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Sample records for certs microgrid laboratory

  1. CERTS Microgrid Laboratory Test Bed - PIER Final Project Report

    Eto, Joseph H.; Eto, Joseph H.; Lasseter, Robert; Schenkman, Ben; Klapp, Dave; Linton, Ed; Hurtado, Hector; Roy, Jean; Lewis, Nancy Jo; Stevens, John; Volkommer, Harry

    2008-07-25

    The objective of the CERTS Microgrid Laboratory Test Bed project was to enhance the ease of integrating small energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of small generating sources. The techniques comprising the CERTS Microgrid concept are: 1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation; 2) an approach to electrical protection within the microgrid that does not depend on high fault currents; and 3) a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications. The techniques were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers 1547 and power quality requirements. The electrical protections system was able to distinguish between normal and faulted operation. The controls were found to be robust and under all conditions, including difficult motor starts. The results from these test are expected to lead to additional testing of enhancements to the basic techniques at the test bed to improve the business case for microgrid technologies, as well to field demonstrations involving microgrids that involve one or mroe of the CERTS Microgrid concepts.

  2. Value and Technology Assessment to Enhance the Business Case for the CERTS Microgrid

    Lasseter, Robert; Eto, Joe

    2010-05-15

    The CERTS Microgrid concept is an advanced approach for enabling integration of, in principle, an unlimited quantity of distributed energy resources into the electricity grid. A key feature of a microgrid, is its ability, during a utility grid disturbance, to separate and isolate itself from the utility seamlessly with no disruption to the loads within the microgrid (including no reduction in power quality). Then, when the utility grid returns to normal, the microgrid automatically resynchronizes and reconnects itself to the grid, in an equally seamless fashion. What is unique about the CERTS Microgrid is that it can provide this technically challenging functionality without extensive (i.e., expensive) custom engineering. In addition, the design of the CERTS Microgrid also provides high system reliability and great flexibility in the placement of distributed generation within the microgrid. The CERTS Microgrid offers these functionalities at much lower costs than traditional approaches by incorporating peer-to-peer and plug-and-play concepts for each component within the Microgrid. The predecessor to the current project involved the construction of and completion of initial testing using the world's first, full-scale, inverter-based, distributed generation test bed. The project demonstrated three advanced techniques, collectively referred to as the CERTS Microgrid concept, which collectively significantly reduce the level of custom field engineering needed to operate microgrids consisting of small generating sources. The techniques are: (1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation; (2) an approach to electrical protection within the microgrid that does not depend on high fault currents; and (3) a method for microgrid control that achieves voltage and frequency stability under both grid and islanded conditions without requiring high-speed communications. The work conducted in this phase of

  3. A virtual laboratory for micro-grid information and communication infrastructures

    Weimer, James; Xu, Yuzhe; Fischione, Carlo; Johansson, Karl Henrik; Ljungberg, Per; Donovan, Craig; Sutor, Ariane; Fahlén, Lennart E.

    2012-01-01

    Testing smart grid information and communication (ICT) infrastructures is imperative to ensure that they meet industry requirements and standards and do not compromise the grid reliability. Within the micro-grid, this requires identifying and testing ICT infrastructures for communication between distributed energy resources, building, substations, etc. To evaluate various ICT infrastructures for micro-grid deployment, this work introduces the Virtual Micro-Grid Laboratory (VMGL) and provides ...

  4. Flexible System Integration and Advanced Hierarchical Control Architectures in the Microgrid Research Laboratory of Aalborg University

    Meng, Lexuan; Hernández, Adriana Carolina Luna; Diaz, Enrique Rodriguez

    2016-01-01

    This paper presents the system integration and hierarchical control implementation in an inverter-based microgrid research laboratory (MGRL) in Aalborg University, Denmark. MGRL aims to provide a flexible experimental platform for comprehensive studies of microgrids. The structure of the laborato...

  5. Microgrids

    Soshinskaya, Mariya; Graus, Wina; Guerrero, Josep M.

    2014-01-01

    Although microgrids have been researched for over a decade and recognized for their multitude of benefits to improve power reliability, security, sustainability, and decrease power costs for the consumer, they have still not reached rapid commercial growth. The main aim of this research is to ide......Although microgrids have been researched for over a decade and recognized for their multitude of benefits to improve power reliability, security, sustainability, and decrease power costs for the consumer, they have still not reached rapid commercial growth. The main aim of this research...... barriers were identified and grouped into four categories: technical, regulatory, financial, and stakeholder, based on the literature and overlying patterns recognized amongst the thirteen case studies. The most common technical barriers include problems with technology components, dual-mode switching from...... costs of the microgrid. This can be resolved with proper market support in the short term and might naturally resolve itself through learning over the long run. Lastly, stakeholder barriers include issues with conflicting self-interest and trust, and having the expertise to manage operations...

  6. Intelligent DC Microgrid Living Laboratories - A Chinese-Danish Cooperation Project

    Diaz, Enrique Rodriguez; Su, Xiaoling; Savaghebi, Mehdi

    2015-01-01

    This paper presents a research project focus on the development of future intelligent direct-current (DC) microgrids which is being deployed for highly efficient integration of distributed generation and modern electronic loads. The project is based on the collaboration between research institutes...... in China and Denmark, aiming to explore the different aspects of DC microgrids: design, modelling, control, coordination, communications and management. In addition, a future Living Laboratory will also be integrated into the Intelligent DC Microgrids Laboratory, which will serve as demonstration facility...... for low voltage direct-current (LVDC) distribution systems. Research is carried out in both Intelligent DC Microgrid Laboratories, focused on industry in China and residential applications in Denmark....

  7. CERT in the organisation

    Tolido, R.; Borsoi, P.; Bronk, H.; Elsinga, B.; Greuter, R.; Hafkamp, W.H.M.; Jochem, A.; van der Heide, M.; Rorive, K.; Schiltmans, T.; Schuurman, J.; Reijers, R.

    This Expert Letter deals with the increasingly important phenomenon of in-house Computer Emergency Response Teams (CERTs). The number of internal CERTs in larger, commercial organisations has increased rapidly in the past few years. This is mainly in response to the painful security incidents that

  8. CERTS customer adoption model

    Rubio, F. Javier; Siddiqui, Afzal S.; Marnay, Chris; Hamachi,Kristina S.

    2000-03-01

    This effort represents a contribution to the wider distributed energy resources (DER) research of the Consortium for Electric Reliability Technology Solutions (CERTS, http://certs.lbl.gov) that is intended to attack and, hopefully, resolve the technical barriers to DER adoption, particularly those that are unlikely to be of high priority to individual equipment vendors. The longer term goal of the Berkeley Lab effort is to guide the wider technical research towards the key technical problems by forecasting some likely patterns of DER adoption. In sharp contrast to traditional electricity utility planning, this work takes a customer-centric approach and focuses on DER adoption decision making at, what we currently think of as, the customer level. This study reports on Berkeley Lab's second year effort (completed in Federal fiscal year 2000, FY00) of a project aimed to anticipate patterns of customer adoption of distributed energy resources (DER). Marnay, et al., 2000 describes the earlier FY99 Berkeley Lab work. The results presented herein are not intended to represent definitive economic analyses of possible DER projects by any means. The paucity of data available and the importance of excluded factors, such as environmental implications, are simply too important to make such an analysis possible at this time. Rather, the work presented represents a demonstration of the current model and an indicator of the potential to conduct more relevant studies in the future.

  9. Comprehensive Error Rate Testing (CERT)

    U.S. Department of Health & Human Services — The Centers for Medicare and Medicaid Services (CMS) implemented the Comprehensive Error Rate Testing (CERT) program to measure improper payments in the Medicare...

  10. Advancing Microgrid Research at NREL

    2018-04-25

    NREL expanded its microgrid research capabilities at the Energy System Integration Facility (ESIF) with the purchase of a Schweitzer Engineering Laboratories (SEL) microgrid controller, resulting in a more comprehensive microgrid research platform. NREL's microgrid research platform allows manufacturers, utilities, and integrators to develop and evaluate their technology or configuration at full power before implementation - something only possible at a handful of facilities in the world.

  11. Boston Community Energy Study - Zonal Analysis for Urban Microgrids

    2016-04-05

    Lincoln Laboratory. Figure 1 elucidates how Boston’s parcels are dominated by residential archetypes , which are depicted in red on the map. Figure 3...microgrid zones were divided into three separate archetypes : multiuser microgrids, energy justice microgrids, and emergency microgrids, as discussed

  12. Scoping Study: Networked Microgrids.

    Trinklei, Eddy; Parker, Gordon; Weaver, Wayne; Robinett, Rush; Babe Gauchia, Lucia; Ten, Chee-Wooi; Bower, Ward; Glover, Steven F.; Bukowski, Steve

    2014-10-01

    This report presents a scoping study for networked microgrids which are defined as "Interoperable groups of multiple Advanced Microgrids that become an integral part of the electricity grid while providing enhanced resiliency through self-healing, aggregated ancillary services, and real-time communication." They result in optimal electrical system configurations and controls whether grid-connected or in islanded modes and enable high penetrations of distributed and renewable energy resources. The vision for the purpose of this document is: "Networked microgrids seamlessly integrate with the electricity grid or other Electric Power Sources (EPS) providing cost effective, high quality, reliable, resilient, self-healing power delivery systems." Scoping Study: Networked Microgrids September 4, 2014 Eddy Trinklein, Michigan Technological University Gordon Parker, Michigan Technological University Wayne Weaver, Michigan Technological University Rush Robinett, Michigan Technological University Lucia Gauchia Babe, Michigan Technological University Chee-Wooi Ten, Michigan Technological University Ward Bower, Ward Bower Innovations LLC Steve Glover, Sandia National Laboratories Steve Bukowski, Sandia National Laboratories Prepared by Michigan Technological University Houghton, Michigan 49931 Michigan Technological University

  13. Resilient Renewable Energy Microgrids

    Anderson, Katherine H [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DiOrio, Nicholas A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Butt, Robert S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cutler, Dylan S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Richards, Allison [Unaffiliated

    2017-11-14

    This presentation for the Cable-Tec Expo 2017 offers information about how renewable microgrids can be used to increase resiliency. It includes information about why renewable energy battery diesel hybrids microgrids should be considered for backup power, how to estimate economic savings of microgrids, quantifying the resiliency gain of microgrids, and where renewable microgrids will be successful.

  14. CERT TST December 2015 Visit Summary

    Little, Robert Currier [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bailey, Teresa S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gamblin, G. Todd [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Olinger, Chad Tracy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pautz, Shawn D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Williams, Alan B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-25

    The annual PSAAP II TST visit to Texas A&M’s CERT Center was held on December 1-3, 2015. The agenda for the visit is attached. Non-TAMU attendees were: TST Members – Teresa Bailey (LLNL), Todd Gamblin (LLNL), Bob Little (LANL) – Chair, Chad Olinger (LANL), Shawn Pautz (SNL), Alan Williams (SNL);Other Lab staff – Skip Kahler (LANL), Ana Kupresanin (LLNL), and Rob Lowrie (LANL); AST Members – Nelson Hoffman (LANL) and Bob Voigt (Leidos) The TST wishes to express our appreciation to all involved with CERT for the high-quality posters and presentations and for the attention to logistics that enabled a successful visit. We have broken our comments into four sections: (1) Kudos, (2) Recommendations, (3) Feedback on Priorities for April Review, and (4) Follow-Up Activities with Labs.

  15. Consensus on Exercise Reporting Template (CERT)

    Slade, Susan C; Dionne, Clermont E; Underwood, Martin

    2016-01-01

    the reporting of exercise programs in all evaluative study designs and contains 7 categories: materials, provider, delivery, location, dosage, tailoring, and compliance. The CERT will encourage transparency, improve trial interpretation and replication, and facilitate implementation of effective exercise......BACKGROUND: Exercise interventions are often incompletely described in reports of clinical trials, hampering evaluation of results and replication and implementation into practice. OBJECTIVE: The aim of this study was to develop a standardized method for reporting exercise programs in clinical...... trials: the Consensus on Exercise Reporting Template (CERT). DESIGN AND METHODS: Using the EQUATOR Network's methodological framework, 137 exercise experts were invited to participate in a Delphi consensus study. A list of 41 items was identified from a meta-epidemiologic study of 73 systematic reviews...

  16. A Novel Control Strategy for Autonomous Operation of Isolated Microgrid with Prioritized Loads

    Kumar, R. Hari; Ushakumari, S.

    2018-05-01

    Maintenance of power balance between generation and demand is one of the most critical requirements for the stable operation of a power system network. To mitigate the power imbalance during the occurrence of any disturbance in the system, fast acting algorithms are inevitable. This paper proposes a novel algorithm for load shedding and network reconfiguration in an isolated microgrid with prioritized loads and multiple islands, which will help to quickly restore the system in the event of a fault. The performance of the proposed algorithm is enhanced using genetic algorithm and its effectiveness is illustrated with simulation results on modified Consortium for Electric Reliability Technology Solutions (CERTS) microgrid.

  17. Microgrids architectures and control

    Hatziargyriou, Nikos

    2014-01-01

    Microgrids are the most innovative area in the electric power industry today. Future microgrids could exist as energy-balanced cells within existing power distribution grids or stand-alone power networks within small communities. A definitive presentation on all aspects of microgrids, this text examines the operation of microgrids - their control concepts and advanced architectures including multi-microgrids. It takes a logical approach to overview the purpose and the technical aspects of microgrids, discussing the social, economic and environmental benefits to power system operation. The bo

  18. Autonomous Operation of Low Voltage Microgrids

    Irena Wasiak

    2014-12-01

    Full Text Available The article describes the possibilities of LV microgrids operation in the island mode. Control strategies of energy sources connected to the grid by means of invertors are discussed, either for a microgrid connected to the supplying network or during the island mode operation. The presented results of research were conducted at the Laboratory of Distributed Generation at Lodz University of Technology. The study was performed for two variants of reference voltage source: the battery storage and microturbine respectively.

  19. Microgrid Controller and Advanced Distribution Management System Survey Report

    Liu, Guodong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Starke, Michael R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Herron, Andrew N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-07-01

    A microgrid controller, which serves as the heart of a microgrid, is responsible for optimally managing the distributed energy resources, energy storage systems, and responsive demand and for ensuring the microgrid is being operated in an efficient, reliable, and resilient way. As the market for microgrids has blossomed in recently years, many vendors have released their own microgrid controllers to meet the various needs of different microgrid clients. However, due to the absence of a recognized standard for such controllers, vendor-supported microgrid controllers have a range of functionalities that are significantly different from each other in many respects. As a result the current state of the industry has been difficult to assess. To remedy this situation the authors conducted a survey of the functions of microgrid controllers developed by vendors and national laboratories. This report presents a clear indication of the state of the microgrid-controller industry based on analysis of the survey results. The results demonstrate that US Department of Energy funded research in microgrid controllers is unique and not competing with that of industry.

  20. Local hierarchical control for industrial microgrids with improved frequency regulation

    Rey, Juan M.; Vergara, Pedro P.; Castilla, Miguel

    2018-01-01

    Local control strategies that operate without relying on communication systems enhance flexibility and reliability of AC industrial microgrids. Based on a previous work in which a secondary switched control was proposed, this paper presents a complementary strategy to improve the frequency......-use of communications. Experimental results obtained on a laboratory microgrid are presented to validate the performance of the proposed complementary control strategy....

  1. Networked Microgrids Scoping Study

    Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dobriansky, Larisa [General MicroGrids, San Diego, CA (United States); Glover, Steve [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Liu, Chen-Ching [Washington State Univ., Pullman, WA (United States); Looney, Patrick [Brookhaven National Lab. (BNL), Upton, NY (United States); Mashayekh, Salman [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pratt, Annabelle [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schneider, Kevin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stadler, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Starke, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Yue, Meng [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-12-05

    Much like individual microgrids, the range of opportunities and potential architectures of networked microgrids is very diverse. The goals of this scoping study are to provide an early assessment of research and development needs by examining the benefits of, risks created by, and risks to networked microgrids. At this time there are very few, if any, examples of deployed microgrid networks. In addition, there are very few tools to simulate or otherwise analyze the behavior of networked microgrids. In this setting, it is very difficult to evaluate networked microgrids systematically or quantitatively. At this early stage, this study is relying on inputs, estimations, and literature reviews by subject matter experts who are engaged in individual microgrid research and development projects, i.e., the authors of this study The initial step of the study gathered input about the potential opportunities provided by networked microgrids from these subject matter experts. These opportunities were divided between the subject matter experts for further review. Part 2 of this study is comprised of these reviews. Part 1 of this study is a summary of the benefits and risks identified in the reviews in Part 2 and synthesis of the research needs required to enable networked microgrids.

  2. 75 FR 81632 - Australia Beef Imports Approved for the Electronic Certification System (eCERT)

    2010-12-28

    ... for the Electronic Certification System (eCERT) AGENCY: Customs and Border Protection, Department of... restraints will be accomplished through the Electronic Certification System (eCERT). Beginning on that date... Fisheries and with the approval of the United States Government. DATES: The use of the eCERT process for all...

  3. A Green Prison: The Santa Rita Jail Campus Microgrid

    Marnay, Chris; DeForest, Nicholas; Lai, Judy

    2012-01-22

    A large microgrid project is nearing completion at Alameda County’s twenty-two-year-old 45 ha 4,000-inmate Santa Rita Jail, about 70 km east of San Francisco. Often described as a green prison, it has a considerable installed base of distributed energy resources (DER) including an eight-year old 1.2 MW PV array, a five-year old 1 MW fuel cell with heat recovery, and considerable efficiency investments. A current US$14 M expansion adds a 2 MW-4 MWh Li-ion battery, a static disconnect switch, and various controls upgrades. During grid blackouts, or when conditions favor it, the Jail can now disconnect from the grid and operate as an island, using the on-site resources described together with its back-up diesel generators. In other words, the Santa Rita Jail is a true microgrid, or μgrid, because it fills both requirements, i.e. it is a locally controlled system, and it can operate both grid connected and islanded. The battery’s electronics includes Consortium for Electric Reliability Technology (CERTS) Microgrid technology. This enables the battery to maintain energy balance using droops without need for a fast control system.

  4. Microgrids | Grid Modernization | NREL

    microgrids enable local power generation assets-including traditional generators, renewables, and storage-to select electrical nodes on the microgrid Programmable DC power supplies to emulate photovoltaic (PV operation was validated in a power hardware-in-the-loop experiment using a programmable DC power supply to

  5. Clean energy microgrids

    Obara, Shin'ya

    2017-01-01

    This book describes the latest technology in microgrids and economic, environmental and policy aspects of their implementation, including microgrids for cold regions, and future trends. The aim of this work is to give this complete overview of the latest technology around the world, and the interrelation with clean energy systems.

  6. Technical solutions for low-voltage microgrid concept

    Laaksonen, H.

    2011-07-01

    Future electricity distribution networks with large amount of distributed energy resources will require creation of a totally new smart grid architecture. The micro grid concept is expected to play a major role in the new smart grid architecture. A special feature of microgrids is that during disturbances in the utility grid they can continue operation automatically in the island mode so that electricity supply to microgrid customers can be continued without any interruption. Thereby, the microgrid concept allows the reliability benefit of distributed energy resources to be realized while also fulfilling the future energy efficiency requirements. In this thesis a total technical concept for low-voltage microgrid which could be integrated into the future smart grids has been developed and specified. The key technical challenges of low-voltage microgrids are the transition to island operation, the power quality management and the microgrid protection especially during island operation. Essential part of the concept development involved the development of solutions and operation principles to these key technical challenges of low-voltage microgrids so that all these solutions would be compatible with each other. The role of one central energy storage unit and the location of it are very important in the developed concept from the low-voltage microgrid management and protection point of view. The development work with the related technical challenges was carried out in this thesis with PSCAD simulation software. PSCAD enabled the examination of a simultaneous interaction of different types of distributed energy resource units and loads both in the normal utility grid connected and in the island operation mode of the microgrid. This information from simulations with multiple component configurations was essential when the technical solutions were developed and these studies could not have been undertaken to this extent in a laboratory environment without major

  7. Defining a Progress Metric for CERT RMM Improvement

    2017-09-14

    REV-03.18.2016.0 Defining a Progress Metric for CERT-RMM Improvement Gregory Crabb Nader Mehravari David Tobar September 2017 TECHNICAL ...fendable resource allocation decisions. Technical metrics measure aspects of controls implemented through technology (systems, soft- ware, hardware...implementation metric would be the percentage of users who have received anti-phishing training . • Effectiveness/efficiency metrics measure whether

  8. How Lafd Cert May Be Understood as a Smart Practice: How it is Pioneering a Transition to Whole Community Cert and How it Can Serve as the Template for Cert Programs Nationally

    2017-01-10

    United States as a framework for organizing citizens to be more prepared. Using an appreciative inquiry approach, this thesis investigated how LAFD...established the first Community Emergency Response Training (CERT) Program in the United States as a framework for organizing citizens to be more prepared...50 4. How Social Media Influences Volunteers ........................................53 5. The World Wide Web and LAFD CERT

  9. Design and implementation of co-operative control strategy for hybrid AC/DC microgrids

    Mahmud, Rasel

    This thesis is mainly divided in two major sections: 1) Modeling and control of AC microgrid, DC microgrid, Hybrid AC/DC microgrid using distributed co-operative control, and 2) Development of a four bus laboratory prototype of an AC microgrid system. At first, a distributed cooperative control (DCC) for a DC microgrid considering the state-of-charge (SoC) of the batteries in a typical plug-in-electric-vehicle (PEV) is developed. In DC microgrids, this methodology is developed to assist the load sharing amongst the distributed generation units (DGs), according to their ratings with improved voltage regulation. Subsequently, a DCC based control algorithm for AC microgrid is also investigated to improve the performance of AC microgrid in terms of power sharing among the DGs, voltage regulation and frequency deviation. The results validate the advantages of the proposed methodology as compared to traditional droop control of AC microgrid. The DCC-based control methodology for AC microgrid and DC microgrid are further expanded to develop a DCC-based power management algorithm for hybrid AC/DC microgrid. The developed algorithm for hybrid microgrid controls the power flow through the interfacing converter (IC) between the AC and DC microgrids. This will facilitate the power sharing between the DGs according to their power ratings. Moreover, it enables the fixed scheduled power delivery at different operating conditions, while maintaining good voltage regulation and improved frequency profile. The second section provides a detailed explanation and step-by-step design and development of an AC/DC microgrid testbed. Controllers for the three-phase inverters are designed and tested on different generation units along with their corresponding inductor-capacitor-inductor (LCL) filters to eliminate the switching frequency harmonics. Electric power distribution line models are developed to form the microgrid network topology. Voltage and current sensors are placed in the proper

  10. Microgrid testbeds around the world: State of art

    Hossain, Eklas; Kabalci, Ersan; Bayindir, Ramazan; Perez, Ronald

    2014-01-01

    Highlights: • A detail discussion on microgrid project around the world such as North American, Europe, and Japan. • Key benefits of microgrid, issues with on-site generation, features. • Why we need distributed generation system with a brief introduction. • Distributed generation technologies with cost analysis. • The overview on existing distribution network. - Abstract: This paper deals with the recent evolution of microgrids being used around the world in real life applications as well as laboratory application for research. This study is intended to introduce the subject by reviewing the components level, structure and types of microgrid applications installed as a plant or modeled as a simulation environment. The paper also presents a survey regarding published papers on why the microgrid is required, and what the components and control systems are which constitute the actual microgrid studies. It leads the researcher to see the microgrid in terms of the actual bigger picture of today and creates a new outlook about the potential developments. Additionally, comparison of microgrids in various regions based on several parameters allows researchers to define the required criteria and features of a special microgrid that is chosen for a particular scenario. The authors of this paper also tabulated all the necessary information about microgrids, and proposed a standard microgrid for better power quality and optimizing energy generation. Consequently, it is focused on inadequate knowledge and technology gaps in the power system field with regards to the future, and it is this which has been illustrated for the reader. The existing microgrid testbeds all around the world have been studied and analyzed and several of them are explained as an example in this study. Later, those investigated distribution systems are classified based on region (North America, Europe and Asia) and, as presented in literature, a significant amount of deviation has been found

  11. Real-Time Implementation of Islanded Microgrid for Remote Areas

    Monika Jain

    2016-01-01

    Full Text Available Islanding is a condition in which a microgrid or a portion of power grid, consisting of distributed generation (DG sources, converter, and load, gets disconnected from the utility grid. Under this condition the DG sources in a microgrid must switch to a voltage control mode, in order to provide constant voltage to local loads. In grid connected mode, the microgrid works as current controller and injects power to the main grid, depending on the power generation and local load with suitable market policies. Providing constant voltage at a stable frequency with proper synchronization amongst each DG in a microgrid is a challenge. The complexity of such grid requires careful study and analysis before actual implementation. These challenges of microgrid are addressed using real time OPAL-RT simulation technology. Thus the paper describes an islanded microgrid with master slave controller for power balance, voltage/frequency regulation, and synchronization. Based on an advanced real-time platform named Real-Time Laboratory (RT-LAB, the impacts of the micro sources, load, and converters in an islanded microgrid is studied in this paper. The effectiveness of the proposed controller is analyzed through experimental results under balanced/unbalanced nonlinear loads condition.

  12. Microgrid Analysis Tools Summary

    Jimenez, Antonio [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Haase, Scott G [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mathur, Shivani [Formerly NREL

    2018-03-05

    The over-arching goal of the Alaska Microgrid Partnership is to reduce the use of total imported fuel into communities to secure all energy services by at least 50% in Alaska's remote microgrids without increasing system life cycle costs while also improving overall system reliability, security, and resilience. One goal of the Alaska Microgrid Partnership is to investigate whether a combination of energy efficiency and high-contribution (from renewable energy) power systems can reduce total imported energy usage by 50% while reducing life cycle costs and improving reliability and resiliency. This presentation provides an overview of the following four renewable energy optimization tools. Information is from respective tool websites, tool developers, and author experience. Distributed Energy Resources Customer Adoption Model (DER-CAM) Microgrid Design Toolkit (MDT) Renewable Energy Optimization (REopt) Tool Hybrid Optimization Model for Electric Renewables (HOMER).

  13. Urban micro-grids

    Faure, Maeva; Salmon, Martin; El Fadili, Safae; Payen, Luc; Kerlero, Guillaume; Banner, Arnaud; Ehinger, Andreas; Illouz, Sebastien; Picot, Roland; Jolivet, Veronique; Michon Savarit, Jeanne; Strang, Karl Axel

    2017-02-01

    ENEA Consulting published the results of a study on urban micro-grids conducted in partnership with the Group ADP, the Group Caisse des Depots, ENEDIS, Omexom, Total and the Tuck Foundation. This study offers a vision of the definition of an urban micro-grid, the value brought by a micro-grid in different contexts based on real case studies, and the upcoming challenges that micro-grid stakeholders will face (regulation, business models, technology). The electric production and distribution system, as the backbone of an increasingly urbanized and energy dependent society, is urged to shift towards a more resilient, efficient and environment-friendly infrastructure. Decentralisation of electricity production into densely populated areas is a promising opportunity to achieve this transition. A micro-grid enhances local production through clustering electricity producers and consumers within a delimited electricity network; it has the ability to disconnect from the main grid for a limited period of time, offering an energy security service to its customers during grid outages for example. However: The islanding capability is an inherent feature of the micro-grid concept that leads to a significant premium on electricity cost, especially in a system highly reliant on intermittent electricity production. In this case, a smart grid, with local energy production and no islanding capability, can be customized to meet relevant sustainability and cost savings goals at lower costs For industrials, urban micro-grids can be economically profitable in presence of high share of reliable energy production and thermal energy demand micro-grids face strong regulatory challenges that should be overcome for further development Whether islanding is or is not implemented into the system, end-user demand for a greener, more local, cheaper and more reliable energy, as well as additional services to the grid, are strong drivers for local production and consumption. In some specific cases

  14. CERT tribal internship program. Final intern report: Karen Sandoval, 1994

    NONE

    1998-09-01

    The purpose of the project was to: create a working relationship between CERT and Colorado State University (CSU); involve and create relationships among individuals and departments at CSU; empower Native communities to run their own affairs; establish programs for the benefit of Tribes; and create Native American Program Development Office at CSU. The intern lists the following as the project results: revised a Native American Program Development document; confirmation from 45 departments across campus for Summit attendance [Tribal Human Resource Development Summit]; created initial invitee list from CSU departments and colleges; and informed CERT and CSU staff of results. Much of the response from the campus community has been positive and enthusiastic. They are ready to develop new Native American programs on campus, but need the awareness of what they can do to be respectful of Tribal needs.

  15. Testing First-Order Logic Axioms in AutoCert

    Ahn, Ki Yung; Denney, Ewen

    2009-01-01

    AutoCert [2] is a formal verification tool for machine generated code in safety critical domains, such as aerospace control code generated from MathWorks Real-Time Workshop. AutoCert uses Automated Theorem Provers (ATPs) [5] based on First-Order Logic (FOL) to formally verify safety and functional correctness properties of the code. These ATPs try to build proofs based on user provided domain-specific axioms, which can be arbitrary First-Order Formulas (FOFs). These axioms are the most crucial part of the trusted base, since proofs can be submitted to a proof checker removing the need to trust the prover and AutoCert itself plays the part of checking the code generator. However, formulating axioms correctly (i.e. precisely as the user had really intended) is non-trivial in practice. The challenge of axiomatization arise from several dimensions. First, the domain knowledge has its own complexity. AutoCert has been used to verify mathematical requirements on navigation software that carries out various geometric coordinate transformations involving matrices and quaternions. Axiomatic theories for such constructs are complex enough that mistakes are not uncommon. Second, adjusting axioms for ATPs can add even more complexity. The axioms frequently need to be modified in order to have them in a form suitable for use with ATPs. Such modifications tend to obscure the axioms further. Thirdly, speculating validity of the axioms from the output of existing ATPs is very hard since theorem provers typically do not give any examples or counterexamples.

  16. Computing architecture for autonomous microgrids

    Goldsmith, Steven Y.

    2015-09-29

    A computing architecture that facilitates autonomously controlling operations of a microgrid is described herein. A microgrid network includes numerous computing devices that execute intelligent agents, each of which is assigned to a particular entity (load, source, storage device, or switch) in the microgrid. The intelligent agents can execute in accordance with predefined protocols to collectively perform computations that facilitate uninterrupted control of the .

  17. Pyramid solar micro-grid

    Huang, Bin-Juine; Hsu, Po-Chien; Wang, Yi-Hung; Tang, Tzu-Chiao; Wang, Jia-Wei; Dong, Xin-Hong; Hsu, Hsin-Yi; Li, Kang; Lee, Kung-Yen

    2018-03-01

    A novel pyramid solar micro-grid is proposed in the present study. All the members within the micro-grid can mutually share excess solar PV power each other through a binary-connection hierarchy. The test results of a 2+2 pyramid solar micro-grid consisting of 4 individual solar PV systems for self-consumption are reported.

  18. CERT tribal internship program. Final intern report: Maria Perez, 1994

    NONE

    1998-09-01

    Historically, American Indian Tribes have lacked sufficient numbers of trained, technical personnel from their communities to serve their communities; tribal expertise in the fields of science, business and engineering being extremely rare and programs to encourage these disciplines almost non-existent. Subsequently, Tribes have made crucial decisions about their land and other facets of Tribal existence based upon outside technical expertise, such as that provided by the United States government and/or private industries. These outside expert opinions rarely took into account the traditional and cultural values of the Tribes being advised. The purpose of this internship was twofold: Create and maintain a working relationship between CERT and Colorado State University (CSU) to plan for the Summit on Tribal human resource development; and Evaluate and engage in current efforts to strengthen the Tribal Resource Institute in Business, Engineering and Science (TRIBES) program. The intern lists the following as the project results: Positive interactions and productive meetings between CERT and CSU; Gathered information from Tribes; CERT database structure modification; Experience as facilitator in participating methods; Preliminary job descriptions for staff of future TRIBES programs; and Additions for the intern`s personal database of professional contacts and resources.

  19. Methodology for Preliminary Design of Electrical Microgrids

    Jensen, Richard P. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Stamp, Jason E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Eddy, John P. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Henry, Jordan M [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Munoz-Ramos, Karina [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Abdallah, Tarek [U.S. Army Corps of Engineers, Washington, DC (United States)

    2015-09-30

    Many critical loads rely on simple backup generation to provide electricity in the event of a power outage. An Energy Surety Microgrid TM can protect against outages caused by single generator failures to improve reliability. An ESM will also provide a host of other benefits, including integration of renewable energy, fuel optimization, and maximizing the value of energy storage. The ESM concept includes a categorization for microgrid value proposi- tions, and quantifies how the investment can be justified during either grid-connected or utility outage conditions. In contrast with many approaches, the ESM approach explic- itly sets requirements based on unlikely extreme conditions, including the need to protect against determined cyber adversaries. During the United States (US) Department of Defense (DOD)/Department of Energy (DOE) Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) effort, the ESM methodology was successfully used to develop the preliminary designs, which direct supported the contracting, construction, and testing for three military bases. Acknowledgements Sandia National Laboratories and the SPIDERS technical team would like to acknowledge the following for help in the project: * Mike Hightower, who has been the key driving force for Energy Surety Microgrids * Juan Torres and Abbas Akhil, who developed the concept of microgrids for military installations * Merrill Smith, U.S. Department of Energy SPIDERS Program Manager * Ross Roley and Rich Trundy from U.S. Pacific Command * Bill Waugaman and Bill Beary from U.S. Northern Command * Melanie Johnson and Harold Sanborn of the U.S. Army Corps of Engineers Construc- tion Engineering Research Laboratory * Experts from the National Renewable Energy Laboratory, Idaho National Laboratory, Oak Ridge National Laboratory, and Pacific Northwest National Laboratory

  20. Microgrids research: A review of experimental microgrids and test systems

    Lidula, N.W.A.; Rajapakse, A.D. [Department of Electrical and Computer Engineering, 75A Chancellor' s Circle, University of Manitoba, Winnipeg, Manitoba R3T 5V6 (Canada)

    2011-01-15

    A microgrid is particularly a portion of the power distribution system that comprises distributed generation, energy storage and loads. To be capable of operating in parallel to the grid, as an autonomous power island and in transition modes, microgrids must be robust in controlling the local voltage and frequency, and protecting the network and equipment connected to the microgrid. It also needs to facilitate demand side management and resynchronization. This paper presents a review of existing microgrid test networks around the world (North America, Europe and Asia) and some significantly different microgrid simulation networks present in the literature. Paper is focused on the test systems and available microgrid control options. A summary table comparing and contrasting the existing test systems is presented. The paper is concluded highlighting the worthy findings and possible areas of research that would enhance practical use of microgrid facilities. (author)

  1. Energy storage for sustainable microgrid

    Gao, David Wenzhong

    2015-01-01

    Energy Storage for Sustainable Microgrid addresses the issues related to modelling, operation and control, steady-state and dynamic analysis of microgrids with ESS. This book discusses major electricity storage technologies in depth along with their efficiency, lifetime cycles, environmental benefits and capacity, so that readers can envisage which type of storage technology is best for a particular microgrid application. This book offers solutions to numerous difficulties such as choosing the right ESS for the particular microgrid application, proper sizing of ESS for microgrid, as well as

  2. Integration& Operation of a Microgrid at Santa Rita Jail

    Chevron Energy Solutions; Alameda County; DeForest, Nicholas; Lai, Judy; Stadler, Michael; Mendes, Goncalo; Marnay, Chris; Donadee, Jon

    2011-05-01

    Santa Rita Jail is a 4,500 inmate facility located in Dublin CA, approximately 40 miles (65 km) east of San Francisco. Over the past decade, a series of Distributed Energy Resources (DER) installations and efficiency measures have been undertaken to transform the 3MW facility into a"Green Jail". These include a 1.2MW rated rooftop PV system installed in 2002, a 1MW molten carbonate fuel cell with CHP, and retrofits to lighting and HVAC systems to reduce peak loads. With the upcoming installation of a large-scale battery and fast static disconnect switch, Santa Rita Jail will become a true microgrid, with full CERTS Microgrid functionality. Consequently, the jail will be able to seamlessly disconnect from the grid and operate as an island in the event of a disturbance, reconnecting again once the disturbance has dissipated. The extent to which that jail is capable of islanding is principally dependant on the energy capacity of the battery-one focus of this investigation. Also presented here are overviews of the DER currently installed at the jail, as well as the value it provides by offsetting the purchase of electricity under the current Pacific Gas& Electric (PG&E) tariff.

  3. Energy centre microgrid model

    Pasonen, R.

    2011-09-15

    A simulation model of Energy centre microgrid made with PSCAD simulation software version 4.2.1 has been built in SGEM Smart Grids and Energy Markets (SGEM) work package 6.6. Microgrid is an autonomous electric power system which can operate separate from common distribution system. The idea of energy centre microgrid concept was considered in Master of Science thesis 'Community Microgrid - A Building block of Finnish Smart Grid'. The name of energy centre microgrid comes from a fact that production and storage units are concentrated into a single location, an energy centre. This centre feeds the loads which can be households or industrial loads. Power direction flow on the demand side remains same compared to the current distribution system and allows to the use of standard fuse protection in the system. The model consists of photovoltaic solar array, battery unit, variable frequency boost converter, inverter, isolation transformer and demand side (load) model. The model is capable to automatically switch to islanded mode when there is a fault in outside grid and back to parallel operation mode when fault is removed. The modelled system responses well to load changes and total harmonic distortion related to 50Hz base frequency is kept under 1.5% while operating and feeding passive load. (orig.)

  4. Effect of Heat and Electricity Storage and Reliability on Microgrid Viability: A Study of Commercial Buildings in California and New York States

    Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy; Coffey, Brian; Aki, Hirohisa

    2009-03-10

    Berkeley Lab has for several years been developing methods for selection of optimal microgrid systems, especially for commercial building applications, and applying these methods in the Distributed Energy Resources Customer Adoption Model (DER-CAM). This project began with 3 major goals: (1) to conduct detailed analysis to find the optimal equipment combination for microgrids at a few promising commercial building hosts in the two favorable markets of California and New York, (2) to extend the analysis capability of DER-CAM to include both heat and electricity storage, and (3) to make an initial effort towards adding consideration of power quality and reliability (PQR) to the capabilities of DER-CAM. All of these objectives have been pursued via analysis of the attractiveness of a Consortium for Electric Reliability Technology Solutions (CERTS) Microgrid consisting of multiple nameplate 100 kW Tecogen Premium Power Modules (CM-100). This unit consists of an asynchronous inverter-based variable speed internal combustion engine genset with combined heat and power (CHP) and power surge capability. The essence of CERTS Microgrid technology is that smarts added to the on-board power electronics of any microgrid device enables stable and safe islanded operation without the need for complex fast supervisory controls. This approach allows plug and play development of a microgrid that can potentially provide high PQR with a minimum of specialized site-specific engineering. A notable feature of the CM-100 is its time-limited surge rating of 125 kW, and DER-CAM capability to model this feature was also a necessary model enhancement.

  5. CERT depletion predicts chemotherapy benefit and mediates cytotoxic and polyploid‐specific cancer cell death through autophagy induction

    Lee, Alvin J. X.; Roylance, Rebecca; Sander, Jil

    2012-01-01

    cell microscopy analysis revealed that CERT depletion induces LAMP2‐dependent death of polyploid cells following exit from mitosis in the presence of paclitaxel. We find that CERT is relatively over‐expressed in HER2+ breast cancer and CERT protein expression acts as an independent prognostic variable...

  6. Hybrid Shipboard Microgrids

    Othman @ Marzuki, Muzaidi Bin; Anvari-Moghaddam, Amjad; Guerrero, Josep M.

    2017-01-01

    Strict regulation on emissions of air pollutants imposed by the maritime authorities has led to the introduction of hybrid microgrids to the shipboard power systems (SPSs) which acts toward energy efficient ships with less pollution. A hybrid energy system can include different means of generation...

  7. Radiochromic film dosimetry of contrast-enhanced radiotherapy (CERT)

    Morris, Kevin N; Weil, Michael D; Malzbender, Rainer

    2006-01-01

    Contrast-enhanced radiotherapy (CERT) employs elevated concentrations of high-Z contrast media in targets to dramatically increase the absorbed dose of radiation relative to the surrounding tissues. However, it is difficult to measure the dose enhancement with routine clinical instruments because the photoelectrons and Auger electrons produced by the interaction of kilovoltage x-rays with the contrast agent travel extremely short distances. We have developed a technique utilizing unlaminated radiochromic film to measure the maximum dose enhancement factor attainable in solutions of contrast agent with iodine concentrations ranging from 0% to 37% (w/v). The films were also used to simultaneously measure the dose enhancement and beam attenuation through solutions containing 0%, 5% and 10% iodine (w/v). These depth-dose measurements were made in phantoms representing 3 cm targets located 0 and 4.8 cm deep in acrylic. Higher concentrations of contrast yielded greater dose enhancement and target-to-surface dose ratios, but caused more rapid attenuation of the beam as it traversed the target. The dose distribution across the entire target could be improved by employing multiple beams. These results, using concentrations of contrast that are clinically achievable by intratumoural injection, illustrate the potential of CERT for the specific delivery of high doses of radiation to targets at depth

  8. System and method for controlling microgrid

    Bose, Sumit [Niskayuna, NY; Achilles, Alfredo Sebastian [Bavaria, DE; Liu, Yan [Ballston Lake, NY; Ahmed, Emad Ezzat [Munich, DE; Garces, Luis Jose [Niskayuna, NY

    2011-07-19

    A system for controlling a microgrid includes microgrid assets and a tieline for coupling the microgrid to a bulk grid; and a tieline controller coupled to the tieline. At least one of the microgrid assets comprises a different type of asset than another one of the microgrid assets. The tieline controller is configured for providing tieline control signals to adjust active and reactive power in respective microgrid assets in response to commands from the bulk grid operating entity, microgrid system conditions, bulk grid conditions, or combinations thereof.

  9. Renewable Microgrid STEM Education & Colonias Outreach Program

    None, None

    2015-04-01

    To provide Science, Technology, Engineering, and Math (STEM) outreach and education to secondary students to encourage them to select science and engineering as a career by providing an engineering-based problem-solving experience involving renewable energy systems such as photovoltaic (PV) panels or wind turbines. All public and private schools, community colleges, and vocational training programs would be eligible for participation. The Power Microgrids High School Engineering Experience used renewable energy systems (PV and wind) to provide a design capstone experience to secondary students. The objective for each student team was to design a microgrid for the student’s school using renewable energy sources under cost, schedule, performance, and risk constraints. The students then implemented their designs in a laboratory environment to evaluate the completeness of the proposed design, which is a unique experience even for undergraduate college students. This application-based program was marketed to secondary schools in the 28th Congressional District through the Texas Education Agency’s (TEA) Regional Service Centers. Upon application, TEES identified regionally available engineers to act as mentors and supervisors for the projects. Existing curriculum was modified to include microgrid and additional renewable technologies and was made available to the schools.

  10. CERTS: Consortium for Electric Reliability Technology Solutions - Research Highlights

    Eto, Joseph

    2003-07-30

    Historically, the U.S. electric power industry was vertically integrated, and utilities were responsible for system planning, operations, and reliability management. As the nation moves to a competitive market structure, these functions have been disaggregated, and no single entity is responsible for reliability management. As a result, new tools, technologies, systems, and management processes are needed to manage the reliability of the electricity grid. However, a number of simultaneous trends prevent electricity market participants from pursuing development of these reliability tools: utilities are preoccupied with restructuring their businesses, research funding has declined, and the formation of Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) to operate the grid means that control of transmission assets is separate from ownership of these assets; at the same time, business uncertainty, and changing regulatory policies have created a climate in which needed investment for transmission infrastructure and tools for reliability management has dried up. To address the resulting emerging gaps in reliability R&D, CERTS has undertaken much-needed public interest research on reliability technologies for the electricity grid. CERTS' vision is to: (1) Transform the electricity grid into an intelligent network that can sense and respond automatically to changing flows of power and emerging problems; (2) Enhance reliability management through market mechanisms, including transparency of real-time information on the status of the grid; (3) Empower customers to manage their energy use and reliability needs in response to real-time market price signals; and (4) Seamlessly integrate distributed technologies--including those for generation, storage, controls, and communications--to support the reliability needs of both the grid and individual customers.

  11. MICROGRIDS: THE AGRIA TEST LOCATION

    Aleksandra Krkoleva

    2010-01-01

    Full Text Available The paper presents the pilot Microgrid in Macedonia, developed within the framework of the MOREMICROGRIDS (EU EP6 projecet, contract No. SES6-019864 project. This Microgrid is the first of its kind being developed in the Western Balkan region and serves as pilot site for introduction and examination of the Microgrids concept in non European Union conditions. The test network consists of a part of the low voltage grid, located on a pig farm. The main electricity source for the Microgrid is a small biogas plant, which uses the biogas produced by a waste water treatment process. The paper addresses the Microgrid design, development of test scenarios and test results from the pilot location.

  12. Smart Metering System for Microgrids

    Palacios-Garcia, Emilio; Guan, Yajuan; Savaghebi, Mehdi

    2015-01-01

    suppliers, but they can also play a big role in the control of the Microgrid since the recorded power and energy profiles can be integrated in energy management systems (EMS). In addition, basic power quality (PQ) disturbance can de detected and reported by some advanced metering systems. Thus, this paper...... will expose an example of Smart Meters integration in a Microgrid scenario, which is the Intelligent Microgrid Lab of Aalborg University (AAU). To do this, first the installation available in the Microgrid Lab will be introduced. Then, three different test scenarios and their respective results...... will be presented, regarding the capabilities of this system and the advantages of integration the Smart Meters information in the Microgrid control....

  13. Applying DER-CAM for IIT Microgrid Explansion Planning

    Shahidehpour, Mohammad [Illinois Inst. of Technology, Chicago, IL (United States); Li, Zuyi [Illinois Inst. of Technology, Chicago, IL (United States); Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Chen [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-04-19

    The Distributed Energy Resources Customer Adoption Model (DER-CAM) is an economic and environmental model of customer DER adoption. This model has been in development at the Lawrence Berkeley National Laboratory since 2000. The objective of the model is to find optimal DER investments while minimizing total energy costs or carbon dioxide (CO2) emissions, or achieving a weighted objective that simultaneously considers both criteria. The Illinois Institute of Technology (IIT) Microgrid project started in August 2008, and the majority of the project was completed in May 2013. IIT Microgrid, funded mostly by a grant from the U.S. Department of Energy as well as State and philanthropic contributions, empowers the campus consumers with the objective of establishing a smart microgrid that is highly reliable, economically viable, environmentally friendly, fuel-efficient, and resilient in extreme circumstances with a self-healing capability. In this project, we apply DER-CAM to study the expansion planning of the IIT Microgrid. First, the load data, environmental data, utility data, and technology data for the IIT Microgrid are gathered and organized to follow the DER-CAM input requirements. Then, DERCAM is applied to study the expansion planning of the IIT Microgrid for different cases, where different objectives in DER-CAM and different utility conditions are tested. Case 1 considers the objective of minimizing energy costs with fixed utility rates and 100% electric utility availability. Case 2 considers the objective of minimizing energy costs with real-time utility rates and 4 emergency weeks when the IIT Microgrid does not have access to the electric utility grid and has to operate in island mode. In Case 3, the utility rates are restored to fixed values and 100% electric utility availability is assumed, but a weighted multi-objective (Obj: a × costs + b × CO2 emissions, where a and b are weights for cost minimization and CO2 emissions minimization) is utilized to

  14. Review on Control of DC Microgrids and Multiple Microgrid Clusters

    Meng, Lexuan; Shafiee, Qobad; Ferrari-Trecate, Giancarlo

    2017-01-01

    This paper performs an extensive review on control schemes and architectures applied to DC microgrids. It covers multi-layer hierarchical control schemes, coordinated control strategies, plug-and-play operations, stability and active damping aspects as well as nonlinear control algorithms....... Islanding detection, protection and microgrid clusters control are also briefly summarized. All the mentioned issues are discussed with the goal of providing control design guidelines for DC microgrids. The future research challenges, from the authors’ point of view, are also provided in the final...

  15. Adaptive Distance Protection for Microgrids

    Lin, Hengwei; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2015-01-01

    is adopted to accelerate the tripping speed of the relays on the weak lines. The protection methodology is tested on a mid-voltage microgrid network in Aalborg, Denmark. The results show that the adaptive distance protection methodology has good selectivity and sensitivity. What is more, this system also has......Due to the increasing penetration of distributed generation resources, more and more microgrids can be found in distribution systems. This paper proposes a phasor measurement unit based distance protection strategy for microgrids in distribution system. At the same time, transfer tripping scheme...

  16. Power Electronics for Microgrids

    Dragicevic, Tomislav; Blaabjerg, Frede

    2016-01-01

    A microgrid (MG) is a stand-alone or grid-connected hybrid renewable system that uses distributed renewable and nonrenewable energy sources and energy storage systems (ESSs) to supply power to local loads. The system is ordinarily based on power electronics, with interface converters allowing...... a continuous supply of power in the presence of variable RES production. This chapter describes some specific features of DC MGs in terms of power architecture, control, and protection. It also reviews several uncommon power electronic interfaces. Regarding control, operation without critical communication...... are explained in this chapter. The chapter concludes with a review of power electronic intensive protection solutions for DC MGs....

  17. Lessons Learned from Microgrid Demonstrations Worldwide

    Marnay, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Qu, Min [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Romankiewicz, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-01-31

    The survey leads to policy recommendations for starting a microgrid demonstration program and overall development of microgrid and distributed energy. Additionally, specific recommendations have been made for China specifically.

  18. Analysis and Application of Microgrids

    Yue, Lu

    New trends of generating electricity locally and utilizing non-conventional or renewable energy sources have attracted increasing interests due to the gradual depletion of conventional fossil fuel energy sources. The new type of power generation is called Distributed Generation (DG) and the energy sources utilized by Distributed Generation are termed Distributed Energy Sources (DERs). With DGs embedded in the distribution networks, they evolve from passive distribution networks to active distribution networks enabling bidirectional power flows in the networks. Further incorporating flexible and intelligent controllers and employing future technologies, active distribution networks will turn to a Microgrid. A Microgrid is a small-scale, low voltage Combined with Heat and Power (CHP) supply network designed to supply electrical and heat loads for a small community. To further implement Microgrids, a sophisticated Microgrid Management System must be integrated. However, due to the fact that a Microgrid has multiple DERs integrated and is likely to be deregulated, the ability to perform real-time OPF and economic dispatch with fast speed advanced communication network is necessary. In this thesis, first, problems such as, power system modelling, power flow solving and power system optimization, are studied. Then, Distributed Generation and Microgrid are studied and reviewed, including a comprehensive review over current distributed generation technologies and Microgrid Management Systems, etc. Finally, a computer-based AC optimization method which minimizes the total transmission loss and generation cost of a Microgrid is proposed and a wireless communication scheme based on synchronized Code Division Multiple Access (sCDMA) is proposed. The algorithm is tested with a 6-bus power system and a 9-bus power system.

