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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.

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.

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.

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.

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.

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.

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).

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.

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, enhanc-es 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.

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.

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.

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.

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.

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.

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.

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.

The purpose of the work is a theoretical and experimental study of the effectiveness of combined shielding, including active and passive shielding using a continuous screen, of the magnetic field generated by single-circuit power lines with a triangular arrangement of wires inside multi-storey buildings. To achieve this goal, the structure of the combined screen has been determined, which consists of a double-circuit active and a U-shaped solid passive part, and is characterized by increased efficiency in reducing the level of the industrial frequency magnetic field. Designing a combined screen comes down to solving a minimax vector optimization problem, in which the vector objective function is calculated based on solutions to Maxwell's equations in a quasi-stationary approximation using the COMSOL Multiphysics software package. The most important results are the values of the coordinates of the spatial location of two compensation windings, the magnitude of currents and their phases in these windings of the active shielding system, as well as the parameters of the U-shaped continuous passive screen, which made it possible to increase the efficiency of shielding the magnetic field generated by single-circuit lines, calculated during the design of the combined screen. power transmission with a triangular arrangement of wires inside multi-storey buildings.The significance of the results obtained is that practical recommendations are given for the reasonable choice of the spatial arrangement of two shielding windings of a robust active shielding system and the parameters of a U-shaped continuous passive shield of combined shielding of the magnetic field generated by single-circuit overhead power lines inside multi-storey buildings.

The work is devoted to the problem of water purification during the flowering of phytoplankton, as well as during salvo pollution by industrial effluents. Anthropogenic load significantly reduc-es the efficiency of purification according to the current technology, therefore, additional post-treatment methods must be used to obtain purified water of the required quality. The purpose of this article is to substantiate the choice of a sorbent within the framework of the considered wa-ter treatment technology, as well as to determine the optimal effective dosage of its dosing. This goal is achieved by implementing the following tasks: analysis of powdered sorption materials used in water treatment technology, selection of an effective dose and entry point of the selected sorption material based on experimental studies, analysis of the results obtained; and develop-ment of technical solutions for the organization of a hybrid purification plant. The most im-portant results are: determination of the optimal dose of coal pulp and the frequency of dosing to maintain the required quality of purified water; and determination of key water quality indica-tors affected by treatment with activated carbon. The achievement of these results made it pos-sible to determine the main technological features of the water purification method and deter-mine the possibility of combining it with other purification technologies. The significance of the results obtained lies in the fact that new technical solutions have been proposed to improve the efficiency of water treatment facilities during a period of drastic changes in water quality at a water source.

. The widespread introduction of information technologies into all spheres of society, the crea-tion of a significant amount of confidential and critical data in digital form leads to an increase in the priority of information security tasks everywhere, including in the energy sector, which relates to the critical infrastructure of any state. The purpose of the work is to develop the men-tioned approach to ensure the possibility of increasing the efficiency of information security methods based on it. The goal was achieved through a detailed study of disturbances in the val-ues of formal parameters that uniquely determine the matrix that is assigned to the information security system under conditions of active attacks (disturbances) on the system. Singular num-bers and singular vectors of the matrix are considered as such parameters. The most important result of the work is the substantiation of the existence and establishment of interconnected re-gions of stabilization of disturbances of singular numbers and singular vectors of the system ma-trix, while the region of stabilization of singular numbers corresponds to the region of monoto-nous decrease in their disturbances with increasing numbers, while the stabilization of singular vectors corresponds to the region in which their disturbances are comparable with 90 degrees. It is shown that the stabilization process is determined by the mathematical properties of the pa-rameters under consideration. The significance of the obtained result lies in the possibility of using it to improve various information security systems that were built or studied using a gen-eral approach to analyzing their state, both theoretically and practically. The work provides ex-amples of such use.

The purpose of the article is to develop the principle of forming integrated energy supply sys-tems that consider the relationship between the production, transmission and consumption of thermal and electrical energy, as well as to develop a methodology for selecting the composition and structure of generating equipment to ensure the affordability and uninterrupted supply of energy. To achieve this purpose, the following tasks were accomplished: the energy supply sys-tems of existing special economic zones were studied, and their shortcomings were identified; the creation of integrated energy supply systems for territories based on cogeneration technolo-gies was proposed; a methodology for selecting the composition and structure of equipment for mini-CHPP (combined heat power plant) integrated energy systems was developed. The most important result is a comprehensive methodology for selecting the composition and structure of mini-CHPP equipment in an integrated energy supply system, ensuring maximum fuel efficiency for energy production and energy efficiency for the energy supply system. Performing calcula-tions based on the developed methodology using the example of the advanced development area «SmartCity-Novosibirsk», we were able to propose the creation of an integrated energy supply system for residents. The significance of these results lies in their potential to improve the effi-ciency of decision-making processes in the field of energy infrastructure development by con-sidering interconnections between heat and power supply processes and the methodology of se-lecting mini-CHPP equipment for integrated energy systems.

