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V. N. Romaniuk, A. M. Niyakovskii
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-259-274

Abstract:
Having proven its effectiveness in finding the best options for energy supply and energy consumption the exergetic method of thermodynamic analysis of complex heat and power systems has been widely recognized in recent years. However, its application is hindered by the lack of appropriate scientific and methodological heat technology support, especially if their application involves not only transformation of energy, but also transformation of substances. Heat treatment of concrete and reinforced concrete products belongs to such technologies. This article presents new scientific results related to the development of exergetic balances of the processes of preparation of concrete mixture in a mixer and heat treatment of a concrete product in a heat-technological installation. For each of these cases, the analysis of exergetic flows was carried out, the structure of the exergy of the concrete mixture and the hardening concrete was determined. Based on the analysis of the literature data on the chemical composition of cement clinkers, cements, and hydration products, new dependences have been proposed for calculating the exergy of the concrete mixture flow and the exergy of concrete under its heat treatment, including all their components, viz. thermomechanical, reaction, and concentration constituents. Absolute energy indicators have been developed. The calculation of the mentioned values was performed on a specific example with the use of the developed scientific and methodological support. In the second part of this paper, the results of the study related to the determination of relative exergetic indicators that allow evaluating the energy efficiency of the processes of heat treatment of concrete products in heat technology installations will be published. The results obtained in this paper can be used for the selection of energy-saving modes of heat-technological equipment intended for industrial heat treatment of concrete products.
F. A. Romaniuk, Yu. V. Rumiantsev, V. Yu. Rumiantsev, I. V. Novash
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-191-201

Abstract:
The methods used in the microprocessor protection of electrical equipment for forming orthogonal components of input currents ensure their reliable isolation after changing the mode followed by one or more periods of the fundamental frequency. This is due to the inertia of the functional elements, in particular, digital frequency filters, as well as the saturation of the steel magnetic cores of current transformers. To increase the speed of the selection of orthogonal components of the input currents, it is proposed to form them as equivalent ones in terms of the cosine and sine components obtained using digital Fourier filters by multiplying by the resulting coefficient. The method that has been developed for determining the specified coefficient provides compensation for the delay caused by the inertia of digital filters, as well as the saturation of the steel of magnetic cores of current transformers. The proposed method of forming orthogonal components is highly effective in the modes of strong saturation of the magnetic core with a complex input action in the presence of an aperiodic component with a large damping time constant. The evaluation of the efficiency of the proposed method was performed using a complex digital model implemented in the dynamic modeling environment MatLab-Simulink. As a result of the performed studies, it was found that in the absence of saturation of the magnetic core of current transformers, as well as in the presence of a small and medium degree of saturation, the proposed method for forming equivalent orthogonal components of input currents has dynamic properties close to the ones of those that had been previously proposed. With a strong saturation of the magnetic core of current transformers, the speed of obtaining reliable values of these components is increased by 1.5–2 times.
Й. Покорный, , T. Kriz, J. Janousek
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-219-227

Abstract:
The article presents a detection system with spider web coil-based wireless charging. Commonly available metal detectors are sold as handheld systems, which enable only progressive, lengthy, time-consuming search. Importantly, a part of the investigated area can thus be easily missed, and the probability that a metal object will not be found increases substantially. This problem, however, is eliminable via the automatic position tracking mode embedded in the solution obtained through our research. The proposed system facilitates using the spider web coil simultaneously for wireless charging and metal detection by pulse induction. The topology of the detector can emit variable pulse lengths, thus allowing the device to detect more types of metal and to adapt itself to the permeability of the soil. The coil has a branch in a relevant part of the winding to reduce undesirable electromagnetic interference during the charging. On the transmitting side of the topology, impedance matching is included to maintain the maximum spatial gap variability. By changing the position of the receiving side, the output voltage changes; therefore, a high efficiency DC/DC converter is employed. The individual battery cells demonstrate different internal resistances, requiring us to apply a new method to balance the cells voltage. The system can be utilized on self-guided vehicles or drones; advantageously, a GPS resending the coordinates to a mesh radio allows for accurate positioning. With the mesh topology, potential cooperation between the multiple systems is possible. The setup utilizes the same coil for wireless power transfer and detection.
V. V. Ivashechkin, V. I. Krytskaya, V. N. Anufriev, O. A. Avrutin
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-275-286

Abstract:
The reducing in the pressure characteristic of the submersible pump during operation occurs as a result of the combined action of a number of reasons. Pumping equipment wears out due to waterjet destruction of flow channels. The characteristics of submersible pumps are captured at the factory on special stands. At large group groundwater intakes, wells are equipped with an automated control system that allows testing the pump at the workplace and promptly making a decision on its replacement if the pressure characteristic is unacceptably reduced. The actual pressure characteristic of the pump H н = f (Q) can be plotted directly in the well with a sufficient degree of accuracy. To determine the degree of wear of the pump, its pressure characteristics are compared before installation and at the time of taking readings. The article describes a well strapping scheme for measuring the specific flow rate and pressure characteristics of a submersible pump. The purpose of the study is to derive a dependency for constructing the flow-pressure characteristics of a submersible pump at its workplace and to develop a method for accounting for its wear during operation, which allows predicting a decrease in well productivity over time. An expression is proposed to describe the characteristics of the pump at any time, calculated from its installation in the well. The analysis of the reducing in the pressure characteristics of pumps produced by various manufacturers in the wells of the existing water intake of underground water is presented. It is confirmed that the intensity of the pressure reduction depends on the duration of the pump operation in a given well, the material of the pump impellers and the sand content in the pumped water.
, Г. Л. Зыков, V. A. Potachits, V. K. Kuleshov
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-250-258

Abstract:
Solar radiation is an environmentally friendly and affordable energy source with high release of energy. The use of a photovoltaic thermoelectric battery makes it possible to increase the efficiency of converting solar and thermal radiation into electrical energy, both on serene and cloudy days. An original battery structure with photovoltaic and thermoelectric converters is proposed. The 3D model of the proposed photovoltaic thermoelectric battery was realized in the COMSOL Multiphysics software environment with the use of a heat transfer module. The simulation was performed for the geographical coordinates of Minsk and taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the concentrated AM1.5 solar spectrum, the maximum value of which being varied from 1 to 500 kW/m2. The dependences of the maximum temperature values of the photovoltaic thermoelectric battery and the thermoelectric converters as well as temperature gradient patterns in the thermoelectric converters have been calculated. The dependences of the maximum temperature gradient values inside the thermoelectric converters on the solar power density are obtained. The graphs of the temperature gradients inside the thermoelectric converters of the photovoltaic thermoelectric battery by concentrated solar radiation versus the time of day in the middle of July and January are provided. It is shown that the output voltage increases up to the maximum values of 635 and 780 mV, respectively, in January and in July were achieved due to the temperature stabilization of the back side of the external electrodes of the proposed device
В. П. Счастный, A. I. Zhukouski
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-239-249

