pressure section turns out to be energetically and ecologically feasible; it was determined that when increasing the capacity without bypassing the delivery water, the carbon footprint increment with an increase in the ca-pacity of cogeneration turbines by opening the sliding grid will be less than for condensing tur-bines. The significance of the results obtained lies in their applicability for solving problems of ensuring maximum efficiency during involving cogeneration turbines in regulating electric load schedules in different boundary conditions.
	Keywords: incremental efficiency of electricity generation, heat rate, carbon emissions, sliding grid of low-pressure section, cogeneration, operating modes of CHPP. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.09
10	Analysis of Syngas Combustion Process in Piston Engines Authors: 1Mytrofanov O., 1Proskurin A., 2Kong W. 1Admiral Makarov National University of Shipbuilding Mykolaiv, Ukraine 2 Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
	Abstract: The article examines the features of the combustion process of hydrogen-containing gas (syn-gas) in the working cylinder of a spark-ignition internal combustion engine. The main objective of the study is to evaluate the heat release parameters of syngas. To achieve this goal, an exper-imental investigation was conducted to assess the nature of syngas combustion and establish its regularity. The most significant result is the derivation of dependencies for determining the cur-rent value of the combustion characteristic index m and the combustion duration φz in Professor I.I.Vibe's heat release model for spark-ignition engines operating on syngas, with an air excess ratio α ranging from 1.0 to 2.2 and hydrogen content in the fuel composition varying between 30% and 100% by volume. The significance of the obtained results lies in the establishment of the variability of the combustion index m (ranging from 1.6 to 5.5) in Professor I.I.Vibe's semi-empirical heat release model, which more closely corresponds to the actual heat release law ob-served in experimental studies. The proposed dependencies for determining m and φz allow for accounting the specific features of the syngas combustion process in spark-ignition engines, thereby significantly improving the accuracy of determining the indicated pressure in the work-ing cylinder (the relative root-mean-square error does not exceed 4.5%), which, in turn, enhances the accuracy of assessing the engine's energy and economic parameters. The results of this study can be applied in the design and construction of new spark-ignition engines running on alternative fuel.
	Keywords: alternative fuel, syngas, combustion heat release characteristics, working process, combustion index, combustion duration. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.10
11	Damage to Steam Turbine Rotors Due to Asynchronous Connections of Electric Generators to the Unified Power System Authors: Chernousenko O.Yu.1, Marysiuk B.A.2 1National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukraine 2 Odesа Polytechnic National University, Odesa, Ukraine
	Abstract: The article aims to contribute to the ongoing study of damage to steam turbine rotors resulting from asynchronous connection of electric generators to the unified power system. At the present time, the assessment of the residual life of steam turbine equipment is based on the study of the degradation of the mechanical properties of steels and the analysis of the thermal stress state. The aim of this work was to determine the impact of such vibrations on the mechanical proper-ties of rotors and their damage. This goal was achieved by solving the following tasks: develop-ing a 3D model of the K-1000-60/3000 LMZ turbine unit shaft based on design documentation; calculating the stress-strain state of the shaft resulting from asynchronous connections using fi-nite element analysis; and evaluating the level of metal damage in the rotors due to torsional vi-brations. The developed mathematical model used a classical approach, replacing the working blades and bandage fastenings with concentrated masses and moments of inertia. The most im-portant results are the calculated rotor damages that occur due to asynchronous connection of the turbogenerator to the unified power system with a synchronization angle of 30°. The greatest damage to the rotor metal was found in the shaft section between the steam turbine and the elec-tric generator. The significance of the results obtained is that the use of this data will improve methods for assessing the remaining life of turbogenerators. This, in turn, will improve the relia-bility and safety of power plant operations.
	Keywords: steam turbine, rotor, asynchronous connection, torsional vibrations, stress-strain state, damage. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.11
12	Proposals for the Multiparametric Design Application in Electrical Mechanical Engineering Authors: Mechanical Engineering 1Shevchenko Valentina V., 1Minko Alexander N., 2Stoychev Vladimir T. 1National Technical University "Kharkiv Polytechnic Institute", Kharkiv, Ukraine 2 Company «Dinamo Sliven AD», Sliven, Bulgaria
	Abstract: The aim of the work is to obtain practical results for the electrical machines multiparametric de-sign application, to conduct a comparative analysis of the parametric and multiparametric design results of a turbogenerator and its elements when the load changes; to confirm the prospects the multiparametric design application. Currently, it is possible to use mathematical models when designing, and use parametric synthesis to optimize one specific parameter, which in certain cas-es turns out to be sufficient. The peculiarity of electric machines calculation and design is the necessity of simultaneous checking of all interrelated parameters (mechanical, electromagnetic, thermal) with any changes. The structure design with simultaneous control of several variables cannot be performed using one stage of parametric design; additional calculations are necessary. In this case, multi-parameter design is necessary, but it requires longer preparation for design work and higher qualifications of personnel. Therefore, it is necessary to understand in which cases it is advisable to switch from parametric to multiparametric design. The work goal set is achieved by comparing the results of a turbogenerator, stator core and busbar designing using parametric and multiparametric design. The most important is to obtain the results of comparison of a complex electromechanical system parametric and multiparametric design (turbogenerator, its individual unit and element), including when the parameters of various physical processes change, performing a comparison of the obtained results, confirming the feasibility of carrying out multiparametric design. The significance of the obtained results is that practical examples of the multiparameter modeling use are shown. Using multiparametric design, not only a busbar refined form with increased repair and operational reliability was obtained, but the proposed so-lution economic advantages were also indicated.