  19. Improving Distribution Resiliency with Microgrids and State and Parameter Estimation

    Tuffner, Francis K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Tess L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schneider, Kevin P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sun, Yannan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Chen-Ching [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Yin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gourisetti, Sri Nikhil Gup [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-09-30

    Modern society relies on low-cost reliable electrical power, both to maintain industry, as well as provide basic social services to the populace. When major disturbances occur, such as Hurricane Katrina or Hurricane Sandy, the nation’s electrical infrastructure can experience significant outages. To help prevent the spread of these outages, as well as facilitating faster restoration after an outage, various aspects of improving the resiliency of the power system are needed. Two such approaches are breaking the system into smaller microgrid sections, and to have improved insight into the operations to detect failures or mis-operations before they become critical. Breaking the system into smaller sections of microgrid islands, power can be maintained in smaller areas where distribution generation and energy storage resources are still available, but bulk power generation is no longer connected. Additionally, microgrid systems can maintain service to local pockets of customers when there has been extensive damage to the local distribution system. However, microgrids are grid connected a majority of the time and implementing and operating a microgrid is much different than when islanded. This report discusses work conducted by the Pacific Northwest National Laboratory that developed improvements for simulation tools to capture the characteristics of microgrids and how they can be used to develop new operational strategies. These operational strategies reduce the cost of microgrid operation and increase the reliability and resilience of the nation’s electricity infrastructure. In addition to the ability to break the system into microgrids, improved observability into the state of the distribution grid can make the power system more resilient. State estimation on the transmission system already provides great insight into grid operations and detecting abnormal conditions by leveraging existing measurements. These transmission-level approaches are expanded to using

  20. Microgrid cyber security reference architecture.

    Veitch, Cynthia K.; Henry, Jordan M.; Richardson, Bryan T.; Hart, Derek H.

    2013-07-01

    This document describes a microgrid cyber security reference architecture. First, we present a high-level concept of operations for a microgrid, including operational modes, necessary power actors, and the communication protocols typically employed. We then describe our motivation for designing a secure microgrid; in particular, we provide general network and industrial control system (ICS)-speci c vulnerabilities, a threat model, information assurance compliance concerns, and design criteria for a microgrid control system network. Our design approach addresses these concerns by segmenting the microgrid control system network into enclaves, grouping enclaves into functional domains, and describing actor communication using data exchange attributes. We describe cyber actors that can help mitigate potential vulnerabilities, in addition to performance bene ts and vulnerability mitigation that may be realized using this reference architecture. To illustrate our design approach, we present a notional a microgrid control system network implementation, including types of communica- tion occurring on that network, example data exchange attributes for actors in the network, an example of how the network can be segmented to create enclaves and functional domains, and how cyber actors can be used to enforce network segmentation and provide the neces- sary level of security. Finally, we describe areas of focus for the further development of the reference architecture.

  1. Equivalent Simplification Method of Micro-Grid

    Cai Changchun; Cao Xiangqin

    2013-01-01

    The paper concentrates on the equivalent simplification method for the micro-grid system connection into distributed network. The equivalent simplification method proposed for interaction study between micro-grid and distributed network. Micro-grid network, composite load, gas turbine synchronous generation, wind generation are equivalent simplification and parallel connect into the point of common coupling. A micro-grid system is built and three phase and single phase grounded faults are per...

  2. Design and Implementation of a Control Strategy for Microgrid Containing Renewable Energy Generations and Electric Vehicles

    Mingchao Xia

    2013-01-01

    Full Text Available Large amount of such renewable energy generations as wind/photovoltaic generations directly connected to grid acting as distributed generations will cause control, protection, security, and safety problems. Microgrid, which has advantages in usage and control of distributed generations, is a promising approach to coordinate the conflict between distributed generations and the grid. Regarded as mobile power storages, batteries of electric vehicles can depress the fluctuation of power through the point of common coupling of microgrid. This paper presents a control strategy for microgrid containing renewable energy generations and electric vehicles. The control strategy uses current control for renewable energy generations under parallel-to-grid mode, and uses master-slave control under islanding mode. Simulations and laboratory experiments prove that the control strategy works well for microgrid containing renewable energy generations and electric vehicles and provides maximum power output of renewable energy and a stable and sustainable running under islanding mode.

  3. Power Systems Integration Laboratory | Energy Systems Integration Facility

    | NREL Power Systems Integration Laboratory Power Systems Integration Laboratory Research in the Energy System Integration Facility's Power Systems Integration Laboratory focuses on the microgrid applications. Photo of engineers testing an inverter in the Power Systems Integration Laboratory

  4. Advanced Control Architectures for Intelligent MicroGrids, Part I

    Guerrero, Josep M.; Chandorkar, Mukul; Lee, Tzung-Lin

    2013-01-01

    This paper presents a review of advanced control techniques for microgrids. The paper covers decentralized, distributed, and hierarchical control of grid connected and islanded microgrids. At first, decentralized control techniques for microgrids are reviewed. Then, the recent developments in the...

  5. Microgrid central controller development and hierarchical control implemetation in the intelligent microgrid lab of Aalborg University

    Meng, Lexuan; Savaghebi, Mehdi; Andrade, Fabio; Vasquez Quintero, Juan Carlos; Guerrero, Josep M.; Graells Sobré, Moisès

    2015-01-01

    This paper presents the development of a microgrid central controller in an inverter-based intelligent microgrid (iMG) lab in Aalborg University, Denmark. The iMG lab aims to provide a flexible experimental platform for comprehensive studies of microgrids. The complete control system applied in this lab is based on the hierarchical control scheme for microgrids and includes primary, secondary and tertiary control. The structure of the lab, including the lab facilities, configurations and comm...

  6. Value Streams in Microgrids: A literature Review

    Stadler, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Center for Energy and Innovative Technologies (CET) (Austria); Cardoso, Gonçalo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mashayekh, Salman [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Forget, Thibault [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); MINES Paris Tech. (France); DeForest, Nicholas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Agarwal, Ankit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Schönbein, Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of Freiburg (Germany)

    2015-10-01

    Microgrids are an increasingly common component of the evolving electricity grids with the potential to improve local reliability, reduce costs, and increase penetration rates for distributed renewable generation. The additional complexity of microgrids often leads to increased investment costs, creating a barrier for widespread adoption. These costs may result directly from specific needs for islanding detection, protection systems and power quality assurance that would otherwise be avoided in simpler system configurations. However, microgrids also facilitate additional value streams that may make up for their increased costs and improve the economic viability of microgrid deployment. This paper analyses the literature currently available on research relevant to value streams occurring in microgrids that may contribute to offset the increased investment costs. A review on research related to specific microgrid requirements is also presented.

  7. Secure Automated Microgrid Energy System

    2016-12-01

    O&M Operations and Maintenance PSO Power System Optimization PV Photovoltaic RAID Redundant Array of Independent Disks RBAC Role...elements of the initial study and operational power system model (feeder size , protective devices, generation sources, controllable loads, transformers...EW-201340) Secure Automated Microgrid Energy System December 2016 This document has been cleared for public release; Distribution Statement A

  8. Energy manager design for microgrids

    Firestone, Ryan; Marnay, Chris

    2005-01-01

    On-site energy production, known as distributed energy resources (DER), offers consumers many benefits, such as bill savings and predictability, improved system efficiency, improved reliability, control over power quality, and in many cases, greener electricity. Additionally, DER systems can benefit electric utilities by reducing congestion on the grid, reducing the need for new generation and transmission capacity, and offering ancillary services such as voltage support and emergency demand response. Local aggregations of distributed energy resources (DER) that may include active control of on-site end-use energy devices can be called microgrids. Microgrids require control to ensure safe operation and to make dispatch decisions that achieve system objectives such as cost minimization, reliability, efficiency and emissions requirements, while abiding by system constraints and regulatory rules. This control is performed by an energy manager (EM). Preferably, an EM will achieve operation reasonably close to the attainable optimum, it will do this by means robust to deviations from expected conditions, and it will not itself incur insupportable capital or operation and maintenance costs. Also, microgrids can include supervision over end-uses, such as curtailing or rescheduling certain loads. By viewing a unified microgrid as a system of supply and demand, rather than simply a system of on-site generation devices, the benefits of integrated supply and demand control can be exploited, such as economic savings and improved system energy efficiency

  9. Control of grid interactive AC microgrids

    Wang, Xiongfei; Guerrero, Josep M.; Chen, Zhe

    2010-01-01

    Over the last decade, distributed energy resources (DER) technology has undergone a fast development. Increased penetration of DER units and wide spread use of renewable energy sources challenge the entire architecture of traditional power system. Microgrid, characterizing higher flexibility......, microgrid controls and power management strategies are presented. Future trends of microgrid are discussed pointing out how this concept can be a key to achieve a more intelligent and flexible AC grid....

  10. Developing Efficient Urban Electrical Systems Using Microgrids

    Gahagan, Michael

    2010-09-15

    Electric vehicles and battery storage will complicate utility operations and strain existing networks. One possible solution is the implementation of 'microgrids' autonomous electricity environments that operate within a larger electric utility grid and their 'controllers' Microgrids direct locally generated power to local demand, coordinate with centralized utility networks to meet additional demand, and pass excess supply to neighboring microgrids. This paper explains the evolution of microgrids. It details their design and operation. It also reviews their many benefits within urban settings, including minimizing customer costs while maximizing use of local generation from clean, renewable resources.

  11. Networked control of microgrid system of systems

    Mahmoud, Magdi S.; Rahman, Mohamed Saif Ur; AL-Sunni, Fouad M.

    2016-08-01

    The microgrid has made its mark in distributed generation and has attracted widespread research. However, microgrid is a complex system which needs to be viewed from an intelligent system of systems perspective. In this paper, a network control system of systems is designed for the islanded microgrid system consisting of three distributed generation units as three subsystems supplying a load. The controller stabilises the microgrid system in the presence of communication infractions such as packet dropouts and delays. Simulation results are included to elucidate the effectiveness of the proposed control strategy.

  12. Microgrid Plant Control Design and Development

    Wiegman, Herman [GE Global Research, Niskayuna, New York (United States); Baone, Chaitanya [GE Global Research, Niskayuna, New York (United States)

    2017-08-14

    This report discusses the technical performance of the proposed microgrid at Potsdam, New York, and the enhanced microgrid controller platform. The test objectives were outlined by the DOE, and summary results and discussion are given for each objective. The findings show that the proposed Potsdam, NY microgrid would have a significant impact on the regional CO2 emissions, the amount of imported energy from the utility, and the resiliency of the critical loads. Additionally, the enhanced microgrid control system developed for this project was tested to be compliant with IEEE 1547 standards, and able to generate revenues to help offset energy costs by way of participation in ancillary services.

  13. Energy Systems Integration Laboratory | Energy Systems Integration Facility

    | NREL Integration Laboratory Energy Systems Integration Laboratory Research in the Energy Systems Integration Laboratory is advancing engineering knowledge and market deployment of hydrogen technologies. Applications include microgrids, energy storage for renewables integration, and home- and station

  14. Microgrid Design Analysis Using Technology Management Optimization and the Performance Reliability Model

    Stamp, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eddy, John P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jensen, Richard P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Munoz-Ramos, Karina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    Microgrids are a focus of localized energy production that support resiliency, security, local con- trol, and increased access to renewable resources (among other potential benefits). The Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) Joint Capa- bility Technology Demonstration (JCTD) program between the Department of Defense (DOD), Department of Energy (DOE), and Department of Homeland Security (DHS) resulted in the pre- liminary design and deployment of three microgrids at military installations. This paper is focused on the analysis process and supporting software used to determine optimal designs for energy surety microgrids (ESMs) in the SPIDERS project. There are two key pieces of software, an ex- isting software application developed by Sandia National Laboratories (SNL) called Technology Management Optimization (TMO) and a new simulation developed for SPIDERS called the per- formance reliability model (PRM). TMO is a decision support tool that performs multi-objective optimization over a mixed discrete/continuous search space for which the performance measures are unrestricted in form. The PRM is able to statistically quantify the performance and reliability of a microgrid operating in islanded mode (disconnected from any utility power source). Together, these two software applications were used as part of the ESM process to generate the preliminary designs presented by SNL-led DOE team to the DOD. Acknowledgements Sandia National Laboratories and the SPIDERS technical team would like to acknowledge the following for help in the project: * Mike Hightower, who has been the key driving force for Energy Surety Microgrids * Juan Torres and Abbas Akhil, who developed the concept of microgrids for military instal- lations * Merrill Smith, U.S. Department of Energy SPIDERS Program Manager * Ross Roley and Rich Trundy from U.S. Pacific Command * Bill Waugaman and Bill Beary from U.S. Northern Command * Tarek Abdallah, Melanie

  15. Impact of Faults and Protection Methods on DC Microgrids Operation

    Bayati, Navid; Hajizadeh, Amin; N. Soltani, Mohsen

    2018-01-01

    with the DC Microgrid. This paper evaluates and presents a comprehensive review on the most recent studies in the DC Microgrids protection. Moreover, the fault behavior and characteristics of DC Microgrids, the effect of Constant Power Load (CPL) , and recent DC Microgrid protection methods are reviewed. Also...

  16. A New Seamless Transfer Control Strategy of the Microgrid

    Zhang, Zhaoyun; Chen, Wei; Zhang, Zhe

    2014-01-01

    A microgrid may operate under two typical modes; the seamless transfer control of the microgrid is very important. The mode conversion controller is installed in microgrid and the control logic of master power is optimized for microgrid mode conversion. In the proposed scheme, master power is very important. The master-power is under the PQ control when microgrid is under grid-connected. And it is under V/F control when the microgrid is under islanding. The microgrid mode controller is used t...

  17. Application of Autonomous Spacecraft Power Control Technology to Terrestrial Microgrids

    Dever, Timothy P.; Trase, Larry M.; Soeder, James F.

    2014-01-01

    This paper describes the potential of the power campus located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio for microgrid development. First, the benefits provided by microgrids to the terrestrial power grid are described, and an overview of Technology Needs for microgrid development is presented. Next, GRC's work on development of autonomous control for manned deep space vehicles, which are essentially islanded microgrids, is covered, and contribution of each of these developments to the microgrid Technology Needs is detailed. Finally, a description is provided of GRC's existing physical assets which can be applied to microgrid technology development, and a phased plan for development of a microgrid test facility is presented.

  18. Controls for microgrids with storage: Review, challenges, and research needs

    Zamora, Ramon [Department of Electrical and Computer Engineering, Mississippi State University, P O Box 9571, Mississippi State, MS 39762 (United States); Department of Electrical Engineering, Syiah Kuala University, Banda Aceh 23111 (Indonesia); Srivastava, Anurag K. [Department of Electrical and Computer Engineering, Mississippi State University, P O Box 9571, Mississippi State, MS 39762 (United States)

    2010-09-15

    The interest on microgrid has increased significantly triggered by the increasing demand of reliable, secure, efficient, clean, and sustainable electricity. More research and implementation of microgrid will be conducted in order to improve the maturity of microgrid technology. Among different aspects of microgrid, this paper focuses on controls of microgrid with energy storage. A comprehensive review on current control technology is given with a discussion on challenges of microgrid controls. Basic simulation results are also presented to enhance and support the analysis. Finally, research needs and roadmap for microgrid control are also described. (author)

  19. Control principles for blackstart and island operation of microgrid

    Laaksonen, H.; Kauhaniemi, K. (University of Vaasa (Finland))

    2008-07-01

    In some unexpected situations a microgrid may become unstable after transition to islanded mode and all DG units must be disconnected from microgrid. In case of these events a restoration strategy for microgrid blackstart is needed. Also if the islanded microgrid is divided into different protection zones in case of a fault, fault management strategy with capability of very fast operation is needed to maintain stability in the healthy section of the islanded microgrid. The control of microgrid voltage and frequency during the microgrid blackstart is not possible without energy storage unit. In this paper sequence of actions for the microgrid blackstart operation as well as control principles of some DG units during blackstart are defined and simulated with two different microgrid configurations. Also one simulation case considering fault management strategy and control principles during fault in islanded microgrid is presented. Based on the simulations dimensioning principles for the needed energy storage and size of simultaneously controlled loads can be drawn. (orig.)

  20. Kalaeloa Energy System Redevelopment Options Including Advanced Microgrids.

    Hightower, Marion Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Baca, Michael J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); VanderMey, Carissa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-03-01

    In June 2016, the Department of Energy's (DOE's) Office of Energy Efficiency and Renewable Energy (EERE) in collaboration with the Renewable Energy Branch for the Hawaii State Energy Office (HSEO), the Hawaii Community Development Authority (HCDA), the United States Navy (Navy), and Sandia National Laboratories (Sandia) established a project to 1) assess the current functionality of the energy infrastructure at the Kalaeloa Community Development District, and 2) evaluate options to use both existing and new distributed and renewable energy generation and storage resources within advanced microgrid frameworks to cost-effectively enhance energy security and reliability for critical stakeholder needs during both short-term and extended electric power outages. This report discusses the results of a stakeholder workshop and associated site visits conducted by Sandia in October 2016 to identify major Kalaeloa stakeholder and tenant energy issues, concerns, and priorities. The report also documents information on the performance and cost benefits of a range of possible energy system improvement options including traditional electric grid upgrade approaches, advanced microgrid upgrades, and combined grid/microgrid improvements. The costs and benefits of the different improvement options are presented, comparing options to see how well they address the energy system reliability, sustainability, and resiliency priorities identified by the Kalaeloa stakeholders.

  1. Experimental framework for laboratory scale microgrids

    José Alex Restrepo-Zambrano

    2016-01-01

    Full Text Available Este artículo presenta una propuesta de un banco de pruebas de microrredes para uso en laboratorio. El objetivo es proporcionar alta flexibilidad utilizando un enfoque modular con un hardware común para la mayoría de las tareas. El marco experimental propuesto para microrredes a escala de laboratorio proporciona los requisitos para enseñanza e investigación. Esto se logra con una etapa de electrónica de potencia reconfigurable, para pruebas y diseños de nuevas topologías. Permite probar algoritmos en los distintos niveles de la estructura jerárquica de la microrred. Da acceso a la emulación y simulación de elementos encontrados comúnmente en una microrred y a la programación de bajo nivel de los protocolos de comunicación para estudiar el canal de comunicación. La unidad de procesamiento en cada módulo, llamado controlador local, utiliza un procesador digital de señales de alto rendimiento (DSP. Esta unidad de procesamiento permite la reconfiguración de cada módulo para asumir cualquier tarea en la microrred; es decir, como cargas controlables, almacenamiento de energía, generación eólica, generación fotovoltaica, etc. El hardware propuesto se probó operando como emulador de los diferentes subsistemas. Las comunicaciones con un controlador central microrred (MCC se realizan mediante procesadores integrados estándar, capaces de implementar los protocolos de comunicación adecuados para ambientes de microrred.

  2. Model predictive control of smart microgrids

    Hu, Jiefeng; Zhu, Jianguo; Guerrero, Josep M.

    2014-01-01

    The exploitation of renewable energy and the development of intelligent electricity network have become the main concerns worldwide. This paper aims to integrate renewable energy sources, local loads, and energy storage devices into smart microgrids. It proposes a new microgrid configuration...

  3. Microgrids | Energy Systems Integration Facility | NREL

    . Diesel generators: because diesel generators are traditional microgrid components, three different generator sets with various control options are available for microgrid integration efforts. DC power supplies: the ESIF's full suite of DC simulation capability includes a 1.5-MW photovoltaic (PV) simulator

  4. The advanced microgrid. Integration and interoperability

    Bower, Ward Isaac [Ward Bower Innovations, LLC, Albuquerque, NM (United Staes); Ton, Dan T. [U.S. Dept. of Energy, Washington, DC (United States); Guttromson, Ross [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Glover, Steven F [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stamp, Jason Edwin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bhatnagar, Dhruv [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reilly, Jim [Reily Associates, Pittston, PA (United States)

    2014-02-01

    This white paper focuses on "advanced microgrids," but sections do, out of necessity, reference today's commercially available systems and installations in order to clearly distinguish the differences and advances. Advanced microgrids have been identified as being a necessary part of the modern electrical grid through a two DOE microgrid workshops, the National Institute of Standards and Technology, Smart Grid Interoperability Panel and other related sources. With their grid-interconnectivity advantages, advanced microgrids will improve system energy efficiency and reliability and provide enabling technologies for grid-independence to end-user sites. One popular definition that has been evolved and is used in multiple references is that a microgrid is a group of interconnected loads and distributed-energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. A microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or island-mode. Further, an advanced microgrid can then be loosely defined as a dynamic microgrid.

  5. CERT / CSIRT tímy a kybernetická bezpečnosť

    Rezníčková, Dominika

    2014-01-01

    The main goal of this bachelor thesis is to provide brief description of contemporary situation in the field of cyber security and the role of national CERT team in it according to the newly adopted Law no. 181/2014 Coll., on Cyber Security and to make comparison of theoretical principles with their applying in praxis. Thesis is divided into two main parts. First one, a theoretical part, comprehends basic information on cyber security, cybercrime and security incidents and consequently focuse...

  6. Modeling and Control for Microgrids

    Steenis, Joel

    Traditional approaches to modeling microgrids include the behavior of each inverter operating in a particular network configuration and at a particular operating point. Such models quickly become computationally intensive for large systems. Similarly, traditional approaches to control do not use advanced methodologies and suffer from poor performance and limited operating range. In this document a linear model is derived for an inverter connected to the Thevenin equivalent of a microgrid. This model is then compared to a nonlinear simulation model and analyzed using the open and closed loop systems in both the time and frequency domains. The modeling error is quantified with emphasis on its use for controller design purposes. Control design examples are given using a Glover McFarlane controller, gain scheduled Glover McFarlane controller, and bumpless transfer controller which are compared to the standard droop control approach. These examples serve as a guide to illustrate the use of multi-variable modeling techniques in the context of robust controller design and show that gain scheduled MIMO control techniques can extend the operating range of a microgrid. A hardware implementation is used to compare constant gain droop controllers with Glover McFarlane controllers and shows a clear advantage of the Glover McFarlane approach.

  7. Energy-Water Microgrid Case Study at the University of Arizona's BioSphere 2

    Daw, J.; Macknick, J.; Kandt, A.; Giraldez, J.

    2016-12-01

    Microgrids can provide reliable and cost-effective energy services in a variety of conditions and locations. To date, there has been minimal effort invested in developing energy-water microgrids that demonstrate the feasibility and leverage the synergies associated with designing and operating renewable energy and water systems in a coordinated framework. Water and wastewater treatment equipment can be operated in ways to provide ancillary services to the electrical grid and renewable energy can be utilized to power water-related infrastructure, but the potential for co-managed systems has not yet been quantified or fully characterized. Co-management and optimization of energy and water resources could lead to improved reliability and economic operating conditions. Energy-water microgrids could be a promising solution to improve energy and water resource management for islands, rural communities, distributed generation, Defense operations, and many parts of the world lacking critical infrastructure.The National Renewable Energy Laboratory (NREL) and the University of Arizona have been jointly researching energy-water microgrid opportunities through an effort at the university's BioSphere 2 (B2) Earth systems science research facility. B2 is an ideal case study for an energy-water microgrid test site, given its size, its unique mission and operations, the existence and criticality of water and energy infrastructure, and its ability to operate connected-to or disconnected-from the local electrical grid. Moreover, the B2 is a premier facility for undertaking agricultural research, providing an excellent opportunity to evaluate connections and tradeoffs in the food-energy-water nexus. The research effort at B2 identified the technical potential and associated benefits of an energy-water microgrid through the evaluation of energy ancillary services and peak load reductions and quantified the potential for B2 water-related loads to be utilized and modified to provide

  8. Cost Analysis of Renewable Energy-Based Microgrids

    Giraldez Miner, Julieta I [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Singh, Shruti [University of Denver; Gao, David Wenzhong [University of Denver

    2017-11-16

    This paper analyzes the cost composition of microgrid construction as well as the influencing key factors. The Microgrid Cost Study aims at identifying the average cost of a typical microgrid project. The project is limited to the vicinity of U.S. and hence takes into account of only existing microgrid projects in U.S. The project's objective is to find cost of microgrid and its individual components for next 5 years. This will help in R&D for future microgrid projects as well as help investors/developers/researchers get an idea about the cost of their projects that they might want to start in near future.

  9. Energy management and cooperation in microgrids

    Rahbar, Katayoun

    Microgrids are key components of future smart power grids, which integrate distributed renewable energy generators to efficiently serve the load demand locally. However, random and intermittent characteristics of renewable energy generations may hinder the reliable operation of microgrids. This thesis is thus devoted to investigating new strategies for microgrids to optimally manage their energy consumption, energy storage system (ESS) and cooperation in real time to achieve the reliable and cost-effective operation. This thesis starts with a single microgrid system. The optimal energy scheduling and ESS management policy is derived to minimize the energy cost of the microgrid resulting from drawing conventional energy from the main grid under both the off-line and online setups, where the renewable energy generation/load demand are assumed to be non-causally known and causally known at the microgrid, respectively. The proposed online algorithm is designed based on the optimal off-line solution and works under arbitrary (even unknown) realizations of future renewable energy generation/load demand. Therefore, it is more practically applicable as compared to solutions based on conventional techniques such as dynamic programming and stochastic programming that require the prior knowledge of renewable energy generation and load demand realizations/distributions. Next, for a group of microgrids that cooperate in energy management, we study efficient methods for sharing energy among them for both fully and partially cooperative scenarios, where microgrids are of common interests and self-interested, respectively. For the fully cooperative energy management, the off-line optimization problem is first formulated and optimally solved, where a distributed algorithm is proposed to minimize the total (sum) energy cost of microgrids. Inspired by the results obtained from the off-line optimization, efficient online algorithms are proposed for the real-time energy management

  10. A Micro-Grid Battery Storage Management

    Mahat, Pukar; Escribano Jiménez, Jorge; Moldes, Eloy Rodríguez

    2013-01-01

    An increase in number of distributed generation (DG) units in power system allows the possibility of setting-up and operating micro-grids. In addition to a number of technical advantages, micro-grid operation can also reduce running costs by optimally scheduling the generation and/or storage...... systems under its administration. This paper presents an optimized scheduling of a micro-grid battery storage system that takes into account the next-day forecasted load and generation profiles and spot electricity prices. Simulation results show that the battery system can be scheduled close to optimal...

  11. Current Capabilities at SNL for the Integration of Small Modular Reactors onto Smart Microgrids Using Sandia's Smart Microgrid Technology High Performance Computing and Advanced Manufacturing.

    Rodriguez, Salvador B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    Smart grids are a crucial component for enabling the nation’s future energy needs, as part of a modernization effort led by the Department of Energy. Smart grids and smart microgrids are being considered in niche applications, and as part of a comprehensive energy strategy to help manage the nation’s growing energy demands, for critical infrastructures, military installations, small rural communities, and large populations with limited water supplies. As part of a far-reaching strategic initiative, Sandia National Laboratories (SNL) presents herein a unique, three-pronged approach to integrate small modular reactors (SMRs) into microgrids, with the goal of providing economically-competitive, reliable, and secure energy to meet the nation’s needs. SNL’s triad methodology involves an innovative blend of smart microgrid technology, high performance computing (HPC), and advanced manufacturing (AM). In this report, Sandia’s current capabilities in those areas are summarized, as well as paths forward that will enable DOE to achieve its energy goals. In the area of smart grid/microgrid technology, Sandia’s current computational capabilities can model the entire grid, including temporal aspects and cyber security issues. Our tools include system development, integration, testing and evaluation, monitoring, and sustainment.

  12. Northern micro-grid project

    Curtis, David; Singh, Bob

    2010-09-15

    The electrical distribution system for the Kasabonika Lake First Nation in northern Ontario (Canada) consumed 1.2 million liters of diesel fuel in 2008, amounting to 3,434 tones of CO2 emissions. The Northern Micro-Grid Project, supported by seven partners, involves integrating renewable generation & storage into the Kasabonika Lake distribution system. Through R&D and demonstration, the objectives are to reduce the amount of diesel consumed, support the distribution system exclusively on renewable resources during light loads, engage and impart knowledge/training to better position the community for future opportunities. The paper will discuss challenges, opportunities and future plans associated with the project.

  13. On battery-less autonomous polygeneration microgrids: Investigation of the combined hybrid capacitors/hydrogen alternative

    Kyriakarakos, George; Piromalis, Dimitrios D.; Arvanitis, Konstantinos G.; Dounis, Anastasios I.; Papadakis, George

    2015-01-01

    Highlights: • A battery-less autonomous polygeneration microgrid is technically feasible. • Laboratory testing of hybrid capacitors. • Investigation of hybrid capacitors utilization along with hydrogen subsystem. - Abstract: The autonomous polygeneration microgrid topology aims to cover holistically the needs in remote areas as far as electrical power, potable water through desalination, fuel for transportation in the form of hydrogen, heating and cooling are concerned. Deep discharge lead acid batteries are mostly used in such systems, associated with specific disadvantages, both technical and environmental. This paper investigated the possibility of replacing the battery bank from a polygeneration microgrid with a hybrid capacitor bank and more intensive utilization of a hydrogen subsystem. Initially commercial hybrid capacitors were tested under laboratory conditions and based on the respective results a case study was performed. The optimized combination of hybrid capacitors and higher hydrogen usage was then investigated through simulations and compared to a polygeneration microgrid featuring deep discharge lead acid batteries. From the results it was clear that it is technically possible to exchange the battery bank with a hybrid capacitor bank and higher hydrogen utilization. From the economic point of view, the current cost of the hybrid capacitors and the hydrogen components is high which leads to higher overall cost in comparison with deep discharge lead acid batteries. Taking into account, though, the decreasing cost prospects and trends of both the hybrid capacitors and the hydrogen components it is expected that this approach will become economically competitive in a few years

  14. Intelligent energy management control for independent microgrid

    Energy management control; multi-agent system; microgrid; energy forecast; hybrid power ... power to the local load most of the time in this energy management strategy. ... Electrical and Electronics Engineering Department, PSG College of ...

  15. Computational optimization techniques applied to microgrids planning

    Gamarra, Carlos; Guerrero, Josep M.

    2015-01-01

    Microgrids are expected to become part of the next electric power system evolution, not only in rural and remote areas but also in urban communities. Since microgrids are expected to coexist with traditional power grids (such as district heating does with traditional heating systems......), their planning process must be addressed to economic feasibility, as a long-term stability guarantee. Planning a microgrid is a complex process due to existing alternatives, goals, constraints and uncertainties. Usually planning goals conflict each other and, as a consequence, different optimization problems...... appear along the planning process. In this context, technical literature about optimization techniques applied to microgrid planning have been reviewed and the guidelines for innovative planning methodologies focused on economic feasibility can be defined. Finally, some trending techniques and new...

  16. Modular Power Architectures for Microgrid Clusters

    Lin, Hengwei; Liu, Leo; Guerrero, Josep M.

    2014-01-01

    One of the most important elements in microgrids is the configuration architecture which includes installed capacity, devices location, converter topologies, as well as system control and management strategies. Reliability, security and stability in microgrids require global communication systems...... in order to provide information for management, supervision, and protection purposes. In this paper, the main objective is to reveal the reasons leading to unreliability and insecurity in microgrids systems, and to propose a generic modular concept which is conceived from the viewpoint of a unified system....... The user-frame concept proposed here when designing microgrids considers that the end-user is the basis for the geographical deployment. Meanwhile, a modular user-oriented approach is adopted in order to enhance reliability and expansibility. Finally, a unified dispatching and hierarchical management...

  17. A Review of Power Electronics Based Microgrids

    Wang, Xiongfei; Guerrero, Josep M.; Blaabjerg, Frede

    2012-01-01

    The increased penetration of Distributed Energy Resources (DER) is challenging the entire architecture of conventional electrical power system. Microgrid paradigm, featuring higher flexibility and reliability, becomes an attractive candidate for the future power grid. In this paper, an overview o...

  18. A microgrid cluster structure and its autonomous coordination control strategy

    Zhou, Xiaoping; Zhou, Leming; Chen, Yandong

    2018-01-01

    This paper proposes a microgrid cluster structure and its autonomous coordination control strategy. Unlike existing microgrids that are purely AC or DC, the microgrid cluster studied here is an interconnected system with multiple AC and DC microgrids, which enables mutual power support among...... control method combining the normalized droop-based control and adaptive control is proposed for PEU, which can effectively realize mutual power support among microgrids and reduce the bus voltage or frequency deviation in microgrids. In addition, the adaptive control strategy of PEU can ensure...... that the bigger the normalized index of microgrid is, the larger the active power exchange coefficient is, which can make all of microgrids operate around the rated state as much as possible. Besides, EP is mainly used to balance the system power, and the hierarchical coordinated control method of EP is proposed...

  19. Cooperative Frequency Control for Autonomous AC Microgrids

    Shafiee, Qobad; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2015-01-01

    Distributed secondary control strategies have been recently studied for frequency regulation in droop-based AC Microgrids. Unlike centralized secondary control, the distributed one might fail to provide frequency synchronization and proportional active power sharing simultaneously, due to having...... not require measuring the system frequency as compared to the other presented methods. An ac Microgrid with four sources is used to verify the performance of the proposed control methodology....

  20. Microgrids and distributed generation systems: Control, operation, coordination and planning

    Che, Liang

    Distributed Energy Resources (DERs) which include distributed generations (DGs), distributed energy storage systems, and adjustable loads are key components in microgrid operations. A microgrid is a small electric power system integrated with on-site DERs to serve all or some portion of the local load and connected to the utility grid through the point of common coupling (PCC). Microgrids can operate in both grid-connected mode and island mode. The structure and components of hierarchical control for a microgrid at Illinois Institute of Technology (IIT) are discussed and analyzed. Case studies would address the reliable and economic operation of IIT microgrid. The simulation results of IIT microgrid operation demonstrate that the hierarchical control and the coordination strategy of distributed energy resources (DERs) is an effective way of optimizing the economic operation and the reliability of microgrids. The benefits and challenges of DC microgrids are addressed with a DC model for the IIT microgrid. We presented the hierarchical control strategy including the primary, secondary, and tertiary controls for economic operation and the resilience of a DC microgrid. The simulation results verify that the proposed coordinated strategy is an effective way of ensuring the resilient response of DC microgrids to emergencies and optimizing their economic operation at steady state. The concept and prototype of a community microgrid that interconnecting multiple microgrids in a community are proposed. Two works are conducted. For the coordination, novel three-level hierarchical coordination strategy to coordinate the optimal power exchanges among neighboring microgrids is proposed. For the planning, a multi-microgrid interconnection planning framework using probabilistic minimal cut-set (MCS) based iterative methodology is proposed for enhancing the economic, resilience, and reliability signals in multi-microgrid operations. The implementation of high-reliability microgrids

  1. INCIDENCIA DE LOS MECANISMOS DE CERTIFICACIÓN FINANCIERA (CAT-CERT SOBRE LAS EXPORTACIONES NO TRADICIONALES COLOMBIANAS

    MIGUEL DAVID ROJAS LÓPEZ

    2009-01-01

    Full Text Available Esta investigación muestra la incidencia de los CERT´s en las exportaciones no tradicionales colombianas. Inicialmente se analiza gráficamente la evolución de exportaciones no tradicionales y la evolución del nivel de CERT. Luego mediante una regresión lineal simple se determina la influencia del CERT durante el período 1970-2000 sobre las exportaciones menores. Las conclusiones sobre los aspectos principales son explicadas al final del artículo.

  2. Feasibility of microgrids for business sites in the Netherlands

    Wattjes, F.; Kramp, A.

    2015-01-01

    This paper analyses the feasibility of smart microgrids for business sites by means of a new developed Business Analysis Model. Smart microgrids accommodate the local power exchange between local production and consumption via smart grid technologies. Without regulatory changes smart microgrids are

  3. A Review of Microgrid Architectures and Control Strategy

    Jadav, Krishnarajsinh A.; Karkar, Hitesh M.; Trivedi, I. N.

    2017-12-01

    In this paper microgrid architecture and various converters control strategies are reviewed. Microgrid is defined as interconnected network of distributed energy resources, loads and energy storage systems. This emerging concept realizes the potential of distributed generators. AC microgrid interconnects various AC distributed generators like wind turbine and DC distributed generators like PV, fuel cell using inverter. While in DC microgrid output of an AC distributed generator must be converted to DC using rectifiers and DC distributed generator can be directly interconnected. Hybrid microgrid is the solution to avoid this multiple reverse conversions AC-DC-AC and DC-AC-DC that occur in the individual AC-DC microgrid. In hybrid microgrid all AC distributed generators will be connected in AC microgrid and DC distributed generators will be connected in DC microgrid. Interlinking converter is used for power balance in both microgrids, which transfer power from one microgrid to other if any microgrid is overloaded. At the end, review of interlinking converter control strategies is presented.

  4. Microgrid Enabled Distributed Energy Solutions (MEDES) Fort Bliss Military Reservation

    2014-02-01

    FINAL REPORT Microgrid Enabled Distributed Energy Solutions (MEDES) Fort Bliss Military Reservation ESTCP Project EW-201140 FEBRUARY...TITLE AND SUBTITLE Microgrid Enabled Distributed Energy Solutions (MEDES) 5a. CONTRACT NUMBER W912HQ-11-C-0082 Fort Bliss, Texas...Lockheed Martin’s Intelligent Microgrid Solution can provide more energy security while also lowering electric utility costs and greenhouse gas emissions

  5. Operational aspects of a microgrid with battery storage

    Overbeeke, van F.; Cobben, J.F.G.

    2010-01-01

    Microgrids are receiving increasing attention as a result of the growing attractiveness of small-scale electricity generation. The authors have developed a pilot test site in the framework of the European project MORE MICROGRIDS, aiming at proving the technical feasibility of the microgrid control

  6. Tests at constant extension velocity CERT for the evaluation of environmental assisted cracking

    Arganis J, C.R.

    1994-01-01

    The test at constant velocity extension (CERT) is firmly established as a technique for the study of environmentally cracking (stress corrosion and hydrogen embrittlement) and is widely used, mainly in mechanistic studies. In CERT test, an increasing charge is applied to a sample and the extension velocity is hold up constant to allow that corrosion interplay in the process. The type of crack and ductility measurements with the conditions for testing are compared with a cracked sample in an inert media. Required equipment: 1) A charge mechanism capable to control the elongation of test samples in a rank of 1 x 10 -5 to 1 x 10 -7 inch/inch sec and capable to hold up constant such elongation. 2) A suitable standard (Astm standard A-370). 3) A chamber or cell for the media in which the chemical composition of the solution, the gas composition, the pressure, temperature and electrochemical potential can be controlled in order to simulate with anticipation the service conditions. The cell must allow the mechanical access of the test sample to the charge train of the machine. (Author)

  7. Energy management of an experimental microgrid coupled to a V2G system

    Mendes, Paulo R. C.; Isorna, Luis Valverde; Bordons, Carlos; Normey-Rico, Julio E.

    2016-09-01

    This paper presents an algorithm for economic optimization of a laboratory microgrid. The microgrid incorporates a hybrid storage system composed of a battery bank and a hydrogen storage and it has a connection with the external electrical network and a charging station for electric vehicles. To study the impact of use of renewable energy power systems, the microgrid has a programmable power supply that can emulate the dynamic behavior of a wind turbine and/or a photovoltaic field. The system modeling was carried out using the Energy Hubs methodology. A hierarchical control structure is proposed based on Model Predictive Control and acting in different time scales, where the first level is responsible for maintaining the microgrid stability and the second level has the task of performing the management of electricity purchase and sale to the power grid, maximize the use of renewable energy sources, manage the use of energy storages and perform the charge of the parked vehicles. Practical experiments were performed with different weather conditions of solar irradiation and wind. The results show a reliable operation of the proposed control system.

  8. Microgrids: Reliable power in a small package

    Krotz, D.

    2003-01-01

    A new approach to power generation in which a cluster of small, on-site generators serve office buildings, industrial parks and homes, is being developed by scientists at the University of California's Berkeley Campus. Called microgrid, the system may well be the answer to satisfying the growing thirst for electricity without the danger of overburdening the aging transmission lines, or building 1,000 new power plants that would be required to meet the ever-growing demand. The new approach relies on small generators such as ordinary reciprocating engines, microturbines, fuel cells, and photovoltaic systems. This microgrid of small generators appears to the main grid as just an ordinary customer. When the grid offers cheap electricity, the microgrid can purchase it, but when prices rise, or when there is a power failure, the microgrid can isolate itself, ensuring uninterrupted power to critical equipment such as computers, communications infrastructure and control systems. The idea is that if sensitive equipment can be powered locally, the vulnerable centralized power system becomes much less critical. The microgrid could be powered by recovered waste heat, a currently wasted by-product of power generation. Waste heat could also cool and dehumidify buildings using thermally activated processes. Microgrids also have the potential to introduce real competition into the electricity market by offering customers a choice; this is expected to have the effect of imposing competitive discipline on power companies. To extend the potential even farther, it is considered well within the realm of possibility that by introducing fuel cell-powered cars into the microgrid, the car could be used as a source of power by simply parking it and plugging it in to supply electricity to the home or the office

  9. Microgrids Technologies in Future Seaports

    Baizura Binti Ahamad, Nor; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2018-01-01

    issues, shore-side-power emerges as an initial solution to mitigate the unwanted environmental impact of ships at berth. In addition to this, port development must be in line with the emerging ships technologies as most of the ships are moving forward All-Electric-Ship (AES) concept. However, the use......The issue is mostly attributable to the growth of maritime, inland shipping, waterborne transport and trade demand in the freight sector. This fundamental problem is being a key concern for the European Commission because it leads to adverse health and environmental effects. To solve the emission...... of shore-side-power is still new, although the international standard was recently available, shore-side-power still facing technical challenges like power supply/demand power, different voltage, and frequency level on the ship and port side. Therefore, the integration of microgrid technologies...

  10. Village microgrids: The Chile project

    Baring-Gould, E.I.

    1997-12-01

    This paper describes a village application in Chile. The objective was to demonstrate the technical, economic and institutional viability of renewable energy for rural electrification, as well as to allow local partners to gain experience with hybrid/renewable technology, resource assessment, system siting and operation. A micro-grid system is viewed as a small village system, up to 1200 kWh/day load with a 50 kW peak load. It can consist of components of wind, photovoltaic, batteries, and conventional generators. It is usually associated with a single generator source, and uses batteries to cover light day time loads. This paper looks at the experiences learned from this project with regard to all of the facets of planning and installing this project.

  11. The American Board of Emergency Medicine ConCert Examination: Emergency Physicians' Perceptions of Learning and Career Benefits.

    Marco, Catherine A; Wahl, Robert P; Counselman, Francis L; Heller, Barry N; Harvey, Anne L; Joldersma, Kevin B; Kowalenko, Terry; Coombs, Andrea B; Reisdorff, Earl J

    2016-09-01

    As part of the American Board of Emergency Medicine (ABEM) Maintenance of Certification (MOC) program, ABEM-certified physicians are required to pass the Continuous Certification (ConCert) examination at least every 10 years. With the 2015 ConCert examination, ABEM sought to better understand emergency physicians' perceptions of the benefits of preparing for and taking the examination and the career benefits of staying ABEM-certified. This was a prospective survey study. A voluntary postexamination survey was administered at the end of the 2015 ABEM ConCert examination (September 21-26, 2015). Physicians were asked about the benefits of preparing for the examination and maintaining ABEM certification. Examination performance was compared to perceptions of learning and career benefits. Of the 2,601 on-time test takers, 2,511 respondents participated (96.5% participation rate). The majority of participants (92.0%) identified a benefit to preparing for the ConCert examination, which included reinforced medical knowledge (73.9%), increased knowledge (66.8%), and making them a better clinician (39.4%). The majority of respondents (90.8%) identified a career benefit of maintaining ABEM certification, which included more employment options (73.8%), more positively viewed by other physicians (56.8%), and better financial outcomes (29.8%). There was a statistically significant association between the perception of knowledge reinforcement and examination performance (p Medicine.

  12. InTraCert. Inception report. The role of an integrated tradable green certificate system in a liberalising market

    Boots, M.G.; Schaeffer, G.J.; De Zoeten, C.; Mitchell, C.; Anderson, T.; Morthorst, P.E.; Nielsen, L.; Gual, M.; Del Rio, P.; Cadenas, A.; Hernandez, F.; Kuehn, I.; Braeur, W.; Stronzik, M.

    2000-12-01

    The InTraCert project aims to explore the possibility of integrating the existing and planned Tradable Green Certificate (TGC) schemes in the European Union and, therefore, creating a plausible unified market for TGCs. Particular attention will be paid to the possibilities of integrating TGCs for green electricity, heat and gas. Furthermore, it intents to examine the possible interactions arising from such a system with more direct GHG abatement measures, i.e. Carbon Emissions Trading (CET). The scope of the InTraCert project requires specific information for EU-15 countries regarding, on the one hand, Renewable Energy Sources (RES) used for electricity, gas and heat generation and. on the other, GHG emission levels and national strategies. In order to account for this information need. specific country inventories have been designed and carried out by InTraCert members in this first phase of the project. The inventory shows that Belgium, Italy, Denmark, the Netherlands, Austria, Sweden and the UK seriously want to implement a TGC system. The systems will indeed be nationally oriented; hardly any provisions for international trade in the different TGCs will be put in place. An essential prerequisite for efficient cross border trade is agreement on the carbon credit that comes with RE production. What is the size of the carbon credit and will this credit be attached to the TGC while traded? These will be the main questions to be answered in the next phase of the InTraCert project. 8 refs

  13. Data-driven modeling of solar-powered urban microgrids.

    Halu, Arda; Scala, Antonio; Khiyami, Abdulaziz; González, Marta C

    2016-01-01

    Distributed generation takes center stage in today's rapidly changing energy landscape. Particularly, locally matching demand and generation in the form of microgrids is becoming a promising alternative to the central distribution paradigm. Infrastructure networks have long been a major focus of complex networks research with their spatial considerations. We present a systemic study of solar-powered microgrids in the urban context, obeying real hourly consumption patterns and spatial constraints of the city. We propose a microgrid model and study its citywide implementation, identifying the self-sufficiency and temporal properties of microgrids. Using a simple optimization scheme, we find microgrid configurations that result in increased resilience under cost constraints. We characterize load-related failures solving power flows in the networks, and we show the robustness behavior of urban microgrids with respect to optimization using percolation methods. Our findings hint at the existence of an optimal balance between cost and robustness in urban microgrids.

  14. A New Seamless Transfer Control Strategy of the Microgrid

    Zhaoyun Zhang

    2014-01-01

    Full Text Available A microgrid may operate under two typical modes; the seamless transfer control of the microgrid is very important. The mode conversion controller is installed in microgrid and the control logic of master power is optimized for microgrid mode conversion. In the proposed scheme, master power is very important. The master-power is under the PQ control when microgrid is under grid-connected. And it is under V/F control when the microgrid is under islanding. The microgrid mode controller is used to solve the planned conversion. Three types of conversion are simulated in this paper. The simulation results show the correctness and validity of the mode control scheme. Finally, the implementation and application of the operation and control device are described.

  15. A new seamless transfer control strategy of the microgrid.

    Zhang, Zhaoyun; Chen, Wei; Zhang, Zhe

    2014-01-01

    A microgrid may operate under two typical modes; the seamless transfer control of the microgrid is very important. The mode conversion controller is installed in microgrid and the control logic of master power is optimized for microgrid mode conversion. In the proposed scheme, master power is very important. The master-power is under the PQ control when microgrid is under grid-connected. And it is under V/F control when the microgrid is under islanding. The microgrid mode controller is used to solve the planned conversion. Three types of conversion are simulated in this paper. The simulation results show the correctness and validity of the mode control scheme. Finally, the implementation and application of the operation and control device are described.

  16. Distributed cooperative control of AC microgrids

    Bidram, Ali

    In this dissertation, the comprehensive secondary control of electric power microgrids is of concern. Microgrid technical challenges are mainly realized through the hierarchical control structure, including primary, secondary, and tertiary control levels. Primary control level is locally implemented at each distributed generator (DG), while the secondary and tertiary control levels are conventionally implemented through a centralized control structure. The centralized structure requires a central controller which increases the reliability concerns by posing the single point of failure. In this dissertation, the distributed control structure using the distributed cooperative control of multi-agent systems is exploited to increase the secondary control reliability. The secondary control objectives are microgrid voltage and frequency, and distributed generators (DGs) active and reactive powers. Fully distributed control protocols are implemented through distributed communication networks. In the distributed control structure, each DG only requires its own information and the information of its neighbors on the communication network. The distributed structure obviates the requirements for a central controller and complex communication network which, in turn, improves the system reliability. Since the DG dynamics are nonlinear and non-identical, input-output feedback linearization is used to transform the nonlinear dynamics of DGs to linear dynamics. Proposed control frameworks cover the control of microgrids containing inverter-based DGs. Typical microgrid test systems are used to verify the effectiveness of the proposed control protocols.

  17. Implementation of the Bronsbergen microgrid using FACDS

    Lava, J.; Kling, W.L. [Eindhoven Univ. of Technology (Netherlands). Dept. of Electrical Engineering; Cobben, J.F.G. [Eindhoven Univ. of Technology (Netherlands). Dept. of Electrical Engineering; Alliander N.V., Duiven (Netherlands); Overbeeke, F. van [EMforce B.V., Krimpen aan den IJssel (Netherlands)

    2010-07-01

    The integration of distributed generation (DG) in the electric network presents a challenging task for grid operators. While DGs can be considered beneficial for the environment since they are powered by renewable energy sources, unwanted effects on power quality, equipment and personnel safety, and power system protection can be seen when these generators are in service. A solution to these problems is to group distributed generation and the loads into small network clusters called microgrids. A microgrid is a group of energy sources and loads operating semi-independently of the external grid (or the macro grid). The micro grids are seen by the power system as a single, controlled unit that is behaving either as a load or source. For the customer and the utility, the microgrid can be tailor-made to perform a numer of tasks such as enhancing reliability, optimizing the use of renewable energy, improving voltage quality, etc. This paper presents the implementation, field test and simulation results of a pilot microgrid in the Netherlands. The objective is to implement a self-supporting, reliable and efficient microgrid operation. (orig.)

  18. Performance evaluation of accelerated protection for microgrids

    Wei, P.; Lin, X. [Huazhong Univ. of Science and Technology (China); Klimek, A. [Powertech Labs Inc., Surrey, BC (Canada); Bo, Z. [Alstom Grid Automation (United Kingdom)

    2010-07-01

    The constraints of existing power system facilities are becoming apparent as the demand for electricity increases. This paper discussed the use of microgrids as a means of improving power quality, safety, and stability. There are currently 2 main methods for protecting microgrids, notably voltage measurement, and a differential current method. The methods both assume that the microgrid is divided into zones determined by the location of distributed generators (DGs) in the power system. When faults are detected by protection relays, the DG in the microgrid zone will be shut off. Conventional protection coordination methods result in long fault clearance times. Relay coordination calculation methods are complicated when microgrids include a number of DGs that may be vulnerable to fault disturbances. This paper described a non-communication protection technique designed to detect faults zones using a superimposed phase current of the sound phase following breaker trips at the other end of the faulted line section. The method was designed to accelerate the tripping speed of the breaker at the local end of the faulted line. The technique can also be used to protect distribution systems with double source or radial configurations. 5 refs., 2 tabs., 14 figs.

  19. Protection of AC and DC Microgrids

    Beheshtaein, Siavash; Savaghebi, Mehdi; Quintero, Juan Carlos Vasquez

    2015-01-01

    and DC microgrids, and then investigates the existing and promising solutions for the corresponding challenges. To the authors’ knowledge, three parts of smart grids are required to be developed to facilitate implementation of protection scheme in microgrids. The main requirements and open issues......In future, distributed energy resources (RESs) will be utilized at consumption points. As a consequence, power flow and fault current would be bidirectional and topologydependent; and hence the conventional protection strategies would be inefficient. This paper categorizes the main challenges in AC...