Abstract:
The efficiency of an enterprise’s power supply system depends on the quality of electricity and the losses of the latter in electrical networks; both being largely determined by the modes of voltage control and reactive power compensation. In practice, the problems of voltage control and reactive power compensation in power supply systems of industrial enterprises, including electric networks with a voltage of up to 1 kV, as well as 6, 10 kV and higher, are often solved separately. It triggers an irrational use of existing voltage control devices, underutilization of the installed capacity of compensating devices, and affects the voltage control in the electrical networks of the power supply organization. Since voltage management and compensation modes of reactive power are inseparable, they can be correctly determined only with the use of an integrated approach based on technical and economic criteria and taking into account technical requirements and local conditions. This article analyzes the mutual influence of voltage control and reactive power compensation modes in the electrical networks of industrial enterprises from the point of view of ensuring the quality of electricity and minimizing load power losses. The method and results of calculations (on the example of a specific industrial facility) for determining voltage deviations and losses in the electrical network as well as for selecting parameters for voltage control and reactive power compensation are presented. Due to the close relationship of these modes that affect all voltage levels, the effectiveness of measures cannot be ensured without the use of multifunctional devices for controlling the equipment of transformer substations.
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-228-238

Abstract:
The increase in the levels of short-circuit currents in the power system of the Republic of Belarus requires the study of the parameters of the electrodynamic stability of the main structural elements of electrical installations with flexible conductors. In case of a short circuit in the network, currents tenfold exceeding the rated one hundreds of times can flow through the current-carrying part of the device. When the magnetic fields formed by these currents interact, significant electromagnetic forces arise, which have a destructive effect both on the current-carrying parts themselves and on the structural elements of electrical installations, viz. support insulators, switching devices, measuring equipment. The movement of the wires in a short-circuit mode leads to the appearance of significant dynamic loads in them, which, in turn, are transmitted to the portals, support insulators and electrical devices. A topical problem is the occurrence of unacceptable mechanical forces in the main structural elements that can cause their destruction. Thus, the analysis of the physical and mechanical parameters and geometric dimensions of the flexible busbar of switchgear shows that a violation of the condition of electrodynamic resistance to tension is unlikely due to the high mechanical strength of the large-section steel-aluminum wires used. At the same time, span-limiting portals, support insulators and other electrical devices have significantly lower permissible bending loads. When exposed to dynamic forces, the conductors bend and transfer the load to the structural elements which have certain elasticity. Thus, a reliable determination of dynamic loads, taking into account the current-carrying parts acting on the supporting structures, is possible only if a dynamic task is set. The article describes the methods of mathematical modeling and computational experiment for analyzing the parameters of the electro-dynamic stability of the main structural elements which are determined using coefficients that depend on the natural frequencies of oscillations and the nature of changes in dynamic forces over time. To solve these problems, mathematical models are compiled and boundary value problems are formulated for calculating the electrodynamic stability of structural elements, taking into account the possible coincidence of the frequencies of natural and forced oscillations of structural elements taking into account the probable coincidence of the frequencies of forced and natural vibrations of structural elements.
I. V. Zhezhelenko, V. E. Kryvonosov, S. V. Vasilenko
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-3-202-218

Abstract:
At industrial enterprises, seaports, ships, more than 80 % of all electrical engineering equipment is asynchronous motors. In a number of cases, asynchronous motors operate with a sharply variable load, in an aggressive environment; herewith they receive power from the network with deviations of the power quality indicators from the normative ones, which causes their high damageability. Turn circuits in the stator windings account for about 40 % of cases of damage to the insulation of the asynchronous motors windings. Untimely detection of the initial moment of the appearance of defects in the asynchronous motors or disruption of the operating modes of the supply network and current circuits result in emergency situations of the electrical complex, equipment downtime and damage. The article discusses the issues of diagnostics of non-full-phase modes of current circuits, mains voltages and turn circuits in the stator windings of the asynchronous motors that receiving power from the networks in conditions of voltage asymmetry. The analysis of the vector diagrams of currents, voltages and additional phase angles of the phase currents displacement arising from the asymmetry of the mains voltages and turn circuits in the stator windings has been fulfilled. The results obtained made it possible to formulate criteria for identifying the initial moment of the turn circuit and two-phase modes, both in the network and in current circuits, in stationary modes. A method for non-destructive testing of the asynchronous motors state as well as a device for its implementation has been developed. The method is based on comparing the vectors of the measured phase currents of the asynchronous motors with their calculated values. The article presents the results of modeling the change in the vectors of phase currents from the number of closed turns in the winding of the asynchronous motors. The power series of asynchronous motors was established, for which the sensitivity of detecting the initial moment of the turn-to-turn short circuit is maximum. Analytical results of the dependence of the sensitivity coefficient for turn-to-turn short circuit on the absolute increment of the modules of phase currents and the corresponding phase angles have been obtained.
Yu. V. Burtyl, M. G. Salodkaya, Ya. N. Kovalev
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-216-223

Abstract:
The design of road surfaces involves application of a sophisticated algorithm system based on mathematical calculations and engineering solutions, with the calculation of evaluation criteria. It is precisely the observance of the standardized requirements in terms of design criteria that makes it possible to consider the design of the pavement as reliable, and the road as safe and convenient for traffic during the specified service life. When calculating the strength, based on the predicted traffic intensity and the composition of the traffic flow, calculations are carried out according to the main criteria: admissible elastic deflection, shear in layers of non-reinforced materials and in asphalt concrete, as well as the ultimate tensile stresses in cast-in-situ materials with the specified reliability level. However, in the accepted concepts for calculating the strength and reliability of road pavements, only the force effect is directly taken into account. To take into account environmental factors, it is necessary to develop a comprehensive indicator of the resulting impact of all factors. The paper presents a complex of factors influencing on traffic safety, road deformations and irregularities the height of unevenness, in particular, an increase in the dynamic impact on the road and the amplitude of vibration of a car wheel on a road with an uneven surface (when detached from the road surface), the coincidence of the vibration frequency of the car with the natural frequencies of vibration of the road surface, and as a consequence, on the behavioral features of driving. The arguments have been substantiated that the predictive models do not take into account a number of factors that have a significant impact on the formation of irreversible deformation in the layers of materials of road structures.
N. S. Sivtsev, V. V. Tarasov
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-259-267

Abstract:
In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.
V. A. Sednin, Т. В. Бубырь
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-248-258

Abstract:
A schematic and structural solution of regenerative-utilization heat use in centralized heat supply systems was previously proposed in order to increase the efficiency of operation of heating networks located in non-passable channels. The impossibility of creating a full-scale experimental setup covering the required range of factors and the area of their change, the complexity of a passive experiment on existing heating mains led to the need to develop a virtual model based on the ANSYS sofware package. A six-factor experiment has been carried out on this virtual model. Regression equations have been obtained to determine the pressure required to provide air purging of the channel, as well as heat exchange with pipelines of direct and return network water located in the channel, and heat exchange with soil around the channel. In addition, a regression relationship has been derived to find the integral heat flux from the listed washed surfaces to the air flow. The transition from dimensionless to natural factors has been made in the paper. The most significant factors are identified with the help of Pareto cards. The obtained dependencies have been verified in Part 1 of the paper. The adequacy of the obtained regression equations has been determined using standard statistical estimation methods based on the calculated values of the Fisher’s, Student’s and other criteria. The response surfaces are presented and analyzed using two dimensional sections for a number of factor values at fixed values of one and a change in two most characteristic, physically significant for a given response function. They have been validated on the basis of the analysis of regression dependencies. The obtained regression equations cover almost the entire range of possible diameters of heating mains, which makes it possible to use them in the development of energy-saving projects.
E. N. Polonina, , B. M. Khroustalev, E. A. Sadovskaya, N. A. Budrevich
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-189-194

