Supply Power Consumption Research Articles

Non-contact controlled voltage stabilizer for power supply of household consumers

The article discusses the principle of operation of an optoelectronic voltage relay for switching windings of a boost voltage transformer of a voltage stabilizer. Based on the simulation of the proposed optoelectronic contactless voltage stabilizer using the MATLAB R2014a program, it was determined that the change in the shape of the output voltage curve is close to a sinusoid and coincides with the results obtained by the experimental path. When modeling a voltage stabilizer, the structure of the circuit does not change, but the parameters of the resistor elements corresponding to the open or closed state of the semiconductor device at the time of switching the vents change. The characteristic of voltage changes “input-output” and the analysis of existing voltage stabilizers on the principle of “quality voltage” in rural areas

Features of calculations of consequences of failures of power supply in distribution networks with the monoconsumer of electric energy

Reliability of power supply of consumers is an important task in the process of transmission and distribution of electric energy. The paper proposes a method for assessing the consequences of power failures of monoconsumers of electric energy on the example of an oil company and an adjacent power grid company. The uniqueness of the developed technique lies in the possibility of reliable calculation of reliability of power supply of complex branched electric networks without taking into account the specific scheme of power supply. The accuracy of calculations is increased due to the use of data directly studied power system, taking into account the specifics and operating conditions of specific equipment, instead of the average information. Classification of failures on the main reasons in electric networks of the oilproducing enterprise of the far North that allowed to develop actions for increase of level of reliability of power supply is made.

Application of priority and delayqueuing system in non-stationary modes to determine the required number of repair personnel in rural distribution electric networks

The paper considers the possibility of using a queuing system to determine the required number of repair and maintenance personnel in the event of mass failures in rural distribution electric networks. In this case, the separation of requirements for restoring failures (requests) into priority and secondary is used. The multi-channel queuing system is used with two priority levels, with the delay of both priority requests and secondary requests. The algorithm has been developed for composing a system of differential equations describing a given queuing system. The system of differential equations is solved by numerical methods, and, using a specially developed algorithm, based on the results of the solution for a given point in time, the required number of repair personnel is estimated based on such parameters as the probability of queuing and the average waiting time of requests in the queue. The developed algorithms have been implemented in software; the necessary number of repair personnel has been calculated with their use, as well as on the basis of statistical data on failures in rural distribution electric networks. Assessment of the intensity of the flow of priority and secondary requests has been carried out by two methods. In the first method the data from the dispatcher’s record book or acts of investigation of technological disturbances have been used. Failures were divided by such parameters as reliability categories of power supply for cut-off consumers, volume of cut-off load and social significance of cut-off objects. In the second method, those requests that could be fixed by the forces of the field service teams were priority, the remaining requests were considered secondary.

Short-Term Load Forecasting Using Smart Meter Data: A Generalization Analysis

Short-term load forecasting ensures the efficient operation of power systems besides affording continuous power supply for energy consumers. Smart meters that are capable of providing detailed information on buildings energy consumption, open several doors of opportunity to short-term load forecasting at the individual building level. In the current paper, four machine learning methods have been employed to forecast the daily peak and hourly energy consumption of domestic buildings. The utilized models depend merely on buildings historical energy consumption and are evaluated on the profiles that were not previously trained on. It is evident that developing data-driven models lacking external information such as weather and building data are of great importance under the situations that the access to such information is limited or the computational procedures are costly. Moreover, the performance evaluation of the models on separated house profiles determines their generalization ability for unseen consumption profiles. The conducted experiments on the smart meter data of several UK houses demonstrated that if the models are fed with sufficient historical data, they can be generalized to a satisfactory level and produce quite accurate results even if they only use past consumption values as the predictor variables. Furthermore, among the four applied models, the ones based on deep learning and ensemble techniques, display better performance in predicting daily peak load consumption than those of others.

