THE PURPOSE. In remote areas in the absence of centralized power supply, energy conservation is one of the key factors for the successful development of the region. The use of electrochemical energy storage systems contributes to the saving of liquid or gaseous fuel of power plants used in autonomous power supply systems. Domestic manufacturers have created modular-type mobile energy storage systems designed for their rapid deployment in almost any territory and operating in the range from several hundred kilowatts in a single design to complexes of tens of megawatts. METHOD. The method of indefinite Lagrange multipliers was used in application to the power profiles of the load of a discrete form to select the parameters of the electrochemical energy storage, causing the minimization of fuel consumption. The obtained mathematical model uses the power profiles of the load, formed by its duration, and is focused on the simplest algorithm for the numerical search for the extremum of a function by changing its argument, without solving the optimization nonlinear equation. The method includes the choice of the duration of the discharge of the energy storage. RESULTS. The influence of the energy storage device on the reduction of fuel consumption is shown. The technique is valid for convex consumption characteristics of power plants. In the context of predicted changes in power profiles (work / weekend days), optimal control scenarios are calculated individually. CONCLUSION. The use of the proposed mathematical model provides quick calculations of the economic assessment of the use of electrochemical energy storage. For gas piston power plants, where they are required to stabilize the parameters of power quality, their commercial attractiveness is significantly higher than for power plants of another type.

PURPOSE. Purpose of the Work - To build a hybrid solar power plant and a gas turbine plant (ISCC), several important elements must be available. Making a decision in principle to build a hybrid power plant and determining its optimal location requires an analysis of many factors in Iraq. Iraq is a region rich in solar energy. Solar energy potential from an area of 437,072 km2 exceeds the current demand for electricity by hundreds of thousands of times. This will help Iraq to remain an energy exporter in the future by switching from fossil fuels to solar energy. METHOD- Determines the relevance of research in this area, namely the development of a multivariate mathematical model for finding the optimal location of a ISCC using the method of paired comparisons using the MATLAB program. RESULTS - Province Albasra is characterized by a significantly higher level of electricity consumption in the region, as well as a more developed infrastructure. This, in general, predetermines the highest final rating among all the provinces of Iraq as the optimal region for the location of a ISCC. CONCLUSION- Using the proposed mathematical model, a rating was calculated and a comparison was made of the provinces of Iraq to determine the best region for placing such ISCC. This mathematical model can be used for further localization of the solution to the problem, for example, when considering the best conditions for the construction of a hybrid power plant already within a province, etc.

THE PURPOSE. To assess the possibility of burning coal sludge, waste of coal preparation, in the furnaces of power boilers at the thermal power station of the Irkutsk region. METHODS. Technological and mathematical research methods were used to analyze the incineration of coal preparation waste. RESULTS. The article presents the experience of using coal preparation wastes from Cheremkhovsky coal at CHPP-12 of Irkutskenergo. Presented are the results of thermal tests of the TP-30 boiler at CHPP-12 during the trial combustion of granular waste from coal enrichment together with waste from marble production mixed with Golovinsky coal. As a result, it was revealed that the main parameters of the boiler operation practically did not change, there was a slight decrease in the temperature of the air mixture at the outlet of the mills in comparison with pure Golovinsky coal, which is due to the higher moisture content of the resulting mixture, in addition, there is a decrease in sulfur dioxide emissions by 18- 30% in depending on the proportion of granular waste of coal preparation in the mixture. CONCLUSIONS. Experimental studies carried out at CHPP-12 when burning Golovinsky coal mixed with granular waste of coal preparation in amounts up to 30% of the total amount of the mixture indicate that granular waste of coal preparation can be burned without any special restrictions in the operation of the equipment of the CHPP. Based on the results obtained, an analysis was carried out and recommendations for the incineration of coal preparation wastes were developed.

