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Power engineering: research, equipment, technology

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Vol 23, No 3 (2021)
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ELECTRICAL ENGINEERING

3-13 539
Abstract

THE PURPOSE. To develop an algorithm for estimating electricity losses, taking into account the influencing factors in the main circuits of shop power supply. To study the influence of the main parameters of electrical equipment on the equivalent resistance of the distribution busbar. METHODS. We use element-by-element methods for calculating active power losses using equivalent resistance on the example of a section of the main circuit of the shop network. Factors affecting the equivalent busbar resistance, such as the root-mean-square load factor, the load graph shape factor, the resistance of the contact connections of switching devices, and the ambient temperature, are investigated. RESULTS. The values of the resistances of the branch lines from the busbar are calculated taking into account the heating of the conductors and the resistances of the circuit breakers and magnetic starters installed on the line during the element-by-element calculation. The relations in the value of the equivalent resistance of the busbar to the values of the resistances of the contact connections of low-voltage electrical devices installed on the branch lines from the busbar, the values of the resistances of the branch lines taking into account heating, the value of the resistance of the busbar and the values of the resistance due to the heating of the busbar are revealed. CONCLUSIONS. The share of each of the studied parameters in the value of the equivalent resistance of the busbar is determined. The value of the relative error in determining the equivalent resistance of the busbar depending on the number of connected electric receivers and taking into account the studied parameters is calculated. The estimation of the value of the electricity losses of the section of the main scheme of the shop network was carried out in accordance with the daily schedule of the load of consumers.

14-33 542
Abstract

THE PURPOSE. To consider the technologies for the manufacture of permanent magnets and their areas of application. To identify global trends in the change in demand for rare earth metals. To study the prospects for the development of additive production of polymer magnetic materials. METHODS. When studying this issue, an analysis of a wide range of domestic and foreign sources of scientific literature was used. RESULTS. Prospective technologies for the additive production of polymer magnetic materials for a variety of applications have been studied. The need to establish a relationship between the properties of the starting material, the diameters of the extrusion nozzles, the printing parameters, as well as the mechanical and functional properties of the resulting magnets is indicated. CONCLUSION. This article provides a comprehensive overview of recent advances in the application of additive manufacturing, topology optimization and their integration for electrical machines and their magnetic components. Additive manufacturing technologies such as 3D printing, BAAM - the technology has potential advantages such as lower production costs, elimination of the need to make molds, the ability to create permanent magnets with field profiles and magnetic properties that cannot be obtained using modern methods. The considered technologies can be used as a tool in the design and development of innovative magnets for electric motors, which will make the most of the magnetic flux and thereby increase the energy efficiency of drive systems. This will allow rapid prototyping of parts and reduce the time to market for new products.

34-46 681
Abstract

THE PURPOSE. To consider and analyze the definitions of the concepts "configuration of the electrical grid", "control of the configuration of the electrical grid ", "parameters of the configuration of the electrical grid ". To justify the need to manage the configuration of electrical grid, describe the principles and methods of managing the configuration of the electrical grid. To demonstrate the implementation of the principles of managing the configuration of the electrical grid on the example of an electrical grid with a nominal voltage of 0.4 kV with the use of proprietary technical configuration management tools. METHODS. Based on the literature review, the study identified the wording of key concepts, such as" configuration of the electrical grid"," management of the electrical grid configuration", "parameters of the electrical grid configuration". Methods of managing the configuration of the electrical grid are shown. The principles of electrical grid configuration management proposed by the authors are considered, which include observability, manageability, segmentability, flexibility of the electrical grid configuration, equipment intellectualization, and integration into the economy. The essence of each of the management principles is revealed and the effects of their implementation are shown. The effects of implementing the configuration management principles are to reduce the number of power supply interruptions and reduce the time of power supply interruptions to consumers, mismatch the quality parameters of the electricity supplied to them, as well as to increase the availability of electricity infrastructure. The rationale for the need to manage the configuration of electrical grid is given. Within the framework of the conducted research, the method of system analysis, methods of comparisons and analogies, and expert assessments were used. RESULTS. On the example of the scheme of power supply to consumers at a voltage of 0.4 kV, the implementation of the principles of control of the configuration of electrical grid with the use of proprietary technical means – multi-contact switching systems, input-accounting-distribution devices integrated into the monitoring systems of the parameters of the operating modes of electrical grid and other devices is illustrated. CONCLUSION. The implementation of the principles of configuration management of electrical grid allows to increase the efficiency of power supply systems for consumers and at the same time causes the need to develop new technical means of automation and monitoring of parameters of operating modes of electrical grids.

