Interconnection Guidelines

Science.gov (United States)

The Interconnection Guidelines provide general guidance on the steps involved with connecting biogas recovery systems to the utility electrical power grid. Interconnection best practices including time and cost estimates are discussed.

Grid-connected photovoltaic power systems: survey of inverter and related protection equipments

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, T

2002-12-15

This report for the International Energy Agency (IEA) made by Task 5 of the Photovoltaic Power Systems (PVPS) programme reports on a survey made on inverter and related protection equipment. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. Task 5 deals with issues concerning grid-interconnection and distributed PV power systems. This report summarises the data obtained from survey of recent inverter technology and inverter protection equipment for grid interconnected PV systems. The results are based on the surveys using a questionnaire to identify the current status of grid-interconnection inverters. This report is to serve as a reference for those interested in installing grid-connected PV systems, electric utility company personnel, manufacturers and researchers. The results of the survey are presented and discussed. Technical and financial data is reviewed and two appendices provide details on the results obtained and those institutions involved in the survey.

Report on technological survey in fiscal 1999. Demonstration test for smoothing grid interconnection (Collection of information by surveys in overseas countries); 1999 nendo keito renkei enkatsuka jissho shiken chosa hokokusho. Kaigai chosa ni yoru joho shushu

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Surveys were performed on the institutional aspects of establishment and operation of grid interconnection guidelines in the countries advanced in introduction of discrete power supply systems. The survey items for America include: (1) summary of the status related to grid interconnection, (2) grid interconnection process, (3) methods for paying expenses for increasing power transmission facilities by means of grid interconnection, (4) dispute processing, (5) information release, and (6) software. The survey items for England, Germany, and France include: (1) summary of electricity business, (2) regulation patterns in electricity business, (3) summary of grid operating organizations, (4) connection to grid interconnection systems, and (5) the future liberalization programs. America is establishing standards for grid interconnection in discrete power supplies including photovoltaic power generation and energy storage under SCC21 of IEEE, whose conclusion will be drawn in the end of 2000. The Energy Department has an intention to give the standards the legal bases to operate them under unified requirements. Germany, England and France have all established standards for operating the grid interconnection. Market liberalization for electric power retailing is advancing in the order of America, England, Germany, and France. (NEDO)

A GRID-CONNECTED HYBRID WIND-SOLAR POWER SYSTEM

Directory of Open Access Journals (Sweden)

MAAMAR TALEB

2017-06-01

Full Text Available A hybrid renewable energy system consisting of a photovoltaic generator and a wind driven DC machine is interconnected with the power utilities grid. The interconnection is done through the use of two separate single phase full wave controlled bridge converters. The bridge converters are operated in the “inverter mode of operation”. That is to guaranty the extraction of the real powers from the wind driven generator as well as from the photovoltaic generator and inject them into the power utilities grid. At any pretended surrounding weather conditions, maximum extraction of powers from both renewable energy sources is targeted. This is done through the realization of self-adjusted firing angle controllers responsible of triggering the semiconductor elements of the controlled converters. An active power filter is shunted with the proposed setup to guaranty the sinusoid quality of the power utilities line current. The overall performance of the proposed system has been simulated in MATLAB/SIMULINK environment. Quite satisfactory and encouraging results have been obtained.

Innovative Distributed Power Grid Interconnection and Control Systems: Final Report, December 11, 2000 - August 30, 2005

Energy Technology Data Exchange (ETDEWEB)

DePodesta, K.; Birlingmair, D.; West, R.

2006-03-01

The contract goal was to further advance distributed generation in the marketplace by making installations more cost-effective and compatible with existing systems. This was achieved by developing innovative grid interconnection and control systems.

Task 5. Grid interconnection of building integrated and other dispersed photovoltaic power systems. International guideline for the certification of photovoltaic system components and grid-connected systems

Energy Technology Data Exchange (ETDEWEB)

Bower, W.

2002-02-15

This report for the International Energy Agency (IEA) made by Task 5 of the Photovoltaic Power Systems (PVPS) programme presents a guideline for the certification of photovoltaic system components and grid-connected systems. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. Task 5 deals with issues concerning grid-interconnection and distributed PV power systems. This generic international guideline for the certification of photovoltaic system components and complete grid-connected photovoltaic systems describes a set of recommended methods and tests that may be used to verify the integrity of hardware and installations, compliance with applicable standards/codes and can be used to provide a measure of the performance of components or of entire systems. The guideline is to help ensure that photovoltaic installations are both safe for equipment as well as for personnel when used according to the applicable installation standards and codes. The guideline may be used in any country using the rules stipulated by the applicable standards and codes and by applying them to the guideline's recommended tests. This document uses examples for some tests but does not specify exact test set-ups, equipment accuracy, equipment manufacturers or calibration procedures.

Grid Monitoring and Advanced Control of Distributed Power Generation Systems

DEFF Research Database (Denmark)

Timbus, Adrian Vasile

. As an example, the latest published grid codes stress the ability of distributed generators, especially wind turbines, to stay connected during short grid disturbances and in addition to provide active/reactive power control at the point of common coupling. Based on the above facts, the need for improving...... reported in some countries creating concerns about power system stability. This leads to a continuous evolution of grid interconnection requirements towards a better controllability of generated power and an enhanced contribution of distributed power generation systems to power system stability...... and adding more features to the control of distributed power generation systems (DPGS) arises. As a consequence, this thesis focuses on grid monitoring methods and possible approaches in control in order to obtain a more reliable and  exible power generation system during normal and faulty grid conditions...

Maghreb: from the interconnection of power grids to energetic integration. Energy supply in Maghreb

International Nuclear Information System (INIS)

Keramane, Abdelnour

2015-10-01

In a first article, the author first comments the levels of electricity production and consumption in Maghreb, and how this production is distributed among different sources in Algeria, Morocco and Tunisia. He comments how electric power utilities in these countries decided to collaborate to create common bodies and to implement an interconnection between their power grids, but also with Libya and Spain. He outlines that the three countries aim at creating a common Maghreb market of electricity and then at being integrated into the European market. The author then discusses the planned evolution of the energy mix, and more particularly the role different energies (hydrocarbons, coal, nuclear, renewable energies) may have in the future. He finally discusses the challenges and issues associated with a passage from collaboration to integration. In the second article, the author proposes an overview of energy supply in Algeria, Morocco and Tunisia. He comments data related to primary energy consumption, to the prevalence of fossil energies, to the marginal share of renewable energies, to energy efficiency, and to carbon footprint. For some of these issues, data are given for 2000 and 2011, for each country, for the three countries together and for the world. The author comments trends, evolutions and perspectives for the different energy resources: hydrocarbons and renewable sources

Biography of a technology: North America's power grid through the twentieth century

Science.gov (United States)

Cohn, Julie A.

North Americans are among the world's most intense consumers of electricity. The vast majority in the United States and Canada access power from a network of transmission lines that stretch from the East Coast to the West Coast and from Canada to the Mexican Baja. This network, known as the largest interconnected machine in the world, evolved during the first two thirds of the twentieth century. With the very first link-ups occurring at the end of the 1890s, a wide variety of public and private utilities extended power lines to reach markets, access and manage energy resources, balance loads, realize economies of scale, provide backup power, and achieve economic stability. In 1967, utility managers and the Bureau of Reclamation connected the expansive eastern and western power pools to create the North American grid. Unlike other power grids around the world, built by single, centrally controlled entities, this large technological system emerged as the result of multiple decisions across eighty-five years of development, and negotiations for control at the economic, political, and technological levels. This dissertation describes the process of building the North American grid and the paradoxes the resulting system represents. While the grid functions as a single machine moving electricity across the continent, it is owned by many independent entities. Smooth operations suggest that the grid is a unified system; however, it operates under shared management and divided authority. In addition, although a single power network seems the logical outcome of electrification, in fact it was assembled through aggregation, not planning. Interconnections intentionally increase the robustness of individual sub-networks, yet the system itself is fragile, as demonstrated by major cascading power outages. Finally, the transmission network facilitates increased use of energy resources and consumption of power, but at certain points in the past, it also served as a technology of

MATL : Canada's first merchant power transmission interconnection : experiences and future outlook

International Nuclear Information System (INIS)

Wilson, L.

2006-01-01

The current status of the Montana Alberta Tie Ltd. (MATL) merchant transmission project was outlined with reference to the business concept, the advantages of the project and market opportunities. Some of the challenges facing the project were discussed along with lessons learned and accomplishments thus far. MATL is preparing to construct a privately funded transmission line between Lethbridge, Alberta and Great Falls, Montana. The project represents the first direct power transmission inter-connection between Montana and Alberta. The 346 km, 230 kV AC transmission line with phase shifting transformer and 300 MW transfer capacity will be a synchronous interconnection and will improve the reliability of the entire electric systems in both Montana and Alberta. The benefits of the interconnected power system include increased reliability and stability of the existing power grids; better import/export capabilities; more competition and options in the marketplace; greater flexibility in scheduling generator maintenance; and, optimal allocation of generation resources. tabs., figs

Development of Innovative Distributed Power Interconnection and Control Systems: Annual Report, December 2000-December 2001

Energy Technology Data Exchange (ETDEWEB)

Liss, W.; Dybel, M.; West, R.; Adams, L.

2002-11-01

This report covers the first year's work performed by the Gas Technology Institute and Encorp Inc. under subcontract to the National Renewable Energy Laboratory. The objective of this three-year contract is to develop innovative grid interconnection and control systems. This supports the advancement of distributed generation in the marketplace by making installations more cost-effective and compatible across the electric power and energy management systems. Specifically, the goals are: (1) To develop and demonstrate cost-effective distributed power grid interconnection products and software and communication solutions applicable to improving the economics of a broad range of distributed power systems, including existing, emerging, and other power generation technologies. (2) To enhance the features and capabilities of distributed power products to integrate, interact, and provide operational benefits to the electric power and advanced energy management systems. This includes features and capabilities for participating in resource planning, the provision of ancillary services, and energy management. Specific topics of this report include the development of an advanced controller, a power sensing board, expanded communication capabilities, a revenue-grade meter interface, and a case study of an interconnection distributed power system application that is a model for demonstrating the functionalities of the design of the advanced controller.

Value of Improved Wind Power Forecasting in the Western Interconnection (Poster)

Energy Technology Data Exchange (ETDEWEB)

Hodge, B.

2013-12-01

Wind power forecasting is a necessary and important technology for incorporating wind power into the unit commitment and dispatch process. It is expected to become increasingly important with higher renewable energy penetration rates and progress toward the smart grid. There is consensus that wind power forecasting can help utility operations with increasing wind power penetration; however, there is far from a consensus about the economic value of improved forecasts. This work explores the value of improved wind power forecasting in the Western Interconnection of the United States.

Inverter for Interchangeable Use as Current Source Inverter and Voltage Source Inverter for Interconnecting to Grid

Science.gov (United States)

Teruya, Daisuke; Masukawa, Shigeo; Iida, Shoji

We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.

Low power interconnect design

CERN Document Server

Saini, Sandeep

2015-01-01

This book provides practical solutions for delay and power reduction for on-chip interconnects and buses.  It provides an in depth description of the problem of signal delay and extra power consumption, possible solutions for delay and glitch removal, while considering the power reduction of the total system.  Coverage focuses on use of the Schmitt Trigger as an alternative approach to buffer insertion for delay and power reduction in VLSI interconnects. In the last section of the book, various bus coding techniques are discussed to minimize delay and power in address and data buses.   ·         Provides practical solutions for delay and power reduction for on-chip interconnects and buses; ·         Focuses on Deep Sub micron technology devices and interconnects; ·         Offers in depth analysis of delay, including details regarding crosstalk and parasitics;  ·         Describes use of the Schmitt Trigger as a versatile alternative approach to buffer insertion for del...

Designing for Wide-Area Situation Awareness in Future Power Grid Operations

Science.gov (United States)

Tran, Fiona F.

Power grid operation uncertainty and complexity continue to increase with the rise of electricity market deregulation, renewable generation, and interconnectedness between multiple jurisdictions. Human operators need appropriate wide-area visualizations to help them monitor system status to ensure reliable operation of the interconnected power grid. We observed transmission operations at a control centre, conducted critical incident interviews, and led focus group sessions with operators. The results informed a Work Domain Analysis of power grid operations, which in turn informed an Ecological Interface Design concept for wide-area monitoring. I validated design concepts through tabletop discussions and a usability evaluation with operators, earning a mean System Usability Scale score of 77 out of 90. The design concepts aim to support an operator's complete and accurate understanding of the power grid state, which operators increasingly require due to the critical nature of power grid infrastructure and growing sources of system uncertainty.