  20. Autonomous control of distributed storages in microgrids

    Loh, Poh Chiang; Blaabjerg, Frede

    2011-01-01

    Operation of distributed generators in microgrids has widely been discussed, but would not be fully autonomous, if distributed storages are not considered. Storages in general are important, since they provide energy buffering to load changes, energy leveling to source variations and ride......-through enhancement to the overall microgrids. Recognizing their importance, this paper presents a scheme for sharing power among multiple distributed storages, in coordination with the distributed sources and loads. The scheme prompts the storages to autonomously sense for system conditions, requesting for maximum...

  1. Line-Interactive UPS for Microgrids

    Abusara, Mohammad; Guerrero, Josep M.; Sharkh, Suleiman

    2014-01-01

    Line interactive Uninterruptable Power Supply (UPS) systems are good candidates for providing energy storage within a microgrid to help improve its reliability, economy and efficiency. In grid-connected mode, power can be imported from the grid by the UPS to charge its battery. Power can also...... drooping technique to ensure seamless transfer between grid-connected and stand-alone parallel modes of operation. The drooping coefficients are chosen to limit the energy imported by the USP when re-connecting to the grid and to give good transient response. Experimental results of a microgrid consisting...

  2. Control of Power Converters in AC Microgrids

    Rocabert, Joan; Luna, Alvaro; Blaabjerg, Frede

    2012-01-01

    The enabling of ac microgrids in distribution networks allows delivering distributed power and providing grid support services during regular operation of the grid, as well as powering isolated islands in case of faults and contingencies, thus increasing the performance and reliability of the ele......The enabling of ac microgrids in distribution networks allows delivering distributed power and providing grid support services during regular operation of the grid, as well as powering isolated islands in case of faults and contingencies, thus increasing the performance and reliability...

  3. Power flow control of intertied ac microgrids

    Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Microgrids are small reliable grids formed by clustering distributed sources and loads together. They can, in principle, operate at different voltages and frequencies like 50, 60, 400 Hz or even dc. Tying them together or to the mains grid for energy sharing would therefore require the insertion...... of interlinking power converters. Active and reactive power flows of these converters should preferably be managed autonomously without demanding for fast communication links. A scheme that can fulfill the objectives is now proposed, which upon realised, will result in more robustly integrated microgrids...

  4. Hierarchical MAS based control strategy for microgrid

    Xiao, Z.; Li, T.; Huang, M.; Shi, J.; Yang, J.; Yu, J. [School of Information Science and Engineering, Yunnan University, Kunming 650091 (China); Xiao, Z. [School of Electrical and Electronic Engineering, Nanyang Technological University, Western Catchment Area, 639798 (Singapore); Wu, W. [Communication Branch of Yunnan Power Grid Corporation, Kunming, Yunnan 650217 (China)

    2010-09-15

    Microgrids have become a hot topic driven by the dual pressures of environmental protection concerns and the energy crisis. In this paper, a challenge for the distributed control of a modern electric grid incorporating clusters of residential microgrids is elaborated and a hierarchical multi-agent system (MAS) is proposed as a solution. The issues of how to realize the hierarchical MAS and how to improve coordination and control strategies are discussed. Based on MATLAB and ZEUS platforms, bilateral switching between grid-connected mode and island mode is performed under control of the proposed MAS to enhance and support its effectiveness. (authors)

  5. Regulation of microgeneration and microgrids

    Moises Costa, Paulo; Matos, Manuel A.; Pecas Lopes, J.A.

    2008-01-01

    The concept of microgrid (μGrid) has been emerging as a way to integrate microgeneration (μG) in low-voltage (LV) networks and simultaneously improve its potential benefits. Technical requirements to connect μgrids to LV networks have been studied in order to make this concept technologically feasible and safe to operate. However, the regulatory framework for economic integration of μG and μGrids on distribution systems, despite being crucial, is still an open issue. The main purpose of this paper is to contribute for the development of an appropriate economic regulation framework that removes the barriers to μG and μGrid development. To do so, the relevant costs and benefits resulting from the establishment of μG and μGrid are identified and a methodology for sharing those costs and benefits among the involved economic agents is presented. The only pre-requisite of such a methodology is the existence of a net benefit to all economic agents

  6. Regulation of microgeneration and microgrids

    Moises Costa, Paulo [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal)], E-mail: paulomoises@elect.estv.ipv.pt; Matos, Manuel A.; Pecas Lopes, J.A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2008-10-15

    The concept of microgrid ({mu}Grid) has been emerging as a way to integrate microgeneration ({mu}G) in low-voltage (LV) networks and simultaneously improve its potential benefits. Technical requirements to connect {mu}grids to LV networks have been studied in order to make this concept technologically feasible and safe to operate. However, the regulatory framework for economic integration of {mu}G and {mu}Grids on distribution systems, despite being crucial, is still an open issue. The main purpose of this paper is to contribute for the development of an appropriate economic regulation framework that removes the barriers to {mu}G and {mu}Grid development. To do so, the relevant costs and benefits resulting from the establishment of {mu}G and {mu}Grid are identified and a methodology for sharing those costs and benefits among the involved economic agents is presented. The only pre-requisite of such a methodology is the existence of a net benefit to all economic agents.

  7. Regulation of microgeneration and microgrids

    Costa, Paulo Moises [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal); Matos, Manuel A.; Pecas Lopes, J.A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2008-10-15

    The concept of microgrid ({mu}Grid) has been emerging as a way to integrate microgeneration ({mu}G) in low-voltage (LV) networks and simultaneously improve its potential benefits. Technical requirements to connect {mu}grids to LV networks have been studied in order to make this concept technologically feasible and safe to operate. However, the regulatory framework for economic integration of {mu}G and {mu}Grids on distribution systems, despite being crucial, is still an open issue. The main purpose of this paper is to contribute for the development of an appropriate economic regulation framework that removes the barriers to {mu}G and {mu}Grid development. To do so, the relevant costs and benefits resulting from the establishment of {mu}G and {mu}Grid are identified and a methodology for sharing those costs and benefits among the involved economic agents is presented. The only pre-requisite of such a methodology is the existence of a net benefit to all economic agents. (author)

  8. Tariff Considerations for Micro-Grids in Sub-Saharan Africa

    Reber, Timothy J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Booth, Samuel S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cutler, Dylan S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Li, Xiangkun [National Renewable Energy Lab. (NREL), Golden, CO (United States); Salasovich, James A. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2018-02-16

    This report examines some of the key drivers and considerations policymakers and decision makers face when deciding if and how to regulate electricity tariffs for micro-grids. Presenting a range of tariff options, from mandating some variety of national (uniform) tariff to allowing micro-grid developers and operators to set fully cost-reflective tariffs, it examines various benefits and drawbacks of each. In addition, the report and explores various types of cross-subsidies and other transitional forms of regulation that may offer a regulatory middle ground that can help balance the often competing goals of providing price control on electricity service in the name of social good while still providing a means for investors to ensure high enough returns on their investment to attract the necessary capital financing to the market. Using the REopt tool developed by the U.S. Department of Energy's National Renewable Energy Laboratory to inform their study, the authors modeled a few representative micro-grid systems and the resultant levelized cost of electricity, lending context and scale to the consideration of these tariff questions. This simple analysis provides an estimate of the gap between current tariff regimes and the tariffs that would be necessary for developers to recover costs and attract investment, offering further insight into the potential scale of subsidies or other grants that may be required to enable micro-grid development under current regulatory structures. It explores potential options for addressing this gap while trying to balance This report examines some of the key drivers and considerations policymakers and decision makers face when deciding if and how to regulate electricity tariffs for micro-grids. Presenting a range of tariff options, from mandating some variety of national (uniform) tariff to allowing micro-grid developers and operators to set fully cost-reflective tariffs, it examines various benefits and drawbacks of each. In

  9. Autonomous power management for interlinked AC-DC microgrids

    Nutkani, Inam Ullah; Meegahapola, Lasantha; Andrew, Loh Poh Chiang

    2018-01-01

    of the DC micro-grid before importing power from the interlinked AC microgrid. This strategy enables voltage regulation in the DC microgrid, and also reduces the number of converters in operation. The proposed scheme is fully autonomous while it retains the plug-n-play features for generators and tie......The existing power management schemes for inter-linked AC-DC microgrids have several operational drawbacks. Some of the existing control schemes are designed with the main objective of sharing power among the interlinked microgrids based on their loading conditions, while other schemes regulate...... the voltage of the interlinked microgrids without considering the specific loading conditions. However, the existing schemes cannot achieve both objectives efficiently. To address these issues, an autonomous power management scheme is proposed, which explicitly considers the specific loading condition...

  10. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.

    2015-01-01

    This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics....... The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing DG’s output power. When the microgrid is operating...... and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances...

  11. Advanced Microgrid Concepts and Technologies Workshop

    2013-04-01

    Prognostics for Microgrid Components—Abhinav Saxena, NASA Ames Research Center...but very expensive; companies: Trek , Omron, SMC, Plessey Semiconductors, Quasar Federal Systems) o Field meters (chopper or rotating vane technology...still relatively expensive and low precision; companies: Monroe, Trek , AlphaLab, Campbell Scientific) • Why do we need anything beyond what is

  12. Hierarchical Control for Multiple DC Microgrids Clusters

    Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2014-01-01

    This paper presents a distributed hierarchical control framework to ensure reliable operation of dc Microgrid (MG) clusters. In this hierarchy, primary control is used to regulate the common bus voltage inside each MG locally. An adaptive droop method is proposed for this level which determines...

  13. Voltage control of DC islanded microgrids

    Tucci, Michele; Riverso, Stefano; Quintero, Juan Carlos Vasquez

    2015-01-01

    We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC...

  14. Secure Automated Microgrid Energy System (SAMES)

    2016-12-01

    electrical components of the clustered microgrid, using sophisticated analysis to provide a real time comparison of predicted operation to actual...in spring and fall months when electricity consumption is not affected by summer air-conditioning or winter heating loads. There are a variety of...30 Figure 14. Energy Consumption at Buildings 1-7, Naval Medical Center

  15. Microgrids : Experiences, barriers and success factors

    Soshinskaya, Mariya; Crijns - Graus, Wina|info:eu-repo/dai/nl/308005015; Guerrero, Josep M.; Vasquez, Juan C.

    2014-01-01

    Although microgrids have been researched for over a decade and recognized for their multitude of benefits to improve power reliability, security, sustainability, and decrease power costs for the consumer, they have still not reached rapid commercial growth. The main aim of this research is to

  16. Secondary control for microgrids using potential functions

    Mehrizi-Sani, A.; Iravani, R. [Toronto Univ., ON (Canada)

    2009-07-01

    Issues with power grids include reliability, aging infrastructure, limited use of communications, efficiency, and low asset utilization. The smart grid involves a vision of the future electric system. Core elements of the smart grid include information technology, communication, and power electronic devices. This presentation discussed and compared the current grid with the smart grid and presented operational requirements of the microgrid. The concept of potential functions for secondary control based on availability of communication within the microgrid was introduced. The smart grid vision requires the microgrid to remain in operation even when islanded. The existing primary control does not guarantee stable islanded operation. Other topics that were discussed included primary and secondary control; proposed secondary control; the control hierarchy; and advantages and differences over conventional methods. A case study involving different scenarios was presented. It was concluded that the microgrid central controller minimizes each potential function to determine the set points of the corresponding distributed energy resources unit associated with the minimum of the potential function. tabs., figs.

  17. Bregman storage functions for microgrid control

    De Persis, Claudio; Monshizadeh, Nima

    In this paper, we contribute a theoretical framework that sheds a new light on the problem of microgrid analysis and control. The starting point is an energy function comprising the “kinetic” energy associated with the elements that emulate the rotating machinery and terms taking into account the

  18. Implementing Cyber Security Requirements and Mechanisms in Microgrids

    Mohan , Apurva; Khurana , Himanshu

    2015-01-01

    Part 4: INFRASTRUCTURE SECURITY; International audience; A microgrid is a collection of distributed energy resources, storage and loads under common coordination and control that provides a single functional interface to enable its management as a single unit. Microgrids provide several advantages such as power quality control, uninterrupted power supply and integration of renewable resources. However, microgrids are increasingly connected to the Internet for remote control and management, wh...

  19. Real-Time Implementation of Islanded Microgrid for Remote Areas

    Jain, Monika; Gupta, Sushma; Masand, Deepika; Agnihotri, Gayatri; Jain, Shailendra

    2016-01-01

    Islanding is a condition in which a microgrid or a portion of power grid, consisting of distributed generation (DG) sources, converter, and load, gets disconnected from the utility grid. Under this condition the DG sources in a microgrid must switch to a voltage control mode, in order to provide constant voltage to local loads. In grid connected mode, the microgrid works as current controller and injects power to the main grid, depending on the power generation and local load with suitable ma...

  20. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.; Sun, Hai

    2015-01-01

    This paper presents a microgrid stability controller (MSC) in order to provide existing distributed generation units (DGs) the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding...

  1. Autonomous economic operation of grid connected DC microgrid

    Nutkani, Inam Ullah; Wang, Peng; Loh, Poh Chiang

    2014-01-01

    This paper presents an autonomous power sharing scheme for economic operation of grid-connected DC microgrid. Autonomous economic operation approach has already been tested for standalone AC microgrids to reduce the overall generation cost and proven a simple and easier to realize compared...... with the centralized management approach. In this paper, the same concept has been extended to grid-connected DC microgrid. The proposed economic droop scheme takes into consideration the power generation cost of Distributed Generators (DGs) and utility grid tariff and adaptively tunes their respective droop curves...... secondary control. The performance of the proposed scheme has been verified for the example grid-connected DC microgrid....

  2. Overview of Multi-DC-Bus Solutions for DC Microgrids

    Ricchiuto, D.; Mastromauro, R.A.; Liserre, Marco

    2013-01-01

    DC Microgrids have recently received a lot of attention in the last years due to high penetration of renewable energy sources as well as distributed energy storage systems. In the future DC microgrids could be preferable respect to AC microgrids in terms of redundancy since multi-DC-Bus solutions...... could provide a continuative power supply to the loads. An overview of Multi-DC-Bus solutions is presented in this paper. The performances are compared on the basis of possible DC microgrid configurations, redundancy, different DC voltage levels....

  3. Application of small modular reactors in modern microgrids

    Islam, M.R., E-mail: mdrazibul.islam@uoit.ca [Univ. of Ontario Inst. of Technology, Oshawa, Ontario (Canada)

    2013-07-01

    Energy supply is one of the most important concerns of every government, energy authority, and researchers to meet the growing regional energy demands. Microgrids have the potential to solve the problem of conventional power grid and offer sustainable decentralized power system. However, most of the current distributed generation within microgrid doesn't meet future energy demand expectations. SMR could an effective and a viable power generation source for modern microgrids to support future electricity demands. A comprehensive study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis. (author)

  4. Application of small modular reactors in modern microgrids

    Islam, M.R.

    2013-01-01

    Energy supply is one of the most important concerns of every government, energy authority, and researchers to meet the growing regional energy demands. Microgrids have the potential to solve the problem of conventional power grid and offer sustainable decentralized power system. However, most of the current distributed generation within microgrid doesn't meet future energy demand expectations. SMR could an effective and a viable power generation source for modern microgrids to support future electricity demands. A comprehensive study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis. (author)

  5. Challenges of Microgrids in Remote Communities: A STEEP Model Application

    Daniel Akinyele

    2018-02-01

    Full Text Available There is a growing interest in the application of microgrids around the world because of their potential for achieving a flexible, reliable, efficient and smart electrical grid system and supplying energy to off-grid communities, including their economic benefits. Several research studies have examined the application issues of microgrids. However, a lack of in-depth considerations for the enabling planning conditions has been identified as a major reason why microgrids fail in several off-grid communities. This development requires research efforts that consider better strategies and framework for sustainable microgrids in remote communities. This paper first presents a comprehensive review of microgrid technologies and their applications. It then proposes the STEEP model to examine critically the failure factors based on the social, technical, economic, environmental and policy (STEEP perspectives. The model details the key dimensions and actions necessary for addressing the challenge of microgrid failure in remote communities. The study uses remote communities within Nigeria, West Africa, as case studies and demonstrates the need for the STEEP approach for better understanding of microgrid planning and development. Better insights into microgrid systems are expected to address the drawbacks and improve the situation that can lead to widespread and sustainable applications in off-grid communities around the world in the future. The paper introduces the sustainable planning framework (SPF based on the STEEP model, which can form a general basis for planning microgrids in any remote location.

  6. Customized electric power storage device for inclusion in a microgrid

    Goldsmith, Steven Y.; Wilson, David; Robinett, III, Rush D.

    2017-08-01

    An electric power storage device included in a microgrid is described herein. The electric power storage device has at least one of a charge rate, a discharge rate, or a power retention capacity that has been customized for the microgrid. The at least one of the charge rate, the discharge rate, or the power retention capacity of the electric power storage device is computed based at least in part upon specified power source parameters in the microgrid and specified load parameters in the microgrid.

  7. Microgrid Design Toolkit (MDT) Technical Documentation and Component Summaries

    Arguello, Bryan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gearhart, Jared Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Katherine A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eddy, John P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    The Microgrid Design Toolkit (MDT) is a decision support software tool for microgrid designers to use during the microgrid design process. The models that support the two main capabilities in MDT are described. The first capability, the Microgrid Sizing Capability (MSC), is used to determine the size and composition of a new microgrid in the early stages of the design process. MSC is a mixed-integer linear program that is focused on developing a microgrid that is economically viable when connected to the grid. The second capability is focused on refining a microgrid design for operation in islanded mode. This second capability relies on two models: the Technology Management Optimization (TMO) model and Performance Reliability Model (PRM). TMO uses a genetic algorithm to create and refine a collection of candidate microgrid designs. It uses PRM, a simulation based reliability model, to assess the performance of these designs. TMO produces a collection of microgrid designs that perform well with respect to one or more performance metrics.

  8. Microgrid Design Toolkit (MDT) User Guide Software v1.2.

    Eddy, John P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-08-01

    The Microgrid Design Toolkit (MDT) supports decision analysis for new ("greenfield") microgrid designs as well as microgrids with existing infrastructure. The current version of MDT includes two main capabilities. The first capability, the Microgrid Sizing Capability (MSC), is used to determine the size and composition of a new, grid connected microgrid in the early stages of the design process. MSC is focused on developing a microgrid that is economically viable when connected to the grid. The second capability is focused on designing a microgrid for operation in islanded mode. This second capability relies on two models: the Technology Management Optimization (TMO) model and Performance Reliability Model (PRM).

  9. Real-time integration of optimal generation scheduling with MPC for the energy management of a renewable hydrogen-based microgrid

    Petrollese, Mario; Valverde, Luis; Cocco, Daniele; Cau, Giorgio; Guerra, José

    2016-01-01

    Highlights: • Energy management strategy for a renewable hydrogen-based microgrid. • Integration of optimal generation scheduling with a model predictive control. • Experimental tests are carried out simulating typical summer and winter days. • Effective improvement in performance and reduction in microgrid operating cost are achieved. - Abstract: This paper presents a novel control strategy for the optimal management of microgrids with high penetration of renewable energy sources and different energy storage systems. The control strategy is based on the integration of optimal generation scheduling with a model predictive control in order to achieve both long and short-term optimal planning. In particular, long-term optimization of the various microgrid components is obtained by the adoption of an optimal generation scheduling, in which a statistical approach is used to take into account weather and load forecasting uncertainties. The real-time management of the microgrid is instead entrusted to a model predictive controller, which has the important feature of using the results obtained by the optimal generation scheduling. The proposed control strategy was tested in a laboratory-scale microgrid present at the University of Seville, which is composed of an electronic power source that emulates a photovoltaic system, a battery bank and a hydrogen production and storage system. Two different experimental tests that simulate a summer and a winter day were carried out over a 24-h period to verify the reliability and performance enhancement of the control system. Results show an effective improvement in performance in terms of reduction of the microgrid operating cost and greater involvement of the hydrogen storage system for the maintenance of a spinning reserve in batteries.

  10. Energy management and multi-layer control of networked microgrids

    Zamora, Ramon

    Networked microgrids is a group of neighboring microgrids that has ability to interchange power when required in order to increase reliability and resiliency. Networked microgrid can operate in different possible configurations including: islanded microgrid, a grid-connected microgrid without a tie-line converter, a grid-connected microgrid with a tie-line converter, and networked microgrids. These possible configurations and specific characteristics of renewable energy offer challenges in designing control and management algorithms for voltage, frequency and power in all possible operating scenarios. In this work, control algorithm is designed based on large-signal model that enables microgrid to operate in wide range of operating points. A combination between PI controller and feed-forward measured system responses will compensate for the changes in operating points. The control architecture developed in this work has multi-layers and the outer layer is slower than the inner layer in time response. The main responsibility of the designed controls are to regulate voltage magnitude and frequency, as well as output power of the DG(s). These local controls also integrate with a microgrid level energy management system or microgrid central controller (MGCC) for power and energy balance for. the entire microgrid in islanded, grid-connected, or networked microgid mode. The MGCC is responsible to coordinate the lower level controls to have reliable and resilient operation. In case of communication network failure, the decentralized energy management will operate locally and will activate droop control. Simulation results indicate the superiority of designed control algorithms compared to existing ones.

  11. Incentive Mechanism of Micro-grid Project Development

    Yong Long

    2018-01-01

    Full Text Available Due to the issue of cost and benefit, the investment demand and consumption demand of micro-grids are insufficient in the early stages, which makes all parties lack motivation to participate in the development of micro-grid projects and leads to the slow development of micro-grids. In order to promote the development of micro-grids, the corresponding incentive mechanism should be designed to motivate the development of micro-grid projects. Therefore, this paper builds a multi-stage incentive model of micro-grid project development involving government, grid corporation, energy supplier, equipment supplier, and the user in order to study the incentive problems of micro-grid project development. Through the solution and analysis of the model, this paper deduces the optimal subsidy of government and the optimal cooperation incentive of the energy supplier, and calculates the optimal pricing strategy of grid corporation and the energy supplier, and analyzes the influence of relevant factors on optimal subsidy and incentive. The study reveals that the cost and social benefit of micro-grid development have a positive impact on micro-grid subsidy, technical level and equipment quality of equipment supplier as well as the fact that government subsidies positively adjust the level of cooperation incentives and price incentives. In the end, the validity of the model is verified by numerical analysis, and the incentive strategy of each participant is analyzed. The research of this paper is of great significance to encourage project development of micro-grids and to promote the sustainable development of micro-grids.

  12. Harmonic mitigation in islanded microgrids by inverter-interfaced distributed energy resource

    Xiongfei Wang

    2012-10-15

    primary droop controllers integrated with virtual output impedance loops and the secondary controllers enabled by the low-bandwidth communication. With the chosen control options of DER inverters, the circulating current characteristics in the droop-controlled parallel three-phase DER inverters are analysed. It is found that the circulating current not only consists of the Positive-Sequence Circulating Current (PSCC) but also contains the Negative-Sequence Circulating Current (NSCC) even when feeding linear balanced loads. It is shown that the presence of the NSCC deteriorates the current quality of inverters and results in unbalanced voltage distortion at certain buses of an islanded microgrid. In order to reduce the NSCC, an improved virtual output impedance loop is proposed, where a negative-sequence virtual resistance is introduced based on the detection of the negative-sequence output current. Moreover, to adapt to the variation of unbalanced loads, a dynamically-tuned negative-sequence resistance is developed. Thus, an autonomous NSCC control that is more suitable for the scattered DER units is achieved and validated via a series of laboratory tests. Under the built islanded microgrid, the control methods of DER inverters for active harmonic conditioning are investigated. Two autonomous harmonic current filtering and resonance damping approaches, i.e. the Resistive-Active Power Filter (R-APF)-based method and the virtual output resistance scheme, are evaluated. It has been found that the large grid-side inductances of DER inverters may lead to either underdamped or aggravated harmonic voltages in the islanded microgrid. To address such a challenge, a Variable Harmonic Impedance (VHI) concept is proposed, where positive resistances and negative inductances are synthesized at the dominant harmonic frequencies. Two case studies, including the single grid-interactive DER inverter and the parallel DER inverters, are carried out. Simulation and laboratory test results are

  13. Multi-Agent System-Based Microgrid Operation Strategy for Demand Response

    Cha, Hee-Jun; Won, Dong-Jun; Kim, Sang-Hyuk; Chung, Il-Yop; Han, Byung-Moon

    2015-01-01

    The microgrid and demand response (DR) are important technologies for future power grids. Among the variety of microgrid operations, the multi-agent system (MAS) has attracted considerable attention. In a microgrid with MAS, the agents installed on the microgrid components operate optimally by communicating with each other. This paper proposes an operation algorithm for the individual agents of a test microgrid that consists of a battery energy storage system (BESS) and an intelligent load. A...

  14. Wind-driven SEIG supplying DC microgrid through a single-stage power converter

    Vellapatchi Nayanar

    2016-09-01

    Full Text Available Nowadays, there is an increased emphasis on utilizing the renewable energy sources and selection of suitable power converters for supplying dc microgrid. Among the various renewable energy sources, wind energy stands first in terms of installed capacity. So, an attempt is made in this paper for supplying dc microgrid utilizing wind energy. A self-excited induction generator has been used in the proposed wind energy conversion system (WECS. A single-stage power converter, namely, semi-converter is connected between the SEIG and dc grid terminals for closed-loop control of the proposed system. A perturb and observe (P&O based maximum power point tracking (MPPT algorithm has been developed and implemented using a dsPIC30F4011 digital controller. In this MPPT algorithm, the firing angle of the converter is adjusted by continuously monitoring the dc grid current for a given wind velocity. For analyzing the proposed system, a MATLAB/Simulink model has been developed by selecting the various components starting from wind-turbine model to the power converter supplying dc microgrid. Successful working of the proposed WECS has also been shown through experimental results obtained on a prototype model developed in the laboratory.

  15. Hybrid Multi-Agent Control in Microgrids: Framework, Models and Implementations Based on IEC 61850

    Xiaobo Dou

    2014-12-01

    Full Text Available Operation control is a vital and complex issue for microgrids. The objective of this paper is to explore the practical means of applying decentralized control by using a multi agent system in actual microgrids and devices. This paper presents a hierarchical control framework (HCF consisting of local reaction control (LRC level, local decision control (LDC level, horizontal cooperation control (HCC level and vertical cooperation control (VCC level to meet different control requirements of a microgrid. Then, a hybrid multi-agent control model (HAM is proposed to implement HCF, and the properties, functionalities and operating rules of HAM are described. Furthermore, the paper elaborates on the implementation of HAM based on the IEC 61850 Standard, and proposes some new implementation methods, such as extended information models of IEC 61850 with agent communication language and bidirectional interaction mechanism of generic object oriented substation event (GOOSE communication. A hardware design and software system are proposed and the results of simulation and laboratory tests verify the effectiveness of the proposed strategies, models and implementations.

  16. Energy Management Strategy for Micro-Grids with PV-Battery Systems and Electric Vehicles

    Jose Luis Torres-Moreno

    2018-02-01

    Full Text Available This paper analyzes the impact of photovoltaic (PV systems on storage and electric vehicles in micro-grids. As these kinds of systems are becoming increasingly popular in the residential sector, the development of a new generation of equipment, such as more efficient batteries or solar panels, makes further study necessary. These systems are especially interesting in commercial or office buildings, since they have a more repetitive daily pattern of electricity consumption, which usually occurs within the maximum solar radiation hours. Based on this need, a novel control strategy aimed at efficiently managing this kind of micro-grid is proposed. The core of this strategy is a rule-based controller managing the power flows between the grid and the batteries of both the PV system and the electric vehicle. Through experimental data and simulations, this strategy was tested under different scenarios. The selected testbed consisted of the laboratory of a research center, which could be easily scalable to the entire building. Results showed the benefits of using an electric vehicle as an active agent in energy balance, leading to a reduction of the energetic costs of a micro-grid.

  17. Feasibility study on small modular reactors for modern microgrids

    Islam, R.; Gabbar, H.A., E-mail: hossam.gabbar@uoit.ca [Univ. of Ontario Inst. of Technology, Faculty of Energy Systems and Nuclear Science, Oshawa, Ontario (Canada)

    2013-07-01

    Microgrid is a solution of conventional power grid problem and offer sustainable decentralized power system. Microgrid with modern distributed energy resources (DER) could play an important role to alleviate dependency on the main electricity grid. Distributed energy resource comprises wind turbine, solar photovoltaic, diesel generator, gas engine, micro turbine, fuel cells, etc.Due to the gap between typical loads and supply within microgrid, larger scale energy generation could provide a possible solution to balance power demand and supply. Feasibility study of Small Nuclear Power Plant, such as Small Modular reactor (SMR), within microgrids could be achieved via different cases. To achieve the target, a comprehensive feasibility study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis.Also potency of SMRs is analyzed. Parameters and Key Performance Indicators (KPIs) could be analyzed to achieve feasible solution of microgrids with small modular reactor (SMR) to improve the overall microgrid performance.The study shows that SMR could be a feasible solution if microgrid parameters are selected properly. (author)

  18. Controller design and stability analysis of grid connected DC microgrid

    Chauhan, Rajeev Kumar; Chauhan, Kalpana; Guerrero, Josep M.

    2018-01-01

    DC microgrids are desired to provide the electricity for the remote areas which are far from the main grid. The microgrid gets popularity because DC power sources such as photovoltaics (PVs), battery banks, and fuel cells can be interconnected without AC/DC converters. The stochastic nature of PV...

  19. A supervisory approach to microgrid demand response and climate control

    Korkas, Christos D.; Baldi, S.; Michailidis, Iakovos; Boutalis, Yiannis; Kosmatopoulos, Elias B.; Antsaklis, Panos J.; Valavanis, Kimon P.; Theiliol, Didier

    2016-01-01

    Microgrids equipped with small-scale renewable-energy generation systems and energy storage units offer challenging opportunity from a control point of view. In fact, in order to improve resilience and enable islanded mode, micro-grid energy management systems must dynamically manage controllable

  20. Distributed EMPC of multiple microgrids for coordinated stochastic energy management

    Kou, Peng; Liang, Deliang; Gao, Lin

    2017-01-01

    Highlights: • Reducing the system wide operating cost compared to the no-cooperation energy management strategy. • Maintaining the supply and demand balance within each microgrid. • Handling the uncertainties in both supply and demand. • Converting the stochastic optimization problems to standard quadratic and linear programming problems. • Achieving a good balance between control performance and computationally feasibility. - Abstract: The concept of multi-microgrids has the potential to improve the reliability and economic performance of a distribution system. To realize this potential, a coordination among multiple microgrids is needed. In this context, this paper presents a new distributed economic model predictive control scheme for the coordinated stochastic energy management of multi-microgrids. By optimally coordinating the operation of individual microgrids, this scheme maintains the system-wide supply and demand balance in an economical manner. Based on the probabilistic forecasts of renewable power generation and microgrid load, this scheme effectively handles the uncertainties in both supply and demand. Using the Chebyshev inequality and the Delta method, the corresponding stochastic optimization problems have been converted to quadratic and linear programs. The proposed scheme is evaluated on a large-scale case that includes ten interconnected microgrids. The results indicated that the proposed scheme successfully reduces the system wide operating cost, achieves the supply-demand balance in each microgrid, and brings the energy exchange between DNO and main grid to a predefined trajectory.

  1. Dynamic performance enhancement of microgrids by advanced sliding mode controller

    Sofla, Mohammadhassan Abdollahi [Electrical Engineering and Computer Science Dept., University of Toledo, Ohio (United States); Gharehpetian, Gevorg B. [Electrical Engineering Dept., Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2011-01-15

    Dynamics are the most important problems in the microgrid operation. In the islanded microgrid, the mismatch of parallel operations of inverters during dynamics can result in the instability. This paper considers severe dynamics which can occur in the microgrid. Microgrid can have different configurations with different load and generation dynamics which are facing voltage disturbances. As a result, microgrid has many uncertainties and is placed in the distribution network where is full of voltage disturbances. Moreover, characteristics of the distribution network and distributed energy resources in the islanded mode make microgrid vulnerable and easily lead to instability. The main aim of this paper is to discuss the suitable mathematical modeling based on microgrid characteristics and to design properly inner controllers to enhance the dynamics of microgrid with uncertain and changing parameters. This paper provides a method for inner controllers of inverter-based distributed energy resources to have a suitable response for different dynamics. Parallel inverters in distribution networks were considered to be controlled by nonlinear robust voltage and current controllers. Theoretical prove beyond simulation results, reveal evidently the effectiveness of the proposed controller. (author)

  2. Cost-Prioritized Droop Schemes for Autonomous AC Microgrids

    Nutkani, Inam Ullah; Loh, Poh Chiang; Wang, Peng

    2015-01-01

    This paper presents two cost-prioritized droop sche- mes for distributed generators (DGs) in a rural or islanded microgrid. Dispatch prioritization of the schemes allows autonomous identification of the appropriate DGs for generation, in accordance to the overall load conditions of the microgrid....

  3. Microgrid-Ready Solar PV - Planning for Resiliency

    Booth, Samuel S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-10-17

    This fact sheet provides background information on microgrids with suggested language for several up-front considerations that can be added to a solar project procurement or request for proposal (RFP) that will help ensure that PV systems are built for future microgrid connection.

  4. Stochastic Modeling and Optimization in a Microgrid: A Survey

    Hao Liang

    2014-03-01

    Full Text Available The future smart grid is expected to be an interconnected network of small-scale and self-contained microgrids, in addition to a large-scale electric power backbone. By utilizing microsources, such as renewable energy sources and combined heat and power plants, microgrids can supply electrical and heat loads in local areas in an economic and environment friendly way. To better adopt the intermittent and weather-dependent renewable power generation, energy storage devices, such as batteries, heat buffers and plug-in electric vehicles (PEVs with vehicle-to-grid systems can be integrated in microgrids. However, significant technical challenges arise in the planning, operation and control of microgrids, due to the randomness in renewable power generation, the buffering effect of energy storage devices and the high mobility of PEVs. The two-way communication functionalities of the future smart grid provide an opportunity to address these challenges, by offering the communication links for microgrid status information collection. However, how to utilize stochastic modeling and optimization tools for efficient, reliable and economic planning, operation and control of microgrids remains an open issue. In this paper, we investigate the key features of microgrids and provide a comprehensive literature survey on the stochastic modeling and optimization tools for a microgrid. Future research directions are also identified.

  5. SMART FUEL CELL OPERATED RESIDENTIAL MICRO-GRID COMMUNITY

    Dr. Mohammad S. Alam (PI/PD)

    2005-04-13

    To build on the work of year one by expanding the smart control algorithm developed to a micro-grid of ten houses; to perform a cost analysis; to evaluate alternate energy sources; to study system reliability; to develop the energy management algorithm, and to perform micro-grid software and hardware simulations.

  6. Stochastic Predictive Control of Multi-Microgrid Systems

    Bazmohammadi, Najmeh; Tahsiri, Ahmadreza; Anvari-Moghaddam, Amjad

    2018-01-01

    This paper presents a stochastic predictive control algorithm for a number of microgrids connected to the same distribution system. Each microgrid includes a variety of distributed resources such as wind turbine, photo voltaic units, energy storage devices and loads. Considering the uncertainty...

  7. Power flow analysis for DC voltage droop controlled DC microgrids

    Li, Chendan; Chaudhary, Sanjay; Dragicevic, Tomislav

    2014-01-01

    This paper proposes a new algorithm for power flow analysis in droop controlled DC microgrids. By considering the droop control in the power flow analysis for the DC microgrid, when compared with traditional methods, more accurate analysis results can be obtained. The algorithm verification is ca...

  8. Optimization of microgrids based on controller designing for ...

    The power quality of microgrid during islanded operation is strongly related with the controller performance of DGs. Therefore a new optimal control strategy for distributed generation based inverter to connect to the generalized microgrid is proposed. This work shows developing optimal control algorithms for the DG ...

  9. Feasibility study on small modular reactors for modern microgrids

    Islam, R.; Gabbar, H.A.

    2013-01-01

    Microgrid is a solution of conventional power grid problem and offer sustainable decentralized power system. Microgrid with modern distributed energy resources (DER) could play an important role to alleviate dependency on the main electricity grid. Distributed energy resource comprises wind turbine, solar photovoltaic, diesel generator, gas engine, micro turbine, fuel cells, etc.Due to the gap between typical loads and supply within microgrid, larger scale energy generation could provide a possible solution to balance power demand and supply. Feasibility study of Small Nuclear Power Plant, such as Small Modular reactor (SMR), within microgrids could be achieved via different cases. To achieve the target, a comprehensive feasibility study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis.Also potency of SMRs is analyzed. Parameters and Key Performance Indicators (KPIs) could be analyzed to achieve feasible solution of microgrids with small modular reactor (SMR) to improve the overall microgrid performance.The study shows that SMR could be a feasible solution if microgrid parameters are selected properly. (author)

  10. Decentralized Coordinated Control Strategy of Islanded Microgrids

    Wu, Dan

    as grid voltage/frequency regulation. In order to enhance the reliability of overall islanded Microgrid operation, basic functions of coordinated control which taking into account the state of charge (SoC) limitation and power availability of renewable energy sources is implemented in a distributed level...... control strategies in this thesis, in order to promote the decentralization of the overall system. Especially the consensus algorithm based secondary level is investigated in the thesis in order to simplify the communication configuration which only flood information through the neighboring units......Facing the challenges brought by the traditional large power system concerning the environmental and economic issues, along recent years distributed generation is considered as an alternative solution to provide clean energy in a local manner. In this context, Microgrid which performing as a local...

  11. Hybrid fuel cells technologies for electrical microgrids

    San Martin, Jose Ignacio; Zamora, Inmaculada; San Martin, Jose Javier; Aperribay, Victor; Eguia, Pablo [Department of Electrical Engineering, University of the Basque Country, Alda. de Urquijo, s/n, 48013 Bilbao (Spain)

    2010-09-15

    Hybrid systems are characterized by containing two or more electrical generation technologies, in order to optimize the global efficiency of the processes involved. These systems can present different operating modes. Besides, they take into account aspects that not only concern the electrical and thermal efficiencies, but also the reduction of pollutant emissions. There is a wide range of possible configurations to form hybrid systems, including hydrogen, renewable energies, gas cycles, vapour cycles or both. Nowadays, these technologies are mainly used for energy production in electrical microgrids. Some examples of these technologies are: hybridization processes of fuel cells with wind turbines and photovoltaic plants, cogeneration and trigeneration processes that can be configured with fuel cell technologies, etc. This paper reviews and analyses the main characteristics of electrical microgrids and the systems based on fuel cells for polygeneration and hybridization processes. (author)

  12. Power Oscillations Damping in DC Microgrids

    Hamzeh, Mohsen; Ghafouri, Mohsen; Karimi, Houshang

    2016-01-01

    This paper proposes a new control strategy for damping of power oscillations in a multi-source dc microgrid. A parallel combination of a fuel cell (FC), a photovoltaic (PV) system and a supercapacitor (SC) are used as a hybrid power conversion system (HPCS). The SC compensates for the slow transi...... of the proposed control scheme is verified using hardware-in-the-loop (HIL) simulations carried out in OPAL-RT technologies....

  13. LWIR Microgrid Polarimeter for Remote Sensing Studies

    2010-02-28

    Polarimeter for Remote Sensing Studies 5b. GRANT NUMBER FA9550-08-1-0295 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 1. Scott Tyo 5e. TASK...and tested at the University of Arizona, and preliminary images are shown in this final report. 15. SUBJECT TERMS Remote Sensing , polarimetry 16...7.0 LWIR Microgrid Polarimeter for Remote Sensing Studies J. Scott Tyo College of Optical Sciences University of Arizona Tucson, AZ, 85721 tyo

  14. Economic energy distribution and consumption in a microgrid Part 2

    Tahersima, Fatemeh; Stoustrup, Jakob; Andersen, Palle

    2014-01-01

    Energy management of a small scale electrical microgrid is investigated. The microgrid comprises residential houses with local renewable generation, consumption and storage units. The microgrid has the possibility of connection to the electricity grid as well to compensate energy decit of local...... power producers. The nal objective is to full the microgrid's energy demands mainly from the local electricity producers. The other objective is to manage power consumption such that the consumption cost is minimum for individual households. In this study, a hierarchical controller composed of three...... levels is proposed. Each layer from bottom to top focus on individual energy consuming units, individual buildings, and the microgrid respectively. At the middle layer, a model predictive controller is formulated to schedule the building's energy consumption using potential load exibilities. The top...

  15. Autonomous Operation of Hybrid Microgrid With AC and DC Subgrids

    Chiang Loh, Poh; Li, Ding; Kang Chai, Yi

    2013-01-01

    sources distributed throughout the two types of subgrids, which is certainly tougher than previous efforts developed for only ac or dc microgrid. This wider scope of control has not yet been investigated, and would certainly rely on the coordinated operation of dc sources, ac sources, and interlinking...... converters. Suitable control and normalization schemes are now developed for controlling them with the overall hybrid microgrid performance already verified in simulation and experiment.......This paper investigates on power-sharing issues of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac subgrids interconnected by power electronic interfaces. The main challenge here is to manage power flows among all...

  16. Synchronisation of two separate zones in a standalone microgrid

    Ying-Yi Hong

    2017-06-01

    Full Text Available Standalone microgrids that comprise distributed generation sources (DGSs or energy storage systems (ESSs exist on off-shore islands or remote areas. When a fault occurs in a standalone microgrid, the microgrid is separated into several zones with pre-specified DGS or ESS supplying power to local loads. After the fault is cleared, the three-phase voltages and frequencies may differ among these zones. To restore the original microgrid topology, these zones must be reconnected to each other by synchronisation. A synchronisation controller of the DGS/ESS that accounts for slightly different three-phase voltages and frequencies in two separate zones is presented. The Clark transform and Mamdani fuzzy rules are used to implement the controller, providing fast and seamless synchronisation. Simulation results using a standalone microgrid show the practical applicability of the proposed method.

  17. Autonomous operation of distributed storages in microgrids

    Loh, Poh Chiang; Chai, Yi Kai; Li, Ding

    2014-01-01

    Operation of distributed generators in microgrids has been widely discussed, but would not be fully autonomous if distributed energy storages are not considered. Storages are important since they provide energy buffering to load changes, energy levelling to source variations and ride-through enha......Operation of distributed generators in microgrids has been widely discussed, but would not be fully autonomous if distributed energy storages are not considered. Storages are important since they provide energy buffering to load changes, energy levelling to source variations and ride......-through enhancement to the microgrids. Recognising their importance, this study presents a scheme for sharing power among multiple distributed storages in coordination with the distributed sources and loads. The scheme prompts the storages to autonomously sense for local operating conditions, requesting for maximum...... to help with meeting the extra load demand. The described process takes place autonomously with energy eventually shared among the storages in proportion to their ratings. To test the concepts discussed, experiments have been performed with favourable results obtained for performance verification....

  18. Microgrids: Energy management by loss minimization technique

    Basu, A.K. [Electrical Engineering Dept., Jadavpur University & 20/2, Khanpur Road, Kolkata 700047 (India); Chowdhury, S.; Chowdhury, S.P. [Electrical Engineering Department, University of Cape Town & Private Bag X3, Menzies Building, Room-517, Rondebosch, Cape Town 7701 (India)

    2011-07-01

    Energy management is a techno-economic issue, which dictates, in the context of microgrids, how optimal investment in technology front could bring optimal power quality and reliability (PQR) of supply to the consumers. Investment in distributed energy resources (DERs), with their connection to the utility grid at optimal locations and with optimal sizes, saves energy in the form of line loss reduction. Line loss reduction is the indirect benefit to the microgrid owner who may recover it as an incentive from utility. The present paper focuses on planning of optimal siting and sizing of DERs based on minimization of line loss. Optimal siting is done, here, on the loss sensitivity index (LSI) method and optimal sizing by differential evolution (DE) algorithms, which is, again, compared with particle swarm optimization (PSO) technique. Studies are conducted on 6-bus and 14-bus radial networks under islanded mode of operation with electric demand profile. Islanding helps planning of DER capacity of microgrid, which is self-sufficient to cater its own consumers without utility's support.

  19. Auction Mechanism of Micro-Grid Project Transfer

    Yong Long

    2017-10-01

    Full Text Available Micro-grid project transfer is the primary issue of micro-grid development. The efficiency and quality of the micro-grid project transfer directly affect the quality of micro-grid project construction and development, which is very important for the sustainable development of micro-grid. This paper constructs a multi-attribute auction model of micro-grid project transfer, which reflects the characteristics of micro-grid system and the interests of stakeholders, calculates the optimal bidding strategy and analyzes the influence of relevant factors on auction equilibrium by multi-stage dynamic game with complete information, and makes a numerical simulation analysis. Results indicate that the optimal strategy of auction mechanism is positively related to power quality, energy storage quality, and carbon emissions. Different from the previous lowest price winning mechanism, the auction mechanism formed in this paper emphasizes that the energy suppliers which provide the comprehensive optimization of power quality, energy storage quality, carbon emissions, and price will win the auction, when both the project owners and energy suppliers maximize their benefits under this auction mechanism. The auction mechanism is effective because it is in line with the principle of individual rationality and incentive compatibility. In addition, the number of energy suppliers participating in the auction and the cost of the previous auction are positively related to the auction equilibrium, both of which are adjusting the equilibrium results of the auction. At the same time, the utilization rate of renewable energy and the comprehensive utilization of energy also have a positive impact on the auction equilibrium. In the end, this paper puts forward a series of policy suggestions about micro-grid project auction. The research in this paper is of great significance to improve the auction quality of micro-grid projects and promote the sustainable development of micro-grid.

  20. dc Arc Fault Effect on Hybrid ac/dc Microgrid

    Fatima, Zahra

    The advent of distributed energy resources (DER) and reliability and stability problems of the conventional grid system has given rise to the wide spread deployment of microgrids. Microgrids provide many advantages by incorporating renewable energy sources and increasing the reliability of the grid by isolating from the main grid in case of an outage. AC microgrids have been installed all over the world, but dc microgrids have been gaining interest due to the advantages they provide over ac microgrids. However the entire power network backbone is still ac and dc microgrids require expensive converters to connect to the ac power network. As a result hybrid ac/dc microgrids are gaining more attention as it combines the advantages of both ac and dc microgrids such as direct integration of ac and dc systems with minimum number of conversions which increases the efficiency by reducing energy losses. Although dc electric systems offer many advantages such as no synchronization and no reactive power, successful implementation of dc systems requires appropriate protection strategies. One unique protection challenge brought by the dc systems is dc arc faults. A dc arc fault is generated when there is a gap in the conductor due to insulation degradation and current is used to bridge the gap, resulting in an arc with very high temperature. Such a fault if it goes undetected and is not extinguished can cause damage to the entire system and cause fires. The purpose of the research is to study the effect of the dc arc fault at different locations in the hybrid ac/dc microgrid and provide insight on the reliability of the grid components when it is impacted by arc faults at various locations in the grid. The impact of dc arc fault at different locations on the performance of the PV array, wind generation, and constant power loads (CPL) interfaced with dc/dc converters is studied. MATLAB/Simulink is used to model the hybrid ac/dc microgrid and arc fault.

  1. Protection of Renewable-dominated Microgrids: Challenges and Potential Solutions.

    Elkhatib, Mohamed; Ellis, Abraham; Milan Biswal; Sukumar Brahma; Satish Ranade

    2016-11-01

    keywords : Microgrid Protection, Impedance Relay, Signal Processing-based Fault Detec- tion, Networked Microgrids, Communication-Assisted Protection In this report we address the challenge of designing efficient protection system for inverter- dominated microgrids. These microgrids are characterised with limited fault current capacity as a result of current-limiting protection functions of inverters. Typically, inverters limit their fault contribution in sub-cycle time frame to as low as 1.1 per unit. As a result, overcurrent protection could fail completely to detect faults in inverter-dominated microgrids. As part of this project a detailed literature survey of existing and proposed microgrid protection schemes were conducted. The survey concluded that there is a gap in the available microgrid protection methods. The only credible protection solution available in literature for low- fault inverter-dominated microgrids is the differential protection scheme which represents a robust transmission-grade protection solution but at a very high cost. Two non-overcurrent protection schemes were investigated as part of this project; impedance-based protection and transient-based protection. Impedance-based protection depends on monitoring impedance trajectories at feeder relays to detect faults. Two communication-based impedance-based protection schemes were developed. the first scheme utilizes directional elements and pilot signals to locate the fault. The second scheme depends on a Central Protection Unit that communicates with all feeder relays to locate the fault based on directional flags received from feeder relays. The later approach could potentially be adapted to protect networked microgrids and dynamic topology microgrids. Transient-based protection relies on analyzing high frequency transients to detect and locate faults. This approach is very promising but its implementation in the filed faces several challenges. For example, high frequency transients due to

  2. Microgrid Central Controller Development and Hierarchical Control Implementation in the Intelligent MicroGrid Lab of Aalborg University

    Meng, Lexuan; Savaghebi, Mehdi; Andrade, Fabio

    2015-01-01

    This paper presents the development of a microgrid central controller in an inverter-based intelligent microgrid (iMG) lab in Aalborg University, Denmark. The iMG lab aims to provide a flexible experimental platform for comprehensive studies of microgrids. The complete control system applied...... in this lab is based on the hierarchical control scheme for microgrids and includes primary, secondary and tertiary control. The structure of the lab, including the lab facilities, configurations and communication network, is first introduced. Primary control loops are developed in MATLAB....../Simulink and compiled to dSPACEs for local control purposes. In order to realize system supervision and proper secondary and tertiary management, a LabVIEW-based microgrid central controller is also developed. The software and hardware schemes are described. An example case is introduced and tested in the iMG lab...

  3. MicroGrid modelling and online management

    Mohamed, F.A.

    2008-07-01

    Modern power network owners have to respond to a number of challenges such as significant load changes and growth in the geographical distribution of the customers. On the other hand, the environmental policy and economic requirements from the market are constantly growing. The presence of these problems has led to an increased interest in the local renewable energy generation at the distribution level. The Microgrid (MG) concept assumes a cluster of loads and microsources operating as a single controllable system that provides both power and heat to its local area. Not much is known about Microgrid behavior as a whole system. Some models exist which describe the components of the Microgrid. This thesis aims to model Microgrids at steady state and study their transient responses to changing inputs. Currently models of a Diesel Engine, a Fuel Cell, a Microturbine, a Windturbine, a Photovoltaic cell, and Battery storage have been developed. In this thesis, a generalized formulation is introduced to determine the optimal operating strategy, the goal to minimize the operating costs as well as the reduction of the emission costs and level for a MicroGrid. To solve such a management problem it is first formulated as a nonlinear constrained cost optimization problem. Since the management problem poses a number of simultaneous objectives and constraints a Multiobjective optimization problem is formulated by considering the emission level reduction. A daily income from sold power and cost to be paid to the utility of the purchased power is added to the problem. The model takes also into consideration the reduction of emissions caused by NO{sub x}, SO{sub 2} and CO{sub 2}. The optimization is aimed to minimize the operating costs of the system, while constraints are adjusted to meet the customer demand and the safety of the system. Different optimization techniques are applied to solve the problem, such as Mesh Adaptive Direct Search, Sequential Quadratic Programming

  4. Interconnecting Microgrids via the Energy Router with Smart Energy Management

    Yingshu Liu

    2017-08-01

    Full Text Available A novel and flexible interconnecting framework for microgrids and corresponding energy management strategies are presented, in response to the situation of increasing renewable-energy penetration and the need to alleviate dependency on energy storage equipment. The key idea is to establish complementary energy exchange between adjacent microgrids through a multiport electrical energy router, according to the consideration that adjacent microgrids may differ substantially in terms of their patterns of energy production and consumption, which can be utilized to compensate for each other’s instant energy deficit. Based on multiport bidirectional voltage source converters (VSCs and a shared direct current (DC power line, the energy router serves as an energy hub, and enables flexible energy flow among the adjacent microgrids and the main grid. The analytical model is established for the whole system, including the energy router, the interconnected microgrids and the main grid. Various operational modes of the interconnected microgrids, facilitated by the energy router, are analyzed, and the corresponding control strategies are developed. Simulations are carried out on the Matlab/Simulink platform, and the results have demonstrated the validity and reliability of the idea for microgrid interconnection as well as the corresponding control strategies for flexible energy flow.