47-57 612
Abstract

THE PURPOSE. To determine the composition of electricity consumers in apartment buildings. To analyze the power consumption of organizations located on the first two floors of apartment buildings. To justify the need to update the standards for electrical loads for public premises built into residential buildings. METHODS. Information on electricity consumption was received by automated electricity metering system from smart meters installed directly at consumers. To achieve this goal, statistical methods for analyzing energy consumption were used. RESULTS. The article describes the relevance of the topic, provides a rationale for adjusting the normative values of specific electrical loads for public premises built into residential buildings. The percentage of consumer groups is shown on the example of several apartment buildings. The annual specific average monthly graphs of electricity consumption are presented: shops, offices, pharmacies, restaurants. CONCLUSION. In an effort to increase the level of comfort, developers are interested in developing the infrastructure of the facilities, mainly for this, they use ground and first floors, in which retail and office areas are most often located. Research by the Roselectromontazh Association has shown that to determine the electrical load of non-residential commercial premises, one has to use one averaged value due to the constant change in the purpose of premises and the complexity of determining the occupied area.

58-69 660
Abstract

THE PURPOSE. To analyze scenarios for the development of the energy complex of one of the regions of the North-East of Russia for the period up to 2030 with a target vision until 2050. This will require an analysis of the current state of the energy complex; show the latest changes in the power supply system; propose promising areas for the transfer of electricity. METHODS. To assess the current state of the electric power industry, from the point of view of the most efficient use of natural energy resources and the potential of the energy sector of the economy, methods of collecting and processing statistical data were applied. For the technical assessment of the state of electric power facilities, analytical and logical- probabilistic methods for determining reliability were applied. To predict energy consumption, mathematical modeling methods were used with the construction of approximating polynomials. RESULTS. The article evaluates the strategic and moderate scenarios for the development of the energy sector of the Republic of Sakha (Yakutia) in modern conditions, taking into account the increase in the energy efficiency of the region's economy. The indicators of electricity consumption throughout the republic, the Western Energy District and the decentralized power supply zone were subject to assessment. Long-term forecasts made do not confirm the development of events according to a more stringent strategic scenario. At the same time, the results for the moderate scenario are fully correlated with both the current state of the energy sector and the prospects for its development. CONCLUSION. Analysis of the current state and assessment of scenarios for the development of the energy sector of the republic's economy showed an increase in the reliability of power supply systems when organizing a "ring" in the Western Energy District; increase in useful electricity consumption by 2030; increase in electricity production; changes in the structure of electricity production.

70-79 591
Abstract

Permanent magnet synchronous motors (PMSM) are widely used in various fields of application of electric drives of industrial enterprises. For each application of the electric drive, it is necessary to accept technical requirements, such as the maximum torque of the electric motor and the fulfillment of the required conditions for the strength characteristics of the rotor and stator.

PMSM has a number of advantages over other types of engines. Asynchronous motors have developed resource rational energy efficiency, while synchronous motors are more energy efficient without modifications. PMSM have smaller weight and size parameters, which allows them to be used in a wider field of application, for example, in household appliances, robots and many other drives.

TARGET. The aim is to develop a methodology for topological complex optimization of the engine design, based on a genetic algorithm.