Abstract:
The most common and reliable material without which modern construction is indispensable is concrete. The development of construction production is pushing for new solutions to improve the quality of concrete mix and concrete. The most demanded and significant indicators of a concrete mixture are the compressive strength and mobility of the concrete mixture. Every year, the volume of research on nanomaterials as modifying components of concrete is significantly increasing, and the results indicate the prospects for their use. Nanoparticles with a large specific surface are distinguished by chemical activity, can accelerate hydration and increase strength characteristics due to nucleation and subsequent formation of C–S–H and compaction of the material microstructure. Sol of nanosilica, which can be used instead of microsilica from industrial enterprises, and carbon nanomaterial have a wide reproduction base. This paper presents studies of these types of nanomaterials and the results of their application in cement concrete. Studies have shown that the effect is also observed with the introduction of an additive containing only one type of nanoparticles. The dependence of the obtained characteristics of cement concretes on the content of these nanomaterials has been established. It has been found that the best results were obtained with an additive in which the above-mentioned nanomaterials were used together. Compressive strength of heavy concrete samples, improved by the complex nanodispersed system, was 78.7 MPa, which exceeds the strength of the sample containing the CNT additive in a pair with a super-plasticizer by 37 %. The paper proposes the mechanism for action of the presented complex additive.
S. N. Kovshar, P. V. Ryabchikov, S. V. Gushchin
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-207-215

Abstract:
The paper describes a technique for assessing the thermally stressed state of a concrete massif of a foundation slab made of a self-compacting concrete mixture. The proposed method consists in a preliminary calculation of temperature fields in hardening concrete. The objects of research have been self-compacting concrete mix and structural concrete in the structure mass. The choice of materials for the preparation of a concrete mixture is given and substantiated. The composition of self-compacting concrete has been used to assess the thermally stressed state. A binder with a reduced exotherm has been used in order to reduce the self-heating of concrete. Studies have been carried out to assess the specific heat release of the recommended cement depending on the initial water-cement ratio. The effect of a chemical additive on the rate and magnitude of the specific heat release of cement has been studied. The paper presents the main theoretical provisions and an algorithm for calculating the thermal stress state of a concrete massif. The finite difference method has been used to calculate the expected temperatures and their distribution in the structure mass, and the temperature stresses in the sections of the concrete mass have been calculated to assess the thermally stressed state. The performed calculations of the temperature fields have made it possible to estimate the maximum possible temperatures and temperature differences over the sections of the concrete massif depending on the initial temperature of the concrete mixture and the average daily temperature of the outside air. Analysis of the temperature distribution has revealed the most dangerous sections of the concrete mass. An assessment of the thermal stress state of the concrete mass has been made on the basis of the results pertaining to calculation of temperature fields. The calculation of temperature stresses in the most dangerous sections of the concrete massif has been performed. It is shown that the calculated value of the temperature stress can serve as a characteristic of the thermally stressed state of the concrete mass. The formation of temperature cracks in a concrete mass is possible when the calculated value of the temperature stress exceeds the actual tensile strength of concrete. Comparison of the calculated and actual values of temperatures in the sections of the foundation slab has made it possible to conclude that the calculations of the temperature fields and, as a consequence, possible temperature deformations are correct.
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-268-274

Abstract:
The new types of elastic devices – staple-shape plate spring and leaf spring - have been developed at the Kyiv National University of Construction and Architecture. The staple-shape plate spring is an elastic plate where the ends are deflected from its middle part in the same direction and are made in the form of consoles equipped with hinge attachments. The middle part of the plate as a parallel to the line of the load action is designed with variable length section. In each section, the axis, relative to which the moment of the section inertia is a maximum, is perpendicular to the spring bending plane, designed as the equal resistance beam. This article substantiates the feasibility of using a staple-shape plate spring to improve the elastic suspension of truck cabs. The recommendations for choosing the most promising mass production directions, as well as the engineering calculation methods of such springs, have been developed. Objects of the study are devices intended for machines and their components dynamic loads shock absorption, differing in having a bracket shape and being a subject to bending in the plane of the highest rigidity of their cross sections, as well as shock absorbers using these springs, in particular KamAZ cabs suspension. This research implementation allows significantly reducing the metal consumption and elastic devices manufacture complexity, as well as can be useful in the design and operation of elastic car suspensions.Keywords: elastic device, staple-shaped plate spring, leaf spring, elastic suspension
V. N. Romaniuk, A. M. Niyakovskii, A. N. Chichko, Yu. V. Yatskevich
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-195-206

Abstract:
Production of concrete and reinforced concrete products in the conditions of the Republic of Belarus and in the countries with similar climatic conditions requires heat treatment in heat-technological installations in order to achieve the desired strength of the products at the appointed time, which consumes a great amount of thermal energy. In this case, the purpose of equipment operating modes is associated with a number of difficulties when it comes to new products of complex spatial configuration and structure. The optimality criteria of such modes are, as a rule, the duration and temperature limits of processing, providing the required strength with minimal energy consumption. In the conditions of serial production in the case of structurally simple objects, the assignment of heat treatment modes is carried out empirically. As the analysis shows, the modes obtained in this way do not meet the above criteria, especially from the standpoint of energy saving. The paper, using a mathematical model previously developed by the authors, proposes dependencies for calculating the optimal modes of heat treatment of concrete products that are distinguished by a complex spatial shape and multi-component structure. The method is based on three-dimensional transfer equations, taking into account internal sources of heat release due to the ongoing hydration reaction of the active components of the cement clinker, and the boundary conditions corresponding to the structure of the processed product, as well as the type of heat technology device for accelerated hydration. Equations are proposed for calculating the amount of heat energy supplied to the processed product providing a given strength at a specified time. On the example of a manufactured industrial concrete product and for the conditions of an actually used device for accelerated hydration, a comparison has been made between two limiting modes of heat treatment: with isothermal exposure and in its absence. As a result of the performed calculations, the dependences of energy consumption, temperature fields and the degree of hydration in the product for both modes have been obtained and an energy-saving mode of heat treatment corresponding to the case under consideration has been developed. It is shown that the used numerical method allows to solve problems of this type and to achieve thermal energy savings.
D. V. Kapskiy, E. N. Kot, S. V. Bogdanovich, A. G. Rybinskiy, K. Ibrayev
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-224-233

