Modeling of batteries is necessary to control their operating mode and diagnose their condition. It is important to model the life cycle, i. e. degradation of basic parameters over a long service life. This is due to the fact that the cost of buffering electricity by batteries is associated with their cycling resource, which can be increased by optimizing the mode of operation of the drive in the energy system. The existing models of battery degradation are characterized by specificity, limited work on standardized charge-discharge cycles, and mathematical cumbersomeness. The article proposes a universal approach devoid of the above disadvantages. The concept of continuous battery wear during the service life is used. A simple empirical model is presented that does not consider in detail the characteristics of the state of batteries during a separate charge-discharge cycle, and does not include voltaic variables. The model considers the intensity of the current wear of the battery as a function of the state of its charge, temperature, the current of the external circuit and the current of self-discharge, the full charge that has flowed through the battery since the beginning of its operation. In this case, the amount of wear (degradation) is determined by the integral of the function of the intensity of current wear over the battery life. To optimize the parameters of the model, a random search method is used in combination with a genetic selection algorithm. The corresponding model of degradation of parameters for the Delta GEL-12-55 lead-acid battery has been constructed, in which the data on degradation of capacity given in the technical description from the manufacturer are used. The efficiency of the parameter optimization algorithm and the adequacy of the resulting model are shown. The model developed by the authors can be used for technical and economic calculations of generator – storage –consumer systems, hybrid power storage systems, and compact representation of large volumes of experimental data on the degradation of specific batteries.

The necessity of modeling the operating modes of outdoor lighting lines with a voltage of 0.23/0.4 kV is substantiated. The choice of the optimal configuration of the lighting line while ensuring the standardized values of illumination and brightness on the working surface is recommended to be carried out by comparing several variants with different positions of pillars, types of light intensity curves, the number and power of luminaires. The results of the lighting calculation are the basis for modeling the electrical operation modes of outdoor lighting lines, which allows determining the operating parameters (node voltage, active and reactive power, current, voltage drop, loss of active and reactive power in individual sections). The obtained data can be used to select the cross-sectional area of conductor cores and forecast the power consumption of outdoor lighting, taking into account the specific features of light flux regulation (dimming). As a rule, outdoor lighting lines are connected to one power point. The use of outdoor lighting lines with bilateral supply for main streets and circular roads of relatively long length is proposed which will not only make it possible to increase the reliability of power supply of lighting installations, but also to use conductors with a smaller cross-section area of the cores. The electrical load of light sources is assumed on the basis of static characteristics. Modeling of the electrical modes of the outdoor lighting network is carried out taking into account the higher harmonics of current and voltage. The rational operation mode of the outdoor lighting line is determined by the magnitude of the voltage deviation from the nominal value, the indicators of non-sinusoidality and voltage asymmetry at the power supply point. Additional possibilities for modeling the modes of operation of lighting lines are to search for damage (detection of short circuits, determination of the presence of faulty lamps).

In the present-day conditions, the issue of energy saving is becoming increasingly acute and permanently relevant. This situation is caused by rapid growth in prices for primary energy resources and by the need to reduce the share of natural gas in the incoming part of the energy balance of Belarus. According to available statistics, with the commissioning of the Belarusian NPP, the share of natural gas in the incoming part of the energy balance decreases from 97 to 59 %. In the economic complex, the share of this primary energy resource is projected at 70 %. The problem of energy saving is solved most rationally and with the least investment only by increasing the efficiency of natural gas use, especially due to the commissioning of the Belarusian NPP, the issue of preserving the possibility of using centralized heating facilities is acute. It is necessary to increase the thermodynamic efficiency of the cycles of steam turbine plants, both heating and condensing, which form the basis of the generation of the Belarusian power system, in order to restore the energy characteristics of the power system, which have somewhat decreased with the commissioning of the NPP. In the limit, the share of natural gas in the incoming part of the energy balance should be reduced to values not exceeding 50 %, in accordance with the requirements of energy security. The article considers examples of utilization of low-temperature secondary energy flows occurring at thermal power plants: the heat of the cooling processes of the generator, lubrication systems, as well as the heat of condensation of turbine exhaust steam and deeper cooling of flue gases. On the basis of this review, it is expected to identify promising areas of relevant research in relation to the energy system of Belarus.

The main purpose of the article is to compare and analyze existing technologies for extracting carbon dioxide from combustion products in relation to mini-CHP plants operating on local fuels. The article presents a brief overview of the main technical features of the implementation of carbon dioxide extraction technologies from gas mixtures. The specific features and limitations for each of the methods are shown. Mathematical modeling of technological processes of adsorption, physical and chemical absorption is carried out on the basis of Aspen Hysys and Aspen Adsorption software packages. When modeling absorption processes, the composition of combustion products characteristic of the actual operating conditions of an energy source on wood chips was considered, while for the adsorption process, the composition of combustion products was simulated by a binary mixture of carbon dioxide and nitrogen with a molar content of 11 and 89 %, respectively. The results of numerical research that were obtained have shown that the highest degree of carbon dioxide extraction from combustion products is 97 %, and it is achieved in the optimal mode of implementation of chemical absorption technology. With the same method, the highest degree of purity of the resulting carbon dioxide is observed, viz. 86 % taking into account water vapor and 99 % if it is dry. The least effective technology for extracting carbon dioxide was the method of physical absorption in a fixed bed, in which the degree of purity of the resulting dry carbon dioxide was 79 %. Therefore, for practical use in the deep utilization of combustion products of mini-CHP plants operating on local fuels, to obtain carbon dioxide with a low content of impurities, it is necessary to apply the method of chemical absorption. The use of physical absorption technology in a fixed bed can be used to reduce energy source emissions or in cases where the degree of purity of carbon dioxide does not matter.

