Autonomous Power Supply System Research Articles

Wind power plants functioning model in the power supply system

The system of complex energy supply of various objects is considered, existing problems in the field of wind power engineering are identified, those that leave complex energy supply using renewable energy sources are analyzed, and the quality of supplied energy is assessed by the efficiency factor. The structural model of wind power plant (HPU) functioning as a subsystem in the autonomous power supply system was considered separately. Methodological bases of designing in the form of structural scheme of methodology of development and creation of rotor HPU have been developed. All stages of designing and development of a wind power plant are analyzed.

Experimental Research of Thermal Processes in Hydrogen-Oxygen Air Heater for Autonomous Power Supply System

The results of experimental studies in hydrogen-oxygen air heater for autonomous power supply system are presented. As a result of studies, it was found that the use of a stepwise air supply scheme leads to the decrease in the formation of nitrogen oxides in a wide range of operation parameters. The separation of heating and air mixing into three zones ensured a decrease in the content of nitrogen oxides in the generated air down to 4 ppm. It was found that an increase in pressure in the combustion chamber leads to an increase in the completeness of hydrogen combustion and has practically no effect on the formation of nitrogen oxides. It is shown that nitrogen molecules directly enter the combustion zone with intensive oxidation, and to reduce the formation of nitrogen oxides, air must be supplied at a distance of at least 3 cooling zones in the combustion chamber.

The parameters of the off-grid power system with a biomass gasifier engine for the autonomous power supply of forest harvesters

The paper analyses the results of the simulation modelling of autonomous power supply system of forest electric drive harvesters. MATLAB with the use of dynamic modelling Simulink tools was employed for the simulation modelling. The modelled system incorporates gasifier for solid fuelwood, a heat engine, an electric generator, a battery, and electric drive engines for the mechanisms of a mobile wood chipper. The authors determined that the minimum 12 A h Battery is required to ensure the uninterrupted operation of an off-grid power system with a gasifier, a 300 kW heat engine and a 200 kW engine wood chipper. The model allows for measuring the system performance indicators in various operating modes. The specific consumption of fuelwood was 2.217 kg/kW h in the specified mode.

Design of energy efficient electrotechnical complexes with an autonomous electric supply system

Improving energy efficiency and reducing the costs of creating an autonomous power supply complex for an oil production enterprise is an urgent problem and requires a rational solution. At each stage of the electrical complex development of the oil production enterprise, the purpose is to increase energy efficiency in order to reduce the unit cost of electricity per unit of produced well fluid volume. The electrical complex energy efficiency assessment of the oil production enterprise can be determined by the classical methodology of the energy balance. The task of increasing the energy efficiency of the electrical complex with an autonomous power supply system is to ensure a minimum of fuel costs while maintaining current oil production. Two types of the electrical complex models are proposed: with an individual electricity source and a generation center based on individual diesel generators. A method for calculating the energy parameters of the electrical complex components with installations of different types of pumps is presented. In this case, the energy efficiency is improved due to joint deep and group reactive power compensation and power factor correction by reducing the harmonic components of the current. The electrical complex simulation of a submersible electric motor has been carried out in order to determine the values of voltage and current during switching processes. The autonomous power supply system modeling of an oil production enterprise in case of voltage losses and the simulation of diesel generators with a frequency deviation of the generated voltage during load surges was carried out.

PROSPECTS AND BACKGROUND INTRODUCTION OF AUTONOMOUS POWER SUPPLY SYSTEMS FOR AGRICULTURAL ENTERPRISES

The agro-industrial complex is one of the most stable in terms of revenue to the budget of intersectoral formations, in which significant amounts of electricity produced using fossil fuels, mainly imported, fuel resources are consumed for the implementation of production processes, which poses a threat to its effective functioning and makes in the research article. The purpose of the article is to assess the potential and determine promising methods of decentralized power supply for agro-industrial producers based on the analysis of modern technical and technological solutions in the field of electrical engineering and the synthesis of a promising scheme for a combined autonomous power supply system for agricultural enterprises. The article assessed the technical and technological capabilities for the use of autonomous electrical installations by small and medium-sized enterprises of the agricultural sector, operating on the principle of conversion of renewable sources, taking into account the natural and climatic potential of the Vinnytsia region. As a result of a comparative analysis of the operational characteristics of the known methods of accumulating electric energy, it was found that in the conditions of autonomous power supply of small and medium-sized agro-industrial enterprises due to the conversion of alternative energy sources, the most functionally and economically justified option is the use of energy storage systems based on flywheels with partial use of a backup unit lithium-ion batteries. Based on domestic and foreign experience, a promising scheme of a combined autonomous power supply system for small and medium agricultural enterprises was proposed and priority areas for further research were formed to improve the efficiency of such a system. The study of technical and technological prerequisites for the development of a combined system of autonomous power supply and its components was carried out using methods of analysis, generalization and a systematic approach. The potential advantages and effect of the proposed scheme implementation are based on the laws of development of technical and electric power systems.

