AIM. To determine optimal modes for methane decarbonization, as well as to assess CO₂ emissions during subsequent combustion of the pyrolysis gas, including together with the natural gas in various ratios.
METHODS. The processes of thermochemical conversion of methane into hydrogen and condensed carbon in a reactor with external heating of the walls were considered. The thermal energy required for gas pyrolysis is obtained by burning a mixture of air and part of the pyrolysis gas, which is free from solid carbon particles. When performing numerical studies of pyrolysis processes, a kinetic model of one-dimensional flow of the reacting mixture was used with an external supply of thermal energy through the walls of an axisymmetric channel (tubular reactor).
RESULTS. The mechanism of chemical interaction during the thermal decomposition of methane was developed, taking into account the formation of condensed carbon in the temperature range from 1000 to 1200 °C. The main energy indicators and the composition of pyrolysis gas were determined at various values of the pyrolysis temperature and the degree of carbon conversion.
CONCLUSION. Carbon dioxide emissions from the combustion of pyrolysis gas, including together with the natural gas, were assessed. When developing pyrolysis technologies and applying them on an industrial scale, it is advisable to use part of the resulting pyrolysis gas with a high hydrogen content to provide thermal energy for the processes of thermal decomposition of the feedstock. According to the calculations, the share of this part reaches ≈ 35% of the total amount of pyrolysis gas. This approach, as opposed to burning the natural gas for this purpose, significantly reduces CO₂ emissions. The combustion of the resulting pyrolysis gas, even without removing residual hydrocarbons, is characterized by currently quite acceptable CO₂ emission factors of ≈ 7-25 t CO₂/TJ.

RELEVANCE In modern Russia, an important condition for the development of the Far North and Far Eastern regions is to provide these regions with electricity. In remote areas with increased wind potential, the use of wind power plants, the main structural elements of which are made of polymer composite materials (PCM), is promising. The most dangerous operational defect of the PCM is shock damage: due to hail strikes or pieces of ice that broke off during heating of the blades, as well as lightning strikes. Such defects, which are difficult to detect during visual inspection, can significantly reduce the strength and service life of the structure. At the stages of technology development and design certification, the use of modern methods of non-destructive testing is required.
PURPOSE. To evaluate the possibilities of X-ray computed tomography for the diagnosis of structural elements made of PCM with impact damage.
METHODS. After applying a low-speed impact to fragments of the blades of the wind turbine, a visual inspection and measurement of the size of internal injuries are carried out on a Phoenix V |Tome|X X-ray computed tomograph.
RESULTS The nature of the damage inflicted with different impact energies on the most critical areas of fragments of the airfoil blades and the stringer panel is investigated. The depth and area of damage have been determined. The nature and size of internal injuries were studied using an X-ray
COMPUTED tomograph. conclusion. The results obtained allow us to estimate with high accuracy the size and location of impact damage, which can be used in strength calculations.

RELEVANCE the research is to develop a new system for assessing the technical condition of power oil-filled transformer equipment of distribution networks.
OBJECT. To increase the accuracy of assessing the technical condition of power oil-filled transformer equipment (POTE) of distribution networks through the use of machine learning methods. Currently, an increase in the volume of analyzed information about the state of the management system of distribution networks leads to significant changes in the choice of data processing methods. The use of machine learning methods is associated both with the need to apply operational experience (in the form of expert assessments) and to obtain objective assessments of the condition of transformer equipment of distribution networks from instrumentation and sensors.
METHODS. This work uses research methods such as mathematical modeling and the method of paired comparisons. As an example, we consider the oil-filled power transformer TMN-6300, its diagnostic parameters, external and operating parameters. The technical condition of the TMN-6300 transformer is assessed and a predictive model is created based on the existing monitoring system and machine learning methods, which make it possible to formalize expert knowledge and automate the process of data processing and analysis.
RESULTS. A database has been created to assess and predict the technical condition of POTE of distribution network management systems. The algorithm for predicting the technical condition of POTE of the technical equipment in the form of an artificial neural network model was tested in the developed assessment system.
CONCLUSION. The results of assessing and predicting the technical condition of POTE of the metering system of distribution networks obtained in this work prove the unconditional relationship between the parameters of the metering system and external, operating parameters. The data obtained as a result of modeling helps to increase the accuracy of forecasting the technical condition and determine the longterm prospects for the functioning of POTE the equipment management system, timely maintenance and repairs over the course of years and months.