The need of switch to burn non-design fuel arises during the thermal power plants long-term operation. The choice of replacing coal is quite complicated and currently being solved by various non-design fuels experimental combustion on a specific power boiler. The aim of the work is to develop criteria assessing non-design coal burning possibility in a specific furnace before experimental combustion. The stated goal is achieved with the help of numerical combustion modeling regarding various coals at the pre-critical parameters boiler furnace with an average composition ranking by the lower calorific value. 2 burning ratios have been proposed based on foreign experience: the fuel ratio and the degree of fuel burnout. The first is the ratio of the fuel carbon to volatile substances contents, which in this work are taken as an analytical mass. The second is calculated with the proposed formula, which, instead of the combustible content in fly ash, use mechanical underburning widely included in the technical calculations. Combustion zones with the degree of the acceptable fuel burnout according to the standards and with its excess are distinguished. The limit of possible coal combustion according to the fuel coefficient is found as well. It is shown that this furnace is quite universal for burning a wide range of coals, although it was originally designed for burning brown coal. It is not recommended to burn only lean and low-caking bituminous coals, anthracites and brown coals with calorific value less than 11.5 MJ/kg or humidity more than 40%. The obtained results are significant for the preliminary assessment of non-design fuel combustion and narrowing the range of fuels under consideration. Other the boiler conversion consequences for non-design fuel should be taken into account for the final decision, and above all, the probability of the heating surfaces slagging.

The aim of this work is to establish energy-efficient fruit dehydration regimes in a modified atmosphere. To achieve the goal, an experimental electrical installation was developed, which applies in the technological process the CO2 modified atmosphere dehydration method. Carbon dioxide was used as a drying agent because it is harmless for food and for the human body, including even children and is often used in food industry. The researches were focused on the example of the local origin fruits dehydration, but in particular, peaches were selected as the main object of the research, because they are extremely sensitive to both storage and processing, and the current technologies applied in their case have low efficiency due to adverse reactions that cause processing defects. The essential problems in the dehydration of peaches are the oxidation of the superficial layer and the browning, which considerably reduce the quality of the finished products and also require an increased energy intake, and because of the mentioned shortcomings, these fruits are mainly used during the season, being mainly consumed fresh, nevertheless the dried fruits are of interest and are sought after by consumers the year-around. The main results obtained with the application of the elaborated installation are: increasing in the energy efficiency and the quality of the finished products. The significance of these results lies in the solution of the essential characteristic problems of the fruit dehydration process, which are currently faced by specialized companies in the respective field.

The aim of this work is the utilization of the secondary steam energy through its thermal transformation in electrodynamic dehydrators developed by the authors. To achieve this goal, the use of heat pumps is proposed. A hypothesis is formulated that the use of electromagnetic energy sources in the process of removing moisture from food solutions, followed by the transformation of secondary steam energy, will allow for the formation of reverse energy flows. A method for calculating energy efficiency in the presence of direct and reverse flows is presented. Multistage dehydrators, where electrodynamic systems are used at the final stage and heat pumps at the previous stages, are analyzed. It is shown that the formation of reverse flows significantly increases the overall energy efficiency. The use of an electrodynamic apparatus at the final stage solves the problems of obtaining a highly concentrated quality solution. The application of heat pumps at the remaining stages allows for the efficient use of secondary steam energy. The most significant result is the matching schemes of heat pumps with the dehydrator and the environment. The importance of the work lies in the substantiation and confirmation of the high energy efficiency of organizing reverse energy flows, and the proposed installation with combined systems — electrodynamic and heat pump. By calculation, the modes have been established in which the overall efficiency for two-stage apparatuses with heat pumps can be increased from 0.4 to 0.6, and for four-stage dehydrators from 0.4 to 0.8.

The purpose of the article is to substantiate the possibility of selecting objects in the image generated by the technical vision system of an unmanned aerial vehicle by using structural and geometric features. This goal is achieved based on the analysis of the distribution of fractal dimension, which characterizes the structural properties of images, taking into account the object content, and the size of the area of the selection object. The solution to the first problem is based on the formation of histograms of fractal dimension depending on the number of objects in the image and identifying the features by which the object is selected. The solution to the second problem is based on developing an approach to reducing the object content of images by making it noisy. The noise parameters at which signs of object selection appear in the histograms of the distribution of fractal dimensions are determined. The range of fractal dimension defined. The solution to the third problem is based on specifying the selection object by its area. The most significant result is the identified values of fractal dimension ranges depending on the object content of the image, as well as experimentally established noise parameters to identify the necessary features in histograms of fractal dimensions. The significance of the work lies in solving the problem of selecting a reference object on images of heterogeneous object composition. This made it possible to reduce significantly the computational complexity of selecting objects in images.