Abstract:
Road traffic accidents of vehicles with a rolling stock of railways lead to the most serious consequences. Many level crossings are places of long delays of vehicles both before and after the traffic. In this case and in many others, the intersections of highways with railways sharply limit the capacity of the highway. Level crossings require the utmost attention of the traffic organization, since they must include not only devices for the movement of cars, but also pedestrian and sidings. Despite the fact that the problem of road traffic accidents at level crossings is not new, research and analysis of statistics in this area continues around the world. The paper considers the level crossings on the Republican highways of the Republic of Kazakhstan. Research has been carried out on ways to improve traffic safety at such crossings. The situation at the level crossings of the roads of Republican significance, as well as possible restrictions and regulatory requirements, have been studied in the paper. The paper presents results of a detailed collection of data at the facilities, which will serve as the basis for the development of a detailed program for improving the regulatory and technical base of the road sector in Kazakhstan to improve the safety of road transport infrastructure, taking into account existing standards. Recommendations are given for the implementation and generalization of advanced international experience in organizing road traffic at railway crossings, which will contribute to the adaptation of the Republic of Kazakhstan in the context of the development of transport and communications.
V. N. Sukhodoev
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-234-242

Abstract:
The problem of damping the noise on the track, arising from the movement of the train, is solved sufficiently but it is simple, if the rail with spacers is laid inside the longitudinally located band sleeper-mechanism. The result is a layered rail thread, consisting of belts: a rail tape with elastic spacers on three sides, a tie-mechanism tape and a ballast layer. The unity of the layers is carried out due to their own mass. This is the static track without external load. Rail compression is an effective property of rail tracks. It is formed in the sleeper mechanism under the influence of vertical forces with displacements and their horizontal derivatives. When loading the track, the compression is carried out repeatedly with subsequent unloading.n this case, each previous changes in the conditions in work of the track are taken into account in the subsequent cycle of loading and unloading. A rail track with a rail compression is a kind of self-adapting linear system, which is necessary with frequent changes in load and operating conditions for silent performance of a functional purpose. The specificity of this path is that the movement of the wheel creates rail vibration and noise, which are immediately damped by compression with damping. The balance between the occurrence of noise and its suppression is achieved by the ratio of the lengths of half-sleeper shoulders as a lever. The condition for the appearance of a shift of the compression forces in the direction from vertical shoulder of the half-sleepers is the unequal settlements of the horizontal shoulder of the L-shaped half-sleepers and its eccentric loading. As a result of the research, the advantages of a rail track with rail compression have been revealed, which is a guarantor of the stability of the design parameters during long-term operation of the track. The cost of a rail track with rail reduction is halved as a result of steel savings, lower labor costs and operational needs.
, I. Grabarek, M. Kozłowski, A. Czerepicki
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-3-243-247

Abstract:
In recent years, intensive research on urban transport has been observed. The search is about finding such solutions that will enable, among others: increasing the importance of public transport, matching transport for the needs of people with reduced mobility, increasing capacity, reducing emissions, energy efficiency (technical and organizational dimension through the organization of transport on demand), increasing the vulnerability to recycling and remanufacturing. The paper presents the main concept and technical solutions of the innovative transport system – HMASSUT Prometheus (Hybrid Modular Autonomous System for Sustainable Urban Transport), which combines the concepts of personal rapid transport and an electric vehicle at the L4 autonomy level (according to the Society of Automotive Engineers classification). An assessment of the effectiveness of an innovative transport system using indicators used in road engineering is given in the paper. The concept of simulation and optimization of the transport network is presented together with the theory of cellular automata.
Ю. В. Мелешко
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-61-74

Abstract:
The article is devoted to the study of business models digitalization of the national industrial complex on the example of the Republic of Belarus. Considering the business models digitalization as an integral part of digital transformation, following the production and industrial services digitalization, the author substantiates the need, when choosing new digital technologies introduced into production, to take into account their impact on the transformation of business models. As a promising direction for improving the business models digitalization of the Belarusian industrial complex enterprises, the author highlighted the expansion of the functional use of digital platforms to attract additional resources and competencies of partners, establish direct contacts with consumers, obtain information about the state of the market and quickly exit to international markets. Taking this into account, as well as the potential risks of business models digitalization (risks of cyber attacks, risks of technological dependence, risks of supply shortages, risks of data redundancy, risks of losing critical skills, risks of monopolization, risks of economic security), the author proposed practical recommendations for the development of digitalization of enterprises of the national industrial complex of the Republic of Belarus.
В. В. Фаузер, Т. С. Лыткина, А. В. Смирнов, Г. Н. Фаузер, T. Kuzmitskaya
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-23-38

Abstract:
The general dynamics of the Russia population in its northern territories, and the Belarus Republic is presented; the demographic component role in population dynamics and their transformation in the late twentieth century and early twenty-first century is shown. Special attention is paid to the effectiveness of migration exchange between the Northern territories and the Russian regions, and the scale of migration losses is shown. It is noted that the Russian North is highly urbanized, surpassing both Russia and the Belarus Republic and most of the countries of the foreign North in this indicator. In terms of the urban locality number, small and medium-sized cities are the leaders, while the majority of the population lives in cities of more than 100 thousand people.
S. Kuregyan
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-15-22

Abstract:
The article considers topical issues of economic theory subject. It shows that economic theory subject changes along with changes in the system of social relations and productive forces. Currently economic theory subject also includes the study of digital (electronic) economy with its inherent features.
A. Prasniakova
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-93-102

Abstract:
The article reveals the stages of the formation of sectoral approach to assessing the level of industrial technology in accordance with international practice. The differences between the categories «technology intensity» and «innovativeness» are determined in accordance with the recommendations of the Organization for Economic Cooperation and Development and regulatory documents of the Republic of Belarus. A comparative assessment is carried out and a much lower intensity of R&D in the manufacturing industry of our country is shown in comparison with international data, which necessitates the intensification of scientific research in the framework of the innovation process. Identified promising types of economic activities that produce products new to the domestic and world markets. Innovative projects for the creation of new industries based on technologies of the V and VI techno-logical modes are presented. The directions and instruments of state innovation policy for 2021–2025 in the field of creating new and accelerating the development of existing high-tech sectors of the economy are proposed.
В. В. Богатырева, М. Ю. Бобрик, T. Serhiyevich
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-6-14

Abstract:
The article is devoted to the study of the evolution of labor relations in the Republic of Belarus. It was revealed that the dynamics of labor relations in the Republic of Belarus corresponds to global trends, ensuring the transition of our country to a new quality of economic growth. It is concluded that the positive effects for the national economy will be the higher, the more it is possible to introduce digital technologies and robotic systems in the real sector of the economy, as well as in the presence of an effective state system for reducing the level of structural unemployment generated by the further development of the digital economy.
Zhao Houcheng, B. A. Zhalezka, V. A. Siniauskaya
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-126-131

Abstract:
In this paper different aspects of used car market development in China are analyzed. Influence of epidemic on the Chinese used car market is considered. SWOT-analysis of the Chinese used car market is made. Weaknesses and threats of Chinese used car market functioning are identified, strengths and opportunities of this market are revealed: strong policy support; market scale will enlarge; remarkable concentration increase; brand used car important role; trading service platform establishment. The market features indicated that Chinese used car market is making the shift to one of the dominant positions in Chinese auto industry.
M. Stashevskaya
Экономическая наука сегодня; doi:10.21122//2309-6667-2021-13-132-139