RELEVANCE. The challenges of creating modern permanent magnet synchronous motors require solving technical problems in conjunction with economic realities. Due to the use of permanent magnets in the construction of synchronous motors, their cost limits their industrial application. Therefore, there is an urgent issue of optimizing the design of synchronous motors, which can be solved by changing the topology.
TARGET. The goal is to create more economical permanent magnet synchronous motors (PMSMs) in low-power electric vehicles. It is planned to implement a new method for constructing PMSM. This solution will reduce weight and size parameters and increase specific power, which are important indicators for electric transport.
METHODS. To modernize modern synchronous motors, a complex topological optimization method based on a genetic algorithm is proposed.
RESULTS. A computer model was obtained in the form of calculation of electromagnetic fields in the stator and rotor of a synchronous motor with permanent magnets.
CONCLUSION. Modeling the parameters of synchronous motors with permanent magnets has a low degree of development in the domestic mechanical engineering due to the lack of developed infrastructure in the field of low-power electric transport; the creation of domestic developments in this area is of a strategic nature.

Currently, the commissioning of power plants based on renewable energy sources (RES) using inverters is becoming widespread. However, these power plants do not participate in maintaining the stability of the power system during emergency disturbances, since they are switched off by technological protections when a disturbance occurs. In the future, when power plants based on renewable energy sources become widespread, ensuring the possibility of their participation in maintaining sustainability will significantly increase the reliability of the energy system. A preliminary assessment of the effectiveness of participation in maintaining sustainability should be carried out through computer modeling.
THE PURPOSE: To realize the possibility of participation of RES-based power plants in ensuring reliable and sustainable operation of the power system, as well as to realize the possibility of performing a preliminary assessment of the effectiveness of the proposed method.
METHODS. In this paper, the application of virtual synchronous generator technology is proposed to realize the possibility of participation of RES-based power plants in ensuring the reliability and sustainability of the power system. Also, a method of modeling the virtual synchronous generator in Matlab software package is proposed.
RESULTS. The technology of virtual synchronous generator is proposed, which with the use of inverter, electric energy storage and appropriate control system can provide the increase of dynamic stability of power system. A method of modeling the virtual synchronous generator in Matlab software package is proposed. The results obtained allow us to conclude that the constructed model of a virtual synchronous generator is efficient, maintains the stability of the system and ensures correct control of the inverter, as a result of which the parameters of the electrical network are maintained within acceptable limits. The resulting computer model can be used in further research.
CONCLUSION. The technology of virtual synchronous generator allows to imitate in the inverter the inertial and damping characteristics of the traditional synchronous generator, and the proposed computer model will help to evaluate the effectiveness of this technology when implemented in the power system.

RELEVANCE. Thermal imaging control is used to monitor the technical condition of electrical equipment, as well as contacts and contact connections of switching devices, which allows to increase the efficiency of work.
OBJECT. Timely detection of defects of contacts and contact connections of low-voltage switching devices to prevent emergencies.
METHODS. Determination and control of technical condition of electrical equipment, contacts and contact connections of apparatuses in real time by means of indicators and thermal imaging control.
RESULTS. The values of contact heating temperatures from material and type of contact connections were analysed. The criteria for estimation of the state of contacts of switching devices with the help of indicators of their state have been determined. The optimum values of loading coefficients of the circuit breaker in moulded case VA04 and contactors KMI and KTI are obtained. Emergency cases at the industrial object are shown, which prove the necessity of application of indicators and thermal imaging control as one of the tools of automation of technical condition control of low-voltage electrical equipment.
CONCLUSIONS. The offered noncontact method of estimation and control of technical condition of electrical equipment, contacts and contact connections of devices in real time with the help of indicators and thermal imaging control allows both to receive data in real time mode and to increase inter-repair periods for power equipment and to increase reliability of operation of the whole system.