The aim of the study is to review the use of gas products of natural and synthetic origin and their future application prospects. To achieve this goal, a number of high-tech technologies were pre-sented and analysed. The phase equilibrium parameters of inert and fluorine-containing gases were shown, as well as the temperature ranges in which certain refrigerants can be applied. Ex-amples of cooler schemes for providing rectification processes at 28 and 210 K were given. The processes of refrigeration cycles in T-s diagrams of neon and R116 (hexafluoroethane) were shown. Schemes of helium systems for heat removal at the level of 5…28 K were considered. The areas of application of Xe, Kr, Ne, and He in modern technologies, particularly in laser technology, space exploration, lamp industry, and medicine, were highlighted. The most signifi-cant result of the work is the determination of the important role of isotopic components of inert gases for the future of energy, functional diagnostics, metrology, and other fields. In semicon-ductor manufacturing, many inert gases are used as protective environments and working media in ion-plasma and ion-beam etching in vacuum chambers. In plasma chemical surface treatment, substances containing one or more halogen atoms act as active gases. The significance of the results achieved is evident in that, in the context of a global shortage of technical gases, the de-velopment of resource-saving technologies is becoming relevant. Among these, gas product re-cycling, where gas concentrates were obtained from used mixtures, enriched, and subjected to deep purification for the secondary use of target products, is the most promising.

Increasingly, low-capacity electricity generating installations using renewable energy sources are becoming widespread. They bring imbalance to the energy system. Frequency control is carried out using powerful steam turbines. To ensure reliable and efficient operation of powerful steam turbines, it is important to understand the processes occurring in the last stages of the low-pressure cylinder. At present, there is no approach to determining the idle mode (the moment of transition from the generation of mechanical power to its consumption) for large fanning stages. The purpose of the work is to develop an approach to estimating the relative volumetric steam flow rate of steam for large fanning stages, which characterizes the idle mode. This goal is achieved by developing a dependence to determine the idle mode for large fanning stages at nominal operating mode in a compressible medium using the results of an experimental study of model stages for high power turbines. The most important result is the satisfactory agreement between the values of volume flow rate obtained during the calculation, using the proposed method, with experimentally studies for the T-250/300-240 turbine last stage. The calculation error is about 3%. The significance of the results obtained is that the proposed approach allows determining the idle mode of the low-pressure cylinder stages of steam turbines quickly and ac-curately during operation and design, which makes it possible to increase the efficiency and reli-ability of power units.

The object of the study is to enhance operational efficiency and reduce fuel consumption of autonomous underwater vehicles during the monitoring of underwater electrical and optical cables based on FCA under conditions of uncertainty. To achieve the goal of the research fuzzy cellular automata are used, combining the advantages inherent in traditional cellular automata and provided by the capabilities of fuzzy sets and fuzzy logic. The cable location uncertainty is caused by possible earthquakes, turbulent currents, random impacts of anchors or fishing gear, cable fouling by marine vegetation and terrorist attacks. The developed approach allows to synthesise a Pareto-optimal vehicle route along the estimated coordinates of the object of study, providing minimum fuel consumption for minimum cable inspection time and satisfying the given system of constraints. Formal models are based on the use of fuzzy cellular automata, which are used to describe the three-dimensional model of the operating environment, zones and objects that hinder or limit the movement, and the behaviour of the underwater vehicle. The most significant results are the formal description of the problem solution space, and the method of modelling the route of an autonomous underwater vehicle in space to improve the efficiency and quality of the solution of the problem of monitoring the state of the object of interest. The significance of the results obtained is the possibility of solving a complex multi-criteria optimisation problem of finding the route of an autonomous underwater vehicle to monitor the cable system in three-dimensional space.

The paper deals with research of the booster transformer (regulation transformer), which can be attributed to “Sen” family, which has an extended range and higher control accuracy. The main aim of the paper is to study both operational and energy characteristics of the transformer device that implements output voltage longitudinal-transverse regulation principle relative to the input based on power electronics. The most significant research results can be considered new developed circuit design and method for windings sectioning, including their regulating control strategy. The obtained computational experiments results based on developed structural simulation models of the booster transformer demonstrated effectiveness of the proposed device technical solution and its control strategy in terms of significant expansion of the output voltage range both in magnitude and in phase. It is shown that the proposed technical solution provides greater possibilities for phase voltage regulation (relative to the UPFC and “Sen” transformer) with the same restrictions on the longitudinal and transverse components of the boost voltage. Vector diagrams of the studded device were constructed and expressions characterizing its operating parameters were obtained. The characteristics of the device parameters variation in both idle and load mode were obtained and analyzed. The significance of the obtained results consisting in fact, that the proposed technical solution is capable to provide the same control actions in the form of an adjustable additional voltage as FACTS controllers such as UPFC and “Sen” - transformer, but on a simpler basis that is more accessible to practical implementation.