An Examination of AC/HVDC Power Circuits for Interconnecting Bulk Wind Generation with the Electric Grid

Directory of Open Access Journals (Sweden)

Daniel Ludois

2010-06-01

Full Text Available The application of high voltage dc (HVDC transmission for integrating large scale and/or off-shore wind generation systems with the electric grid is attractive in comparison to extra high voltage (EHV ac transmission due to a variety of reasons. While the technology of classical current sourced converters (CSC using thyristors is well established for realization of large HVDC systems, the technology of voltage sourced converters (VSC is emerging to be an alternative approach, particularly suitable for multi-terminal interconnections. More recently, a more modular scheme that may be termed ‘bridge of bridge’ converters (BoBC has been introduced to realize HVDC systems. While all these three approaches are functionally capable of realizing HVDC systems, the converter power circuit design trade-offs between these alternatives are not readily apparent. This paper presents an examination of these topologies from the point of view of power semiconductor requirements, reactive component requirements, operating losses, fault tolerance, multi-terminal operation, modularity, complexity, etc. Detailed analytical models will be used along with a benchmark application to develop a comparative evaluation of the alternatives that maybe used by wind energy/bulk transmission developers for performing engineering trade-off studies.

Simplified reactive power management strategy for complex power grids under stochastic operation and incomplete information

International Nuclear Information System (INIS)

Vlachogiannis, John G.

2009-01-01

In the current released energy market, the large-scale complex transmission networks and the distribution ones with dispersed energy sources and 'intelligent' components operate under uncertainties, stochastic and prior incomplete information. A safe and reliable operation of such complex power grids is a major issue for system operators. Under these circumstances an online reactive power management strategy with minimum risk concerning all uncertain and stochastic parameters is proposed. Therefore, new concepts such as reactive power-weighted node-to-node linking and reactive power control capability are introduced. A distributed and interconnected stochastic learning automata system is implemented to manage, in a unified and unique way, the reactive power in complex power grids with stochastic reactive power demand and detect the vulnerable part. The proposed simplified strategy can also consider more stochastic aspects such as variable grid's topology. Results of the proposed strategy obtained on the networks of IEEE 30-bus and IEEE 118-bus systems demonstrate the effectiveness of the proposed strategy.

Grid-connected photovoltaic power systems. Technical and potential problems. A review

International Nuclear Information System (INIS)

Eltawil, Mohamed A.; Zhao, Zhengming

2010-01-01

Traditional electric power systems are designed in large part to utilize large baseload power plants, with limited ability to rapidly ramp output or reduce output below a certain level. The increase in demand variability created by intermittent sources such as photovoltaic (PV) presents new challenges to increase system flexibility. This paper aims to investigate and emphasize the importance of the grid-connected PV system regarding the intermittent nature of renewable generation, and the characterization of PV generation with regard to grid code compliance. The investigation was conducted to critically review the literature on expected potential problems associated with high penetration levels and islanding prevention methods of grid tied PV. According to the survey, PV grid connection inverters have fairly good performance. They have high conversion efficiency and power factor exceeding 90% for wide operating range, while maintaining current harmonics THD less than 5%. Numerous large-scale projects are currently being commissioned, with more planned for the near future. Prices of both PV and balance of system components (BOS) are decreasing which will lead to further increase in use. The technical requirements from the utility power system side need to be satisfied to ensure the safety of the PV installer and the reliability of the utility grid. Identifying the technical requirements for grid interconnection and solving the interconnect problems such as islanding detection, harmonic distortion requirements and electromagnetic interference are therefore very important issues for widespread application of PV systems. The control circuit also provides sufficient control and protection functions like maximum power tracking, inverter current control and power factor control. Reliability, life span and maintenance needs should be certified through the long-term operation of PV system. Further reduction of cost, size and weight is required for more utilization of PV

Environmental benefits of electricity grid interconnections in Northeast Asia

International Nuclear Information System (INIS)

Streets, D.G.

2003-01-01

From an environmental perspective, electricity grid interconnections in Northeast Asia make sense. Cities in Northeast China, Mongolia, the Democratic People's Republic of Korea (DPRK), and the Republic of Korea (ROK) suffer from poor air quality due to the extensive use of coal-fired power generation. Rural communities suffer from a deficit of electricity, forcing reliance on coal and biofuels for cooking and heating in the home, which causes health-damaging indoor air pollution. Regional air pollution from acid rain and ozone is widespread. In addition, Japan is finding it hard to meet its commitment under the Kyoto Protocol. Yet, just across their borders in far eastern Russia are extensive, clean energy resources: hydroelectricity and natural gas, and (potentially) nuclear power and tidal power. It would be environmentally beneficial to generate electricity cleanly in far eastern Russia and transmit the electricity across the borders into China, Mongolia, the DPRK, the ROK, and Japan, thereby displacing coal-fired electricity generation. We estimate that currently planned projects could alleviate the problems of two to five Chinese cities, with the potential for much larger benefits in the future. (author)

A Distributed Robust Dispatch Approach for Interconnected Systems with a High Proportion of Wind Power Penetration

Directory of Open Access Journals (Sweden)

Jianwen Ren

2018-04-01

Full Text Available This paper proposes a distributed robust dispatch approach to solve the economic dispatch problem of the interconnected systems with a high proportion of wind power penetration. First of all, the basic principle of synchronous alternating direction method of multipliers (SADMM is introduced to solve the economic dispatch problem of the two interconnected regions. Next, the polyhedron set of the robust optimization method is utilized to describe the wind power output. To adjust the conservativeness of the polyhedron set, an adjustment factor of robust conservativeness is introduced. Subsequently, considering the operation characteristics of the DC tie line between the interconnected regions, an economic dispatch model with a high proportion of wind power penetration is established and parallel iteration based on SADMM is used to solve the model. In each iteration, the optimized power of DC tie lines is exchanged between the regions without requiring the participation of the superior dispatch center. Finally, the validity of the proposed model is verified by the examples of the 2-area 6-node interconnected system and the interconnection of several modified New England 39-node systems. The results show that the proposed model can meet the needs of the independent dispatch of regional power grids, effectively deal with the uncertainty of wind power output, and maximize the wind power consumption under the condition of ensuring the safe operation of the interconnected systems.

The Prospect for an Australian–Asian Power Grid: A Critical Appraisal

Directory of Open Access Journals (Sweden)

Edward Halawa

2018-01-01

Full Text Available Australia is an energy net self-sufficient country rich in energy resources, from fossil-based to renewable energy. Australia, a huge continent with low population density, has witnessed impressive reduction in energy consumption in various sectors of activity in recent years. Currently, coal and natural gas are two of Australia’s major export earners, yet its abundant renewable energy resources such as solar, wind, and tidal, are still underutilized. The majority of Asian countries, on the other hand, are in the middle of economic expansion, with increasing energy consumption and lack of energy resources or lack of energy exploration capability becoming a serious challenge. Electricity interconnection linking two or more independent grids within a country or at cross-border or regional levels has found its way into electricity markets worldwide. This concept allows for electricity exchanges that lead to optimized use and sharing of electricity generated from different sources. The interconnection also enables the long distance exploitation of renewable energy which would otherwise be physically impossible. ASEAN (Association of Southeast Asian Nations and other regional groupings in Asia have initiated a number of interconnections to gain economic benefits. Asian’s hunger for energy for its economic development, climate change that has become a global and urgent issue to be solved, and Australia’s abundant renewable energy resources have all prompted increasing interest in a super-grid interconnection linking Australia to Asian grids, the Australian–Asian (Power Grid (AAG. This paper overviews the existing grid interconnections as well as current initiatives at domestic, sub-regional, and regional levels worldwide, with a particular focus on Asia. The paper concludes with a critical appraisal on the benefits, potential, challenges and issues to be encountered by the AAG initiative.

Task 5. Grid interconnection of building integrated and other dispersed photovoltaic power systems. Risk analysis of islanding of photovoltaic power systems within low voltage distribution networks

Energy Technology Data Exchange (ETDEWEB)

Cullen, N. [Freelance Consultant, Hillside House, Swindon SN1 3QA (United Kingdom); Thornycroft, J. [Halcrow Group Ltd, Burderop Park, Swindon SN4 0QD (United Kingdom); Collinson, A. [EA Technology, Capenhurst Technology Park, Chester CH1 6ES (United Kingdom)

2002-03-15

This report for the International Energy Agency (IEA) made by Task 5 of the Photovoltaic Power Systems (PVPS) programme presents the results of a risk analysis concerning photovoltaic power systems islanding in low-voltage distribution networks. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. Task 5 deals with issues concerning grid-interconnection and distributed PV power systems. The purpose of this study was to apply formal risk analysis techniques to the issue of islanding of photovoltaic power systems within low voltage distribution networks. The aim was to determine the additional level of risk that islanding could present to the safety of customers and network maintenance staff. The study identified the reliability required for islanding detection and control systems based on standard procedures for developing a safety assurance strategy. The main conclusions are presented and discussed and recommendations are made. The report is concluded with an appendix that lists the relative risks involved.

Simplified reactive power management strategy for complex power grids under stochastic operation and incomplete information

DEFF Research Database (Denmark)

Vlachogiannis, Ioannis (John)

2009-01-01

grids is a major issue for system operators. Under these circumstances an online reactive power management strategy with minimum risk concerning all uncertain and stochastic parameters is proposed. Therefore, new concepts such as reactive power-weighted node-to-node linking and reactive power control......In the current released energy market, the large-scale complex transmission networks and the distribution ones with dispersed energy sources and "intelligent" components operate under uncertainties, stochastic and prior incomplete information. A safe and reliable operation of such complex power...... capability are introduced. A distributed and interconnected stochastic learning automata system is implemented to manage, in a unified and unique way, the reactive power in complex power grids with stochastic reactive power demand and detect the vulnerable part. The proposed simplified strategy can also...

Report on technological survey in fiscal 1998. Demonstration test for smoothing grid interconnection (Collection of information by surveys in overseas countries); 1998 nendo keito renkei enkatsuka jissho shiken chosa hokokusho. Kaigai chosa ni yoru joho shushu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

Surveys were performed on the institutional aspects of establishment and operation of grid interconnection guidelines in the countries advanced in introduction of discrete power supply systems, namely, England, Ireland, Italy and the United States, as well as on the simulation technologies to realize them technically. In England, the power transmission systems (controller: NGO) and the power distribution systems (controller: PES) are separated, to which grid interconnection operating regulations are provided respectively. Single operation of generators connected to the power distribution system is not permitted substantially. In Ireland, the power transmission and distribution functions are separated, but are in the transition stage. Interconnection, if requested, cannot be rejected except for a case that the interconnection is impossible. Italy has the condition similar to that in Ireland, where no small generators are not permitted of independent operation. America has not unified the operating regulations for grid interconnection, and has apprehension in the independent operation, but no countermeasures have been given. In the simulation technologies, surveys were made on PSS/E, EUROSTAG, and SICRE. The PSS/E is the standard software in America for the current and stability analysis. (NEDO)

Making connections: Case studies of interconnection barriers and their impact on distributed power projects

Energy Technology Data Exchange (ETDEWEB)

Alderfer, B.; Eldridge, M.; Starrs, T.

2000-07-25

Distributed power is modular electric generation or storage located close to the point of use. Based on interviews of distributed generation project proponents, this report reviews the barriers that distributed generators of electricity are encountering when attempting to interconnect to the electrical grid. Descriptions of 26 of 65 case studies are included in the report. The survey found and the report describes a wide range of technical, business-practice, and regulatory barriers to interconnection. An action plan for reducing the impact of these barriers is also included.

Study on application of a high-speed trigger-type SFCL (TSFCL) for interconnection of power systems with different reliabilities

International Nuclear Information System (INIS)

Kim, Hye Ji; Yoon, Yong Tae

2016-01-01

Highlights: • Application of TSFCL to interconnect systems with different reliabilities is proposed. • TSFCL protects a grid by preventing detrimental effects from being delivered through the interconnection line. • A high-speed TSFCL with high impedance for transmission systems is required to be developed. - Abstract: Interconnection of power systems is one effective way to improve power supply reliability. However, differences in the reliability of each power system create a greater obstacle for the stable interconnection of power systems, as after interconnection a high-reliability system is affected by frequent faults in low reliability side systems. Several power system interconnection methods, such as the back-to-back method and the installation of either transformers or series reactors, have been investigated to counteract the damage caused by faults in the other neighboring systems. However, these methods are uneconomical and require complex operational management plans. In this work, a high-speed trigger-type superconducting fault current limiter (TSFCL) with large-impedance is proposed as a solution to maintain reliability and power quality when a high reliability power system is interconnected with a low reliability power system. Through analysis of the reliability index for the numerical examples obtained from a PSCAD/EMTDC simulator, a high-speed TSFCL with a large-impedance is confirmed to be effective for the interconnection between power systems with different reliabilities.