  5. An Intelligent Multiagent System for Autonomous Microgrid Operation

    Tetsuo Kinoshita

    2012-09-01

    Full Text Available A microgrid is an eco-friendly power system because renewable sources such as solar and wind power are used as the main power sources. For this reason, much research, development, and demonstration projects have recently taken place in many countries. Operation is one of the important research topics for microgrids. For efficient and economical microgrid operation, a human operator is required as in other power systems, but it is difficult because there are some restrictions related to operation costs and privacy issues. To overcome the restriction, autonomous operation for microgrids is required. Recently, an intelligent agent system for autonomous microgrid operation has been studied as a potential solution. This paper proposes a multiagent system for autonomous microgrid operation. To build the multiagent system, the functionalities of agents, interactions among agents, and an effective agent protocol have been designed. The proposed system has been implemented by using an ADIPS/DASH framework as an agent platform. The intelligent multiagent system for microgrid operation based on the proposed scheme is tested to show the functionality and feasibility on a distributed environment through the Internet.

  6. Microgrid optimal scheduling considering impact of high penetration wind generation

    Alanazi, Abdulaziz

    The objective of this thesis is to study the impact of high penetration wind energy in economic and reliable operation of microgrids. Wind power is variable, i.e., constantly changing, and nondispatchable, i.e., cannot be controlled by the microgrid controller. Thus an accurate forecasting of wind power is an essential task in order to study its impacts in microgrid operation. Two commonly used forecasting methods including Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Network (ANN) have been used in this thesis to improve the wind power forecasting. The forecasting error is calculated using a Mean Absolute Percentage Error (MAPE) and is improved using the ANN. The wind forecast is further used in the microgrid optimal scheduling problem. The microgrid optimal scheduling is performed by developing a viable model for security-constrained unit commitment (SCUC) based on mixed-integer linear programing (MILP) method. The proposed SCUC is solved for various wind penetration levels and the relationship between the total cost and the wind power penetration is found. In order to reduce microgrid power transfer fluctuations, an additional constraint is proposed and added to the SCUC formulation. The new constraint would control the time-based fluctuations. The impact of the constraint on microgrid SCUC results is tested and validated with numerical analysis. Finally, the applicability of proposed models is demonstrated through numerical simulations.

  7. Effect of Heat and Electricity Storage and Reliability on Microgrid Viability:A Study of Commercial Buildings in California and New York States

    Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy; Coffey, Brian; Aki, Hirohisa

    2008-12-01

    In past work, Berkeley Lab has developed the Distributed Energy Resources Customer Adoption Model (DER-CAM). Given end-use energy details for a facility, a description of its economic environment and a menu of available equipment, DER-CAM finds the optimal investment portfolio and its operating schedule which together minimize the cost of meeting site service, e.g., cooling, heating, requirements. Past studies have considered combined heat and power (CHP) technologies. Methods and software have been developed to solve this problem, finding optimal solutions which take simultaneity into account. This project aims to extend on those prior capabilities in two key dimensions. In this research storage technologies have been added as well as power quality and reliability (PQR) features that provide the ability to value the additional indirect reliability benefit derived from Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid capability. This project is intended to determine how attractive on-site generation becomes to a medium-sized commercial site if economical storage (both electrical and thermal), CHP opportunities, and PQR benefits are provided in addition to avoiding electricity purchases. On-site electrical storage, generators, and the ability to seamlessly connect and disconnect from utility service would provide the facility with ride-through capability for minor grid disturbances. Three building types in both California and New York are assumed to have a share of their sensitive electrical load separable. Providing enhanced service to this load fraction has an unknown value to the facility, which is estimated analytically. In summary, this project began with 3 major goals: (1) to conduct detailed analysis to find the optimal equipment combination for microgrids at a few promising commercial building hosts in the two favorable markets of California and New York; (2) to extend the analysis capability of DER-CAM to include both heat and

  8. Tests at constant extension velocity CERT for the evaluation of environmental assisted cracking; Pruebas a velocidad de extension constante CERT, para evaluar el agrietamiento asistido por el ambiente (EAC)

    Arganis J, C R [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico)

    1994-12-31

    The test at constant velocity extension (CERT) is firmly established as a technique for the study of environmentally cracking (stress corrosion and hydrogen embrittlement) and is widely used, mainly in mechanistic studies. In CERT test, an increasing charge is applied to a sample and the extension velocity is hold up constant to allow that corrosion interplay in the process. The type of crack and ductility measurements with the conditions for testing are compared with a cracked sample in an inert media. Required equipment: (1) A charge mechanism capable to control the elongation of test samples in a rank of 1 x 10{sup -5} to 1 x 10{sup -7} inch/inch sec and capable to hold up constant such elongation. (2) A suitable standard (Astm standard A-370). (3) A chamber or cell for the media in which the chemical composition of the solution, the gas composition, the pressure, temperature and electrochemical potential can be controlled in order to simulate with anticipation the service conditions. The cell must allow the mechanical access of the test sample to the charge train of the machine. (Author).

  9. Adaptive control for evaluation of flexibility benefits in microgrid systems

    Holjevac, Ninoslav; Capuder, Tomislav; Kuzle, Igor

    2015-01-01

    Aggregating groups of loads and generators at the same location with centralized control is known as the concept of microgrids. However, if those flexible producers and consumers do not have the ability to balance the variability and uncertainty of RES (renewable energy sources) production within them, from the system perspective they are seen as a source of imbalances and potential problems in maintaining the equilibrium of production and consumption. The papers main goal is to quantify the ability of microgrid components to provide flexibility. This flexibility is analysed from two perspectives, defining two operating principles of each microgrid: independently from the distribution grid and connected, interacting and responding to signals from the upstream system. Following on this, the paper presents two relevant cases. In the first part a deterministic model is developed based on MILP (Mixed Integer Linear programming) simulating the microgrid operation over one year period. This model is used to determine the optimal microgrid configuration with respect to the amount of unused energy, thus defining role and capability of different pieces of equipment and their size (RES (renewable energy sources) wind and solar, HS (heat storage), μCHP (micro combined heat and power plants) and EHP (electric heat pumps)). The second part of this paper further expands the model with MPC (Model Predictive Control) approach in order to capture the behaviour of microgrid interaction with the distribution grid, modelling uncertainties of forecasting RES production by stochastic programming. The model is capable to evaluate both the impact of variable energy production and consumption and the impact of energy balancing tariffs depending on the amount of balancing energy needed for the microgrid operation. - Highlights: • Integrated MILP (Mixed Integer Linear programming) formulation for optimal operation of developed microgrid model. • Determining operational flexibility of

  10. Customized electric power storage device for inclusion in a collective microgrid

    Robinett, III, Rush D.; Wilson, David G.; Goldsmith, Steven Y.

    2016-02-16

    An electric power storage device is described herein, wherein the electric power storage device is included in a microgrid. The electric power storage device has at least one of a charge rate, a discharge rate, or a power retention capacity that has been customized for a collective microgrid. The collective microgrid includes at least two connected microgrids. The at least one of the charge rate, the discharge rate, or the power retention capacity of the electric power storage device is computed based at least in part upon specified power source parameters in the at least two connected microgrids and specified load parameters in the at least two connected microgrids.

  11. Stokes image reconstruction for two-color microgrid polarization imaging systems.

    Lemaster, Daniel A

    2011-07-18

    The Air Force Research Laboratory has developed a new microgrid polarization imaging system capable of simultaneously reconstructing linear Stokes parameter images in two colors on a single focal plane array. In this paper, an effective method for extracting Stokes images is presented for this type of camera system. It is also shown that correlations between the color bands can be exploited to significantly increase overall spatial resolution. Test data is used to show the advantages of this approach over bilinear interpolation. The bounds (in terms of available reconstruction bandwidth) on image resolution are also provided.

  12. A Hybrid Algorithm for Fault Locating in Looped Microgrids

    Beheshtaein, Siavash; Savaghebi, Mehdi; Quintero, Juan Carlos Vasquez

    2016-01-01

    Protection is the last obstacle to realizing the idea of microgrid. Some of the main challenges in microgrid protection include topology changes of microgrid, week-infeed fault, bidirectional power flow effects, blinding of the protection, sympathetic tripping, high impedance fault, and low voltage...... ride through (LVRT). Besides these challenges, it is desired to eliminate the relays for distribution lines and locate faults based on distributed generations (DGs) voltage or current. On the other hands increasing in the number of DGs and lines would result in high computation burden and degradation...

  13. Analysis of Droop Controlled Parallel Inverters in Islanded Microgrids

    Mariani, Valerio; Vasca, Francesco; Guerrero, Josep M.

    2014-01-01

    Three-phase droop controlled inverters are widely used in islanded microgrids to interface distributed energy resources and to provide for the loads active and reactive powers demand. The assessment of microgrids stability, affected by the control and line parameters, is a stringent issue....... This paper shows a systematic approach to derive a closed loop model of the microgrid and then to perform an eigenvalues analysis that highlights how the system’s parameters affect the stability of the network. It is also shown that by means of a singular perturbation approach the resulting reduced order...

  14. Optimal Power Flow in Microgrids with Energy Storage

    Levron, Yoash; Guerrero, Josep M.; Beck, Yuval

    2013-01-01

    Energy storage may improve power management in microgrids that include renewable energy sources. The storage devices match energy generation to consumption, facilitating a smooth and robust energy balance within the microgrid. This paper addresses the optimal control of the microgrid’s energy...... storage devices. Stored energy is controlled to balance power generation of renewable sources to optimize overall power consumption at the microgrid point of common coupling. Recent works emphasize constraints imposed by the storage device itself, such as limited capacity and internal losses. However...

  15. PSO Algorithm for an Optimal Power Controller in a Microgrid

    Al-Saedi, W.; Lachowicz, S.; Habibi, D.; Bass, O.

    2017-07-01

    This paper presents the Particle Swarm Optimization (PSO) algorithm to improve the quality of the power supply in a microgrid. This algorithm is proposed for a real-time selftuning method that used in a power controller for an inverter based Distributed Generation (DG) unit. In such system, the voltage and frequency are the main control objectives, particularly when the microgrid is islanded or during load change. In this work, the PSO algorithm is implemented to find the optimal controller parameters to satisfy the control objectives. The results show high performance of the applied PSO algorithm of regulating the microgrid voltage and frequency.

  16. Fault Analysis and Detection in Microgrids with High PV Penetration

    El Khatib, Mohamed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez Alvidrez, Javier [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    In this report we focus on analyzing current-controlled PV inverters behaviour under faults in order to develop fault detection schemes for microgrids with high PV penetration. Inverter model suitable for steady state fault studies is presented and the impact of PV inverters on two protection elements is analyzed. The studied protection elements are superimposed quantities based directional element and negative sequence directional element. Additionally, several non-overcurrent fault detection schemes are discussed in this report for microgrids with high PV penetration. A detailed time-domain simulation study is presented to assess the performance of the presented fault detection schemes under different microgrid modes of operation.

  17. A Game Changer: Electrifying Remote Communities by Using Isolated Microgrids

    Lu, Xiaonan; Wang, Jianhui

    2017-06-01

    Microgrids, as self-contained entities, are of increasing interest in modern electric grids. Microgrids provide a sustainable solution to aggregate distributed energy resources (DERs) [e.g., photovoltaics (PVs), wind turbines], energy storage, and loads in a localized manner, especially in distribution systems. As a controllable unit, a microgrid can manage and balance the source and load power inside it to ensure stable and reliable operation. Moreover, through coordination with upper-level control systems, it can be dispatched and respond to the control commands issued by the central controller in the distribution system-in other words, a system that is effectively a distribution management system (DMS).

  18. Increasing Resiliency Through Renewable Energy Microgrids

    Anderson, Katherine H [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DiOrio, Nicholas A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cutler, Dylan S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Butt, Robert S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Richards, Allison [unaffiliated

    2017-08-01

    This paper describes a methodology to quantify the economic and resiliency benefit provided by renewable energy (RE) in a hybrid RE-storage-diesel microgrid. We present a case study to show how this methodology is applied to a multi-use/ multi-function telecommunications facility in southern California. In the case study, we first identify photovoltaic (PV) and battery energy storage system (BESS) technologies that minimize the lifecycle cost of energy at the site under normal, grid-connected operation. We then evaluate how those technologies could be incorporated alongside existing diesel generators in a microgrid to increase resiliency at the site, where resiliency is quantified in terms of the amount of time that the microgrid can sustain the critical load during a grid outage. We find that adding PV and BESS to the existing backup diesel generators with a fixed fuel supply extends the amount of time the site could survive an outage by 1.8 days, from 1.7 days for the existing diesel-only backup system to 3.5 days for the PV/diesel/BESS hybrid system. Furthermore, even after diesel fuel supplies are exhausted, the site can continue to operate critical loads during daytime hours using just the PV/BESS when there is sufficient solar resource. We find that the site can save approximately $100,000 in energy costs over the 25-year lifecycle while doubling the amount of time they can survive an outage. The methodology presented here provides a template for increasing resiliency at telecomm sites by implementing renewable energy solutions, which provide additional benefits of carbon emission reduction and energy cost savings.

  19. [Implementation of the EndoCert system for certification of arthroplasty centers. Experiences from the pilot phase].

    Haas, H; Mittelmeier, W

    2014-06-01

    EndoCert is an initiative of the Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie (DGOOC, German Society for Orthopedics and Orthopedic Surgery) which has been available since October 2012 and is the first system worldwide for certification of specialized arthroplasty centers. Before implementation of this certification concept two sequential pilot phases were carried out with representative treatment institutions. The results from these pilot clinics are presented with respect to quality improvement effects. Early effects on the quality of treatment have been achieved by rectification of nonconformities determined in the audit with respect to structural and process quality. A total of 172 nonconformities found in the 23 participating pilot clinics could be rectified. Long-term effects on the quality of results will in future be analyzed in cooperation with the German endoprosthesis register (EPRD) and by accompanying evaluations. A close feedback of the collated experiences and results to the certification committee, which is responsible for the procedure together with the DGOOC, allows continuous further development of the system EndoCert represents a substantial step towards a nationwide safety and improvement of the quality in arthroplasty treatment within the preoperative, perioperative and postoperative framework and can in future represent a decisive tool together with the EPRD in quality management.

  20. Intelligent Power Control of DC Microgrid

    Hajizadeh, Amin; N. Soltani, Mohsen; Norum, Lars

    2017-01-01

    In this paper, an intelligent power management strategy is proposed for hybrid DC microgrid, including wind turbine, fuel cell and battery energy storage. The considered wind turbine has a permanent magnet synchronous generator (PMSG). In the considered structure, wind turbine operates as the main...... condition and fuel cell will not generate excessive power. The proposed control scheme is based on the fuzzy algorithm. All simulations in variant operational modes are performed by MATLAB/Simulink and results show the effectiveness of the proposed control strategy....

  1. Power Oscillations Damping in DC Microgrids

    Hamzeh, Mohsen; Ghafouri, Mohsen; Karimi, Houshang; Sheshyekani, Keyhan; Guerrero, Josep M.

    2016-01-01

    This paper proposes a new control strategy for damping of power oscillations in a multi-source dc microgrid. A parallel combination of a fuel cell (FC), a photovoltaic (PV) system and a supercapacitor (SC) are used as a hybrid power conversion system (HPCS). The SC compensates for the slow transient response of the FC stack. The HPCS controller comprises a multi-loop voltage controller and a virtual impedance loop for power management. The virtual impedance loop uses a dynamic droop gain to a...

  2. Implementation of hierarchical control in DC microgrids

    Jin, Chi; Wang, Peng; Xiao, Jianfang

    2014-01-01

    of Technology, Singapore. The coordination control among multiple dc sources and energy storages is implemented using a novel hierarchical control technique. The bus voltage essentially acts as an indicator of supply-demand balance. A wireless control is implemented for the reliable operation of the grid....... A reasonable compromise between the maximum power harvest and effective battery management is further enhanced using the coordination control based on a central energy management system. The feasibility and effectiveness of the proposed control strategies have been tested by a dc microgrid in WERL....

  3. Improved microgrid arrangement for integrated imaging polarimeters.

    LeMaster, Daniel A; Hirakawa, Keigo

    2014-04-01

    For almost 20 years, microgrid polarimetric imaging systems have been built using a 2×2 repeating pattern of polarization analyzers. In this Letter, we show that superior spatial resolution is achieved over this 2×2 case when the analyzers are arranged in a 2×4 repeating pattern. This unconventional result, in which a more distributed sampling pattern results in finer spatial resolution, is also achieved without affecting the conditioning of the polarimetric data-reduction matrix. Proof is provided theoretically and through Stokes image reconstruction of synthesized data.

  4. Capacity credit of microgeneration and microgrids

    Moises Costa, Paulo [Escola Superior Tecnologia e Gestao de Viseu, Instituto Politecnico Viseu, Viseu (Portugal); INESC Porto (Portugal); Matos, Manuel A. [INESC Porto, Faculdade de Engenharia, Universidade do Porto, Porto (Portugal)

    2010-10-15

    The recent development of the concept of microgrid ({mu}Grid), associated to the emergent interest in microgeneration ({mu}Gen), has raised a number of challenges regarding the evaluation of the technical, economical and regulatory impacts of a high penetration of this kind of solutions in the power systems. In this paper, the topic of security of supply is addressed, aiming at evaluating the influence of {mu}Gen and {mu}Grids in the medium- and long-term availability of generation to serve the forecasted load. A Monte-Carlo based methodology is used to evaluate this influence and to assess the capacity credit of those entities. (author)

  5. Distributed energy resources in grid interactive AC microgrids

    Wang, Xiongfei; Guerrero, Josep; Chen, Zhe

    2010-01-01

    Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexibility and reliability, becomes an attractive candidate for the configuration...

  6. Evaluation of Reliability Parameters in Micro-grid

    H. Hasanzadeh Fard

    2015-06-01

    Full Text Available Evaluation of the reliability parameters in micro-grids based on renewable energy sources is one of the main problems that are investigated in this paper. Renewable energy sources such as solar and wind energy, battery as an energy storage system and fuel cell as a backup system are used to provide power to the electrical loads of the micro-grid. Loads in the micro-grid consist of interruptible and uninterruptible loads. In addition to the reliability parameters, Forced Outage Rate of each component and also uncertainty of wind power, PV power and demand are considered for micro-grid. In this paper, the problem is formulated as a nonlinear integer minimization problem which minimizes the sum of the total capital, operational, maintenance and replacement cost of DERs. This paper proposes PSO for solving this minimization problem.

  7. Microgrid Policy Review of Selected Major Countries, Regions, and Organizations

    Qu, Min [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Marnay, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-11-30

    This report collects and reviews policies and regulations related to microgrid development, and is intended as a reference. The material is divided into three parts under five dimensions: interconnection, RD&D, tariff policy, other policies, and recommendations.

  8. Distributed cooperative synchronization strategy for multi-bus microgrids

    Sun, Yao; Zhong, Chaolu; Hou, Xiaochao

    2017-01-01

    Microgrids can operate in both grid-connected mode and islanded mode. In order to smooth transfer from islanded mode to grid-connected mode, it is necessary to synchronize the point of common coupling (PCC) with main utility grid (UG) in voltage frequency, phase and amplitude. Conventional...... synchronization methods based on centralized communication are very costly and not suitable for multi-bus microgrids that have a large number of distributed generators (DGs). To address this concern, this study presents an active synchronization control strategy based on distributed cooperation technology...... for multi-bus microgrids. The proposed method can reconnect the microgrid in island to UG seamlessly with sparse communication channels. Synchronization correction signals are generated by a voltage controller, which are only transmitted to the leader DGs. Meanwhile, each DG exchanges information with its...

  9. Dynamic Consensus Algorithm based Distributed Unbalance Compensation in Islanded Microgrids

    Meng, Lexuan; Zhao, Xin; Firoozabadi, Mehdi Savaghebi

    2015-01-01

    In islanded microgrids (MG), distributed generators (DG) can be employed as distributed compensators for improving the power quality (voltage unbalance and harmonics) in consumer side. Hierarchical control is usually applied with different control levels differentiated. In case of voltage unbalance...

  10. Distributed Economic Dispatch in Microgrids Based on Cooperative Reinforcement Learning.

    Liu, Weirong; Zhuang, Peng; Liang, Hao; Peng, Jun; Huang, Zhiwu; Weirong Liu; Peng Zhuang; Hao Liang; Jun Peng; Zhiwu Huang; Liu, Weirong; Liang, Hao; Peng, Jun; Zhuang, Peng; Huang, Zhiwu

    2018-06-01

    Microgrids incorporated with distributed generation (DG) units and energy storage (ES) devices are expected to play more and more important roles in the future power systems. Yet, achieving efficient distributed economic dispatch in microgrids is a challenging issue due to the randomness and nonlinear characteristics of DG units and loads. This paper proposes a cooperative reinforcement learning algorithm for distributed economic dispatch in microgrids. Utilizing the learning algorithm can avoid the difficulty of stochastic modeling and high computational complexity. In the cooperative reinforcement learning algorithm, the function approximation is leveraged to deal with the large and continuous state spaces. And a diffusion strategy is incorporated to coordinate the actions of DG units and ES devices. Based on the proposed algorithm, each node in microgrids only needs to communicate with its local neighbors, without relying on any centralized controllers. Algorithm convergence is analyzed, and simulations based on real-world meteorological and load data are conducted to validate the performance of the proposed algorithm.

  11. Microgrids in Active Network Management-Part I

    Palizban, Omid; Kauhaniemia, Kimmo; Guerrero, Josep M.

    2014-01-01

    The microgrid concept has been closely investigated and implemented by numerous experts worldwide. The first part of this paper describes the principles of microgrid design, considering the operational concepts and requirements arising from participation in active network management. Over the las......, energy storage systems, and market participation in both island and grid-connection operation. Finally, control techniques and the principles of energy-storage systems are summarized in a comprehensive flowchart.......The microgrid concept has been closely investigated and implemented by numerous experts worldwide. The first part of this paper describes the principles of microgrid design, considering the operational concepts and requirements arising from participation in active network management. Over the last...

  12. Distributed Generation Investment by a Microgrid under Uncertainty

    Marnay, Chris; Siddiqui, Afzal; Marnay, Chris

    2008-08-11

    This paper examines a California-based microgrid?s decision to invest in a distributed generation (DG) unit fuelled by natural gas. While the long-term natural gas generation cost is stochastic, we initially assume that the microgrid may purchase electricity at a fixed retail rate from its utility. Using the real options approach, we find a natural gas generation cost threshold that triggers DG investment. Furthermore, the consideration of operational flexibility by the microgrid increases DG investment, while the option to disconnect from the utility is not attractive. By allowing the electricity price to be stochastic, we next determine an investment threshold boundary and find that high electricity price volatility relative to that of natural gas generation cost delays investment while simultaneously increasing the value of the investment. We conclude by using this result to find the implicit option value of the DG unit when two sources of uncertainty exist.

  13. Intelligent Operation and Maintenance of Micro-grid Technology and System Development

    Fu, Ming; Song, Jinyan; Zhao, Jingtao; Du, Jian

    2018-01-01

    In order to achieve the micro-grid operation and management, Studying the micro-grid operation and maintenance knowledge base. Based on the advanced Petri net theory, the fault diagnosis model of micro-grid is established, and the intelligent diagnosis and analysis method of micro-grid fault is put forward. Based on the technology, the functional system and architecture of the intelligent operation and maintenance system of micro-grid are studied, and the microcomputer fault diagnosis function is introduced in detail. Finally, the system is deployed based on the micro-grid of a park, and the micro-grid fault diagnosis and analysis is carried out based on the micro-grid operation. The system operation and maintenance function interface is displayed, which verifies the correctness and reliability of the system.

  14. Dynamic Characteristics Analysis and Stabilization of PV-Based Multiple Microgrid Clusters

    Zhao, Zhuoli; Yang, Ping; Wang, Yuewu

    2018-01-01

    -based multiple microgrid clusters. A detailed small-signal model for PV-based microgrid clusters considering local adaptive dynamic droop control mechanism of the voltage-source PV system is developed. The complete dynamic model is then used to access and compare the dynamic characteristics of the single...... microgrid and interconnected microgrids. In order to enhance system stability of the PV microgrid clusters, a tie-line flow and stabilization strategy is proposed to suppress the introduced interarea and local oscillations. Robustly selecting of the key control parameters is transformed to a multiobjective......As the penetration of PV generation increases, there is a growing operational demand on PV systems to participate in microgrid frequency regulation. It is expected that future distribution systems will consist of multiple microgrid clusters. However, interconnecting PV microgrids may lead to system...

  15. Leveraging Microgrids for Capturing Uncertain Distribution Network Net Load Ramping

    Majzoobi, Alireza; Khodaei, Amin

    2016-01-01

    In this paper, a flexibility-oriented microgrid optimal scheduling model is proposed to mitigate distribution network net load variability caused by large penetration distributed solar generation. The distributed solar generation variability, which is caused by increasing adoption of this technology by end-use consumers, is mainly addressed by electric utilities using grid reinforcement. Microgrids, however, provide viable and local solutions to this pressing challenge. The proposed model, wh...

  16. Protection of Renewable-dominated Microgrids: Challenges and Potential Solutions

    Elkhatib, Mohamed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Biswal, Milan [New Mexico State Univ., Las Cruces, NM (United States); Brahma, Sukumar [New Mexico State Univ., Las Cruces, NM (United States); Ranade, Satish [New Mexico State Univ., Las Cruces, NM (United States)

    2016-11-01

    In this report we address the challenge of designing efficient protection system for inverter- dominated microgrids. These microgrids are characterised with limited fault current capacity as a result of current-limiting protection functions of inverters. Typically, inverters limit their fault contribution in sub-cycle time frame to as low as 1.1 per unit. As a result, overcurrent protection could fail completely to detect faults in inverter-dominated microgrids. As part of this project a detailed literature survey of existing and proposed microgrid protection schemes were conducted. The survey concluded that there is a gap in the available microgrid protection methods. The only credible protection solution available in literature for low- fault inverter-dominated microgrids is the differential protection scheme which represents a robust transmission-grade protection solution but at a very high cost. Two non-overcurrent protection schemes were investigated as part of this project; impedance-based protection and transient-based protection. Impedance-based protection depends on monitoring impedance trajectories at feeder relays to detect faults. Two communication-based impedance-based protection schemes were developed. the first scheme utilizes directional elements and pilot signals to locate the fault. The second scheme depends on a Central Protection Unit that communicates with all feeder relays to locate the fault based on directional flags received from feeder relays. The later approach could potentially be adapted to protect networked microgrids and dynamic topology microgrids. Transient-based protection relies on analyzing high frequency transients to detect and locate faults. This approach is very promising but its implementation in the filed faces several challenges. For example, high frequency transients due to faults can be confused with transients due to other events such as capacitor switching. Additionally, while detecting faults by analyzing transients

  17. MAS-based Distributed Coordinated Control and Optimization in Microgrid and Microgrid Clusters: A Comprehensive Overview

    Han, Yang; Zhang, Ke; Hong, Li

    2018-01-01

    The increasing integration of the distributed renewable energy sources highlights the requirement to design various control strategies for microgrids (MGs) and microgrid clusters (MGCs). The multi-agent system (MAS)-based distributed coordinated control strategies shows the benefits to balance...... the power and energy, stabilize voltage and frequency, achieve economic and coordinated operation among the MGs and MGCs. However, the complex and diverse combinations of distributed generations in multi-agent system increase the complexity of system control and operation. In order to design the optimized...... configuration and control strategy using MAS, the topology models and mathematic models such as the graph topology model, non-cooperative game model, the genetic algorithm and particle swarm optimization algorithm are summarized. The merits and drawbacks of these control methods are compared. Moreover, since...

  18. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    Xiaoling Su

    2015-03-01

    Full Text Available This paper presents a microgrid stability controller (MSC in order to provide existing distributed generation units (DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances. The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing the DGs’ output power. When the microgrid is operating in islanded mode, it provides voltage and frequency support, while guaranteeing seamless transition between the two operation modes. Simulation and experimental results show the effectiveness of the proposed approach.

  19. Adaptive Micro-Grid Operation Based on IEC 61850

    Wei Deng

    2015-05-01

    Full Text Available Automatically identifying the new equipment after its integration and adjusting operation strategy to realize “plug and play” functionality are becoming essential for micro-grid operations. In order to improve and perfect the micro-grid “plug and play” function with the increased amount of equipment with different information protocols and more diverse system applications, this paper presents a solution for adaptive micro-grid operation based on IEC 61850, and proposes the design and specific implementation methods of micro-grid “plug and play” function and system operation mode conversion in detail, by using the established IEC 61850 information model of a micro-grid. Actual operation tests based on the developed IED and micro-grid test platform are performed to verify the feasibility and validity of the proposed solution. The tests results show that the solution can automatically identify the IEC 61850 information model of equipment after its integration, intelligently adjust the operation strategies to adapt to new system states and achieves a reliable system operation mode conversion.

  20. General Dynamic Equivalent Modeling of Microgrid Based on Physical Background

    Changchun Cai

    2015-11-01

    Full Text Available Microgrid is a new power system concept consisting of small-scale distributed energy resources; storage devices and loads. It is necessary to employ a simplified model of microgrid in the simulation of a distribution network integrating large-scale microgrids. Based on the detailed model of the components, an equivalent model of microgrid is proposed in this paper. The equivalent model comprises two parts: namely, equivalent machine component and equivalent static component. Equivalent machine component describes the dynamics of synchronous generator, asynchronous wind turbine and induction motor, equivalent static component describes the dynamics of photovoltaic, storage and static load. The trajectory sensitivities of the equivalent model parameters with respect to the output variables are analyzed. The key parameters that play important roles in the dynamics of the output variables of the equivalent model are identified and included in further parameter estimation. Particle Swarm Optimization (PSO is improved for the parameter estimation of the equivalent model. Simulations are performed in different microgrid operation conditions to evaluate the effectiveness of the equivalent model of microgrid.

  1. Design and Implementation of a Microgrid Energy Management System

    Eun-Kyu Lee

    2016-11-01

    Full Text Available A microgrid is characterized by the integration of distributed energy resources and controllable loads in a power distribution network. Such integration introduces new, unique challenges to microgrid management that have never been exposed to traditional power systems. To accommodate these challenges, it is necessary to redesign a conventional Energy Management System (EMS so that it can cope with intrinsic characteristics of microgrids. While many projects have shown excellent research outcomes, they have either tackled portions of the characteristics or validated their EMSs only via simulations. This paper proposes a Microgrid Platform (MP, an advanced EMS for efficient microgrid operations. We design the MP by taking into consideration (i all the functional requirements of a microgrid EMS (i.e., optimization, forecast, human–machine interface, and data analysis and (ii engineering challenges (i.e., interoperability, extensibility, and flexibility. Moreover, a prototype system is developed and deployed in two smart grid testbeds: UCLA Smart Grid Energy Research Center and Korea Institute of Energy Research. We then conduct experiments to verify the feasibility of the MP design in real-world settings. Our testbeds and experiments demonstrate that the MP is able to communicate with various energy devices and to perform an energy management task efficiently.

  2. Control of Three-Phase Grid-Connected Microgrids Using Artificial Neural Networks

    Shuhui, L.; Fu, X.; Jaithwa, I.; Alonso, E.; Fairbank, M.; Wunsch, D. C.

    2015-01-01

    A microgrid consists of a variety of inverter-interfaced distributed energy resources (DERs). A key issue is how to control DERs within the microgrid and how to connect them to or disconnect them from the microgrid quickly. This paper presents a strategy for controlling inverter-interfaced DERs within a microgrid using an artificial neural network, which implements a dynamic programming algorithm and is trained with a new Levenberg-Marquardt backpropagation algorithm. Compared to conventional...

  3. Selection of a Planning Horizon for a Hybrid Microgrid Using Simulated Wind Forecasts

    2014-12-01

    microgrid robustness and efficiency and may provide operators with real-time guidance and control policies for microgrid operation. ACKNOWLEDGMENTS The...A PLANNING HORIZON FOR A HYBRID MICROGRID USING SIMULATED WIND FORECASTS Mumtaz Karatas Turkish Naval Academy Tuzla, Istanbul, 34942, TURKEY Emily M...Craparo Dashi I. Singham Naval Postgraduate School 1411 Cunningham Road Monterey, CA, 93943 USA ABSTRACT Hybrid microgrids containing renewable energy

  4. Optimal Design and Real Time Implementation of Autonomous Microgrid Including Active Load

    Mohamed A. Hassan; Muhammed Y. Worku; Mohamed A. Abido

    2018-01-01

    Controller gains and power-sharing parameters are the main parameters affect the dynamic performance of the microgrid. Considering an active load to the autonomous microgrid, the stability problem will be more involved. In this paper, the active load effect on microgrid dynamic stability is explored. An autonomous microgrid including three inverter-based distributed generations (DGs) with an active load is modeled and the associated controllers are designed. Controller gains of the inverters ...

  5. Frequency Stability of Hierarchically Controlled Hybrid Photovoltaic-Battery-Hydropower Microgrids

    Guan, Yajuan; Vasquez, Juan Carlos; Guerrero, Josep M.

    2014-01-01

    Hybrid photovolvaic battery-hydropower microgrids can increase electricity accessibility and availability in remote areas. In those microgrids with grid-connected and islanded modes capabilities, seamless transition between both modes is needed as well. However, the different resources with conve......Hybrid photovolvaic battery-hydropower microgrids can increase electricity accessibility and availability in remote areas. In those microgrids with grid-connected and islanded modes capabilities, seamless transition between both modes is needed as well. However, the different resources...

  6. Optimization of an experimental hybrid microgrid operation: reliability and economic issues

    Milo, Aitor; Gaztañaga, Haizea; Etxeberria Otadui, Ion; Bilbao, Endika; Rodríguez Cortés, Pedro

    2009-01-01

    In this paper a hybrid microgrid system, composed of RES (Renewable Energy System) and CHP (Combined Heat and Power) systems together with a battery based storage system is presented. The microgrid is accompanied by a centralized energy management system (CEMS) in order to optimize the microgrid operation both in grid-connected and in stand-alone modes. In grid-connected mode the optimization of the economic exploitation of the microgrid is privileged by applying optim...

  7. Chlamydia trachomatis co-opts GBF1 and CERT to acquire host sphingomyelin for distinct roles during intracellular development.

    Cherilyn A Elwell

    2011-09-01

    Full Text Available The strain designated Chlamydia trachomatis serovar that was used for experiments in this paper is Chlamydia muridarum, a species closely related to C. trachomatis (and formerly termed the Mouse Pneumonitis strain of C. trachomatis. [corrected]. The obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound inclusion that acquires host sphingomyelin (SM, a process that is essential for replication as well as inclusion biogenesis. Previous studies demonstrate that SM is acquired by a Brefeldin A (BFA-sensitive vesicular trafficking pathway, although paradoxically, this pathway is dispensable for bacterial replication. This finding suggests that other lipid transport mechanisms are involved in the acquisition of host SM. In this work, we interrogated the role of specific components of BFA-sensitive and BFA-insensitive lipid trafficking pathways to define their contribution in SM acquisition during infection. We found that C. trachomatis hijacks components of both vesicular and non-vesicular lipid trafficking pathways for SM acquisition but that the SM obtained from these separate pathways is being utilized by the pathogen in different ways. We show that C. trachomatis selectively co-opts only one of the three known BFA targets, GBF1, a regulator of Arf1-dependent vesicular trafficking within the early secretory pathway for vesicle-mediated SM acquisition. The Arf1/GBF1-dependent pathway of SM acquisition is essential for inclusion membrane growth and stability but is not required for bacterial replication. In contrast, we show that C. trachomatis co-opts CERT, a lipid transfer protein that is a key component in non-vesicular ER to trans-Golgi trafficking of ceramide (the precursor for SM, for C. trachomatis replication. We demonstrate that C. trachomatis recruits CERT, its ER binding partner, VAP-A, and SM synthases, SMS1 and SMS2, to the inclusion and propose that these proteins establish an on-site SM biosynthetic

  8. Distributed Storage Inverter and Legacy Generator Integration Plus Renewable Solution for Microgrids

    2015-07-01

    Observation ................. 5 2.1.5 PV Inverter with Microgrid Controls .......................................................... 5 2.2 TECHNOLOGY... CONTROL OF PV POWER RAMP RATE FOR GENERATOR STABILITY ..................... 27 6.11 DEMONSTRATION 11: MICROGRID VOLTAGE SUPPORT FROM PV INVERTER...power delivery optimized storage, transiently rated inverters, integration with legacy generator controls , and microgrid compatible inverters for PV

  9. Distributed Storage Inverter and Legacy Generator Integration Plus Renewables Solution for Microgrids

    2015-07-01

    inverter (advantage of short term storage) and enables microgrid upgrade of legacy generator assets (integration of inverter and generator controllers ...today. The storage inverter controls and hardware are also leveraged to provide an islanding inverter ( microgrid compatibility) for renewable...transiently rated inverters, integration with legacy generator controls , and microgrid compatible inverters for PV. Key system design drivers are lowering

  10. Incorporating Flexibility in the Design of Repairable Systems - Design of Microgrids

    2014-01-01

    MICROGRIDS Vijitashwa Pandey1 Annette Skowronska1,2...optimization of complex systems such as a microgrid is however, computationally intensive. The problem is exacerbated if we must incorporate...flexibility in terms of allowing the microgrid architecture and its running protocol to change with time. To reduce the computational effort, this paper

  11. Symmetrical components and power analysis for a two-phase microgrid system

    Alibeik, M.; Santos Jr., E. C. dos; Blaabjerg, Frede

    2014-01-01

    This paper presents a mathematical model for the symmetrical components and power analysis of a new microgrid system consisting of three wires and two voltages in quadrature, which is designated as a two-phase microgrid. The two-phase microgrid presents the following advantages: 1) constant power...

  12. Source Code Analysis Laboratory (SCALe) for Energy Delivery Systems

    2010-12-01

    technical competence for the type of tests and calibrations SCALe undertakes. Testing and calibration laboratories that comply with ISO / IEC 17025 ...and exec t [ ISO / IEC 2005]. f a software system indicates that the SCALe analysis di by a CERT secure coding standard. Successful conforma antees that...to be more secure than non- systems. However, no study has yet been performed to p t ssment in accordance with ISO / IEC 17000: “a demonstr g to a

  13. Energy management in a microgrid with distributed energy resources

    Zhang, Linfeng; Gari, Nicolae; Hmurcik, Lawrence V.

    2014-01-01

    Highlights: • A performance metric is proposed with the consideration of price, environment effect, and service quality. • Models of a microgrid and a microgrid network are designed with distribute energy resources and storage. • Different cases in MG operation are discussed. - Abstract: A smart grid power system with renewable energy resources and distributed energy storage shows significant improvement in the power system’s emission reduction, reliability, efficiency, and security. A microgrid is a smart grid in a small scale which can be stand-alone or grid-tied. Multi microgrids form a network with energy management and operational planning through two-way power flow and communication. To comprehensively evaluate the performance of a microgrid, a performance metric is proposed with consideration of the electricity price, emission, and service quality, each of them is given a weighting factor. Thus, the performance metric is flexible according to the consumers’ preference. With the weighting factors set in this paper, this performance metric is further applied on microgrids operated as stand-alone, grid-tied, and networked. Each microgrid consists of a solar panel, a hydrogen fuel cell stack, an electrolyzer, a hydrogen storage tank, and a load. For a stand-alone system, the load prediction lowers down the daily electricity consumption about 5.7%, the quantity of H 2 stored fluctuates in a wide range, and overall performance indexes increase with the solar panel size. In a grid-tied MG, the load prediction has a significant effect on the daily consumed electricity which drops 25% in 4 days, some day-time loads are shifted to the night time, and the capacity of hydrogen tank is lower than that in a stand-alone MG. In a network with multiple MGs, the control of the power distribution strongly affects the MG’s performance. However, the overall performance index instead of any specific index increases with the MG’s power generated from renewable energy

  14. Multidimensional optimal droop control for wind resources in DC microgrids

    Bunker, Kaitlyn J.

    Two important and upcoming technologies, microgrids and electricity generation from wind resources, are increasingly being combined. Various control strategies can be implemented, and droop control provides a simple option without requiring communication between microgrid components. Eliminating the single source of potential failure around the communication system is especially important in remote, islanded microgrids, which are considered in this work. However, traditional droop control does not allow the microgrid to utilize much of the power available from the wind. This dissertation presents a novel droop control strategy, which implements a droop surface in higher dimension than the traditional strategy. The droop control relationship then depends on two variables: the dc microgrid bus voltage, and the wind speed at the current time. An approach for optimizing this droop control surface in order to meet a given objective, for example utilizing all of the power available from a wind resource, is proposed and demonstrated. Various cases are used to test the proposed optimal high dimension droop control method, and demonstrate its function. First, the use of linear multidimensional droop control without optimization is demonstrated through simulation. Next, an optimal high dimension droop control surface is implemented with a simple dc microgrid containing two sources and one load. Various cases for changing load and wind speed are investigated using simulation and hardware-in-the-loop techniques. Optimal multidimensional droop control is demonstrated with a wind resource in a full dc microgrid example, containing an energy storage device as well as multiple sources and loads. Finally, the optimal high dimension droop control method is applied with a solar resource, and using a load model developed for a military patrol base application. The operation of the proposed control is again investigated using simulation and hardware-in-the-loop techniques.

  15. Power management of remote microgrids considering battery lifetime

    Chalise, Santosh

    Currently, 20% (1.3 billion) of the world's population still lacks access to electricity and many live in remote areas where connection to the grid is not economical or practical. Remote microgrids could be the solution to the problem because they are designed to provide power for small communities within clearly defined electrical boundaries. Reducing the cost of electricity for remote microgrids can help to increase access to electricity for populations in remote areas and developing countries. The integration of renewable energy and batteries in diesel based microgrids has shown to be effective in reducing fuel consumption. However, the operational cost remains high due to the low lifetime of batteries, which are heavily used to improve the system's efficiency. In microgrid operation, a battery can act as a source to augment the generator or a load to ensure full load operation. In addition, a battery increases the utilization of PV by storing extra energy. However, the battery has a limited energy throughput. Therefore, it is required to provide balance between fuel consumption and battery lifetime throughput in order to lower the cost of operation. This work presents a two-layer power management system for remote microgrids. First layer is day ahead scheduling, where power set points of dispatchable resources were calculated. Second layer is real time dispatch, where schedule set points from the first layer are accepted and resources are dispatched accordingly. A novel scheduling algorithm is proposed for a dispatch layer, which considers the battery lifetime in optimization and is expected to reduce the operational cost of the microgrid. This method is based on a goal programming approach which has the fuel and the battery wear cost as two objectives to achieve. The effectiveness of this method was evaluated through a simulation study of a PV-diesel hybrid microgrid using deterministic and stochastic approach of optimization.

  16. Optimal day-ahead operational planning of microgrids

    Hosseinnezhad, Vahid; Rafiee, Mansour; Ahmadian, Mohammad; Siano, Pierluigi

    2016-01-01

    Highlights: • A new multi-objective model for optimal day-ahead operational planning of microgrids is proposed. • A new concept called seamlessness is introduced to control the sustainability of microgrid. • A new method is developed to manage the load and renewable energy resources estimation errors. • A new solution based on a combination of numerical and evolutionary approaches is proposed. - Abstract: Providing a cost-efficient, eco-friendly and sustainable energy is one of the main issues in modern societies. In response to this demand, new features of microgrid technology have provided huge potentials while distributing electricity more effectively, economically and securely. Accordingly, this paper presents a new multi-objective generation management model for optimal day-ahead operational planning of medium voltage microgrids. The proposed model optimizes both pollutant emission and operating cost of a microgrid by using multi-objective optimization. Besides, a seamlessness-selective algorithm is integrated into the model, which can be adopted to achieve the desired self-sufficiency level for microgrids along a specified planning horizon. Furthermore, the model is characterized by a reserve-assessment strategy developed to handle the load and renewable energy resources estimation errors. The introduced model is solved using a combination of numerical and evolutionary methods of species-based quantum particle swarm optimization to find the optimal scheduling scheme and minos-based optimal power flow to optimize the operating cost and emission. In addition, the suggested solution approach also incorporates an efficient mechanism for considering energy storage systems and coding the candidate solutions in the evolutionary algorithm. The proposed model is implemented on a test microgrid and is investigated through simulations to study the different aspects of the problem. The results show significant improvements and benefits which are obtained by

  17. Distance Protection for Microgrids in Distribution System

    Lin, Hengwei; Liu, Chengxi; Guerrero, Josep M.

    2015-01-01

    protection decreased. This paper adopts distance protection for one mid-voltage level microgrid in Aalborg, Denmark. Different operation modes of the network are analyzed and tested in the paper. The simulation results show that the variations of the fault currents seen by the forward relays are much larger...... than the backward relays. Meanwhile, the fault currents change little with the randomness of renewable energy except the intermittence. Finally, it shows that the designed distance protection has satisfactory performance to clear the various faults.......Owing to the increasing penetration of distributed generation, there are some challenges for the conventional protection in distribution system. Bidirectional power flow and variable fault current because of the various operation modes may lead to the selectivity and sensitivity of the overcurrent...

  18. A Simplified Control Method for Tie-Line Power of DC Micro-Grid

    Yanbo Che; Jinhuan Zhou; Tingjun Lin; Wenxun Li; Jianmei Xu

    2018-01-01

    Compared with the AC micro-grid, the DC micro-grid has low energy loss and no issues of frequency stability, which makes it more accessible for distributed energy. Thus, the DC micro-grid has good potential for development. A variety of renewable energy is included in the DC micro-grid, which is easily affected by the environment, causing fluctuation of the DC voltage. For grid-connected DC micro-grid with droop control strategy, the tie-line power is affected by fluctuations in the DC voltag...

  19. Atmospheric Renewable Energy Research, Volume 3: Solar-Power Microgrids and Atmospheric Influences

    2016-09-01

    1.2 DOD Renewable Energy Applications 1 1.3 Atmospheric Renewable Energy Research Strategy 2 1.4 Microgrid Definitions 3 1.4.1 Mobile Microgrid 4...1.4.2 Hybrid Microgrid 4 1.4.3 Smart Microgrid 4 1.5 Long-Term Atmospheric Renewable Energy Research Vision 5 2. Atmospheric Dependencies 5 2.1...developed-for-Army “ smart ” mobile hybrid microgrid that will incorporate both traditional and renewable energy power resources. A significant

  20. Lessons from international experience for China's microgrid demonstration program

    Romankiewicz, John; Marnay, Chris; Zhou, Nan; Qu, Min

    2014-01-01

    Microgrids can provide an avenue for increasing the amount of distributed generation (DG) and delivery of electricity, where control is more dispersed and quality of service is locally tailored to end-use requirements, with applications from military bases to campuses to commercial office buildings. Many studies have been done to date on microgrid technology and operations, but fewer studies exist on demonstration programs and commercial microgrid development. As China prepares to launch the largest microgrid demonstration program in the world, we review progress made by demonstration programs across Europe, Asia, and the Americas as well as microgrid benefits and barriers. Through case studies, we highlight the difference in experience for microgrids developed under the auspices of a government-sponsored demonstration program versus those that were commercially developed. Lastly, we provide recommendations oriented towards creating a successful microgrid demonstration program. - Highlights: • We discuss major microgrid demonstration programs in the U.S., E.U., and Asia. • We identify barriers faced by microgrids to date and propose policy solutions. • Two detailed case studies of government sponsored microgrid demonstrations are provided. • We outline eight recommendations for microgrid demonstration programs, with a focus on China's upcoming program

  1. Stochastic programming and market equilibrium analysis of microgrids energy management systems

    Hu, Ming-Che; Lu, Su-Ying; Chen, Yen-Haw

    2016-01-01

    Microgrids facilitate optimum utilization of distributed renewable energy, provides better local energy supply, and reduces transmission loss and greenhouse gas emission. Because the uncertainty in energy demand affects the energy demand and supply system, the aim of this research is to develop a stochastic optimization and its market equilibrium for microgrids in the electricity market. Therefore, a two-stage stochastic programming model for microgrids and the market competition model are derived in this paper. In the stochastic model, energy demand and supply uncertainties are considered. Furthermore, a case study of the stochastic model is conducted to simulate the uncertainties on the INER microgrids in Taiwanese market. The optimal investment of the generators and batteries installation and operating strategies are determined under energy demand and supply uncertainties for the INER microgrids. The results show optimal investment and operating strategies for the current INER microgrids are also determined by the proposed two-stage stochastic model in the market. In addition, trade-off between the battery capacity and microgrids performance is investigated. Battery usage and power trading between the microgrids and main grid systems are the functions of battery capacity. - Highlights: • A two-stage stochastic programming model is developed for microgrids. • Market equilibrium analysis of microgrids is conducted. • A case study of the stochastic model is conducted for INER microgrids.

  2. Control of hybrid AC/DC microgrid under islanding operational conditions

    Ding, G.; Gao, F.; Zhang, S.

    2014-01-01

    This paper presents control methods for hybrid AC/DC microgrid under islanding operation condition. The control schemes for AC sub-microgrid and DC sub-microgrid are investigated according to the power sharing requirement and operational reliability. In addition, the key control schemes...... of interlinking converter with DC-link capacitor or energy storage, which will devote to the proper power sharing between AC and DC sub-microgrids to maintain AC and DC side voltage stable, is reviewed. Combining the specific control methods developed for AC and DC sub-microgrids with interlinking converter......, the whole hybrid AC/DC microgrid can manage the power flow transferred between sub-microgrids for improving on the operational quality and efficiency....

  3. Optimal Scheduling of Residential Microgrids Considering Virtual Energy Storage System

    Weiliang Liu

    2018-04-01

    Full Text Available The increasingly complex residential microgrids (r-microgrid consisting of renewable generation, energy storage systems, and residential buildings require a more intelligent scheduling method. Firstly, aiming at the radiant floor heating/cooling system widely utilized in residential buildings, the mathematical relationship between the operative temperature and heating/cooling demand is established based on the equivalent thermodynamic parameters (ETP model, by which the thermal storage capacity is analyzed. Secondly, the radiant floor heating/cooling system is treated as virtual energy storage system (VESS, and an optimization model based on mixed-integer nonlinear programming (MINLP for r-microgrid scheduling is established which takes thermal comfort level and economy as the optimization objectives. Finally, the optimal scheduling results of two typical r-microgrids are analyzed. Case studies demonstrate that the proposed scheduling method can effectively employ the thermal storage capacity of radiant floor heating/cooling system, thus lowering the operating cost of the r-microgrid effectively while ensuring the thermal comfort level of users.

  4. Optimal Bidding Strategy for Renewable Microgrid with Active Network Management

    Seung Wan Kim

    2016-01-01

    Full Text Available Active Network Management (ANM enables a microgrid to optimally dispatch the active/reactive power of its Renewable Distributed Generation (RDG and Battery Energy Storage System (BESS units in real time. Thus, a microgrid with high penetration of RDGs can handle their uncertainties and variabilities to achieve the stable operation using ANM. However, the actual power flow in the line connecting the main grid and microgrid may deviate significantly from the day-ahead bids if the bids are determined without consideration of the real-time adjustment through ANM, which will lead to a substantial imbalance cost. Therefore, this study proposes a formulation for obtaining an optimal bidding which reflects the change of power flow in the connecting line by real-time adjustment using ANM. The proposed formulation maximizes the expected profit of the microgrid considering various network and physical constraints. The effectiveness of the proposed bidding strategy is verified through the simulations with a 33-bus test microgrid. The simulation results show that the proposed bidding strategy improves the expected operating profit by reducing the imbalance cost to a greater degree compared to the basic bidding strategy without consideration of ANM.