The purpose of the research is to address the underutilization of electric machine-based propulsion in transportation despite its numerous advantages over conventional internal combustion engines (ICE), such as reduced emissions, lower fuel costs, and improved control and operation. To achieve this goal, the study reviews state-of-the-art energy sources, storage devices, power converters, and control strategies used in electric vehicles (EVs). It particularly focuses on the implementation of the five-level charging scheme for Lithium-ion (Li-ion) batteries, which are considered a promising solution for electric vehicle power storage. The important results of this work include the advantages of a five-level charging scheme for a 1Ah, 3.7V Li-ion battery compared with conventional charging methods, i.e., superior efficiency (97.16%), lower temperature rise (1.5 degrees Celsius), faster charging times (around 40-43 minutes), and extended battery lifespan. The significance of these results lies in their potential to address key drawbacks hindering the widespread adoption of plug-in hybrid electric vehicles (PH EVs) by offering a practical solution for faster, more efficient, and safer battery charging. By isolating the battery during charging and optimizing the charging process, the proposed system not only enhances the performance of electric vehicles but also contributes to prolonging the battery life, thus promoting sustainability in transportation. Additionally, the experimental validation using MATLAB Simulink underscores the practical feasibility of the proposed charging system, providing a valuable contribution to the field of electric vehicle technology.

The aim of this study is to determine the functional dependence for the calculation of the re-quired power of the electric motor of the traveling mechanism of the overhead traveling crane on the load capacity and span. The set aim is achieved by solving the following problems: figur-ing out how to calculate the power of the electric motor of the overhead traveling crane mecha-nism by the traditional methodology; selecting constants known from the initial data and varia-bles that require additional calculation; collecting and arranging statistical data - values of varia-bles for overhead cranes of different spans and load capacities; determining regression equa-tions based on statistical data - functions of two variables from the load capacity and span; sub-stituting the equations for the power of the overhead traveling crane mechanism from the load capacity and span. In the process of solving the set tasks, it was found that the greatest difficulty is the determination of static resistance and crane mass. Traditional calculation of these parame-ters requires the use of additional reference data and making design decisions of high responsi-bility. When searching for regression equations, the cubic model is-used, which provides high accuracy and does not overload the equation with summands. The most important result is the derivation of the final expression for determining the motor power as a function of two varia-bles - load capacity and span. The importance of the obtained results is that the proposed meth-od of calculation significantly reduces the time for the selection of the electric motor in the de-sign of a new crane, because there is no need to calculate or select additional parameters that are included in the traditional calculation. The proposed regularity is easier to integrate into comput-er-aided design systems. Since the calculation was based on statistical data of cranes manufac-tured and successfully operating, the probability of erroneous calculation is practically excluded.

The objective of this work is to elucidate the mathematical foundations for optimizing the con-figuration of district heating system networks. Existing and most effective approaches to opti-mizing thermal networks based on minimizing heat losses were analysed, and principles and cor-responding mathematical tools were proposed to account for objective technical constraints im-posed on these district heating networks by regulatory requirements, both at the technological and urban planning levels. The goal is achieved by solving the problems of modeling the coor-dinates of nodes and the lengths of sections of thermal networks using instrumental means to determine the most rational positions of the branching nodes in terms of their coordinates to identify economically viable directions for laying each fragment of the corresponding networks. To make the proposed approach to optimizing thermal networks practical, additional mathemati-cal tools must be introduced to account for specific urban planning conditions and constraints imposed on heating systems, which must be considered in the design process. The most im-portant results are the obtained mathematical model of the district heating network, which allows for considering the actual technical conditions for connection to the networks and urban plan-ning conditions and constraints. The significance of the results obtained is that the application of the developed algorithm allows not only to reduce the total heat losses during the transportation of the heat carrier from heat sources to consumers but also, as a consequence, to increase the energy efficiency level of the entire heating system, reduce primary energy costs, and green-house gas emissions.

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%.

The purpose of the work is study of special asymmetric modes of new three-phase autotrans-former device for flexible connection of alternative current power systems. The universal model was developed for the device, containing two autotransformers - the main phase-shifting and the additional regulating autotransformer. The model allows studying both symmetric and almost any asymmetric modes of the considered circuit. It became possible to connect asymmetrically the loads in different phases of the regulating autotransformer, as well as arbitrary connect the regulating autotransformer itself to the hexagon taps. According to the calculated values of cur-rents, voltages and magnetic fluxes of the device the visual vectorial diagrams were constructed for the main and the regulating autotransformer, explaining specific of considered operating modes. It was shown that device’ currents in such modes contain symmetrical components of both zero and negative sequences. Also, at asymmetric connection of the regulating autotrans-former, the relative magnetic flux of the legs of the main and regulating autotransformers are asymmetrical, but in main autotransformer their sum is approximately equal to zero and magnet-ic flux practically does not escape into the surrounding space. Radically different situation is observed in the regulating autotransformer. The significant zero-sequence fluxes arise with the release of significant (about 50%) magnetic flux into the surrounding space. This requires spe-cial measures to be taken to limit its harmful effects on the operation of the autotransformer.