Abstract:
The article contains a study of existing views on the economic content of big data. From among the views, within which the authors define big data, the descriptive-model, utility-digital and complex-technological approaches are formulated. Against the back- ground of the large-scale spread of digital technologies (machine learning, cloud computing, artificial intelligence, augmented and virtual reality, etc.), functioning thanks to big data, the study of their economic essence is becoming especially relevant. As a result, it was found that the basis of economic activity in the digital economy is big data. The definition of big data as a resource of the digital economy is proposed.
C. Ю. Солодовников
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-119-125

Abstract:
The article reveals the factors that determine the need to expand the Belarusian-Romanian technological cooperation in the context of the new industrialization of the two countries, namely: the change in the dynamics of foreign trade under the influence of the growing domestic demand of developing countries; reducing the share of intermediate goods and services in international trade; the growing impact of new and emerging technologies on world trade; the need for a new industrialization within the social paradigm Industry 4.0; an unprecedented degree of concentration in several countries of the most important raw materials required for the modern stage of industrialization; an unprecedented rise in global social inequality.
D. Mukha
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-75-84

Abstract:
The article is devoted to the study of the phenomenon of Industry 4.0, the impact of the fourth industrial revolution on the key aspects of the companies’ economic activity, including multinational corporations. It was revealed how Industry 4.0 affects the placement and organization of global value chains. It was established that Industry 4.0 technologies contribute to the transformation of existing and the emergence of new (digital) business models, thanks to which companies can achieve a significant reduction in their own costs, gain additional income and enter international markets. It shows how Industry 4.0 can influence investment decisions, change the global flows and directions of foreign direct investment. As a result of the research, conclusions are drawn about the role of Industry 4.0 in the transformation of the business environment, industries, markets, and economy as a whole.
A. Pastukhov
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-85-92

Abstract:
The article is devoted to the modernization of industrial complexes in the context of sustainable development. It presents the national and regional aspects of industrial based on eco-innovation and industrial symbiosis as the ensuring the regional and national economic security, and also a list of organizational and technological measures for the formation of databases and knowledge in the field of eco-technologies and resource conservation.
Н. Г. Лопатова
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-112-118

Abstract:
The article is devoted to the study of the risks caused by the digital transformation of the economy. The content of the most significant risks associated with the internal and external environment is disclosed. It is revealed that the range of risks associated with the digital transformation of the organization is not yet clearly defined. The necessity of systematic consideration and identification of digital risks arising in the context of digital transformation of the company is substantiated. In the article, the author proposes the structure and content of internal risks associated with the timeliness and feasibility of investments, organizational transformation and digital skills, integration and implementation of digital technologies, and others.
С. А. Бунько
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-103-111

Abstract:
The article is devoted to the analysis of the inclusion of the Republic of Belarus in the processes of achieving the goals of sustainable development adopted by the world community. Environmental marketing is seen as a tool to achieve sustainable development goals in the area of responsible consumption. The essence of environmental marketing at the level of organizations and at the state level is determined. Directions for the development of environmental marketing in the Republic of Belarus have been identified in order to reduce the volume of non-decomposable waste and waste that cannot be recycled, including due to improper collection.
V. Baynev, Bin Zhang
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-49-60

Abstract:
In the conditions of the formation of a technotronic economy, the competitiveness of economic systems is determined by the level of their technological development, which, in turn, depends on the state of the national industrial complex. In the article, based on the use of the European classifier of economic activities, a methodology for assessing the level of technological effectiveness of economic systems is developed and tested on the data of Belarus and China. It is shown that the Belarusian economy is in a state that can be characterized as "technological stagnation", at a time when China is demonstrating dynamic technical and technological progress. It is concluded that it is necessary to give the status of the main strategic priority to a purposeful increase in the technological level of the Belarusian economy.
А. И. Лученок
Экономическая наука сегодня; doi:10.21122/2309-6667-2021-13-39-48

Abstract:
The drawbacks of monetarist and fiscal definitions of the terms "finance", "financial system" and "financial policy" are revealed and the author's definitions of these concepts are theoretically s justified. The goal of financial policy is defined as ensuring sustainable balanced socio-economic development of the country based on economic incentives and harmonization of the economic interests of the main social macrogroups. One of the main objectives of financial policy is to ensure the financial stability of all sectors of the national economy (including the real one) while stimulating economic growth by supporting the domestic producer. The author's interpretation of the term "economic intermediaries" is given, which include economic agents that redistribute value added in their own interests to the detriment of the interests of the real sector of the economy.
D. V. Нansetski
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-4-11

Abstract:
An innovative project to create a prototype of a multifunctional mobile automated stringed robotic complex is announced. A distinctive feature of the project is the mobility in relocation and the maximum use of artificial intelligence to solve problems of ensuring the security of a protected object or territory.
А. А. Лобатый, A. Y. Bumai, S. S. Prohorovith
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-21-28

Abstract:
The problem of the stage-by-stage synthesis of the mathematical model of the autopilot of an unmanned aerial vehicle (UAV) is considered. At the first stage, an analytical synthesis of the control acceleration applied to the center of mass of the UAV is performed to form a specified trajectory of its flight. On the basis of the results received at the first stage, at the subsequent stages, the problem of synthesizing a mathematical model of the UAV autopilot is solved with the specified requirements for ensuring the stability and dynamic accuracy of UAV control. Under actual assumptions about the corresponding nature of changes in the trajectory parameters and variables that characterize the motion of the UAV in space, the use of a linear mathematical model of the evolution of the state vector of the UAV and its control system is substantiated. When synthesizing a mathematical model of the UAV autopilot, the method of modal control of the system was used for a specified mathematical model of the object. For a specified model of motion and aerodynamic characteristics of the UAV, the law of deviation of the control steering surface is analytically received, which depends on the parameters of the translational and rotational movement of the UAV. Computer simulation of the analytically received results of control synthesis for the specified characteristics of UAVs and specific using conditions was carried out, which clearly showed the efficiency and prospects of using this approach for the synthesis of control systems for UAVs of various purposes and design.
V. G. Mikhailov
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-29-37

Abstract:
Use of CAN BUS for data transmission in Real-Time mode with Simulink on control objects is considered (6-DoF a platform). It is revealed that software of CAN_ API.dll adapters, created in the Microsoft Visual Studio (MVS) does not work with TDM-GCC-64 Matlab/Simulink because of different approach in names of the dll functions according to the standard C ++ 11/17. Recompile by the developer of the adapter of its software (dll) in the TDM-GCC-64 environment under Windows is required. It is established that CAN BUS considerably reduces modeling speed by 4.5 times. The way of information compression and fall forward of exchange twice due to byte-by-byte entering of two float values in the data field is offered. Use of identical values of identifiers is applied to two cylinders 6-DoF of a platform and the subsequent their division in the program microcontrollers of cylinders. For implementation of a Real-Time mode in addition to compression it is offered to transfer data with the smaller frequency (quantization) by what a modeling clock period. It was considered that 6-DoF platforms reproduce frequency band to 10–12 Hz. The program of transfer/data exchange with Simulink on stand control devices with quantization is developed. Influence of parameter of quantization for the period of modeling is investigated. It is established that the Real-Time mode of modeling is provided in the range of parameters of quantization (chc=1/350–1/1000). Frequency of exchange with 6 cylinders at the same time corresponds to 230, 150 Hz.
U. A. Vishniakou, А. Х. Аль-Масри, S. K. Al-Haji
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-39-44