THE PURPOSE. Reveal the regularities of turn-to-turn faults influence on to parameters of a three-phase network transformer in the disconnected transformer mode with the supply of control voltages and currents from an external source in the transformer linear operation. METHODS. To achieve the purpose, experimental studies were carried out on the power transformer (Trihal with a voltage of 20 / 0.4 kV) with an artificially created turn-to-turn fault, mathematical modeling and calculations of the three-phase transformer magnetic system parameters. RESULTS. Experimental measurements of the open circuit voltage were performed on the power transformer high voltage side by applying a three-phase positive sequence voltage to the transformer low voltage side. Similar measurements were carried out using a three-phase zero sequence current. The influence of the turn-to-turn fault on the magnetic system of the three-phase transformer with the application of voltages and currents of zero and direct sequences is investigated. A mathematical model of three-phase transformer magnetic system has been developed, which makes it possible to determine the change in the parameters of the transformer windings and to establish the relationship between the primary and secondary voltages and currents in conditions of the occurrence of а turn-to-turn fault. The parameters of the three-phase transformer magnetic system were calculated from the results of experimental measurements. CONCLUSION. An effective method for detecting turn-to-turn faults by measurements with the supply of zero sequence currents is proposed. A simplified model of the three-phase transformer magnetic system has been developed. This model allows us to qualitatively evaluate the changes in the transformer parameters when a turn-to-turn fault occurs. A model of turn-to-turn fault is proposed, which can be used to study the effect of turnto- turn fault on the transformer magnetic system.

The fouling of heat exchange equipment leads to serious economic losses in many industries, therefore to find a method to reduce deposits on heat transfer surfaces remains an actual task. THE PURPOSE. In this paper, a practical solution is proposed for the implementation of a pulsating cleaning method of oil coolers as an example. METHODS. The influence of

pulsations on cleaning of the external surface of the heat exchanger is studied by computer modeling with Ansys Fluent. The fluid flow was described by the Navier-Stokes equation, particle motion and their interaction was described by the discrete element method (DEM). In the study, a staggered tube bundle was considered. The pulse frequency 0.3125 Hz, the amplitude referred to the diameter of tube is 35, the Reynolds number 100, the duty cycle of the pulsations 0.25.Oil was chosen as the medium. RESULTS. Evaluation of the pulsating cleaning method was carried out on the basis of the analysis of the mechanics of particle collisions on the surface of the central cylinder in the beam, with stationary and pulsating flow. It was found that the pulsating flow helps to reduce deposits in the front of the cylinder and is not effective in the back. CONCLUSHION. An analysis of the mechanics of particle impact on the heat exchange surface showed that this pulsation mode is more effective for removing plastic deposits.

THE PURPOSE. To develop an apparatus for wave treatment of water-fuel oil and preparation of water-fuel emulsion for combustion. To present a scheme of an innovative vortex burner device for water-oil emulsion combustion. To review existing equipment for preparation of high quality emulsion. Refute the necessity of forced dehydration of fuel oil for high-quality combustion in burners. To present data on the choice of material for manufacturing the dispersant body, taking into account the requirements for corrosion resistance, as well as resistance to cavitation and wear resistance. To develop an experimental setup for the preparation of water-oil emulsion for combustion in a vortex burner. To conduct an analysis to identify the relationship of transformation of physical and chemical properties of water-oil emulsion (sedimentation and aggregative stability, structural viscosity) from temperature and volume of water in them. METHODS. Theoretical methods of viscosity and density determination were used in solving the problem and results were obtained experimentally, by using a capillary viscometer, in different temperature ranges of emulsified fuel preparation. A method was used to assess the clarification of the WFE to evaluate the sedimentation stability, with compulsory conditioning in glass cylinders in a statistical state. RESULTS. The preparation of WOE is conditioned by the water content rationing. The factor of partial loss of moisture at the plant during emulsion preparation can be considered as a positive side effect of dewatering. Data on the density of water-oil emulsion depending on the concentration of water at 70 0C has been obtained. The analysis of dependence of stability of emulsion based on fuel oil M-100 from time of settling at 20 0C is made. CONCLUSION. The presented wave dispersant experimentally demonstrates a high quality of VME preparation. Experimental results prove the presence of a significant numerical increase of the 10 μm particle size, as well as a minimum conversion of 1.25 μm particles towards the 2.5 μm particle size. The use of wave treatment dispersant results in stable water-oil emulsions suitable for use as fuels in the power industry.