ПОВЫШЕНИЕ ПРОПУСКНОЙ СПОСОБНОСТИ РАСПРЕДЕЛИТЕЛЬНЫХ ЭЛЕКТРИЧЕСКИХ СЕТЕЙ С ВОЗОБНОВЛЯЕМЫМИ ИСТОЧНИКАМИ ЭНЕРГИИ ПУТЕМ ИХ РЕКОНФИГУРАЦИИ

Актуальность исследования обусловлена необходимостью разработки технических решений по повышению пропускной способности перспективных распределительных электрических сетей железных дорог с возобновляемыми источниками энергии в темпе процессов изменения спроса на электроэнергию. Цель: повышение пропускной способности перспективных распределительных электрических сетей железных дорог с возобновляемыми источниками энергии путем оптимальной реконфигурации электрических схем. Объекты: распределительные электрические сети, источники распределенной генерации активной и реактивной мощности, методы оптимизации для решения задач в электроэнергетике, повышение пропускной способности электрической сети. Методы: оптимизационная задача решалась методом ветвей и границ, имитационное моделирование режимов электрических сетей выполнялось в Matlab Simulink. Результаты. Разработан алгоритм реконфигурации электрической сети для повышения ее пропускной способности на основе решения задач оптимизации нормальных режимов (статическая реконфигурация) и минимизации потребления электроэнергии без расчета установившихся режимов в темпе процессов изменения спроса на электроэнергию (динамическая реконфигурация). Для обеспечения допустимости режимов распределительных электрических сетей предложены подходы к управлению предложением активных (на базе возобновляемых источников) и реактивных мощностей и спросом активных потребителей. Представлены результаты реализации динамической реконфигурации для тестовой электрической схемы без учета управления предложением мощности и спросом активных потребителей, свидетельствующие об обоснованности предлагаемых подходов к повышению пропускной способности электрической сети.

Reconfiguration of intelligent electrical distribution networks of railways

The Digitalization of the power supply system and the introduction of sources of distributed generation based on renewable energy create new conditions for improving the efficiency of transport and distribution of electric energy. In normal operation, the 35/10 (6) kV distribution electric networks of railways have an open-ended structure and are partitioned in such a way as to be able to connect a group of substations to another power source in emergency or repair modes. Existing technologies for managing modes in these electrical networks do not imply the possibility of changing their topology to ensure the tasks of reducing overload and electricity losses in the pace of processes of change in demand for electricity in normal modes. As a rule, at present, the task of reconfiguring the electrical network arises when normal conditions are restored after accidents, when lines are overloaded, and if necessary, electrical equipment needs to be repaired according to the n-1 criterion, while optimizing the modes. The most important task of increasing the transmission capacity of distribution grids can be solved by reconfiguring them at the pace of changing the demand for electricity in normal conditions, without resorting to expensive reconstruction and increasing the installed capacity of electrical installations and lines. An algorithm for reconfiguring the electrical network has been developed to increase its capacity based on solving problems of optimizing normal modes (static reconfiguration) and minimizing power consumption without calculating steady-state modes in the pace of electricity demand changes (dynamic reconfiguration).To ensure the admissibility of the modes of distribution electric networks, approaches to managing the supply of active (based on renewable sources) and reactive capacities and the demand of active consumers have been proposed. There are the results of the implementation of dynamic reconfiguration for the test circuitry without taking into account the power supply and demand management of active consumers, indicating the validity of the proposed approaches to improving the capacity of the electrical network

An integrated approach to the creation of decentralized power supply systems based on gas turbine plants in the regions of the Far North

This article considers power supply of consumers in the Far North. It is proposed to use systems which include units operating on liquefied natural gas and hydrogen. Such units have a number of advantages over the currently used diesel power plants. The main advantage is a significant reduction of emissions to air and environmental pollution. The use of gas turbine units, comprising a turbine and a highspeed generator, also allows one to reduce the weight and dimensions of the power plant. The issues of choosing the structure of the power supply system for the given operating conditions are considered: the basic requirements are formulated and a list of quality indicators of the system functioning is determined.

Исследование наведенного напряжения в линии продольного электроснабжения

The processes arising during interaction between an AC contact system and two-wire-rail (TWR) lines are considered. The use of TWR lines in the longitudinal power supply system is stemming from two factors: the need to provide power supply for both railway and non-railway consumers situated along the railway or at a short distance from it, and achieving the maximum saving of financial resources for equipment and maintenance of the lines. The operation of a transformer connected to a TWR line is considered in detail. The losses in the transformer magnetic system and the transient occurring after the transformer magnetic core becomes saturated are studied. The theoretical curves of instantaneous voltage values on the elements of the considered electric circuits calculated from the formulas coincide with the obtained oscillograms of the same parameters recorded on a real transformer having the same electric circuit.

