CuInSe2 thin-film solar cells are promising materials for photovoltaic devices. One of the main tasks of researchers is to find ways to increase the solar cells efficiency. In this paper we propose an original structure of a thin-film solar cell based on a tandem connection of a photoelectric converter and a thermoelectric layer based on CuInSe2. The photoelectric converter consists of CuInSe2 and CdS layers. A 3D model of the proposed thin-film solar cell was implemented in the COMSOL Multiphysics environment with using the Heat Transfer module. The simulation was carried out taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the AM1.5 solar spectrum for the geographical coordinates of Minsk. The solar radiation power density of about 500 kW/m2 can be achieved by using concentrators. The temperature pattern and temperature gradients are calculated in each layer of the solar cell without and with the temperature stabilization of the substrate back side as well as without and with the thermal insulation of the substrate ends. Graphs of the temperature gradients of the thermoelectric layer and the temperature variations of the photoelectric converter of the solar cell are given. As a result of the simulation, it is shown how the uneven heating of both the surface of a thin-film solar cell and its layers occur under conditions of diurnal and seasonal variations of both the ambient temperature and the solar radiation power density. Under concentrated solar radiation exposure, the photoelectric converter surface can be heated up to 700 °C without temperature stabilization of the solar cell substrate. The operating temperature of the photoelectric converter was maintained at no more than 2.35 °C in January and at no more than 14.23 °C in July due to the temperature stabilization of the substrate back side of the proposed device. This made it possible to achieve an increase in the output power of the solar cell both by summing the photoand thermoelectric output voltages and by the concentration of solar radiation.

The methods of determination the fault zone according to the parameters of the emergency mode, which can be used to improve the performance of technical perfection of current protection lines of distributive 6–10 kV one-way power networks, are considered. The advantage of the algorithm of determination the zones of short circuit (SC) according to the level of emergency currents as compared to the remote unilateral method addressing the parameters of the damaged loop corrupted loops (loops) is noted. Calculation of the estimated distance to the point of SC on the basis of difference of damaged phase currents has been proposed, that enables the independence of the obtained result on the type of the fault. A technique for increasing the reliability of the method for determination the short-circuit zone by the level of emergency currents based on information about the type of damage has also been proposed. The effect of load currents and contact resistances of different levels on the magnitude and nature of the changes in the errors of the calculated distance to the short circuit was investigated by the method of computational experiment. The levels of contact resistances relative to the total resistance of the line depending on the place of SC occurrence are determined that provides reliable determination of the fault zone; it is demonstrated that the nature of their alteration is approximately the same for lines of medium and long length. The expediency of correction of the calculated distance to the fault location in many cases of short circuits through the contact resistance so to improve the protection capacity of the high-speed current protection stage is demonstrated. Based on the results of the computational experiment, correction factors for the correction of the value of the emergency current have been obtained; on the basis of the latter the fault zone is determined. The estimation of efficiency of the proposed method of correction has been carried out; it is shown that its application makes it possible to improve the accuracy of determination the fault zone and to expand the zone of instantaneous shutdown of short circuit. The dynamic properties of the proposed algorithm for different modes of the line operation have been investigated; it is ascertained that, in the worst case, the determination of the short circuit zone for a time not exceeding 27 ms is provided.

. New conditions of functioning of electric power industry, tougher of requirements to technological condition of the industry predetermined transition to restructuring of electric networks on the basis of innovative structure of SMART GRID. This leads to the improvement of traditional tasks of calculation and analysis of modes and technological consumption (loss) of electricity. The authors have developed a promising method of operational calculations of technical losses of electricity in modern electrical networks of 0.38–10 kV on the basis of telemechanical graphs of loads on the head sections of distribution lines, in the area of additional installation of digital metering devices and of sources of distributed generation. The method proposes a new technique for determining the flow of electric energy in the sections of distribution lines. This is done as follows. First, according to the data of additional measurements of the network and taking into account the calculated no-load losses of transformers, electricity flows are calculated in the head sections of 6–10 kV lines. Then, according to the obtained data and the measured values of the active and reactive energy graphs of the head sections, the electric power flows targeted for their subsequent distribution over all sections of the 0.38–10 kV network are determined, taking into account the load losses of electricity and the flow distribution coefficients. The distribution coefficients are the fractions of the calculated phase loads of the 0.38 kV network of their total value. Then, according to the obtained data and the measured values of the active and reactive energy graphs on the head sections, the electric power flows intended for their subsequent distribution over all sections of the 0.38–10 kV network are determined, taking into account the load losses of electricity and the flow distribution coefficients. The basic analytical relations concerning the estimation of losses and mode as well as an example of calculation of technological consumption (loss) of electricity in the general scheme of the distribution network of 0.38; 6 and 10 kV are given. The latter is performed for a single (first)stage of load graphs.

Reliability of operation of power systems is determined by reliability of the power equipment, and reliability of the measuring information characterizing a condition of power equipment and the technological processes of generation, transfer, distribution and consumption of energy proceeding in it. Unreliable information causes errors in the diagnosis of equipment malfunctions, improper operation of process control systems and reduction the operational technical and economic performance of power systems. Along with the methods of hardware control of the reliability of measurements using digital codes, there are methods of software and logic control based on the technological meaning of the measured data, their logical consistency and consistency. Control of reliability of measurements by limit values is often applied when the result of measurement of a variable is compared with its known upper and lower limits of reliable values. The resolution of the control by limit values is sharply decreased with the expansion of the range of reliable values. The article deals with the reliability control based on the analysis of the rate of alteration of the controlled variables. At control in accordance with the first increments, the first increment, i.e. the difference of results of measurements in the current and previous moments of time is compared with the known range of the first increments of reliable results of measurements. Control in accordance with the first increments is most effective in cases where the controlled processes are sufficiently inertial and the rate of alteration of variables is relatively small. The resolution of the control by the first increment can be enhanced through the use of extrapolation filters. In this case, the current measured value of the variable is compared with its extrapolated value at the previous time and the result of the comparison reveals an incorrect measurement result.