Development of a vector control system of the semiconductor converter, which will provide a polyharmonic operating mode of a polyphase electric machine

A system for vector control of current in the circuit of a polyphase electric machine has been developed. For this, on the basis of the analysis of electromagnetic processes in a multiphase semiconductor converter of electrical energy, its discrete mathematical model was created, which takes into account the redistribution of electromagnetic energy by individual spatial harmonic components depending on the number of phases. Using this mathematical model and the scheme of injection of higher current harmonics, which provides a polyharmonic mode of operation of a semiconductor converter, a method for independent control of the spatial harmonic components of the input current of the converter has been developed. The formation in each of the phases of polyharmonic currents, conjugated in shape and phase with the voltage supplying the converter, is carried out by means of control actions in the form of voltage vectors of a semiconductor switch, the implementation of which is carried out by the method of multiphase space-vector modulation. To check the developed provisions, a simulation model of a nine-phase semiconductor converter of electrical energy with a vector control system was created. The results of the study of the model confirmed the adequacy of the developed technical solutions, the use of which will ensure the most complete realization of the own advantages of a multiphase electric machine in order to generally improve the weight, size and energy indicators of the autonomous power supply system.

Магнитные системы бесконтактных регулируемых синхронных генераторов с основным магнитоэлектрическим возбуждением

The article is devoted to the search and research of ways to optimize magnetic systems of contactless synchronous generators with a capacity of 30–50 kVA used in Autonomous power supply systems for ground-based mobile objects. The main atten-tion is paid to electric generators with a combined excitation system, the air gap magnetic flux of which is created by the combined action of permanent magnets of the main inductor and an electromagnetic adjustment link necessary to maintain the constancy of the output voltage when the rotor speed and generator load change. Ac-cording to the authors, with an increase in the power of the source over 30–35 kVA, DC machines will be replaced by generators of this type. The article also describes a machine with a fundamentally new magnetic system, which contains elements of the design of electric machines with radial and axial flux. The proposed magnetic system, according to the authors, allows us to fully utilize the potential inherent in machines of both forms, improve the specific characteristics and, most importantly, maintain the highest technical reliability inherent in contactless Electrical Machines.

НАБЛИЖЕНА ЗАСТУПНА ЕЛЕКТРИЧНА СХЕМА СИНХРОННОГО ЯВНОПОЛЮСНОГО ГЕНЕРАТОРА ДЛЯ АНАЛІЗУ НАВАНТАЖУВАЛЬНИХ РЕЖИМІВ РОБОТИ АВТОНОМНИХ ВІТРО- ТА ГІДРОЕЛЕКТРИЧНИХ УСТАНОВОК

Синхронні явнополюсні генератори знаходять широке застосування в складі вітро- та гідроелектричних установок малої потужності. На сьогодні набуває актуальності задача застосування потужних автономних вітроелектричних установок з синхронними генераторами для накопичення частини генерованої ними енергії на гідроакумулювальних електростанціях. Розроблення раціональних схемо-технічних рішень реалізації даної технології для багатоагрегатних вітроелектростанцій потребує аналізу навантажувальних режимів роботи всіх складових в широкому діапазоні робочих швидкостей вітру і частоти обертання. Ефективне моделювання та проведення розрахункових досліджень перебігу електромеханічних процесів в даних системах може бути реалізовано шляхом застосування заступних електричних схем генераторів та двигунів, проте для явнополюсного синхронного генератора неможливо побудувати точну заступну електричну схему для електрорушійної сили обмотки якоря. В рамках цього дослідження розроблено наближену заступну електричну схему фази явнополюсного синхронного генератора та виконано оцінку можливих похибок результатів розрахунку параметрів навантажувального режиму схеми за різних значень частоти обертання ротора. Схема базується на послідовному ввімкненні активного опору обмотки якоря та індуктивних опорів розсіювання і поперекової реакції якоря, а також індуктивного опору, зумовленого сумісною дією поперекової та повздовжньої реакцій якоря. Очікувані похибки визначення розрахункових параметрів напруги споживачів автономної системи електроживлення на основі вітро- та гідроелектричних установок з синхронними явнополюсними генераторами за використання розробленої заступної електричної схеми не перевищують 2,5% по модулю та 1,5 електричних градусів по фазі для довільного значення частоти обертання ротора генератора в діапазоні 0,6...1,2 номінального значення. Застосування розробленої заступної електричної схеми явнополюсного синхронного генератора надає можливості проведення автоматизованих багатоваріантних розрахункових досліджень електромеханічних перехідних процесів в системах електроживлення на основі вітро- та гідроелектричних установок з урахуванням пульсацій швидкості вітру, зміни витрат та напорів води, зміни навантаження. Бібл. 24, табл. 3, рис. 3.