THE PURPOSE. The purpose of the article is to define the reasons to improve the system of grounding devices design. Author studies technical decisions that reduce grounding resistance values. Results are given researches how a mineral conductive mixture, that normalizes grounding, influences a seasonal coefficient. Analysed the results of the experimental surveys. Аlso evaluates a test grounding devise’s resistance decrease compared to the resistance decrease of a control grounding device. METHODS. While solving the above problem, a number of field experiments were carried out to measure the resistance values of experimental circuit grounding devices after their near-electrode soil space had been treated with the mixture that improves the resistance of a grounding wire. RESULTS. The composition of the mixture that normalizes (reduces) soil electrical resistivity has been developed, it has contained hydro-stabilizing and lowdispersed conducting additives. There has been proposed the analytical expressions to evaluate equivalent soil electrical resistivity values after aporton of soil had been submitted by the mineral conducting mixture. CONCLUSION. The use of the mixtures based on hydrolyzed polyacrylonitrile is most effective together with the grounding wires buried in soil no deeper than the soil freezing depth that is located in the soil layers with maximum seasonal fluctuations, and will increase with the increase of the contact area of such grounding wires with the soil treated with hydrolyzed polyacrylonitrile. Additional decrease of a seasonal coefficient for the vertical compound grounding wires apparently is due to the mixture influencing their parts mounded near the ground surface. The use of complex mixtures containing both hydro-stabilizing additives and low-dispersed conducting substances allows up to three times decrease of the resistance values of a grounding device compared to a control grounding device, it allows to even seasonal fluctuation of resistance of a grounding device, and to decrease mounting capital investment for a grounding device by means of the decrease of the number of the electrodes and the territory on which they are located.

PURPOSE. To address the problems of the functioning of the SES. To develop algorithms for evaluating the parameters of the efficiency of the functioning of the systems of intra-plant power supply. To investigate the operability of low-voltage shop networks of radial, trunk and mixed structure in optimal operating conditions of the equipment when modeling the impact of external factors, such as the root-mean-square load factor of the equipment, the temperature of the shop room and the calculated time interval on the operating parameters of the system. As the operating parameters of the system are accepted: the value of the equivalent resistance of the low-voltage electrical network. the amount of active power loss and the amount of electricity loss in the low-voltage network. METHODS. Probabilistic and statistical methods for evaluating the functional parameters of systems were used to solve the tasks. RESULTS. The article considers the features of the functioning of low-voltage networks of intra-plant power supply systems. Models are developed and the performance characteristics of low-voltage electrical networks of various topologies are calculated depending on the main circuit and operating parameters of electrical equipment when the values of the limits of the intensity of external influences change. CONCLUSION. The use of probabilistic methods allows us to take into account the dynamics of the main parameters of in-plant power supply systems when evaluating the effectiveness of their functioning. The calculations showed how the performance characteristics of such systems change depending on the intervals of variation of external factors in the operating conditions. The results obtained allow us to recommend the use of the developed models for effective control of circuit and mode parameters of low-voltage electrical networks to improve the quality of power supply to consumers.

It is assumed that for external parameters of a random nature, the normal distribution is reliable. Algorithms for calculating the performance characteristics of in-plant power supply systems of various topologies and designs at different values of the limits of the intensity of external influences of the operating parameters are developed. At the same time, it is established that with an increase (decrease) in the intervals of changes in external parameters, their permissible intensity decreases (increases) in relation to the maximum intensity value for various operating modes of the equipment.

THE PURPOSE. To consider the problems of generator circuit breaker. To consider the problems of high degree of asymmetry of short-circuit current and long delayed current zeros in detail. Propose methods for solving these problems. Develop the equivalent electrical circuit model of electric power station. This model should demonstrate the above-mentioned problems and effectiveness of the proposed solving problems methods. METHODS. The fault transient’s simulations have been performed by means of the software package Matlab Simulink. RESULTS. The equivalent electrical circuit model of electric power station was proposed and developed. This model allows simulating the short circuit currents from a synchronous generator. Short-circuit current waveforms are obtained. These waveforms describe the problem of high degree of asymmetry and long delayed current zeros phenomenon. Proposed decision on using thyristorbased hybrid circuit breaker with PTC-thermistor-based current limiting device. For equivalent electrical circuit the PTC-thermistor model was developed. Short-circuit current waveforms when applying PTC-thermistor-based current limiting device are obtained. CONCLUSION. The simulation results showed that the effect of long delayed current zeros (when the current does not pass zero at its nearest minimum) is not typical for high-power synchronous generators (PSG > 300 MW). This effect can occur when the synchronous generator is operating in the reactive power compensation mode. At the same time, there should be no additional electric resistance (for example a gas electric arc). The use of PTC-thermistor for thyristor-based hybrid circuit breaker will reduce energy of short circuit current on ~25% and it will completely protect the circuit breaker from does not pass zero current. This will increase reliability of thyristor device for hybrid generator circuit breaker.