Issues and prospects in opting for new off-grid in favor to grid-integrated wind power generation systems : the case of Ethiopia

Energy Technology Data Exchange (ETDEWEB)

Wolde-Ghiorgis, W. [Addis Ababa Univ., Addis Ababa (Ethiopia). Dept. of Electrical and Computer Engineering

2008-07-01

This presentation addressed issues and prospects that help resolve constraints facing wind energy development in developing countries, with particular reference to on grid-integrated, and possibly off-grid power generation. The limitations to wind energy-development include a lack of a sizable and interconnected grids and a lack of financing. As such, even if harnessable wind energy potential is discovered at conveniently located inland sites, producing electricity would still be a challenge. This is the situation faced by less developed countries such as Ethiopia where the population and energy demands are increasing. There are also additional constraints to be addressed, recognized and resolved. This paper demonstrated that the use of clean development mechanisms (CDM) could attract support from interested industrialized countries to initiate off-grid wind power generation schemes. Off-grid wind power generation is considered to be a viable option for CDM financing. Cost comparisons and operational safety favour off-grid wind power generation. 5 refs., 3 tabs.

Comparative analysis of existing models for power-grid synchronization

International Nuclear Information System (INIS)

Nishikawa, Takashi; Motter, Adilson E

2015-01-01

The dynamics of power-grid networks is becoming an increasingly active area of research within the physics and network science communities. The results from such studies are typically insightful and illustrative, but are often based on simplifying assumptions that can be either difficult to assess or not fully justified for realistic applications. Here we perform a comprehensive comparative analysis of three leading models recently used to study synchronization dynamics in power-grid networks—a fundamental problem of practical significance given that frequency synchronization of all power generators in the same interconnection is a necessary condition for a power grid to operate. We show that each of these models can be derived from first principles within a common framework based on the classical model of a generator, thereby clarifying all assumptions involved. This framework allows us to view power grids as complex networks of coupled second-order phase oscillators with both forcing and damping terms. Using simple illustrative examples, test systems, and real power-grid datasets, we study the inherent frequencies of the oscillators as well as their coupling structure, comparing across the different models. We demonstrate, in particular, that if the network structure is not homogeneous, generators with identical parameters need to be modeled as non-identical oscillators in general. We also discuss an approach to estimate the required (dynamical) system parameters that are unavailable in typical power-grid datasets, their use for computing the constants of each of the three models, and an open-source MATLAB toolbox that we provide for these computations. (paper)

Security analysis of interconnected AC/DC systems

DEFF Research Database (Denmark)

Eriksson, Robert

2015-01-01

This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid...... any line or transformer limits. Simulations were performed in a model of the Nordic power system where a dc grid is placed on top. The simulation supports the method as a tool to consider transfer limits in the grid to avoid violate the same and increase the security after a converter outage........ The redistribution of power has a sudden effect on the power-flow in the interconnected ac system. This may cause overloading of lines and transformers resulting in disconnection of equipment, and as a consequence cascading failure. The PTDF is used as a method to analyze and avoid violating limits by in the dc...

The role of electric grids in the European energy policy. Grids development is necessary to supply cleaner and securer electric power

International Nuclear Information System (INIS)

Merlin, A.

2009-01-01

The world is actually entering a new energy era where CO 2 emissions must be reduced. Consequently, the European Union policy includes three goals: a) to reduce greenhouse gas emissions and fossil energy consumption; b) to improve the security of energy supply; c) to improve interconnection between regions. In this context, electrical grids play a strategic role. While the overall energy consumption in Europe will decrease, the electricity demand will increase by more than 1% per year. A large part of this increase will be covered by renewable energy sources, especially wind energy. In 2020 the total wind power installed in Europe should be ∼1000 GW, leading to a mean power production of 200-250 GW. This makes necessary an adaptation of electrical grids in order to be able to integrate into the system large power sources of intermittent character, and also to improve the solidarity of the different countries. The interconnection of the grids must be improved in order to balance electricity supply and demand. For the transport of electricity over large distances, developments will take place in three different areas; a) high voltage alternative current for most of the grids; b) high voltage direct current where it is necessary to overpass obstacles (mountains, sounds); c) gaseous insulation technology for underground transport. Local (mostly low voltage) grids must also be adapted: so far, they only carry electricity in one direction, to the customers. With the distributed power production, electricity transport in the reverse direction must also be considered

Development of a thin film solar cell interconnect for the PowerSphere concept

International Nuclear Information System (INIS)

Simburger, Edward J.; Matsumoto, James H.; Giants, Thomas W.; Garcia, Alexander; Liu, Simon; Rawal, Suraj P.; Perry, Alan R.; Marshall, Craig H.; Lin, John K.; Scarborough, Stephen E.; Curtis, Henry B.; Kerslake, Thomas W.; Peterson, Todd T.

2005-01-01

Progressive development of microsatellite technologies has resulted in increased demand for lightweight electrical power subsystems including solar arrays. The use of thin film photovoltaics has been recognized as a key solution to meet the power needs. The lightweight cells can generate sufficient power and still meet critical mass requirements. Commercially available solar cells produced on lightweight substrates are being studied as an option to fulfill the power needs. The commercially available solar cells are relatively inexpensive and have a high payoff potential. Commercially available thin film solar cells are primarily being produced for terrestrial applications. The need to convert the solar cell from a terrestrial to a space compatible application is the primary challenge. Solar cell contacts, grids and interconnects need to be designed to be atomic oxygen resistant and withstand rapid thermal cycling environments. A mechanically robust solar cell interconnect is also required in order to withstand handling during fabrication and survive during launch. The need to produce the solar cell interconnects has been identified as a primary goal of the PowerSphere program and is the topic of this paper. Details of the trade study leading to the final design involving the solar cell wrap around contact, flex blanket, welding process, and frame will be presented at the conference

Design of a nonlinear backstepping control strategy of grid interconnected wind power system based PMSG

Science.gov (United States)

Errami, Y.; Obbadi, A.; Sahnoun, S.; Benhmida, M.; Ouassaid, M.; Maaroufi, M.

2016-07-01

This paper presents nonlinear backstepping control for Wind Power Generation System (WPGS) based Permanent Magnet Synchronous Generator (PMSG) and connected to utility grid. The block diagram of the WPGS with PMSG and the grid side back-to-back converter is established with the dq frame of axes. This control scheme emphasises the regulation of the dc-link voltage and the control of the power factor at changing wind speed. Besides, in the proposed control strategy of WPGS, Maximum Power Point Tracking (MPPT) technique and pitch control are provided. The stability of the regulators is assured by employing Lyapunov analysis. The proposed control strategy for the system has been validated by MATLAB simulations under varying wind velocity and the grid fault condition. In addition, a comparison of simulation results based on the proposed Backstepping strategy and conventional Vector Control is provided.

Effect of Tower Shadow and Wind Shear in a Wind Farm on AC Tie-Line Power Oscillations of Interconnected Power Systems

DEFF Research Database (Denmark)

Tan, Jin; Hu, Weihao; Wang, Xiaoru

2013-01-01

This paper describes a frequency domain approach for evaluating the impact of tower shadow and wind shear effects (TSWS) on tie-line power oscillations. A simplified frequency domain model of an interconnected power system with a wind farm is developed. The transfer function, which relates the tie......-line power variation to the mechanical power variation of a wind turbine, and the expression of the maximum magnitude of tie-line power oscillations are derived to identify the resonant condition and evaluate the potential risk. The effects of the parameters on the resonant magnitude of the tie-line power...... are also discussed. The frequency domain analysis reveals that TSWS can excite large tie-line power oscillations if the frequency of TSWS approaches the tie-line resonant frequency, especially in the case that the wind farm is integrated into a relatively small grid and the tie-line of the interconnected...

Integrated assessment of water-power grid systems under changing climate

Science.gov (United States)

Yan, E.; Zhou, Z.; Betrie, G.

2017-12-01

Energy and water systems are intrinsically interconnected. Due to an increase in climate variability and extreme weather events, interdependency between these two systems has been recently intensified resulting significant impacts on both systems and energy output. To address this challenge, an Integrated Water-Energy Systems Assessment Framework (IWESAF) is being developed to integrate multiple existing or developed models from various sectors. In this presentation, we are focusing on recent improvement in model development of thermoelectric power plant water use simulator, power grid operation and cost optimization model, and model integration that facilitate interaction among water and electricity generation under extreme climate events. A process based thermoelectric power water use simulator includes heat-balance, climate, and cooling system modules that account for power plant characteristics, fuel types, and cooling technology. The model is validated with more than 800 power plants of fossil-fired, nuclear and gas-turbine power plants with different cooling systems. The power grid operation and cost optimization model was implemented for a selected regional in the Midwest. The case study will be demonstrated to evaluate the sensitivity and resilience of thermoelectricity generation and power grid under various climate and hydrologic extremes and potential economic consequences.

Comparison of Standards and Technical Requirements of Grid-Connected Wind Power Plants in China and the United States

Energy Technology Data Exchange (ETDEWEB)

Gao, David Wenzhong [Alternative Power Innovations, LLC; Muljadi, Eduard [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tian, Tian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, Mackay [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wang, Weisheng [China Electric Power Research Inst. (China)

2016-09-01

The rapid deployment of wind power has made grid integration and operational issues focal points in industry discussions and research. Compliance with grid connection standards for wind power plants (WPPs) is crucial to ensuring the reliable and stable operation of the electric power grid. This report compares the standards for grid-connected WPPs in China to those in the United States to facilitate further improvements in wind power standards and enhance the development of wind power equipment. Detailed analyses of power quality, low-voltage ride-through capability, active power control, reactive power control, voltage control, and wind power forecasting are provided to enhance the understanding of grid codes in the two largest markets of wind power. This study compares WPP interconnection standards and technical requirements in China to those in the United States.

Distributed Energy Resources Interconnection Systems: Technology Review and Research Needs

Energy Technology Data Exchange (ETDEWEB)

Friedman, N. R.

2002-09-01

Interconnecting distributed energy resources (DER) to the electric utility grid (or Area Electric Power System, Area EPS) involves system engineering, safety, and reliability considerations. This report documents US DOE Distribution and Interconnection R&D (formerly Distributed Power Program) activities, furthering the development and safe and reliable integration of DER interconnected with our nation's electric power systems. The key to that is system integration and technology development of the interconnection devices that perform the functions necessary to maintain the safety, power quality, and reliability of the EPS when DER are connected to it.

Method to predetermine current/power flow change in a dc grid

DEFF Research Database (Denmark)

2017-01-01

occurs at one of the AC/DC converters; establishing a generalized droop feedback gain matrix G; controlling current/power flow within DC grid towards predefined setpoints, by use of control law. The invention presents an analytical approach to derive the generalized feedback gain allowing......The invention relates to a method for controlling current/power flow within a power transmission system, comprising two or more interconnected converter stations. The method comprises the steps of: providing a DC admittance matrix given from the DC grid; providing a current distribution matrix...... for a number of, such as for all possible AC/DC converter outages; providing a DC bus voltage vector for the DC grid; the DC bus voltage vector being a vector containing the values of the voltage change at the AC/DC converters, measured at the AC/DC converters, before, during and after a forced current change...

Power Hardware-in-the-Loop Evaluation of PV Inverter Grid Support on Hawaiian Electric Feeders: Preprint

Energy Technology Data Exchange (ETDEWEB)

Nelson, Austin; Prabakar, Kumaraguru; Nagarajan, Adarsh; Nepal, Shaili; Hoke, Anderson; Asano, Marc; Ueda, Reid; Ifuku, Earle

2017-05-08

As more grid-connected photovoltaic (PV) inverters become compliant with evolving interconnections requirements, there is increased interest from utilities in understanding how to best deploy advanced grid-support functions (GSF) in the field. One efficient and cost-effective method to examine such deployment options is to leverage power hardware-in-the-loop (PHIL) testing methods. Two Hawaiian Electric feeder models were converted to real-time models in the OPAL-RT real-time digital testing platform, and integrated with models of GSF capable PV inverters that were modeled from characterization test data. The integrated model was subsequently used in PHIL testing to evaluate the effects of different fixed power factor and volt-watt control settings on voltage regulation of the selected feeders. The results of this study were provided as inputs for field deployment and technical interconnection requirements for grid-connected PV inverters on the Hawaiian Islands.

