The article describes to eliminate possible errors in the supply of cylinders with sulfur hexafluoride and cylinders with carbon tetrafluoride to high-voltage substations for refueling switching devices such as high-voltage switches, voltage transformers, etc. Conduct an analysis of possible erroneous supplies of the two above-mentioned gases at the substation. Make an analysis of possible residuals (or shortfalls) of gas cylinders after refilling. Make an assumption about the reasons for the appearance of possible residues. Give recommendations for overcoming possible problems. Make the appropriate calculations. Propose a formula (table) for recalculating the consumption of both types of gases. Make a table for calculating the actual values of the number of supplied cylinders, related to the discreteness of the volumes of the cylinders and the switching devices themselves. Draw appropriate conclusions and make recommendations. To achieve this goal, a method was used to calculate the state of an ideal gas using software for working with spreadsheets. The article reflects the relevance of the topic and discusses the features of refueling high-voltage SF6 equipment in various climatic conditions (below minus 40-49°F). An analysis of typical ratings of high-voltage switches used at highvoltage substations was carried out. A graph is presented for converting the molar fraction (contributing to pressure) of gases into the mass fraction. A sample calculation of the number of cylinders is presented for two commonly encountered volumes of switching devices and fortyliter gas cylinders for several standard cylinder filling ratios. Presumptive conclusions are presented regarding the assessment of real errors when sending gas cylinders for refilling switching devices. The article offers an understanding of the sequence of problems associated with incorrect calculations and a complete methodology for calculating the correct volumes (mass) of gas depending on the actual types of devices used, depending on the volume of supplies pieces of equipment.

TARGET. The purpose of this work is to develop a standard design of an installation for testing personal protective equipment. According to the standard design, the installation should be more functional and cheaper than existing analogues, while its design should fully comply with the requirements of regulatory and technical documentation (Rules for the installation of electrical installations, Rules of labor protection when working in electrical installations).

METHODS. According to the developed standard design, it implies the use of АИИ-70 test devices, which have been put into storage as a result of equipping electrical laboratories with more mobile modern analogues. The secondary use of test devices freed from

the operational load makes it possible to eliminate the cost of purchasing a high-voltage source included in its design, thereby reducing the total cost of the project. The project provides that the products from which the installation is assembled include products from the retail range of electrical products.

RESULTS. The installation, assembled according to the developed project, provides the opportunity to conduct the largest number of types of tests among analogues. The cost of installation assembled according to the developed project is several times lower than analogues. Full compliance of the installation with the requirements of regulatory and technical documentation ensures the safety of high-voltage tests and allows it to be registered with supervisory authorities.

CONCLUSION. A stationary installation for testing personal protective equipment has been assembled at the Kazan State Energy University. Testing it during tests of dielectric gloves and a high voltage indicator proves the operability of the installation assembled according to the developed project.

The relevance of the work lies in the study of the effect of calcium deposits of various thicknesses on the inner walls of the pipeline on the parameters of its own vibrations.

OBJECTIVE: To construct a mathematical model of a steel pipeline without deposits and with calcium deposits of various thicknesses on its inner walls. To perform a modal analysis of the natural vibrations of the steel pipeline. Theoretically confirm the dependence of the change in the oscillation frequency of the pipeline when exposed to sediments.

METHODS. The paper highlights a method for analyzing the natural frequencies of the pipeline using the acoustic method of non-destructive testing, since it can be implemented with one-way access and does not violate the integrity of the object of control. In solving this problem, the method of mathematical analysis in the software package of finite element analysis was used. results. The article describes the relevance of the topic, discusses the main methods of non-destructive testing, and defines Lamb waves. A mathematical model of a steel pipeline section with out internal deposits and with calcium deposits of 5 different thicknesses has been constructed.

CONCLUSION. Calculations have shown that the natural vibration frequencies of the pipeline without deposits and with calcium deposits change in the direction of increasing values, the frequency increase occurs in waves. The highest frequency values are obtained when modeling calcium deposits with a thickness of 10 mm on the walls of the pipeline.

