Dispersed Power Sources Research Articles

Smart transportation systems using learning method for urban mobility and management in modern cities

The pressing demand for an escalation in renewable energy production arises from the surge in power consumption, escalating environmental concerns, and the exhaustion of fossil fuels. Microgrids, featuring dispersed power sources, exhibit superior resilience, efficiency, and stability in contrast to conventional power grids. Noteworthy investments in eco-friendly initiatives have been made by various major corporations, particularly in institutional structures. The current research advocates for the integration of photovoltaics, energy storage, and electric vehicles (EVs) as pivotal elements in a smart grid. This study introduces an optimal energy management system (EMS) designed to efficiently allocate power from existing sources. To address the challenges within an uncertain and reliable environment, a stochastic framework leveraging the whale optimization algorithm and unscented transform has been formulated. All simulations have been executed using the digital twin of the smart grid components. Results suggest that the proposed EMS ensures uninterrupted power supply, contributing to a substantial 45% reduction in energy costs. Furthermore, the potential of EVs as storage devices is explored. When employed as energy sources, EVs led to a noteworthy 45.58% reduction in power prices, while their use as loads still yielded a significant 19.33% decrease. The study also delves into the analysis of outage effects on the continuous power supply cost.

An overview of AC and DC microgrid energy management systems

<abstract> <p>In 2022, the global electricity consumption was 4,027 billion kWh, steadily increasing over the previous fifty years. Microgrids are required to integrate distributed energy sources (DES) into the utility power grid. They support renewable and nonrenewable distributed generation technologies and provide alternating current (AC) and direct current (DC) power through separate power connections. This paper presents a unified energy management system (EMS) paradigm with protection and control mechanisms, reactive power compensation, and frequency regulation for AC/DC microgrids. Microgrids link local loads to geographically dispersed power sources, allowing them to operate with or without the utility grid. Between 2021 and 2028, the expansion of the world's leading manufacturers will be driven by their commitment to technological advancements, infrastructure improvements, and a stable and secure global power supply. This article discusses iterative, linear, mixed integer linear, stochastic, and predictive microgrid EMS programming techniques. Iterative algorithms minimize the footprints of standalone systems, whereas linear programming optimizes energy management in freestanding hybrid systems with photovoltaic (PV). Mixed-integers linear programming (MILP) is useful for energy management modeling. Management of microgrid energy employs stochastic and robust optimization. Control and predictive modeling (MPC) generates energy management plans for microgrids. Future microgrids may use several AC/DC voltage standards to reduce power conversion stages and improve efficiency. Research into EMS interaction may be intriguing.</p> </abstract>

220 ㎚ 대역의 아크광 검출을 위한 교정시스템 구현

The demand for renewable energy equipment and power equipment for use in electric railways has been increasing owing to the expansion of dispersed power sources and urban railroads. Arc flashes occur because of insulation breakdown, leakage, and contact loss, and it may cause electric fires in DC power equipment. Arc flashes are detected by temperature, pressure, acoustic, light, and electrical methods. The photosensor detection is a noncontact method but has the disadvantage of high external noise owing to sunlight depending on the wavelength band from among these. An arc detector in the 220-nm ultraviolet (UV) light is developed to reduce noise and is not affected by sunlight. However, there is no prior research on the deterioration of electrical equipment when using arc discharge. Therefore, correcting errors, such as light density, generation time, and distance, through arc flash replay is necessary to determine the deterioration of DC power equipment. In this paper, we propose a calibration system for reproducing an arc flash in the 220-nm UV light. The calibration system comprises a 150-W light source and a xenon-series chopper disc, and the result of the photosensor response to 220-nm UV light is noted.

