The article presents the results of research on modeling the DU-06-W-200 airfoil used in wind power plants with a vertical axis in the Ansys Fluent system, evaluating compatibility with experimental data and determining the optimal angle of attack. The DU-06-W-200 airfoil was simulated with angles of attack ranging from –15° to +15°, boundary conditions and input flow rate being of 15 m/s, operating temperature – of 23 °C, operating pressure – of 1·10⁵ Pa, air flow rate – of 1.23 kg/m³ (airfoil chord length is of 1 m, dynamic viscosity of the air flow is 1.7894·10^–5 kg/(m·s) and the type of turbulent models is SST k – omega (k – ω), k – epsilon (k – ε), whereas Reynolds number is 1.05·10⁶). A two-dimensional geometry domain and a grid profile for the DU-06-W-200 airfoil have been created, with the number of nodes in the grid 37495 and the number of elements 36790. It was also found that the drag coefficients (C_d) SST k – omega (k – ω) for the turbulence model were equal to 0.1734, 0.0721, 0.0311, 0.0204, 0.0351, 0.0782, 0.1712, k – epsilon (k – ε) for the turbulence model were equal to 0.2065, 0.0789, 0.0318, 0.0212, 0.0359, 0.0787, 0.2019, lift coefficients (C_l) SST k – omega (k – ω) for the turbulence model were  –0.9169, –0.9169, –0.9239, –0.5394, 0.0842, 0.7416, 1.3134, 1.1229, k – epsilon (k – ε) for the turbulent model was –0.9278, –0.8674, –0.5336, 0.0848, 0. 0359, 0.0787, 0.2019 at angles of attack of the DU-06-W-200 airfoil equal to –15°, –10^o, –5°, 0°, 5°, 10°, 15°, respectively. In assessing the compatibility of the model and the experimental results of the DU-06-W-200 airfoil, the conformity criterion χ², root mean square error (RMSE), coefficient of determination (R²), and average bias error (ABE) were used. Based on the results of a study of the dependence of the ratio of the drag and lift coefficients on changes in the angle of attack, carried out using the SST k – omega (k – ω) and k – epsilon (k – ε) turbulence models, it has been found that the maximum value of the ratio of the drag and lift coefficients is 21 at the optimal angle attack inclination equal to 5°.

A technique is proposed for the formation of emergency components of current and voltage of a power transmission line by a computational experiment in the MATLAB-Simulink dynamic simulating system (DSS) in order to use them as input information signals of additional stages of microprocessor protections with increased sensitivity. The emergency components of current and voltage are determined using orthogonal components. The emergency component of the short-circuit current is defined as the difference between the vectors (sinusoids) of the main harmonic of the short-circuit current and the current of the previous mode, if the effective value of this difference exceeds some predetermined value. Similarly, the emergency component of the voltage is determined, taking into account the fact that in emergency mode, the voltage at the place of installation of protection does not increase, but decreases. A computer software package (CSP) has been developed in the MATLAB-Simulink DSS to study the functional properties of microprocessor protection using emergency components of currents and phase voltages of a power transmission line of 6(10)–35 kV. The results of the formation of emergency components by models of digital measuring bodies of current and voltage protection are presented, confirming the operability of the developed software package. A CSP has been developed for calculating emergency components of currents and voltages of a power transmission line of 6(10)–35 kV using orthogonal components based on a mathematical model of the power supply unit of the protected line. The results of calculations of emergency components are presented, confirming the operability of the developed software package; a comparison of the results of calculating emergency components obtained by modeling in the MATLAB-Simulink DSS and using a CSP based on a mathematical model is also carried out.

The results of research and analysis of electromagnetic and thermal processes taking place in an induction motor are presented. Information is presented on the creation of a design 

model of an auxiliary induction motor with various parameters according to the Goldberg method and the procedure for selecting the option with the best electromechanical characteristics is described. The main factors influencing the calculation methods, taking into account the aging rate, temperature and distribution of the temperature field, are determined, as well as the service life of the insulation. The research has made it possible to develop and apply 3D models of electromagnetic processes using special programs, interactively without describing complex vector equations of field theory, while using the ongoing thermal processes. The cumulative effect of temperature and humidity factors on the insulation service life under various influences of aggressive media has been determined as well. A comparison of the characteristics of the real induction motor (IM), the model IM and the one calculated according to the standard methodology made it possible to calculate the error taking into account the correction factor relative to the data used in the calculation methods of assessment, and to use this value in new calculation and modeling methods. The proposed 3D models of electromagnetic and thermal processes taking place in asynchronous motors make it possible to evaluate the efficiency of an electric machine; improve the design taking into account the criteria of electrical steel throughput and winding temperature; they also create prerequisites for more accurate forecasts when assessing the insulation residual life based on temperature fields.