Interconnection, Integration, and Interactive Impact Analysis of Microgrids and Distribution Systems

Energy Technology Data Exchange (ETDEWEB)

Kang, Ning [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Singh, Ravindra [Argonne National Lab. (ANL), Argonne, IL (United States); Lu, Xiaonan [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-01-01

Distribution management systems (DMSs) are increasingly used by distribution system operators (DSOs) to manage the distribution grid and to monitor the status of both power imported from the transmission grid and power generated locally by a distributed energy resource (DER), to ensure that power flows and voltages along the feeders are maintained within designed limits and that appropriate measures are taken to guarantee service continuity and energy security. When microgrids are deployed and interconnected to the distribution grids, they will have an impact on the operation of the distribution grid. The challenge is to design this interconnection in such a way that it enhances the reliability and security of the distribution grid and the loads embedded in the microgrid, while providing economic benefits to all stakeholders, including the microgrid owner and operator and the distribution system operator.

The power grid AGC frequency bias coefficient online identification method based on wide area information

Science.gov (United States)

Wang, Zian; Li, Shiguang; Yu, Ting

2015-12-01

This paper propose online identification method of regional frequency deviation coefficient based on the analysis of interconnected grid AGC adjustment response mechanism of regional frequency deviation coefficient and the generator online real-time operation state by measured data through PMU, analyze the optimization method of regional frequency deviation coefficient in case of the actual operation state of the power system and achieve a more accurate and efficient automatic generation control in power system. Verify the validity of the online identification method of regional frequency deviation coefficient by establishing the long-term frequency control simulation model of two-regional interconnected power system.

Power System Study for Renewable Energy Interconnection in Malaysia

International Nuclear Information System (INIS)

Askar, O F; Ramachandaramurthy, V K

2013-01-01

The renewable energy (RE) sector has grown exponentially in Malaysia with the introduction of the Feed-In-Tariff (FIT) by the Ministry of Energy, Green Technology and Water. Photovoltaic, biogas, biomass and mini hydro are among the renewable energy sources which offer a lucrative tariff to incite developers in taking the green technology route. In order to receive the FIT, a developer is required by the utility company to perform a power system analysis which will determine the technical feasibility of an RE interconnection to the utility company's existing grid system. There are a number of aspects which the analysis looks at, the most important being the load flow and fault levels in the network after the introduction of an RE source. The analysis is done by modelling the utility company's existing network and simulating the network with the interconnection of an RE source. The results are then compared to the values before an interconnection is made as well as ensuring the voltage rise or the increase in fault levels do not violate any pre-existing regulations set by the utility company. This paper will delve into the mechanics of performing a load flow analysis and examining the results obtained.

Power System Study for Renewable Energy Interconnection in Malaysia

Science.gov (United States)

Askar, O. F.; Ramachandaramurthy, V. K.

2013-06-01

The renewable energy (RE) sector has grown exponentially in Malaysia with the introduction of the Feed-In-Tariff (FIT) by the Ministry of Energy, Green Technology and Water. Photovoltaic, biogas, biomass and mini hydro are among the renewable energy sources which offer a lucrative tariff to incite developers in taking the green technology route. In order to receive the FIT, a developer is required by the utility company to perform a power system analysis which will determine the technical feasibility of an RE interconnection to the utility company's existing grid system. There are a number of aspects which the analysis looks at, the most important being the load flow and fault levels in the network after the introduction of an RE source. The analysis is done by modelling the utility company's existing network and simulating the network with the interconnection of an RE source. The results are then compared to the values before an interconnection is made as well as ensuring the voltage rise or the increase in fault levels do not violate any pre-existing regulations set by the utility company. This paper will delve into the mechanics of performing a load flow analysis and examining the results obtained.

On the way towards smart energy supply in cities: The impact of interconnecting geographically distributed district heating grids on the energy system

DEFF Research Database (Denmark)

Dominkovic, D. F.; Bačeković, I.; Sveinbjörnsson, D.

2017-01-01

assessed. Moreover, the impact of industrial waste heat on the DH supply was also assessed. In the reference year (2013) two out of four interconnections proved to be economically viable. The results for the future energy system (2029) showed that interconnecting geographically distributed DH grids reduces...... of the future energy supply system with interconnected DH grids and installed industrial waste heat recuperation results in the lowest primary energy demand, emissions and costs. Finally, the benefits of the interconnected DH grid, in terms of system flexibility, CO2 emissions, total costs and energy efficiency...... primary energy supply by 9.5%, CO2 emissions by 11.1% and total system costs by 6.3%. Inclusion of industrial waste heat in the fully interconnected DH grid reduced primary energy supply for an additional 3%, CO2 emissions for an additional 2.2% and total system costs for an additional 1.3%. The case...

Distribution Grid Integration of Photovoltaic Systems in Germany – Implications on Grid Planning and Grid Operation

International Nuclear Information System (INIS)

Stetz, Thomas

2017-01-01

Photovoltaic is the most dispersed renewable energy source in Germany, typically interconnected to low and medium voltage systems. In recent years, cost-intensive grid reinforcements had to be undertaken all across Germany’s distribution grids in order to increase their hosting capacity for these photovoltaic installations. This paper presents an overview on research results which show that photovoltaic itself can provide ancillary services to reduce its cost of interconnection. Especially the provision of reactive power turned out to be a technically effective and economically efficient method to increase a grid’s hosting capacity for photovoltaic capacity. Different reactive power control methods were investigated, revealing significant differences with regards to their grid operation implications. Business cases for residential-scale photovoltaic applications have shifted from feed-in-tariff based active power feed-in to self-consumption. However, increasing the photovoltaic self-consumption by additional battery-storage systems is still not economically reliable in Germany. (author)

New technology for improved utilization of the interconnected power system; Ny teknologi for bedre utnyttelse av overfoerings-systemet

Energy Technology Data Exchange (ETDEWEB)

Enger, A.K.

1996-12-31

The present paper deals with methods used for improving the utilization of interconnected power systems. The author discusses new technologies for improvement and safety of power transmission. Main themes covered in this paper are HVDC (High Voltage DC) systems in Norway, possibilities of load management control, other possible/necessary measures in the grid system, and the development and trends. 21 figs.

An engineering-economic analysis of combined heat and power technologies in a (mu)grid application

Energy Technology Data Exchange (ETDEWEB)

Bailey, Owen; Ouaglal, Boubekeur; Bartholomew, Emily; Marnay, Chris; Bourassa, Norman

2002-03-01

This report describes an investigation at Ernesto Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) of the potential for coupling combined heat and power (CHP) with on-site electricity generation to provide power and heating, and cooling services to customers. This research into distributed energy resources (DER) builds on the concept of the microgrid (mGrid), a semiautonomous grouping of power-generating sources that are placed and operated by and for the benefit of its members. For this investigation, a hypothetical small shopping mall (''Microgrid Oaks'') was developed and analyzed for the cost effectiveness of installing CHP to provide the mGrid's energy needs. A mGrid consists of groups of customers pooling energy loads and installing a combination of generation resources that meets the particular mGrid's goals. This study assumes the mGrid is seeking to minimize energy costs. mGrids could operate independently of the macrogrid (the wider power network), but they are usually assumed to be connected, through power electronics, to the macrogrid. The mGrid in this study is assumed to be interconnected to the macrogrid, and can purchase some energy and ancillary services from utility providers.

A novel multi-agent decentralized win or learn fast policy hill-climbing with eligibility trace algorithm for smart generation control of interconnected complex power grids

International Nuclear Information System (INIS)

Xi, Lei; Yu, Tao; Yang, Bo; Zhang, Xiaoshun

2015-01-01

Highlights: • Proposing a decentralized smart generation control scheme for the automatic generation control coordination. • A novel multi-agent learning algorithm is developed to resolve stochastic control problems in power systems. • A variable learning rate are introduced base on the framework of stochastic games. • A simulation platform is developed to test the performance of different algorithms. - Abstract: This paper proposes a multi-agent smart generation control scheme for the automatic generation control coordination in interconnected complex power systems. A novel multi-agent decentralized win or learn fast policy hill-climbing with eligibility trace algorithm is developed, which can effectively identify the optimal average policies via a variable learning rate under various operation conditions. Based on control performance standards, the proposed approach is implemented in a flexible multi-agent stochastic dynamic game-based smart generation control simulation platform. Based on the mixed strategy and average policy, it is highly adaptive in stochastic non-Markov environments and large time-delay systems, which can fulfill automatic generation control coordination in interconnected complex power systems in the presence of increasing penetration of decentralized renewable energy. Two case studies on both a two-area load–frequency control power system and the China Southern Power Grid model have been done. Simulation results verify that multi-agent smart generation control scheme based on the proposed approach can obtain optimal average policies thus improve the closed-loop system performances, and can achieve a fast convergence rate with significant robustness compared with other methods

Power Hardware-in-the-Loop Evaluation of PV Inverter Grid Support on Hawaiian Electric Feeders

Energy Technology Data Exchange (ETDEWEB)

Nelson, Austin A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Prabakar, Kumaraguru [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nepal, Shaili [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Asano, Marc [Hawaiian Electric Company; Ueda, Reid [Hawaiian Electric Company; Ifuku, Earle [Hawaiian Electric Company

2017-10-03

As more grid-connected photovoltaic (PV) inverters become compliant with evolving interconnections requirements, there is increased interest from utilities in understanding how to best deploy advanced grid-support functions (GSF) in the field. One efficient and cost-effective method to examine such deployment options is to leverage power hardware-in-the-loop (PHIL) testing methods, which combine the fidelity of hardware tests with the flexibility of computer simulation. This paper summarizes a study wherein two Hawaiian Electric feeder models were converted to real-time models using an OPAL-RT real-time digital testing platform, and integrated with models of GSF capable PV inverters based on characterization test data. The integrated model was subsequently used in PHIL testing to evaluate the effects of different fixed power factor and volt-watt control settings on voltage regulation of the selected feeders using physical inverters. Selected results are presented in this paper, and complete results of this study were provided as inputs for field deployment and technical interconnection requirements for grid-connected PV inverters on the Hawaiian Islands.

An interconnecting bus power optimization method combining interconnect wire spacing with wire ordering

International Nuclear Information System (INIS)

Zhu Zhang-Ming; Hao Bao-Tian; En Yun-Fei; Yang Yin-Tang; Li Yue-Jin

2011-01-01

On-chip interconnect buses consume tens of percents of dynamic power in a nanometer scale integrated circuit and they will consume more power with the rapid scaling down of technology size and continuously rising clock frequency, therefore it is meaningful to lower the interconnecting bus power in design. In this paper, a simple yet accurate interconnect parasitic capacitance model is presented first and then, based on this model, a novel interconnecting bus optimization method is proposed. Wire spacing is a process for spacing wires for minimum dynamic power, while wire ordering is a process that searches for wire orders that maximally enhance it. The method, i.e., combining wire spacing with wire ordering, focuses on bus dynamic power optimization with a consideration of bus performance requirements. The optimization method is verified based on various nanometer technology parameters, showing that with 50% slack of routing space, 25.71% and 32.65% of power can be saved on average by the proposed optimization method for a global bus and an intermediate bus, respectively, under a 65-nm technology node, compared with 21.78% and 27.68% of power saved on average by uniform spacing technology. The proposed method is especially suitable for computer-aided design of nanometer scale on-chip buses. (interdisciplinary physics and related areas of science and technology)

Data processing and optimization system to study prospective interstate power interconnections

Science.gov (United States)

Podkovalnikov, Sergei; Trofimov, Ivan; Trofimov, Leonid

2018-01-01

The paper presents Data processing and optimization system for studying and making rational decisions on the formation of interstate electric power interconnections, with aim to increasing effectiveness of their functioning and expansion. The technologies for building and integrating a Data processing and optimization system including an object-oriented database and a predictive mathematical model for optimizing the expansion of electric power systems ORIRES, are described. The technology of collection and pre-processing of non-structured data collected from various sources and its loading to the object-oriented database, as well as processing and presentation of information in the GIS system are described. One of the approaches of graphical visualization of the results of optimization model is considered on the example of calculating the option for expansion of the South Korean electric power grid.