  5. SMES application for frequency control during islanded microgrid operation

    Kim, A.-Rong; Kim, Gyeong-Hun; Heo, Serim; Park, Minwon; Yu, In-Keun; Kim, Hak-Man

    2013-01-01

    This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail.

  6. Optimal control in microgrid using multi-agent reinforcement learning.

    Li, Fu-Dong; Wu, Min; He, Yong; Chen, Xin

    2012-11-01

    This paper presents an improved reinforcement learning method to minimize electricity costs on the premise of satisfying the power balance and generation limit of units in a microgrid with grid-connected mode. Firstly, the microgrid control requirements are analyzed and the objective function of optimal control for microgrid is proposed. Then, a state variable "Average Electricity Price Trend" which is used to express the most possible transitions of the system is developed so as to reduce the complexity and randomicity of the microgrid, and a multi-agent architecture including agents, state variables, action variables and reward function is formulated. Furthermore, dynamic hierarchical reinforcement learning, based on change rate of key state variable, is established to carry out optimal policy exploration. The analysis shows that the proposed method is beneficial to handle the problem of "curse of dimensionality" and speed up learning in the unknown large-scale world. Finally, the simulation results under JADE (Java Agent Development Framework) demonstrate the validity of the presented method in optimal control for a microgrid with grid-connected mode. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Elgamal Elliptic Curve Based Secure Communication Architecture for Microgrids

    Sarmadullah Khan

    2018-03-01

    Full Text Available Microgrids play an important role in today’s power systems as the distributed generation is becoming increasingly common. They can operate in two possible modes: (i standalone and (ii grid-connected. The transitional state from standalone to grid-connected mode is very critical and requires the microgrid to be synchronized with the main grid. Thus, secure, reliable and trustworthy control and communication is utmost necessary to prevent out-of-sync connection which could severely damage the microgrid and/or the main grid. Existing solutions consume more resources and take long time to establish a secure connection. The objective of the proposed work is to reduce the connection establishment time by using efficient computational algorithms and save the resources. This paper proposes a secure authentication and key establishment mechanism for ensuring safe operation and control of the microgrids. The proposed approach uses the concept of Elgamal with slight modification. Private key of the sender is used instead of a random number. The proposed modification ensures the non repudiation. This paper also presents a system threat model along with security network architecture and evaluates the performance of proposed algorithm in protecting microgrid communication against man in the middle attacks and replay attacks that could delay the packets to damage the system and need to be detected. Mathematical modeling and simulation results show that the proposed algorithm performs better than the existing protocols in terms of connection establishment, resource consumption and security level.

  8. DC Microgrids Scoping Study. Estimate of Technical and Economic Benefits

    Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Swift, Gregory William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chatzivasileiadis, Spyridon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tschudi, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Glover, Steven [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Starke, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Yue, Meng [Brookhaven National Lab. (BNL), Upton, NY (United States); Hammerstrom, Donald [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-23

    Microgrid demonstrations and deployments are expanding in US power systems and around the world. Although goals are specific to each site, these microgrids have demonstrated the ability to provide higher reliability and higher power quality than utility power systems and improved energy utilization. The vast majority of these microgrids are based on AC power transfer because this has been the traditionally dominant power delivery scheme. Independently, manufacturers, power system designers and researchers are demonstrating and deploying DC power distribution systems for applications where the end-use loads are natively DC, e.g., computers, solid-state lighting, and building networks. These early DC applications may provide higher efficiency, added flexibility, reduced capital costs over their AC counterparts. Further, when onsite renewable generation, electric vehicles and storage systems are present, DC-based microgrids may offer additional benefits. Early successes from these efforts raises a question - can a combination of microgrid concepts and DC distribution systems provide added benefits beyond what has been achieved individually?

  9. Secondary Coordinated Control of Islanded Microgrids Based on Consensus Algorithms

    Wu, Dan; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2014-01-01

    systems. Nevertheless, the conventional decentralized secondary control, although does not need to be implemented in a microgrid central controller (MGCC), it has the limitation that all decentralized controllers must be mutually synchronized. In a clear cut contrast, the proposed secondary control......This paper proposes a decentralized secondary control for islanded microgrids based on consensus algorithms. In a microgrid, the secondary control is implemented in order to eliminate the frequency changes caused by the primary control when coordinating renewable energy sources and energy storage...... requires only a more simplified communication protocol and a sparse communication network. Moreover, the proposed approach based on dynamic consensus algorithms is able to achieve the coordinated secondary performance even when all units are initially out-of-synchronism. The control algorithm implemented...

  10. Secondary Droop for Frequency and Voltage Restoration in Microgrids

    Nutkani, Inam Ullah; Peng, Wang; Blaabjerg, Frede

    2015-01-01

    Droop based autonomous control offers several advantages such as communication independence, plug-n-play capability and enhanced reliability of the system. Despite these advantages, frequency and voltage of droop controlled microgrid varies with the load change which is one of the major drawback...... of the droop control. Presently, the frequency and voltage restoration in microgrid is achieved through secondary control using low bandwidth communication links. This paper presents secondary-droop based frequency and voltage restoration method which is fully autonomous and independent of communication links....... With the proposed method, the microgrid frequency and voltage can be restored back to nominal value without affecting the power sharing performance of the generation sources. The proposed scheme performance has been validated in simulation for several cases of active and reactive power load conditions....

  11. Distributed and decentralized control architectures for converter-interfaced microgrids

    Dragicevic, Tomislav; Wu, Dan; Shafiee, Qobad

    2017-01-01

    This paper gives a summary on recently available technologies for decentralized and distributed control of microgrids. They can be classified into two general categories: 1) power line communication based architectures and 2) multi-agent based architectures. The essential control methods and info......This paper gives a summary on recently available technologies for decentralized and distributed control of microgrids. They can be classified into two general categories: 1) power line communication based architectures and 2) multi-agent based architectures. The essential control methods...... and information sharing algorithms applied in these architectures are reviewed and examined in a hierarchical manner, in order to point out benefits they will bring to future microgrid applications. The paper is concluded with a summary on existing methods and a discussion on future development trends....

  12. Cost-based droop scheme for DC microgrid

    Nutkani, Inam Ullah; Wang, Peng; Loh, Poh Chiang

    2014-01-01

    voltage level, less on optimized operation and control of generation sources. The latter theme is perused in this paper, where cost-based droop scheme is proposed for distributed generators (DGs) in DC microgrids. Unlike traditional proportional power sharing based droop scheme, the proposed scheme......-connected operation. Most importantly, the proposed scheme can reduce overall total generation cost in DC microgrids without centralized controller and communication links. The performance of the proposed scheme has been verified under different load conditions.......DC microgrids are gaining interest due to higher efficiencies of DC distribution compared with AC. The benefits of DC systems have been widely researched for data centers, IT facilities and residential applications. The research focus, however, has been more on system architecture and optimal...

  13. Research and Application of a SCADA System for a Microgrid

    Shuangshuang Li

    2017-03-01

    Full Text Available An effective Supervisory Control and Data Acquisition (SCADA system can improve the reliability, safety and economic benefits of a microgrid operation. In this research, the lower central controller and upper WEB (World Wide Web monitoring system are connected by the SCADA system, which is the hub of a microgrid intelligent monitoring platform. This system contains a set of specific functions programmed by Java as a middleware and can provide communication and control functions between the central controller and the upper monitoring system. For the sake of security and stability of the microgrid, the SCADA system realizes business processing on real-time data acquisition and storage, load balancing and resource recovery, concurrent security processing, and control instruction parsing and transmission. All those functions were tested and verified in actual operation.

  14. Sequential Service Restoration for Unbalanced Distribution Systems and Microgrids

    Chen, Bo; Chen, Chen; Wang, Jianhui; Butler-Purry, Karen L.

    2017-01-01

    The resilience and reliability of modern power systems are threatened by increasingly severe weather events and cyber-physical security events. An effective restoration methodology is desired to optimally integrate emerging smart grid technologies and pave the way for developing self-healing smart grids. In this paper, a sequential service restoration (SSR) framework is proposed to generate restoration solutions for distribution systems and microgrids in the event of large-scale power outages. The restoration solution contains a sequence of control actions that properly coordinate switches, distributed generators, and switchable loads to form multiple isolated microgrids. The SSR can be applied for three-phase unbalanced distribution systems and microgrids and can adapt to various operation conditions. Mathematical models are introduced for three-phase unbalanced power flow, voltage regulators, transformers, and loads. Furthermore, the SSR problem is formulated as a mixed-integer linear programming model, and its effectiveness is evaluated via the modified IEEE 123 node test feeder.

  15. Hierarchical energy management mechanisms for an electricity market with microgrids

    Hong-Tzer Yang

    2014-08-01

    Full Text Available This study addresses a micro-grid electricity market (MGEM with day-ahead (DA and real-time market mechanisms integrated. The bidding mechanisms for the market are described in this study, considering the generation cost of different distributed energy resources (DERs, like distributed generator, energy storage system and demand response. Including load and renewable generation forecasting systems and a fuzzy decision supporting system, a hierarchical micro-grid energy management system (MG-EMS is then proposed to ensure the benefits of involved micro-grid central controller, DER owners and customers. To verify the feasibility of the proposed system, the whole-year historical pricing and load data for New England independent system operator are employed. The numerical results show that the proposed MG-EMS is promising and effective for the operations of MGEM.

  16. A Novel Unscheduled Islanding Detection Method for Microgrid

    Li Hui

    2018-01-01

    Full Text Available Microgrid with its intelligent and flexible control characteristics conform to the trend of sustainable development of electricity, and when the microgrid in the unplanned island state, the successful detection of the island is a prerequisite, energy storage inverter as the key equipment in the microgrid system, island protection is one of the necessary functions. In this paper, an improved islanding detection method based on active frequency drift and q-axis reactive power perturbation is proposed. The method has the advantages of faster detection speed and minor influence on power quality, which makes the energy storage inverter with better output power quality when it works on grid-connected state, and can be detected the islanding state quickly from grid-connected mode to islanded mode. Finally, the validity and superiority of the improved island detection method are verified by simulation experiments.

  17. Distributed Cooperative Secondary Control of Microgrids Using Feedback Linearization

    Bidram, Ali; Davoudi, Ali; Lewis, Frank

    2013-01-01

    This paper proposes a secondary voltage control of microgrids based on the distributed cooperative control of multi-agent systems. The proposed secondary control is fully distributed; each distributed generator (DG) only requires its own information and the information of some neighbors. The dist......This paper proposes a secondary voltage control of microgrids based on the distributed cooperative control of multi-agent systems. The proposed secondary control is fully distributed; each distributed generator (DG) only requires its own information and the information of some neighbors...... parameters can be tuned to obtain a desired response speed. The effectiveness of the proposed control methodology is verified by the simulation of a microgrid test system....

  18. Economic Droop Scheme for Decentralized Power Management in DC Microgrids

    E. Alizadeh

    2016-12-01

    Full Text Available This paper proposes an autonomous and economic droop control scheme for DC microgrid application. In this method, a cost-effective power sharing technique among various types of DG units is properly adopted. The droop settings are determined based on an algorithm to individually manage the power management without any complicated optimization methods commonly applied in the centralized control method. In the proposed scheme, the system retains all the advantages of the traditional droop method while minimizes the generation costs of the DC microgrid. In the proposed method, all DGs are classified in a sorting rule based on their total generation cost and the reference voltage of their droop equations is then determined. The proposed scheme is applied to a typical DC microgrid consisting of four different types of DGs and a controllable load. The simulation results are presented to verify the effectiveness of the proposed method using MATLAB/SIMULINK software.

  19. Distributed generation investment by a microgrid under uncertainty

    Siddiqui, Afzal S.; Marnay, Chris

    2008-01-01

    This paper examines a California-based microgrid's decision to invest in a distributed generation (DG) unit fuelled by natural gas. While the long-term natural gas generation cost is stochastic, we initially assume that the microgrid may purchase electricity at a fixed retail rate from its utility. Using the real options approach, we find a natural gas generation cost threshold that triggers DG investment. Furthermore, the consideration of operational flexibility by the microgrid increases DG investment, while the option to disconnect from the utility is not attractive. By allowing the electricity price to be stochastic, we next determine an investment threshold boundary and find that high electricity price volatility relative to that of natural gas generation cost delays investment while simultaneously increasing the value of the investment. We conclude by using this result to find the implicit option value of the DG unit when two sources of uncertainty exist. (author)

  20. Distributed generation investment by a microgrid under uncertainty

    Siddiqui, Afzal S. [Department of Statistical Science, University College London, Gower Street, London WC1E 6BT (United Kingdom); Marnay, Chris [Ernest Orlando Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS90R4000, Berkeley, CA 94720-8163 (United States)

    2008-12-15

    This paper examines a California-based microgrid's decision to invest in a distributed generation (DG) unit fuelled by natural gas. While the long-term natural gas generation cost is stochastic, we initially assume that the microgrid may purchase electricity at a fixed retail rate from its utility. Using the real options approach, we find a natural gas generation cost threshold that triggers DG investment. Furthermore, the consideration of operational flexibility by the microgrid increases DG investment, while the option to disconnect from the utility is not attractive. By allowing the electricity price to be stochastic, we next determine an investment threshold boundary and find that high electricity price volatility relative to that of natural gas generation cost delays investment while simultaneously increasing the value of the investment. We conclude by using this result to find the implicit option value of the DG unit when two sources of uncertainty exist. (author)

  1. Modelling and simulation of microgrid application at RCET

    Jabbar, R.A.; Junaid, M.; Ashraf, M; Ullah, I. [Rachna College of Engineering and Technology, Gujranwala (Pakistan); Mohammed, Z. [Kebangsaan Malaysia Univ., Selangor (Malaysia)

    2009-03-11

    Pakistan's energy crisis is causing electricity shortages and blackouts in the country. This paper presented details of microgrid concept that used locally available renewable energy resources located within the Gujranwala region of Pakistan. The renewable energy sources were integrated to function as a single generating unit for the microgrid. The study considered 3 different energy sources, notably (1) biomass and hydrogen fuel cells, and (2) a photovoltaic (PV) array, and (3) a micro-hydro facility. A simulation of the microgrid concept was conducted using a commercial simulation tool. A comparison of different motor and generator set techniques was also presented. The aim of the study was to ensure a standby power supply source for the Rachna College of Engineering and Technology (RCET) library during electricity outages. The approach can be used to help electric power regulatory authorities to minimize gaps between supply and demand. 15 refs., 4 tabs., 20 figs.

  2. Microgrid Controllers : Expanding Their Role and Evaluating Their Performance

    Maitra, Arindam; Pratt, Annabelle; Hubert, Tanguy; Wang, Dean; Prabakar, Kumaraguru; Handa, Rachna; Baggu, Murali; McGranaghan, Mark

    2017-07-01

    Microgrids have long been deployed to provide power to customers in remote areas as well as critical industrial and military loads. Today, they are also being proposed as grid-interactive solutions for energy-resilient communities. Such microgrids will spend most of the time operating while synchronized with the surrounding utility grid but will also be capable of separating during contingency periods due to storms or temporary disturbances such as local grid faults. Properly designed and grid-integrated microgrids can provide the flexibility, reliability, and resiliency needs of both the future grid and critical customers. These systems can be an integral part of future power system designs that optimize investments to achieve operational goals, improved reliability, and diversification of energy sources.

  3. SMES application for frequency control during islanded microgrid operation

    Kim, A-Rong; Kim, Gyeong-Hun; Heo, Serim; Park, Minwon; Yu, In-Keun; Kim, Hak-Man

    2013-01-01

    Highlights: ► The operating characteristics of SMES for the frequency control of an islanded microgrid were investigated. ► The SMES contributes well for frequency control in the islanded operation. ► A dual and a single magnet type of SMES have been compared to demonstrate the performances. -- Abstract: This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail

  4. SMES application for frequency control during islanded microgrid operation

    Kim, A-Rong, E-mail: haven21c@changwon.ac.kr [Changwon National University, Sarim-dong, Changwon 641-773 (Korea, Republic of); Kim, Gyeong-Hun; Heo, Serim; Park, Minwon [Changwon National University, Sarim-dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@changwon.ac.kr [Changwon National University, Sarim-dong, Changwon 641-773 (Korea, Republic of); Kim, Hak-Man [University of Incheon, Songdo-dong, Incheon 406-772 (Korea, Republic of)

    2013-01-15

    Highlights: ► The operating characteristics of SMES for the frequency control of an islanded microgrid were investigated. ► The SMES contributes well for frequency control in the islanded operation. ► A dual and a single magnet type of SMES have been compared to demonstrate the performances. -- Abstract: This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail.

  5. Real-time management solutions for a smart polygeneration microgrid

    Rossi, Iacopo; Banta, Larry; Cuneo, Alessandra; Ferrari, Mario Luigi; Traverso, Alberto Nicola; Traverso, Alberto

    2016-01-01

    Highlights: • Different management systems are compared on the basis of experimental results. • Target system is a real smart microgrid composed by different co-generative systems. • A complex demand scenario was used to test decision-making of the controllers. • Experimental results were analyzed from both economic and reliability viewpoints. - Abstract: In recent years, many different concepts to manage smart distributed systems were proposed and solutions developed. Smart grids and the increasing influence of renewable sources on energy production lead to concerns about grid stability and load balance. Combined Heat and Power (CHP) generators coupled with solar or other renewable sources offer the opportunity to satisfy both electric and thermal power economically. Both electric and thermal demand and supply change continuously, and sources such as solar and wind are not dispatchable or accurately predictable. At the same time, it is essential to use the most efficient and cost effective sources to satisfy the demand. This problem has been studied at the University of Genoa (UNIGE), Italy, using different generators and energy storage device that can supply both electric and thermal energy to consumer buildings. Here the problem is formulated as a constrained Multi-Input Multi-Output (MIMO) problem with sometimes conflicting requests that must be satisfied. The results come from experiments carried out on the test rig located at the Innovative Energy System Laboratories (IESL) of the Thermochemical Power Group (TPG) of UNIGE. This paper compares three different control approaches to manage the distributed generation system: Simplified Management Control (SMC), Model Predictive Control (MPC), and Multi-Commodity Matcher (MCM). Control systems and their control actions are evaluated through economic and performance key indicators.

  6. A knowledge discovery in databases approach for industrial microgrid planning

    Gamarra, Carlos; Guerrero, Josep M.; Montero, Eduardo

    2016-01-01

    The progressive application of Information and Communication Technologies to industrial processes has increased the amount of data gathered by manufacturing companies during last decades. Nowadays some standardized management systems, such as ISO 50.001 and ISO 14.001, exploit these data in order...... sustainable and proactive microgrid which allows identifying, designing and developing energy efficiency strategies at supply, management and energy use levels. In this context, the expansion of Internet of Things and Knowledge Discovery in Databases techniques will drive changes in current microgrid planning...

  7. Adaptive Overcurrent Protection for Microgrids in Extensive Distribution Systems

    Lin, Hengwei; Guerrero, Josep M.; Jia, Chenxi

    2016-01-01

    Microgrid is regarded as a new form to integrate the increasing penetration of distributed generation units (DGs) in the extensive distribution systems. This paper proposes an adaptive overcurrent protection strategy for a microgrid network. The protection coordination of the overcurrent relays...... measurements in another neural network model. Reconfigurations can be performed to modify the settings of the on-field relays to enhance the reliable operation for the different operational situations. The test results show that the adaptive overcurrent protection scheme with the assistance of estimation model...... can modify the protective settings for the new operation state accurately and intelligently....

  8. MAS Based Event-Triggered Hybrid Control for Smart Microgrids

    Dou, Chunxia; Liu, Bin; Guerrero, Josep M.

    2013-01-01

    This paper is focused on an advanced control for autonomous microgrids. In order to improve the performance regarding security and stability, a hierarchical decentralized coordinated control scheme is proposed based on multi-agents structure. Moreover, corresponding to the multi-mode and the hybrid...... haracteristics of microgrids, an event-triggered hybrid control, including three kinds of switching controls, is designed to intelligently reconstruct operation mode when the security stability assessment indexes or the constraint conditions are violated. The validity of proposed control scheme is demonstrated...

  9. Efficient Energy Management for a Grid-Tied Residential Microgrid

    Anvari-Moghaddam, Amjad; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    In this paper, an effective energy management system (EMS) for application in integrated building and microgrid system is introduced and implemented as a multi-objective optimization problem. The proposed architecture covers different key modelling aspects such as distributed heat and electricity......’s objectives, the effectiveness and applicability of the proposed model is studied and validated compared to the existing residential EMSs. The simulation results demonstrate that the proposed EMS has the capability not only to conserve energy in sustainable homes and microgrid system and to reduce energy...

  10. Hierarchical Control for Multiple DC-Microgrids Clusters

    Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2014-01-01

    DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed in this p......DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed...

  11. Multi-Functional Distributed Secondary Control for Autonomous Microgrids

    Shafiee, Qobad

    Microgrids (MGs)--the building blocks of the smart grid-- are local grids comprise different technologies such as power electronics converters, distributed renewable and non-renewable energy sources, energy storage systems, and telecommunications which can operate either in islanded mode or conne......Microgrids (MGs)--the building blocks of the smart grid-- are local grids comprise different technologies such as power electronics converters, distributed renewable and non-renewable energy sources, energy storage systems, and telecommunications which can operate either in islanded mode...

  12. Secondary Control for Voltage Quality Enhancement in Microgrids

    Savaghebi, Mehdi; Jalilian, Alireza; Vasquez, Juan Carlos

    2012-01-01

    In this paper, a hierarchical control scheme is proposed for enhancement of sensitive load bus (SLB) voltage quality in microgrids. The control structure consists of primary and secondary levels. The primary control level comprises distributed generators (DGs) local controllers. Each of these con......In this paper, a hierarchical control scheme is proposed for enhancement of sensitive load bus (SLB) voltage quality in microgrids. The control structure consists of primary and secondary levels. The primary control level comprises distributed generators (DGs) local controllers. Each...

  13. Distributed maximum power point tracking in wind micro-grids

    Carlos Andrés Ramos-Paja

    2012-06-01

    Full Text Available With the aim of reducing the hardware requirements in micro-grids based on wind generators, a distributed maximum power point tracking algorithm is proposed. Such a solution reduces the amount of current sensors and processing devices to maximize the power extracted from the micro-grid, reducing the application cost. The analysis of the optimal operating points of the wind generator was performed experimentally, which in addition provides realistic model parameters. Finally, the proposed solution was validated by means of detailed simulations performed in the power electronics software PSIM, contrasting the achieved performance with traditional solutions.

  14. Droop-free Distributed Control for AC Microgrids

    Nasirian, Vahidreza; Shafiee, Qobad; Guerrero, Josep M.

    2016-01-01

    A cooperative distributed secondary/primary control paradigm for AC microgrids is proposed. This solution replaces the centralized secondary control and the primary-level droop mechanism of each inverter with three separate regulators: voltage, reactive power, and active power regulators. A sparse...... guidelines are provided. Steady-state performance analysis shows that the proposed controller can accurately handle the global voltage regulation and proportional load sharing. An AC microgrid prototype is set up, where the controller performance, plug-and-play capability, and resiliency to the failure...

  15. Online algorithms for optimal energy distribution in microgrids

    Wang, Yu; Nelms, R Mark

    2015-01-01

    Presenting an optimal energy distribution strategy for microgrids in a smart grid environment, and featuring a detailed analysis of the mathematical techniques of convex optimization and online algorithms, this book provides readers with essential content on how to achieve multi-objective optimization that takes into consideration power subscribers, energy providers and grid smoothing in microgrids. Featuring detailed theoretical proofs and simulation results that demonstrate and evaluate the correctness and effectiveness of the algorithm, this text explains step-by-step how the problem can b

  16. Consensus based scheduling of storage capacities in a virtual microgrid

    Brehm, Robert; Top, Søren; Mátéfi-Tempfli, Stefan

    2017-01-01

    We present a distributed, decentralized method for coordinated scheduling of charge/discharge intervals of storage capacities in a utility grid integrated microgrid. The decentralized algorithm is based on a consensus scheme and solves an optimisation problem with the objective of minimising......, by use of storage capacities, the power flow over a transformer substation from/to the utility grid integrated microgrid. It is shown that when using this coordinated scheduling algorithm, load profile flattening (peak-shaving) for the utility grid is achieved. Additionally, mutual charge...

  17. Hybrid Microgrid Configuration Optimization with Evolutionary Algorithms

    Lopez, Nicolas

    This dissertation explores the Renewable Energy Integration Problem, and proposes a Genetic Algorithm embedded with a Monte Carlo simulation to solve large instances of the problem that are impractical to solve via full enumeration. The Renewable Energy Integration Problem is defined as finding the optimum set of components to supply the electric demand to a hybrid microgrid. The components considered are solar panels, wind turbines, diesel generators, electric batteries, connections to the power grid and converters, which can be inverters and/or rectifiers. The methodology developed is explained as well as the combinatorial formulation. In addition, 2 case studies of a single objective optimization version of the problem are presented, in order to minimize cost and to minimize global warming potential (GWP) followed by a multi-objective implementation of the offered methodology, by utilizing a non-sorting Genetic Algorithm embedded with a monte Carlo Simulation. The method is validated by solving a small instance of the problem with known solution via a full enumeration algorithm developed by NREL in their software HOMER. The dissertation concludes that the evolutionary algorithms embedded with Monte Carlo simulation namely modified Genetic Algorithms are an efficient form of solving the problem, by finding approximate solutions in the case of single objective optimization, and by approximating the true Pareto front in the case of multiple objective optimization of the Renewable Energy Integration Problem.

  18. Selective virtual capacitive impedance loop for harmonics voltage compensation in islanded microgrids

    Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril

    2013-01-01

    Parallel inverters having LCL output filters cause voltage distortions at the point of common coupling (PCC) in islanded microgrids when non-linear loads are present. A capacitive virtual impedance loop could be used to provide selective harmonic compensation in islanded microgrids, instead of in...... resistance for selective harmonic compensation in islanded microgrids. Simulation results were given to show the suitability of the proposed algorithms in reducing the voltage harmonics at the PCC.......Parallel inverters having LCL output filters cause voltage distortions at the point of common coupling (PCC) in islanded microgrids when non-linear loads are present. A capacitive virtual impedance loop could be used to provide selective harmonic compensation in islanded microgrids, instead...... of introducing additional active or passive filters into the system that could compromise the stability of the microgrid. However, the performance of these compensation loops becomes degraded when a virtual resistance is introduced with the aim to improve the overall stability of the parallel inverters...

  19. An improved power control strategy for hybrid AC-DC microgrids

    Baharizadeh, Mehdi; Karshenas, Hamid Reza; Guerrero, Josep M.

    2018-01-01

    This paper presents a new droop-based control strategy for hybrid microgrids (HMG) with improved power sharing. When ac microgrids (AC-MG) and dc microgrids (DC-MG) are present in a distribution grid, there is an opportunity to interconnect them via an interlinking converter (IC) and form a HMG......, the possibility of participation of IC in AC-MG reactive power adds some complexity to a HMG control system. In this paper, a new decentralized control strategy is presented for a HMG which relies on regulating the voltage magnitude of a common bus in each microgrid. In this regard, new droop characteristics...... for sources across both microgrids as well as IC are proposed. The proposed droop characteristics result in better active/reactive power sharing across both microgrids and at the same time results in better voltage regulation. The derivation of new droop characteristics is thoroughly discussed in this paper...

  20. Power coordinated control method with frequency support capability for hybrid single/three-phase microgrid

    Zhou, Xiaoping; Chen, Yandong; Zhou, Leming

    2018-01-01

    storage unit (ESU) are added into hybrid single/three-phase microgrid, and a power coordinated control method with frequency support capability is proposed for hybrid single/three-phase microgrid in this study. PEU is connected with three single-phase microgrids to coordinate power exchange among three...... phases and provide frequency support for hybrid microgrid. Meanwhile, a power coordinated control method based on the droop control is proposed for PEU to alleviate three-phase power imbalance and reduce voltage fluctuation of hybrid microgrid. Besides, ESU is injected into the DC-link to buffer......Due to the intermittent output power of distributed generations (DGs) and the variability of loads, voltage fluctuation and three-phase power imbalance easily occur when hybrid single/three-phase microgrid operates in islanded mode. To address these issues, the power exchange unit (PEU) and energy...

  1. Multilayer PV-storage Microgrids Algorithm for the Dispatch of Distributed Network

    Yang Ping

    2016-01-01

    Full Text Available In recent years, due to the support of our country, PV-storage microgrid develops rapidly. However, the flexible network operation modes of PV-storage microgrid change flexibly and the operating characteristics with a large amout of sources is highly complicated. Based on the existing microgrid coordinate control methods, this paper proposes multilayer PV-storage microgrid algorithm for fitting dispatch of distributed network, which achieves maximum output of renewable energy when meeting the scheduling requirements of network, by building PV-storage microgrid type dynamic simulation system in a variety of conditions in PSCAD. Simulation results show that the heuristic algorithm proposed can achieve microgrid stable operation and satisfy the demands of the dispatch in distributed network.

  2. Selective compensation of voltage harmonics in grid-connected microgrids

    Savaghebi, Mehdi; Vasquez, Juan Carlos; Jalilian, Alireza

    2013-01-01

    In this paper, a novel approach is proposed for selective compensation of main voltage harmonics in a grid-connected microgrid. The aim of compensation is to provide a high voltage quality at the point of common coupling (PCC). PCC voltage quality is of great importance due to sensitive loads tha...... to an acceptable level....

  3. Secondary Voltage Control for Harmonics Suppression in Islanded Microgrids

    Wang, Xiongfei; Guerrero, Josep M.; Blaabjerg, Frede

    2011-01-01

    in islanded microgrids. In addition to the centralized controller for fundamental frequency voltage component, a selective harmonic compensator is implemented in the secondary voltage control system. With the help of Park transformation, the cyclic references generated by the selective harmonic compensator...

  4. Power Talk for Multibus DC MicroGrids

    Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

    2016-01-01

    We study a communication framework for nonlinear multibus DC MicroGrids based on a deliberate modification of the parameters of the primary control and termed power talk. We assess the case in which the information is modulated in the deviations of reference voltages of the primary control loops...

  5. High Penetration of Electrical Vehicles in Microgrids: Threats and Opportunities

    Khederzadeh, Mojtaba; Khalili, Mohammad

    2014-10-01

    Given that the microgrid concept is the building block of future electric distribution systems and electrical vehicles (EVs) are the future of transportation market, in this paper, the impact of EVs on the performance of microgrids is investigated. Demand-side participation is used to cope with increasing demand for EV charging. The problem of coordination of EV charging and discharging (with vehicle-to-grid (V2G) functionality) and demand response is formulated as a market-clearing mechanism that accepts bids from the demand and supply sides and takes into account the constraints put forward by different parts. Therefore, a day-ahead market with detailed bids and offers within the microgrid is designed whose objective is to maximize the social welfare which is the difference between the value that consumers attach to the electrical energy they buy plus the benefit of the EV owners participating in the V2G functionality and the cost of producing/purchasing this energy. As the optimization problem is a mixed integer nonlinear programming one, it is decomposed into one master problem for energy scheduling and one subproblem for power flow computation. The two problems are solved iteratively by interfacing MATLAB with GAMS. Simulation results on a sample microgrid with different residential, commercial and industrial consumers with associated demand-side biddings and different penetration level of EVs support the proposed formulation of the problem and the applied methods.

  6. Microgrids in Active Network Management-Part II

    Palizban, Omid; Kauhaniemi, Kimmo; Guerrero, Josep M.

    2014-01-01

    , following planned or unplanned transitions to island mode, microgrids may develop instability. For this reason, the paper addresses the principles behind island-detection methods, black-start operation, fault management, and protection systems, along with a comprehensive review of power quality. Finally...

  7. Modular Energy Management System Applicable to Residential Microgrids

    Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Graells, Moises

    2016-01-01

    In this paper, an energy management system is defined as a flexible architecture. This proposal can be applied to home and residential areas when they include generation units. The system has been integrated and tested in a grid-connected microgrid prototype, where optimal power generation profiles...

  8. Microgrids, virtual power plants and our distributed energy future

    Asmus, Peter

    2010-12-15

    Opportunities for VPPs and microgrids will only increase dramatically with time, as the traditional system of building larger and larger centralized and polluting power plants by utilities charging a regulated rate of return fades. The key questions are: how soon will these new business models thrive - and who will be in the driver's seat? (author)

  9. Autonomous Active and Reactive Power Distribution Strategy in Islanded Microgrids

    Wu, Dan; Tang, Fen; Guerrero, Josep M.

    2014-01-01

    This paper proposes an autonomous active and reactive power distribution strategy that can be applied directly on current control mode (CCM) inverters, being compatible as well with conventional droop-controlled voltage control mode (VCM) converters. In a microgrid, since renewable energy sources...

  10. Virtual Admittance Loop for Voltage Harmonic Compensation in Microgrids

    Blanco, Cristian; Reigosa, David; Quintero, Juan Carlos Vasquez

    2016-01-01

    The use of the virtual admittance concept for harmonic and/or unbalance compensation in microgrids when multiple inverters operate in parallel is proposed in this paper. The virtual impedance concept has been traditionally used for these purposes. However, one drawback of the virtual impedance...

  11. Distributed coordination of energy-storage capacities in virtual microgrids

    Brehm, Robert; Ramezani, Hossein; Jouffroy, Jerome

    cooperation is incorported, storage capacities can be operated as a virtual microgrid. The cooperation between nodes is based on the formulation of a simple objective function for coordination. The cooperation objective is then combined with each node’s local objective, which is the increase of self...

  12. A Direct Voltage Unbalance Compensation Strategy for Islanded Microgrids

    Zhao, Xin; Wu, Xiaohua; Meng, Lexuan

    2015-01-01

    and nonlinear loads. Moreover, by adjusting voltage references according to the amplitude of the negative sequence voltage, the unbalance factor, which is mainly caused by single phase generators/loads, can be mitigated to an extremely low value. Finally, an AC microgrid which includes three three-phase three...

  13. Microgrids Real-Time Pricing Based on Clustering Techniques

    Hao Liu

    2018-05-01

    Full Text Available Microgrids are widely spreading in electricity markets worldwide. Besides the security and reliability concerns for these microgrids, their operators need to address consumers’ pricing. Considering the growth of smart grids and smart meter facilities, it is expected that microgrids will have some level of flexibility to determine real-time pricing for at least some consumers. As such, the key challenge is finding an optimal pricing model for consumers. This paper, accordingly, proposes a new pricing scheme in which microgrids are able to deploy clustering techniques in order to understand their consumers’ load profiles and then assign real-time prices based on their load profile patterns. An improved weighted fuzzy average k-means is proposed to cluster load curve of consumers in an optimal number of clusters, through which the load profile of each cluster is determined. Having obtained the load profile of each cluster, real-time prices are given to each cluster, which is the best price given to all consumers in that cluster.

  14. A Novel Distributed Secondary Coordination Control Approach for Islanded Microgrids

    Lu, Xiaoqing; Yu, Xinghuo; Lai, Jingang

    2018-01-01

    This paper develops a new distributed secondary cooperative control scheme to coordinate distributed generators (DGs) in islanded microgrids (MGs). A finite time frequency regulation strategy containing a consensus-based distributed active power regulator is presented, which can not only guarantee...

  15. Virtual admittance loop for voltage harmonic compensation in microgrids

    Blanco, Cristian; Reigosa, David; Quintero, Juan Carlos Vasquez

    2015-01-01

    The use of the virtual admittance concept for harmonic and/or unbalance compensation in microgrids when multiple inverters operate in parallel is proposed in this paper. The virtual impedance concept has been traditionally used for these purposes. However, one drawback of the virtual impedance...

  16. Equivalence of Primary Control Strategies for AC and DC Microgrids

    Eneko Unamuno

    2017-01-01

    Full Text Available Microgrid frequency and voltage regulation is a challenging task, as classical generators with rotational inertia are usually replaced by converter-interfaced systems that inherently do not provide any inertial response. The aim of this paper is to analyse and compare autonomous primary control techniques for alternating current (AC and direct current (DC microgrids that improve this transient behaviour. In this context, a virtual synchronous machine (VSM technique is investigated for AC microgrids, and its behaviour for different values of emulated inertia and droop slopes is tested. Regarding DC microgrids, a virtual-impedance-based algorithm inspired by the operation concept of VSMs is proposed. The results demonstrate that the proposed strategy can be configured to have an analogous behaviour to VSM techniques by varying the control parameters of the integrated virtual-impedances. This means that the steady-state and transient behaviour of converters employing these strategies can be configured independently. As shown in the simulations, this is an interesting feature that could be, for instance, employed for the integration of different dynamic generation or storage systems, such as batteries or supercapacitors.

  17. A robust adaptive load frequency control for micro-grids

    Khooban, Mohammad Hassan; Niknam, Taher; Blaabjerg, Frede

    2016-01-01

    micro-grid (MG) is introduced that can consider electric vehicles׳ (EV(s)) effect. Moreover, in this paper, a new combination of the General Type II Fuzzy Logic Sets (GT2FLS) and the Modified Harmony Search Algorithm (MHSA) technique is applied for adaptive tuning of proportional-integral (PI...

  18. Adaptive suboptimal second-order sliding mode control for microgrids

    Incremona, Gian Paolo; Cucuzzella, Michele; Ferrara, Antonella

    2016-09-01

    This paper deals with the design of adaptive suboptimal second-order sliding mode (ASSOSM) control laws for grid-connected microgrids. Due to the presence of the inverter, of unpredicted load changes, of switching among different renewable energy sources, and of electrical parameters variations, the microgrid model is usually affected by uncertain terms which are bounded, but with unknown upper bounds. To theoretically frame the control problem, the class of second-order systems in Brunovsky canonical form, characterised by the presence of matched uncertain terms with unknown bounds, is first considered. Four adaptive strategies are designed, analysed and compared to select the most effective ones to be applied to the microgrid case study. In the first two strategies, the control amplitude is continuously adjusted, so as to arrive at dominating the effect of the uncertainty on the controlled system. When a suitable control amplitude is attained, the origin of the state space of the auxiliary system becomes attractive. In the other two strategies, a suitable blend between two components, one mainly working during the reaching phase, the other being the predominant one in a vicinity of the sliding manifold, is generated, so as to reduce the control amplitude in steady state. The microgrid system in a grid-connected operation mode, controlled via the selected ASSOSM control strategies, exhibits appreciable stability properties, as proved theoretically and shown in simulation.

  19. Adaptive control for solar energy based DC microgrid system development

    Zhang, Qinhao

    During the upgrading of current electric power grid, it is expected to develop smarter, more robust and more reliable power systems integrated with distributed generations. To realize these objectives, traditional control techniques are no longer effective in either stabilizing systems or delivering optimal and robust performances. Therefore, development of advanced control methods has received increasing attention in power engineering. This work addresses two specific problems in the control of solar panel based microgrid systems. First, a new control scheme is proposed for the microgrid systems to achieve optimal energy conversion ratio in the solar panels. The control system can optimize the efficiency of the maximum power point tracking (MPPT) algorithm by implementing two layers of adaptive control. Such a hierarchical control architecture has greatly improved the system performance, which is validated through both mathematical analysis and computer simulation. Second, in the development of the microgrid transmission system, the issues related to the tele-communication delay and constant power load (CPL)'s negative incremental impedance are investigated. A reference model based method is proposed for pole and zero placements that address the challenges of the time delay and CPL in closed-loop control. The effectiveness of the proposed modeling and control design methods are demonstrated in a simulation testbed. Practical aspects of the proposed methods for general microgrid systems are also discussed.

  20. A novel intelligent control of HVAC system in smart microgrid

    Seyed Mehdi Hakimi

    2017-09-01

    Full Text Available Heating systems have played an important role in building energy and comfort management. This paper set forth a novel intelligent residential heating system controller that has smart grid functionality. In smart grid, demand response systems now have the ability to not only engage commercial and industrial customers, but also the individual residential customers. Additionally, the ability exists to have automated control systems which operate on an availability of renewable energy and welfare of customers. In this paper one possible implementation of an active controller will be examined. An active controller operates by responding to a combination of internal set points and external signal from local control entity. The optimization objective of the heating systems management was to minimize the cost of smart microgrid, minimize the size of smart microgrid units, minimize import energy from distribution grid and maximize reliability of smart microgrid. This means that, smart heating system and renewable energy can work well together and their individual benefits can be added together when used in combination. Simulation studies are used to demonstrate the capability on the proposed heating system controller on the planning of a smart microgrid system.

  1. Improved Control Strategy for Microgrid Ultracapacitor Energy Storage Systems

    Xiaobo Dou

    2014-12-01

    Full Text Available Ultracapacitors (UCs, with their features of high power density and high current charge-discharge, have become the best choice for dynamic power compensation to improve the stability of microgrids and are increasingly being applied in microgrids. This paper presents the control of an energy storage system (ESS based on ultracapacitors in the context of grid-connected microgrids. The ESS is composed of DC/AC and DC/DC converters tied by a dc link. An improved dynamic model for the ESS is proposed. Based on the proposed model a Proportional-Integral-Resonant (PIR DC link voltage controller is proposed to maintain the DC link voltage through the charging-discharging control of ultracapacitors, capable of working properly under all operating conditions. An extra double frequency component is injected into the UC current by a R controller to dynamically compensate for DC instantaneous power and double frequency AC instantaneous power due to unbalanced grid conditions and disturbances. This feature maintains the DC link voltage constant under unbalanced conditions and increases the degrees of freedom of the DC/AC converter and thus facilitates the application of UCs in microgrids. Simulation and experimental results verify the effectiveness of the proposed control strategy.

  2. Fair cost distribution among smart homes with microgrid

    Zhang, Di; Liu, Songsong; Papageorgiou, Lazaros G.

    2014-01-01

    Highlights: • Work aims at fair cost distribution among smart homes with microgrid. • An MILP-based approach is adopted based on lexicographic minimax method. • Domestic appliances from multiple smart homes are scheduled. • Results from two illustrative examples indicate fair cost distribution. - Abstract: Microgrid is composed of a set of distributed energy resources (DER) and is considered as an alternative energy providing system to the current centralised energy generation. Smart homes equipped with smart grid technology, such as smart meter and communication system, are becoming popular for their lower energy cost and provision of comfort. Flexible energy-consuming household tasks can be scheduled coordinately among multiple homes which share the common microgrid. When local DERs cannot fulfill the whole demand, smart homes will compete with each other to obtain energy from local DERs and achieve their respective lowest energy cost. In this paper, a mathematical programming formulation is presented for the fair cost distribution among smart homes with microgrid. The proposed model is based on the lexicographic minimax method using a mixed integer linear programming (MILP) approach. One-day forecasted energy cost of each smart home is minimised under fairness concern. DER operation, DER output sharing among smart homes and electricity consumption household tasks are scheduled. Two numerical examples with 10 and 50 smart homes are studied. The computational results illustrate that the proposed approach can obtain obvious cost savings (30% and 24% respectively) and fair cost distribution among multiple homes under given fairness scenario

  3. Voltage Quality Improvement in Islanded Microgrids Supplying Nonlinear Loads

    T. Dehghani, Mohammad; Vahedi, Abolfazl; Savaghebi, Mehdi

    2012-01-01

    The aim of this paper is to improve voltage quality at the terminals of distributed generators (DGs) in an islanded microgrid. To achieve this goal, it is proposed to include separate voltage and current control loops for the fundamental and harmonics frequencies. This way, it is not necessary...

  4. Grid-Connected Inverter for Distributed Generation in Microgrid

    Naderipour, Amirreza; Miveh, Mohammad Reza; Guerrero, Josep M.

    for power generation. DGS units can operate in parallel to the main grid or in a Microgrid (MG) mode. An MG is a discrete energy system consisting of DGSs and loads capable of operating in parallel with, or independently from, the main grid. Meanwhile, Grid-Connected Inverters (GCIs) are typically used...

  5. Impact of the Voltage Dips in Shipboard Microgrid Power Systems

    Liu, Wenzhao; Guerrero, Josep M.; Savaghebi, Mehdi

    2017-01-01

    Voltage and frequency transient variations are the most common power quality issues in a ship microgrid system. In this paper, the impacts of the voltage dips induced by the sudden-load of ballast pump are analyzed in detail for the ship power systems. Several relevant ship power quality standards...

  6. Dynamic Energy Management System for a Smart Microgrid.

    Venayagamoorthy, Ganesh Kumar; Sharma, Ratnesh K; Gautam, Prajwal K; Ahmadi, Afshin

    2016-08-01

    This paper presents the development of an intelligent dynamic energy management system (I-DEMS) for a smart microgrid. An evolutionary adaptive dynamic programming and reinforcement learning framework is introduced for evolving the I-DEMS online. The I-DEMS is an optimal or near-optimal DEMS capable of performing grid-connected and islanded microgrid operations. The primary sources of energy are sustainable, green, and environmentally friendly renewable energy systems (RESs), e.g., wind and solar; however, these forms of energy are uncertain and nondispatchable. Backup battery energy storage and thermal generation were used to overcome these challenges. Using the I-DEMS to schedule dispatches allowed the RESs and energy storage devices to be utilized to their maximum in order to supply the critical load at all times. Based on the microgrid's system states, the I-DEMS generates energy dispatch control signals, while a forward-looking network evaluates the dispatched control signals over time. Typical results are presented for varying generation and load profiles, and the performance of I-DEMS is compared with that of a decision tree approach-based DEMS (D-DEMS). The robust performance of the I-DEMS was illustrated by examining microgrid operations under different battery energy storage conditions.

  7. Smart Power Management of DC Microgrids in Future Milligrids

    Peyghami, Saeed; Mokhtari, Hossein; Davari, Pooya

    2016-01-01

    In this paper a novel droop approach for power management in low voltage dc MicroGrids (MGs) based on a master-slave concept is presented. A virtual frequency is injected by a master unit, which is proportional to its output power. Other slave units determine their output power according to the c...

  8. Modeling of an autonomous microgrid for renewable energy sources integration

    Serban, I.; Teodorescu, Remus; Guerrero, Josep M.

    2009-01-01

    The frequency stability analysis in an autonomous microgrid (MG) with renewable energy sources (RES) is a continuously studied issue. This paper presents an original method for modeling an autonomous MG with a battery energy storage system (BESS) and a wind power plant (WPP), with the purpose...

  9. Team-oriented Adaptive Droop Control for Autonomous AC Microgrids

    Shafiee, Qobad; Nasirian, Vahidreza; Guerrero, Josep M.

    2014-01-01

    This paper proposes a distributed control strategy for voltage and reactive power regulation in ac Microgrids. First, the control module introduces a voltage regulator that maintains the average voltage of the system on the rated value, keeping all bus voltages within an acceptable range. Dynamic...

  10. Cost-prioritized droop schemes for autonomous microgrids

    Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Droop schemes for parallel source control usually aims for proportional power sharing tuned in accordance to the source ratings. This works fine for sources with close similarity, but not really for an autonomous microgrid where different types of Distributed Generators (DGs) may be present without...

  11. Control Design of VSIs to Enhance Transient Performance in Microgrids

    Federico, de Bosio; Antonio DeSouza Ribeiro, Luiz; Savaghebi, Mehdi

    2016-01-01

    This paper discusses the control design for an islanded microgrid in order to ensure acceptable performance in terms of voltage quality and load sharing by focusing on transient conditions. To this aim, state feedback decoupling approach has been applied. Experimental tests have been performed...

  12. International Microgrid Assessment. Governance, INcentives, and Experience (IMAGINE)

    Marnay, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Qu, Min [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Romankiewicz, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-06-01

    Microgrids can provide an avenue for increasing the amount of distributed generation and delivery of electricity, where control is more dispersed and quality of service is locally tailored to end-use requirements. Much of this functionality is very different from the predominant utility model to date of centralized power production which is then transmitted and distributed across long distances with a uniform quality of service. This different functionality holds much promise for positive change, in terms of increasing reliability, energy efficiency, and renewable energy while decreasing and carbon emissions. All of these functions should provide direct cost savings for customers and utilities as well as positive externalities for society. As we have seen from the international experience, allowing microgrids to function in parallel with the grid requires some changes in electricity governance and incentives to capture cost savings and actively price in positive externalities. If China can manage to implement these governance changes and create those incentive policies, it will go beyond the establishment of a successful microgrid demonstration program and become an international leader in microgrid deployment.

  13. Tertiary Control for Optimal Unbalance Compensation in Islanded Microgrids

    Meng, Lexuan; Tang, Fen; Savaghebi, Mehdi

    2014-01-01

    In order to achieve desirable power quality in the critical bus (CB) in microgrids, primary and secondary control can be used to realize unbalance compensation and at the same time, to make distributed generators (DGs) share the compensation efforts. Considering that the power quality requirement...

  14. Design of an adaptive overcurrent protection scheme for microgrids ...

    Microgrid is a new phenomenon regarded to Distributed Generation (DG) penetration in the existing distribution systems. In this paper adaptive over current (OC) protection technique for a distribution system with DG penetration is proposed. This scheme takes into account general protection requirements, impacts of DG on ...

  15. Optimal sizing of energy storage system for microgrids

    Microgrids (MGs) are Low Voltage distribution networks comprising various distributed generators (DG), storage devices and controllable loads that can operate either interconnected or isolated from the main distribution grid as a controlled entity. Energy storage system (ESS) is a vital part of an MG. In this paper, a ...

  16. Optimization of multi-objective micro-grid based on improved particle swarm optimization algorithm

    Zhang, Jian; Gan, Yang

    2018-04-01

    The paper presents a multi-objective optimal configuration model for independent micro-grid with the aim of economy and environmental protection. The Pareto solution set can be obtained by solving the multi-objective optimization configuration model of micro-grid with the improved particle swarm algorithm. The feasibility of the improved particle swarm optimization algorithm for multi-objective model is verified, which provides an important reference for multi-objective optimization of independent micro-grid.

  17. An optimization-based control approach for reliable microgrid energy management under uncertainties

    Prodan , Ionela; Zio , Enrico

    2013-01-01

    International audience; This paper proposes an optimizationbased control approach for microgrid energy management. For exemplification of the approach consider a microgrid system connected to an external grid via a transformer and containing a local consumer, a renewable generator (wind turbine) and a storage facility (battery). The objective of minimizing the costs is achieved through a predictive control framework for scheduling the battery usage in the microgrid system. The proposed contro...

  18. Application research of power allocation based on Buck circuit in DC microgrid

    Wang Zihao; Zhou Mingyu

    2017-01-01

    In a traditional DC microgrid, the power sharing control strategy has been always used in the distributed power converters, resulting in not making outer power allocation arbitrarily. In order to solve the power output allocation problem of wind power in DC microgrid, the intelligent Buck circuit based on PI algorithm and the load current feed-forward method was used to realize the arbitrary regulation of the output power of the wind power in the DC microgrid system. Compared with traditional...

  19. DC microgrids providing frequency regulation in electrical power system - imperfect communication issues

    Bašić, Hrvoje; Dragicevic, Tomislav; Pandžić, Hrvoje

    2017-01-01

    This paper presents a model of multiple DC microgrids with battery energy storage systems and demand response capability, taking part in primary frequency regulation of electrical power system. Although DC microgrids can contribute to stability and efficiency of frequency regulation, these complex...... systems may cause serious stability issues due to the imperfect communication. This work presents possible scenarios of unstable primary frequency regulation in a simplified model of electrical power system with DC microgrids, which are controlled through communication network....