Инновационные принципы электроснабжения нетяговых потребителей железнодорожного транспорта

The issues of fundamental changes of electric power-supply of non-traction devices, such as, line-section devices and systems of railway transport are addressed in the article. It is clearly shown that the possibility of electric power-supply of such consumers without using the common high-voltage line-section power-supply lines of alternative voltage of 6 or 10 kV and respective power-supply substations can be implemented in practice. The essence of the proposed is that the electric power-supply source is not a high-voltage power-supply line, but a device which converts potential mechanical energy of a train, moving along a line section between signal points of railway automatic block system, into electrical one. Putting the described power-supply devices into operation provides technical as well as economic advantages over currently and widely used power-supply systems. The conversion of energy is carried out by changing magnetic resistance of a magnetic circuit, which includes railway car wheel-set in motion and direct neodymium magnet. Change in magnetic resistance due to the law of electromagnetic induction results in alternate voltage in the inductance coil, which is used as the electric power-supply source for non-traction line-section power consumers, including but not limited to, signal point of railway automatic block system. In case there is no wheel-set on the converter, electric power-supply for the power consumer is delivered by the electric energy accumulated in an ionistor (supercapacitor).

Development of an Adaptive Module for Control of Energy Supply of the Consumer in the Distributive Electrical Network 0,4 kV for Elimination of the Phase Load Unsymmetry

The paper considers the possibility of modeling the process of controlling the power supply of the consumer in the lower levels of network organizations to improve the quality indicators of electrical energy in the distribution electrical networks of 0.4 kV. The analysis of the process of control of indicators of the quality of electricity in the supply of energy to consumers. The block diagram of the adaptive power supply control module of the consumer and the algorithm of the control process are presented. A consumer power supply control module in 0.4 kV distribution networks is proposed.

Вдосконалення способів виконання захистів ліній зв’язку з підстанціями розосереджених джерел генерації

The article deals with the problems of using relay protection of power lines. Attention is paid to the peculiarities of the operation of protection under different modes of operation of these lines, namely: normal, post-accident and scheduled repair. The protection of two-sided power lines that connect individual local power plants to powerful electrical systems, including dispersed generation sources, local systems, and dispersed generation sources, must meet the general requirements of providing the required sensitivity, selectivity for various types of damage. Difficulties in providing the required sensitivity when using maximum current protections on such lines are associated with low levels of short-circuit currents from dispersed generation sources and local electrical systems. The features of the relay protection performance in redundant power supply of consumers using dispersed generation sources are given. The maximum operating current of the line consumed from the electrical system is 2 - 3 times the rated current, which is determined by the power of the generators of the dispersed sources of generation. In this case, the short-circuit currents from the low-power generators of the dispersed sources of generation are proportional to the maximum operating currents of the line. On double-sided power lines that connect local systems and dispersed power sources to a high-power electrical system, maximum current directional protection provides selectivity and are the main types of protection for such lines. Key words: power supply, relay protection, reclosers, sectionalizers, distributed sources of generation, short circuit, sectioning, selectivity

PROBLEMS OF COMMUNICATION LINES AND ELECTRIC TRANSMISSION LINES ON GENERAL SUPPORT IN CITY CONDITIONS

In the development of the energy industry in Russia, there has been a steady growth in the demand for electrical energy. Moreover, a significant increase in electricity consumption accounts for large cities. In rural areas, electricity consumption is mainly decreasing, which can be explained by the tendency of the outflow of the working-age population from the village and villages to the cities due to the lack of permanent work. However, when investing in the agro-industrial complex, with the development of farms, the demand for electricity also increases in villages. In addition, it is necessary to note the large-scale introduction of digital television and modern means of communication in holiday villages and villages. Thus, in the last decade, the demand for electricity throughout the country has increased significantly, which has led to an increase in communications and communications services, as well as consumers of these services. Since the easiest and most cost-effective way to provide consumer services and power supply is to lay down overhead lines and overhead power lines, it often happens that new customers are connected to already existing old (sometimes heavily worn out) lines. In addition to possible overloads of lines, a “tangle” of wires is formed at the intersections of overhead communication lines (VLS) and overhead transmission lines (VLE), which makes it difficult to carry out subsequent installation and repair work. The appearance of such a "tangle" creates an additional risk of injury to the worker when working at height. In order to reduce the complexity of maintenance and increase safety during operation, installation and maintenance of communication lines and power lines, a constructive solution has been proposed in junction intersections in the form of a traverse, which allows, firstly, to provide a greater number of attachment points and, secondly, to separate communication lines and power lines on different planes.