Innovative testing and measurement solutions for smart grid

CERN Document Server

Huang, Qi; Yi, Jianbo; Zhen, Wei

2015-01-01

Focuses on sensor applications and smart meters in the newly developing interconnected smart grid Focuses on sensor applications and smart meters in the newly developing interconnected smart grid Presents the most updated technological developments in the measurement and testing of power systems within the smart grid environment Reflects the modernization of electric utility power systems with the extensive use of computer, sensor, and data communications technologies, providing benefits to energy consumers and utility companies alike The leading author heads a group of researchers focusing on

IEEE Smart Grid Series of Standards IEEE 2030 (Interoperability) and IEEE 1547 (Interconnection) Status: Preprint

Energy Technology Data Exchange (ETDEWEB)

Basso, T.; DeBlasio, R.

2012-04-01

The IEEE American National Standards smart grid publications and standards development projects IEEE 2030, which addresses smart grid interoperability, and IEEE 1547TM, which addresses distributed resources interconnection with the grid, have made substantial progress since 2009. The IEEE 2030TM and 1547 standards series focus on systems-level aspects and cover many of the technical integration issues involved in a mature smart grid. The status and highlights of these two IEEE series of standards, which are sponsored by IEEE Standards Coordinating Committee 21 (SCC21), are provided in this paper.

Current Solutions: Recent Experience in Interconnecting Distributed Energy Resources

Energy Technology Data Exchange (ETDEWEB)

Johnson, M.

2003-09-01

This report catalogues selected real-world technical experiences of utilities and customers that have interconnected distributed energy assets with the electric grid. This study was initiated to assess the actual technical practices for interconnecting distributed generation and had a particular focus on the technical issues covered under the Institute of Electrical and Electronics Engineers (IEEE) 1547(TM) Standard for Interconnecting Distributed Resources With Electric Power Systems.

Importance of the fuel and power resources of Siberia for a single interconnected grid in the USSR

Energy Technology Data Exchange (ETDEWEB)

Melentev, L

1967-06-01

Attention is drawn to the difficulties involved in single national power grid in USSR. The bulk of the population and most industry is in European Russia, but that the bulk of the fuel and power resources are in Siberia, and this major difficulty is aggravated by factors of climate and distance, making fuel transport or power transmission difficult and costly. This problem, hitherto presented as the challenge which global government planning alone could win, not only still persists, but is now threatening further expansion of the Soviet economy on the basis of cheap power supplies. For the eventual overall USSR power grid, emphasis is on the importance of dc interties, correct apportionment of capacity of the various possible types of power stations and location, and the importance of mathematical statistics in planned development.

Impedance-Based Stability Analysis in Grid Interconnection Impact Study Owing to the Increased Adoption of Converter-Interfaced Generators

Directory of Open Access Journals (Sweden)

Youngho Cho

2017-09-01

Full Text Available This study investigates the emerging harmonic stability concerns to be addressed by grid planners in generation interconnection studies, owing to the increased adoption of renewable energy resources connected to the grid via power electronic converters. The wideband and high-frequency electromagnetic transient (EMT characteristics of these converter-interfaced generators (CIGs and their interaction with the grid impedance are not accurately captured in the typical dynamic studies conducted by grid planners. This paper thus identifies the desired components to be studied and subsequently develops a practical process for integrating a new CIG into a grid with the existing CIGs. The steps of this process are as follows: the impedance equation of a CIG using its control dynamics and an interface filter to the grid, for example, an LCL filter (inductor-capacitor-inductor type, is developed; an equivalent impedance model including the existing CIGs nearby and the grid observed from the point of common coupling are derived; the system stability for credible operating scenarios is assessed. Detailed EMT simulations validate the accuracy of the impedance models and stability assessment for various connection scenarios. By complementing the conventional EMT simulation studies, the proposed analytical approach enables grid planners to identify critical design parameters for seamlessly integrating a new CIG and ensuring the reliability of the grid.

Abruptness of Cascade Failures in Power Grids

Science.gov (United States)

Pahwa, Sakshi; Scoglio, Caterina; Scala, Antonio

2014-01-01

Electric power-systems are one of the most important critical infrastructures. In recent years, they have been exposed to extreme stress due to the increasing demand, the introduction of distributed renewable energy sources, and the development of extensive interconnections. We investigate the phenomenon of abrupt breakdown of an electric power-system under two scenarios: load growth (mimicking the ever-increasing customer demand) and power fluctuations (mimicking the effects of renewable sources). Our results on real, realistic and synthetic networks indicate that increasing the system size causes breakdowns to become more abrupt; in fact, mapping the system to a solvable statistical-physics model indicates the occurrence of a first order transition in the large size limit. Such an enhancement for the systemic risk failures (black-outs) with increasing network size is an effect that should be considered in the current projects aiming to integrate national power-grids into “super-grids”. PMID:24424239

Research on wind power grid-connected operation and dispatching strategies of Liaoning power grid

Science.gov (United States)

Han, Qiu; Qu, Zhi; Zhou, Zhi; He, Xiaoyang; Li, Tie; Jin, Xiaoming; Li, Jinze; Ling, Zhaowei

2018-02-01

As a kind of clean energy, wind power has gained rapid development in recent years. Liaoning Province has abundant wind resources and the total installed capacity of wind power is in the forefront. With the large-scale wind power grid-connected operation, the contradiction between wind power utilization and peak load regulation of power grid has been more prominent. To this point, starting with the power structure and power grid installation situation of Liaoning power grid, the distribution and the space-time output characteristics of wind farm, the prediction accuracy, the curtailment and the off-grid situation of wind power are analyzed. Based on the deep analysis of the seasonal characteristics of power network load, the composition and distribution of main load are presented. Aiming at the problem between the acceptance of wind power and power grid adjustment, the scheduling strategies are given, including unit maintenance scheduling, spinning reserve, energy storage equipment settings by the analysis of the operation characteristics and the response time of thermal power units and hydroelectric units, which can meet the demand of wind power acceptance and provide a solution to improve the level of power grid dispatching.

Probability of islanding in utility networks due to grid connected photovoltaic power systems

Energy Technology Data Exchange (ETDEWEB)

Verhoeven, B.

2002-09-15

This report for the International Energy Agency (IEA) made by Task 5 of the Photovoltaic Power Systems (PVPS) programme takes a look at the probability of islanding in utility networks due to grid-connected photovoltaic power systems. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. Task 5 deals with issues concerning grid-interconnection and distributed PV power systems. This report summarises the results on a study on the probability of islanding in power networks with a high penetration level of grid connected PV-systems. The results are based on measurements performed during one year in a Dutch utility network. The measurements of active and reactive power were taken every second for two years and stored in a computer for off-line analysis. The area examined and its characteristics are described, as are the test set-up and the equipment used. The ratios between load and PV-power are discussed. The general conclusion is that the probability of islanding is virtually zero for low, medium and high penetration levels of PV-systems.

Interior point algorithm-based power flow optimisation of a combined AC and DC multi-terminal grid

Directory of Open Access Journals (Sweden)

Farhan Beg

2015-01-01

Full Text Available The high cost of power electronic equipment, lower reliability and poor power handling capacity of the semiconductor devices had stalled the deployment of systems based on DC (multi-terminal direct current system (MTDC networks. The introduction of voltage source converters (VSCs for transmission has renewed the interest in the development of large interconnected grids based on both alternate current (AC and DC transmission networks. Such a grid platform also realises the added advantage of integrating the renewable energy sources into the grid. Thus a grid based on DC MTDC network is a possible solution to improve energy security and check the increasing supply demand gap. An optimal power solution for combined AC and DC grids obtained by the solution of the interior point algorithm is proposed in this study. Multi-terminal HVDC grids lie at the heart of various suggested transmission capacity increases. A significant difference is observed when MTDC grids are solved for power flows in place of conventional AC grids. This study deals with the power flow problem of a combined MTDC and an AC grid. The AC side is modelled with the full power flow equations and the VSCs are modelled using a connecting line, two generators and an AC node. The VSC and the DC losses are also considered. The optimisation focuses on several different goals. Three different scenarios are presented in an arbitrary grid network with ten AC nodes and five converter stations.

Optimal robust stabilizer design based on UPFC for interconnected power systems considering time delay

Directory of Open Access Journals (Sweden)

Koofigar Hamid Reza

2017-09-01

Full Text Available A robust auxiliary wide area damping controller is proposed for a unified power flow controller (UPFC. The mixed H2 / H∞ problem with regional pole placement, resolved by linear matrix inequality (LMI, is applied for controller design. Based on modal analysis, the optimal wide area input signals for the controller are selected. The time delay of input signals, due to electrical distance from the UPFC location is taken into account in the design procedure. The proposed controller is applied to a multi-machine interconnected power system from the IRAN power grid. It is shown that the both transient and dynamic stability are significantly improved despite different disturbances and loading conditions.

Copula-based modeling of stochastic wind power in Europe and implications for the Swiss power grid

International Nuclear Information System (INIS)

Hagspiel, Simeon; Papaemannouil, Antonis; Schmid, Matthias; Andersson, Göran

2012-01-01

Highlights: ► We model stochastic wind power using copula theory. ► Stochastic wind power is integrated in a European system adequacy evaluation. ► The Swiss power grid is put at risk by further integrating wind power in Europe. ► System elements located at or close to Swiss borders are affected the most. ► A criticality indicator allows prioritizing expansion plans on a probabilistic basis. -- Abstract: Large scale integration of wind energy poses new challenges to the European power system due to its stochastic nature and often remote location. In this paper a multivariate uncertainty analysis problem is formulated for the integration of stochastic wind energy in the European grid. By applying copula theory a synthetic set of data is generated from scarce wind speed reanalysis data in order to achieve the increased sample size for the subsequent Monte Carlo simulation. In the presented case study, European wind power samples are generated from the modeled stochastic process. Under the precondition of a modeled perfect market environment, wind power impacts dispatch decisions and therefore leads to alterations in power balances. Stochastic power balances are implemented in a detailed model of the European electricity network, based on the generated samples. Finally, a Monte Carlo method is used to determine power flows and contingencies in the system. An indicator is elaborated in order to analyze risk of overloading and to prioritize necessary grid reinforcements. Implications for the Swiss power grid are investigated in detail, revealing that the current system is significantly put at risk in certain areas by the further integration of wind power in Europe. It is the first time that the results of a probabilistic model for wind energy are further deployed within a power system analysis of the interconnected European grid. The method presented in this paper allows to account for stochastic wind energy in a load flow analysis and to evaluate

Report on technological survey in fiscal 1999. Demonstration test for smoothing grid interconnection (Demonstration test using simulation); 1999 nendo keito renkei enkatsuka jissho shiken chosa hokokusho. Simulation ni yoru jissho shiken

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Examinations have been made by using simulation on a device having single operation detecting function, that is the single operation detector. The discussions are given on (1) an induction generator and a reactive power compensation type detector system interconnected to a high-voltage grid, and (2) a three-phase inverter, a reactive power variation type detector, and a QC mode frequency shifting detector system. In Item (1), it was learned that, because of variation induction force being small in the case of operation having become single operation, the variation signal must be made greater, and in Item (2), the discussions have not gone as far as a conclusion can be drawn. In addition, assuming a synchronous motor interconnected to a high voltage grid, discussions were given on the effects of disturbance to the interconnected system on the functions of the single operation detector, whereas it was verified that there are no problems in practical use. Furthermore, discussions were given on the self excitation phenomenon in an induction generator, and requirements for omitting the ground fault overvoltage relay in a discrete type power supply. (NEDO)

On the Distribution of Lightning Current among Interconnected Grounding Systems in Medium Voltage Grids

Directory of Open Access Journals (Sweden)

Guido Ala

2018-03-01

Full Text Available This paper presents the results of a first investigation on the effects of lightning stroke on medium voltage installations’ grounding systems, interconnected with the metal shields of the Medium Voltage (MV distribution grid cables or with bare buried copper ropes. The study enables us to evaluate the distribution of the lightning current among interconnected ground electrodes in order to estimate if the interconnection, usually created to reduce ground potential rise during a single-line-to-ground fault, can give place to dangerous situations far from the installation hit by the lightning stroke. Four different case studies of direct lightning stroke are presented and discussed: (1 two secondary substations interconnected by the cables’ shields; (2 two secondary substations interconnected by a bare buried conductor; (3 a high voltage/medium voltage station connected with a secondary substation by the medium voltage cables’ shields; (4 a high voltage/medium voltage station connected with a secondary substation by a bare buried conductor. The results of the simulations show that a higher peak-lowering action on the lighting-stroke current occurs due to the use of bare conductors as interconnection elements in comparison to the cables’ shields.