The article is devoted to the modernization of typical cascade automatic control systems with stabilizing and corrective PI controllers. Such automatic control systems, in addition to the main signal (of adjustable value), use an additional leading signal that reacts to the disturbance faster than the main one. The leading signal effectively compensates for internal disturbances arising in the system by adjusting the stabilizing controller. The temperature control system of superheated steam boiler units of thermal power plants may be taken as an example. The task of determining the configuration parameters of such dual-circuit systems is quite difficult. With a relatively low inertia of the internal circuit, the speed of the stabilizing controller is quite high, and transients in it do not affect the quality of regulation in the external circuit with a corrective controller. This makes it possible to calculate the optimal settings of the latter only by the dynamic characteristics of the inertial section using conventional methods developed for single-circuit systems. The main disadvantage of such automatic control systems is that they do not allow, with close inertia of the contours, to significantly improve the quality of working out the main impacts during the jump of the task, internal and external disturbances. To eliminate this drawback, an invariant cascade automatic control system with an internal model is proposed that takes into account the dynamics of both the internal and external contours with an inertial section of the object when choosing the structure and setting up the corrective controller. In this case, the internal model is used to fully compensate for the main feedback of the system when working out the task signal, as well as to isolate an equivalent external disturbance, for which an invariance differentiator is used to compensate. The invariant cascade automatic control system makes it possible to significantly increase the speed and accuracy compared to the standard one.

The work is devoted to an experimental study of the process of dissolution of a magnetic fluid in a nonmagnetic solvent under the action of a uniform magnetic field. It is experimentally established that in a volume of magnetic fluid surrounded by a miscible solvent fluid, under the action of a uniform magnetic field, a mechanical movement arises, triggering deformation of this volume. Initially, the axisymmetric volume of the fluid takes an ellipsoidal shape, lengthening along the magnetic field direction. The main reason for this movement is the pressure differences in the magnetic fluid, caused by jumps and nonuniformities of the magnetic field at the interface between magnetic and nonmagnetic media. Simultaneously with the mechanical motion, the diffusion dissolution of the magnetic fluid occurs, which is also accompanied by the motion of the diffusion front at the interface between the fluids. The concentration gradients of magnetic particles that arise in this case cause gradients of the magnetization of the fluid and, as a consequence, gradients of the magnetic field intensity. Together, this triggers the appearance of a bulk magnetic force in the magnetic fluid, and the pressure gradients associated with it. The main regularities of this process have been established, viz. the dependence of change of the geometric characteristics of the volume and its deformation rate on time. It is shown that at the initial stage of the process, the rates of mechanical movement of the boundaries of the magnetic fluid volume are much higher than the rates of movement of the diffusion front. Thus, the initial rate of mechanical elongation of the droplet under the experimental conditions is 0.25 mm/min, and the diffusion front rate is 0.08 mm/min. Over time, these processes slow down and stop when the volume of the magnetic fluid is completely dissolved. Herewith, the mechanical elongation of the drop is the first to stop and, in the case under consideration, takes about ten minutes.

The molten carbonate fuel cell allows for capturing, separating and concentrating CO₂ as it passes through the carbonate melt from the cathode side to the anode side, while simultaneously generating electricity and heat. The article presents the technology and flow diagram of a system for capturing CO₂ from flue gases of a thermal power plant in a high-temperature fuel cell on molten carbonates with subsequent conversion and utilization of gaseous combustible products in the energy cycle of a thermal power plant. The fuel cell runs on natural gas with internal reforming. After the fuel cell, the gas leaving the anode is sent to the conversion unit where, in reaction with carbon at high temperatures, combustible gases are formed that are suitable for re-combustion in the turbine. For power plants and a system for capturing and converting carbon dioxide, thermodynamic, technical and economic calculations were carried out. The efficiency of a high-temperature fuel cell is 42 %. In the baseline scenario, the net energy efficiency of the plant is 61 % while a CO₂ capture ration is 80–85 %. The return of fuel gases after the conversion of carbon dioxide, taking into account their calorific value, makes it possible to additionally increase the electric power of the thermal power plant up to 20 %. With a unit cost of a fuel cell of 1300 EUR/kW and a price of natural gas of 0.04 EUR/kW, the total electricity cost of the plant is 0.074 EUR/kW. The results show that the proposed system is attractive for natural gas power generation with CO₂ capture.