Abstract:
Качество молока оценивается рядом контрольных точек, в качестве которых приведены ряд показателей, таких как жирность, белок, лактоза, плотность и т. д. Для контроля качества молока распределенных молочных хозяйств предложено использовать технологию интернет вещей (ИВ). Представлена многоагентная модель сети ИВ и структура такой сети ИВ для контроля качества молока от различных хозяйств. Модель представлена множеством агентов: анализаторов молока, преобразователей, хранения показателей качества молока, их обработки, принятия решений, мониторинга показателей качества молока.Структура сети ИВ включает анализаторы молока, шлюзы-преобразователи, облачную платформу, мобильные устройства. В облачной платформе арендуется сервер, на котором расположены базы знаний и данных, специальное ПО (решатель) по обработке и принятию решений по качеству молока, сайт ферм. В базе данных сервера облачной структуры хранятся характеристики качества молока, в базе знаний – правила их обработки. Решатель выдает отклонения по текущим показателям качества молока от стандартов. Сайт служит для связи специалистов по контролю качества молока. Мониторинг характеристик качества молока реализуется с мобильных устройств специалистов, доступом к компонентам сайта.В качестве сети передачи информации с молочных ферм в облачную среду выбрана сеть 4-го поколения LTE с использованием технологии NB-IoT. Проведен обзор анализаторов молока как отечественных, так и зарубежных компаний. Представлен вариант решения по шлюзу для опроса анализаторов молока и передачи параметров в облачную инфраструктуру. Представлены облачные популярные платформы для построения сети ИВ.
D. A. Kechik, Yu. P. Aslamov, I. G. Davydov
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-53-61

Abstract:
Problem of estimation of variated frequency of components of polyharmonic signals has been arose. Three-dimensional time-frequency representation of signals is usually used to resolve this problem. But simple and reliable method of instantaneous frequency tracking is needed. Frequency tracking method based on estimation of shifts of peaks of spectrogram has been proposed in this paper. It is assumed that shift of spectral peaks of components of signal is proportional to variation of fundamental frequency. Logarithmic scaling of time-frequency representation is used to make spectral peaks equidistant. Temporal dependence of shift of spectral maximums is obtained using correlation of windowed spectrum at the first frame and spectrum of signal in the current window. Then obtained track is translated in linear scale. Proposed method does not estimate values of instantaneous frequency or central frequency of signal component but estimates its variation. Advantage of the method is that it can estimate frequency track even if range of frequency variation and its central value are known roughly or unknown at all. Multiple components do not interfere to estimate fundamental frequency variation. Reduction of bandwidth is recommended to increase accuracy of frequency track estimation, but analysis of time-frequency representation containing a few components is also possible. Dependency of performance of analysis of synthetic signals using the method on various signal to noise ratios under different conditions was estimated. Applicability of the method for vibrational diagnosing of rotary equipment was checked out using spectral interference method.
Ma J., V. Yu. Tsviatkou, V. K. Kanapelka
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-62-69

Abstract:
The aim of the work is to limit excessive thinning and increase the resistance to contour noise of skeletons resulted from arbitrary binary image shape while maintaining a high skeletonization rate. The skeleton is a set of thin lines, the relative position, the size and shape, which conveys information of size, shape and orientation in space of the corresponding homogeneous region of the image. To ensure resistance to contour noise, skeletonization algorithms are built on the basis of several steps. Zhang-Suen algorithm is widely known by high-quality skeletons and average performance, which disadvantages are the blurring of diagonal lines with a thickness of 2 pixels and the totally disappear patterns of 2x2 pixels. To overcome them, a mathematical model that compensates the Zhang-Suen algorithm has proposed in this paper, along with a producing mask and two logical conditions for evaluating its elements.
V. V. Legkostup, V. E. Markevich
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-12-20

Abstract:
This paper discusses the problem of determining a kinematics (in terms of transfer function, as far as possible) of parameters of the motion of an aircraft expressed in the curvilinear coordinate system and control accelerations expressed in a rectangular coordinate system. Examples of curvilinear coordinate systems using in practice can be polar, biangular, two-center bipolar, elliptic, parabolic cylindrical, spherical, ellipsoidal, coordinate systems. A technique for obtaining a kinematic link for the control problem of an unmanned aerial vehicle in the elliptic coordinate system was described. It allowed to obtain simpler view of the kinematic link which could provide navigation an aircraft along the hyperbola deriving from the time difference of arrival navigation system. It can. As a result, it is possible to reduce the number of the navigation radio beacons.
A. A. Zhuk, V. M. Buloichyk
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-45-52

Abstract:
Given article is devoted features of the decision of a problem of integer nonlinear programming, by means of developed neural network method and algorithm of nonlinear optimization of means «decision Search» tabular processor Microsoft Excel. In offered neural network method the task in view decision is made by means of a recurrent neural network (RNN) matrix architecture with m neurons in each line and n neurons in each column. All neurons such network are connected with each other by communications, and the signal from an exit neuron can move on its input. Neural network method is characterized by that on inputs mentioned RNN the entrance vector of values of parameters of optimized nonlinear criterion function of a problem of distribution of a non-uniform resource moves, calculation of values of weight factors connected among themselves neurons is carried out and signal RNN is formed. This signal by means of nonlinear function will be transformed to the discrete target signal characterizing values quasi-optimal of the decision of the mentioned problem which size changes from 0 to 1. The estimation of efficiency of the decision of a considered problem was carried out at its various values of an indicator of efficiency on the basis of developed imitating model RNN. As indicators of efficiency of application offered neural network method were used – an average relative error and time of the decision of a problem. The value received by means of algorithm of nonlinear optimization of means was accepted to the exact decision «decision Search» tabular processor Microsoft Excel. The analysis of the received results of the experimental researches, offered neural network method, has allowed to make the conclusion that in comparison with an existing method of nonlinear optimization of tabular processor Microsoft Excel use offered neural network method allows essentially (in 9,4 times) to lower time of the decision of a problem dimension 10 × 8 (m × n) and thus to provide accuracy of its decision not less than 99,8 %.
A. V. Petukhov
«System analysis and applied information science»; doi:10.21122/2309-4923-2021-1-71-75

Abstract:
The modern stage of development of CAD-systems is characterized by a significant expansion of the scope of their use. An interesting direction for improving CAD systems is their integration with CAM systems. One of the main tasks solved by CAM systems is the development of control programs for CNC machines. Many software developers for automation of design and technological preparation of production have already equipped their systems with appropriate modules. These circumstances pose an urgent task for higher educational institutions to introduce the study of integrated CAD/CAM systems into the educational process of training design engineers. In this case, the emphasis should be placed on the practical mastery of the skills of developing control programs using a 3D-model of the manufactured part. The stages of preparation for the implementation of the system are described, starting with the analysis of the market of necessary software products and ending with the adaptation of the licensed system to the conditions of use in the educational process of the university. A link is given to the description of the methodology used in the assessment of automated systems at the stage preceding the tender for their purchase. It is emphasized that the study of the possibility of using a CAD/CAM system in the preparation of design engineers was carried out by students during the course and diploma projects in the discipline “Automated systems for technological preparation of production”. The methodology for designing control programs used by students is given, and the results obtained are assessed.
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-178-186