Grid-Tied Photovoltaic Power System

Science.gov (United States)

Eichenberg, Dennis J.

2011-01-01

A grid-tied photovoltaic (PV) power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. Operating costs of a PV power system are low compared to conventional power technologies. This method can displace the highest-cost electricity during times of peak demand in most climatic regions, and thus reduce grid loading. Net metering is often used, in which independent power producers such as PV power systems are connected to the utility grid via the customers main service panels and meters. When the PV power system is generating more power than required at that location, the excess power is provided to the utility grid. The customer pays the net of the power purchased when the on-site power demand is greater than the onsite power production, and the excess power is returned to the utility grid. Power generated by the PV system reduces utility demand, and the surplus power aids the community. Modern PV panels are readily available, reliable, efficient, and economical, with a life expectancy of at least 25 years. Modern electronics have been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy equal to the modern PV panels. The grid-tied PV power system was successfully designed and developed, and this served to validate the basic principles developed, and the theoretical work that was performed. Grid-tied PV power systems are reliable, maintenance- free, long-life power systems, and are of significant value to NASA and the community. Of particular value are the analytical tools and capabilities that have been successfully developed. Performance predictions can be made confidently for grid-tied PV systems of various scales. The work was done under the NASA Hybrid Power Management (HPM

The effect of long-distance interconnection on wind power variability

International Nuclear Information System (INIS)

Fertig, Emily; Apt, Jay; Jaramillo, Paulina; Katzenstein, Warren

2012-01-01

We use time- and frequency-domain techniques to quantify the extent to which long-distance interconnection of wind plants in the United States would reduce the variability of wind power output. Previous work has shown that interconnection of just a few wind plants across moderate distances could greatly reduce the ratio of fast- to slow-ramping generators in the balancing portfolio. We find that interconnection of aggregate regional wind plants would not reduce this ratio further but would reduce variability at all frequencies examined. Further, interconnection of just a few wind plants reduces the average hourly change in power output, but interconnection across regions provides little further reduction. Interconnection also reduces the magnitude of low-probability step changes and doubles firm power output (capacity available at least 92% of the time) compared with a single region. First-order analysis indicates that balancing wind and providing firm power with local natural gas turbines would be more cost-effective than with transmission interconnection. For net load, increased wind capacity would require more balancing resources but in the same proportions by frequency as currently, justifying the practice of treating wind as negative load. (letter)

Decision Optimization for Power Grid Operating Conditions with High- and Low-Voltage Parallel Loops

Directory of Open Access Journals (Sweden)

Dong Yang

2017-05-01

Full Text Available With the development of higher-voltage power grids, the high- and low-voltage parallel loops are emerging, which lead to energy losses and even threaten the security and stability of power systems. The multi-infeed high-voltage direct current (HVDC configurations widely appearing in AC/DC interconnected power systems make this situation even worse. Aimed at energy saving and system security, a decision optimization method for power grid operating conditions with high- and low-voltage parallel loops is proposed in this paper. Firstly, considering hub substation distribution and power grid structure, parallel loop opening schemes are generated with GN (Girvan-Newman algorithms. Then, candidate opening schemes are preliminarily selected from all these generated schemes based on a filtering index. Finally, with the influence on power system security, stability and operation economy in consideration, an evaluation model for candidate opening schemes is founded based on analytic hierarchy process (AHP. And a fuzzy evaluation algorithm is used to find the optimal scheme. Simulation results of a New England 39-bus system and an actual power system validate the effectiveness and superiority of this proposed method.

Smart Grids and Distributed Generation

Directory of Open Access Journals (Sweden)

Dorin BICĂ

2018-06-01

Full Text Available This paper describes the main characteristics of Smart Grids and distributed generation. Smart Grids can be defined as a modernization of the power system so it monitors, protects and automatically optimizes the operation of its interconnected elements (power plants, transmission and distribution system, industrial and residential loads. Distributed generation (DG refers to the production of electricity near the consumption place using renewable energy sources. A load flow analysis is performed for the IEEE14 system in which a DG source (a 5MW wind turbine is added that is on-grid or off-grid. The power losses are determined for these two cases.

76 FR 39870 - PJM Interconnection, LLC; PJM Power Providers Group v. PJM Interconnection, LLC; Notice of Date...

Science.gov (United States)

2011-07-07

.... EL11-20-001] PJM Interconnection, LLC; PJM Power Providers Group v. PJM Interconnection, LLC; Notice of... Sell Offers for Planned Generation Capacity Resources submitted into PJM's Reliability Pricing Model... presents an opportunity to exercise buyer market power; (2) whether the Fixed Resource Requirement (FRR...

Coordinated Control of Multiterminal DC Grid Power Injections for Improved Rotor-Angle Stability Based on Lyapunov Theory

DEFF Research Database (Denmark)

Eriksson, Robert

2014-01-01

The stability of an interconnected ac/dc system is affected by disturbances occurring in the system. Disturbances, such as three-phase faults, may jeopardize the rotor-angle stability and, thus, the generators fall out of synchronism. The possibility of fast change of the injected powers...... by the multiterminal dc grid can, by proper control action, enhance this stability. This paper proposes a new time optimal control strategy for the injected power of multiterminal dc grids to enhance the rotor-angle stability. The controller is time optimal, since it reduces the impact of a disturbance as fast...

Offshore grid transmission planning using approximated HVDC power flows

Energy Technology Data Exchange (ETDEWEB)

Torbaghan, Shahab Shariat; Rawn, Barry G.; Gibescu, Madeleine; Meijden, Mart van der [Delft Univ. of Technology (Netherlands). Dept. of Electrical Sustainable Energy

2012-07-01

In this paper we introduce an optimization framework which determines a socially optimum design of a HVDC offshore grid, under the assumption of a centralized network expansion planning scheme. This gives the optimum grid topology and interconnections capacity. In addition, the analytical solution to the optimization problem yields a market structure that expresses the relationship between the different regions' electricity prices and congestion charges associated with the interconnections. The optimization model sets the transmission capacities in a way that congestion shadow prices to be collected by the end of the economic lifetime of the project pay off the initial investment capital. We use this framework to study the impact of exercising different dispatching policies on the optimum design of the grid. The framework is applied to a multi-bus test system that functions under 8 different time periods. (orig.)

Grid Integration | Water Power | NREL

Science.gov (United States)

Grid Integration Grid Integration For marine and hydrokinetic technologies to play a larger role in supplying the nation's energy needs, integration into the U.S. power grid is an important challenge to address. Efficient integration of variable power resources like water power is a critical part of the

Virtual interconnection platform initiative scoping study

Energy Technology Data Exchange (ETDEWEB)

Liu, Yong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kou, Gefei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pan, Zuohong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Yilu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); King Jr., Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-01-01

Due to security and liability concerns, the research community has limited access to realistic large-scale power grid models to test and validate new operation and control methodologies. It is also difficult for industry to evaluate the relative value of competing new tools without a common platform for comparison. This report proposes to develop a large-scale virtual power grid model that retains basic features and represents future trends of major U.S. electric interconnections. This model will include realistic power flow and dynamics information as well as a relevant geospatial distribution of assets. This model will be made widely available to the research community for various power system stability and control studies and can be used as a common platform for comparing the efficacies of various new technologies.

Power grid reliability and security

Energy Technology Data Exchange (ETDEWEB)

Bose, Anjan [Washington State Univ., Pullman, WA (United States); Venkatasubramanian, Vaithianathan [Washington State Univ., Pullman, WA (United States); Hauser, Carl [Washington State Univ., Pullman, WA (United States); Bakken, David [Washington State Univ., Pullman, WA (United States); Anderson, David [Washington State Univ., Pullman, WA (United States); Zhao, Chuanlin [Washington State Univ., Pullman, WA (United States); Liu, Dong [Washington State Univ., Pullman, WA (United States); Yang, Tao [Washington State Univ., Pullman, WA (United States); Meng, Ming [Washington State Univ., Pullman, WA (United States); Zhang, Lin [Washington State Univ., Pullman, WA (United States); Ning, Jiawei [Washington State Univ., Pullman, WA (United States); Tashman, Zaid [Washington State Univ., Pullman, WA (United States)

2015-01-31

This project has led to the development of a real-time simulation platform for electric power grids called Grid Simulator or GridSim for simulating the dynamic and information network interactions of large- scale power systems. The platform consists of physical models of power system components including synchronous generators, loads and control, which are simulated using a modified commercial power simulator namely Transient Stability Analysis Tool (TSAT) [1] together with data cleanup components, as well as an emulated substation level and wide-area power analysis components. The platform also includes realistic representations of communication network middleware that can emulate the real-time information flow back and forth between substations and control centers in wide-area power systems. The platform has been validated on a realistic 6000-bus model of the western American power system. The simulator GridSim developed in this project is the first of its kind in its ability to simulate real-time response of large-scale power grids, and serves as a cost effective real-time stability and control simulation platform for power industry.

Power grids

International Nuclear Information System (INIS)

Viterbo, J.

2012-01-01

The implementation of renewable energies represents new challenges for electrical systems. The objective: making power grids smarter so they can handle intermittent production. The advent of smart grids will allow flexible operations like distributing energy in a multidirectional manner instead of just one way and it will make electrical systems capable of integrating actions by different users, consumers and producers in order to maintain efficient, sustainable, economical and secure power supplies. Practically speaking, they associate sensors, instrumentation and controls with information processing and communication systems in order to create massively automated networks. Smart grids require huge investments: for example more than 7 billion dollars have been invested in China and in the Usa in 2010 and France is ranked 9. worldwide with 265 million dollars invested. It is expected that smart grids will promote the development of new business models and a change in the value chain for energy. Decentralized production combined with the probable introduction of more or less flexible rates for sales or purchases and of new supplier-customer relationships will open the way to the creation of new businesses. (A.C.)

Ontario's intertie capacity and electricity trade in the interconnected system

International Nuclear Information System (INIS)

Dorey, S.

2002-01-01

Hydro One's capacity of existing interconnections were described. The Ontario utility is within reach of about 320 GW electricity markets in neighbouring Quebec, New York, Michigan, Minnesota, and Manitoba. It is also within reach of 50 million customers, and 30 per cent of total U.S. energy consumption. The author emphasized the need for expanded interties and new interconnections. The status of new interconnections was described along with the rules regarding electric power import, export and wheeling. It was noted that compared to the United States, Canada has a higher proportion of clean hydro and nuclear power plants in its mix of power generation. Markets across North America are adopting electricity restructuring and open competition. However, the transmission grids were not designed to support market-driven electricity trading. Most transmission grids were built when utilities were tightly regulated and provided service only within their assigned regions. The current energy infrastructure is not equipped for large-scale swapping of power in competitive markets. It was also noted that growth in US power flows is outpacing transmission investment. This paper addressed the issue of license requirements, transmitter proposals for regulated investments, and non-rate base transmitter investments. It was concluded that while market rules are flexible enough to encourage inter-jurisdictional trade, the rules have to facilitate and encourage transmission investment. 8 figs

Controllable Photovoltaic Grid Power Injection with an Assistance of Energy Storage System

DEFF Research Database (Denmark)

Morvaj, Boran; Dragicevic, Tomislav; Krajcar, Slavko

2013-01-01

This paper focuses on modeling and simulation of controllable Photovoltaic Battery Power System (PV BPS) interconnected to the electrical utility. After elaboration of modeling principles for different components appearing in the system, simulations of two types of PV plants connected to one branch...... of distribution network have been carried out. First one is connected through a three-phase inverter with battery string connected to a DC-link and the second string is connected to the grid in single phase configuration. In this proposed configuration unpredictable variations of irradiation and temperature...

Enhancing the Capacity of the AC Distribution System Using DC Interlinks - A Step Towards Future DC Grid

DEFF Research Database (Denmark)

Chaudhary, Sanjay; Guerrero, Josep M.; Teodorescu, Remus

2015-01-01

The development of distributed generation system and electric vehicles is bound to strain the distribution network. A typical radial distribution feeder suffers from the voltage fluctuation and feeder overload in the presence of a large amount of variable renewable generation. This paper presents...... a concept of enhancing the power handling capacity of distribution networks using dc grid interconnections. Control of both the active and reactive power exchange between the ac feeder and the interconnecting power converter has been proposed for the voltage regulation at the ac feeder terminal. Besides......, the dc grid interconnection also allows the introduction of a common storage system which can be shared by the connected ac feeders, and the dc grid connection to other renewable energy resources. The increased power handling capacity and improved voltage profile of the ac distribution feeder using...