	Keywords: turbogenerator, stator core, busbar, parametric and multiparametric design and modeling, elec-tromagnetic, thermal and mechanical factors. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.12
13	Control of Carbon Dioxide Bivalent Heat Pump on Heating of Buildings. Part II Authors: 1Sit M.L., 1Juravleov A.A., 2Frid S.E., 1Timchenko D.V., 3Denysova A.E. 1Institute of Power Engineering of the Technical University of Moldova Chisinau, Republic of Moldova 2Joint Institute for High Temperatures of the Russian Academy of Sciences, Moscow, Russian Federation 3Odessа Polytechnic National University, Odessa, Ukraine
	Abstract: The control system of a bivalent heat pump (BHP), using as low potential heat (LPH) sources both the heat of the return water of the network and the heat of the outside air, is considered. The aim of the work is to determine the parameters of the thermodynamic cycle of the heat pump, which would ensure the operation of the heat pump at variable temperatures and flow rates of the refrigerant in the load. The set goal is achieved by solving the following tasks: analy-sis of the methods of synthesis of systems at variable load, analysis of the operation of the sys-tem at random disturbances, development of the heat pump automatic control system (ACS). The main result of the work is: the scheme of the heat pump, which can work with variable pressures of the evaporator and the gas cooler, as well as the technical solution, in which the en-thalpy difference at the evaporator remains constant regardless of the outside air temperatures Significance of the obtained results consists in creation of the BTN scheme, which allows to provide both qualitative and qualitative-quantitative laws of regulation of thermal regime of a building at increase of SOR of a heat pump, thanks to rational choice of a temperature schedule of regulation. Local storage using electrochemical accumulators at the required capacity would be very expensive and would make the entire installation unprofitable. The only reasonable so-lution is interaction with the grid, which requires, in addition to the technical means of interfac-ing, the presence of appropriate regulations governing the transfer of electricity generated by the local facility to the grid, especially if the generation will be carried out throughout the year.
	Keywords: bivalent heat pump scheme, automatic control, random disturbances, reliability, district heating, carbon dioxide. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.13
14	Decision Support System for Diagnosing Underwater Electrical Cables Authors: Tymochko O.1, Tymoshchuk О.2, Timochko O.3, Boiko S.2, Mazhara I.4, Hannoshina, I.,2 Shapran Yu.2 ¹Flight Academy of the National Aviation University, Kropyvnytskyi, Ukraine 2State University of Infrastructure and Technologies, Kyiv, Ukraine ³firm AFC autofleet control, Hamburg, Germany 4Ivan Kozhedub Kharkiv National Air Force University, Kharkiv, Ukraine
	Abstract: The object of this study is the process of generating an appropriate response by an intelligent agent when detecting and tracking an underwater electrical cable using a decision support system. The goal of the work is to develop the architecture of a decision support system for diagnosing underwater electrical cables and the main algorithms for its operation. To achieve the research goal, intelligent agents with a complex IPK architecture, which includes information, preferences (rules), and knowledge, were used. The combination of the structure of intelligent agents and the advantages of hierarchical knowledge bases allowed for the natural language representation of knowledge. The functional core of the system consists of four main agents, one of which facilitates the interaction between the user and the surrounding environment. To address the uncertainty in the cable's position on the seabed, the capabilities of fuzzy sets, describing its feature space with membership functions, were employed. The most significant results involve planning for the detection and tracking of underwater electrical cables, taking into account past decision-making experiences in similar cases and adapting them to the current situation through case-based reasoning. The importance of the obtained results lies in providing the decision-maker with a possible option for deploying an underwater vehicle based on accepted logic and rules for detecting underwater electrical cables. Further research is focused on implementing automatic target selection for intervention and developing a method for automatic modification of reasoning methods, preference rule bases, and operational knowledge.