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

IMPROVING THE DYNAMICS OF AN INVERTER-BASED PV GENERATOR DURING LOAD DUMPS

In distribution power grids supplied by dispersed power sources, for example RES (Renewable Energy Sources), in the event of a load dump, unexpected transient states may appear. These states involve a dangerous increase in voltage or current. This situation may lead to the disconnection of these sources. To prevent this phenomenon, a non-linear anti-windup regulator with a conditional integrator has been proposed. This solution allows a significant improvement of the generator’s dynamic properties both at load dump and on return to full load.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011. In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities and recent trends on SOFC, including a program “Technology development for promoting SOFC commercialization” , will be overviewed.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting development and demonstrative research projects relating to the solid oxide fuel cell (SOFC), as it is one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of NEDO’s achievements was the world’s first commercialization of an SOFC-based combined heat and power (CHP) system called ENE-FARM type S in 2011. In June 2014, Japan’s Ministry of Economy, Trade and Industry (METI) formulated its Strategic Road Map for Hydrogen and Fuel Cells. In accordance with the road map, it was planned to release fuel cells for commercial and industrial use onto the market in 2017 as one of the processes for expanding the use of fuel cell technology. NEDO’s activities, including its Technology Development for Promotion of Practical Applications of Solid Oxide Fuel Cells project, and recent trends in the SOFC field, are overviewed here.

A Next‐Generation Distribution Automation System Using IEC 61850 GOOSE and Section Switches with Sensors

SUMMARYMore and more dispersed power sources will be introduced to achieve a low‐carbon society. However, many problems may occur as a result of excessive introduction in the current power system. For example, delays or failures of fault detection may occur due to a decline in protective relay sensitivity. This paper proposes a new system of protective relays for distribution lines using section switches with sensors to solve the problem. In addition, experimental results on the proposed system composed of Intelligent Electronic Devices based on IEC 61850 are presented.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011. In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities on SOFC, including a program “Technology development for promoting SOFC commercialization” , will be overviewed.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011. In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities on Solid Oxide Fuel Cell (SOFC), including a program “Technology development for promoting SOFC commercialization”, will be overviewed.

Engineering the Early Demise of Fossil Fuels

Climate change is now scientific fact, and it is equally firmly established that it is of anthropogenic origins, mainly attributed to the burning of fossil fuels. If future generations are to inherit a living, and livable planet, which is self-evidently their right, the current inhabitants have no alternative but to dispense with fossil fuels as a source of power. It is demonstrated here that technically this can clearly be secured before 2050 by transitioning to renewable sources of energy, backed up by ‘clean’ nuclear power. However, effective deployment of these geographically widely dispersed power sources will require power sharing among groups of nations and grid interconnections on a continent spanning basis. It is suggested that effective progress towards the realization of such distributed systems is unlikely to be achieved without cooperative planning and implementation across many nations. An example of this is beginning to emerge in Europe.

Decision trees aided scheduling for firm power capacity provision by virtual power plants

The incorporation of Distributed Generation (DG) under the Virtual Power Plant (VPP) concept allows the market integration of several and largely dispersed electric power sources. One matter of concern for the VPP owner and operator is to follow the hourly schedule regardless of the stochastic nature of some of its sources or any unpredicted generation outages. This study presents a Decision Tree (DT) based methodology that prepares for the dispatching of power equivalent to the possible loss of the highest injection of one of the sources of the VPP (according to day-ahead hourly schedule) to the rest of its sources, on an hour-ahead horizon. This allows VPP operators to provide firm capacity and participate effectively in the energy market.

A Surge Analysis in a System Connected with Dispersed Power Sources

A Surge Analysis in a System Connected with Dispersed Power Sources

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research projects on SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of the achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) residential system in 2011. Cost reduction and durability improvements of SOFCs, however, still remain critical issues for their further widespread commercialization. In this paper, two NEDO projects relating to SOFCs, “Development of System and Elemental Technologies on SOFC” (FY 2008-2012) and “Technology Development for promoting SOFC commercialization” (FY 2013- 2017) will be introduced.