METHODS. The genetic algorithm is more accurate than traditional analytical methods, the method used in the analysis of AC machines, takes less time than the usual trial and error design procedure based on the finite element method. The main optimization criterion is an increase in torque while maintaining the mass of the most expensive material (permanent magnets). This feature is important for the manufacture of a designed engine in production.

RESULTS. A program has been written in Python, which made it possible to carry out a comprehensive topological optimization for the engine under consideration.

CONCLUSION. Topological optimization based on the method of modifying the rotor design using a genetic algorithm with the additions necessary for correct operation with synchronous motors is presented.

80-89 765
Abstract

THE PURPOSE. The main purpose of the work is a comprehensive study of external influences that affect the operational reliability of low-voltage asynchronous motors. Attention is focused on the evaluation of the operational reliability of electric motors, the systematization of their operating conditions, with the simultaneous impact of a group of operational factors. Among these factors that are subject to detailed analysis, we will highlight the following: the asymmetry of the stress and its duration, loading of the motor, the temperature of the environment. In this regard, it becomes obvious that the task of improving the operational reliability of low-voltage asynchronous electric motors depends on a qualitative study of the quantitative values of external influencing factors in various operating modes of electric motors. METHODS. The tool for implementing this task is a visual and effective simulation tool Simulink interactive programming environment Matlab. RESULTS. The research was performed on an asynchronous electric motor with a short-circuited rotor AIR160S8 with PH = 7,5 kW, rated speed n = 1500 rpm. The physical processes of the electric motor under study were modeled by changing the following parameters: the coefficient of stress asymmetry in the reverse sequence (K2U), the load on the motor shaft (Kz), the ambient temperature (tocr), and the duration of stress asymmetry in the reverse sequence (T). Based on the obtained simulation results, groups of planes of the studied quantities are constructed. CONCLUSION. A set of studies performed using the Matlab software package allowed us to estimate the limits of acceptable values of external factors and identify the area of acceptable operation of asynchronous motors. The analysis and discussion of the research results were carried out, and measures were proposed to improve the operational reliability of asynchronous electric motors.

90-102 514
Abstract

PURPOSE. The purpose of this article is to study the search for ways to reduce energy consumption and develop methods for increasing the energy efficiency of water utilities. The studies reflected in the article are based on the results of an energy survey of a water utility in the city of Gomel (Republic of Belarus), one of the tasks of which is the search for reserves for saving fuel and energy resources by reducing technological water consumption. The article presents the results of research on the example of two water intakes «Iput» and «Sozh». METHODS. When solving the problem, the methods of mathematical statistics were used, including the method of analysis of variance to assess the significance of the effect of water flushing on reducing the iron content. RESULTS. The article discusses possible ways to reduce energy costs by reducing technological water consumption, which are used to flush filtering structures. The main activities are the following: changing the filter flushing schedule with increasing the filter cycle; the use of water-air flushing; reuse of wash water. The article formulates a hypothesis: filter flushing leads to a decrease in the iron content in the water, i.e. improving the quality of cleaning. CONCLUSION. An increase in the energy efficiency of water intakes, along with measures to modernize and optimize the operation of pumping equipment, is achieved by saving water resources and, accordingly, the cost of electricity for their extraction, which is necessary when flushing the filter materials of the deferrization station. The assumption about a possible increase in the filtration cycle was the lack of significance of the influence of washing on the decrease in the iron content, which indicated the presence of a significant reserve of the washing cycle. The use of combined water and air flushing contributes to a significant reduction in both technological water consumption (40.1%) and electricity consumption (38.8%). The energy saving potential due to the reduction of technological energy consumption for lifting water for the purpose of flushing reached 89857 kWh / year for the studied water intake.