RELEVANCE: The problem of hazardous working conditions in Russia attracts attention due to an increase in the proportion of workers exposed to negative impacts on their health. Of particular interest is the analysis of the air environment as the main factor influencing human health. 32.2% of workers in hazardous working conditions are exposed to airborne factors, which leads to occupational diseases. To reduce the harmful effects of the air, it is necessary to clean it from harmful components. A promising device for air purification is an electric precipitator.
PURPOSE: The study is aimed at selecting and optimizing electric precipitators for air purification in industrial premises. The goal is to determine the most effective design of an electric precipitator for cleaning the air environment of industrial premises.
METHODS: The analysis is carried out on the basis of statistical data, the results of studies of electric precipitators of various designs for cleaning the air from dust, harmful gases and microorganisms. The results are used for comparative analysis.
RESULTS: The study reveals that different designs of electrostatic precipitators demonstrate different effectiveness in air purification depending on the type of design. The design of corona electrodes affects ozone generation. It has been established that two-zone electrostatic precipitators with needle corona electrodes on the negative corona can significantly reduce ozone emissions. Wet electrostatic precipitators have regeneration, and the presence of several stages increases the cleaning efficiency. Electrostatic filters do not generate ozone and can be used in explosive low-volume areas.
CONCLUSION: The study confirms that the choice of electrostatic precipitator should depend on the specifics of production and the volume of the room. For explosive environments, electrostatic precipitators should be preferred, while for large areas, a wet multi-stage electrostatic precipitator is recommended. Electrostatic precipitators-ozonizers can be effective for air disinfection. Summarizing the results allows us to conclude that it is important to choose the appropriate type of electrostatic precipitator to ensure optimal air conditions for the safety of workers.

An algorithm for eliminating aperiodic components from short circuit (SC) currents is proposed. The algorithm is implemented by computer technology and allows you to determine the location of a short circuit and phase loss in 0.5 - 0.6 milliseconds. During such a time interval, saturation of the magnetic circuits of current transformers (CTs) does not occur, and the processors receive undistorted information from the CTs. To implement the algorithm, four measurements of instantaneous current values, separated by equal time intervals (sampling intervals), are sufficient. Elimination of aperiodic components increases the accuracy of determining the location of the fault. The algorithm can be used to determine the location of phase failure, and in digital relay protection based on measuring currents and voltages.

In the modern world, the problem of the ecological state of our planet is acute. The environmental situation depends on many factors, these include both natural phenomena and human actions. One solution to this problem is to replace traditional internal combustion engines with more environmentally friendly electric vehicles.
THE PURPOSE. The objective of this study is to analyze the internal structure of an electric vehicle, based on the training stand “Electric Vehicle Motor”, as well as to study the functions of this device, located at the Kazan State Energy University.
METHODS. The authors of the article processed and analyzed the capabilities of modern laboratory equipment that simulates the operation of a particular component of an electric vehicle.
RESULTS. The technology of the laboratory bench operating the electric vehicle, together with the DVT Customer software, allows for full control of the electric motor, as well as monitoring and changing a large number of parameters that affect the operation of the entire device as a whole.
CONCLUSION. Since electric vehicles are gaining more and more popularity every year, the demand for people capable of diagnosing, repairing, and even improving existing ones and developing new components and assemblies in the field of electric vehicles is growing significantly. Using the “Electric Vehicle Motor” stand for teaching technical subjects and conducting research work can serve as a good basis for the formation of a general knowledge base about electric transport, its structure, the operating principle of all the main elements, monitoring and diagnostics of an electric vehicle.