Decentralized automatic generation control of interconnected power systems incorporating asynchronous tie-lines.

Science.gov (United States)

Ibraheem; Hasan, Naimul; Hussein, Arkan Ahmed

2014-01-01

This Paper presents the design of decentralized automatic generation controller for an interconnected power system using PID, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The designed controllers are tested on identical two-area interconnected power systems consisting of thermal power plants. The area interconnections between two areas are considered as (i) AC tie-line only (ii) Asynchronous tie-line. The dynamic response analysis is carried out for 1% load perturbation. The performance of the intelligent controllers based on GA and PSO has been compared with the conventional PID controller. The investigations of the system dynamic responses reveal that PSO has the better dynamic response result as compared with PID and GA controller for both type of area interconnection.

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

International Nuclear Information System (INIS)

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.

Smart grid communication-enabled intelligence for the electric power grid

CERN Document Server

Bush, Stephen F

2014-01-01

This book bridges the divide between the fields of power systems engineering and computer communication through the new field of power system information theory. Written by an expert with vast experience in the field, this book explores the smart grid from generation to consumption, both as it is planned today and how it will evolve tomorrow. The book focuses upon what differentiates the smart grid from the ""traditional"" power grid as it has been known for the last century. Furthermore, the author provides the reader with a fundamental understanding of both power systems and communication ne

Multilateral cooperation for power interconnection in Northeast Asia

Directory of Open Access Journals (Sweden)

Chudinova Lyudmila

2018-01-01

Full Text Available Considered is experience of electric power integration in different parts of the world with emphasis on bilateral/multilateral interstate structures intended for promotion and development of interstate power grids. Analysed are Northeast Asian intergovernmental structures providing bilateral energy and power cooperation between Russia and other countries of the region. Multilateral cooperation in the field is just emerging, but should play a key role in promotion and development of Northeast Asian power grid.

Interconnected Power Systems Mexico-Guatemala financed by BID

International Nuclear Information System (INIS)

Martinez, Veronica

2003-01-01

The article describes the plans for the interconnection of the electric power systems of Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama and Mexico within the project Plan Pueba Panama. The objective of the interconnection is to create an electric market in the region that contributes to reduce costs and prices. The project will receive a financing of $37.5 millions of US dollars from the Banco Intrameramericano de Desarrollo (BID)

Models for the modern power grid

Science.gov (United States)

Nardelli, Pedro H. J.; Rubido, Nicolas; Wang, Chengwei; Baptista, Murilo S.; Pomalaza-Raez, Carlos; Cardieri, Paulo; Latva-aho, Matti

2014-10-01

This article reviews different kinds of models for the electric power grid that can be used to understand the modern power system, the smart grid. From the physical network to abstract energy markets, we identify in the literature different aspects that co-determine the spatio-temporal multilayer dynamics of power system. We start our review by showing how the generation, transmission and distribution characteristics of the traditional power grids are already subject to complex behaviour appearing as a result of the the interplay between dynamics of the nodes and topology, namely synchronisation and cascade effects. When dealing with smart grids, the system complexity increases even more: on top of the physical network of power lines and controllable sources of electricity, the modernisation brings information networks, renewable intermittent generation, market liberalisation, prosumers, among other aspects. In this case, we forecast a dynamical co-evolution of the smart grid and other kind of networked systems that cannot be understood isolated. This review compiles recent results that model electric power grids as complex systems, going beyond pure technological aspects. From this perspective, we then indicate possible ways to incorporate the diverse co-evolving systems into the smart grid model using, for example, network theory and multi-agent simulation.

Power Grid:Connecting the world

Institute of Scientific and Technical Information of China (English)

Liu Liang; Zhu Li

2012-01-01

With the acceleration of global economic integration,the trend has been towards opening up markets.Large enterprises in countries around the world,the developed countries in particular,attach great importance to going abroad,with the aim to optimally allocate energy resources in a wider range.Actively responding to the "going out" strategy of the State,the two giant power grid enterprises in China,State Grid Corporation of China (SGCC) and China Southern Power Grid (CSG),have made plans for grid development in line with the State's energy strategy and global resources allocation.

Grid-code of Croatian power system

International Nuclear Information System (INIS)

Toljan, I.; Mesic, M.; Kalea, M.; Koscak, Z.

2003-01-01

Grid Rules by the Croatian Electricity Utility deal with the control and usage of the Croatian power system's transmission and distribution grid. Furthermore, these rules include obligations and permissions of power grid users and owners, with the aim of a reliable electricity supply.(author)

Reliability of Ceramic Column Grid Array Interconnect Packages Under Extreme Temperatures

Science.gov (United States)

Ramesham, Rajeshuni

2011-01-01

A paper describes advanced ceramic column grid array (CCGA) packaging interconnects technology test objects that were subjected to extreme temperature thermal cycles. CCGA interconnect electronic package printed wiring boards (PWBs) of polyimide were assembled, inspected nondestructively, and, subsequently, subjected to ex - treme-temperature thermal cycling to assess reliability for future deep-space, short- and long-term, extreme-temperature missions. The test hardware consisted of two CCGA717 packages with each package divided into four daisy-chained sections, for a total of eight daisy chains to be monitored. The package is 33 33 mm with a 27 27 array of 80%/20% Pb/Sn columns on a 1.27-mm pitch. The change in resistance of the daisy-chained CCGA interconnects was measured as a function of the increasing number of thermal cycles. Several catastrophic failures were observed after 137 extreme-temperature thermal cycles, as per electrical resistance measurements, and then the tests were continued through 1,058 thermal cycles to corroborate and understand the test results. X-ray and optical inspection have been made after thermal cycling. Optical inspections were also conducted on the CCGA vs. thermal cycles. The optical inspections were conclusive; the x-ray images were not. Process qualification and assembly is required to optimize the CCGA assembly, which is very clear from the x-rays. Six daisy chains were open out of seven daisy chains, as per experimental test data reported. The daisy chains are open during the cold cycle, and then recover during the hot cycle, though some of them also opened during the hot thermal cycle..

Controllable Grid Interface for Testing Ancillary Service Controls and Fault Performance of Utility-Scale Wind Power Generation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Gevorgian, Vahan; Koralewicz, Przemyslaw; Wallen, Robb; Muljadi, Eduard

2017-02-01

The rapid expansion of wind power has led many transmission system operators to demand modern wind power plants to comply with strict interconnection requirements. Such requirements involve various aspects of wind power plant operation, including fault ride-through and power quality performance as well as the provision of ancillary services to enhance grid reliability. During recent years, the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy has developed a new, groundbreaking testing apparatus and methodology to test and demonstrate many existing and future advanced controls for wind generation (and other renewable generation technologies) on the multimegawatt scale and medium-voltage levels. This paper describes the capabilities and control features of NREL's 7-MVA power electronic grid simulator (also called a controllable grid interface, or CGI) that enables testing many active and reactive power control features of modern wind turbine generators -- including inertial response, primary and secondary frequency responses, and voltage regulation -- under a controlled, medium-voltage grid environment. In particular, this paper focuses on the specifics of testing the balanced and unbalanced fault ride-through characteristics of wind turbine generators under simulated strong and weak medium-voltage grid conditions. In addition, this paper provides insights on the power hardware-in-the-loop feature implemented in the CGI to emulate (in real time) the conditions that might exist in various types of electric power systems under normal operations and/or contingency scenarios. Using actual test examples and simulation results, this paper describes the value of CGI as an ultimate modeling validation tool for all types of 'grid-friendly' controls by wind generation.

Superconductors in the power grid materials and applications

CERN Document Server

2015-01-01

Superconductors offer high throughput with low electric losses and have the potential to transform the electric power grid. Transmission networks incorporating cables of this type could, for example, deliver more power and enable substantial energy savings. Superconductors in the Power Grid: Materials and Applications provides an overview of superconductors and their applications in power grids. Sections address the design and engineering of cable systems and fault current limiters and other emerging applications for superconductors in the power grid, as well as case studies of industrial applications of superconductors in the power grid. Expert editor from highly respected US government-funded research centre Unique focus on superconductors in the power grid Comprehensive coverage

Encoded low swing for ultra low power interconnect

NARCIS (Netherlands)

Krishnan, R.; Pineda de Gyvez, J.

2003-01-01

We present a novel encoded-low swing technique for ultra low power interconnect. Using this technique and an efficient circuit implementation, we achieve an average of 45.7% improvement in the power-delay product over the schemes utilizing low swing techniques alone, for random bit streams. Also, we

Design and Analysis of Grid Connected Photovoltaic Fed Unified Power Quality Conditioner

Science.gov (United States)

Dash, Santanu Kumar; Ray, Pravat Kumar

2016-06-01

This paper proposes the integration scheme and operation of the Unified Power Quality conditioner (UPQC) with Photovoltaic source as distributed generations for power quality improvement. Thus, it provides a novel PV-grid integration configuration and prevents any adverse situation related to current or voltage in power system. Voltage related issues are maintained by the series part of UPQC and the current related issues are handles by shunt part of the UPQC. The various operation modes of PV-UPQC schemes are broadly classified according to the direction of power flow, (i) Interconnected mode, (ii) Islanding mode. PV-UPQC has advantage over the conventional UPQC scheme as it has developed the capability to compensate the voltage interruption problems Control algorithms for shunt and series part of the UPQC is implemented. Development of the proposed configuration has been designed in the laboratory with control algorithm implemented in dSPACE and results are discussed.

76 FR 45248 - PJM Interconnection, L.L.C., PJM Power Providers Group v. PJM Interconnection, L.L.C...

Science.gov (United States)

2011-07-28

...-002; Docket No. EL11-20-001] PJM Interconnection, L.L.C., PJM Power Providers Group v. PJM Interconnection, L.L.C.; Supplemental Notice of Staff Technical Conference On June 13, 2011, the Commission issued... Resources Services, Inc., Maryland Public Service Commission, Monitoring Analytics, L.L.C., National Rural...

Application Note: Power Grid Modeling With Xyce.

Energy Technology Data Exchange (ETDEWEB)

Sholander, Peter E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-06-01

This application note describes how to model steady-state power flows and transient events in electric power grids with the SPICE-compatible Xyce TM Parallel Electronic Simulator developed at Sandia National Labs. This application notes provides a brief tutorial on the basic devices (branches, bus shunts, transformers and generators) found in power grids. The focus is on the features supported and assumptions made by the Xyce models for power grid elements. It then provides a detailed explanation, including working Xyce netlists, for simulating some simple power grid examples such as the IEEE 14-bus test case.

Active and Reactive Power Control Strategy for Grid-Connected Six-Phase Generator by Using Multi-Modular Matrix Converters

Directory of Open Access Journals (Sweden)

David Caballero

2016-12-01

Full Text Available This paper proposes an active and reactive power control strategy based on predictive control approaches applied to gridconnected renewable energy systems. To accomplish this a multi-modular matrix converter topologies are used in combination with a simple but efficient grid synchronization strategy. The theoretical performance analysis is performed considering a six-phase wind energy generator system interconnected with the grid. Results based on a MATLAB/Simulink simulation environment are discussed and the most relevant characteristics of the proposed control technique are highlighted considering the total harmonic distortion and the mean squared error as a parameters of performance.

Occurrence and countermeasures of urban power grid accident

Science.gov (United States)

Wei, Wang; Tao, Zhang

2018-03-01

With the advance of technology, the development of network communication and the extensive use of power grids, people can get to know power grid accidents around the world through the network timely. Power grid accidents occur frequently. Large-scale power system blackout and casualty accidents caused by electric shock are also fairly commonplace. All of those accidents have seriously endangered the property and personal safety of the country and people, and the development of society and economy is severely affected by power grid accidents. Through the researches on several typical cases of power grid accidents at home and abroad in recent years and taking these accident cases as the research object, this paper will analyze the three major factors that cause power grid accidents at present. At the same time, combining with various factors and impacts caused by power grid accidents, the paper will put forward corresponding solutions and suggestions to prevent the occurrence of the accident and lower the impact of the accident.

On- and off-grid operation of hybrid renewable power plants: When are the economics favorable?

Science.gov (United States)

Petrakopoulou, F.; Santana, D.

