RELEVANCE. Synchronization is an algorithm of actions to switch on synchronous generators for parallel operation with the power system and is an integral part of the power generation process. In practice, the process of synchronization involves some difficulties. The developed automatic synchronization device is digital and is integrated into the microprocessor terminal of the CPA-M complex, allowing to solve the arising problems by means of synchronization using different methods, including the developed method of accelerated synchronization.

THE PURPOSE. Create a comprehensive automated synchronization system based on the CPA-M microprocessor terminal (manufactured by a Novosibirsk company) with a variability of methods. Analyze existing synchronization devices, synthesize traditional synchronization methods, create a non-traditional intermediate method on their basis and integrate it into the automated system. Develop algorithms for the measuring and logical units, as well as for the synchronization system output unit. Experimental testing of algorithms by feeding real signals from voltage sensors on a physical model with a rotating synchronous machine (12 kW generator under test).

METHODS. The problem of research studied using theoretical and practical approaches. Theoretical methods - analysis, synthesis and classification. Practical methods - modeling in MatLab® environment, comparison, experiment, observation.

RESULTS. The paper describes the architecture, construction principles, settings selection of the synchronization system, as well as the interaction of its logical part with adjacent units (measuring unit, output unit). The work gives a comprehensive description of the system setup and integration of its measuring and logic parts into the CPA-M microprocessor terminal with a test on a physical object.

CONCLUSION. The system has extended functionality compared to analogs, allowing the use of traditional methods and the developed method of accelerated synchronization. The results predict reduction of capital costs for automation systems, as one device provides synchronization on several circuit breakers and reduction of generator operation costs, as using this system, machine parts exposed to unacceptable thermal and mechanical effects. The development is relevant for the elimination of emergencies in the power system and reducing thermal and dynamic impacts on the generator. The social importance of the project is the exclusion of the human factor. The prospect of using the development - in the educational process of the university and at real power facilities, in particular on large synchronous generators.

RELEVANCE. Unbalance of loads adversely affects both the work of consumers and the electrical network itself. This phenomenon leads to a decrease in the efficiency of the processes of transmission and distribution of electrical energy due to the appearance of additional losses. Balancing of loads in electrical networks of 0.4 kV is carried out both at the design stage of networks and during their operation. At the design stage, they try to evenly distribute the loads across the phases. The authors of the article solve the actual problem of distributing single-phase electrical consumers at the stage of designing a power supply system to analyze the total share of additional losses from unbalance in the structure of total losses in distribution networks of 0.4 kV.

THE PURPOSE. To consider the problem of unbalance of loads in electrical 0.4 kV networks, causing additional losses of electricity. To analyze the existing methods of balancing when distributing the phases of the lines L1, L2, L3 of single-phase power receivers at the stage of designing electrical networks. Develop an algorithm for single-phase power consumer distribution, using arrays of instantaneous values of the current strength of individual electrical receivers as initial data. It stipulates calculating the best distribution of power consumers across the phases of lines L1, L2, L3 using the minimization of the load unbalance impact on the losses in power grid elements used for the electric power transfer.

METHODS. To solve this problem, the authors employed the complete enumeration method implemented with a tertiary numerical system used to code power consumer distribution across the power supply grid phases. The coefficient accounting for the unbalance of load distribution across power grid phases is used as the target function.

RESULTS. The developed algorithm can be applied as an external plug-in for the design software package to distribute the power consumers of one of the rooms in a BIM office building. The developed algorithm is compared to the existing widely-used approaches to single-phase power consumer distribution in power grids.

CONCLUSION. The developed algorithm allowed producing brand-new engineering solutions while developing a design document for the power supply grid (design and detailed documentation stage). They help improve the efficiency of electric power transmission by reducing additional losses caused by unbalanced loads.

RELEVANCE. The effective functioning of urban water supply systems plays an important role in maintaining the normal life of cities and towns. Of particular importance is the management of pressure and the optimization of hydraulic regimes in water-wired networks, since they directly affect the reliability of water supply and the efficient use of resources. However, the determination of the optimal parameters and methods of regulation in each specific case requires careful research and analysis. In the context of a constant increase in requirements for automation of water supply and growing investments in its infrastructure, the problem of a correct feasibility study for such investments is of particular relevance.

PURPOSE. For smooth regulation of the pressure characteristic of the pump in the conditions of the need to maintain a given pressure of the water supply network, frequency converters are widely used. In the context of the significance of an accurate assessment of investment costs for the automation of pumping units, it becomes necessary to obtain equations that take into account the features of the operation of the water supply network at the pre-design stage. In this regard, the authors of the article set themselves the goal of studying the degree of influence of the static component of the water supply network on the change in the power consumption of the pumping unit with frequency regulation and testing the obtained dependencies on real statistics of the water and energy consumption modes of the Sozh water intake of the Gomel water utility.