RELEVANCE of the research. The global trend of decarbonization of the national economies of the leading countries of the world implies an increase in energy production due to renewable energy sources and hydrogen. The most environmentally friendly way to produce hydrogen is the electrolysis of water using wind and solar energy. Combined production of thermal, electric energy, hydrogen and oxygen carried out by energy complexes ensures reduction of harmful emissions and increase of their economic efficiency.
METHODS. In solving this problem, the method of computational experiment was used, taking into account the geographical and climatic data of the location of the energy complex, as well as the nature of consumption of thermal, electric energy and hydrogen. The calculation was implemented in Visual Basic.
RESULTS. The article describes the relevance of the topic, examines the influence of the installed capacity of photovoltaic converters, geographical, climatic and cost characteristics on the efficiency of the energy complex.
CONCLUSION. The structure is determined and a schematic diagram of a multi-purpose energy complex is proposed. A methodology for calculating quantitative and economic indicators of the installation has been developed. In the course of the study, it was noted that there is an optimal value of the installed capacity of a photovoltaic installation, further increase of which is inexpedient from an economic point of view. It was also determined that the combination of hydrogen gas stations based on solar installations with traditional sources of energy supply can reduce the cost of hydrogen produced, which in the future may be a solution to the problem of creating a hydrogen infrastructure.

The purpose of this article is to review the existing reliability problems of pipeline systems of power complexes. The article considers the existing statistical and logistics systems, which allow to process diagnostic information when assessing the technical condition of pipelines. Modern diagnostic methods are mainly based on the use of vibration, sound, and ultrasonic sensors. The presence of a defect in a pipeline is determined by analysis of the amplitude of a diagnostic signal. Higher efficiency in detecting defects was shown by probability-statistical methods of signal analysis, which are based on chaos theory. One such method is entropy analysis. Analysis of modern signal processing methods has shown that methods based on chaos theory are the most effective. The possibility of using entropy indices as sensitive diagnostic signs is considered. Comparative analysis of signal processing was carried out using entropy methods (Shannon entropy, Kolmogorov entropy) and using known statistical and logistic methods (Fourier Transform, Wavelet Transform, Hilbert-Huang Transform). The analysis results showed that entropy indicators respond to a change in signal structure caused by the presence of a defect in the pipeline or Entropy analysis is a promising method of processing diagnostic signals when assessing the technical condition of pipelines.

THE PURPOSE. Development of digital models to determine the modes of double ground faults in 6-10 kV overhead signaling lines supplying signaling, centralization and automatic blocking facilities.
METHODS. To create the models, methods of multiphase modeling of electric power systems were used, based on the use of lattice equivalent circuits from RLCelements connected according to complete graph circuits. For modeling, the industrial software package Fazonord, developed at the Irkutsk State Transport University, was used.
RESULTS. The developed models provide correct accounting of all factors influencing the modes of double ground faults, including increased electromagnetic influences of the traction network. In contrast to known approaches, the dynamics of changes in these influences caused by variations in traction loads during train movement are modeled.
CONCLUSION. The proposed approach to modeling double ground fault modes is universal and can be used for standard traction power supply systems, as well as promising high-voltage traction networks. The results obtained can be used in practice to configure relay protection devices for overhead signaling lines in order to reliably detect double ground fault modes and take measures to eliminate them. In addition, the modeling methodology presented in the article can be used when selecting measures to improve the reliability of power supply to signaling and automatic blocking facilities that ensure the safety of train traffic, as well as to develop methods and algorithms for determining distances to places of double ground faults in overhead power lines feeding signaling facilities , centralization and autoblocking. The presented results confirmed the effectiveness of the proposed approach for modeling double ground fault modes.