The purpose of the work is to design a hybrid screen designed to reduce the level of the magnetic field generated by double-circuit overhead power lines, to increase the efficiency of shielding the original magnetic field in residential buildings, to the level of sanitary standards and to reduce the sensitivity of the system to changes in system parameters. To achieve this goal, the structure of a hybrid screen was determined, consisting of a double contour active and a cable contour passive part. The developed hybrid screen is characterized by increased efficiency in reducing the magnetic field of industrial frequency. Designing a hybrid screen comes down to solving a minimax vector optimization problem, in which the vector objective function is calculated based on solution to Maxwell's equations in a quasi-stationary approximation using the COMSOL Multiphysics software package. The solution to the minimax vector optimization problem is calculated based on multi-particle swarm optimization algorithms from Pareto-optimal solutions taking into account binary preference relations. During the design of the hybrid screen, the coordinates of the spatial location of the two compensation windings, as well as the magnitude of the currents and its phases in the windings of the active screen, were calculated. The important results are theoretical and experimental studies on the effectiveness of the designed hybrid magnetic field shield generated by double-circuit overhead power lines. The significance of the results obtained lies in the fact that practical recommendations are given for a reasonable choice of the spatial arrangement of two shielding windings of a robust system of hybrid shielding of the magnetic field generated by double-circuit overhead power lines.

The aim of this study is to investigate the commutation processes of an asynchronous short-circuited electric drive for a centrifugal pump. The set goal is achieved by solving two tasks: an-alyzing the dynamic modes of connection to and disconnection from the network of the asyn-chronous motor of the centrifugal pump for a given power supply scheme; assessing the qualita-tive and quantitative indicators of the transient processes of the electric drive. Among the most significant results of the study, it is possible to highlight the ability to form practical recommen-dations on the operation peculiarities of electric drives for a wide class of mechanisms. The conducted research allowed asserting that in an electrical system with capacitors directly con-nected to the stator winding and during both the connection and disconnection of the drive mo-tor of the centrifugal pump, voltages significantly exceeding the nominal ones may occur. It has been determined that considering the harsh operating conditions of pump units, such overvoltag-es represent a danger to the motor winding insulation. During the motor disconnection, signifi-cant overvoltages on the stator windings are possible if, for any reason, the capacitor's capaci-tance exceeds the calculated base value for the applied motor. The practical significance of the obtained results lies in the fact that the assumption of the motor transitioning to intensive braking mode and subsequent hydraulic shock upon disconnection from the network due to self-excitation did not prove to be true. The electric drive provides braking under the action of the load torque without mechanical overloads.

The purpose of the work is to develop an algorithm for calculating currents in the asynchronized turbogenerator rotor windings when it operates at a power system with a variable load. Typically, synchronous turbogenerators of thermal power plants are used to maintain the balance of active and reactive power in the power system. But they cannot fully ensure the maintenance of bal-ance by switching to non-nominal modes: during periods of power consumption dips, reduce power to 50-70% and switch to under-excitation mode to compensate for reactive power. There-fore, it is promising to install asynchronized turbogenerators at power plants in parallel with syn-chronous turbogenerators, which remain stable over a wide range of changes in active and reac-tive power. The work analyzed data from the operation of asynchronous turbogenerators in dif-ferent countries. The subject of the study was an ASTG-200-2U3 asynchronized turbogenerator with two identical field windings. The goal of the work was achieved by calculating the field windings currents using the finite element method and modeling in the FEMM program when the load magnitude and nature changes. The most important results of the work are the proposed algorithm for calculating the asynchronized turbogenerators field currents depending on the load size and nature in order to maintain the frequency and voltage nominal values. The significance of the results obtained lies in the fact that practical recommendations have been obtained for choosing the asynchronized generator load angle depending on the load size and nature, includ-ing in the modes of consumption of reactive energy.

Inrush current in high-temperature superconducting (HTS) transformers is a little-studied phenomenon. After connecting to the power grid, a current flow through the windings which exceeding the critical current value of the superconducting tape. It may cause significant overheating and thermal damage of winding. The purpose of the study is to develop a mathematical model for calculating inrush current pulses in a HTS transformer and its verification by physical experiments. To achieve the goal of the study, a mathematical model has been developed that accurately represents the electromagnetic and thermal transient processes after HTS transformer is turned on at idling or under load. The model considers the critical parameters of the HTS tapes, the process of heating and cooling of the windings, quench characteristics, and the electrical and magnetic parameters of the transformer. Good compliance of the experimental results and mathematical modeling with a deviation of 1.99 % allowed us to verify the model. The most important result is the creation of a mathematical model of the HTS transformer at the moment of connecting to power grid. This model represents the temperature changing of the windings during the loss of superconductivity. The developed model can be used in the analysis and modeling of inrush current in designed and operating HTS transformers for any power. The obtained results are significant for determine the optimal starting characteristics, geometric and electrical parameters of HTS transformers. The proposed methods for reducing the inrush current ensure safe and reliable operation of the HTS transformer when switched on at idling or under load.