Testing the operation of protection devices against parallel arc breakdown and spark gaps in the event of a ground fault

THE PURPOSE. Develop a laboratory rig for testing parallel arc fault and spark gap protection devices for tripping in the event of a ground fault. Conduct laboratory rig tests with subsequent development of requirements for the use of parallel arc fault and spark gap protection devices for tripping in the event of a ground fault.

METHODS. Mathematical and statistical methods of analysis were used to achieve the stated objective. Laboratory tests of parallel arc fault and spark gap protection devices for different network parameters for correct tripping in the event of a ground fault.

RESULTS. Laboratory tests of parallel arc fault and spark gap protection devices for correct tripping in the event of a ground fault were conducted with different network parameters. The oscilloscope recorded the shape of the voltage and current curve in the event of a ground fault and the tripping time of the devices. The tested devices demonstrated the ability to recognize and disconnect a ground fault. The tripping time of the devices varies, however, does not exceed the established requirements.

CONCLUSION. A laboratory stand has been developed for testing parallel arc breakdown and spark gap protection devices for operation during a ground fault. This stand makes it possible to test devices for adequate operation during a ground fault with subsequent certification. The tests conducted demonstrate the need to develop mandatory requirements for the device to standardize their operating algorithm. Therefore, the use of this protection device can contribute to safer operation of low-voltage electrical networks by preventing emergency situations and reducing the risk of fires. This is an important technical aspect for improving the reliability and safety of power supply.

RELEVANCE. There are a large number of heat exchangers in operation enterprises that operate under various temperature conditions. Steam, hot water, heated products of oil refining and other industries, which may contain oxides of iron, aluminum, calcium sulfate silicates, etc., are used as a heating agent. The efficiency of the heat exchange equipment depends on the condition of the heating surfaces. Contamination of these surfaces with various deposits dramatically reduces the heat transfer coefficient, which leads to a significant increase in heat consumption. The nature of the deposits depends on the properties of the heating agent and the heated medium.

THE PURPOSE. The purpose is to assess the possibility of controlling deposits on the surfaces of heat exchange equipment by the free oscillation method. The presence of deposits changes the mass of structures and, consequently, the natural frequencies of vibrations, the analysis of which can determine not only the presence and thickness of deposits, as well as their appearance.

METHODS. The paper shows the results of experimental studies conducted using a hardware and software package and calculations of natural vibrations of the surfaces of heat exchange equipment in the ANSYS software package to identify their dependence on the thickness and density of deposits. A plate, a pipe, and a pressurized pipe were modeled as heat transfer surfaces.

RESULTS. The results obtained experimentally and computationally coincided, and it was concluded that the free oscillation method makes it possible to determine not only the presence of deposits on heat exchange surfaces, but their thickness and appearance.

CONCLUSION. The free oscillation method can detect deposits in a timely manner and monitor their condition, which in turn will, reduce overall operating costs, increase energy efficiency and extend service life.

RELEVANCE. The paper presents a method for calculating the temperature parameters and service life of cable lines (CL) with a voltage of 10 kV for various types of insulation and operating conditions. Dependencies have been developed that are recommended for clarifying the parameters of the CL, taking into account different operating modes. The results of the study can be used for practical application and will contribute to reducing the number of accidents resulting from thermal breakdowns of CL due to incorrect selection of CL parameters.

PURPOSE. To investigate the temperature parameters of 10 kV CL, taking into account various methods of laying them and load factors for the climatic conditions of the Republic of Tatarstan.