103-115 615
Abstract

THE PURPOSE. To describe the use of ABC and HML-methods for predicting the volume of emergency stock for main electrical equipment accessory parts. To describe the content of the methods, consider the problems and complexity of use. To propose an algorithm constructing a new method for forming an emergency stock based on the statistical data of an electric power company. METHODS. Various practical tasks can arise in electric power company. We have determined the most effective method for solving them using a numerical experiment. The highest efficiency of the ABC method is shown. The results of statistical processing will help to improve forecast precision using the ABC-method. RESULTS. The complex of statistical data and ABC-analysis showed high efficiency in short-term forecasting of electrical equipment components emergency stocks. Authors found that HML-analysis provides less precision in predicting the requirement of equipment. CONCLUSION. The ABC method is the most promising for implementation the specific task. The use of the method helps to accurately predict emergency stocks of company electrical equipment. The HML-method does not allow to precision planing the amount of required equipment.

116-126 712
Abstract

THE PURPOSE. In controlled AC drives used on continuous-action mechanisms, which include conveyors, conveyors, cranes, the most widespread are asynchronous motors with a phase rotor, controlled mainly along the rotor circuit using various regulators with low energy efficiency. To improve the energy efficiency of an electric drive based on ADFR, it is proposed to develop a control system that combines the principles of frequency control of the motor along the stator circuit and powering the rotor circuit with constant voltage, which allows the electric drive to be considered synchronized. METHODS. The presence of a DC link in the frequency converter makes it possible in principle to connect the rotor winding in series to this link. However, in order to ensure the frequency principle of regulating the output characteristics of the electric drive, it will be necessary to regulate the rectified current at the input of the inverter and, accordingly, in the rotor windings, which will require a significant change in the standard control system of the frequency converter. The use of an additional adjustable switch in the DC link is proposed. RESULTS. The study of the proposed non-standard control system for a frequency asynchronous synchronized electric drive was carried out by the method of simulation modeling in the Matlab Simulink software package. CONCLUSION. A control system for a frequency asynchronous synchronized electric drive has been developed and investigated on a computer model. A correction system is proposed that allows maintaining a constant value of the load angle in the starting mode. The scalar system of relay frequency control of the electric drive is supplemented with vector correction of the variables, which makes it possible to continuously provide the necessary mutual orientation of the stator current vectors and the rotor flux linkage.

127-139 737
Abstract

TARGET. The purpose of this work is to develop a method for diagnostics of equipment of sucker rod pumping units (SRPU) during operation according to the parameters of the wattmetrogram. A wattmetering module is used as a measuring element, the developed software in the MatLab software package serves as a tool for processing vibration signals. The technical condition of the sucker rod pumping unit is analyzed by the parameters of the wattmetrogram and the amplitude spectra of the object under study, formed using the fast Fourier transform procedure in the MatLab software environment.

METHODS. The wattmetering method allows you to control the sucker rod-pumping unit during its operation under voltage. This control method is highly accurate, sensitive to developing defects, and allows the use of computer technologies for signal processing and analysis.

RESULTS. The wattmetering method is fully disclosed. The construction of the spectrum is considered. The relationship between the wattmetrogram and the dynamogram has been established. The removal and evaluation of experimental data from the operating sucker-rod pumping unit during its operation was carried out. A wattmetrogram and a dynamogram were built, a spectrum was also built, which showed the presence of defects in this installation.

CONCLUSION. This method of wattmetering with the MatLab software allows you to monitor the technical condition of the sucker rod pumping unit according to the amplitude-frequency characteristics of the wattmetrogram parameters.

140-153 536
Abstract

TARGET. The purpose of this work is to develop a non-contact laser control and measuring complex (LCMC) for vibration control of the level of pressing of windings and magnetic circuit of a power transformer. A laser vibrometer is used as a measuring element, the developed software in the LabVIEW graphical programming environment serves as a tool for processing vibration signals. The technical condition of the power transformer is analyzed by the amplitude spectra of the vibration of the tank of the transformer under study, formed using the fast Fourier transform algorithm in the LabVIEW software.

METHODS. The vibration control method makes it possible to control a power transformer during its operation under voltage, which makes it possible to move from a planned system of transformer repairs to a system for taking out for repair according to the current technical condition.

RESULTS. The developed LCMC allows to carry out non-contact measurements of vibration parameters of a power transformer under voltage and to establish the current level of pressing of windings and magnetic circuit.