	Keywords: electrical cable, diagnostics, autonomous underwater vehicle, navigation, motion control, fuzzy sets, intelligent agent, decision support system. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.14
15	Efficient Wireless Power Transmission System Authors: Panteleev V.I., Maleev A.V., Petukhov R.A., Sizganova E.Yu. Siberian Federal University Krasnoyarsk, Russian Federation
	Abstract: The work focuses on wireless power transfer for electric vehicle charging stations. The aim of the study is to analyse the processes in the system of wireless magnetic resonance transmission of electrical energy using magnetic fields and to develop approaches to improve the efficiency of such systems. The set objectives were achieved by solving the following problems: the opera-tion of the wireless power transmission system with a resonance-tuned transmission coil, the de-termination of the optimal energy parameters of wireless power transmission on the example of a magnetically coupled system with a series-sequential resonant circuit. The main results of the study are as follows: it is shown that the necessary condition for obtaining the maximum power in the receiver is not only the tuning to the resistance of the receiving coil, but also the inclusion of the receiving circuit to a certain active load resistance, depending on the coupling coefficient between the transmitting and receiving coils, and analytical expressions are obtained, by means of which it is possible to calculate the load resistance at which the considered power transmis-sion system has the maximum efficiency; it is proved that the transmission efficiency of the se-ries-sequential resonant circuit is maximum in the single resonance mode and depends on the coupling coefficient. Significance of the obtained results: It is proved that magnetic resonance transmission of electric energy in the case of series-sequential scheme of wireless power trans-mission is more effective in comparison with series-parallel, at frequencies not exceeding 100 kHz, which has a positive effect on the operation of charging stations for electric vehicles in an urban industrial environment and, as a result, on solving the problem of compliance of such sys-tems with electromagnetic compatibility requirements.
	Keywords: mutual inductance, electromagnetic coupling coefficient, resonant frequency, magnetically coupled energy transfer circuit, transmission efficiency, quality factor. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.15
16	Studies of Reliability of Power Supply of the Enterprise from the Electric Power System and Autonomous Loaded Generators Based on Markov Processes Authors: Basmanov V.G., Kholmanskikh V.M., Suntsov K.A. Vyatka State University Kirov, Russian Federation
	Abstract: The purpose of this work is to substantiate the use of probabilistic components of the availabil-ity factor of the power supply system (PSS) of the enterprise consisting of a electric power sys-tem and autonomous loaded generators, to calculate overpayments for electricity. To achieve this purpose, operation of the PSS during the last 5 years was studied. The PSS was considered as a restored system which has spinning reserve. The process of the PSS functioning was repre-sented by a simple non-branching graph with one repair team and described by systems of dif-ferential and algebraic equations. The solution of the latter allowed calculating the probability components of the PSS availability factor. The operating time of the PSS in a calendar year was calculated with a different number of serviceable generators. The method for calculating over-payment for electricity was proposed. The most significant result is the justification of the use of probability components of the PSS availability factor for assessing overpayment for electricity. The significance of the obtained results lies in the fact that the proposed formula for overpay-ment for electricity allows to estimate overpayment, identify main causes and recommend measures to reduce it. The reliability of the results is confirmed by the example of calculating overpayment for electricity for a real enterprise. The newly obtained indicators of generator reli-ability can be used in the analysis of overpayment by other enterprises, which have similar gen-erators.
	Keywords: PSS, autonomous generators, state graph, availability factor, overpayment for electricity, failure and recovery models. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.16
17	Intensification of Hydrate Formation by Microbubbles Authors: Kutnyi B.A, Krot O.P., Chernetska I.V. National University "Yuri Kondratyuk Poltava Polytechnic" Poltava, Ukraine
	Abstract: Іndustrial synthesis of gas hydrates is a promising area for storage, transportation and utilisation of natural gas. The aim of this work is to evaluate the factors that affect the efficiency of gas hydrate synthesis, in particular, the influence of gas microbubble generation. To achieve the goal, the following tasks were solved: the experimental unit was developed and assembled; the experimental research methodology was proposed; experimental data were obtained and their statistical analysis was performed; a mathematical model of hydrodynamic and heat and mass-exchange processes in the nozzle was developed; оn the basis of the mathematical model, a calculation program was created which allows analyzing the nozzle operation in different thermobaric conditions under different hydrodynamic regimes. The most important are the results of experiments, which allowed us to determine the factors that have the greatest influence on the intensification of propane hydrate synthesis: the presence of gas microbubbles, liquid temperature, gas temperature, gas pressure in the reactor and others. The influence of individual factors and the presence of gas mixture microbubbles on the intensity of mass transfer processes of hydrate formation in the reactor was determined. The influence of nozzle design features on the efficiency of hydrate formation was analyzed. The significance of the obtained results is to expand knowledge about the influence of various factors on the intensification of gas hydrate synthesis. The research results can be used for designing industrial plants for gas hydrate synthesis.
	Keywords: gas hydrates, experimental setup, microbubbles, heat and mass transfer processes, mathematical model, nozzle. DOI: https://doi.org/10.52254/1857-0070.2024.4-64.17