RELEVANCE. In the modern world, on the verge of global climate change, the search and implementation of alternative energy sources become particularly significant. Hydrogen energy is one of the most promising directions, offering a revolutionary approach to the decarbonization of various industrial sectors. The development of technologies related to the production, storage, and use of hydrogen opens new horizons for creating a sustainable and environmentally friendly energy infrastructure.
OBJECTIVE. To review the technological state of hydrogen refueling stations (HRS), analyze the latest global trends and developments in this area, identify factors contributing to the efficiency of HRS components, and present thermodynamic principles of hydrogen fuel use. To outline the main problems associated with the need for widespread implementation of hydrogen infrastructure and to identify potential directions for their resolution. To develop suggestions for creating a modular layout of a container-type hydrogen station, which will allow a flexible approach to organizing hydrogen infrastructure with the possibility of rapid scaling and adaptation under various operating conditions.
METHODS. Based on the use of literature data. The method of prototyping an autonomous hydrogen refueling station was used, and mathematical calculations of thermodynamic processes occurring in the components of HRS were conducted.
RESULTS. Studies in the field of technological state of stations have been examined and systematized, and development trends have been identified. The main components involved in the operation of a hydrogen station are described. Thermodynamic processes of hydrogen fuel use that contribute to a significant reduction in energy consumption of hydrogen stations have been investigated.
CONCLUSION. The hydrogen station combines efficient conversion of hydrogen into electricity, minimization of emissions, energy independence, and flexibility in energy storage. Determining the optimal operating parameters of HRS equipment based on the thermodynamics of processes, considering the specifics of temperature regimes of Russian regions, is important for reducing costs and increasing the energy efficiency of hydrogen fuel systems. The proposed structure of the container-type HRS is an optimal platform for subsequent modernizations and innovations in the field of hydrogen technologies.

THE PURPOSE. An experimental method is used to evaluate the effect of the temperature of inert gases on the rate of thermal decomposition of waste rubber products (fragments of a car tire) upon their direct contact.
METHODS. The research was carried out on a test firing stand at a stationary mode of gas movement in the temperature range from 300 °C to 500 °C. The initial weight of the rubber was 4 grams. The thermal decomposition of rubber was carried out due to the thermal energy of inert gas released during the combustion of a propanebutane mixture with air at α = 1.1...1.15. The consumption of fuel and oxidizer remained constant, the change in gas temperature was carried out by heat exchange of hot gases and water in the heat exchanger.
RESULTS. Metodology of conducting experiments, the object of research under the study, results of the research and their analysis are described in the article. The main parameters were selected: the rate of decrease in rubber mass depending on the temperature of the gases, the limiting value of the gas temperature at which sulfur in solid form remains in the decomposed part of the rubber.
CONCLUSION. It was found that with increasing temperature of the inert gas, the rate of thermal decomposition of rubber increases. When rubber is in a gaseous environment in the temperature range from 450 ⁰C to 500 ⁰C, the sulfur content in the solid residue remains practically unchanged. The average rate of pyrolysis was 0.02 kg/h, which is 6 times higher than the rate of pyrolysis in the retort (0.003 kg/h).

RELEVANCE. The authors research the local utilization of wastewater heat (in close proximity to the place of their formation) based on a heat exchanger. To select rational characteristics of the heat exchanger and correctly assess the potential energy effect, it is necessary to take into account the influence of the operating conditions of the device (duration of individual use of the shower, mass flow of heated and heating water, temperature of heated water at the inlet to the heat exchanger, temperature of the flow at the moment the device is turned on).
THE PURPOSE. The purpose of the work is to research the dependence of the efficiency of wastewater heat utilization on the operating conditions of the heat exchanger and to identify the parameters that have the greatest impact on the effect of energy-saving measures.
METHODS. Based on a verified mathematical model of the thermal operation of a recovery heat exchanger, the temperature distribution inside the flows of the heated and heating water in time is calculated (from the moment of switching on until reaching a stationary operating mode). Based on the data obtained (the temperature of the heated water at the outlet of the heat exchanger at each point in time), the absolute and relative heat savings are determined under various operating conditions.
RESULTS. The influence of the non-stationary phase of the heat exchanger operation on its energy efficiency is considered. For a specific heat exchanger configuration, the time required for the device to reach a steady state of thermal operation is determined. It was revealed that the greatest influence on the relative and absolute savings of thermal energy is exerted by such operating conditions as mass flow and temperature of heated water at the entrance to the heat exchanger. The temperature of the flow at the initial moment of time has the least influence on the energy effect.
CONCLUSION. The operating conditions that have the greatest impact on the effect of local wastewater heat recovery are determined. The need to take these conditions into account when designing a heat exchanger and choosing its optimal parameters has been confirmed.