Compact household wind generator

Nowadays, there is a problem of further development of alternative energy for power supply of residential consumers. One of the areas of alternative energy is wind power. Wind generators offered to the public do not fully meet the requirements for household wind turbines. They are characterized by high cost; large weight and dimensions; installation complexity; impossibility of installation in cramped conditions; high noise and vibration. The article presents a physical model of a household wind generator with a wind guide device. Mass, dimension and energy characteristics of this de-vice are estimated. The presented construction of a household compact wind turbine can be used for power supply of residential consumers, small businesses, in the field of housing and communal services and in agricultural sector.

Effective electrical equipment operation process management based on automated information decision making support

The article studies the issues of ensuring electrical equipment operability during operation process, as an indicator of reliable and efficient power supply of heterogeneous consumers. The problem of electrical equipment operation process managing is considered from the point of view of many technical and economic factors that affecting decision making and the priority of taking measures to emergency prevention. The concept of information decision-making support, aimed at controlling the electrical equipment actual condition and planning work to ensure its operability in the short and long term, was proposed. An example of the information decision-making support implementation when choosing objects with the maximum risk of operability loss was given.

Study of the transients with the loss of field of the synchronous generator in the industrial electric power station

One of the main trends of industrial power engineering today is the need to improve the reliability of power supply of responsible consumers along with the increase of competitiveness of products by reducing cost. These requirements are ensured by the widespread introduction of distributed generation sources. These include mini combined heat and power unit, gas turbine, gas engine and combined-cycle gas turbine power plants. At the same time, such changes significantly complicate both the power supply system and possible modes of operation. One of the possible emergency modes in such networks is the loss of field of the synchronous generator. The admissibility of such a regime is specified by regulatory documents. In such a case this generator goes into asynchronous mode and consumes reactive power from the network. The aim of this work is to study the operation of a synchronous generator for a certain time in the asynchronous mode as a result of a loss of field and to develop measures to ensure the admissibility of such a mode in a complex looped network. An algorithm has been developed for calculating the electromechanical transients of a synchronous generator, taking into account the loss of machine field. Studies are carried out for various operational modes of an industrial power plant, taking into account the initial load of the generator using the KATRAN software package. The calculation results allow determining the generator load with active power, at which the synchronous generator can operate in the asynchronous mode without excitation.

Energy and Environment Assessment of Agricultural Application of Power Generating Sources

Introduction. Recently the issue of decentralised (autonomous) power supply of certain rural consumers has been increasingly considered. Various small power generators using local and renewable energy sources can be applied for this purpose. So a consumer must choose the best-suited energy-generating source. Materials and Methods.The findings of energy audits, which were conducted by the Institute from 2003 to the present day, were used to evaluate energy consumers and determine operation modes of equipment and load schedules. Complex index of the negative impact of heat and electricity generation on the environment was determined using the Spesivtsev ‒ Drozdov method of logical-linguistic modelling based on expert assessments. Results. Energy sources can be divided into traditional (diesel generators and gas generator plants) or renewable ones (wind turbines, solar collectors, mini hydro systems). Energy source is chosen either with the help of the economic criterion, being the cost of one k·Wh of energy or the criterion of environmental compatibility, or total specific emission of pollutants from energy generation at local generating sources (g/k·Wh). Here, not only the quantity of emissions, but also the harmful effect on the environment is considered. Discussion and Conclusion. For the choice of energy supply sources, the coefficient of energy-ecological compatibility is proposed, being the product of the cost of one k·Wh of energy generated and specific emission of pollutants. The optimal value of this factor is the smallest, which accounts for both economic and environmental feasibility of energy generating sources.

Research on Facilities of Power Supply of Small Power Capability Consumers of Bukhara Region by using Wind and Solar Energy

This article analyzes the climatic features of the Bukhara region – the southern-eastern part of Uzbekistan. The wind and solar potential of the region and the prospects of its utilization were evaluated. In recent years, wind and solar energy has been analyzed worldwide. The potential for the use of solar radiation in the region was analyzed. Accordingly, when the solar photovoltaic batteries in the region are used (coefficient of efficiency-18%), the technical potential of the region is 41 TWh/year. Wind speeds and wind energy potential data were collected over eight years (2011-2018) and were calculated using the monthly wind speed data measured every 30 minutes at a height of 10m. During the estimation of wind energy potential we were used two parameters Weibull and Rayleigh distribution functions. The density power and energy values of the wind flow at various heights were evaluated using the extrapolation method. In accordance with that, on height of 10m it makes 41.19 W/m2 and 361.48 kWh/m2, on height of 50m 117.23 W/m2 1026.96 kWh/m2, and on height of 100m 192.76 W/m2, 1688.59 kWh/m2. The wind energy gross, technical and economic potential of the region has been evaluated. In addition, the potential and prospects of using hybrid (wind and solar) power stations for the supply of uninterrupted and reliable power supply to consumers in the region were analyzed