It is found that the voltage at the lowest points of the wire or cable sag and at the points of their suspension on the pillars in the same span, determined in accordance with the properties of a perfectly flexible filament (similar to which the wires and cables are located in the span), differ slightly, and taking the difference of the mentioned values into account is only of methodologycal importance. The article presents the results of the calculation of wire and cable sag of large spans of power transmission line of 500 m or more length using both the traditional theory of the catenary line and the theory of equal resistance, when the cross-sectional area of a wire or cable, proportional to their tension, is considered variable in the span length, which provides the same probability of breaking them at any point of the span. When calculating the wires and cables in normal and emergency conditions, the largest sags are determined, which take place either at a higher ambient temperature or at a load of the wire with ice. The wire must be mounted in such a way as to ensure the normalized permissible dimensions to crossed engineering structures, water barriers or land, that are determined depending on the nominal voltage of the line. It is noted that the values of the wire and cable sags determined using the theory of the catenary line for the transition spans are less (although slightly) as compared to the data obtained on the basis of the theory of the equal resistance circuit. This must be taken into account in the design process.

The article presents the development of an intelligent control system for LED lighting, applicable to autonomous electric lighting installations, outdoor lighting fixtures on posts to illuminate highways, roads, streets and surrounding areas. The system combines all local lighting systems in which the motion sensor and the LED luminaire are integrated into one network. Turning on the LED luminaire at reduced power is carried out automatically when the level of external natural light is less than a certain threshold value. In the case of appearance of an object moving along the motion sensors of neighboring local lighting systems, the speed and direction of movement of the object are determined. In accordance to the speed and direction of the object movement the number of local lighting systems is determined whose LED lamps should be switched on at a higher power and the appearance of the object at the next design point is predicted. The increase in the power of LED lamps is carried out smoothly when the object is approaching the corresponding local lighting system. Due to the dynamic control of the power of the LED luminaires, as moving objects appear in the coverage area of the intelligent lighting system, significant energy savings are achieved. Traffic safety conditions are increased, as the number of LED lamps operating with increased power is determined by the speed of the object, and its possible braking distance will be significantly less than the illuminated section of the roadway. Smooth changes in the power of LED lamps reduce the pressure on the driver of the vehicle. The choice of the motion sensor based on the autodyne radio blocking, which detects moving objects in a given sector of the controlled space, regardless of the time of day and weather conditions, is grounded.

The problem of parametric optimization of automatic control systems of power units (ACSPU) of 300 MW at the Lukoml’skaya GRES (Lukoml Condensing Power Plant) at a constant superheated steam pressure upstream of the turbine is under consideration. During 1974–1979, eight units of the Lukoml’skaya GRES implemented ACSPU with a leading boiler power control, which will be forced to work in a wide range of loads due to the planned commissioning of two power units of the Belarusian NPP: the first one – in 2019, and the second one – in 2020. The total capacity of the Belarusian Nuclear Power Plant will amount to 2400 MW. In addition, modern requirements for the regulation of the frequency and flows of active electric power in the power system have been tightened: the time to reach the half value of the required power alteration should be 10 seconds within the normal and emergency reserves; the time to reach the full value of the required power alteration should be 30 seconds within the range of the normal reserve and 2 minutes – within the range of the emergency reserve. With this regard, increasing the efficiency of the units operating in the variable part of the electric load schеdule by the use of modern methods of calculation of parameters of the dynamic adjustment of the regulating devices of ACSPU becomes an urgent problem. The methodology of parametric optimization of the typical ACSPU that make it possible to improve the quality of power regulation and the pressure of the superheated steam upstream of the turbine is presented. The described technique is illustrated by the results of computer simulation of transient processes in the system when the task and internal disturbances are worked out, which confirm the correctness of the proposed technique in comparison with the known methods of optimization of the typical ACSPU.

According to field observations, currently in the Republic there is an active destruction of the bedrock costs and slopes of more than 80 % of water bodies. The total length of the coasts of reservoirs that are subjected to processing is about 350 km with a maximum regression of more than 40 m. The reasons of activation of process of processing of the coast caused by construction of new reservoirs of power engineering purpose are considered. The length of the coasts of the new reservoirs exposed to abrasion processing will increase in the near future by more than 30 km, which will have some impact on the surrounding areas and objects of the regional economy. As for the channel-type reservoirs, processing of the cost is being expanded only in the near-dam part of the reservoir and reaches 40 % of the coastline. At the same time, the value of this indicator might be up to 70 % of the length of the coasts of the lake-type reservoirs. Having taken this problem into account, it became necessary to generalize the corresponding accumulated factual data and the results of scientific research. Therefore, the results of theoretical studies of the process of processing of coastal slopes of reservoirs of hydroelectric power plants of Belarus presented by the author, along with the updated data, are of practical importance for decision-making in the regulation of engineering activities for coastal protection. The article presents the theoretical issues of the development of abrasion processes in the banks of reservoirs of hydroelectric power plants in Belarus, based on the data of field observations and laboratory studies. On the basis of the law of conservation of mass and taking into account hydrological features of reservoirs, geological structure of relief and granulometric composition of soils forming the bank, balance mathematical models of development of the equilibrium coastline and the profile of the dynamic equilibrium of the banks that are subjected to processing are developed, criteria for the stability of slopes have been obtained.