General principles of expanding the speed range of operation of autonomous power supply systems for passenger cars

Authors address the issues of expanding the speed range for operation of autonomous power supply systems for air-conditioned passenger cars. For the first time in the domestic car construction, the issue of reducing the minimum start-up speed of a generator-drive unit arose when the passenger fleet of the Sakhalin Railway was renewed, where the speed of passenger cars is much lower than the overall network speed. Research carried out by CJSC SO TIV and JSC TVZ has shown that the use of V-belts in the modernization of the textropic-reduction-cardan drive allows solving this problem. Kinematic diagram of the drive was adopted without changes, but with the replacement of the V-belts C (B)-2360T with new narrow belts XPC-2360 without working surface wrap and with a formed tooth on the lower base. In the tensioner, the main spring with a stiffness of 75 N/mm was replaced with a spring of increased stiffness (100 N/mm). The main change was the replacement of the 2GV003 generator with a 2GV008 low-speed generator, which has a minimum rotation at full power (700 rpm). This modernization of the drive made it possible to turn on the generator 2GV008 at rated power, starting at a speed of 30 km/h. The article sets the task of expanding the speed range of operation of the EV-7 and EV-10 autonomous power supply systems for cars without air conditioning. It is solved by forcing the excitation of the generators. Analysis of modern systems of autonomous power supply of passenger cars showed that the expansion of the speed range of its operation can be achieved in three ways: • raising the gear ratio of the gearbox to ensure it is switched on to the nominal mode at a carriage speed of 15 - 20 km/h without changing the parameters of the generator and the entire system of autonomous power supply; • modernization of the electrical equipment complex for passenger cars to ensure the operation of the main power consumers and charge the battery while driving at low speeds (over 18 km/h) without changing the mechanical parameters and composition of the serial generator-drive unit; • modernization of the generator in order to reduce its turnon revolutions to the power required to provide the main power consumers without changing the mechanical parameters of the drive. All three methods have its advantages and disadvantages, the choice of any of them is determined by the technical requirements for a specific car model.

Spectral Analysis of Output Voltages and Currents as a Criterion for Technical Diagnostics of Synchronous Generators of Ship Diesel Engine

Abstract Diesel generator sets (DGU) are very widely used in autonomous power supply systems. An example is marine power plants, diesel locomotives with electric power transmission, uninterruptible power supply units, etc. The power of ship DGUs reaches 2–6 or more MW in one unit. The number of units on ships can be different, but, as a rule, at least two. In this paper, we propose a method of monitoring the dynamic electromechanical system “diesel synchronous generator”. The method aims at using a synchronous generator machine as a multifunctional accurate and sensitive sensor for diagnostic parameters of the electromechanical system. The proposed method of technical diagnostics is based on continuous monitoring of non-uniformity of diesel torque, fluctuations in the instantaneous angular velocity and instantaneous angular acceleration of the diesel crankshaft. These data are the results of a spectral analysis of stator currents and voltages of a synchronous generator.