This publication provides a brief overview of the results of research work in the field of developing alternative methods, schemes, and algorithms of synchronous multi-zone modulation of signals of inverters of power con-version systems with reduced switching frequency of power switches. In particular, in the mentioned researches, the basic strategies, schemes, and algorithms of synchronous multi-zone modulation have been further devel-oped, modernized, modified, and disseminated in relation to new promising topologies of power conversion sys-tems, including: two-inverter-based electric drives with open windings of electrical motor; drive systems based on electric motor with two stator windings; dual three-phase electric drives of symmetrical and asymmetric type; five-phase power conversion systems, powerful six-phase systems based on four inverters, and two-inverter-based and three-inverter-based photovoltaic installations with multi-winding transformer. It is shown that the developed schemes and algorithms of synchronous space-vector modulation applied for control of inverter-based systems provide continuous synchronization and symmetry of the basic voltage waveforms of systems during the whole control range. It provides minimization of even harmonics and undesirable subharmonics (of the fundamental frequency) in spectra of the basic voltages of systems, leading to reducing of losses in systems and to increasing of its efficiency. Based on a comparative analysis of the integral spectral characteristics of the phase and line voltages of the systems, recommendations are formulated for the rational choice of schemes and algorithms of synchronous modulation for the relevant installations, depending on the modes of their operation.

The purpose of the work is to develop and analyze the operation of a thermal circuit based on the organic Rankine cycle (ORC) using low-boiling working substances of the fluorocarbon class when operating at high initial cycle parameters. This goal is achieved by energy analysis of single- and multi-stage thermal circuits of power plants with a turbine circuit operating on low-boiling fluorocarbon working substances, such as octafluoropropane C3F8 and decafluorobutane C4F10. It is proposed to integrate the ORC thermal circuit as an extension to a small-capacity gas turbine power plant (GTU), operating on synthesis gas after a biomass gasifier. The most im-portant results of the work are the possibility of implementing a cycle with a low condensation temperature of the medium, which allows, when using low-boiling working fluids, to significant-ly reduce the temperature of the heat removal process and, consequently, increase the efficiency of the cycle. The possibility of using the listed working substances in power plants with a turbine circuit, which until now have been used mainly as refrigerants for refrigeration and heat pump systems, has been shown. The significance of the results of the work lies in the fact that, based on the analysis of the energy complex, a circuit solution has been proposed and justified that can increase the energy efficiency of the power supply complex, increasing the volume of gen-erated electrical power and providing a number of technological and environmental advantages.

The use of municipal solid waste as a raw material for alternative fuel is a promising direction for waste recycling and substitution of solid fossil fuels. Therefore, selecting of fuel composition and studying of its properties is an urgent task. The aim of this work is thermal characteristics analysis of the combustible components of municipal solid waste, which are the most common in Ukraine, for further selection of a fuel composition that will satisfy the consumer's requirements. The goal is achieved by studying the thermal destruction of samples by thermogravimetry and differential thermal analysis when materials are heated to 1000 ºС in the presence of air oxygen. Paper, cardboard, plastic, biodegradable film, textiles, leather, wood were investigated in this work. The most important results are the received data on the characteristic temperatures of destruction stages, content of water, organic and mineral substances, ash, as well as the calculated values of rate and conditional thermal effect of decomposition of organic substances. Strong formation of gaseous substances was registered for samples of polyethylene and biodegradable film, polyethylene terephthalate and cotton fabric. These features should be considered in the technologies of production and combustion of fuel. The significance of the results also lies in the fact that it is recommended to use data on the thermal stability of materials in order to prevent their ignition during drying when developing fuel production technology. In addition, the calculated values of the conditional thermal effect made it possible to evaluate the thermal characteristics of the studied materials as components of solid alternative fuels.

This article is devoted to the methods for perfection of energy, economic factors, environmental factors and work modes of the ground source heat pump systems with the account of climate conditions. The purpose of the work is to predict and prevent freezing of the soil during long term of exploitation of the low-power and high-power ground source heat pump systems for jus-tifying rational conditions of implementation GSHP in Ukraine and South-East Regions of Eu-rope. This goal is achieved by solving the following problems: determining the energy-economic and environmental factors based on considering the work modes of the ground source heat pumps; evaluation of the operating efficiency of ground source heat pump systems based on minimizing fuel consumption and greenhouse gas emissions; perfection of solutions enable im-plementation of ground source heat pumps friendly to the environment and justifying rational conditions of implementation the ground source heat pumps for residential sector. The important results of the work are the obtained and analyzed data on the influence of energy and economic factors both environmental criteria on the work modes and scheme-constructive solutions of ground source heat pumps. Modeling of heat exchange processes in the soil around the soil tube shows that in order to avoid freezing of the soil, the minimum permissible specific number of vertical tubes should be at least 0.12–0.15 pieces/m2 of heated area. The significance of the re-sults consists in the possibility of using the results of numerical simulation for preventing freez-ing of the soil around ground pipes of the ground source heat pump systems.

Modern energy systems are often used as a medium for information transmission, including confidential information, which makes relevant the task of ensuring its security, which today is solved using not only cryptographic but also steganographic means that ensure concealment of the very fact of confidential information transmission. The steganographic method with code control of the additional information embedding possesses practical important qualities, but in its original form requires the presence of a container for successful information extraction, which is not always desirable in practice, while the known modification of this steganographic method allows blind decoding is characterized by an insufficient level of resistance to attacks against the embedded message. The purpose of this paper is to improve the efficiency of the steganographic method with code control of the additional information embedding and blind decoding. This purpose was achieved by identifying two factors that determine the occurrence of errors during blind decoding of additional information in the steganographic method with code control: variation of sub-blocks, and errors caused by attacks against the embedded message. We pro-pose the theoretical and practical rationale for codewords that provide the best level of re-sistance to both factors. The most significant result of the paper is a reduction in the number of decoding errors of the steganographic method with code control of the additional information embedding and blind decoding by 12.01% compared to the result known in the literature through a reasonable choice of codewords used to embed the additional information.