Abstract:
Localizing safety systems are provided to contain radioactive substances in an accident and attenuate ionizing radiation at a modern nuclear power plant. Together with radioactive substances, hydrogen is also retained, which is formed during the decomposition of the primary coolant. The accumulation of hydrogen in the presence of oxygen from the atmosphere in the accident localization zone carries the danger of the formation of flammable and explosive concentrations of these components. Nuclear power plant (NPP) deigns with water-water energetic reactor (WWER) provides for a hydrogen removal system including passive catalytic hydrogen recombiners. The device capacity is confirmed experimentally under reference conditions (lean air-hydrogen mixture, pressure and temperature close to normal, no interference with gas exchange). Capacity is an important safety parameter. In the event of an accident, conditions inside the ealed enclosure of the localizing system of NPP with WWER can differ from the reference ones and affect the capacity. On the basis of calculations, the operation of recombiners with lack of oxygen and with hindered gas exchange has been investigated in the paper. The decrease in capacity with lack of oxygen reaches 50 %, which is mainly caused by an increase in underburning. Compared to the reference conditions, the effect is more pronounced in the event of an accident – 60–70 %. The hindered gas exchange is modeled by a decrease in the height of recombiner traction channel. This case can be reduced to the placement of the device in cramped conditions and the effect of the atmosphere speed inside the enclosure. Regardless of the hydrogen concentration, the operating characteristic of the device remains linear, with a two-fold decrease in height leads to a decrease in capacity by 20 %. The results can be used to substantiate the safety of NPPs with WWER and to review on the safety subtantiation of power units.
, K. S. Kupavykh
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-143-151

Abstract:
The paper analyzes the main techniques and technologies of oil fluid recovery in the context of energy consumption, significantly rising over the latest decade. It is recognized that the number of publications in the area of energy efficiency is growing steadily. Currently Russian oil and gas industry are facing the task of accelerating reduction of energy consumption while preserving, or even increasing, production rates. The task is complicated by the fact that the majority of deposits in Russia either have already entered (primarily, Volga-Ural region) or are now entering (West Siberia) their last stage of exploration, whereas new deposits in East Siberia are only being brought into production. Furthermore, a lot of new deposits, which provide for high recovery rates, are profitable a priori as at the first stage of exploration they do not need any artificial lift due to their free flow production without any oil well pumps. However, there is a significant share of new deposits with low-permeability reservoirs, which require either a system of reservoir pressure maintenance or periodic hydraulic fracturing. At the same time deposits at the late stages of exploration, apart from the use of pump units, systems of reservoir pressure maintenance and hydraulic fracturing, require regular repair and restoration, measures against salt and heavy oil sediments, mechanical impurities, flooding, etc., which all has a negative effect on well profitability. In order to solve these problems, the authors review existing methods and calculate specific energy consumption using various pump systems for hypothetical wells, varying in yield. According to the research results, it has been revealed that from the point of view of energy efficiency, it is desirable to equip low- and low-yield wells with sucker rod progressive cavity pump units, medium-yield ones – with electric progressive cavity pumps driven by permanent magnet motor, medium- and high-yield wells – with electric progressive cavity pumps or electric submersible pumps driven by permanent magnet motor, depending on the characteristics of the pumpedout oil fluid.
F. A. Romaniuk, Yu. V. Rumiantsev, V. Yu. Rumiantsev, I. V. Novash
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-95-108

Abstract:
The use of orthogonal components (OC) underlies the construction of measuring elements of modern protection and automation devices. In most microprocessor-based protections, the orthogonal component of the input signal is extracted using a discrete Fourier transform (DFT). The DFT disadvantages are its low speed, which is more than one period of the fundamental frequency, as well as the sensitivity to the free aperiodic component, which creates significant conversion errors depending on the time constant of its decay. Such a settling time of the true output signal is often unacceptable for the design of high-speed measuring devices. The paper proposes to form the OC of the equivalent signal according to the values of the cosine and sine OC of the fundamental harmonic, formed using the DFT by multiplying them by the resulting correction factor. The developed algorithm for the formation of orthogonal components of input signals in microprocessor protections is characterized by high speed in transient modes and it has wide functionality. So, the proposed digital device for forming the orthogonal components of an equivalent signal, in comparison with digital filter based on the DFT, has an increased operating speed both in the mode of occurrence of a short circuit and during the decay of the monitored signal, while maintaining the same characteristics as in the DFT in other modes. A block diagram of the proposed digital device for forming the OC of an equivalent signal has been developed, all blocks of which can be implemented on a microelectronic and microprocessor element base. A digital model of the specified device has been developed in the dynamic modeling system MatLab-Simulink in accordance with the structural diagram. As a result of the calculations, a significant (up to two times) increase in the performance of the proposed digital device for forming the OC in transient modes has been established in comparison with the shapers based on the DFT.
Y. V. Bladyko, E. G. Ponomarenko
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-109-120

Abstract:
A method is proposed for the mechanical calculation of flexible wires of substation in the presence of one tap to an electrical apparatus located in the middle of the span, taking into account its real location. The technique takes into account the presence of tension insulators strings, different heights of the suspension of wires. The loads on the conductor and tap depend on the climatic regime and take into account wind and icy conditions, as well as temperature changes. The transition to another climatic regime is performed by solving the equation of state, taking into account the coefficients of the horizontal and vertical load of the given and initial regimes. Formulas are given for calculating load factors that take into account weight, wind and ice cover loads on wires and insulator strings, as well as the slope of the span. They are calculated for each climatic mode based on the actual location of the tap to the electrical apparatus and the forces from it to the busbar. It is shown that the calculation results are in good agreement with the proposed method and the computer program. Formulas are given for calculating the sag and horizontal deviations of the wires when the tap is located in the middle of the span. A method is proposed for calculating the components of the forces on the busbar from the tap, taking into account its real location in substation. Formulas for calculating these components are given for different variants of the tap orientation. Knowledge of the values of the components of concentrated forces from the tap allows to increase the accuracy of calculating the sag and tension of the substation wires. Formulas are given for calculating the coefficients of increasing the sag, taking into account the components of the forces from the tap.
I. V. Oleksyuk
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-121-129

Abstract:
Preference is given to cable lines with cross-linked polyethylene insulation in electrical networks with a nominal voltage of 10 kV during reconstruction of existing and construction of new industrial enterprises. The standard service life of such cables is at least 30 years (subject to the conditions of storage, transportation, installation and operation), and the actual one is determined by the technical condition of the cable. The service life of a cable line depends on the state of its insulation, the aging of which occurs under the influence of several factors. Conventionally, all factors influencing one or another degree on the cable insulation resource can be divided into thermal, electromagnetic, climatic, mechanical and operational. The most significant reason for the insulation aging is high temperature, which accelerates the reaction of thermo-oxidative destruction, during which high-molecular polymer compounds decompose. In fact, cables are operated at temperatures below the long-term permissible values, and, therefore, the aging of the insulation is slower, and the actual service life will be longer than the standard. At present, condition of the insulation is monitored with the use of high voltage tests related to destructive testing methods. When designing and operating cable lines, it is necessary to estimate the duration of the actual service life under various operating conditions. In theory, there are several expressions for calculating the service life of a cable line when exposed to temperature, humidity, electric field and aggressive environments, but all of them are not applicable in practice due to the presence of a large number of coefficients whose values are unknown. The paper presents an analytical expression obtained for determining the service life of power electric cables, taking into account the aging of the insulation under the influence of temperature and electric field.
П. Г. Ласый, I. N. Meleshko
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-152-163