TARGET. PURPOSE. Bioenergy is aimed at the production of biological fuels, alternative to natural fossil fuels. Biofuel is obtained from plant or animal raw materials, from the waste products of organisms, from industrial waste, from agricultural waste, etc. The article studies the properties of coal from the Kuznetsk Basin with solid fuel compositions from local fuels and organic waste (biomass), as well as the possibility of their co-combustion in boilers of low and medium power. METHODS. To solve the set tasks in the scientific article, a computational and empirical research method was used - experiment. Experimental studies were carried out in the laboratories of the Department of Technologies in Energy and Oil and Gas Processing of the Kazan State Power Engineering University, in the laboratories of the Kazan CHP-1 branch of Tatenergo and the Kazan CHP-3 branch of TKG-16. As objects of research were selected: coal of the Kuznetsk coal basin; peat from the Sosnovoye deposit of the Republic of Tatarstan; sawdust obtained after processing deciduous trees; cake from processed oilseeds at Kazan Oil Extraction Plant JSC. In accordance with the current GOST, humidity (GOST R 52911-2013), ash content (GOST R 55661-2013), and the yield of volatile substances (GOST R 55661-2013) of fuel samples were determined. The results of calculated and experimental studies on the heat of combustion are presented; ash content, the release of volatile products in the composition of fuels when they are co-fired. The saving of natural fuel and the prevented environmental damage to the atmosphere and soil during co-combustion of solid fuel compositions are calculated. A scheme has been developed for co-firing coal and biomass with subsequent complex purification of the resulting harmful gases by the ozone-ammonia method. CONCLUSION. Peat and sawdust, having a sufficiently high calorific value and low ash content, are a promising fuel, when combusted with coal, for boilers of low and medium power in areas with low gasification. The use of local fuel resources, alternative fuels will reduce the consumption of natural fossil fuels, increase the environmental safety of enterprises in the fuel and energy complex, small-scale energy, and ensure a sustainable growth of the gross national product.

The most significant technical solutions should be optimized using a technical and economic analysis, which reduces the cost of their implementation. Due to the fact that the diameter and height of the chimney depends on the gas velocity in the chimney, this parameter is decisive when carrying out a feasibility study. However, the existing methods and regulations in the Russian Federation concerning the construction and design of chimneys do not take into account all the necessary characteristics and parameters, for example, the economic component of determining the optimal gas velocity. PURPOSE of this article is to review foreign sources, in which consider similar issues and problems to take into account foreign experience in the development of a new methodology. METHODOLOGY. For the review, regulatory documents and scientific papers published in the most technically advanced countries were selected. RESULTS. In the course of analyzing the methodology for modeling the dispersion of impurities and calculating the height of the stack, it was concluded that, despite the large number of calculation models, the most accurate models are dispersion in air, based on meteorological data specific to a particular region. However, none of the considered methods for choosing the main dimensions of the stack is based on determining the optimal gas outlet rate based on the technical and economic analysis. The choice of the gas outlet rate is of a recommendatory nature and is mainly associated with the conditions for the formation of the initial section of the smoke plume and is not associated with the cost of the stack. The technique being developed in Russia makes it possible to take into account a wider range of chimney operating conditions, incl. and for the transitional phase to Green Energy, when the composition of combustion products will change depending on the proportion of hydrogen in the boiler fuel.

THE PURPOSE. paper show digital system for monitoring of single-phase earth faults on overhead power lines of 10 kV voltage in distribution power grids with an isolated neutral mode. METHODS. Digital system analyze frequency and amplitude of higher harmonics of voltage and current. The digital monitoring system includes the features of technical solutions for the selection of higher harmonics. RESULTS. Simultaneously, the paper shows the layout solutions for connecting a monitoring system to the control circuits on the10 kV side of 110/10 kV voltage substation. Software implemented for the far monitoring of the power grids and can detect of various types of single-phase earth faults. CONCLUSION. Software base on the mathematical models, as well as taking into account the results of a series of full-scale experiments of modeling various types of single-phase earth faults in the distribution power grids. The main functionalities the developed software presented for the description of solutions. Paper show further directions of research of the diagnostics and monitoring of single-phase earth faults in distribution power grids with overhead power lines based on the analysis of higher harmonic components.