The aim of this study is to determine the energy-efficient dehydration regimes for agricultural products based on suspension heat treatment method. In order to achieve this goal, an electrical plant was designed, developed, tested, optimized and implemented, on the basis of which the research was carried out, applying in the drying process, namely the process of technological processing in suspension with the contribution of convection. The research was focused on the example of drying different agricultural products; in particular, the following products were selected as the main object of the research: hawthorn, apple, quince, pear and grape seeds. These agricultural products were selected as at the moment they were not fully exploited. Because of their rich content of vegetable oils with specific properties, they are of great interest to the food industry, traditional medicine, cosmetology, pharmacology, etc., and their drying using conventional methods is difficult, particularly because of defects and adverse reactions, which frequently occur in the technological processing. The main results obtained using the designed installation, are: reduction of the electricity consumption and the processing time, increase in the productivity and quality of the final products. The significance of the results obtained in the research lies in solving a number of problems currently faced by the processors, in connection with the improvement of equipment and increasing the efficiency of the drying process, mainly by increasing the energy efficiency, processing speed, quality of products and profitability.

Ensuring high and stable biogas output during digester operation is ensured by regulating and monitoring values of control parameters. The purpose of article is to develop model of process of functioning of digester during methane mono-fermentation of cow manure with establishment of values of control parameters. A solution to model was found to obtain dynamics of biogas yield, while experimental and simulated dynamics of biogas yield were as close as possible. The developed model is system of differential equations that describe changes in concentrations of substrate nutrients , methanogen biomass and dynamics of biogas output in digester . The system of differential equations was solved in Simulink package , obtaining dependencies and . The dependence was compared with results of studies conducted on laboratory biogas plant with digester with useful volume of 30 liters at temperature of 37°C with periodic substrate loading system. By selecting parameters of model, resulting function was compared with similar one obtained experimentally. It has been established that in model of digester functioning process during methane mono-fermentation of cow manure, following coefficients have following meaning: bacterial growth rate m3/(kg day); substrate assimilation ; bacterial growth rate m3/(kg day); rate of conversion of nutrients into biogas m6/kg. The obtained values of coefficients make it possible to carry out modeling of process of methane mono-digestion of cow manure and predict biogas yield at different initial values of concentration of methanogen biomass, concentration of substrate nutrients, digester volume, which is used in industrial biogas plants.

. The goal of the work is to create a new method for automatic re-tuning of PI controllers. It is achieved by solving the following problems. The first problem is to develop a method to identify a FOPDT estimation model by analyzing the dynamics of a control loop with a PI controller. The second problem is to demonstrate that the use of the estimated model allows to obtain better processes in control systems with PI controllers by comparing the resulting FOPDT model with a number of reduced models. The third problem is to develop a five-stage algorithm for automatic re-tuning of PI controllers. The fourth problem is to verify the software implementation of the developed algorithm. The most significant result was that the basis for estimating the FOPDT model in a loop with a Ziegler-Nichols tuned PI controller was the estimation the ratio of the delay to the time constant of the FOPDT model based on an assessment of the process overshoot. When the real control plant dynamics did not match with the dynamics of the FOPDT model this way was found effective for finding the optimal tuning of the PI controller. The significance of the results obtained was a structural robustness in case of estimated FOPDT model usage. The effectiveness of the procedure has been demonstrated on both linear and nonlinear models. The developed procedure is proposed to be used to automate the procedure of re-tuning SISO control systems when the control loop performance degradation has been detected.

. The purpose of the article is to substantiate the feasibility of using object contrast as an informative feature for the formation of images used in technical vision systems. This goal is achieved by studying the dependence of the contrast of objects in images on the viewing geometry and determining the conditions under which the greatest similarity of the compared images is ensured. The solution to the first problem is based on the presentation of reference information about sighted objects, taking into account the navigation parameters of mobile robots. By modeling in the MATLAB software environment for typical viewing conditions, selective images were obtained using randomly selected fragments from Google Earth Pro, the distribution of contrast values and the cross-correlation function of the original and selective images. The influence of viewing angles on the distribution of contrasts and the formation of the decisive function was determined. The studies were performed for viewing angles of -60˚, -80˚ and -90˚ for altitudes in the range from 500 to 600 meters. The most significant result is a model of a set of reference images, taking into account the influence of navigation parameters on the contrast of objects, as well as experimentally established dependences of the distribution of contrasts for typical viewing conditions. The novelty of the work lies in the fact that the procedure for generating images and the decision function using the contrast of objects has been further developed. This will significantly increase the efficiency of selection of objects with insignificant brightness characteristics.