  20. Designing an Energy Storage System Fuzzy PID Controller for Microgrid Islanded Operation

    Jong-Yul Kim; Hak-Man Kim; Seul-Ki Kim; Jin-Hong Jeon; Heung-Kwan Choi

    2011-01-01

    Recently, interest in microgrids, which are composed of distributed generation (DG), distributed storage (DS), and loads, has been growing as a potentially effective clean energy system to mitigate against climate change. The microgrid is operated in the grid-connected mode and the islanded mode according to the conditions of the upstream power grid. The role of the energy storage system (ESS) is especially important to maintain constant the frequency and voltage of an islanded microgrid. For...

  1. Finite-Control-Set Model Predictive Control (FCS-MPC) for Islanded Hybrid Microgrids

    Yi, Zhehan; Babqi, Abdulrahman J.; Wang, Yishen; Shi, Di; Etemadi, Amir H.; Wang, Zhiwei; Huang, Bibin

    2018-01-01

    Microgrids consisting of multiple distributed energy resources (DERs) provide a promising solution to integrate renewable energies, e.g., solar photovoltaic (PV) systems. Hybrid AC/DC microgrids leverage the merits of both AC and DC power systems. In this paper, a control strategy for islanded multi-bus hybrid microgrids is proposed based on the Finite-Control-Set Model Predictive Control (FCS-MPC) technologies. The control loops are expedited by predicting the future states and determining t...

  2. Managing risks of market price uncertainty for a microgrid operation

    Raghavan, Sriram

    After deregulation of electricity in the United States, the day-ahead and real-time markets allow load serving entities and generation companies to bid and purchase/sell energy under the supervision of the independent system operator (ISO). The electricity market prices are inherently uncertain, and can be highly volatile. The main objective of this thesis is to hedge against the risk from the uncertainty of the market prices when purchasing/selling energy from/to the market. The energy manager can also schedule distributed generators (DGs) and storage of the microgrid to meet the demand, in addition to energy transactions from the market. The risk measure used in this work is the variance of the uncertain market purchase/sale cost/revenue, assuming the price following a Gaussian distribution. Using Markowitz optimization, the risk is minimized to find the optimal mix of purchase from the markets. The problem is formulated as a mixed integer quadratic program. The microgrid at Illinois Institute of Technology (IIT) in Chicago, IL was used as a case study. The result of this work reveals the tradeoff faced by the microgrid energy manager between minimizing the risk and minimizing the mean of the total operating cost (TOC) of the microgrid. With this information, the microgrid energy manager can make decisions in the day-ahead and real-time markets according to their risk aversion preference. The assumption of market prices following Gaussian distribution is also verified to be reasonable for the purpose of hedging against their risks. This is done by comparing the result of the proposed formulation with that obtained from the sample market prices randomly generated using the distribution of actual historic market price data.

  3. Modeling and optimization of energy storage system for microgrid

    Qiu, Xin

    The vanadium redox flow battery (VRB) is well suited for the applications of microgrid and renewable energy. This thesis will have a practical analysis of the battery itself and its application in microgrid systems. The first paper analyzes the VRB use in a microgrid system. The first part of the paper develops a reduced order circuit model of the VRB and analyzes its experimental performance efficiency during deployment. The statistical methods and neural network approximation are used to estimate the system parameters. The second part of the paper addresses the implementation issues of the VRB application in a photovoltaic-based microgrid system. A new dc-dc converter was proposed to provide improved charging performance. The paper was published on IEEE Transactions on Smart Grid, Vol. 5, No. 4, July 2014. The second paper studies VRB use within a microgrid system from a practical perspective. A reduced order circuit model of the VRB is introduced that includes the losses from the balance of plant including system and environmental controls. The proposed model includes the circulation pumps and the HVAC system that regulates the environment of the VRB enclosure. In this paper, the VRB model is extended to include the ESS environmental controls to provide a model that provides a more realistic efficiency profile. The paper was submitted to IEEE Transactions on Sustainable Energy. Third paper discussed the optimal control strategy when VRB works with other type of battery in a microgird system. The work in first paper is extended. A high level control strategy is developed to coordinate a lead acid battery and a VRB with reinforcement learning. The paper is to be submitted to IEEE Transactions on Smart Grid.

  4. Optimal load scheduling in commercial and residential microgrids

    Ganji Tanha, Mohammad Mahdi

    Residential and commercial electricity customers use more than two third of the total energy consumed in the United States, representing a significant resource of demand response. Price-based demand response, which is in response to changes in electricity prices, represents the adjustments in load through optimal load scheduling (OLS). In this study, an efficient model for OLS is developed for residential and commercial microgrids which include aggregated loads in single-units and communal loads. Single unit loads which include fixed, adjustable and shiftable loads are controllable by the unit occupants. Communal loads which include pool pumps, elevators and central heating/cooling systems are shared among the units. In order to optimally schedule residential and commercial loads, a community-based optimal load scheduling (CBOLS) is proposed in this thesis. The CBOLS schedule considers hourly market prices, occupants' comfort level, and microgrid operation constraints. The CBOLS' objective in residential and commercial microgrids is the constrained minimization of the total cost of supplying the aggregator load, defined as the microgrid load minus the microgrid generation. This problem is represented by a large-scale mixed-integer optimization for supplying single-unit and communal loads. The Lagrangian relaxation methodology is used to relax the linking communal load constraint and decompose the independent single-unit functions into subproblems which can be solved in parallel. The optimal solution is acceptable if the aggregator load limit and the duality gap are within the bounds. If any of the proposed criteria is not satisfied, the Lagrangian multiplier will be updated and a new optimal load schedule will be regenerated until both constraints are satisfied. The proposed method is applied to several case studies and the results are presented for the Galvin Center load on the 16th floor of the IIT Tower in Chicago.

  5. Distributed Secondary Control for Islanded MicroGrids – A Networked Control Systems Approach

    Shafiee, Qobad; Vasquez, Juan Carlos; Guerrero, Josep M.

    2012-01-01

    This paper presents a novel approach to conceive the secondary control in droop-controlled MicroGrids. The conventional approach is based on restoring the frequency and amplitude deviations produced by the local droop controllers by using a MicroGrid Central Controller. A distributed networked...... control system is used in order to implement a distributed secondary control thus avoiding the use of a MicroGrid Central Control. The proposed approach is not only able to restore frequency and voltage of the MicroGrid but also ensures reactive power sharing. The distributed secondary control do...

  6. A Multiagent System for Autonomous Operation of Islanded Microgrids Based on a Power Market Environment

    Myong-Chul Shin

    2010-12-01

    Full Text Available One of the most important requirements of microgrid operation is to maintain a constant frequency such as 50 Hz or 60 Hz, which is closely related to a power balance between supply and demand. In general, microgrids are connected to power grids and surplus/shortage power of microgrids is traded with power grids. Since islanded microgrids are isolated from any power grids, the decrease in generation or load-shedding can be used to maintain the frequency when a power imbalance between supply and demand occurs. The power imbalance restricts the electricity use of consumers in the case of supply shortage and the power supply of suppliers in the case of supply surplus. Therefore, the islanded microgrid should be operated to reduce power imbalance conditions. Meanwhile, the microgrid is a small-scale power system and the employment of skillful operators for effective operation of its components requires high costs. Therefore, automatic operation of the components is effective realistically. In addition, the components are distributed in the microgrid and their operation should consider their owners’ profits. For these reasons, a multiagent system application can be a good alternative for microgrid operation. In this paper, we present a multiagent system for autonomous operation of the islanded microgrid on a power market environment. The proposed multiagent system is designed based on a cooperative operation scheme. We show the functionality and the feasibility of the proposed multiagent system through several tests.

  7. A multiagent system for autonomous operation of islanded microgrids based on a power market environment

    Kim, H.-M. [Department of Electrical Engineering, University of Incheon/12-1, Sondo-dong, Yeonsu-gu, Incheon, 406-840 (Korea, Republic of); Kinoshita, T. [Graduate School of Information Science, Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Shin, M.-Ch. [School of Information and Communication Engineering, Sungkyunkwan University/300, Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do, 440-746 (Korea, Republic of)

    2010-12-15

    One of the most important requirements of microgrid operation is to maintain a constant frequency such as 50 Hz or 60 Hz, which is closely related to a power balance between supply and demand. In general, microgrids are connected to power grids and surplus/shortage power of microgrids is traded with power grids. Since islanded microgrids are isolated from any power grids, the decrease in generation or load-shedding can be used to maintain the frequency when a power imbalance between supply and demand occurs. The power imbalance restricts the electricity use of consumers in the case of supply shortage and the power supply of suppliers in the case of supply surplus. Therefore, the islanded microgrid should be operated to reduce power imbalance conditions. Meanwhile, the microgrid is a small-scale power system and the employment of skillful operators for effective operation of its components requires high costs. Therefore, automatic operation of the components is effective realistically. In addition, the components are distributed in the microgrid and their operation should consider their owners' profits. For these reasons, a multiagent system application can be a good alternative for microgrid operation. In this paper, we present a multiagent system for autonomous operation of the islanded microgrid on a power market environment. The proposed multiagent system is designed based on a cooperative operation scheme. We show the functionality and the feasibility of the proposed multiagent system through several tests. (authors)

  8. Dynamic Equivalent Modeling of a Grid-Tied Microgrid Based on Characteristic Model and Measurement Data

    Changchun Cai

    2017-11-01

    Full Text Available Microgrids can significantly improve the utilization of distributed generation (DG and the reliability of the power supply. However, in the grid-tied operational mode, the interaction between the microgrid and the distribution network cannot be ignored. The paper proposes an equivalent modeling method for the microgrid under grid-tied mode based on a characteristic model. It can simplify the microgrid model in the numerical simulation of the distribution network. The proposed equivalent model can present the dynamic response of a microgrid but not miss any of its primary characteristics. The characteristic model is represented by a low-order time-varying differential equation with the same characteristics of the original microgrid system. During the modeling process, the voltage and the power exchanged between the microgrid and distribution network are collected as the training data for the identification of model parameters. A recursive damped least squares algorithm (RDLS is used for the parameter identification. A microgrid system containing different DGs is built to test the proposed modeling method in DIgSILENT, and the results show that the proposed dynamic equivalent modeling method is effective and the characteristic model can present the dynamic behaviors of the detailed model of a microgrid.

  9. Reinforcement learning for microgrid energy management

    Kuznetsova, Elizaveta; Li, Yan-Fu; Ruiz, Carlos; Zio, Enrico; Ault, Graham; Bell, Keith

    2013-01-01

    We consider a microgrid for energy distribution, with a local consumer, a renewable generator (wind turbine) and a storage facility (battery), connected to the external grid via a transformer. We propose a 2 steps-ahead reinforcement learning algorithm to plan the battery scheduling, which plays a key role in the achievement of the consumer goals. The underlying framework is one of multi-criteria decision-making by an individual consumer who has the goals of increasing the utilization rate of the battery during high electricity demand (so as to decrease the electricity purchase from the external grid) and increasing the utilization rate of the wind turbine for local use (so as to increase the consumer independence from the external grid). Predictions of available wind power feed the reinforcement learning algorithm for selecting the optimal battery scheduling actions. The embedded learning mechanism allows to enhance the consumer knowledge about the optimal actions for battery scheduling under different time-dependent environmental conditions. The developed framework gives the capability to intelligent consumers to learn the stochastic environment and make use of the experience to select optimal energy management actions. - Highlights: • A consumer exploits a 2 steps-ahead reinforcement learning for battery scheduling. • The Q-learning based mechanism is fed by the predictions of available wind power. • Wind speed state evolutions are modeled with a Markov chain model. • Optimal scheduling actions are learned through the occurrence of similar scenarios. • The consumer manifests a continuous enhance of his knowledge about optimal actions

  10. Balancing collective and individual interests in transactive energy management of interconnected micro-grid clusters

    Chen, Yang; Hu, Mengqi

    2016-01-01

    The emerging technology, transactive energy network, can allow multiple interconnected micro-grids (a.k.a. micro-grid clusters) to exchange energy for greater energy efficiency. Existing research has demonstrated that the micro-grid clusters can achieve some collective interests (e.g., minimizing total energy cost). However, some micro-grids may have to make sacrifices of their individual interests (e.g., increasing cost) for collective interests of the clusters. To bridge these research gaps, we propose four different transactive energy management models for micro-grid clusters where each micro-grid is allowed to have energy transactions with others. The first model focuses on maximizing collective interests, both the collective and individual interests are considered in the second model, and the last two models aim to maximize both the collective and individual interests. The performances of the proposed models are evaluated using a cluster of sixteen micro-grids with different energy profiles. It is demonstrated that 1) all of the four models can maximize the collective interests, 2) the third model can maximize the relative individual interests where each micro-grid can achieve the same percentage of cost savings as the clusters, and 3) the fourth model can maximize the absolute individual interests where each micro-grid can achieve the same amount of cost savings. - Highlights: • A modeling framework is developed for transactive energy management of the micro-grid clusters. • Four operation decision models are developed to balance the collective and individual interests. • The prices of local energy transaction are modeled. • The micro-grid clusters can achieve 15.34% energy cost savings.

  11. Microgrids: An emerging paradigm for meeting building electricity and heat requirements efficiently and with appropriate energy quality

    Marnay, Chris; Firestone, Ryan [Berkeley Lab MS 90R4000 (United States)

    2007-07-01

    The first major paradigm shift in electricity generation, delivery, and control is emerging in the developed world, notably Europe, North America, and Japan. This shift will move electricity supply away from the highly centralised universal service quality model with which we are familiar today towards a more dispersed system with heterogeneous qualities of service. One element of dispersed control is the clustering of sources and sinks into semi-autonomous {mu}grids (microgrids). Research, development, demonstration, and deployment (RD3) of {mu}grids are advancing rapidly on at least three continents, and significant demonstrations are currently in progress. This paradigm shift will result in more electricity generation close to end-uses, often involving combined heat and power application for building heating and cooling, increased local integration of renewables, and the possible provision of heterogeneous qualities of electrical service to match the requirements of various end-uses. In Europe, microgrid RD3 is entering its third major round under the 7th European Commission Framework Programme; in the U.S., one specific microgrid concept is undergoing rigorous laboratory testing, and in Japan, where the most activity exists, four major publicly sponsored and two privately sponsored demonstrations are in progress. This evolution poses new challenges to the way buildings are designed, built, and operated. Traditional building energy supply systems will become much more complex in at least three ways: 1. one cannot simply assume gas arrives at the gas meter, electricity at its meter, and the two systems are virtually independent of one another; rather, energy conversion, heat recovery and use, and renewable energy harvesting may all be taking place simultaneously within the building energy system; 2. the structure of energy flows in the building must accommodate multiple energy processes in a manner that permits high overall efficiency; and 3. multiple qualities

  12. Modeling and Analysis of Remote, Off-grid Microgrids

    Madathil, Sreenath Chalil

    Over the past century the electric power industry has evolved to support the delivery of power over long distances with highly interconnected transmission systems. Despite this evolution, some remote communities are not connected to these systems. These communities rely on small, disconnected distribution systems, i.e., microgrids, to deliver power. Power distribution in most of these remote communities often depend on a type of microgrid called "off-grid microgrids". However, as microgrids often are not held to the same reliability standards as transmission grids, remote communities can be at risk to experience extended blackouts. Recent trends have also shown an increased use of renewable energy resources in power systems for remote communities. The increased penetration of renewable resources in power generation will require complex decision making when designing a resilient power system. This is mainly due to the stochastic nature of renewable resources that can lead to loss of load or line overload during their operations. In the first part of this thesis, we develop an optimization model and accompanying solution algorithm for capacity planning and operating microgrids that include N-1 security and other practical modeling features (e.g., AC power flow physics, component efficiencies and thermal limits). We demonstrate the effectiveness of our model and solution approach on two test systems: a modified version of the IEEE 13 node test feeder and a model of a distribution system in a remote Alaskan community. Once a tractable algorithm was identified to solve the above problem, we develop a mathematical model that includes topology design of microgrids. The topology design includes building new lines, making redundant lines, and analyzing N-1 contingencies on generators and lines. We develop a rolling horizon algorithm to efficiently analyze the model and demonstrate the strength of our algorithm in the same network. Finally, we develop a stochastic model that

  13. Micro-Grids for Colonias (TX)

    Dean Schneider; Michael Martin; Renee Berry; Charles Moyer

    2012-07-31

    This report describes the results of the final implementation and testing of a hybrid micro-grid system designed for off-grid applications in underserved Colonias along the Texas/Mexico border. The project is a federally funded follow-on to a project funded by the Texas State Energy Conservation Office in 2007 that developed and demonstrated initial prototype hybrid generation systems consisting of a proprietary energy storage technology, high efficiency charging and inverting systems, photovoltaic cells, a wind turbine, and bio-diesel generators. This combination of technologies provided continuous power to dwellings that are not grid connected, with a significant savings in fuel by allowing power generation at highly efficient operating conditions. The objective of this project was to complete development of the prototype systems and to finalize and engineering design; to install and operate the systems in the intended environment, and to evaluate the technical and economic effectiveness of the systems. The objectives of this project were met. This report documents the final design that was achieved and includes the engineering design documents for the system. The system operated as designed, with the system availability limited by maintenance requirements of the diesel gensets. Overall, the system achieved a 96% availability over the operation of the three deployed systems. Capital costs of the systems were dependent upon both the size of the generation system and the scope of the distribution grid, but, in this instance, the systems averaged $0.72/kWh delivered. This cost would decrease significantly as utilization of the system increased. The system with the highest utilization achieved a capitol cost amortized value of $0.34/kWh produced. The average amortized fuel and maintenance cost was $0.48/kWh which was dependent upon the amount of maintenance required by the diesel generator. Economically, the system is difficult to justify as an alternative to grid

  14. Power scheduling in islanded-mode microgrids using fuel cell vehicles

    Alavi, Farid; Van De Wouw, Nathan; De Schutter, Bart

    2018-01-01

    We consider power scheduling in a microgrid operated in the islanded mode. It is assumed that at any time all the renewable energy sources are generating the maximum achievable electrical power based on the weather conditions and the power balance of the microgrid is exclusively done by a fleet of

  15. Research on DC Micro-grid system of photovoltaic power generation

    Zheng, Yiming; Wang, Xiaohui

    2018-01-01

    The use of energy has become a topic of concern, the demand of people for power grows in number or quantity with the development of economy. It is necessary to consider using new forms of power supply-microgrid system for distributed power supply. The power supply mode can not only effectively solve the problem of excessive line loss in the large power grid, but also can increase the reliability of the power supply, and is economical and environmental friendly. With the increasing of DC loads, in order to improve the utilization efficiency, the DC microgrid power supply problems are begin to be researched and integrated with the renewable energy sources. This paper researched the development of microgrid, compared AC microgrid with DC microgrid, summarized the distribution of DC bus voltage level, the DC microgrid network form, the control mode and the main power electronics elements of DC microgrid of photovoltaic power generation system. Today, the DC microgrid system is still in the development stage without uniform voltage level standard, however, it will come into service in the future.

  16. Application of a microgrid with renewables for a water treatment plant

    Soshinskaya, Mariya; Crijns - Graus, Wina|info:eu-repo/dai/nl/308005015; van der Meer, Jos; Guerrero, Josep M.

    2014-01-01

    This research explores the techno-economic potential for a predominantly renewable electricity-based microgrid serving an industrial-sized drink water plant in the Netherlands. Grid-connected and stand-alone microgrid scenarios were modeled, utilizing measured wind speed and solar irradiation data,

  17. Multiple Distributed Smart Microgrids with a Self-Autonomous, Energy Harvesting Wireless Sensor Network

    Guerrero, Josep M.; Kheng Tan, Yen

    2012-01-01

    The chapter covers the smart wireless sensors for microgrids, as well as the energy harvesting technology used to sustain the operations of these sensors. Last, a case study on the multiple distributed smart microgrids with a self-autonomous, energy harvesting wireless sensor network is presented....

  18. A coordinated dispatch model for electricity and heat in a Microgrid via particle swarm optimization

    Xu, Lizhong; Yang, Guangya; Xu, Zhao

    2013-01-01

    This paper develops a coordinated electricity and heat dispatching model for Microgrid under day-ahead environment. In addition to operational constraints, network loss and physical limits are addressed in this model, which are always ignored in previous work. As an important component of Microgrid...

  19. An estimator-based distributed voltage-predictive control strategy for ac islanded microgrids

    Wang, Yanbo; Chen, Zhe; Wang, Xiongfei

    2015-01-01

    This paper presents an estimator-based voltage predictive control strategy for AC islanded microgrids, which is able to perform voltage control without any communication facilities. The proposed control strategy is composed of a network voltage estimator and a voltage predictive controller for each...... and has a good capability to reject uncertain perturbations of islanded microgrids....

  20. Research on a Microgrid Subsidy Strategy Based on Operational Efficiency of the Industry Chain

    Yong Long

    2018-05-01

    Full Text Available Government subsidy is a powerful tool to motivate the development of a new energy industry. At the early stage of microgrid development, for the sake of the cost and benefit issue, it is necessary for the government to subsidize so as to support and promote the development of microgrids. However, a big challenge in practice is how to optimize the operational efficiency of the microgrid industry chain with varying targets and methods of subsidy. In order to explore this problem, we construct a subsidy model based on the microgrid industry chain, involving government, investor, operator, equipment supplier, and user. Through calculation and solution of this model, we obtain price and return indicators of each microgrid industry chain participant when the subsidy target differs. Based on that, we contrast and compare the optimal subsidy strategy and influencing factors when operational efficiency indicators vary. Finally, we validate and analyze this model with numerical analysis and discuss the impact of development stage, technological level, and change in subsidy amount on the operational efficiency of the microgrid industry chain and on the returns of each participant. This result is of great significance to subsidy practice for microgrids and the development of microgrids.

  1. Transient Monitoring Function–Based Fault Detection for Inverter-Interfaced Microgrids

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Mehrizi-Sani, Ali

    2018-01-01

    One of the major challenges in protection of the inverter-interfaced islanded microgrids is their limited fault current level. This degrades the performance of traditional overcurrent protection schemes. This paper proposes a fault detection strategy based on monitoring the transient response......-domain simulation case studies using the CIGRE benchmark low voltage microgrid network....

  2. Control and EMS of a Grid-Connected Microgrid with Economical Analysis

    Mohamed El-Hendawi

    2018-01-01

    Full Text Available Recently, significant development has occurred in the field of microgrid and renewable energy systems (RESs. Integrating microgrids and renewable energy sources facilitates a sustainable energy future. This paper proposes a control algorithm and an optimal energy management system (EMS for a grid-connected microgrid to minimize its operating cost. The microgrid includes photovoltaic (PV, wind turbine (WT, and energy storage systems (ESS. The interior search algorithm (ISA optimization technique determines the optimal hour-by-hour scheduling for the microgrid system, while it meets the required load demand based on 24-h ahead forecast data. The control system consists of three stages: EMS, supervisory control and local control. EMS is responsible for providing the control system with the optimum day-ahead scheduling power flow between the microgrid (MG sources, batteries, loads and the main grid based on an economic analysis. The supervisory control stage is responsible for compensating the mismatch between the scheduled power and the real microgrid power. In addition, this paper presents the local control design to regulate the local power, current and DC voltage of the microgrid. For verification, the proposed model was applied on a real case study in Oshawa (Ontario, Canada with various load conditions.

  3. A Simplified Control Method for Tie-Line Power of DC Micro-Grid

    Yanbo Che

    2018-04-01

    Full Text Available Compared with the AC micro-grid, the DC micro-grid has low energy loss and no issues of frequency stability, which makes it more accessible for distributed energy. Thus, the DC micro-grid has good potential for development. A variety of renewable energy is included in the DC micro-grid, which is easily affected by the environment, causing fluctuation of the DC voltage. For grid-connected DC micro-grid with droop control strategy, the tie-line power is affected by fluctuations in the DC voltage, which sets higher requirements for coordinated control of the DC micro-grid. This paper presents a simplified control method to maintain a constant tie-line power that is suitable for the DC micro-grid with the droop control strategy. By coordinating the designs of the droop control characteristics of generators, energy storage units and grid-connected inverter, a dead band is introduced to the droop control to improve the system performance. The tie-line power in the steady state is constant. When a large disturbance occurs, the AC power grid can provide power support to the micro-grid in time. The simulation example verifies the effectiveness of the proposed control strategy.

  4. SoC-Based Droop Method for Distributed Energy Storage in DC Microgrid Applications

    Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.

    2012-01-01

    With the progress of distributed generation nowadays, microgrid is employed to integrate different renewable energy sources into a certain area. For several kinds of renewable sources have DC outputs, DC microgrid has drawn more attention recently. Meanwhile, to deal with the uncertainty...

  5. Hierarchical Control of Droop-Controlled DC and AC Microgrids - A General Approach Towards Standardization

    Guerrero, Josep M.; Vásquez, Juan V.; Teodorescu, Remus

    2009-01-01

    DC and AC Microgrids are key elements to integrate renewable and distributed energy resources as well as distributed energy storage systems. In the last years, efforts toward the standardization of these Microgrids have been made. In this sense, this paper present the hierarchical control derived...

  6. Online Energy Management System for Distributed Generators in a Grid-Connected Microgrid

    Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Graells, Moises

    2015-01-01

    A microgrid is an energy subsystem composed of generation units, energy storage, and loads that requires power management in order to supply the load properly according to defined objectives. This paper proposes an online energy management system for a storage based grid-connected microgrid...

  7. A new virtual-flux-vector based droop control strategy for parallel connected inverters in microgrids

    Hu, Jiefeng; Zhu, Jianguo; Qu, Yanqing

    2013-01-01

    Voltage and frequency droop method is commonly used in microgrids to achieve proper autonomous power sharing without rely on intercommunication systems. This paper proposes a new control strategy for parallel connected inverters in microgrid applications by drooping the flux instead of the invert...

  8. Impacts of P-f & Q-V Droop Control on MicroGrids Transient Stability

    Zhao-xia, Xiao; Hong-wei, Fang

    Impacts of P-f & Q-V droop control on MicroGrid transient stability was investigated with a wind unit of asynchronous generator in the MicroGrid. The system frequency stability was explored when the motor load starts and its load power changes, and faults of different types and different locations occurs. The simulations were done by PSCAD/EMTDC.

  9. Dynamic Consensus Algorithm Based Distributed Global Efficiency Optimization of a Droop Controlled DC Microgrid

    Meng, Lexuan; Dragicevic, Tomislav; Guerrero, Josep M.

    2014-01-01

    In a DC microgrid, several paralleled conversion systems are installed in distributed substations for transferring power from external grid to a DC microgrid. Droop control is used for the distributed load sharing among all the DC/DC converters. Considering the typical efficiency feature of power...

  10. Generic Community System Specification: A Proposed Format for Reporting the Results of Microgrid Optimization Analysis

    Jimenez, Antonio [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-03-14

    This document provides a proposed format for reporting the results of microgrid optimization analysis. While the proposed format assumes that the modeling is conducted as part of a renewable energy retrofit of an existing diesel micro-grid, the format can certainly be adopted for other situations.

  11. Optimal Power Flow in three-phase islanded microgrids with inverter interfaced units

    Sanseverino, Eleonora Riva; Quang, Ninh Nguyen; Di Silvestre, Maria Luisa

    2015-01-01

    In this paper, the solution of the Optimal Power Flow (OPF) problem for three phase islanded microgrids is studied, the OPF being one of the core functions of the tertiary regulation level for an AC islanded microgrid with a hierarchical control architecture. The study also aims at evaluating the...

  12. Addressing LV network power quality issues through the implementation of a microgrid

    Lava, J.R.T.; Cobben, J.F.G.; Kling, W.L.; Overbeeke, van F.

    2010-01-01

    The results of the implementation of an actual microgrid in the Netherlands are presented. This microgrid has photovoltaic panels as microsources, energy storage, and a flexible AC distribution system (FACDS) that can operate connected to the public grid or autonomously where it regulates the site’s

  13. Assessing the contribution of microgrids to the reliability of distribution networks

    Costa, Paulo Moises [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal); Matos, Manuel A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2009-02-15

    The emergence of microgeneration has recently lead to the concept of microgrid, a network of LV consumers and producers able to export electric energy in some circumstances and also to work in an isolated way in emergency situations. Research on the organization of microgrids, control devices, functionalities and other technical aspects is presently being carried out, in order to establish a consistent technical framework to support the concept. The successful development of the microgrid concept implies the definition of a suitable regulation for its integration on distribution systems. In order to define such a regulation, the identification of costs and benefits that microgrids may bring is a crucial task. Actually, this is the basis for a discussion about the way global costs could be divided among the different agents that benefit from the development of microgrids. Among other aspects, the effect of microgrids on the reliability of the distribution network has been pointed out as an important advantage, due to the ability of isolated operation in emergency situations. This paper identifies the situations where the existence of a microgrid may reduce the interruption rate and duration and thus improve the reliability indices of the distribution network. The relevant expressions necessary to quantify the reliability are presented. An illustrative example is included, where the global influence of the microgrid in the reliability is commented. (author)

  14. Important Factors for Early Market Microgrids: Demand Response and Plug-in Electric Vehicle Charging

    White, David Masaki

    Microgrids are evolving concepts that are growing in interest due to their potential reliability, economic and environmental benefits. As with any new concept, there are many unresolved issues with regards to planning and operation. In particular, demand response (DR) and plug-in electric vehicle (PEV) charging are viewed as two key components of the future grid and both will likely be active technologies in the microgrid market. However, a better understanding of the economics associated with DR, the impact DR can have on the sizing of distributed energy resource (DER) systems and how to accommodate and price PEV charging is necessary to advance microgrid technologies. This work characterizes building based DR for a model microgrid, calculates the DER systems for a model microgrid under DR through a minimization of total cost, and determines pricing methods for a PEV charging station integrated with an individual building on the model microgrid. It is shown that DR systems which consist only of HVAC fan reductions provide potential economic benefits to the microgrid through participation in utility DR programs. Additionally, peak shaving DR reduces the size of power generators, however increasing DR capacity does not necessarily lead to further reductions in size. As it currently stands for a microgrid that is an early adopter of PEV charging, current installation costs of PEV charging equipment lead to a system that is not competitive with established commercial charging networks or to gasoline prices for plug-in hybrid electric vehicles (PHEV).

  15. Addressing low voltage network power quality issues through the implementation of a microgrid

    Lava, J.R.T.; Cobben, J.F.G.; Kling, W.L.; Overbeeke, van F.

    2011-01-01

    The results of the implementation of an actual microgrid in the Netherlands are presented. This microgrid has photovoltaic panels as microsources, energy storage, and a flexible AC distribution interfacing system that can operate connected to the public grid or autonomously where it regulates the

  16. Grid-interfacing converter systems with enhanced voltage quality for microgrid application : concept and implementation

    Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

    2011-01-01

    Grid-interfacing converter systems with enhanced voltage quality are proposed for microgrid application in this paper. By adapting the conventional series-parallel structure, a group of grid-interfacing system topologies are proposed for the purpose of interfacing local generation/microgrid to the

  17. On the construction of operating systems for the Microgrid many-core architecture

    van Tol, M.W.

    2013-01-01

    Michiel van Tol toont in zijn onderzoek aan hoe het mogelijk is om een besturingssysteem te ontwerpen voor Microgrid-technologie Informatici aan de UvA werken aan een nieuw soort processor voor toekomstige computers, de Microgrid-technologie. In dit nieuwe ontwerp wordt een groot aantal rekenkernen

  18. A Robot-Soccer-Coordination Inspired Control Architecture Applied to Islanded Microgrids

    Aldana, Nelson Leonardo Diaz; Guarnizo, Jose Guillermo; Mellado, Martin

    2017-01-01

    of the energy storage systems, may ensure proper and reliable operation of the microgrid. This paper proposes a structured architecture based on tactics, roles and behaviors for a coordinated operation of islanded microgrids. The architecture is inspired on a robot soccer strategy with global perception...

  19. Stability assessment of a multi-port power electronic interface for hybrid micro-grid applications

    Shamsi, Pourya

    Migration to an industrial society increases the demand for electrical energy. Meanwhile, social causes for preserving the environment and reducing pollutions seek cleaner forms of energy sources. Therefore, there has been a growth in distributed generation from renewable sources in the past decade. Existing regulations and power system coordination does not allow for massive integration of distributed generation throughout the grid. Moreover, the current infrastructures are not designed for interfacing distributed and deregulated generation. In order to remedy this problem, a hybrid micro-grid based on nano-grids is introduced. This system consists of a reliable micro-grid structure that provides a smooth transition from the current distribution networks to smart micro-grid systems. Multi-port power electronic interfaces are introduced to manage the local generation, storage, and consumption. Afterwards, a model for this micro-grid is derived. Using this model, the stability of the system under a variety of source and load induced disturbances is studied. Moreover, pole-zero study of the micro-grid is performed under various loading conditions. An experimental setup of this micro-grid is developed, and the validity of the model in emulating the dynamic behavior of the system is verified. This study provides a theory for a novel hybrid micro-grid as well as models for stability assessment of the proposed micro-grid.

  20. Dynamic-Phasor-Based Nonlinear Modelling of AC Islanded Microgrids Under Droop Control

    Mariani, Valerio; Vasca, Francesco; Guerrero, Josep M.

    2014-01-01

    Droop controlled inverters are widely used in islanded microgrids to interface distributed energy resources and to provide for the loads active and reactive powers demand. In this scenario, an important issue is to assess the stability of the microgrids taking into account the network and currents...

  1. A Control Architecture to Coordinate Renewable Energy Sources and Energy Storage Systems in Islanded Microgrids

    Wu, Dan; Tang, Fen; Dragicevic, Tomislav

    2015-01-01

    Coordinated operation of microgrids requires that energy management system takes into account both the available power in renewable energy sources (RES) and storage capacity of energy storage systems (ESS). In this paper, a coordinated architecture of islanded AC microgrids with smooth switching...

  2. A Novel Coordinated Control of Renewable Energy Sources and Energy Storage System in Islanded Microgrid

    Gui, Yonghao; Li, Mingshen; Guerrero, Josep M.

    2018-01-01

    A novel coordinated control for energy storage system (ESS) and renewable energy source (RES) units is proposed in islanded AC microgrids without a phase-locked loop system. We use a proportional-resonant control technique for the ESS, which fixes the voltage and frequency of the microgrid...

  3. Coordinated Control Based on Bus-Signaling and Virtual Inertia for Islanded DC Microgrids

    Wu, Dan; Tang, Fen; Dragicevic, Tomislav

    2015-01-01

    A low-voltage DC islanded microgrid contains a number of renewable energy sources (RES), local loads, and energy storage systems (ESS). To avoid the over-charging and over-discharging situations of ESS, a coordinated control strategy should be used in DC islanded microgrids. In this paper, a nove...

  4. Solutions for Remote Island Microgrids: Discussion and analysis of Indonesia’s remote island energy system

    Ma, Zheng; Jørgensen, Bo Nørregaard; Santos, Athila Quaresma

    2018-01-01

    to mitigate this issue. This paper uses Indonesia as an example to investigate, develop and evaluate the potential microgrid solutions for the remote islands. There are six potential microgrid solutions are discussed, and two solutions (photovoltaic cells and storage; diesel generator, photovoltaic cells...

  5. Microgrid planning based on fuzzy interval prediction models of renewable resources

    Morales, R.; Sáez, D.; Marín, L.G.; Nunez Vicencio, Alfredo; Cordon, O.

    2016-01-01

    Microgrids are sustainable solutions for electrification of rural zones that can make use of their local renewable resources. In this paper, we propose a new method for microgrid planning which includes the effect of the uncertainties of the renewable resources explicitly. Fuzzy interval models are

  6. Energy trading and pricing in microgrids with uncertain energy supply

    Ma, Kai; Hu, Shubing; Yang, Jie

    2017-01-01

    This paper studies an energy trading and pricing problem for microgrids with uncertain energy supply. The energy provider with the renewable energy (RE) generation (wind power) determines the energy purchase from the electricity markets and the pricing strategy for consumers to maximize its profi....... In particular, the uncertainty of the energy supply from the energy provider is considered. Simulation results show that the energy provider can obtain more profit using the proposed decision-making scheme.......This paper studies an energy trading and pricing problem for microgrids with uncertain energy supply. The energy provider with the renewable energy (RE) generation (wind power) determines the energy purchase from the electricity markets and the pricing strategy for consumers to maximize its profit...

  7. Optimization of joint energy micro-grid with cold storage

    Xu, Bin; Luo, Simin; Tian, Yan; Chen, Xianda; Xiong, Botao; Zhou, Bowen

    2018-02-01

    To accommodate distributed photovoltaic (PV) curtailment, to make full use of the joint energy micro-grid with cold storage, and to reduce the high operating costs, the economic dispatch of joint energy micro-grid load is particularly important. Considering the different prices during the peak and valley durations, an optimization model is established, which takes the minimum production costs and PV curtailment fluctuations as the objectives. Linear weighted sum method and genetic-taboo Particle Swarm Optimization (PSO) algorithm are used to solve the optimization model, to obtain optimal power supply output. Taking the garlic market in Henan as an example, the simulation results show that considering distributed PV and different prices in different time durations, the optimization strategies are able to reduce the operating costs and accommodate PV power efficiently.

  8. Microgrids in the Evolving Electricity Generation and DeliveryInfrastructure

    Marnay, Chris; Venkataramanan, Giri

    2006-02-01

    The legacy paradigm for electricity service in most of the electrified world today is based on the centralized generation-transmission-distribution infrastructure that evolved under a regulated environment. More recently, a quest for effective economic investments, responsive markets, and sensitivity to the availability of resources, has led to various degrees of deregulation and unbundling of services. In this context, a new paradigm is emerging wherein electricity generation is intimately embedded with the load in microgrids. Development and decay of the familiar macrogrid is discussed. Three salient features of microgrids are examined to suggest that cohabitation of micro and macro grids is desirable, and that overall energy efficiency can be increased, while power is delivered to loads at appropriate levels of quality.

  9. Guest Editorial Special Issue on Structured DC Microgrids

    Guerrero, Josep M.; Tan, Don F. D.

    2017-01-01

    With the development of dc coupled devices, such as photovoltaic generations, batteries, supercapacitors, LEDs, computers, and electronics equipment, low-voltage dc distribution networks, structured dc microgrids are emerging as a natural platform to integrate renewable energy sources. However...... in either series/parallel, forming a number of dc busses with different voltage levels. Recently, with the advance of new dc power technologies, several ongoing standards, alliances, and initiatives are bringing the possibility of developing future homes, offices, buildings, campuses, datacenters, ships......, satellites, aircrafts, and other electrical power systems to operate totally or dominantly in dc. Research is being carried out in both the system and component levels of modeling, control, and stability of structured dc microgrids. New high-efficiency topologies and protections are also key nontrivial...

  10. Aerodynamic load control strategy of wind turbine in microgrid

    Wang, Xiangming; Liu, Heshun; Chen, Yanfei

    2017-12-01

    A control strategy is proposed in the paper to optimize the aerodynamic load of the wind turbine in micro-grid. In grid-connection mode, the wind turbine adopts a new individual variable pitch control strategy. The pitch angle of the blade is rapidly given by the controller, and the pitch angle of each blade is fine tuned by the weight coefficient distributor. In islanding mode, according to the requirements of energy storage system, a given power tracking control method based on fuzzy PID control is proposed. Simulation result shows that this control strategy can effectively improve the axial aerodynamic load of the blade under rated wind speed in grid-connection mode, and ensure the smooth operation of the micro-grid in islanding mode.

  11. Decentralized Economic Dispatch Scheme With Online Power Reserve for Microgrids

    Nutkani, I. U.; Loh, Poh Chiang; Wang, P.

    2017-01-01

    Decentralized economic operation schemes have several advantages when compared with the traditional centralized management system for microgrids. Specifically, decentralized schemes are more flexible, less computationally intensive, and easier to implement without relying on communication...... costs, their power ratings, and other necessary constraints, before deciding the DG dispatch priorities and droop characteristics. The proposed scheme also allows online power reserve to be set and regulated within the microgrid. This, together with the generation cost saved, has been verified...... infrastructure. Economic operation of existing decentralized schemes is also usually achieved by either tuning the droop characteristics of distributed generators (DGs) or prioritizing their dispatch order. For the latter, an earlier scheme has tried to prioritize the DG dispatch based on their no...

  12. Research on Integrated Control of Microgrid Operation Mode

    Cheng, ZhiPing; Gao, JinFeng; Li, HangYu

    2018-03-01

    The mode switching control of microgrid is the focus of its system control. According to the characteristics of different control, an integrated control system is put forward according to the detecting voltage and frequency deviation after switching of microgrid operating mode. This control system employs master-slave and peer-to-peer control. Wind turbine and photovoltaic(PV) adopt P/Q control, so the maximum power output can be achieved. The energy storage will work under the droop control if the system is grid-connected. When the system is off-grid, whether to employ droop control or P/f control is determined by system status. The simulation has been done and the system performance can meet the requirement.

  13. Microgrid Reactive and Harmonic Power Sharing Using Enhanced Virtual Impedance

    He, Jinwei; Wei Li, Yun; Guerrero, Josep M.

    2013-01-01

    To address the load sharing problem in islanding microgrids, this paper proposes an improved approach which regulates the distributed generation (DG) unit interfacing virtual impedance at fundamental and selected harmonic frequencies. In contrast to the conventional virtual impedance control where...... only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedances at fundamental and harmonic frequencies are realized using DG line current and point of common coupling (PCC) voltage feed-forward terms, respectively. With this modification, the mismatched DG...... feeder impedances can be properly compensated, resulting in accurate reactive and harmonic power sharing at the same time. In addition, this paper shows that the microgrid PCC harmonic voltages can be mitigated by reducing the magnitude of DG unit equivalent harmonic impedance. Finally, an improved...

  14. Agent-based distributed hierarchical control of dc microgrid systems

    Meng, Lexuan; Vasquez, Juan Carlos; Guerrero, Josep M.

    2014-01-01

    In order to enable distributed control and management for microgrids, this paper explores the application of information consensus and local decisionmaking methods formulating an agent based distributed hierarchical control system. A droop controlled paralleled DC/DC converter system is taken as ....... Standard genetic algorithm is applied in each local control system in order to search for a global optimum. Hardware-in-Loop simulation results are shown to demonstrate the effectiveness of the method.......In order to enable distributed control and management for microgrids, this paper explores the application of information consensus and local decisionmaking methods formulating an agent based distributed hierarchical control system. A droop controlled paralleled DC/DC converter system is taken...... as a case study. The objective is to enhance the system efficiency by finding the optimal sharing ratio of load current. Virtual resistances in local control systems are taken as decision variables. Consensus algorithms are applied for global information discovery and local control systems coordination...

  15. Preparation of carbon-free TEM microgrids by metal sputtering

    Janbroers, S.; Kruijff, T.R. de; Xu, Q.; Kooyman, P.J.; Zandbergen, H.W.

    2009-01-01

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775 K under vacuum conditions.

  16. Preparation of carbon-free TEM microgrids by metal sputtering

    Janbroers, S., E-mail: stephan.janbroers@albemarle.com [Albemarle Catalysts B.V., Nieuwendammerkade 1-3, 1030 BE, Amsterdam (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Kruijff, T.R. de; Xu, Q. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Kooyman, P.J. [DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL, Delft (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Zandbergen, H.W. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2009-08-15

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775 K under vacuum conditions.

  17. Reliability evaluation of microgrid considering incentive-based demand response

    Huang, Ting-Cheng; Zhang, Yong-Jun

    2017-07-01

    Incentive-based demand response (IBDR) can guide customers to adjust their behaviour of electricity and curtail load actively. Meanwhile, distributed generation (DG) and energy storage system (ESS) can provide time for the implementation of IBDR. The paper focus on the reliability evaluation of microgrid considering IBDR. Firstly, the mechanism of IBDR and its impact on power supply reliability are analysed. Secondly, the IBDR dispatch model considering customer’s comprehensive assessment and the customer response model are developed. Thirdly, the reliability evaluation method considering IBDR based on Monte Carlo simulation is proposed. Finally, the validity of the above models and method is studied through numerical tests on modified RBTS Bus6 test system. Simulation results demonstrated that IBDR can improve the reliability of microgrid.

  18. Preparation of carbon-free TEM microgrids by metal sputtering.

    Janbroers, S; de Kruijff, T R; Xu, Q; Kooyman, P J; Zandbergen, H W

    2009-08-01

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775K under vacuum conditions.

  19. Model Predictive Control for Distributed Microgrid Battery Energy Storage Systems

    Morstyn, Thomas; Hredzak, Branislav; Aguilera, Ricardo P.

    2018-01-01

    , and converter current constraints to be addressed. In addition, nonlinear variations in the charge and discharge efficiencies of lithium ion batteries are analyzed and included in the control strategy. Real-time digital simulations were carried out for an islanded microgrid based on the IEEE 13 bus prototypical......This brief proposes a new convex model predictive control (MPC) strategy for dynamic optimal power flow between battery energy storage (ES) systems distributed in an ac microgrid. The proposed control strategy uses a new problem formulation, based on a linear $d$ – $q$ reference frame voltage...... feeder, with distributed battery ES systems and intermittent photovoltaic generation. It is shown that the proposed control strategy approaches the performance of a strategy based on nonconvex optimization, while reducing the required computation time by a factor of 1000, making it suitable for a real...

  20. Energy Sharing Framework for Microgrid-Powered Cellular Base Stations

    Farooq, Muhammad Junaid

    2017-02-07

    Cellular base stations (BSs) are increasingly becoming equipped with renewable energy generators to reduce operational expenditures and carbon footprint of wireless communications. Moreover, advancements in the traditional electricity grid allow two-way power flow and metering that enable the integration of distributed renewable energy generators at BS sites into a microgrid. In this paper, we develop an optimized energy management framework for microgrid-connected cellular BSs that are equipped with renewable energy generators and finite battery storage to minimize energy cost. The BSs share excess renewable energy with others to reduce the dependency on the conventional electricity grid. Three cases are investigated where the renewable energy generation is unknown, perfectly known, and partially known ahead of time. For the partially known case where only the statistics of renewable energy generation are available, stochastic programming is used to achieve a conservative solution. Results show the time varying energy management behaviour of the BSs and the effect of energy sharing between them.

  1. Microgrid Reliability Modeling and Battery Scheduling Using Stochastic Linear Programming

    Cardoso, Goncalo; Stadler, Michael; Siddiqui, Afzal; Marnay, Chris; DeForest, Nicholas; Barbosa-Povoa, Ana; Ferrao, Paulo

    2013-05-23

    This paper describes the introduction of stochastic linear programming into Operations DER-CAM, a tool used to obtain optimal operating schedules for a given microgrid under local economic and environmental conditions. This application follows previous work on optimal scheduling of a lithium-iron-phosphate battery given the output uncertainty of a 1 MW molten carbonate fuel cell. Both are in the Santa Rita Jail microgrid, located in Dublin, California. This fuel cell has proven unreliable, partially justifying the consideration of storage options. Several stochastic DER-CAM runs are executed to compare different scenarios to values obtained by a deterministic approach. Results indicate that using a stochastic approach provides a conservative yet more lucrative battery schedule. Lower expected energy bills result, given fuel cell outages, in potential savings exceeding 6percent.

  2. Dispatchable Renewable Energy Model for Microgrid Power System

    Chiou, Fred; Gentle, Jake P.; McJunkin, Timothy R.

    2017-04-01

    Over the years, many research projects have been performed and focused on finding out the effective ways to balance the power demands and supply on the utility grid. The causes of the imbalance could be the increasing demands from the end users, the loss of power generation (generators down), faults on the transmission lines, power tripped due to overload, and weather conditions, etc. An efficient Load Frequency Control (LFC) can assure the desired electricity quality provided to the residential, commercial and industrial end users. A simulation model is built in this project to investigate the contribution of the modeling of dispatchable energy such as solar energy, wind power, hydro power and energy storage to the balance of the microgrid power system. An analysis of simplified feedback control system with proportional, integral, and derivative (PID) controller was performed. The purpose of this research is to investigate a simulation model that achieves certain degree of the resilient control for the microgrid.

  3. A GPS-Based Decentralized Control Method for Islanded Microgrids

    Golsorkhi, Mohammad; Lu, Dylan; Guerrero, Josep M.

    2017-01-01

    Coordinated control of distributed energy resources (DER) is essential for the operation of islanded microgrids (MGs). Conventionally, such coordination is achieved by drooping the frequency of the reference voltage versus active (or reactive) power. The conventional droop method ensures synchron......Coordinated control of distributed energy resources (DER) is essential for the operation of islanded microgrids (MGs). Conventionally, such coordination is achieved by drooping the frequency of the reference voltage versus active (or reactive) power. The conventional droop method ensures......, GPS timing technology is utilized to synchronize the DERs to a common reference frame, rotating at nominal frequency. In addition, an adaptive Q-f droop controller is introduced as a backup to ensure stable operation during GPS signal interruptions. In the context of the common reference frame, even...

  4. Economic–environmental hierarchical frequency management of a droop-controlled islanded microgrid

    Rezaei, Navid; Kalantar, Mohsen

    2014-01-01

    Highlights: • Modeling the steady-state frequency of the droop-controlled microgrids. • Precise formulation the hierarchical control levels of islanded microgrids. • Economic–environmental frequency management using mixed-integer linear programming. • Proposing a novel objective function based on the microgrid daily frequency profile. • Scheduling primary and secondary control reserves using a stochastic optimization. - Abstract: This paper presents a novel energy management system (EMS) for a microgrid to enhance the power system security in a cost-effective manner. Small size of the islanded microgrids, high levels of intermittency and energy fluctuations, lower inertia potential of inverter-interfaced distributed energy resources (DERs) makes the frequency a vital factor in the microgrid energy management system that should be managed subject to the economic–environmental policies of the microgrid EMS. The proposed model is based on precise energy and reserve scheduling of the DERs in a droop-controlled islanded microgrid to manage the possible microgrid frequency excursions. The expected value of the microgrid frequency excursions stem from system power deviations is employed as a new objective function in this study, which is aimed to be minimized using a two stage stochastic mixed-integer linear programming method. In order to model the hierarchical control structure of the islanded microgrid, the frequency dependent behavior of the droop-controlled inverter-interfaced DERs is formulated thoroughly. The proposed model is applied to a typical microgrid test system. The primary and secondary frequency control reserves are appropriately scheduled over a 24 h period. A methodology based on the Monte-Carlo simulation strategy is adapted to generate some random scenarios corresponding to renewable generation variations, load consumption deviations and contingencies of line/unit outages. The generated scenarios are reduced and applied to the

  5. The Control Principles of the Wind Energy Based DC Microgrid

    Zaleskis, G.; Rankis, I.

    2018-04-01

    According to the strategical objectives of the use of the renewable energy sources, it is important to minimise energy consumption of conventional power grid by effective use of the renewable energy sources and provi-ding stable operation of the consumers. The main aim of research is to develop technical solutions that can provide effective operation of the wind generators in the small power DC microgrids, which also means wind energy conversion at as wider generator speed range as possible.