METHODS. Methods for calculating the temperature parameters of CL and their service life, methods of statistical data processing, and methods for approximating functions are used. The ELCUT software package is used to visualize the results obtained during calculations. results. The results of calculations of the temperature parameters of 10 kV CL with paper-impregnated insulation (BPI), polyvinyl chloride plastic (PVC) insulation and polyethylene (PE) insulation during their laying in air, in the ground, in the ground in a pipe, taking into account the load coefficients of cable lines, are presented. The results of calculations of the service life of the CL are shown. The values of the optimal load coefficients of the CL are determined to reduce the rate of thermal aging of insulation under various operating conditions. conclusion. The results of the conducted research and calculations can be used to evaluate and select the optimal load of 10 kV CL at the stages of operation and design of power supply systems.

RELEVANCE of the study lies in the development of system for the short-term forecasting of power consumption by the enterprise of the oil and gas industry with consideration of technological factors and interpretation of their influence on the result of the forecast.

THE PURPOSE. To consider the problems of short-term forecasting. To test the applicability of the multi-agent approach to determine the features used to build a machine learning model of short-term forecasting of power consumption. To build machine learning models. To study the influence of technological factors on the accuracy of forecasting of power consumption. To apply the SHapley Additive exPlanations and analyze its interpretation of the forecasting results.

METHODS. Pre-processing of the dataset, construction and testing of machine learning models were made in the programming language Python 3 using opensource libraries Scikit-Learn, XGBoost, LightGBM, Shap.

RESULTS. The article describes the relevance of the topic of short-term forecasting of power consumption by the enterprise of the oil and gas industry within the ESG-approach. The method of selecting the features used using a multi-agent approach to build a machine learning model was developed. Machine learning models were built. Experimentations with the consideration of different features were made. Interpretation of results using SHapley Additive exPlanations was made.

CONCLUSION. The use of technological factors of power consumption of compressor yards and natural gas air coolers allowed to increase the accuracy of forecast of power consumption from 8.82 % to 3.65 %. The application of the SHapley Additive exPlanations allows to interpret the results of machine learning models and confirms the need to consider technological factors in the task of short-term forecasting of power consumption of oil and gas industry.

RELEVANCE. The length and complexity of the geography of medium voltage cable lines is at a high level. Such lines extend underground, on supports in the air. In order to constantly maintain the reliability of city power supply at a high level, any interruptions and accidents should be promptly corrected.

TARGET. The main goal of the work is to develop the theory of medium voltage CL research, to practically and theoretically substantiate the search for the most convenient and effective installation for CL diagnostics, to study and develop possible modifications of CL diagnostic installations.

METHODS. A variant of CL diagnostics based on the CPDA-60 installation is proposed, which makes it possible to find and localize the places where defects occur in the insulation based on the measurement and analysis of partial discharges (PD). Suitable for insulation monitoring in all types of high voltage cables. The CPDA installation can be used when testing new cable lines being put into operation, and to analyze the condition of old cables in operation.

RESULTS. Cable lines require an integrated approach to diagnostics and monitoring, since the reliability of modern authentication systems for the generation and distribution of electricity is largely determined by the electrical reliability of electrical equipment. Technical diagnostics of equipment is a key link, the quality of which determines the efficiency of the processes of organizing production activities, strategic planning and renovation of electric grid assets.

CONCLUSION. The study and analysis of the presented data and research allows us to form a conclusion regarding the method of measuring and localizing partial discharges (PD) in power cable lines (CL) using the Online Wire Testing System (OWTS) diagnostic system. The OWTS system allows real-time measurements without interrupting cable lines, making it especially valuable to the energy industry. Thanks to the introduction of advanced technologies and signal processing algorithms, the method has high accuracy and sensitivity to minimal manifestations of private discharges, which allows not only to detect, but also to accurately localize the location of defects in the insulation. The use of this method can significantly increase the service life of power cables, reduce the likelihood of sudden accidents and, as a result, reduce the cost of repair and maintenance of electrical power equipment. Ultimately, improvements in diagnostic and monitoring techniques, including the method of measuring and localizing PD in power lines using OWTS, represent a significant step towards improving the reliability and safety of electrical power systems. This will not only reduce operating costs, but also ensure uninterrupted and high-quality power supply to consumers.