CONCLUSION. The developed LCMC with software allows contactless control of the technical condition of the magnetic circuit and the windings of the power transformer according to the amplitude-frequency characteristics of the vibration parameters, as well as the use of statistical methods for processing and analyzing signals received from the transformer.

154-167 543
Abstract

THE PURPOSE. To determine the number of reconstructed, newly installed and replaced 10 / 0.4 kV transformer substations, consider an improved technology for installing a "pillow" under the foundation of a kiosk-type 10 / 0.4 kV transformer substation and determine the time spent on its installation. METHODS. The article presents an analysis of data on the number of reconstructed, newly installed and replaced 10 / 0.4 kV transformer substations, an algorithm for installing an improved "pillow" under the foundation of a 10 / 0.4 kV kiosk-type transformer substation. RESULTS. In the course of the experiment on the installation of an improved "pillow" under the foundation of the CTS, the time of work was determined. The total time spent on the construction of an improved "pillow" under the foundation of a kiosk-type CTS was 580 minutes, which is just over 9.5 hours. Also the standardized time of work during the installation of an improved "pillow" under the foundation of a kiosk-type CTS Also, the standardized time for performing work during the installation of an improved "pillow" under the foundation of a kiosk- type package transformer substation has been proposed. CONCLUSIONS. The use of the data presented in the article on the number of reconstructed, newly installed and replaced 10 / 0.4 kV transformer substations will allow scientists and specialists to develop and propose new methods of reconstruction and construction technologies for various transformer substations, as well as determine the economic efficiency of new foundations for transformer substations. The technology of kiosk-type CTS foundation installation described in the article will allow not only to increase the operational characteristics of the CTS, but also ensure the fire safety of the installed equipment. The technical solution specified in the article can be used during the reconstruction and construction of a 10 / 0.4 kV kiosk-type package transformer substation. The proposed algorithm for mounting an improved "pillow" under the foundation of a kiosk-type package transformer substation is universal, since it can be used at a package transformer substation of various capacities.

168-180 718
Abstract

THE PURPOSE. To justify the need to use an arc breakdown protection device (ABPD) in electrical networks up to 0.4 kV, in order to reduce the number of fires. To analyze the existing types of damage, compare the protection devices against various types of damage in electrical networks up to 0.4 kV. To consider the requirements for ABPD, as well as the main characteristics of protection devices and types of execution. To determine the area of application of the ABPD in electrical installations for various purposes. METHODS. To solve the problems associated with the peculiarities of the arc processes in various electrical circuits and the lack of criteria for many key parameters in terms of the requirements and applicability of the ABPD, it was proposed to conduct a series of tests for specific network parameters in order to understand whether a case can really take place in the current power system when ABPD will not work properly. RESULTS. A test bench has been developed for testing the protection devices against arc breakdown and spark gaps for the effectiveness of operation for specific network conditions, instructions for its operation are given. CONCLUSION. It has been established that a sequential arc breakdown can only switch off an arc breakdown protection device (ABPD) and, accordingly, increase the safety of operation of electrical networks up to 0.4 kV in order to reduce fires caused by violation of the rules for the design and operation of electrical equipment. The proposed device for testing protection devices against arc breakdown and spark gaps allows you to control the fact of mandatory operation of the ultrasonic detector for a certain time and formulate the requirements necessary for the design of power grids.