The purpose of the work is to develop a synthesis method for the spatial and angular arrangement of magnetic field sensors in order to ensure maximum efficiency of a robust system for active shielding of the magnetic field generated by overhead power lines, and to reduce the sensitivity of the synthesized system to initial uncertainties in changes in the level of the initial magnetic field, as well as system parameters while working. To achieve this goal, the spatial location coordinates and angular position of all magnetic field sensors, controller parameters, and gain vector for the compensating windings are determined. A synthesis of the spatial location and angular position of magnetic field sensors is created to solve a minimax vector optimization problem in which the vector objective function is calculated based on the Biot-Savart’s law. Solution of the minimax vector optimization problem, calculated on the basis of optimization algorithms for a multi-swarm of particles from Pareto-optimal solutions, taking into account the parameters of binary relations. Significant results obtained on the basis of the developed synthesis method are the effectiveness of a robust active shielding system for magnetic fields generated, as a consequence, by power lines with a synthesized spatial arrangement and angular position of magnetic field sensors obtained in the process of theoretical and experimental research. The significance of the results lies in the fact that practical recommendations are given for the reasonable choice of spatial location and angular position of magnetic field sensors, the spatial arrangement of shielding windings of a robust magnetic field shielding system for various characteristics of power lines.

The aim of this study is to investigate and determine the effect of accounting for the non-uniform distribution of magnetic induction (by detailing the stator tooth model) on the calculation results of magnetic losses in the stator teeth of a switched reluctance motor in quasi-steady-state modes. To achieve this goal, dependencies of phase flux linkage, electromagnetic torque of the motor, and additionally, dependencies of the root mean square values of magnetic inductions in stator tooth elements on the rotor angle and current have been determined using the finite element method. An investigation of dynamic modes of the switched reluctance motor based on an improved simulation model has been conducted at various values of constant load torque. Dependencies of magnetic inductions over time for each stator tooth element for the studied quasi-steady-state operating modes have been obtained. Magnetic losses have been calculated, taking into account the maxima of the temporal dependencies of root mean square values of magnetic induction in stator tooth elements. The most important outcome is a quantitative assessment of the influence of the non-uniform distribution of magnetic induction on the calculated value of magnetic losses based on the detailing of the stator tooth model in the operational modes of the switched reluctance motor compared to the traditional approach. The significance of the work lies in developing an approach to refining the calculation of magnetic losses by considering local saturation in the magnetic circuit during the operation of the switched reluctance motor.

The objective of the study is to develop recommendations for accounting during the design stage and the feasibility of operating a magnetic fluid seal with a significant eccentricity of the rotating shaft relative to stationary pole attachments. This goal is achieved through conducted experi-mental research, the selection of necessary equations, boundary conditions, assumptions, and physical properties of the magnetic fluid when constructing a numerical mathematical model of the working gap of the magnetic fluid seal. The most important results of the study include ob-tained and analyzed distributions of the magnetic field, velocity field, and pressure in the mag-netic fluid, as well as the evaluation results of the impact of absolute and relative shaft misa-lignment in the magnetic fluid seal, centrifugal forces arising during shaft rotation, on the re-tained pressure drop by the seal. A significant reduction in the retained pressure drop occurs at an eccentricity of up to 40% of the working gap, and with further increases in eccentricity, the rate of pressure drop reduction slows down. The significance of the results lies in the potential utilization of the provided numerical model, as well as the outcomes of physical and mathemati-cal experiments, in the development of a magnetic fluid seal operating with significant misa-lignment between the rotating shaft and the housing. The dimensionless dependencies obtained allow for consideration, during the design stage, of the reduction in retained pressure drop with shaft eccentricity, taking into account the magnitude of the working gap, magnetic induction, and linear velocity.

The purpose of the work is to develop continuous mathematical models of power factor correctors for switch-mode power supplies. The models are designed to solve optimization problems aimed at increasing the energy efficiency of these devices. This goal was achieved by developing a universal continuous averaged model of switch-mode voltage converters, which are an integral part of any active power factor corrector. State-space averaging method was proposed for constructing such a universal model. It has been shown that such a model adequately reproduces the processes in any of the main types of DC-DC voltage converters. The possibility of constructing a mathematical model of an active power factor corrector based on the proposed universal model of a DC-DC voltage converter is substantiated. The features of the structures of active power factor correctors for switching power supplies are considered and the problems that arise when studying their energy efficiency are shown. By simulation in the time domain with using the constructed model, diagrams of transients of the power factor corrector during load and primary network voltage disturbances are obtained. The most important result is the creation of a universal continuous mathematical model of switching voltage regulators. This model, unlike previously proposed models, is suitable for use in the analysis, modeling and design of any power factor correctors without the need to modify it in each specific case. The significance of the results obtained lies in accelerating the design process of active power factor correctors built on the basis of any type of pulsed DC-DC voltage converters. The developed model is intended for use in the Micro-Cap electronic circuit analysis program. However, since it is ultimately a software module in the SPICE language, this model can be used in many circuit analysis programs that support this language.