Influence of Renewable Energy on Energy Security of Decentralized Electricity Systems

The article offers evaluation of the potential of renewable energy in improving the energy security of decentralized power supply systems and solving the problems of their development. The authors proposed a complex of indicative indicators with introduction of renewable energy sources as part of separate indicators, which allows us to research the energy security problems of regional decentralized energy systems of power supply. In the rationale for each indicator the place of renewable energy sources in aspects of resource security, the level of reliability of autonomous power supply systems, environmental and other positions of energy security have been shown. The proposed module of indicators with introduction of renewable energy includes a science-based list of criteria, methods and tools for their evaluation with the focus of measures to ensure energy security by means of integrating into autonomous power supply systems of renewable energy plants. The article traces the matching of the proposed approaches with the place of renewable energy in strategic planning documents in the national security of the Russian Federation

A Mathematical Description of Dynamic Modes of Operation of the Autonomous Power Supply System in the Presence of Nonlinear Elements in Its Composition

Methodological provisions for studying transient processes in the systems of autonomous power supply with a chemical current source are considered in the presence of nonlinear elements in the voltage control system. The method of statistical linearization has been used to study the dynamics of this system. The equivalent circuit of the system and the mathematical apparatus that allows one to determine the statistical amplification coefficients have been suggested. The stationary random process to change power consumption from the power supply is represented as a mathematical expectation and a decreasing correlation function, and the electrochemical cell in the transition mode at the section a slow change in the output coordinate is considered as an aperiodic link of the first order. Two methods to solve the obtained system of equations, which describes a change in the voltage at output of an electrochemical cell, have been suggested: the method of successive approximations and the graphical method. An example of calculation of the transient process of an autonomous power supply system with an electrochemical cell has been considered.

Use of gasifier-based electric power stations for improving the economy of autonomous power supply systems in Russia

In Russia, significant amounts of waste of logging and woodworking that can be used for energy production are generated. In this paper, we consider an autonomous power supply system, including a wood biomass gasification power plant (BGPP), a diesel power plant (DPP), one or several wind turbines (WT), and electricity consumers with their load schedule. The mathematical formulation of the problem of optimizing the structure and modes of operation of the power supply system is reduced to minimizing the objective function with a number of additional constrains. The objective function is equal to total discounted costs for the construction and operation of the system or the cost of electricity produced. Additional constrains are balances for power, primary, secondary and final energy. The power supply system was modeled for different values of diesel and wood fuels prices, average long-term wind speed, technical and economic indicators of power plants. According to the results of calculations, the zones of technologies efficiency and the cost of electricity produced are determined. It is shown that biomass gasification power plants with gas storage tanks are much more economical than diesel power plants and can displace them at current diesel fuel prices. In areas with high average annual wind speeds, biomass gasification power plants should be used in conjunction with wind turbines.

Combined Energy Supply for Sixty-Two Heliostats of the Big Solar Furnace

The article discusses the issues of increasing the reliability of regular, systematic, continuous operation during the day of 62 heliostats in the sun tracking mode by connecting to the centralized power network an additional autonomous power supply system with a power of 15 kW, consisting of a standard gasoline engine with an inverter and а solar Fresnel mirror-concentrating system with a steam turbine generator that produces electric power

Modular aggregation functions performed by static inverters in autonomous power supply systems

Static power inverters (SPI) are important functional elements to provide efficiency and reliability for autonomous power supply systems (APSS). The paper proposes to improve technical and economic characteristics of APSS through modular aggregation functions and reduced number of power electronic devices constituting SPIs. The paper provides a generalized SPC topology and insights into its performance. It deals with some electric schematic diagrams for a controlled rectifier and a three-phase modular inverter, a three-phase voltage inverter based on two single-phase inverters and a single-phase-three-phase rotating-field transformer, as well as a chain diagram for a universal modular static power inverter. It is shown that modular aggregation functions of APSS static power inverters will improve reliability through back-up operations performed by the main functional units and assemblies, and reduce time intervals for their maintenance and repair. The efficiency of autonomous systems will be advanced due to a decrease in the total number of power electronic devices constituting SPIs. In addition, the level of electromagnetic interference generated by these devices will decrease. A significant technical and economic effect will be achieved by using universal modular static inverters in the APS systems, capable of passing energy flows back and forth in both directions and operating in various modes.

Electromagnetic compatibility of functional elements of autonomous power supply systems

Currently, static power converters are used as part of autonomous power supply systems. System developers deal with electromagnetic compatibility of sources, converters and consumers of electricity, due to the switching of power electronic devices that create electromagnetic interference and deteriorate quality of electricity and cause malfunction of electrical equipment. The article discusses causes of electromagnetic interference and ways to eliminate it. The noise level is reduced due to the use of single-phase-three-phase transformers with a rotating magnetic field and universal static converters as part of static converters, which can reduce the number of power electronic devices in the autonomous system - sources of electromagnetic interference. The basic rules of installation of equipment that reduces the electromagnetic interference were analyzed. An effective method for reducing the electromagnetic interference is application of passive reactive filters at the input and output of static converters, as well as protection of equipment from external electromagnetic fields by electrostatic shields. The methods for reducing the electromagnetic interference will increase the level of electromagnetic compatibility of equipment used as part of the autonomous power supply system.