Abstract:
The mixed problem for the telegraph equation well-known in electrical engineering and electronics, provided that the line is free from distortions, is reduced to a similar problem for one-dimensional inhomogeneous wave equation. An effective way to solve this problem is based on the use of special functions – polylogarithms, which are complex power series with power coefficients, converging in the unit circle. The exact solution of the problem is expressed in integral form in terms of the imaginary part of the first-order polylogarithm on the unit circle, and the approximate one – in the form of a finite sum in terms of the real part of the dilogarithm and the imaginary part of the third-order polylogarithm. All the indicated parts of the polylogarithms are periodic functions that have polynomial expressions of the corresponding degrees on an interval of length in the period, which makes it possible to obtain a solution to the problem in elementary functions. In the paper, we study a mixed problem for the telegrapher’s equation which is well-known in applications. This problem of linear substitution of the desired function witha time-exponential coefficient is reduced to a similar problem for the Klein – Gordon equation. The solution of the latter can be found by dividing the variables in the form of a series of trigonometric functions of a line point with time-dependent coefficients. Such a solution is of little use for practical application, since it requires the calculation of a large number of coefficients-integrals and it is difficult to estimate the error of calculations. In the present paper, we propose another way to solve this problem, based on the use of special He-functions, which are complex power series of a certain type that converge in the unit circle. The exact solution of the problem is presented in integral form in terms of second-order He-functions on the unit circle. The approximate solution is expressed in the final form in terms of third-order He-functions. The paper also proposes a simple and effective estimate of the error of the approximate solution of the problem. It is linear in relation to the line splitting step with a time-exponential coefficient. An example of solving the problem for the Klein – Gordon equation in the way that has been developed is given, and the graphs of exact and approximate solutions are constructed.
D. I. Hvalin, O. H. Kensytskyi, К. А. Кобзарь
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-130-142

Abstract:
With the aid of mathematical and physical simulation the electromagnetic field distributions in the end zone of a powerful turbogenerator has been obtained. On the basis of the comparison of the axial component of the magnetic induction on the surface of the extreme package of the stator core of the large-scale physical and mathematical models with the data of the field experiment, conclusions are drawn about the reliability of the results obtained. The data of the simulation and the field experiment correspond to the same turbogenerator, which makes it possible to evaluate the correctness of the construction of the mathematical model. It is shown that physical modeling makes it possible to evaluate the regularities of the distribution of the electromagnetic field (without obtaining accurate quantitative indicators) and can be used for qualitative comparison of the effectiveness of various design solutions of the end zone of the stator. However, such models have not become widely used, since numerous studies are required to form meaningful and sufficiently detailed conclusions about the parameters and characteristics of the object, the design of the end zone of high-power generators is complex, and the calculation of three-dimensional models is time-consuming and even with modern computer technology is associated with a number of simplifying factors. In mathematical modeling, a sequential logical transition is applied from a simple model of the central part of the machine to a more complex model of the end zone using preliminary results, which makes it possible to obtain data on the distribution of the electromagnetic field in complex areas. With the help of specialized software, a model has been created that is quite flexible in terms of modifying individual components, characterized by accessibility, visibility and unlimited possibilities for experimentation, including predicting situations that have not previously occurred or can give unpredictable results.
A. V. Ovsyannik, V. P. Kliuchinski
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations, Volume 64; doi:10.21122/1029-7448-2021-64-2-164-177

Abstract:
The paper presents a thermodynamic analysis of secondary overheating in turbo-expander plants on low-boiling working fluids. The possibility of optimizing the parameters of the working fluid in a secondary stem superheater has been studied. The research was carried out for two typical turbo-expander cycles: with a heat exchanger at the outlet of the turbo-expander, intended for cooling an overheated low-boiling working fluid, and without a heat exchanger. Cycles in T–s coordinates were constructed for the studied schemes. The influence of pressure and temperature in the intermediate superheater on the exergetic efficiency of the turbo-expander unit was studied. Thus, the dependences of the exergetic efficiency and losses on the elements of the turbo-expander cycle are obtained when the temperature of the working fluid changes and pressure of the working fluid not changes in the intermediate superheater, and when the pressure changes and the temperature does not change. As a low-boiling working fluid, the ozone-safe freon R236EA is considered, which has a “dry” saturation line characteristic, zero ozone layer destruction potential, and a global warming potential equal to 1370. It has been determined that increasing the parameters of the low-boiling working fluid in front of the low-pressure turbo expander (regardless of the scheme of the turbo expander cycle) does not always cause an increase in the exergetic efficiency. Thus, overheating of the working fluid at a pressure exceeding the critical pressure causes a positive exergetic effect, but for each temperature there is an optimal pressure at which the efficiency will be maximum. At a pressure below the critical pressure, overheating leads to a decrease in the exergetic efficiency, and the maximum exergetic effect is achieved in the absence of a secondary steam superheater. All other things being equal, a turbo-expander cycle with a heat exchanger is more efficient than without it over the entire temperature range and pressure of the low-boiling working fluid under study.
V. A. Sednin, Т. В. Бубырь
Science & Technique, Volume 20; doi:10.21122/2227-1031-2021-20-2-150-160

Abstract:
To increase the efficiency of operation of heating networks located in non-passable channels, a schematic and structural solution of regenerative-utilization heat use was previously proposed and at the same time it is shown that it isdifficult to create an acceptable full-scale experimental installation or the difficulty of conducting a passive experiment on existing heating mains in non-passable channels. As an alternative solution for performing research, it is proposed to create and use a virtual experimental setup developed on the basis of the ANSYS software package, which has received wide recognition in the world. The initial results of model verification showed that the study of heat transfer and aerodynamics in blown-through non-passable heating mains using such a solution is promising. A study has been carried out using a virtual experimental setup based on a six-factor second-order rotatble plan containing 46 points on a hypersphere with six star points. It is shown that there is no need to randomize the order of conducting and repeating the study at the points of computational experiment plan. Second-order regression equations have obtained for calculating a complex of objective functions: the required air pressure to achieve a given flow rate, the intensity of heat transfer directly from the pipes of the heating main, as well as from the walls of the channel to the blown air. The geometry of the channels of typical standard sizes of heating mains, the length of the sections, the temperature of the outside air and soil, and the air flow rate in the channel have been taken as the influencing factors in the calculations. For the obtained regression equations, significant coefficients have been established and the transition from dimensionless to natural factors has been carried out. The adequacy of the obtained regression equations has been determined using standard statistical estimation methods based on the calculated values of the Fisher’s, Student’s and other criteria.
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