METHODS. To solve the tasks, classical formulas of similarity of the pumping unit were used, reflecting the relationship between flow, pressure and power consumption. The mean squared error, the mean absolute error and the average absolute error in percentages were used as the evaluation metric for verifying the electric power supply model of the pumping unit.

RESULTS. The study demonstrates a significant improvement in the accuracy of power consumption modeling when using a modified coefficient reflecting the degree of power change when the frequency of the supply network changes. When using this approach, the standard error is reduced more than twice, from 0.35 to 0.167, the average absolute error is reduced from 0.347 to 0.165, and the average absolute percentage error is reduced from 0.20% to 0.08%.

CONCLUSION The conducted research confirms the effectiveness of the use of frequency control of pumping units, which provides a nonlinear change in electrical power, and demonstrates the possibility of more accurate forecasting of electricity consumption, taking into account the specifics of the water supply network. The results of this work can be useful for projects to optimize urban water supply systems, providing more accurate planning and use of resources.

RELEVANCE. Improving the efficiency of the plant with an increase in operating capacity is one of the priority tasks of the development of power plants. One of the solutions to this issue is the introduction of fuel cells as the main or additional source of power and heat. The development of a high-quality scheme for the introduction of fuel cells into thermal power plants will increase their production capacity with the possibility of further reducing the carbon footprint by reducing the consumption of natural gas.

THE PURPOSE. To develop thermal power plant schemes in combination with fuel cells to increase the thermal efficiency of the thermal power plant. To consider the types of fuel cells and the principle of their operation and to analyze their effectiveness with justification of the choice of a specific type for further calculations. To study the methods and principles of hydrogen extraction with the choice of the optimal solution directly within the framework of this work. Perform a technical and economic analysis of the introduction of fuel cells to the station.

METHODS. When solving this problem, we used a method based on the law of conservation of energy under stationary operating conditions of the circuits was used. The chosen calculation method was implemented using MatLab, DvigWT and Microsoft Excel software.

RESULTS. This article presents three types of thermal power plant schemes in a layout with fuel cells and an indication of their specific advantages and disadvantages. The analysis of methods of hydrogen extraction with the choice of one of them by performing an estimate of the cost of hydrogen production is carried out. A technical and economic analysis of the introduction of fuel cells at the plant has been carried out, taking into account the cost of hydrogen production. The carbon footprint from the introduction of fuel cells at the station has been calculated.

CONCLUSION. Using fuel cells at the CHP increases the production efficiency of electricity generation by more than 20%, and the power of the power generation unit increases by more than 30 MW. Calculations have shown that the use of fuel cells leads to a significant increase in production capacity, but it is necessary to study in more detail the methodology for calculating the fuel cells themselves and the ways of hydrogen production.

OBJECT. Experimental studies on optimization of the output electrical and mass transfer characteristics of the reverse electrodialysis process.

METHODS. System analysis techniques were used in this work and a mathematical model was developed to describe the movement of water streams and the concentrations of substances in them. The equipment involved, designed for experimental and industrial testing of the proposed technologies with technical characteristics of the developed apparatuses and installations, is described.

RESULTS. RED (reverse electrodialysis) is a new membrane technology for renewable energy production using salinity gradients. The ultimate goal of RED is to achieve the highest possible value of power density, which depends on several parameters related to the intrinsic electrochemical characteristics of the membranes, stack configuration (number of cell pairs, channel length), hydrodynamics, nature of the working solutions (ionic composition, concentration), and others. The paper presents experimental studies on the influence and modeling of various parameters of the reverse electrodialysis operation on the output electrical characteristics of the system.

CONCLUSIONS. It is shown that the system output power is significantly influenced by the composition of solutions in the near-electrode chambers, external load and internal resistance, concentrations of working solutions and time of the experiment. The maximum electrical efficiency was 56% (power density 0.34 W/m2) in semi-industrial electrodialysis reverse electrodialysis experiments using model NaCl solutions, K₃Fe(CN)₆/K₄Fe(CN)₆ and Chinese 0.6 mm thick IONSEP membranes.

RELEVANCE. Due to the difficulties of finding eigenvalues and proper functions for bodies with axial (cylinder) and central (ball) symmetries defined in classical methods from the edge Sturm-Liouville problems, including Bessel equations whose exact analytical solutions are not obtained (known only numerical solutions, described by approximation formulas), there is a need to develop analytical methods of their solution.

THE PURPOSE. Using orthogonal methods of weighted residuals, an approximate analytical method for determining eigenfunctions and eigenvalues in boundary value problems with axial and central symmetry (cylinder, ball) has been developed.