One of the main types of maintenance of steel underground gas distribution pipelines is periodic instrument inspection. This inspection is a kind of operational control, which includes detection of defects of insulation coating and gas leaks by instrumental methods, without opening the pipeline. This simultaneously controls two different levels of failure of the gas pipeline’s serviceability, one of which fully preserves its operability, but creates the possibility of a chain of events threatening to cause a failure in the future (insulation defect), while the other level of failure is, in fact, the case when the failure has already occurred (loss of tightness of the gas pipeline), but before the examination was not detected. All underground gas distribution pipelines are subjected to an instrument inspection with a certain regulatory frequency. The identified damages are subject to mandatory elimination, the serviceability and operability of the gas pipeline are being restored. Thus, periodic instrument inspection is a key technical measure that ensures the management of the technical condition of steel underground gas distribution pipelines. It should be mentioned that the work carried out during the inspection and further repair of gas pipelines is the most extensive and labor-consuming of all those performed on the linear part of the gas distribution system. Accordingly, adequate planning in this area is very important from the point of view of both the reliability and safety of the gas distribution network and the economic and economic one. At the same time, it is quite difficult to ensure the required adequacy of operational control planning and maintenance of engineering facilities in practice, since the maintenance process itself combines regulated and unregulated components and has significant inertia of management. The present article is devoted to the issues of reasonable forecasting of the scope of work on the instrument inspection of steel underground gas pipelines, taking into account a specially identified complex organizational and logistical factor reflecting the influence of existing production practices and management approaches in the field of gas distribution. The forecast is based on the currently relevant time series analysis methods.

The patterns of formation and development of defects in critical metal parts and elements of mechanical engineering, including power plants and heat engines of various classes, have been studied. The issues of dynamic processes of development of micro- and nanojointing structures of a fractal type from stress points in the solid material/metal of the internal chamber with the working substance of energy devices under conditions of different modes of their functioning are considered. At the same time, regularity, determinism and stochasticity can be realized according to various well-known scenarios, which is illustrated by the example of a number of modes. The possibility of dislocation development and reversibility of such processes, such as the formation of inhomogeneities and cracks, is also discussed. The modifications and development of the 3D fractured structure in the material are analyzed using simple analytical relations with the corresponding topological mappings inside the material with the emergence of fractal objects on the surface of the chamber. Although the analysis carried out is a model in the general formulation with known representation algorithms, nevertheless it is based on relevant physical principles and has obvious practical significance in terms of determining trends and directions for assessing the reliability and durability of such installations. All this makes it possible to qualitatively assess the trend in the development of instabilities and defects, which can eventually lead to the destruction of the solid-state working chamber of various power plants. The availability of a reliable database of their characteristics and operating modes of the working substance in real conditions with numerical parameters should allow, within the framework of the considered concepts, to fulfil predictive modeling and prediction of the durability of safe and stable operation of such devices and control their modes, taking into account appropriate metrological support.

The article discusses the current problems of transformation of existing district heating systems for the CIS countries within the framework of the development of trends in the integration of energy sectors, increasing the consumption of renewable energy resources, “decarbonizing” industry and digitalization of the economy. The experience of Western European countries in terms of the transition to “4th and 5th generation” district heating systems is considered. The technical aspects of the creation of hybrid control systems are analyzed, generalized structural technological schemes of hybrid district heating systems and the main measures, the implementation of which is necessary during their transition to the state of a new generation of district heating systems, are introduced. It is noted that the hybridity of the district heating system implies the presence of regenerative properties in terms of the production of energy carriers for use in adjacent systems, in particular hydrogen. In turn, the flexibility of the district heating system is largely realized via the development of accumulative properties, which leads to the invariance of the use of available energy storage technologies. It is argued that, despite the constantly decreasing costs of creating and operating an electric power storage system, thermal energy storage systems remain a priority in heat supply, especially when using renewable energy sources. The issue of using electricity in district heating systems as an excess resource of integrated energy systems within the framework of equalizing the daily and seasonal schedule of energy consumption is also considered. Also, a diagram is presented reflecting the technical solutions in terms of the equipment used to implement the “electricity – heat” technology. The problem of management of heat supply systems of a new generation is discussed. It is indicated that in order to ensure the required maneuverable properties of heat supply systems, it is necessary to develop and apply new methods of planning and managing heat supply systems, excluding a single-purpose approach in the organization of hybrid systems, which manifests a synergistic effect with new possibilities for finding optimal solutions aimed at reducing fuel consumption. The need to create an intersystem information space, which would include the creation of intelligent process control systems based on the analysis of large amounts of data, is demonstrated. It is noted that the main goal of operational management of hybrid thermal networks is to achieve a dynamic balance between the required value of the thermal load of consumers, the production of thermal energy and the volume of accumulation. The use of hybrid systems in heat supply makes it possible to solve the multifunctional task of increasing the reliability of energy supply and the stability of the functioning of the energy system, which is primarily achieved by solving the problem of balancing production and energy consumption capacities from the point of alignment of generation and energy consumption schedules. A separate consideration of the prospects for the use of hybrid district heating systems in the conditions of the Republic of Belarus is highlighted. The need for additional research to adapt known and develop new technical solutions within the framework of the transition of district heating systems to a new quality is shown.