THE PURPOSE. Study of the load of 0.4 / 10kV transformer substations installed in the residential sector. Justify the need to update the norms of specific electrical loads for residential complexes. Calculate the electrical load of residential complexes using the current and updated standards with an assessment of the economic effect. METHODS. When fulfilling this goal, statistical and economic methods of analysis were used. RESULTS. The article describes the relevance of the topic, provides a rationale for the need to update the standard values of specific electrical loads. The calculation of the electrical load was carried out according to the methodology of the Association «Roselectromontazh» both for an apartment building and for the residential complex as a whole. The example shows the economic effect of updating the standard values for the city of St. Petersburg. CONCLUSION. The values of electrical load, calculated according to the methodology of the Roselectromontazh Association, will reduce the cost of building electrical networks during the construction of residential complexes, reduce electrical energy losses in distribution electrical networks of 0.4/10 kV, which will lead to a reduction in the cost of commercial and residential real estate. Approved in 2019 The republican standards of urban planning, in terms of the declared capacity based on the methodology of the Association «Roselectromontazh» are successfully applied in practice and have significantly reduced the costs for construction companies of the Republic of Tatarstan for the implementation of power supply of residential complexes.

THE PURPOSE. To investigate the existing methods of frequency control and their influence on the characteristics of the asynchronous motor, including the energy parameters. Consider new circuit solutions of the control type under study. Create a mathematical model of each of the methods of frequency control. To analyze the results obtained from the point of view of the behavior of mechanical, electromechanical and energy components. METHODS. When solving this problem, the method of computer simulation modeling, implemented by means of Matlab Simulink, was used. RESULTS. In this paper, various aspects of electric drive systems based on asynchronous motors with the use of cascade switching are studied and described, existing connection schemes for such systems are analyzed, and several new options with improved characteristics are proposed. A comparative analysis of various connection schemes is made, the most interesting results of such analysis are presented, and conclusions are drawn about the future prospects of certain circuit solutions.Electric drive systems were modeled in the Simulink MATLAB environment using software tools to demonstrate the operation parameters of the considered circuits. CONCLUSION. Various schemes for switching on the asynchronous motor in the Simulink Matlab environment were investigated. The results of the study revealed the potential usefulness of using a circuit with a transformer in the rotor circuit, as well as the construction of a multi-motor electric drive with a common transformer and a common frequency converter circuit. The efficiency of parallel connection of rotary circuits of a two-motor electric drive was demonstrated. The methods of returning the sliding energy to the network are also compared, and their effectiveness in a comparative analysis with the operation in the closed-loop rotor mode is demonstrated.

THE PURPOSE. Examine the problem of reliable functioning of small electric power fiscal metering locations (EPFML) based on unconventional instrument current and voltage converters (Rogowski coil and resistive divider). Identify the most severe environmental conditions in which EPFML can be operated. Conduct research into EPFML thermal condition in different grid operation modes, and also during high voltage testing. Determine the conditions in which heat emission at the resistor divider attains its maximum value. METHODS. To solve the problem, use was made of three-dimensional hybrid field and chain simulation models, calculated by the methods of finite elements and linear electric circuit theory. The developed simulation models enable research to be conducted not only in normal, but also emergency electric grid operation, during lightning and pulse surges, insulation testing, and in the presence of insolation. RESULTS. The article presents the results of research concerning the thermal condition of a 6 (10) kV automated electric power fiscal metering location. CONCLUSION. If a resistive divider is used as a primary voltage converter, maximum heat emission occurs in the event of intermittent single phase arc faults to earth in accordance with Petersen’s theory. The results of the conducted research show that an EPFML based on a resistive voltage divider should be calculated using simulated models, taking into account insolation and the daily pattern of changes in maximum ambient temperature.

THE PURPOSE. Consider the most pressing and important problems of parallel operation of generator sets as part of autonomous electrical complexes of modern sea vessels, such as the transition of diesel generator sets to reverse power mode and the existence of power exchange oscillations during parallel operation. Consider the possibility of improving the method for eliminating power exchange oscillations using maps of dependences of the amplitude of oscillations on the parameters of diesel generator sets. METHODS. When solving the problem, a mathematical model of an autonomous electrical complex was used, which allows to take into account the backlash clearances in the control loops of the rotation frequency of parallel diesel generator sets. RESULTS. A map of the dependence of the load angle on the backlash clearances was constructed. The complete identity of the maps of the dependence of the load angle on the backlash clearances and the maps of the dependence of the amplitude of the power exchange oscillations on the backlash gaps has been proved. In the criterion for determining the value of the amplitude of the power exchange oscillations, it is proposed to use the load angle of the generators instead of the envelope currents of the generators. CONCLUSION. The use of the load angle of parallel operating generators allows to increase the speed and accuracy of the unit for eliminating power exchange oscillations. The developed approach makes it possible to control the transition of generating sets to the reverse power mode and the appearance of power exchange oscillations based on measuring the load angles of the generators.