METHODS. The method is based on the use of orthogonal systems of coordinate functions and additional boundary conditions. Latter are in such a form that their fulfillment by the desired solution is equivalent to the fulfillment of the differential equation of the boundary value problem at the boundary points of the region, leading to its fulfillment inside the considered region. Moreover, the accuracy of the equation depends on the number of approximations, which, in turn, depends on the number of additional boundary conditions used. Using the orthogonality property of trigonometric coordinate functions included in a series representing eigenfunctions makes it possible to increase the accuracy of the fulfillment of the differential equation of the Sturm-Liouville boundary value problem and the accuracy of determining the eigenvalues. To satisfy the initial condition, its residual is compiled and the condition of its orthogonality to all coordinate functions is required. The orthogonality of trigonometric systems of coordinate functions with respect to the unknown constants of integration leads to a system of algebraic linear equations, the number of which is equal to the number of approximations. As a result, the fulfillment of the initial condition is simplified and the accuracy of its fulfillment is increased.

RESULTS. The advantage of the method is that the resulting solution contains only simple algebraic expressions, excluding special functions (Bessel function, Legendre function, gamma function).

CONCLUSION. Thus, bypassing direct integration over a spatial variable, the use of additional boundary conditions makes it possible to find a solution of any complexity of the equations of the Sturm-Liouville boundary value problem, which reduces to the definition of simple integrals.

RELEVANCE. A review of the current state of research on coal-water slurries in Russia and abroad is presented. Coal-water slurries are promising alternative types of energy fuels. Their use in the energy sector will allow generating thermal and electrical energy. It is possible to use a fairly wide range of substances as components of such fuels. One of the preferred types are various waste. The analysis of modern literature has shown a fairly wide range of directions for the study of multicomponent coal-water slurries.

THE PURPOSE. To provide information on the current state of research in the field of technologies for the preparation, spraying and combustion of coal-water fuels, as well as on existing and promising additives to such slurries.

METHODS. The study was carried out by the method of collecting and structuring information.

RESULTS. The review of the current state of research in the field of technologies for the preparation, spraying and combustion of coal-water fuels, as well as existing and promising additives to such slurries, was carried out. It was found that additives of liquid combustible waste and biomass contribute to reducing the ignition delay time. At the same time, such additives do not reduce the quality characteristics of spraying multicomponent coal-water slurries. A number of components reduces the amount of emissions of combustion products of such fuels into the atmosphere. The influence of additives and components of coal-water slurries on their characteristics and properties was analyzed. It was shown that liquid components contribute to the intensification of ignition and combustion processes. In addition, their introduction into the fuel composition has a positive effect on the rheological properties of slurries, the characteristics of their spraying, combustion and the concentration of harmful emissions.

CONCLUSION. Coal-water slurries are promising alternative types of energy fuels. The introduction of combustible components into the composition of coal-water slurries can significantly improve the rheological properties, which can improve the storage and transportation characteristics of such fuels. The established positive characteristics and properties of coal-water slurries provide prerequisites for the full-scale introduction of such fuels into industrial power engineering.

RELEVANCE. The impossibility of using existing information systems, such as territorial waste management schemes (TSOs) to form a balance of supply and demand. TSOs do not allow us to identify the volume of demand and supply for processing technologies, and equipment manufacturers are not focused on understanding the balance of demand across the country. Technological development in terms of creating new facilities for energy waste processing requires justification of prospects for investment.

THE PURPOSE. Develop the concept of a closed resource cycle using information flows aimed at identifying participants in the process. The desired tool should provide an understanding of the need for the production of bioenergy equipment, the potential for demand for R&D, as well as the formation of state programs to support the creation of enterprises for the processing of municipal solid waste (MSW) and the production of bioenergy equipment.

METHODS. The development of the concept of a closed resource cycle is characterized by the design of the concept, which includes the methods of divergence, transformation, and convergence.

RESULTS. The paper describes the relevance of the topic associated with the impossibility of using existing information systems such as territorial waste management schemes (TSMS) to form a balance of supply and demand for processing technologies. Potential participants in the formation of a closed resource cycle throughout the life cycle of a waste processing project are identified, with the role of participants and the links between them, as well as the characteristics of the information flow of each participant, identified. A concept is proposed based on the formation of an information system in which each participant can maximize their needs for resources and effect.

CONCLUSION. The proposed system makes it possible to improve the existing waste management system, ensures the return of generated waste to the resource cycle. systems - the balance of generated and recycled waste. The main difference between the proposed system and the federal state information system for accounting and control of waste management of classes I and II is the principle of operation - the system is based on the source of waste generation, ensuring the balance of generating and processed waste.