(Invited) RKP Vanadium Flow Battery and its Application

Vanadium flow battery(VFB) is deemed to be one of the most promising technologies for large-scale industrial energy storage, due to its attractive features like flexible capacity, active thermal management, long cycle life and high safety. Dalian Rongke Power Co., Ltd. (RKP) has been devoted to the fundmental study and advanced research of Vanadium flow battery applications. It has become one of the world-leading enterprises in VFB development, manufacturing and delivery industry. The products have evolved from earlier indoor structure to the latest containerized system designs. More than a dozen VRFB systems have been deployed and end products have been launched into operations across the world over the past decades. The 500kW/2MWh VFB product was developed for the large scale energy application, which is consisted of 16 cell stacks. The high integration level, low shunt current loss, low auxiliary power supply consumption and high reliability were achieved. The novel cell stack is designed by optimizing the key materials and cell stack structure, which can achieve a better performance and higher reliability at a relatively low cost. The energy efficiency(EE) could reach 80% at the rated power of 33kW, and the current density could be improved to 140~150 mA/cm2.The cycle life test indicated that no obvious performance decay was found even after 10000 cycles. The advanced two-stage power conversion system (PCS) was selected in order to realiaze the independent control of each sub-systems, which would improve the overall reliability ultimately. The AC/AC energy efficiency could reach 70% at the rated power of 500kW. The 500kW/2MWh VFB product has been installed in power plants for wind and solar energy storage and has obtained better application effect. The world largest battery system, a 200MW/800MWh VFB peaking power plant conducted by RKP, is currently in progress in Dalian, China. The purpose is to improve the Northeast grid resiliency and facilitate smooth integration of renewables. A 500kW/2MWh VFB product is the minimum storage unit of the project. Each unit product could be controled independently. The foreseeable success of the project would exert great influence on the development of the flow battery in the future. In this presentation, new technolgy and product developments of vanadium flow battery at RKP will be introduced and further challenges will be addressed as well.

Boron-Doped Diamond for Hydroxyl Radical and Sulfate Radical Anion Electrogeneration, Transformation, and Voltage-Free Sustainable Oxidation.

Boron-doped diamond-based electrochemical advanced oxidation processes (BDD-EAOPs) have attracted much attention. However, few systematic studies concerning the radical mechanism in BDD-EAOPs have been published. In situ electron paramagnetic resonance spectrometry is used to confirm that SO4•- is directly electrogenerated from SO42- . Then, excess SO4•- dimerizes to form S2 O82- and accumulates in the BDD-EAOP system. But no S2 O82- accumulates at pH = 10 owing to the rapid transformation of SO4•- and S2 O82- . Above the overpotential of water oxidation, • OH is electrogenerated and cooperated with SO4•- . In the power-off phase, the accumulated S2 O82- can be reactivated to SO4•- via specific degradation intermediates to achieve sustainable degradation. Di-n-butyl phthalate (DnBP), a typical endocrine disruptor, is selected as a model contaminant. Surprisingly, 99.8% of DnBP (initial concentration of 1 mg L-1 ) is removed, using an intermittent power supply strategy with a periodic 10 min power-on phase at a duty ratio of 1:2, reducing the electrical energy consumption (1.8 kWh m-3 ) by more than 30% compared with continuous power supply consumption. These radical electrogeneration transformation mechanisms reveal an important new strategy for sustainable oxidation, especially for in situ water restoration, and are expected to provide a theoretical basis for BDD applications.

IMPROVING THE QUALITY OF ELECTRIC POWER IN LOW VOLTAGE NETWORKS

This article is devoted to development of actions for improvement of quality of the electric power in low voltage networks, by installation of booster transformers (BT), and to calculation of economic effect in comparison with alternative versions of the solution of tasks of ensuring reliable, high-quality and available power supply of consumers.