  6. Optimization of Microgrids at Military Remote Base Camps

    2017-12-01

    the four primary technology areas for 2016 was “energy storage technology for mobile electric micro-grid applications” [12]. 4 Figure 1.3. Typical...providing electrical power to a remote U.S. contingency base. The first program minimizes the total cost of electricity production and the second program...battlefield and at home are a high priority for the U.S. military. We present twomixed integer linear programs developed for amicrogrid providing electrical

  7. Experimental evaluation of voltage unbalance compensation in an islanded microgrid

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    In this paper, a method for voltage unbalance compensation in an islanded microgrid based on the proper control of distributed generators (DGs) interface converter is proposed. In this method, active and reactive power control loops are considered to control the power sharing among the DGs. Also......, a virtual impedance loop and voltage and current proportional-resonant controllers are included. Experimental results show the effectiveness of the proposed method for compensating voltage unbalance to an acceptable level....

  8. Evaluating business models for microgrids: Interactions of technology and policy

    Hanna, Ryan; Ghonima, Mohamed; Kleissl, Jan; Tynan, George; Victor, David G.

    2017-01-01

    Policy makers are increasingly focused on strategies to decentralize the electricity grid. We analyze the business model for one mode of decentralization—microgrids—and quantify the economics for self-supply of electricity and thermal energy and explicitly resolve technological as well as policy variables. We offer a tool, based on the Distributed Energy Resources Customer Adoption Model (DER-CAM) modeling framework, that determines the cost-minimal capacity and operation of distributed energy resources in a microgrid, and apply it in southern California to three “iconic” microgrid types which represent typical commercial adopters: a large commercial building, critical infrastructure, and campus. We find that optimal investment leads to some deployment of renewables but that natural gas technologies underpin the most robust business cases—due in part to relatively cheap gas and high electricity rates. This finding contrasts sharply with most policy advocacy, which has focused on the potentials for decentralization of the grid to encourage deployment of renewables. Decentralization could radically reduce customer energy costs, but without the right policy framework it could create large numbers of small decentralized sources of gas-based carbon emissions that will be difficult to control if policy makers want to achieve deep cuts in greenhouse gas emissions. - Highlights: • We offer a modeling tool to study technology and policy variables for microgrids. • We construct comprehensive load profiles for three likely adopters of microgrids. • Investment in natural gas generators is key to enabling business models. • Solar PV and storage are optimal but as supplements to gas generation. • Business models are highly robust to sensitivity in technology and policy variables.

  9. Distributed Energy Resources and Dynamic Microgrid: An Integrated Assessment

    Shang, Duo Rick

    The overall goal of this thesis is to improve understanding in terms of the benefit of DERs to both utility and to electricity end-users when integrated in power distribution system. To achieve this goal, a series of two studies was conducted to assess the value of DERs when integrated with new power paradigms. First, the arbitrage value of DERs was examined in markets with time-variant electricity pricing rates (e.g., time of use, real time pricing) under a smart grid distribution paradigm. This study uses a stochastic optimization model to estimate the potential profit from electricity price arbitrage over a five-year period. The optimization process involves two types of PHEVs (PHEV-10, and PHEV-40) under three scenarios with different assumptions on technology performance, electricity market and PHEV owner types. The simulation results indicate that expected arbitrage profit is not a viable option to engage PHEVs in dispatching and in providing ancillary services without more favorable policy and PHEV battery technologies. Subsidy or change in electricity tariff or both are needed. Second, it examined the concept of dynamic microgrid as a measure to improve distribution resilience, and estimates the prices of this emerging service. An economic load dispatch (ELD) model is developed to estimate the market-clearing price in a hypothetical community with single bid auction electricity market. The results show that the electricity market clearing price on the dynamic microgrid is predominantly decided by power output and cost of electricity of each type of DGs. At circumstances where CHP is the only source, the electricity market clearing price in the island is even cheaper than the on-grid electricity price at normal times. Integration of PHEVs in the dynamic microgrid will increase electricity market clearing prices. It demonstrates that dynamic microgrid is an economically viable alternative to enhance grid resilience.

  10. Control Strategy for Microgrid Inverter under Unbalanced Grid Voltage Conditions

    Guo, Xiaoqiang; Liu, Wenzhao; Zhang, X.

    2014-01-01

    This paper presents the theoretical analysis of the inherent reason of current harmonic and power oscillation phenomena in case of operating the microgrid inverter under unbalanced grid voltage conditions. In order to flexibly control the current harmonic and power oscillation, a new stationary...... inverter. Finally, the performance evaluation tests are carried out under unbalanced grid voltage conditions. Results verify the effectiveness of the propose method....

  11. Optimal Sizing and Sitting of Smart Microgrid Units under Pool Electricity Market

    Hakimi, Seyed Mehdi; Hajizadeh, Amin

    2017-01-01

    , reliability cost, power loss cost and selling and buying electricity cost. The new idea of this paper is the investigation of pool electricity market aspects in optimization of smart microgrid. On the other hand, cost minimization of smart microgrid is related to their bidding strategies. Therefore two...... different optimization tools are considered. First, a game-theoretical (GT) model has been used for bidding strategy of smart microgrid as a price-maker, in a long-term electricity market. Secondly, a particle swarm optimization (PSO) algorithm is employed to obtain the best cost value of smart microgrids...... construction. This study was performed for the Ekbatan residential complex in Tehran, Iran. It has three smart microgrids consist of renewable energy resources. They participate in a long-term electricity market as a price maker. The results show that the proposed method is more effective and has lower cost...

  12. Autonomous Operation of Hybrid Microgrid with AC and DC Sub-Grids

    Loh, Poh Chiang; Blaabjerg, Frede

    2011-01-01

    the power flow among all the sources distributed throughout the two types of sub-grids, which certainly is tougher than previous efforts developed for only either ac or dc microgrid. This wider scope of control has not yet been investigated, and would certainly rely on the coordinated operation of dc...... sources, ac sources and interlinking converters. Suitable control and normalization schemes are therefore developed for controlling them with results presented for showing the overall performance of the hybrid microgrid.......This paper investigates on the active and reactive power sharing of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac sub-grids, interconnected by power electronic interfaces. The main challenge here is to manage...

  13. Stability Analysis for Isolated AC Microgrids Based on PV-Active Generators

    Aldana, Nelson Leonardo Diaz; Coelho, Ernane A. A.; Quintero, Juan Carlos Vasquez

    2015-01-01

    The current trend in isolated microgrids is oriented to distributed renewable energy generators, such as photovoltaic (PV) generators and their corresponding distributed energy storage systems (ESS) as an unit denoted as active generator (PV+ESS). In an isolated microgrid, every distributed...... for all the distributed generators. In particular, ESS’s based on batteries require at least two different mode of charge. As consequence, the topological operation mode of the microgrid is affected by the changes of the operation mode of each distributed generator. Typically, droop control loops are used...... for interconnecting several different distributed generators in parallel to a common bus, whose parameters determine the stability and damping of the microgrid operation. In this paper, a small-signal stability analysis is applied to an isolated AC microgrid composed of (PV+ESS) active generators, regarding three...

  14. Design of Energy Storage Management System Based on FPGA in Micro-Grid

    Liang, Yafeng; Wang, Yanping; Han, Dexiao

    2018-01-01

    Energy storage system is the core to maintain the stable operation of smart micro-grid. Aiming at the existing problems of the energy storage management system in the micro-grid such as Low fault tolerance, easy to cause fluctuations in micro-grid, a new intelligent battery management system based on field programmable gate array is proposed : taking advantage of FPGA to combine the battery management system with the intelligent micro-grid control strategy. Finally, aiming at the problem that during estimation of battery charge State by neural network, initialization of weights and thresholds are not accurate leading to large errors in prediction results, the genetic algorithm is proposed to optimize the neural network method, and the experimental simulation is carried out. The experimental results show that the algorithm has high precision and provides guarantee for the stable operation of micro-grid.

  15. Simulation For Synchronization Of A Micro-Grid With Three-Phase Systems

    Mohammad Jafari Far

    2015-08-01

    Full Text Available Abstract today due to the high reliability of the micro-grids they have developed significantly. They have two states of operation the island state and connection to the main grid. Under certain circumstances the micro-grid is connected to or disconnected from the network. Synchronization of a micro-grid with the network must be done when its voltage is synchronized with the voltage in the main grid. Phase lock loops are responsible to identify the voltage phase of the micro-gird and the main grid and when these two voltages are in the same phase they connect the micro-grid to the main grid. In this research the connection of a micro-grid to the main grid in the two phases of synchronous and asynchronous voltage is simulated and investigated.

  16. A Hierarchical Transactive Energy Management System for Energy Sharing in Residential Microgrids

    Most Nahida Akter

    2017-12-01

    Full Text Available This paper presents an analytical framework to develop a hierarchical energy management system (EMS for energy sharing among neighbouring households in residential microgrids. The houses in residential microgrids are categorized into three different types, traditional, proactive and enthusiastic, based on the inclusion of solar photovoltaic (PV systems and battery energy storage systems (BESSs. Each of these three houses has an individual EMS, which is defined as the primary EMS. Two other EMSs (secondary and tertiary are also considered in the proposed hierarchical energy management framework for the purpose of effective energy sharing. The intelligences of each EMS are presented in this paper for the purpose of energy sharing in a residential microgrid along with the priorities. The effectiveness of the proposed hierarchical framework is evaluated on a residential microgrid in Australia. The analytical results clearly reflect that the proposed scheme effectively and efficiently shares the energy among neighbouring houses in a residential microgrid.

  17. Study of the integration of distributed generation systems in the grid: application in micro-grids

    Gaztanaga Arantzamendi, H.

    2006-12-01

    The present PhD deals with an original micro-grid concept and its application as a Renewable Energy Source's (RES) grid integration scheme. This micro-grid is composed of RES generators as well as support systems that incorporate additional functionalities in order to improve RES integration into the grid. According to this concept, two practical micro-grid applications have been studied in detail: a residential micro-grid and a wind farm supported by DFACTS systems (STATCOM and DVR). In both applications, the control structures which are implemented at different levels and applied to the different micro-grid elements have been developed, analyzed by means of off-line simulations and finally validated in real-time conditions with physical reduced-scale prototypes. (author)

  18. Optimal Protection Coordination for Microgrid under Different Operating Modes

    Ming-Ta Yang

    2013-01-01

    Full Text Available Significant consequences result when a microgrid is connected to a distribution system. This study discusses the impacts of bolted three-phase faults and bolted single line-to-ground faults on the protection coordination of a distribution system connected by a microgrid which operates in utility-only mode or in grid-connected mode. The power system simulation software is used to build the test system. The linear programming method is applied to optimize the coordination of relays, and the relays coordination simulation software is used to verify if the coordination time intervals (CTIs of the primary/backup relay pairs are adequate. In addition, this study also proposes a relays protection coordination strategy when the microgrid operates in islanding mode during a utility power outage. Because conventional CO/LCO relays are not capable of detecting high impedance fault, intelligent electrical device (IED combined with wavelet transformer and neural network is proposed to accurately detect high impedance fault and identify the fault phase.

  19. Online management genetic algorithms of microgrid for residential application

    Mohamed, Faisal A.; Koivo, Heikki N.

    2012-01-01

    Highlights: ► We determine the optimal Generation optimization scheme of Microgrid. ► We employ Genetic Algorithm to the environmental/economic problem of the MG. ► We captured the optimal behavior of the MG with high accuracy even with new six different cases. - Abstract: This paper proposes a generalized formulation to determine the optimal operating strategy and cost optimization scheme for a MicroGrid (MG) for residential application. Genetic Algorithm is applied to the environmental/economic problem of the MG. The proposed problem is formulated as a nonlinear constrained MO optimization problem. Prior to the optimization of the microgrid itself, models for the system components are determined using real data. The proposed cost function takes into consideration the costs of the emissions, NOx, SO 2 , and CO 2 , start up costs, as well as the operation and maintenance costs. The MG considered in this paper consists of a wind turbine, a microturbine, a diesel generator, a photovoltaic array, a fuel cell, and a battery storage. The optimization is aimed at minimizing the cost function of the system while constraining it to meet the costumer demand and safety of the system. We also add a daily income and outgo from sale or purchased power. The results demonstrate the efficiency of the proposed approach to satisfy the load and to reduce the cost and the emissions. The comparison with other techniques demonstrates the superiority of the proposed approach and confirms its potential to solve the problem.

  20. A robust optimization approach for energy generation scheduling in microgrids

    Wang, Ran; Wang, Ping; Xiao, Gaoxi

    2015-01-01

    Highlights: • A new uncertainty model is proposed for better describing unstable energy demands. • An optimization problem is formulated to minimize the cost of microgrid operations. • Robust optimization algorithms are developed to transform and solve the problem. • The proposed scheme can prominently reduce energy expenses. • Numerical results provide useful insights for future investment policy making. - Abstract: In this paper, a cost minimization problem is formulated to intelligently schedule energy generations for microgrids equipped with unstable renewable sources and combined heat and power (CHP) generators. In such systems, the fluctuant net demands (i.e., the electricity demands not balanced by renewable energies) and heat demands impose unprecedented challenges. To cope with the uncertainty nature of net demand and heat demand, a new flexible uncertainty model is developed. Specifically, we introduce reference distributions according to predictions and field measurements and then define uncertainty sets to confine net and heat demands. The model allows the net demand and heat demand distributions to fluctuate around their reference distributions. Another difficulty existing in this problem is the indeterminate electricity market prices. We develop chance constraint approximations and robust optimization approaches to firstly transform and then solve the prime problem. Numerical results based on real-world data evaluate the impacts of different parameters. It is shown that our energy generation scheduling strategy performs well and the integration of combined heat and power (CHP) generators effectively reduces the system expenditure. Our research also helps shed some illuminations on the investment policy making for microgrids.

  1. Renewable Energy Resources With Smart Microgrid Model In India

    Manikant Kumar

    2015-08-01

    Full Text Available Along with the development of civilization is increasing energy consumption. Due to which India is facing an energy crisis. It is estimated that global energy demand will double in 2030. India Trhurga other developing countries will face a crisis. Returning to the problem Fall growth of renewable energy resources will increase. Even for electricity generation from renewable sources. Naturally replenished renewable energy such as sunlight wind rain tides and geothermal heat as will have to depend on natural resources. High energy demand and environmental concerns in the papers smart microgrid is forced to change the existing power grid. This paper dynamic demand response and smart microgrid for residential and industrial consumption in the context of renewable energy production including the proposed management approach. The objectives of this research renewable energy resources with a smart microgrid has played an important role. Power system in rural areas in India to meet growing energy demand. The model deployed PLC networks data management system sensors Switchgears Transformers and other utility tools to integrate Smart Grid Smart homes are used together. Analytical results Residential renewable energy generation and smart meters show the effectiveness of the proposed system to optimize control of the electrical grid and is designed to improve energy conservation.

  2. A Domestic Microgrid with Optimized Home Energy Management System

    Zafar Iqbal

    2018-04-01

    Full Text Available Microgrid is a community-based power generation and distribution system that interconnects smart homes with renewable energy sources (RESs. Microgrid efficiently and economically generates power for electricity consumers and operates in both islanded and grid-connected modes. In this study, we proposed optimization schemes for reducing electricity cost and minimizing peak to average ratio (PAR with maximum user comfort (UC in a smart home. We considered a grid-connected microgrid for electricity generation which consists of wind turbine and photovoltaic (PV panel. First, the problem was mathematically formulated through multiple knapsack problem (MKP then solved by existing heuristic techniques: grey wolf optimization (GWO, binary particle swarm optimization (BPSO, genetic algorithm (GA and wind-driven optimization (WDO. Furthermore, we also proposed three hybrid schemes for electric cost and PAR reduction: (1 hybrid of GA and WDO named WDGA; (2 hybrid of WDO and GWO named WDGWO; and (3 WBPSO, which is the hybrid of BPSO and WDO. In addition, a battery bank system (BBS was also integrated to make our proposed schemes more cost-efficient and reliable, and to ensure stable grid operation. Finally, simulations were performed to verify our proposed schemes. Results show that our proposed scheme efficiently minimizes the electricity cost and PAR. Moreover, our proposed techniques, WDGA, WDGWO and WBPSO, outperform the existing heuristic techniques.

  3. Smart Microgrid Energy Management Using a Novel Artificial Shark Optimization

    Pawan Singh

    2017-01-01

    Full Text Available At present, renewable energy sources (RESs integration using microgrid (MG technology is of great importance for demand side management. Optimization of MG provides enhanced generation from RES at minimum operation cost. The microgrid optimization problem involves a large number of variables and constraints; therefore, it is complex in nature and various existing algorithms are unable to handle them efficiently. This paper proposed an artificial shark optimization (ASO method to remove the limitation of existing algorithms for solving the economical operation problem of MG. The ASO algorithm is motivated by the sound sensing capability of sharks, which they use for hunting. Further, the intermittent nature of renewable energy sources is managed by utilizing battery energy storage (BES. BES has several benefits. However, all these benefits are limited to a certain fixed area due to the stationary nature of the BES system. The latest technologies, such as electric vehicle technologies (EVTs, provide all benefits of BES along with mobility to support the variable system demands. Therefore, in this work, EVTs incorporated grid connected smart microgrid (SMG system is introduced. Additionally, a comparative study is provided, which shows that the ASO performs relatively better than the existing techniques.

  4. The optimal scheduling of decentralised co-generation plants in microgrids; Optimale Einsatzplanung von Kraft-Waerme-Kopplungsanlagen in Microgrids

    Gunkel, David [TU Dresden (Germany). Lehrstuhl fuer Energiewirtschaft; Hess, Tobias; Schegner, Peter [TU Dresden (Germany). Inst. fuer Elektrische Energieversorgung und Hochspannungstechnik

    2011-07-01

    The daily operational scheduling of decentralised unit is an important optimization task of power systems. This proceeding deals with planning of small scaled co-generation power units for district heating in a microgrid. This power system can be mathematically formulated and solved by an optimization algorithm. The solution process consists of a unit commitment and dispatch. The starting unit commitment is characterised by a mixed integer nonlinear problem defining the on-off-state of all units. Subsequently, the dispatch distributes the generation requirements to every committed unit considering thermal demand. The dispatching is based on a mixed integer linear problem. Additionally, it presents a way for flexible reducing the outage reserve related to the operational condition. The given microgrid operates in an islanding mode. The method can also be applied in a grid connected model considering the possible requirements of a grid operator. (orig.)

  5. A feasibility study of microgrids for reducing energy use and GHG emissions in an industrial application

    Li, Mengyu; Zhang, Xiongwen; Li, Guojun; Jiang, Chaoyang

    2016-01-01

    Highlights: • A life cycle assessment is conducted on the microgrids for an industry application. • The effect of renewable energy on the LCA performances of microgrids is illustrated. • The minimal life cycle energy use and GHG emissions of microgrids are evaluated. • The LCA of different pathways for electricity, heat and hydrogen are presented. - Abstract: Microgrids provide a new energy paradigm with the benefits of higher energy supply reliability, lower greenhouse gas (GHG) emissions through a higher penetration of renewable sources, higher energy efficiencies through the use of local waste heat and the avoidance of losses in transmission and distribution. This study reports a life cycle assessment (LCA) of microgrids for an industry application of an ammonia plant in central Inner Mongolia, China. The life cycle energy use and GHG emissions of the microgrids are evaluated and compared to the existing fossil fuel-based energy system. The electricity, heat and hydrogen fuel loads of the ammonia plant are all modelled in the study. An optimization model is developed to estimate the minimum life cycle energy use and GHG emissions with the microgrids under three scenarios (natural gas (NG)-based, optimized, and maximum renewable energy microgrids). The results indicate that the use of wind and solar in the NG-based microgrid can only slightly reduce the energy use and GHG emissions. If there are no land area limitations on the deployment of solar and wind power, the maximum renewable energy microgrid offers significant reductions of fossil fuel energy of up to 56.9% and GHG emissions reductions of up to 66.3% compared to the existing energy system.

  6. 2010 CERT Research Report

    2011-09-01

    extensive and expensive rework before implementation. Analysis of catastrophe helps us to see how complex, multi-system, multi-organizational...Cyber Security Science of Cyber Security, published by JASON , an independent scientific advisory group that provides consulting services to the U.S...Ed Desautels Lisa Gardner Alexa Huth Mindi McDowell Amanda Parente Pennie Walters Contributing Team Members Michelle Fried Lisa Marino Design David

  7. Voltage Control Scheme with Distributed Generation and Grid Connected Converter in a DC Microgrid

    Jong-Chan Choi

    2014-10-01

    Full Text Available Direct Current (DC microgrids are expected to become larger due to the rapid growth of DC energy sources and power loads. As the scale of the system expends, the importance of voltage control will be increased to operate power systems stably. Many studies have been performed on voltage control methods in a DC microgrid, but most of them focused only on a small scale microgrid, such as a building microgrid. Therefore, a new control method is needed for a middle or large scale DC microgrid. This paper analyzes voltage drop problems in a large DC microgrid and proposes a cooperative voltage control scheme with a distributed generator (DG and a grid connected converter (GCC. For the voltage control with DGs, their location and capacity should be considered for economic operation in the systems. Accordingly, an optimal DG allocation algorithm is proposed to minimize the capacity of a DG for voltage control in DC microgrids. The proposed methods are verified with typical load types by a simulation using MATLAB and PSCAD/EMTDC.

  8. Multi-Agent System-Based Microgrid Operation Strategy for Demand Response

    Hee-Jun Cha

    2015-12-01

    Full Text Available The microgrid and demand response (DR are important technologies for future power grids. Among the variety of microgrid operations, the multi-agent system (MAS has attracted considerable attention. In a microgrid with MAS, the agents installed on the microgrid components operate optimally by communicating with each other. This paper proposes an operation algorithm for the individual agents of a test microgrid that consists of a battery energy storage system (BESS and an intelligent load. A microgrid central controller to manage the microgrid can exchange information with each agent. The BESS agent performs scheduling for maximum benefit in response to the electricity price and BESS state of charge (SOC through a fuzzy system. The intelligent load agent assumes that the industrial load performs scheduling for maximum benefit by calculating the hourly production cost. The agent operation algorithm includes a scheduling algorithm using day-ahead pricing in the DR program and a real-time operation algorithm for emergency situations using emergency demand response (EDR. The proposed algorithm and operation strategy were implemented both by a hardware-in-the-loop simulation test using OPAL-RT and an actual hardware test by connecting a new distribution simulator.

  9. Hierarchical Agent-Based Integrated Modelling Approach for Microgrids with Adoption of EVs and HRES

    Peng Han

    2014-01-01

    Full Text Available The large adoption of electric vehicles (EVs, hybrid renewable energy systems (HRESs, and the increasing of the loads shall bring significant challenges to the microgrid. The methodology to model microgrid with high EVs and HRESs penetrations is the key to EVs adoption assessment and optimized HRESs deployment. However, considering the complex interactions of the microgrid containing massive EVs and HRESs, any previous single modelling approaches are insufficient. Therefore in this paper, the methodology named Hierarchical Agent-based Integrated Modelling Approach (HAIMA is proposed. With the effective integration of the agent-based modelling with other advanced modelling approaches, the proposed approach theoretically contributes to a new microgrid model hierarchically constituted by microgrid management layer, component layer, and event layer. Then the HAIMA further links the key parameters and interconnects them to achieve the interactions of the whole model. Furthermore, HAIMA practically contributes to a comprehensive microgrid operation system, through which the assessment of the proposed model and the impact of the EVs adoption are achieved. Simulations show that the proposed HAIMA methodology will be beneficial for the microgrid study and EV’s operation assessment and shall be further utilized for the energy management, electricity consumption prediction, the EV scheduling control, and HRES deployment optimization.

  10. Optimal Design and Real Time Implementation of Autonomous Microgrid Including Active Load

    Mohamed A. Hassan

    2018-05-01

    Full Text Available Controller gains and power-sharing parameters are the main parameters affect the dynamic performance of the microgrid. Considering an active load to the autonomous microgrid, the stability problem will be more involved. In this paper, the active load effect on microgrid dynamic stability is explored. An autonomous microgrid including three inverter-based distributed generations (DGs with an active load is modeled and the associated controllers are designed. Controller gains of the inverters and active load as well as Phase Locked Loop (PLL parameters are optimally tuned to guarantee overall system stability. A weighted objective function is proposed to minimize the error in both measured active power and DC voltage based on time-domain simulations. Different AC and DC disturbances are applied to verify and assess the effectiveness of the proposed control strategy. The results demonstrate the potential of the proposed controller to enhance the microgrid stability and to provide efficient damping characteristics. Additionally, the proposed controller is compared with the literature to demonstrate its superiority. Finally, the microgrid considered has been established and implemented on real time digital simulator (RTDS. The experimental results validate the simulation results and approve the effectiveness of the proposed controllers to enrich the stability of the considered microgrid.

  11. Awareness On Microgrids And Various Protection Issues To Overcome In It

    Rachna Verma

    2015-05-01

    Full Text Available ABSTRACT As we know India faces problem of Power blackout every year due to the overloading on the main electrical grid. To avoid the above problem Microgrids are the best solution. Basically Microgrids are the small version of electrical grid. They are independent power system. Microgrids can be connected with renewable energy sources such as solar and wind. The use of renewable energy introduces the need of various storing devices and supplies it whenever required. Microgrids can provide wide range of applications in buildings military camps and corporateacademic campuses etc. They can have efficient and effective provision of electricity to off-grid areas as well as keep the lights on in times of crisis for critical applications like hospital. Though Microgrids being so advantageous it has several technical challenging issues to overcome i.e. voltage and frequency control islanding and its protection in Microgrids. This paper discusses the overview of Microgrids and issue to overcome in it-its Protection.

  12. Modelling high level system design and unit commitment for a microgrid

    Hawkes, A.D. [Centre for Energy Policy and Technology, Imperial College London, London SW7 2AZ (United Kingdom); Leach, M.A. [Centre for Environmental Strategy, Faculty of Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2009-07-15

    This article develops a linear programming cost minimisation model for the high level system design and corresponding unit commitment of generators and storage within a microgrid; a set of energy resources working co-operatively to create a cost effective, reliable and environmentally friendly energy provision system. Previous work in this area is used as a basis for formulation of a new approach to this problem, with particular emphasis on why a microgrid is different to centralised generation or other grid-connected decentralised energy resources. Specifically, the model explicitly defines the amount of time that the microgrid would be expected to operate autonomously, and restricts flow of heat between microgrid participants to defined cases. The model developed is applied to a set of United Kingdom commercial load profiles, under best current estimates of energy prices and technology capital costs, to determine investment attractiveness of the microgrid. Sensitivity analysis of results to variations in energy prices is performed. The results broadly indicate that a microgrid can offer an economic proposition, although it is necessarily slightly more expensive than regular grid-connected decentralised generation. The analysis results have raised important questions regarding a fair method for settlement between microgrid participants, and game theory has been identified as a suitable tool to analyse aspects of this situation. (author)

  13. Voltage stability in low voltage microgrids in aspects of active and reactive power demand

    Parol Mirosław

    2016-03-01

    Full Text Available Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.

  14. Modelling high level system design and unit commitment for a microgrid

    Hawkes, A.D.; Leach, M.A.

    2009-01-01

    This article develops a linear programming cost minimisation model for the high level system design and corresponding unit commitment of generators and storage within a microgrid; a set of energy resources working co-operatively to create a cost effective, reliable and environmentally friendly energy provision system. Previous work in this area is used as a basis for formulation of a new approach to this problem, with particular emphasis on why a microgrid is different to centralised generation or other grid-connected decentralised energy resources. Specifically, the model explicitly defines the amount of time that the microgrid would be expected to operate autonomously, and restricts flow of heat between microgrid participants to defined cases. The model developed is applied to a set of United Kingdom commercial load profiles, under best current estimates of energy prices and technology capital costs, to determine investment attractiveness of the microgrid. Sensitivity analysis of results to variations in energy prices is performed. The results broadly indicate that a microgrid can offer an economic proposition, although it is necessarily slightly more expensive than regular grid-connected decentralised generation. The analysis results have raised important questions regarding a fair method for settlement between microgrid participants, and game theory has been identified as a suitable tool to analyse aspects of this situation. (author)

  15. Application of microgrids in providing ancillary services to the utility grid

    Majzoobi, Alireza; Khodaei, Amin

    2017-01-01

    A microgrid optimal scheduling model is developed in this paper to demonstrate microgrid's capability in offering ancillary services to the utility grid. The application of localized ancillary services is of significant importance to grid operators as the growing proliferation of distributed renewable energy resources, mainly solar generation, is causing major technical challenges in supply-load balance. The proposed microgrid optimal scheduling model coordinates the microgrid net load with the aggregated consumers/prosumers net load in its connected distribution feeder to capture both inter-hour and intra-hour net load variations. In particular, net load variations for three various time resolutions are considered, including hourly ramping, 10-min based load following, and 1-min based frequency regulation. Numerical simulations on a test distribution feeder with one microgrid and several consumers/prosumers indicate the effectiveness of the proposed model and the viability of the microgrid application in supporting grid operation. - Highlights: • Microgrid optimal scheduling for providing ancillary services to the utility grid. • Local management and mitigation of distribution net load variations. • Offering various support services: ramping, load following, frequency regulation. • Proven effectiveness and accuracy in capturing net load variations.

  16. Supply and Demand Control of Distributed Generators in a Microgrid for New Energy

    Shimakage, Toyonari; Sumita, Jiro; Uchiyama, Noriyuki; Kato, Takeyoshi; Suzuoki, Yasuo

    We report the operational results of distributed generators (DGs) in a microgrid and present the effects after incorporating photovoltaic power generation (PV) systems into the microgrid for electric power system. The microgrid was constructed at the EXPO 2005 Aichi site as part of a demonstration promoted by NEDO. A solution is needed to problems where instability in the DGs that utilize natural energy such as solar light and wind force negatively influence existing electric power systems. So, we developed energy control system and controlled DGs output to reduce the fluctuation at the grid connected point caused by PV system's instability output. Our microgrid consists of DGs such as PV systems, fuel cells, and NaS batteries, and these DGs are controlled by an energy control system. We verified practical effectiveness of the installing the microgrid as follows. (1) 99.5% of the power imbalance in the supply and demand over 30 minutes was within a range of ±3% under normal operating conditions, (2) the microgrid contributes to the load leveling, (3) energy control system smoothes the power flow fluctuation of PV system output at the grid connected point, (4) in the future, installing a microgrid will help reduce the additional LFC (Load Frequency Control) capacity.

  17. Microgrid energy management in grid-connected and islanding modes based on SVC

    Gabbar, Hossam A.; Abdelsalam, Abdelazeem A.

    2014-01-01

    Highlights: • SVC is used to enhance the performance of a microgrid (MG). • MG performance is measured by some key performance indicators (KPIs). • KPIs comprise power loss, voltage deviation, power factor, THD and v/f deviation. • The microgrid is simulated in grid-connected and islanded modes. • Results show SVC stabilizes voltage, reduce losses and THD and enhance power factor. - Abstract: Microgrids are small scale energy grids that can provide adequate energy supply to cover regional demand by integrating renewable energy generation and storage technologies. This paper develops a high performance dynamic model of a microgrid system comprising a wind turbine, a PV, a fuel cell, a micro gas turbine generator, an energy storage, electric loads with variable load profile and flexible AC transmission system (FACTS) devices. The FACTS devices based on static VAR compensators have been employed as a supervisory controller. Key performance indicators such as microgrid power losses, buses voltage deviations, buses power factor, buses voltage total harmonic distortion and voltage-frequency deviation are used to evaluate the performance of this microgrid in grid-connected and islanding modes. The results obtained from the Matlab/Simulink environment show that the proposed microgrid design with SVC has the ability to meet its special requirements such as bus voltages stabilization, reduction of feeder losses, power factor enhancement and mitigation of total harmonic distortion using SVC in grid-connected and islanding modes

  18. Joint energy demand and thermal comfort optimization in photovoltaic-equipped interconnected microgrids

    Baldi, Simone; Karagevrekis, Athanasios; Michailidis, Iakovos T.; Kosmatopoulos, Elias B.

    2015-01-01

    Highlights: • Energy efficient operation of photovoltaic-equipped interconnected microgrids. • Optimized energy demand for a block of heterogeneous buildings with different sizes. • Multiobjective optimization: matching demand and supply taking into account thermal comfort. • Intelligent control mechanism for heating, ventilating, and air conditioning units. • Optimization of energy consumption and thermal comfort at the aggregate microgrid level. - Abstract: Electrical smart microgrids equipped with small-scale renewable-energy generation systems are emerging progressively as an alternative or an enhancement to the central electrical grid: due to the intermittent nature of the renewable energy sources, appropriate algorithms are required to integrate these two typologies of grids and, in particular, to perform efficiently dynamic energy demand and distributed generation management, while guaranteeing satisfactory thermal comfort for the occupants. This paper presents a novel control algorithm for joint energy demand and thermal comfort optimization in photovoltaic-equipped interconnected microgrids. Energy demand shaping is achieved via an intelligent control mechanism for heating, ventilating, and air conditioning units. The intelligent control mechanism takes into account the available solar energy, the building dynamics and the thermal comfort of the buildings’ occupants. The control design is accomplished in a simulation-based fashion using an energy simulation model, developed in EnergyPlus, of an interconnected microgrid. Rather than focusing only on how each building behaves individually, the optimization algorithm employs a central controller that allows interaction among the buildings of the microgrid. The control objective is to optimize the aggregate microgrid performance. Simulation results demonstrate that the optimization algorithm efficiently integrates the microgrid with the photovoltaic system that provides free electric energy: in

  19. Grid impedance estimation based hybrid islanding detection method for AC microgrids

    Ghzaiel, Walid; Jebali-Ben Ghorbal, Manel; Slama-Belkhodja, Ilhem

    2017-01-01

    This paper focuses on a hybrid islanding detection algorithm for parallel-inverters-based microgrids. The proposed algorithm is implemented on the unit ensuring the control of the intelligent bypass switch connecting or disconnecting the microgrid from the utility. This method employs a grid...... to avoid interactions with other units. The selected inverter will be the one closest to the controllable distributed generation system or to a healthy grid side in case of meshed microgrid with multiple-grid connections. The detection algorithm is applied to quickly detect the resonance phenomena, so...

  20. Single-Phase Microgrid with Seamless Transition Capabilities between Modes of Operation

    Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril

    2015-01-01

    with the secondary control loops that are used to synchronize the microgrid as a single unit to the grid. Simulation results are given that show the seamless transitions between the two modes without any disconnection times for the CC-VSIs and VC-VSIs connected to the microgrid.......Microgrids are an effective way to increase the penetration of DG into the grid. They are capable of operating either in grid-connected or in islanded mode thereby increasing the supply reliability for the end user. This paper focuses on achieving seamless transitions from islanded to grid-connected...

  1. Optimal Sizing and Performance Evaluation of a Renewable Energy Based Microgrid in Future Seaports

    Baizura Binti Ahamad, Nor; Othman @ Marzuki, Muzaidi Bin; Quintero, Juan Carlos Vasquez

    2018-01-01

    This paper presents the optimal design and specifies the dimension, energy planning and evaluates the performance of a microgrid to supply the electricity to the load by using integrated microgrid. The integrated system consists of PV, wind turbine and a battery for grid-connected. This paper also...... analyzes the performance of the designed system based on seaport located in Copenhagen, Denmark as a case study. The analysis is performed by using Hybrid Optimization Model for Electric Renewables (HOMER) software which includes optimization and sensitivity analysis result. The simulation result indicates...... that the implementation of microgrid technologies would be a convenient solution to supply the electricity to the load application (shipboard)...

  2. Distributed Secondary Control for Islanded MicroGrids - A Novel Approach

    Shafiee, Qobad; Guerrero, Josep M.; Vasquez, Juan Carlos

    2014-01-01

    This paper presents a novel approach to conceive the secondary control in droop-controlled MicroGrids. The conventional approach is based on restoring the frequency and amplitude deviations produced by the local droop controllers by using a MicroGrid Central Controller (MGCC). A distributed...... networked control system is used in order to implement a distributed secondary control (DSC) thus avoiding its implementation in MGCC. The proposed approach is not only able to restore frequency and voltage of the MicroGrid but also ensures reactive power sharing. The distributed secondary control does...

  3. Simulation For Synchronization Of A Micro-Grid With Three-Phase Systems

    Mohammad Jafari Far

    2015-01-01

    Abstract today due to the high reliability of the micro-grids they have developed significantly. They have two states of operation the island state and connection to the main grid. Under certain circumstances the micro-grid is connected to or disconnected from the network. Synchronization of a micro-grid with the network must be done when its voltage is synchronized with the voltage in the main grid. Phase lock loops are responsible to identify the voltage phase of the micro-gird and the main...

  4. Application of cloud computing in power routing for clusters of microgrids using oblivious network routing algorithm

    Amini, M. Hadi; Broojeni, Kianoosh G.; Dragicevic, Tomislav

    2017-01-01

    of microgrid while preventing congestion as well as minimizing the power loss. Then, we present a two-layer simulation platform which considers both communication layer and physical layer of the microgrids' cluster. In order to improve the security of communication network, we perform the computations...... regarding the oblivious power routing via a cloud-based network. The proposed framework can be used for further studies that deal with the real-time simulation of the clusters of microgrids. In order to validate the effectiveness of the proposed framework, we implement our proposed oblivious routing scheme...

  5. Hierarchical Control of Parallel AC-DC Converter Interfaces for Hybrid Microgrids

    Lu, Xiaonan; Guerrero, Josep M.; Sun, Kai

    2014-01-01

    In this paper, a hierarchical control system for parallel power electronics interfaces between ac bus and dc bus in a hybrid microgrid is presented. Both standalone and grid-connected operation modes in the dc side of the microgrid are analyzed. Concretely, a three-level hierarchical control system...... equal or proportional dc load current sharing. The common secondary control level is designed to eliminate the dc bus voltage deviation produced by the droop control, with dc bus voltage in the hybrid microgrid boosted to an acceptable range. After guaranteeing the performance of the dc side standalone...

  6. Generation-Side Power Scheduling in a Grid-Connected DC Microgrid

    Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Meng, Lexuan

    2015-01-01

    In this paper, a constrained mixed-integer programming model for scheduling the active power supplied by the generation units in storage-based DC microgrids is presented. The optimization problem minimizes operating costs taking into account a two-stage mode operation of the energy storage system...... so that a more accurate model for optimization of the microgrid operation can be obtained. The model is used in a particular grid-connected DC microgrid that includes two renewable energy sources and an energy storage system which supply a critical load. The results of the scheduling process...

  7. Virtual Impedance Based Stability Improvement for DC Microgrids with Constant Power Loads

    Lu, Xiaonan; Sun, Kai; Huang, Lipei

    2014-01-01

    DC microgrid provides an efficient way to integrate different kinds of renewable energy sources with DC couplings. In this paper, in order to improve the stability of DC microgrids with constant power loads (CPLs), a virtual impedance based method is proposed. The CPLs have inherent instability....... To validate the stability with the above stabilizers in a DC microgrid with parallel interfacing converters and CPL, the impedance matching approach is employed. The output impedance of the source converter and input impedance of the load are calculated respectively, and the influence of droop control...

  8. Design and Implementation of the Battery Energy Storage System in DC Micro-Grid Systems

    Yuan-Chih Chang

    2018-06-01

    Full Text Available The design and implementation of the battery energy storage system in DC micro-grid systems is demonstrated in this paper. The battery energy storage system (BESS is an important part of a DC micro-grid because renewable energy generation sources are fluctuating. The BESS can provide energy while the renewable energy is absent in the DC micro-grid. The circuit topology of the proposed BESS will be introduced. The design of the voltage controller and the current controller for the battery charger/discharger are also illustrated. Finally, experimental results are provided to validate the performance of the BESS.

  9. Voltage-Based Control of a Smart Transformer in a Microgrid

    Vandoorn, T. L.; De Kooning, J. D. M.; Meersman, B.

    2013-01-01

    For the islanded operation of a microgrid, several control strategies have been developed. For example, voltage-based droop control can be implemented for the active power control of the generators and the control of the active loads. One of the main advantages of a microgrid is that it can...... of common coupling. This paper addresses this issue by introducing the concept of a smart transformer (ST) at the point of common coupling. This unit controls the active power exchange between a microgrid and the utility grid dependent on the state of both networks and other information communicated...

  10. Pricing of Vehicle-to-Grid Services in a Microgrid by Nash Bargaining Theory

    Sarparandeh, Mohammad Hossein; Ehsan, Mehdi

    2017-01-01

    Owners of electric vehicles (EVs) can offer the storage capacity of their batteries to the operator of a microgrid as a service called vehicle-to-grid (V2G) to hold the balance between supply and demand of electricity, particularly when the microgrid has intermittent renewable energy sources. Literature review implies that V2G has economic benefits for both microgrid operator and EV owners, but it is unclear how these benefits are divided between them. The challenge grows when the policy make...

  11. Guidelines for Implementing Advanced Distribution Management Systems-Requirements for DMS Integration with DERMS and Microgrids

    Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Chen [Argonne National Lab. (ANL), Argonne, IL (United States); Lu, Xiaonan [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-08-01

    This guideline focuses on the integration of DMS with DERMS and microgrids connected to the distribution grid by defining generic and fundamental design and implementation principles and strategies. It starts by addressing the current status, objectives, and core functionalities of each system, and then discusses the new challenges and the common principles of DMS design and implementation for integration with DERMS and microgrids to realize enhanced grid operation reliability and quality power delivery to consumers while also achieving the maximum energy economics from the DER and microgrid connections.

  12. Event-triggered hybrid control based on multi-Agent systems for Microgrids

    Dou, Chun-xia; Liu, Bin; Guerrero, Josep M.

    2014-01-01

    This paper is focused on a multi-agent system based event-triggered hybrid control for intelligently restructuring the operating mode of an microgrid (MG) to ensure the energy supply with high security, stability and cost effectiveness. Due to the microgrid is composed of different types...... of distributed energy resources, thus it is typical hybrid dynamic network. Considering the complex hybrid behaviors, a hierarchical decentralized coordinated control scheme is firstly constructed based on multi-agent sys-tem, then, the hybrid model of the microgrid is built by using differential hybrid Petri...

  13. Optimization for Customized Power Quality Service in Multibus Microgrids

    Meng, Lexuan; Guerrero, Josep M.

    2017-01-01

    Power quality requirements for different consumers and electric equipment are distinctive. Conventionally, common power quality standards are applied to the whole power grid inducing debate between technical commissions. Customized power quality standards for different consumers become a widely...... accepted solution. The main challenge is on the proper regulation of power quality in different areas. This paper considers a multibus microgrid system, where the power quality in each area has individual adjustable standard. Voltage unbalance, induced by connection of single-phase loads, is taken...

  14. Load Frequency Control of AC Microgrid Interconnected Thermal Power System

    Lal, Deepak Kumar; Barisal, Ajit Kumar

    2017-08-01

    In this paper, a microgrid (MG) power generation system is interconnected with a single area reheat thermal power system for load frequency control study. A new meta-heuristic optimization algorithm i.e. Moth-Flame Optimization (MFO) algorithm is applied to evaluate optimal gains of the fuzzy based proportional, integral and derivative (PID) controllers. The system dynamic performance is studied by comparing the results with MFO optimized classical PI/PID controllers. Also the system performance is investigated with fuzzy PID controller optimized by recently developed grey wolf optimizer (GWO) algorithm, which has proven its superiority over other previously developed algorithm in many interconnected power systems.

  15. Secondary control for voltage unbalance compensation in an islanded microgrid

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    In this paper, the concept of secondary control is applied for voltage unbalance compensation in an islanded microgrid. The aim of the proposed control approach is to enhance the voltage quality at the point of common coupling (PCC). Unbalance compensation is achieved by proper control...... of distributed generators (DGs). The DGs control structure mainly consists of active and reactive power controllers, virtual impedance loop and voltage and current proportional-resonant controllers. Simulation results are presented for different cases. The results show the effectiveness of the proposed approach...

  16. Active Power Regulation based on Droop for AC Microgrid

    Li, Chendan; Coelho, Ernane A. A.; Firoozabadi, Mehdi Savaghebi

    2015-01-01

    In this paper, two different control strategies are proposed to address the active power regulation issue in AC microgrids. The principle of power regulation in the droop controller is firstly introduced. Frequency scheduling and droop gain scheduling on top of droop control is proposed...... to successfully follow the active power command. The limitation of each method is discussed in term of small signal stability and light load sharing, respectively. Discussion on the effects of power command is also given. The simulation is carried out for both the strategies to verify the active power control...

  17. Power Quality in DC Power Distribution Systems and Microgrids

    Stephen Whaite

    2015-05-01

    Full Text Available This review paper discusses power quality considerations for direct current (DC electric power distribution systems, particularly DC microgrids. First, four selected sample DC architectures are discussed to provide motivation for the consideration of power quality in DC systems. Second, a brief overview of power quality challenges in conventional alternating current (AC distribution systems is given to establish the field of power quality. Finally, a survey of literature addressing power quality issues in DC systems is presented, and necessary power quality considerations in DC distribution system design and operation are discussed.

  18. Multiuser Communication Through Power Talk in DC MicroGrids

    Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

    2016-01-01

    Power talk is a novel ultra narrow-band powerline communication (UNB-PLC) technique for communication among control units in MicroGrids (MGs). Unlike the existing UNB-PLC solutions, power talk does not require installation of additional dedicated communication hardware and, instead, uses only...... transmits at a time, and full duplex, where all units transmit and receive simultaneously. We apply the concepts of signaling space, where the power talk symbol constellations are constructed, and detection space, where the demodulation of the symbols is performed. The proposed communication technique...

  19. Reviewing Microgrids from a Multi-Agent Systems Perspective

    Jorge J. Gomez-Sanz

    2014-05-01

    Full Text Available The construction of Smart Grids leads to the main question of what kind of intelligence such grids require and how to build it. Some authors choose an agent based solution to realize this intelligence. However, there may be some misunderstandings in the way this technology is being applied. This paper exposes some considerations of this subject, focusing on the Microgrid level, and shows a practical example through INGENIAS methodology, which is a methodology for the development of Agent Oriented systems that applies Model Driven Development techniques to produce fully functional Multi-Agent Systems.

  20. Calibration method of microgrid polarimeters with image interpolation.

    Chen, Zhenyue; Wang, Xia; Liang, Rongguang

    2015-02-10

    Microgrid polarimeters have large advantages over conventional polarimeters because of the snapshot nature and because they have no moving parts. However, they also suffer from several error sources, such as fixed pattern noise (FPN), photon response nonuniformity (PRNU), pixel cross talk, and instantaneous field-of-view (IFOV) error. A characterization method is proposed to improve the measurement accuracy in visible waveband. We first calibrate the camera with uniform illumination so that the response of the sensor is uniform over the entire field of view without IFOV error. Then a spline interpolation method is implemented to minimize IFOV error. Experimental results show the proposed method can effectively minimize the FPN and PRNU.

  1. A review on distributed energy resources and MicroGrid

    Jiayi, Huang; Chuanwen, Jiang; Rong, Xu [Department of Electrical Engineering, Shanghai Jiaotong University, Huashan Road 1954, Shanghai 200030 (China)

    2008-12-15

    The distributed energy resources (DER) comprise several technologies, such as diesel engines, micro turbines, fuel cells, photovoltaic, small wind turbines, etc. The coordinated operation and control of DER together with controllable loads and storage devices, such as flywheels, energy capacitors and batteries are central to the concept of MicroGrid (MG). MG can operate interconnected to the main distribution grid, or in an islanded mode. This paper reviews the researches and studies on MG technology. The operation of MG and the MG in the market environment are also described in the paper. (author)

  2. Boston Community Energy Study - Zonal Analysis for Urban Microgrids

    2016-03-01

    30 0.25 Solar Thermal 0 500 15 0.5 Air Source Heat Pump 0 70 10 0.52 Ground Source Heat Pump 0 80 10 0.32 is defined in Equation 3. For this analysis...were capped at 100 kW each due to roof area constraints. All microgrids were found to benefit from large air source heat pumps due to the low assumed...significant fraction of the cost of electricity. This implies that it is advantageous to purchase fuel to produce electricity, and then dump the heat

  3. Community Microgrid Based on Micro-Wind Generation System

    Mariam, Lubna; Basu, Malabika; Conlon, Michael

    2013-01-01

    Penetration of renewable energy sources (such as solar/wind) are being explored mostly as micro power generation (μGen) or mega power plant system. In recent years, emphasis has been given on Microgrid (μGrid) systems because of their few advantages over μGen systems in terms of power quality, stability, reliability, economics etc. But the commercial installation of the μGrid system is not yet progressing significantly. This paper presents the techno-economic aspects of μGen and μGrid systems...

  4. Microgrid Controller Design, Implementation, and Deployment: A Journey from Conception to Implementation at the Philadelphia Navy Yard

    Uluski, R.; Kumar, J.; Venkata, S. S. Mani; Vishwakarma, D.; Schneider, K.; Mehrizi-Sani, Ali; Terry, Rudy; Agate, Will

    2017-07-01

    The Philadelphia Navy Yard is a fast-evolving community microgrid, currently home to over 150 companies and four Navy activity centers occupying nearly 7 million ft2 of buildings in which approximately 12,000 people are employed. The Navy Yard (TNY) is a national center of excellence for energy research, education, and commercialization, focused specifically on community microgrid design and development. TNY microgrid is equipped with the most cost-effective and sustainable means for meeting electric capacity and energy needs through renewable resources, energy efficiency, and distribution grid infrastructure. This article briefly describes how the community microgrid was conceived and planned to produce a great success story of microgrid implementation and the details of the design, development, and implementation of the TNY microgrid controller.

  5. Self-Excited Induction Generator Based Microgrid with Supercapacitor Energy Storage to Support the Start-up of Dynamic Loads

    ION, C. P.

    2018-05-01

    Full Text Available A supercapacitor storage system (SCSS is used for improving the dynamic performances of a microgrid (MG fed by a self-excited induction generator (SEIG, in the case of the direct start-up of an induction motor (IM of comparable power. The primary control system contains a voltage source inverter (VSI with a dump load (DL, to which the SCSS is added. The control strategy for the SCSS consists of injecting power into the VSI DC-link when, because of the overload created by the IM, the DC voltage decreases under the acceptable limit. Thus, the overall performance of the SEIG-supplied MG is significantly improved. Simulations and experimental results accomplished on a laboratory-scale MG validate the effectiveness of the proposed control structure.

  6. A Hierarchical Control Scheme for Reactive Power and Harmonic Current Sharing in Islanded Microgrids

    Lorzadeh, Iman; Firoozabadi, Mehdi Savaghebi; Askarian Abyaneh, Hossein

    2015-01-01

    In this paper, a hierarchical control scheme consisting of primary and secondary levels is proposed for achieving accurate reactive power and harmonic currents sharing among interface inverters of distributed generators (DGs) in islanded microgrids. Firstly, fundamental and main harmonic componen...

  7. An improved control method of power electronic converters in low voltage micro-grid

    Xiaofeng, Sun; Qingqiu, Lv; Yanjun, Tian

    2011-01-01

    control of the voltage and frequency deviation added to power references could achieve secondary regulation of the voltage and frequency. In this paper, the authors take the steady and transient transition of grid connecting and disconnecting of the micro-grid as an example, and demonstrate......With the increasing acceptance, micro-grid, combined with distributed generation (DG), may be operated in two modes: grid-connected mode and island mode. In grid connected mode, energy management is the control objective. While in island mode, the control of Voltage and frequency will take...... the place. The conventional droop control can perform the energy management in grid-connected mode, but may not so effective when micro-grid transferring between grid-connected mode and island mode. The paper analysis the micro-grid in different modes (Conventional droop control, Voltage reference...