Regulation of Parallel Converters with Respect to Stored Energy and Passivity Characteristics

A regulation of converters connected in parallel is discussed considering their stored energy and passivity characteristics. From the viewpoint of stored energy, a new regulation method to conserve and share the stored energy can be found. The energy stored in inductors and capacitors is transferred to loads so that the load keeps the energy dissipation constant. Though numerical simulation, the method is validated for a parallel converter system.

Multi-Deployment of Dispersed Power Sources Using RBF Neural Network

Multi-deployment of dispersed power sources became an important need with the rapid increase of the Distributed generation (DG) technology and smart grid applications. This paper proposes a computational tool to assess the optimal DG size and deployment for more than one unit, taking the minimum losses and voltage profile as objective functions. A technique called radial basis function (RBF) neural network has been utilized for such target. The method is only depending on the training process; so it is simple in terms of algorithm and structure and it has fast computational speed and high accuracy; therefore it is flexible and reliable to be tested in different target scenarios. The proposed method is designed to find the best solution of multi- DG sizing and deployment in 33-bus IEEE distribution system and create the suitable topology of the system in the presence of DG. Some important results for DG deployment and discussion are involved to show the effectiveness of our proposed method.

Reduction of power fluctuation by distributed generation in micro grid

AbstractRenewable forms of energy such as wind power or photovoltaic energy are environmentally focused, but the fluctuation of the output power of such renewable forms of energy may cause excessive variation of the voltage or frequency of the grid. Increasing the amount of renewable energy would degrade the quality of the grid. Micro grids, in which dispersed power sources compensate variations in the generation of renewable energy, can expand the limits of installation of renewable forms of energy by maintaining the quality of the interconnected grid. This paper discusses the use of gas turbines to absorb power variations from wind generation and the loads. In order to control the output power, gas turbines must run under partial load, which results in lower efficiency. An evaluation of the micro grids is made with consideration of their efficiency, the installed capacity of wind power generation systems, and frequency stability for islanded operation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 22–29, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20462

Multi-Agent Based Operation and Control of Isolated Power System with Dispersed Power Sources Including New Energy Storage Device

This paper presents a multi-agent based operation and control of isolated power systems with dispersed power sources such as photo-voltaic units, wind generation units, diesel generation units, and new energy storage devices such as the Energy Capacitor System (ECS). An advanced automatic generation control (AGC) scheme has been proposed through the coordination between the diesel unit and the ECS with small capacity. All the required information for the proposed multi- agent based AGC is distributed among intelligent agents through the computer network. All the AGC function is achieved by using the proposed multi-agent based control system. To demonstrate the efficiency of the proposed multi- agent based scheme, analog simulator tests have been performed. Simulations results indicate that the AGC performance has been highly improved by the proposed multi- agent based AGC scheme even in the existence of the communication delay time through computer networks.

1118. クリーン開発メカニズムを活用した中国への原子力導入方策の検討

This paper examines an introduction scenario for nuclear power in China using the Clean Development Mechanism as a financial support for construction, based on quantitative evaluation of energy demand forecasts and the nuclear fuel cycle through 2100. The results of the case study concluded that in the short to mid term, large-scale light water reactors will primarily be sited in coastal areas where infrastructure development is advanced. In the future, as dispersed power sources in inland areas, small scale-metallic fuel FBRs will be preferred due to their promising safety, large breeding capacity, operation and maintenance characteristics, ease of transportation of plant equipment and plant construction and the possibility of on-site nuclear fuel cycle.

Studies on steady-state stability of looped power systems and stabilization by SMES

With the increasing number of dispersed power sources interconnected to the power supply system, power systems can take a form similar to that of a longitudinal system. Also, they can become looped, with both ends of the longitudinal system connected to each other. In the present paper, the steady-state stability of longitudinal power systems and looped power systems is analyzed by means of the mode analysis method via eigenvalue and eigenvector calculation, and power system stabilization by SMES (Superconducting Magnetic Energy Storage) for looped systems is examined relative to that for longitudinal systems. © 2000 Scripta Technica, Electr Eng Jpn, 133(3): 48–54, 2000