181-193 647
Abstract

PURPOSE. To consider the problems of modeling the processes of run-out, self-starting of a group of asynchronous electric motors (AM) in case of short-term power outages (NEC) and voltage drops in external short circuits (SC), convenient for programming and practical use. To establish the integral reaction of the AM group during self-start to the disturbing effect, taking into account their characteristics and duration to establish the permissible limit values of the NEC. To develop an algorithm for the transient process of self-starting of the AM group when using matrix and vector data representation when solving the basic equation of the rotor motion and its computer implementation. METHODS. When solving the problem, the following methods were used: successive approximations when solving the basic electromechanical equation, taking into account electromagnetic transient processes; Gauss-Seidel method with accelerating the convergence of the iterative process when solving the equations of the parameters of the regime; method of nodal stresses. The algorithm is implemented in VBA and tested in Matlab Simulink. RESULTS. The article describes the relevance of the topic, considers a model of AM according to catalog data, an algorithm for self-starting a group of an AM with NEC and external short circuits, taking into account electromagnetic transient processes, which has high accuracy and is convenient for practical use. CONCLUSION. The use of asynchronous motor catalogs makes it possible not to carry out laborious preliminary calculations of the parameters of asynchronous motors. The application of the Gauss-Seidel method with acceleration of convergence provides a decrease in the number of iterations. Taking into account electromagnetic transients and the effect of displacement of the rotor current allows you to evaluate the mutual influence of motors and increase the accuracy of calculations. The use of the method of nodal voltages makes it possible to determine the residual voltage on the busbar section with AM, if at the first moment the motors are switched on to short circuit. The implementation of the algorithm in the VBA environment is convenient for practical use.

194-208 456
Abstract

OBJECT. The work is aimed at solving an important problem of increasing the economic efficiency, the level of resource saving and accident-free operation of the first rise section of the centralized water supply systems of small and medium-sized settlements. At the same time, the task is to minimize the cost of electricity associated with the excess performance of pumps, while ensuring the protection of the pipeline from freezing in conditions of negative ambient temperatures. METHODS. To solve this problem, an optimal method for controlling electric drives of first rise pumps at the request of the end user of water was developed, which differs from the existing ones by analyzing the state of the thermal parameters of the pipeline. The method is based on the calculation of control actions based on the water level in the storage reservoir or the water pressure in the pipeline UL and the water temperature at the end of the pipeline UT, followed by the calculation of the optimal pump supply setpoint, which is then maintained by the frequency control method. The Matlab® Simulink simulation model was used to determine the optimal laws for calculating control actions and evaluate the effectiveness of the proposed solutions. RESULTS. Based on the simulation results, it was found that it is advisable to use the PID law for calculating the control effect for the UL level, the PD law for the UT temperature, and the PI law for the flow rate. The parameters of the technological process and the level of power consumption in the control process were also evaluated. CONCLUSIONS. Studies of the proposed concept of managing the first rise section have shown high technical and economic efficiency, in particular, the savings in electricity consumption are estimated at about 22 % while ensuring the protection of the pipeline from freezing.

209-222 821
Abstract

THE PURPOSE. Due to the increase in the number of farms in the Devashtichsky district of the Sughd region of Tajikistan, over the past 3-4 years, a disproportionate distribution of electricity in the 0.4 kV network has been observed. Unbalance currents of phase loads in relation to asymmetric phase voltages at the terminals of consumers of a three-phase network cause additional losses of electricity, which can reach 21% of the standard losses. In the decree of the President of the Republic of Tajikistan dated May 10, 2009 No. 29 “On energy saving and reduction of electricity losses” it is indicated that there is a need to study the quality of electricity in rural 0.4 kV networks and its compliance with GOST 32144. 2013, as well as an assessment of losses electricity in its distribution structure is an important task in the field of rural electricity. METHODS. A single-line diagram of a 0.4 kV network with initial parameters, which were refined during the survey of the network, and the current loads of outgoing lines were investigated. Experimental studies of the quality of electricity and assessment of the level of losses in the low- voltage network were carried out using a complex measuring device «Energotester» PKE - A - C4. RESULTS. The studies allowed obtaining data on the daily consumption of electricity in individual outgoing lines, information on the characteristics of consumers, digital information (database) on indicators of the quality of electricity in low-voltage networks. CONCLUSIONS. It has been established that the main factors influencing the losses of electricity in low-voltage networks are: incommensurability of the power of transformers of transformers and consumers, uneven loading of individual phases, a significant effect of individual converters on the quality of energy. Measures are forecasted to reduce losses and improve the quality of electricity in low-voltage rural networks of 0.4 kV.



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