  8. Constructing A Multi-Microgrid with the Inclusion of Renewable Energy in Oman's Rural Power System

    Nasser Hosseinzadeh

    2018-01-01

    Full Text Available This paper investigates the possibility of constructing multi-microgrids by interlinking the rural area systems in the Al Wusta governorate of the Sultanate of Oman, which are currently being supplied by diesel generators. It is proposed to enhance the rural system under study by switching off small diesel stations and replacing them with wind turbines. The microgrids formed in this way are then interlinked together to create multi-microgrids. The paper studies the interlinked multi-microgrids under different scenarios; in terms of voltage profiles and power flow using the ETAP software package. This study contributes to the feasibility study of retiring some diesel power plants and using renewable energy resources in rural Oman.

  9. Research on a Micro-Grid Frequency Modulation Strategy Based on Optimal Utilization of Air Conditioners

    Qingzhu Wan

    2016-12-01

    Full Text Available With the proportion of air conditioners increasing gradually, they can provide a certain amount of frequency-controlled reserves for a micro-grid. Optimizing utilization of air conditioners and considering load response characteristics and customer comfort, the frequency adjustment model is a quadratic function model between the trigger temperature of the air conditioner compressor, and frequency variation is provided, which can be used to regulate the trigger temperature of the air conditioner when the micro-grid frequency rises and falls. This frequency adjustment model combines a primary frequency modulation method and a secondary frequency modulation method of the energy storage system, in order to optimize the frequency of a micro-grid. The simulation results show that the frequency modulation strategy for air conditioners can effectively improve the frequency modulation ability of air conditioners and frequency modulation effects of a micro-grid in coordination with an energy storage system.

  10. Economic Dispatch for Operating Cost Minimization under Real Time Pricing in Droop Controlled DC Microgrid

    Li, Chendan; Federico, de Bosio; Chen, Fang

    2017-01-01

    In this paper, an economic dispatch problem for total operation cost minimization in DC microgrids is formulated. An operating cost is associated with each generator in the microgrid, including the utility grid, combining the cost-efficiency of the system with demand response requirements...... achieving higher control accuracy and faster response. The optimization problem is solved in a heuristic method. In order to test the proposed algorithm, a six-bus droop-controlled DC microgrid is used in the case studies. Simulation results show that under variable renewable energy generation, load...... of the utility. The power flow model is included in the optimization problem, thus the transmission losses can be considered for generation dispatch. By considering the primary (local) control of the grid-forming converters of a microgrid, optimal parameters can be directly applied to this control level, thus...

  11. Hierarchical Control Scheme for Voltage Harmonics Compensation in an Islanded Droop-Controlled Microgrid

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    In this paper, a microgrid hierarchical control scheme is proposed which includes primary and secondary control levels. The primary level comprises distributed generators (DGs) local controllers. The local controller mainly consists of active and reactive power controllers, voltage and current...... controllers, and virtual impedance loop. A novel virtual impedance structure is proposed to achieve proper sharing of non-fundamental power among the microgrid DGs. The secondary level is designed to manage compensation of voltage harmonics at the microgrid load bus (LB) to which the sensitive loads may...... be connected. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values is directed by the secondary level. These functions are achieved by sending proper control signals to the local controllers. The simulation results show the effectiveness of the proposed control scheme....

  12. Virtual Power Plant and Microgrids controller for Energy Management based on optimization techniques

    Maher G. M. Abdolrasol

    2017-06-01

    Full Text Available This paper discuss virtual power plant (VPP and Microgrid controller for energy management system (EMS based on optimization techniques by using two optimization techniques namely Backtracking search algorithm (BSA and particle swarm optimization algorithm (PSO. The research proposes use of multi Microgrid in the distribution networks to aggregate the power form distribution generation and form it into single Microgrid and let these Microgrid deal directly with the central organizer called virtual power plant. VPP duties are price forecast, demand forecast, weather forecast, production forecast, shedding loads, make intelligent decision and for aggregate & optimizes the data. This huge system has been tested and simulated by using Matlab simulink. These paper shows optimizations of two methods were really significant in the results. But BSA is better than PSO to search for better parameters which could make more power saving as in the results and the discussion.

  13. Performance Analysis of Autonomous Microgrid Subsequent to Symmetrical and Unsymmetrical Fault Triggered Condition

    Natesan, Chitra; Ajithan, Senthil Kumar; Mani, Shobana; Palani, Priyadharshini; Kandhasamy, Prabaakaran

    2014-01-01

    Hi-tech scenario and the ecological compression are the key point to drive the intervention of the renewable in the distribution system. In the perspective of complex power system planners, the transient performance of the microgrid is the main concern. For that purpose, various fault cases are explored in order to examine the microgrid transient performance when subjected to accidental events. In this work, the microgrid is modelled with two distributed generations (DGs) tied with a converter separately. With this intention, droop control strategy is adopted for the microsources to examine the microgrid performance during the symmetrical and unsymmetrical fault events. The ability of the control strategy adopted in this work and its effectiveness are evaluated through Matlab/Simulink platform. PMID:25162062

  14. Sliding Mode Controller and Lyapunov Redesign Controller to Improve Microgrid Stability

    Hossain, Eklas; Perez, Ron; Padmanaban, Sanjeevikumar

    2017-01-01

    technique is used to enhance stability of microgrids. Besides adopting this technique here, Sliding Mode Controller (SMC) and Lyapunov Redesign Controller (LRC), two of the most prominent nonlinear control techniques, are individually implemented to control microgrid system stability with desired robustness....... CPL power is then varied to compare robustness of these two control techniques. This investigation revealed the better performance of the LRC system compared to SMC to retain stability in microgrid with dense CPL load. All the necessary results are simulated in Matlab/Simulink platform for authentic......To mitigate the microgrid instability despite the presence of dense Constant Power Load (CPL) loads in the system, a number of compensation techniques have already been gone through extensive research, proposed, and implemented around the world. In this paper, a storage based load side compensation...

  15. Fuzzy Secondary Controller for Autonomous Stand-alone and Grid-connected AC Microgrid

    Neves, Rodolpho V. A.; Machado, Ricardo Q.; Oliveira, Vilma A.

    2016-01-01

    The present paper adresses the AC microgrid control issue using the hierarchical control structure and droop controllers for load sharing. Once the droop controllers impose an operation with frequency and voltage deviations, depending on the load and droop parameters, a hierarchical control...... structure must be added to change the droop controller operating points. The hierarchical controllers operate with local measurements and shared signals from communication links among the distributed generation systems connected to the microgrid. Depending on the geographical size of the microgrid......, the communication links can be economically unviable. This paper thus proposes a fuzzy secondary controller for AC microgrids to reduce the link communication dependency by using only local measurements. The simulation results show that the deviations as happened with the conventional secondary controllers can...

  16. Autonomous Control of Interlinking Converter With Energy Storage in Hybrid AC–DC Microgrid

    Loh, Poh Chiang; Li, Ding; Chai, Yi Kang

    2013-01-01

    , simplicity, and industry relevance of the converter. The desired operating features of the hybrid microgrid can then be added through this interlinking converter. To demonstrate, an appropriate control scheme is now developed for controlling the interlinking converter. The objective is to keep the hybrid......The coexistence of ac and dc subgrids in a hybrid microgrid is likely given that modern distributed sources can either be ac or dc. Linking these subgrids is a power converter, whose topology should preferably be not too unconventional. This is to avoid unnecessary compromises to reliability...... microgrid in autonomous operation with active power proportionally shared among its distributed sources. Power sharing here should depend only on the source ratings and not their placements within the hybrid microgrid. The proposed scheme can also be extended to include energy storage within...

  17. Energy and operation management of a microgrid using particle swarm optimization

    Radosavljević, Jordan; Jevtić, Miroljub; Klimenta, Dardan

    2016-05-01

    This article presents an efficient algorithm based on particle swarm optimization (PSO) for energy and operation management (EOM) of a microgrid including different distributed generation units and energy storage devices. The proposed approach employs PSO to minimize the total energy and operating cost of the microgrid via optimal adjustment of the control variables of the EOM, while satisfying various operating constraints. Owing to the stochastic nature of energy produced from renewable sources, i.e. wind turbines and photovoltaic systems, as well as load uncertainties and market prices, a probabilistic approach in the EOM is introduced. The proposed method is examined and tested on a typical grid-connected microgrid including fuel cell, gas-fired microturbine, wind turbine, photovoltaic and energy storage devices. The obtained results prove the efficiency of the proposed approach to solve the EOM of the microgrids.

  18. Optimal Energy Management of Multi-Microgrids with Sequentially Coordinated Operations

    Nah-Oak Song

    2015-08-01

    Full Text Available We propose an optimal electric energy management of a cooperative multi-microgrid community with sequentially coordinated operations. The sequentially coordinated operations are suggested to distribute computational burden and yet to make the optimal 24 energy management of multi-microgrids possible. The sequential operations are mathematically modeled to find the optimal operation conditions and illustrated with physical interpretation of how to achieve optimal energy management in the cooperative multi-microgrid community. This global electric energy optimization of the cooperative community is realized by the ancillary internal trading between the microgrids in the cooperative community which reduces the extra cost from unnecessary external trading by adjusting the electric energy production amounts of combined heat and power (CHP generators and amounts of both internal and external electric energy trading of the cooperative community. A simulation study is also conducted to validate the proposed mathematical energy management models.

  19. Optimization under uncertainty of a biomass-integrated renewable energy microgrid with energy storage

    Zheng, Yingying; Jenkins, Bryan M.; Kornbluth, Kurt

    2018-01-01

    Deterministic constrained optimization and stochastic optimization approaches were used to evaluate uncertainties in biomass-integrated microgrids supplying both electricity and heat. An economic linear programming model with a sliding time window was developed to assess design and scheduling...... of biomass combined heat and power (BCHP) based microgrid systems. Other available technologies considered within the microgrid were small-scale wind turbines, photovoltaic modules (PV), producer gas storage, battery storage, thermal energy storage and heat-only boilers. As an illustrative example, a case...... study was examined for a conceptual utility grid-connected microgrid application in Davis, California. The results show that for the assumptions used, a BCHP/PV with battery storage combination is the most cost effective design based on the assumed energy load profile, local climate data, utility tariff...

  20. Performance Analysis of Autonomous Microgrid Subsequent to Symmetrical and Unsymmetrical Fault Triggered Condition

    Chitra Natesan

    2014-01-01

    Full Text Available Hi-tech scenario and the ecological compression are the key point to drive the intervention of the renewable in the distribution system. In the perspective of complex power system planners, the transient performance of the microgrid is the main concern. For that purpose, various fault cases are explored in order to examine the microgrid transient performance when subjected to accidental events. In this work, the microgrid is modelled with two distributed generations (DGs tied with a converter separately. With this intention, droop control strategy is adopted for the microsources to examine the microgrid performance during the symmetrical and unsymmetrical fault events. The ability of the control strategy adopted in this work and its effectiveness are evaluated through Matlab/Simulink platform.

  1. Strategic optimisation of microgrid by evolving a unitised regenerative fuel cell system operational criterion

    Bhansali, Gaurav; Singh, Bhanu Pratap; Kumar, Rajesh

    2016-09-01

    In this paper, the problem of microgrid optimisation with storage has been addressed in an unaccounted way rather than confining it to loss minimisation. Unitised regenerative fuel cell (URFC) systems have been studied and employed in microgrids to store energy and feed it back into the system when required. A value function-dependent on line losses, URFC system operational cost and stored energy at the end of the day are defined here. The function is highly complex, nonlinear and multi dimensional in nature. Therefore, heuristic optimisation techniques in combination with load flow analysis are used here to resolve the network and time domain complexity related with the problem. Particle swarm optimisation with the forward/backward sweep algorithm ensures optimal operation of microgrid thereby minimising the operational cost of the microgrid. Results are shown and are found to be consistently improving with evolution of the solution strategy.

  2. State-Of-The-Art in Microgrid-Integrated Distributed Energy Storage Sizing

    Ibrahim Alsaidan

    2017-09-01

    Full Text Available Distributed energy storage (DES plays an important role in microgrid operation and control, as it can potentially improve local reliability and resilience, reduce operation cost, and mitigate challenges caused by high penetration renewable generation. However, to ensure an acceptable economic and technical performance, DES must be optimally sized and placed. This paper reviews the existing DES sizing methods for microgrid applications and presents a generic sizing method that enables microgrid planners to efficiently determine the optimal DES size, technology, and location. The proposed method takes into consideration the impact of DES operation on its lifetime to enhance the obtained results accuracy and practicality. The presented model can be used for both grid-tied (considering both grid-connected and islanded modes and isolated microgrids.

  3. Performance analysis of autonomous microgrid subsequent to symmetrical and unsymmetrical fault triggered condition.

    Natesan, Chitra; Ajithan, Senthil Kumar; Mani, Shobana; Palani, Priyadharshini; Kandhasamy, Prabaakaran

    2014-01-01

    Hi-tech scenario and the ecological compression are the key point to drive the intervention of the renewable in the distribution system. In the perspective of complex power system planners, the transient performance of the microgrid is the main concern. For that purpose, various fault cases are explored in order to examine the microgrid transient performance when subjected to accidental events. In this work, the microgrid is modelled with two distributed generations (DGs) tied with a converter separately. With this intention, droop control strategy is adopted for the microsources to examine the microgrid performance during the symmetrical and unsymmetrical fault events. The ability of the control strategy adopted in this work and its effectiveness are evaluated through Matlab/Simulink platform.

  4. Design and Field Tests of an Inverted Based Remote MicroGrid on a Korean Island

    Woo-Kyu Chae

    2015-08-01

    Full Text Available In this paper, we present the results of an economic feasibility study and propose a system structure to test and maintain electrical stability. In addition, we present real operation results after constructing a remote microgrid on an island in South Korea. To perform the economic feasibility study, a commercial tool called HOMER was used. The developed remote microgrid consists of a 400 kW wind turbine (WT generator, 314 kW photovoltaic (PV generator, 500 kVA × 2 grid forming inverter, 3 MWh lithium ion battery, and an energy management system (EMS. The predicted renewable energy fraction was 91% and real operation result was 82%. The frequency maintaining rate of the diesel power plants was 57% but the remote microgrid was 100%. To improve the operating efficiency of the remote microgrid, we investigated the output range of a diesel generator.

  5. Medium Voltage Microgrid Test Setup and Procedures Implemented on a Real Pilot Project

    Bruno Alberto Pacheco

    2018-01-01

    Full Text Available This paper presents various concepts related to the application of a microgrid pilot project in a residential condominium at Fortaleza / CE – Brazil, such as battery energy system, renewable and distributed generation, islanding recloser and all different units using interface based on power electronics. This papers main objective is to create information about microgrid operation and the interaction between its main equipment, such as power converters, utility energy distribution system and control units responsible for algorithms and changes in microgrids operation mode. This information is important for understanding the need for a test setup construction. To perform the test procedures, a temporary setup in a controlled environment within the microgrid is proposed. During the test periods, intentional power outages are required to evaluate the operating mode switching on each unit. The test setup described in this paper aims to mitigate the tests effects on other residential units inside the condominium.

  6. A Communication-Supported Comprehensive Protection Strategy for Converter-Interfaced Islanded Microgrids

    Dehua Zheng

    2018-04-01

    Full Text Available The deployment of distributed generators (DGs gives rise to several challenges for a microgrid or conventional distribution feeder, regarding control and protection issues. The major ones are: bi-directional flow of power, changes in fault current magnitude, and continuous changes in operational configuration due to both the plug-and-play of DGs and loads, and the intermittency of the renewable DGs. This issue is exacerbated when the microgrid contains several converter-interfaced DGs and operates in the islanded mode of operation. Hence, conventional protection strategies and relaying techniques will no longer be sufficient to protect islanded microgrids against network faults and disturbance conditions. This paper proposes a fast and reliable communication-supported protection strategy for ensuring the safe operation of converter-interfaced islanded microgrids. The strategy is implementable using commercially accessible microprocessor based digital relays, and is applicable for the protection of low voltage islanded microgrids. It provides backup protection to handle communication failures and malfunctions of protective devices. The paper also presents the detailed structural layout of the digital relay, which executes the proposed protection strategy. A number of improvements are proposed to find an alternative method for conventional overcurrent relays to reliably detect small-magnitude fault currents and high impedance faults, commonly encountered in converter-interfaced islanded microgrids. A simple and economical bus protection method is also proposed. Several simulations are conducted on a comprehensive model of a realistic operational industrial microgrid (Goldwind Smart Microgrid System using PSCAD/EMTDC software environment—for different case studies and fault scenarios—to verify the effectiveness of the present strategy and its digital relay.

  7. A Bankruptcy Problem Approach to Load-shedding in Multiagent-based Microgrid Operation

    Kim, Hak-Man; Kinoshita, Tetsuo; Lim, Yujin; Kim, Tai-Hoon

    2010-01-01

    A microgrid is composed of distributed power generation systems (DGs), distributed energy storage devices (DSs), and loads. To maintain a specific frequency in the islanded mode as an important requirement,  the control of DGs’ output and charge action of DSs are used in supply surplus conditions and load-shedding and discharge action of DSs are used in supply shortage conditions. Recently, multiagent systems for autonomous microgrid operation have been studied. Especially, load-shedding, whi...

  8. Management Controller for a DC MicroGrid integrating Renewables and Storages

    Iovine , Alessio; Damm , Gilney; De Santis , Elena; Di Benedetto , Maria Domenica

    2017-01-01

    International audience; DC MicroGrids present an increasing interest as they represent an advantageous solution for interconnecting renewable energy sources, storage systems and loads as electric vehicles. A high-level management system able to calculate the optimal reference values for the local controllers of each of the DC MicroGrid interconnected devices is introduced in this paper. Both the changing environmental conditions and the expected load variations are taken into account. The con...

  9. Modelling and control of a microgrid including photovoltaic and wind generation

    Hussain, Mohammed Touseef

    Extensive increase of distributed generation (DG) penetration and the existence of multiple DG units at distribution level have introduced the notion of micro-grid. This thesis develops a detailed non-linear and small-signal dynamic model of a microgrid that includes PV, wind and conventional small scale generation along with their power electronics interfaces and the filters. The models developed evaluate the amount of generation mix from various DGs for satisfactory steady state operation of the microgrid. In order to understand the interaction of the DGs on microgrid system initially two simpler configurations were considered. The first one consists of microalternator, PV and their electronics, and the second system consists of microalternator and wind system each connected to the power system grid. Nonlinear and linear state space model of each microgrid are developed. Small signal analysis showed that the large participation of PV/wind can drive the microgrid to the brink of unstable region without adequate control. Non-linear simulations are carried out to verify the results obtained through small-signal analysis. The role of the extent of generation mix of a composite microgrid consisting of wind, PV and conventional generation was investigated next. The findings of the smaller systems were verified through nonlinear and small signal modeling. A central supervisory capacitor energy storage controller interfaced through a STATCOM was proposed to monitor and enhance the microgrid operation. The potential of various control inputs to provide additional damping to the system has been evaluated through decomposition techniques. The signals identified to have damping contents were employed to design the supervisory control system. The controller gains were tuned through an optimal pole placement technique. Simulation studies demonstrate that the STATCOM voltage phase angle and PV inverter phase angle were the best inputs for enhanced stability boundaries.

  10. Flexible Design and Operation of a Smart Charging Microgrid (Briefing Charts)

    2014-04-08

    release; distribution unlimited 13. SUPPLEMENTARY NOTES Briefing Charts for SAE World Congress 2014 14. ABSTRACT A microgrid is a controllable ...UNCLASSIFIED Distribution Statement A: Approved for Public Release Flexible Design and Operation of a Smart Charging Microgrid Annette G... control number. 1. REPORT DATE 08 APR 2014 2. REPORT TYPE Briefing Charts 3. DATES COVERED 08-01-2014 to 09-03-2014 4. TITLE AND SUBTITLE

  11. Optimal Dispatch of an Industrial Microgrid with a Mixed Portfolio of Distributed Energy Resources

    You, Shi; Zong, Yi; Bindner, Henrik W.

    2014-01-01

    Local brownouts are a nuisance and have driven consumers to take greater responsibility for their electricity supply – particularly industries and communities with a critical need for reliable and safe power. By deploying a Microgrid on their own site, the consumers could benefit from having...... this interoperable grid solution with respect to improved energy efficiency, system reliability and power quality. When the on-site generation is from renewables, external incentives and system sustainability could make the Microgrid solution even more attractive...

  12. Stability Analysis of a Microgrid System based on Inverter-Interfaced Distributed Generators

    CUSIDO, J.

    2013-08-01

    Full Text Available This paper presents a phase-plane trajectory analysis and the appliance of Lyapunov's methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.

  13. A novel wavelet-based feature extraction from common mode currents for fault location in a residential DC microgrid

    Beheshtaein, Siavash; Yu, Junyang; Cuzner, Rob

    2017-01-01

    approaches have been developed that enable construction of scalable microgrids based on PV and battery storage. However, as these systems proliferate, it will be necessary to develop safe and reliable methods for fault protection. Ground faults are of specific concern because, in many cases, cables...... are buried underground. At the same time, microgrids include current monitoring and processing capability wherever an energy resource interfaces to the microgrid through a power electronic converter. This paper discusses methods for identifying ground fault behavior within standard DC microgrid structures...

  14. Virtual Inertia Control-Based Model Predictive Control for Microgrid Frequency Stabilization Considering High Renewable Energy Integration

    Thongchart Kerdphol

    2017-05-01

    Full Text Available Renewable energy sources (RESs, such as wind and solar generations, equip inverters to connect to the microgrids. These inverters do not have any rotating mass, thus lowering the overall system inertia. This low system inertia issue could affect the microgrid stability and resiliency in the situation of uncertainties. Today’s microgrids will become unstable if the capacity of RESs become larger and larger, leading to the weakening of microgrid stability and resilience. This paper addresses a new concept of a microgrid control incorporating a virtual inertia system based on the model predictive control (MPC to emulate virtual inertia into the microgrid control loop, thus stabilizing microgrid frequency during high penetration of RESs. The additional controller of virtual inertia is applied to the microgrid, employing MPC with virtual inertia response. System modeling and simulations are carried out using MATLAB/Simulink® software. The simulation results confirm the superior robustness and frequency stabilization effect of the proposed MPC-based virtual inertia control in comparison to the fuzzy logic system and conventional virtual inertia control in a system with high integration of RESs. The proposed MPC-based virtual inertia control is able to improve the robustness and frequency stabilization of the microgrid effectively.

  15. Intelligent Control for a DC Micro-Grid System

    Martino, Michele; Quiñones, Yamshid Farhat; Raboni, Pietro

    2012-01-01

    This paper presents the dynamic response of a DC–micro-grid (DC-MG) controlled in master-slave mode. The benefits of the micro-grids (MGs) are the low cost in terms of power electronics converters and the high reliability and quality, even in case of loss connection to the transmission system. A ...... the units, especially in case of variable weather conditions with different DC loads. Thus the voltage level of the system and the power flow are shown, out of a detailed description of the power electronic interfaces featuring the distributed generators (DGs).......This paper presents the dynamic response of a DC–micro-grid (DC-MG) controlled in master-slave mode. The benefits of the micro-grids (MGs) are the low cost in terms of power electronics converters and the high reliability and quality, even in case of loss connection to the transmission system. A DC......-MG in fact can survive in standalone mode if properly managed. The considered system is made by a photovoltaic array (PV), a wind turbine (WT), a gas engine (GE) and an energy storage system (ESS). The DC-MG behavior is analyzed in different scenarios to demonstrate the efficacy of the control for all...

  16. Alternative Energetics DC Microgrid With Hydrogen Energy Storage System

    Zaļeskis Genadijs

    2016-12-01

    Full Text Available This paper is related to an alternative energetics microgrid with a wind generator and a hydrogen energy storage system. The main aim of this research is the development of solutions for effective use of the wind generators in alternative energetics devices, at the same time providing uninterrupted power supply of the critical loads. In this research, it was accepted that the alternative energetics microgrid operates in an autonomous mode and the connection to the conventional power grid is not used. In the case when wind speed is low, the necessary power is provided by the energy storage system, which includes a fuel cell and a tank with stored hydrogen. The theoretical analysis of the storage system operation is made. The possible usage time of the stored hydrogen depends on the available amount of hydrogen and the consumption of the hydrogen by the fuel cell. The consumption, in turn, depends on used fuel cell power. The experimental results suggest that if the wind generator can provide only a part of the needed power, the abiding power can be provided by the fuel cell. In this case, a load filter is necessary to decrease the fuel cell current pulsations.

  17. Novel optimization technique of isolated microgrid with hydrogen energy storage.

    Beshr, Eman Hassan; Abdelghany, Hazem; Eteiba, Mahmoud

    2018-01-01

    This paper presents a novel optimization technique for energy management studies of an isolated microgrid. The system is supplied by various Distributed Energy Resources (DERs), Diesel Generator (DG), a Wind Turbine Generator (WTG), Photovoltaic (PV) arrays and supported by fuel cell/electrolyzer Hydrogen storage system for short term storage. Multi-objective optimization is used through non-dominated sorting genetic algorithm to suit the load requirements under the given constraints. A novel multi-objective flower pollination algorithm is utilized to check the results. The Pros and cons of the two optimization techniques are compared and evaluated. An isolated microgrid is modelled using MATLAB software package, dispatch of active/reactive power, optimal load flow analysis with slack bus selection are carried out to be able to minimize fuel cost and line losses under realistic constraints. The performance of the system is studied and analyzed during both summer and winter conditions and three case studies are presented for each condition. The modified IEEE 15 bus system is used to validate the proposed algorithm.

  18. Gain Scheduling Control of an Islanded Microgrid Voltage

    Haritza Camblong

    2014-07-01

    Full Text Available The aim of this research study has been to design a gain scheduling (GS digital controller in order to control the voltage of an islanded microgrid in the presence of fast varying loads (FVLs, and to compare it to a robust controller. The inverter which feeds the microgrid is connected to it through an inductance-capacitor-inductance (LCL filter. The oscillatory and nonlinear behaviour of the plant is analyzed in the whole operating zone. Afterwards, the design of the controllers which contain two loops in cascade are described. The first loop concerns the current control, while the second is linked to the voltage regulation. Two controllers, one defined as Robust and another one as GS controller, are designed for the two loops, emphasizing in their robustness and their ability to damp the oscillatory plant behaviour. To finish, some simulations are carried out to study and compare the two kinds of controllers in different operating points. The results show that both controllers damp the oscillatory behaviour of the plant in closed loop (CL, and that the GS controller ensures a better rejection of current disturbances from FVLs.

  19. Decentralized DC Microgrid Monitoring and Optimization via Primary Control Perturbations

    Angjelichinoski, Marko; Scaglione, Anna; Popovski, Petar; Stefanovic, Cedomir

    2018-06-01

    We treat the emerging power systems with direct current (DC) MicroGrids, characterized with high penetration of power electronic converters. We rely on the power electronics to propose a decentralized solution for autonomous learning of and adaptation to the operating conditions of the DC Mirogrids; the goal is to eliminate the need to rely on an external communication system for such purpose. The solution works within the primary droop control loops and uses only local bus voltage measurements. Each controller is able to estimate (i) the generation capacities of power sources, (ii) the load demands, and (iii) the conductances of the distribution lines. To define a well-conditioned estimation problem, we employ decentralized strategy where the primary droop controllers temporarily switch between operating points in a coordinated manner, following amplitude-modulated training sequences. We study the use of the estimator in a decentralized solution of the Optimal Economic Dispatch problem. The evaluations confirm the usefulness of the proposed solution for autonomous MicroGrid operation.

  20. A Privacy-Preserving Distributed Optimal Scheduling for Interconnected Microgrids

    Nian Liu

    2016-12-01

    Full Text Available With the development of microgrids (MGs, interconnected operation of multiple MGs is becoming a promising strategy for the smart grid. In this paper, a privacy-preserving distributed optimal scheduling method is proposed for the interconnected microgrids (IMG with a battery energy storage system (BESS and renewable energy resources (RESs. The optimal scheduling problem is modeled to minimize the coalitional operation cost of the IMG, including the fuel cost of conventional distributed generators and the life loss cost of BESSs. By using the framework of the alternating direction method of multipliers (ADMM, a distributed optimal scheduling model and an iteration solution algorithm for the IMG is introduced; only the expected exchanging power (EEP of each MG is required during the iterations. Furthermore, a privacy-preserving strategy for the sharing of the EEP among MGs is designed to work with the mechanism of the distributed algorithm. According to the security analysis, the EEP can be delivered in a cooperative and privacy-preserving way. A case study and numerical results are given in terms of the convergence of the algorithm, the comparison of the costs and the implementation efficiency.

  1. Novel optimization technique of isolated microgrid with hydrogen energy storage.

    Eman Hassan Beshr

    Full Text Available This paper presents a novel optimization technique for energy management studies of an isolated microgrid. The system is supplied by various Distributed Energy Resources (DERs, Diesel Generator (DG, a Wind Turbine Generator (WTG, Photovoltaic (PV arrays and supported by fuel cell/electrolyzer Hydrogen storage system for short term storage. Multi-objective optimization is used through non-dominated sorting genetic algorithm to suit the load requirements under the given constraints. A novel multi-objective flower pollination algorithm is utilized to check the results. The Pros and cons of the two optimization techniques are compared and evaluated. An isolated microgrid is modelled using MATLAB software package, dispatch of active/reactive power, optimal load flow analysis with slack bus selection are carried out to be able to minimize fuel cost and line losses under realistic constraints. The performance of the system is studied and analyzed during both summer and winter conditions and three case studies are presented for each condition. The modified IEEE 15 bus system is used to validate the proposed algorithm.

  2. Super-resolution for imagery from integrated microgrid polarimeters.

    Hardie, Russell C; LeMaster, Daniel A; Ratliff, Bradley M

    2011-07-04

    Imagery from microgrid polarimeters is obtained by using a mosaic of pixel-wise micropolarizers on a focal plane array (FPA). Each distinct polarization image is obtained by subsampling the full FPA image. Thus, the effective pixel pitch for each polarization channel is increased and the sampling frequency is decreased. As a result, aliasing artifacts from such undersampling can corrupt the true polarization content of the scene. Here we present the first multi-channel multi-frame super-resolution (SR) algorithms designed specifically for the problem of image restoration in microgrid polarization imagers. These SR algorithms can be used to address aliasing and other degradations, without sacrificing field of view or compromising optical resolution with an anti-aliasing filter. The new SR methods are designed to exploit correlation between the polarimetric channels. One of the new SR algorithms uses a form of regularized least squares and has an iterative solution. The other is based on the faster adaptive Wiener filter SR method. We demonstrate that the new multi-channel SR algorithms are capable of providing significant enhancement of polarimetric imagery and that they outperform their independent channel counterparts.

  3. A three-level support method for smooth switching of the micro-grid operation model

    Zong, Yuanyang; Gong, Dongliang; Zhang, Jianzhou; Liu, Bin; Wang, Yun

    2018-01-01

    Smooth switching of micro-grid between the grid-connected operation mode and off-grid operation mode is one of the key technologies to ensure it runs flexible and efficiently. The basic control strategy and the switching principle of micro-grid are analyzed in this paper. The reasons for the fluctuations of the voltage and the frequency in the switching process are analyzed from views of power balance and control strategy, and the operation mode switching strategy has been improved targeted. From the three aspects of controller’s current inner loop reference signal, voltage outer loop control strategy optimization and micro-grid energy balance management, a three-level security strategy for smooth switching of micro-grid operation mode is proposed. From the three aspects of controller’s current inner loop reference signal tracking, voltage outer loop control strategy optimization and micro-grid energy balance management, a three-level strategy for smooth switching of micro-grid operation mode is proposed. At last, it is proved by simulation that the proposed control strategy can make the switching process smooth and stable, the fluctuation problem of the voltage and frequency has been effectively improved.

  4. Study on a New Operational Mode of Economic Operation of Islanded Microgrids Using Electric Springs

    Zhao Zhiyu

    2018-01-01

    Full Text Available With the increasing penetration of intermittent renewable energy sources (RESs into microgrids, the original operation mode of power generation determined by load demand faces severe challenges due to the uncertainties of the RESs power output. The electric springs(ESs, as an emerging technology has been verified to be effective in enabling load demand to follow power generation and stabilizing fluctuation of RESs output. This paper presents a new mode of economic operation for island microgrids including non-critical loads with embedded electric springs. Its connotation includes that i the capacity of energy storage can be reduced through the interaction of the energy storage system (ESS and the electric springs, ii the electric springs reduce the stress of peak load regulation and operational cost and iii the demand of microgrids system for ramping ability of generation units is reduced with the buffer of the electric springs. Numerical results show that the coordinated operation between electric springs and energy storage system of microgrids can bring down the investment cost for the ESS and short-term operational cost in the aspect of economic dispatch, reducing requirements for the capacity and ramp ability of the energy storage system in microgrids. Energy buffering can be achieved with lower cost and the load demand can follow power generation in the new operational mode of islanded microgrids using electric springs.

  5. A Review of Predictive Software for the Design of Community Microgrids

    Mina Rahimian

    2018-01-01

    Full Text Available This paper discusses adding a spatial dimension to the design of community microgrid projects in the interest of expanding the existing discourse related to energy performance optimization measures. A multidimensional vision for designing community microgrids with higher energy performance is considered, leveraging urban form (superstructure to understand how it impacts the performance of the system’s distributed energy resources and loads (infrastructure. This vision engages the design sector in the technical conversation of developing community microgrids, leading to energy efficient designs of microgrid-connected communities well before their construction. A new generation of computational modeling and simulation tools that address this interaction are required. In order to position the research, this paper presents a survey of existing software packages, belonging to two distinct categories of modeling, simulation, and evaluation of community microgrids: the energy infrastructure modeling and the urban superstructure energy modeling. Results of this software survey identify a lack in software tools and simulation packages that simultaneously address the necessary interaction between the superstructure and infrastructure of community microgrids, given the importance of its study. Conclusions represent how a proposed experimental software prototype may fill an existing gap in current related software packages.

  6. Stability Enhancement Based on Virtual Impedance for DC Microgrids with Constant Power Loads

    Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.

    2015-01-01

    In this paper, a converter-based DC microgrid is studied. By considering the impact of each component in DC microgrids on system stability, a multi-stage configuration is employed, which includes the source stage, interface converter stage between buses and common load stage. In order to study th....... It can be seen that by using the proposed stabilizers, the unstable poles induced by the CPLs are forced to move into the stable region. The proposed method is verified by the MATLAB/Simulink model of multi-stage DC microgrids with three distributed power generation units.......In this paper, a converter-based DC microgrid is studied. By considering the impact of each component in DC microgrids on system stability, a multi-stage configuration is employed, which includes the source stage, interface converter stage between buses and common load stage. In order to study...... the overall stability of the above DC microgrid with constant power loads (CPLs), a comprehensive small-signal model is derived by analyzing the interface converters in each stage. The instability issue induced by the CPLs is revealed by using the criteria of impedance matching. Meanwhile, virtual...

  7. Efficient integration of plug-in electric vehicles via reconfigurable microgrids

    Kavousi-Fard, Abdollah; Khodaei, Amin

    2016-01-01

    This paper investigates the viability of the reconfigurable microgrids (RMGs) in facilitating the integration of plug-in electric vehicles (PEVs). The reconfiguration ability of microgrids, which is enabled by the use of remotely controlled switches (RCSs), will support the high penetration of PEVs and renewable distributed generators (DGs) while reducing the total operation cost and potentially enhance microgrid reliability. The objective of the proposed optimal scheduling problem is to minimize the total cost of power supply by distributed energy resources (DERs) and upstream network energy exchange, battery degradation cost in PEVs, cost of switching during the reconfiguration, and expected customer interruption costs as a reliability index. To address the high level of the uncertainties in the problem, a scenario-based stochastic framework is devised to capture the uncertainties associated with the charging and discharging values of PEVs, number of PEVs in each fleet, time of the daily trips for PEVs, hourly load consumption, hourly output power of renewable DGs, and hourly market price. The satisfying performance and merits of the proposed model are examined on a test microgrid. - Highlights: • Introduction of reconfigurable microgrids for providing flexible structure to manage electric loads. • Assessing the effects of the reconfiguration on the integration of PEVs. • Introduction of a stochastic framework for reducing operation and reliability costs in microgrids. • Introduction of a smart charge/discharge scheme for PEVs based on V2G during the reconfiguration.

  8. Micro-grid platform based on NODE.JS architecture, implemented in electrical network instrumentation

    Duque, M.; Cando, E.; Aguinaga, A.; Llulluna, F.; Jara, N.; Moreno, T.

    2016-05-01

    In this document, I propose a theory about the impact of systems based on microgrids in non-industrialized countries that have the goal to improve energy exploitation through alternatives methods of a clean and renewable energy generation and the creation of the app to manage the behavior of the micro-grids based on the NodeJS, Django and IOJS technologies. The micro-grids allow the optimal way to manage energy flow by electric injection directly in electric network small urban's cells in a low cost and available way. In difference from conventional systems, micro-grids can communicate between them to carry energy to places that have higher demand in accurate moments. This system does not require energy storage, so, costs are lower than conventional systems like fuel cells, solar panels or else; even though micro-grids are independent systems, they are not isolated. The impact that this analysis will generate, is the improvement of the electrical network without having greater control than an intelligent network (SMART-GRID); this leads to move to a 20% increase in energy use in a specified network; that suggest there are others sources of energy generation; but for today's needs, we need to standardize methods and remain in place to support all future technologies and the best option are the Smart Grids and Micro-Grids.

  9. Economic Dispatch for Microgrid Containing Electric Vehicles via Probabilistic Modeling: Preprint

    Yao, Yin; Gao, Wenzhong; Momoh, James; Muljadi, Eduard

    2016-02-11

    In this paper, an economic dispatch model with probabilistic modeling is developed for a microgrid. The electric power supply in a microgrid consists of conventional power plants and renewable energy power plants, such as wind and solar power plants. Because of the fluctuation in the output of solar and wind power plants, an empirical probabilistic model is developed to predict their hourly output. According to different characteristics of wind and solar power plants, the parameters for probabilistic distribution are further adjusted individually for both. On the other hand, with the growing trend in plug-in electric vehicles (PHEVs), an integrated microgrid system must also consider the impact of PHEVs. The charging loads from PHEVs as well as the discharging output via the vehicle-to-grid (V2G) method can greatly affect the economic dispatch for all of the micro energy sources in a microgrid. This paper presents an optimization method for economic dispatch in a microgrid considering conventional power plants, renewable power plants, and PHEVs. The simulation results reveal that PHEVs with V2G capability can be an indispensable supplement in a modern microgrid.

  10. Investigate Transient Behaviours and Select Appropriate Fault Protection Solutions of Uni-grounded AC Microgrids

    Duong Minh Bui

    2016-03-01

    Full Text Available Transient situations of a uni-grounded low-voltage AC microgrid are simulated in this paper, which include different fault tests and operation transition test between the grid-connected and islanded modes of the uni-grounded microgrid. Based on transient simulation results, available fault protection methods are proposed for the main and back-up protection of a uni-grounded AC microgrid. Main contributions of this paper are (i analysing transient responses of a typically uni-grounded lowvoltage AC microgrid from line-to-line, single line-to-ground, three-phase faults and a microgrid operation transition test; and (ii proposing available fault protection methods for uni-grounded AC microgrids, such as non-directional/directional overcurrent protection solutions, under/over voltage protection solutions, differential protection, voltage-restrained overcurrent protection, and other protection principles not based on high fault currents (e.g. total harmonic distortion detection of phase currents and voltages, or protection methods using symmetrical sequence components of current and voltage.

  11. A Generalised Fault Protection Structure Proposed for Uni-grounded Low-Voltage AC Microgrids

    Bui, Duong Minh; Chen, Shi-Lin; Lien, Keng-Yu; Jiang, Jheng-Lun

    2016-04-01

    This paper presents three main configurations of uni-grounded low-voltage AC microgrids. Transient situations of a uni-grounded low-voltage (LV) AC microgrid (MG) are simulated through various fault tests and operation transition tests between grid-connected and islanded modes. Based on transient simulation results, available fault protection methods are proposed for main and back-up protection of a uni-grounded AC microgrid. In addition, concept of a generalised fault protection structure of uni-grounded LVAC MGs is mentioned in the paper. As a result, main contributions of the paper are: (i) definition of different uni-grounded LVAC MG configurations; (ii) analysing transient responses of a uni-grounded LVAC microgrid through line-to-line faults, line-to-ground faults, three-phase faults and a microgrid operation transition test, (iii) proposing available fault protection methods for uni-grounded microgrids, such as: non-directional or directional overcurrent protection, under/over voltage protection, differential current protection, voltage-restrained overcurrent protection, and other fault protection principles not based on phase currents and voltages (e.g. total harmonic distortion detection of currents and voltages, using sequence components of current and voltage, 3I0 or 3V0 components), and (iv) developing a generalised fault protection structure with six individual protection zones to be suitable for different uni-grounded AC MG configurations.

  12. Optimal Bidding of a Microgrid Based on Probabilistic Analysis of Island Operation

    Siyoung Lee

    2016-10-01

    Full Text Available Island operation of a microgrid increases operation survivability and reliability when there is a large accident in a main grid. However, because a microgrid typically has limited generation capability, a microgrid operator (MGO has to take the risk of island operation into account in its market participation and generation scheduling to ensure efficient operation. In this paper, a microgrid islanding event is interpreted as a trade suspension of a contract, and a set of islanding rules is presented in the form of a market rule. The risk of island operation is evaluated by modeling the microgrid islanding stochastically using an islanding probability function, which is defined in the form of a conditional probability to reflect the influence of outside conditions. An optimal bidding strategy is obtained for the MGO by formulating and solving an optimization problem to minimize the expected operating cost. The effectiveness of the proposed method was investigated by numerical simulations in which the proposed method and two other methods were applied to the same microgrid. Numerical sensitivity analyses of the coefficients of the islanding probability function were conducted to determine how an MGO copes with changes in outside conditions.

  13. Life cycle energy and environmental analysis of a microgrid power pavilion

    Spitzley, David V.; Keoleian, Gregory A.; Baron, Scott G.

    2006-01-01

    Microgrids - generating systems incorporating multiple distributed generator sets linked together to provide local electricity and heat - are one possible alterative to the existing centralized energy system. Potential advantages of microgrids include flexibility in fuel supply options, the ability to limit emissions of greenhouse gases, and energy efficiency improvements through combined heat and power (CHP) applications. As a case study in microgrid performance, this analysis uses a life cycle assessment approach to evaluate the energy and emissions performance of the NextEnergy microgrid Power Pavilion in Detroit, Michigan and a reference conventional system. The microgrid includes generator sets fueled by solar energy, hydrogen, and natural gas. Hydrogen fuel is sourced from both a natural gas steam reforming operation and as a by-product of a chlorine production operation. The chlorine plant receives electricity exclusively from a hydropower generating station. Results indicate that the use of this microgrid offers a total energy reduction potential of up to 38%, while reductions in non-renewable energy use could reach 51%. Similarly, emissions of CO 2 , a key global warming gas, can be reduced by as much as 60% relative to conventional heat and power systems. Hydrogen fuels are shown to provide a net energy and emissions benefit relative to natural gas only when sourced primarily from the chlorine plant. (Author)

  14. Methodology for Monitoring Sustainable Development of Isolated Microgrids in Rural Communities

    Claudia Rahmann

    2016-11-01

    Full Text Available Microgrids are a rapidly evolving and increasingly common form of local power generation used to serve the needs of both rural and urban communities. In this paper, we present a methodology to evaluate the evolution of the sustainability of stand-alone microgrids projects. The proposed methodology considers a composite sustainability index (CSI that includes both positive and negative impacts of the operation of the microgrid in a given community. The CSI is constructed along environmental, social, economic and technical dimensions of the microgrid. The sub-indexes of each dimension are aggregated into the CSI via a set of adaptive weighting factors, which indicate the relative importance of the corresponding dimension in the sustainability goals. The proposed methodology aims to be a support instrument for policy makers especially when defining sound corrective measures to guarantee the sustainability of small, isolated microgrid projects. To validate the performance of the proposed methodology, a microgrid installed in the northern part of Chile (Huatacondo has been used as a benchmarking project.

  15. Series-Connected High Frequency Converters in a DC Microgrid System for DC Light Rail Transit

    Bor-Ren Lin

    2018-01-01

    Full Text Available This paper studies and presents a series-connected high frequency DC/DC converter connected to a DC microgrid system to provide auxiliary power for lighting, control and communication in a DC light rail vehicle. Three converters with low voltage and current stresses of power devices are series-connected with single transformers to convert a high voltage input to a low voltage output for a DC light rail vehicle. Thus, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs with a low voltage rating and a turn-on resistance are adopted in the proposed circuit topology in order to decrease power losses on power switches and copper losses on transformer windings. A duty cycle control with an asymmetric pulse-width modulation is adopted to control the output voltage at the desired voltage level. It is also adopted to reduce switching losses on MOSFETs due to the resonant behavior from a leakage inductor of an isolated transformer and output capacitor of MOSFETs at the turn-on instant. The feasibility and effectiveness of the proposed circuit have been verified by a laboratory prototype with a 760 V input and a 24 V/60 A output.

  16. Heuristic Approach for Configuration of a Grid-Tied Microgrid in Puerto Rico

    Rodriguez, Miguel A.

    The high rates of cost of electricity that consumers are being charged by the utility grid in Puerto Rico have created an energy crisis around the island. This situation is due to the island's dependence on imported fossil fuels. In order to aid in the transition from fossil-fuel based electricity into electricity from renewable and alternative sources, this research work focuses on reducing the cost of electricity for Puerto Rico through means of finding the optimal microgrid configuration for a set number of consumers from the residential sector. The Hybrid Optimization Modeling for Energy Renewables (HOMER) software, developed by NREL, is utilized as an aid in determining the optimal microgrid setting. The problem is also approached via convex optimization; specifically, an objective function C(t) is formulated in order to be minimized. The cost function depends on the energy supplied by the grid, the energy supplied by renewable sources, the energy not supplied due to outages, as well as any excess energy sold to the utility in a yearly manner. A term for considering the social cost of carbon is also considered in the cost function. Once the microgrid settings from HOMER are obtained, those are evaluated via the optimized function C( t), which will in turn assess the true optimality of the microgrid configuration. A microgrid to supply 10 consumers is considered; each consumer can possess a different microgrid configuration. The cost function C( t) is minimized, and the Net Present Value and Cost of Electricity are computed for each configuration, in order to assess the true feasibility. Results show that the greater the penetration of components into the microgrid, the greater the energy produced by the renewable sources in the microgrid, the greater the energy not supplied due to outages. The proposed method demonstrates that adding large amounts of renewable components in a microgrid does not necessarily translates into economic benefits for the consumer; in

  17. Demand response impacts on off-grid hybrid photovoltaic-diesel generator microgrids

    Aaron St. Leger

    2015-08-01

    Full Text Available Hybrid microgrids consisting of diesel generator set(s and converter based power sources, such as solar photovoltaic or wind sources, offer an alternative to generator based off-grid power systems. The hybrid approach has been shown to be economical in many off-grid applications and can result in reduced generator operation, fuel requirements, and maintenance. However, the intermittent nature of demand and renewable energy sources typically require energy storage, such as batteries, to properly operate the hybrid microgrid. These batteries increase the system cost, require proper operation and maintenance, and have been shown to be unreliable in case studies on hybrid microgrids. This work examines the impacts of leveraging demand response in a hybrid microgrid in lieu of energy storage. The study is performed by simulating two different hybrid diesel generator—PV microgrid topologies, one with a single diesel generator and one with multiple paralleled diesel generators, for a small residential neighborhood with varying levels of demand response. Various system designs are considered and the optimal design, based on cost of energy, is presented for each level of demand response. The solar resources, performance of solar PV source, performance of diesel generators, costs of system components, maintenance, and operation are modeled and simulated at a time interval of ten minutes over a twenty-five year period for both microgrid topologies. Results are quantified through cost of energy, diesel fuel requirements, and utilization of the energy sources under varying levels of demand response. The results indicate that a moderate level of demand response can have significant positive impacts to the operation of hybrid microgrids through reduced energy cost, fuel consumption, and increased utilization of PV sources.

  18. Optimal design of CHP-based microgrids: Multiobjective optimisation and life cycle assessment

    Zhang, Di; Evangelisti, Sara; Lettieri, Paola; Papageorgiou, Lazaros G.

    2015-01-01

    As an alternative to current centralised energy generation systems, microgrids are adopted to provide local energy with lower energy expenses and gas emissions by utilising distributed energy resources (DER). Several micro combined heat and power technologies have been developed recently for applications at domestic scale. The optimal design of DERs within CHP-based microgrids plays an important role in promoting the penetration of microgrid systems. In this work, the optimal design of microgrids with CHP units is addressed by coupling environmental and economic sustainability in a multi-objective optimisation model which integrates the results of a life cycle assessment of the microgrids investigated. The results show that the installation of multiple CHP technologies has a lower cost with higher environmental saving compared with the case when only a single technology is installed in each site, meaning that the microgrid works in a more efficient way when multiple technologies are selected. In general, proton exchange membrane (PEM) fuel cells are chosen as the basic CHP technology for most solutions, which offers lower environmental impacts at low cost. However, internal combustions engines (ICE) and Stirling engines (SE) are preferred if the heat demand is high. - Highlights: • Optimal design of microgrids is addressed by coupling environmental and economic aspects. • An MILP model is formulated based on the ε-constraint method. • The model selects a combination of CHP technologies with different technical characteristics for optimum scenarios. • The global warming potential (GWP) and the acidification potential (AP) are determined. • The output of LCA is used as an input for the optimisation model

  19. Dynamic stability analysis of microgrid by integrating transfer function of DERs

    Basak, Prasenjit [Calcutta Institute of Engineering & Management, Electrical Engineering Department, Kolkata (India); Chowdhury, S.; Chowdhury, S.P. [University of Cape Town, Electrical Engineering Department, Cape Town (South Africa)

    2010-07-01

    A microgrid is an integrated form of distributed energy resources (DERs) which are connected together to serve electrical power to the selected consumers or can exchange power with the existing utility grid suitably under standalone or grid connected mode. The microgrid can be cited as a physical system which is a combination of DERs such as, Photovoltaic Generator, Wind turbine, Fuel Cell, Microturbine etc. and can be modelled with suitable assumptions depending upon specific operational condition to be studied. Interconnection of several kinds of power sources would impact the quality of power within the microgrid. Since voltage and frequency are not the only factors for a system delivering good quality power, the capacity of the same to withstand instability due to transient condition is one of the prime factors to be considered to accept a system as a stable system. Before practical integration of distributed energy resources, it would be essential to check the stability of the system at the design stage. In this paper, the authors have presented the microgrid based on control system engineering. To represent the individual components of microgrid, the DERs (Distributed Energy Resources) have been represented with their transfer functions and they have been simulated using Simulink-Matlab. To observe the response of the DERs, the frequency fluctuation due to step and random change in output power/load are considered as the main factors for stability analysis. All the DERs are integrated forming the microgrid which is represented with an equivalent transfer function based model. The models are studied and results are discussed with the waveforms. This paper shows one feasible method to check the dynamic stability of a proposed microgrid.

  20. A Novel Decentralized Economic Operation in Islanded AC Microgrids

    Hua Han

    2017-06-01

    Full Text Available Droop schemes are usually applied to the control of distributed generators (DGs in microgrids (MGs to realize proportional power sharing. The objective might, however, not suit MGs well for economic reasons. Addressing that issue, this paper proposes an alternative droop scheme for reducing the total active generation costs (TAGC. Optimal economic operation, DGs’ capacity limitations and system stability are fully considered basing on DGs’ generation costs. The proposed scheme utilizes the frequency as a carrier to realize the decentralized economic operation of MGs without communication links. Moreover, a fitting method is applied to balance DGs’ synchronous operation and economy. The effectiveness and performance of the proposed scheme are verified through simulations and experiments.