RELEVANCE of the study lies in the assessment of the impact that various carbon regulation instruments stimulating the achievement of national climate goals have on the development scale of different electricity and heat production technologies in Russia.

THE PURPOSE. To consider the change in the optimal technological structure of the electric power industry and district heating in Russia by 2050 assuming the introduction of various carbon regulation instruments in 2030.

METHODS. We used the developed at ERI RAS system technological model EPOS for the optimization of the energy technology structure in the Russian energy sector according to the criterion of the minimum total discounted costs for energy supply to the economy until 2050.

RESULTS. The article provides an analysis of the scale of changes in installed capacity and electricity production of various types of power plants in the UES of Russia, as well as changes in heat production of different heat supply sources by 2050 for 16 carbon regulation options and business-as-usual scenario. Also it describes the optimal technological structure in the electric power industry and district heating under the conditions of certain administrative, fiscal and economic instruments of climate policy. Carbon regulation options based on the corresponding increases in the installed capacity of power plants in the UES of Russia by 2050 are compared.

CONCLUSION. Decarbonization of the electric power industry in Russia will mainly occur by expansion of nuclear energy, heat production – by deployment of electric boilers, taking into account current forecasts of scientific and technological progress. At the same time, for carbon regulation options leading to a greenhouse gas emissions reduction by 30% relative to 2019 level, nuclear power plants could become the new dominant technology in the structure of electricity production instead of gas thermal power plants. The total increase in installed capacity of power plants in the UES of Russia by 2050 may differ by almost seven times for various carbon regulation options. Among the climate policy options considered, emission quotation and carbon taxes have the strongest impact on the technological structure of the electric power industry and district heating in Russia.

RELEVANCE. The relevance of this study lies in the need to preserve their design cooling efficiency during the operation of cooling towers, as well as to prevent a decrease in the mechanical strength of sprinklers as a result of the formation of deposits that contribute to the deterioration of heat exchange conditions and strength characteristics of structural elements.

OBJECT. Increasing the efficiency of heat transfer in the cooling processes of circulating water when using tower cooling towers at thermal power plants.

METHODS. To achieve these goals, comprehensive studies of samples of circulating water and sediments formed on the sprinklers of tower cooling towers were carried out using classical methods of physico-chemical and elemental analyses, as well as sediment studies using X-ray diffraction analysis and electron microscopy.

RESULTS. The relationship between the parameters of cooling water and the nature of sedimentsformed on the sprinklers, in particular the proportion of crystalline and non-organic ones, has been tracked. A method of highly effective pretreatment of source water with biodegradable biocidal reagents was considered in detail, since the existing disinfection method does not prevent the development of colonies of microorganisms on cooling tower sprinklers. The effectiveness of the use of the biodegradable THPS reagent, which is relatively safe for the environment in comparison with oxidizing biocides and classic bromine-based preparations, was studied in laboratory conditions. Laboratory studies were conducted in accordance with the interstate standard and included the determination of the total number of microorganisms and common colimorphic bacteria. Studies have shown that THPS treatment allows for the complete presence of microorganisms in cooling water samples. Biocidal treatment was carried out with reduced concentrations of the reagent (up to 30 mg/l) in a wide pH range (from 6.5 to 9.0 units). Experiments have shown high efficacy of the drug in a wide pH range even when it is dosed in small doses and a decrease in the effectiveness of this biocide when using increased concentrations of cationic flocculants used at the stage of pretreatment of river water.

RELEVANCE. Steam methane reforming is the dominant method of hydrogen production. Its significant share in global CO₂ emissions highlights the importance of optimizing technological parameters to reduce environmental impact. The developed multi-component model of steam methane reforming in COMSOL Multiphysics is relevant not only due to its applicability for optimizing existing production facilities but also for its potential in developing new methods for utilizing associated petroleum gas. In the context of import substitution in the hydrogen energy sector, this model is also of interest, allowing for the calculation of technological parameters of industrial installations.

THE PURPOSE. The aim of the work is to develop and verify a multi-component model of steam methane reforming.