The methodology for design of autonomous power supply system of oil producing company optimized on length and number of generation centers

Improving energy efficiency and reducing the cost of creating an electrical complex of autonomous power supply for an oil-producing enterprise is an urgent problem and requires a rational solution. The goal is the construction of energy-efficient electrical systems of autonomous power supply for oil-producing enterprises, leading to a reduction in the unit cost of electricity per unit of production. A methodology for constructing an autonomous power supply system for an oil producing enterprise, optimized in length and number of generation centers is present. The results presented in the work were obtained using methods of the theory of electric and magnetic circuits, theory of electric drive, methods of optimization of power supply systems, methods of mathematical and computer modeling. The configuration of the power supply system of oil producing enterprises and the efficiency of its work is analyze. To test the efficiency of the methodology, the power supply system of an oil producing enterprise is simulate in the RTDS software package. The results of the work were introduced and used in the creation of energy-efficient electrical systems for autonomous power supply to oil-producing enterprises based on autonomous diesel generators and optimized by the length of power lines and the number of generation centers. Implementation of the results of the work allows reducing the specific energy consumption per unit of extracted products and reducing the cost of building an energy-efficient electrical complex of autonomous power supply for oil-producing enterprises.

Использование ветродизельной электростанции как основного источника электроснабжения нефтеперекачивающей станции

For electrification of decentralized energy consumption facilities, as a rule, constructed an autonomous diesel power station, the operation of which involves the use of diesel fuel mainly to start the unit, and the rest of the time the diesel generator sets operate on treated oil. To reduce fuel consumption (treated oil) and reduce the load on diesel generators, it is proposed to use as the main power source for oil pumping stations, located in regions with high wind energy potential – an autonomous hybrid power-supply system – wind-diesel power station with a parallel operation of the wind and diesel power station. The article provides an operation scheme of a wind-diesel power station. In case when there is no possibility to place diesel generator sets of the equivalentcapacity in the powerhouse hall, then the article describes the optimal calculation algorithm for power distribution between diesel generator sets with different capacity, based on solving simultaneous equations by using the Lagrange multiplier method. The article also provides a practical example of the algorithm.

Identification of parameters for the hybrid electrical energy storage system in autonomous power system

The article describes the approach to the selection of parameters of a hybrid electrical energy storage system (EESS) based on supercapacitors (SC) and lithium ion battery (LIB) for an autonomous power station with a diesel generator set (DGS). The calculations of transients in an autonomous power supply system with an abruptly variable load and participation of a hybrid EESS. The procedure of determining the share of participation in the energy exchange of storage subsystems based on LIB and SC is presented.

FEASIBILITY ANALYSIS OF A RENEWABLE AUTONOMOUS POWER SUPPLY SYSTEM AT A COASTAL AREA IN INDONESIA

The Indonesian government program in providing solutions for electrical energy distribution problems to get to remote or isolated areas is to optimize the potential of renewable energy in an area. The combination of conventional power plants (diesel generators) with renewable energy (photovoltaic and wind turbine) power plants is expected to solve the problem of electricity service in isolated areas in southern Tulungagung regency, namely residential area in Brumbun Beach. The existence of government assistance in the form of solar panels distributed to each family head still can not optimize the utilization of electrical energy for 24 hours in a day, this is because the generation of diesel generators and solar panels are done separately. This research focuses on the design and analysis of a renewable autonomous power supply system which consists of a centralized solar-powered diesel generator (solar panel – a wind turbine – diesel generator) systems using HOMER software. This software is in addition to being used to create designs, is also capable of performing the most optimal system design evaluation by sorting based on overall cost, basic electricity tariff, and carbon dioxide gas emissions. The research from the design of four power plant configurations shows that the use of 10 kW diesel generators, 8 kW solar panels, and 6 kW wind turbines is the best solution, from the combination of the three energy sources shows the net present cost (NPC) value of US $ 44,680, Cost of Energy (COE) of 0.268 kWh / $, CO2 emissions of 1,077 kg/year, and diesel generator use only 54 minutes a day.Keywords: Cost of Energy, Hybrid Power Generation, HOMER, Net Present Cost, Renewable EnergyJEL Classifications: C63, C88, Q42DOI: https://doi.org/10.32479/ijeep.9066