METHODS. The research methodology includes the use of experimental data from the literature and industrial indicators for integration into a multi-component model in COMSOL Multiphysics. This enables the modelling of complex chemical interactions under conditions characteristic of the industrial steam methane reforming process.

RESULTS. The developed multi-component model allows calculating key parameters of the steam methane reforming process, including the concentration of components (methane, hydrogen, carbon monoxide, and carbon dioxide) and temperature along the reactor. The model successfully describes the chemical interactions between components and takes into account the influence of operating conditions, such as temperature, pressure, and steam/gas ratio, on process efficiency. The model verification was carried out by comparing the modelling results with experimental data and indicators of real industrial processes. Their correspondence confirms the high degree of reliability and suitability of the model for practical application in engineering calculations and optimization of steam methane reforming processes.

CONCLUSION. The conclusions made based on the modelling can be used for further improvement of methane conversion technologies, contributing to their efficiency and environmental friendliness. There is also potential for using the model to calculate the stages of installations for the utilization of products from the processing of associated petroleum gas.

RELEVANCE. The authors research the potential energy, economic and environmental effects of using local heat recovery from wastewater generated in showers. At the moment in Russia, almost all household wastewater is disposed of in sewer networks without the beneficial use of the heat that they possess. It is important to determine the effect of implementing this method of heat recovery, to identify and analyze the problems that prevent this from being done.

THE PURPOSE. The purpose of the work is to determine the potential effect of using local heat recovery from wastewater generated in showers.

METHODS. Based on a verified mathematical model of the heat exchanger, the energy effect from the individual use of the shower room is determined. A number of assumptions are applied to the heat consumption structure of an individual building and, based on available data on the average annual heat consumption of residential buildings in Moscow, the economic and environmental effect of energy-saving measures is calculated.

RESULTS. Relative savings within the annual heat consumption of a building with a decentralized and centralized hot water supply system were 5,3% and 3,1%, respectively (64 and 37 GCal). Fuel economy amounted to: 9145 toe and 5227 toe for a building with a decentralized and centralized hot water supply system, respectively (14,5 and 8,5 thousand tons of CO₂-eq). The payback period for energy-saving measures for the case of a decentralized hot water system based on an instantaneous electric water heater was 1,5 years.

CONCLUSION. Local waste heat recovery makes it possible to obtain a significant energy and environmental effect within any locality, but at the moment there are no measures to support consumers implementing energy-saving measures. Currently, this method of heat recovery is of interest only to those consumers whose source of thermal energy for the needs of hot water supply is electricity.

The PURPOSE of the work is to determine the mass-flow characteristics of working substances and energy indicators of an installation based on a CO₂ cycle with a two-stage pressure increase (Allam cycle) during oxygen combustion of methanol.

METHODS. A research methodology is presented in which the mass-flow characteristics of working substances are determined based on the reactions of combustion and synthesis of methanol and electrolysis of water. These reactions are basic for ensuring operational processes in the installation. The method is based on the molar ratios of substances participating in reactions under stoichiometric conditions. Using the thermodynamic parameters of the cycle being implemented and at a given installation power, the consumption of the working fluid, the share of carbon dioxide renewal in the cycle, the amount of methanol produced in the synthesis unit, the amount of fresh methanol, the amount of hydrogen produced in the water electrolysis unit and the amount of oxygen are determined, necessary to ensure fuel combustion processes. At the same time, the amount of commercial hydrogen is determined. Electricity consumption for own needs is determined using regulatory methods and data from equipment manufacturers.

RESULTS. The article shows that with similar values of thermal efficiency of CO₂ cycles based on oxygen combustion of methane and methanol, the amount of carbon dioxide removed from the cycle for disposal is 11% less. It has been shown that a CO₂ cycle operating on methanol is capable of producing commercial hydrogen simultaneously with electricity generation. The specific electricity consumption for hydrogen production is 22% less than for its production without combination with the CO₂ cycle.