2016-12-01

Hybrid renewable energy conversion systems offer a good alternative to conventional systems in locations where the extension of the electrical grid is difficult or not economical or where the cost of electricity is high. However, stand-alone operation implies net energy output restrictions (limited to exclusively serve the energy demand of a region), capacity oversizing and large storage facilities. In interconnected areas, on the other hand, the operational restrictions of the power stations change significantly and the efficiencies and costs of renewable technologies become more favorable. In this paper, the operation of three main renewable technologies (CSP, PV and wind) is studied assuming both hybrid and individual operation for both autonomous and inter-connected operation. The case study used is a Mediterranean island of ca. 3,000 inhabitants. Each system is optimized to fully cover the energy demand of the community. In addition, in the on-grid operation cases, it is required that the annual energy generated from the renewable sources is net positive (i.e., the island generates at least as much energy as it uses). It is found that when connected to the grid, hybridization of more than one technology is not required to satisfy the energy demand, as expected. Each of the renewable technologies investigated can satisfy the annual energy demand individually, without significant complications. In addition, the cost of electricity generated with the three studied technologies drops significantly for on-grid applications, when compared to off-grid operation. However, when compared to business-as-usual scenarios in both the on- and off-grid cases, both investigated hybrid and single-technology renewable scenarios are found to be economically viable. A sensitivity analysis reveals the limits of the acceptable costs that make the technologies favorable when compared to conventional alternatives.

Grid Converters for Photovoltaic and Wind Power Systems

DEFF Research Database (Denmark)

Teodorescu, Remus; Liserre, Marco; Rodriguez, Pedro

power, operation within a wide range of voltage and frequency, voltage ride-through capability, reactive current injection during faults, grid services support. This book explains the topologies, modulation and control of grid converters for both photovoltaic and wind power applications. In addition...... to power electronics, this book focuses on the specific applications in photovoltaic wind power systems where grid condition is an essential factor. With a review of the most recent grid requirements for photovoltaic and wind power systems, the book discusses these other relevant issues: Modern grid...... inverter topologies for photovoltaic and wind turbines Islanding detection methods for photovoltaic systems Synchronization techniques based on second order generalized integrators (SOGI) Advanced synchronization techniques with robust operation under grid unbalance condition grid filter design and active...

Hysteresis current control technique of VSI for compensation of grid-connected unbalanced loads

DEFF Research Database (Denmark)

Pouresmaeil, Edris; Akorede, Mudathir Funsho; Montesinos-Miracle, Daniel

2014-01-01

interconnection issues that usually arise as DG units connect to the electric grid. The proposed strategy, implemented in Matlab/Simulink environment in different operating scenarios, provides compensation for active, reactive, unbalanced, and harmonic current components of grid-connected nonlinear unbalanced...... resources as they connect to the exiting power grid could provoke many power quality problems on the grid side. For this reason, due considerations must be given to power generation and safe running before DG units is actually integrated into the power grid. The main aim of this paper is to address the grid...... loads. The simulation results obtained in this study demonstrate the level of accuracy of the proposed technique, which ensure a balance in the overall grid phase currents, injection of maximum available power from DG resources to the grid, improvement of the utility grid power factor, and a reduction...

Electric network interconnection of Mashreq Arab Countries

International Nuclear Information System (INIS)

El-Amin, I.M.; Al-Shehri, A.M.; Opoku, G.; Al-Baiyat, S.A.; Zedan, F.M.

1994-01-01

Power system interconnection is a well established practice for a variety of technical and economical reasons. Several interconnected networks exist worldwide for a number of factors. Some of these networks cross international boundaries. This presentation discusses the future developments of the power systems of Mashreq Arab Countries (MAC). MAC consists of Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, United Arab Emirates (UAE), and Yemen. Mac power systems are operated by government or semigovernment bodies. Many of these countries have national or regional electric grids but are generally isolated from each other. With the exception of Saudi Arabia power systems, which employ 60 Hz, all other MAC utilities use 50 Hz frequency. Each country is served by one utility, except Saudi Arabia, which is served by four major utilities and some smaller utilities serving remote towns and small load centers. The major utilities are the Saudi Consolidated electric Company in the Eastern Province (SCECO East), SCECO Center, SCECO West, and SCECO South. These are the ones considered in this study. The energy resources in MAC are varied. Countries such as Egypt, Iraq, and Syria have significant hydro resources.The gulf countries and Iraq have abundant fossil fuel, The variation in energy resources as well as the characteristics of the electric load make it essential to look into interconnections beyond the national boundaries. Most of the existing or planned interconnections involve few power systems. A study involving 12 countries and over 20 utilities with different characteristics represents a very large scale undertaking

Strategic siting and regional grid interconnections key to low-carbon futures in African countries

Energy Technology Data Exchange (ETDEWEB)

Wu, Grace C. [Univ. of California, Berkeley, CA (United States). Energy and Resources Group; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). International Energy Studies Group; Deshmukh, Ranjit [Univ. of California, Berkeley, CA (United States). Energy and Resources Group; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). International Energy Studies Group; Ndhlukula, Kudakwashe [Namibia Univ. of Science and Technology, Windhoek, (Namibia). Southern Africa Development Community (SADC) Centre for Renewable Energy and Energy Efficiency; Radojicic, Tijana [International Renewable Energy Agency, Masdar City, Abu Dhabi (United Arab Emirates); Reilly-Moman, Jessica [Univ. of California, Berkeley, CA (United States). Energy and Resources Group; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). International Energy Studies Group; Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). International Energy Studies Group; Kammen, Daniel M. [Univ. of California, Berkeley, CA (United States). Energy and Resources Group; Callaway, Duncan S. [Univ. of California, Berkeley, CA (United States). Energy and Resources Group

2017-03-27

Recent forecasts suggest that African countries must triple their current electricity generation by 2030. Our multicriteria assessment of wind and solar potential for large regions of Africa shows how economically competitive and low-environmental– impact renewable resources can significantly contribute to meeting this demand. We created the Multicriteria Analysis for Planning Renewable Energy (MapRE) framework to map and characterize solar and wind energy zones in 21 countries in the Southern African Power Pool (SAPP) and the Eastern Africa Power Pool (EAPP) and find that potential is several times greater than demand in many countries. Significant fractions of demand can be quickly served with “no-regrets” options—or zones that are low-cost, low-environmental impact, and highly accessible. Because no-regrets options are spatially heterogeneous, international interconnections are necessary to help achieve low-carbon development for the region as a whole, and interconnections that support the best renewable options may differ from those planned for hydropower expansion. Additionally, interconnections and selecting wind sites to match demand reduce the need for SAPP-wide conventional generation capacity by 9.5% in a high-wind scenario, resulting in a 6–20% cost savings, depending on the avoided conventional technology. Strategic selection of low-impact and accessible zones is more cost effective with interconnections compared with solutions without interconnections. In conclusion, the overall results are robust to multiple load growth scenarios. Together, results show that multicriteria site selection and deliberate planning of interconnections may significantly increase the economic and environmental competitiveness of renewable alternatives relative to conventional generation.

Strategic siting and regional grid interconnections key to low-carbon futures in African countries.

Science.gov (United States)

Wu, Grace C; Deshmukh, Ranjit; Ndhlukula, Kudakwashe; Radojicic, Tijana; Reilly-Moman, Jessica; Phadke, Amol; Kammen, Daniel M; Callaway, Duncan S

2017-04-11

Recent forecasts suggest that African countries must triple their current electricity generation by 2030. Our multicriteria assessment of wind and solar potential for large regions of Africa shows how economically competitive and low-environmental-impact renewable resources can significantly contribute to meeting this demand. We created the Multicriteria Analysis for Planning Renewable Energy (MapRE) framework to map and characterize solar and wind energy zones in 21 countries in the Southern African Power Pool (SAPP) and the Eastern Africa Power Pool (EAPP) and find that potential is several times greater than demand in many countries. Significant fractions of demand can be quickly served with "no-regrets" options-or zones that are low-cost, low-environmental impact, and highly accessible. Because no-regrets options are spatially heterogeneous, international interconnections are necessary to help achieve low-carbon development for the region as a whole, and interconnections that support the best renewable options may differ from those planned for hydropower expansion. Additionally, interconnections and selecting wind sites to match demand reduce the need for SAPP-wide conventional generation capacity by 9.5% in a high-wind scenario, resulting in a 6-20% cost savings, depending on the avoided conventional technology. Strategic selection of low-impact and accessible zones is more cost effective with interconnections compared with solutions without interconnections. Overall results are robust to multiple load growth scenarios. Together, results show that multicriteria site selection and deliberate planning of interconnections may significantly increase the economic and environmental competitiveness of renewable alternatives relative to conventional generation.

Validation of IEEE P1547.1 Interconnection Test Procedures: ASCO 7000 Soft Load Transfer System

Energy Technology Data Exchange (ETDEWEB)

Kroposki, B.; Englebretson, S.; Pink, C.; Daley, J.; Siciliano, R.; Hinton, D.

2003-09-01

This report presents the preliminary results of testing the ASCO 7000 Soft Load Transfer System according to IEEE P1547.1 procedures. The ASCO system interconnects synchronous generators with the electric power system and provides monitoring and control for the generator and grid connection through extensive protective functions. The purpose of this testing is to evaluate and give feedback on the contents of IEEE Draft Standard P1547.1 Conformance Tests Procedures for Equipment Interconnecting Distributed Resources With Electric Power Systems.

Load Frequency Control of AC Microgrid Interconnected Thermal Power System

Science.gov (United States)

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.

LHC Computing Grid Project Launches intAction with International Support. A thousand times more computing power by 2006

CERN Multimedia

2001-01-01

The first phase of the LHC Computing Grid project was approved at an extraordinary meeting of the Council on 20 September 2001. CERN is preparing for the unprecedented avalanche of data that will be produced by the Large Hadron Collider experiments. A thousand times more computer power will be needed by 2006! CERN's need for a dramatic advance in computing capacity is urgent. As from 2006, the four giant detectors observing trillions of elementary particle collisions at the LHC will accumulate over ten million Gigabytes of data, equivalent to the contents of about 20 million CD-ROMs, each year of its operation. A thousand times more computing power will be needed than is available to CERN today. The strategy the collabortations have adopted to analyse and store this unprecedented amount of data is the coordinated deployment of Grid technologies at hundreds of institutes which will be able to search out and analyse information from an interconnected worldwide grid of tens of thousands of computers and storag...

A Wavelet-Based Unified Power Quality Conditioner to Eliminate Wind Turbine Non-Ideality Consequences on Grid-Connected Photovoltaic Systems

Directory of Open Access Journals (Sweden)

Bijan Rahmani

2016-05-01

Full Text Available The integration of renewable power sources with power grids presents many challenges, such as synchronization with the grid, power quality problems and so on. The shunt active power filter (SAPF can be a solution to address the issue while suppressing the grid-end current harmonics and distortions. Nonetheless, available SAPFs work somewhat unpredictably in practice. This is attributed to the dependency of the SAPF controller on nonlinear complicated equations and two distorted variables, such as load current and voltage, to produce the current reference. This condition will worsen when the plant includes wind turbines which inherently produce 3rd, 5th, 7th and 11th voltage harmonics. Moreover, the inability of the typical phase locked loop (PLL used to synchronize the SAPF reference with the power grid also disrupts SAPF operation. This paper proposes an improved synchronous reference frame (SRF which is equipped with a wavelet-based PLL to control the SAPF, using one variable such as load current. Firstly the fundamental positive sequence of the source voltage, obtained using a wavelet, is used as the input signal of the PLL through an orthogonal signal generator process. Then, the generated orthogonal signals are applied through the SRF-based compensation algorithm to synchronize the SAPF’s reference with power grid. To further force the remained uncompensated grid current harmonics to pass through the SAPF, an improved series filter (SF equipped with a current harmonic suppression loop is proposed. Concurrent operation of the improved SAPF and SF is coordinated through a unified power quality conditioner (UPQC. The DC-link capacitor of the proposed UPQC, used to interconnect a photovoltaic (PV system to the power grid, is regulated by an adaptive controller. Matlab/Simulink results confirm that the proposed wavelet-based UPQC results in purely sinusoidal grid-end currents with total harmonic distortion (THD = 1.29%, which leads to high

Profitability of smart grid solutions applied in power grid

Directory of Open Access Journals (Sweden)

Katić Nenad A.

2016-01-01

Full Text Available The idea of a Smart Grid solution has been developing for years, as complete solution for a power utility, consisting of different advanced technologies aimed at improving of the efficiency of operation. The trend of implementing various smart systems continues, e.g. Energy Management Systems, Grid Automation Systems, Advanced Metering Infrastructure, Smart power equipment, Distributed Energy Resources, Demand Response systems, etc. Futhermore, emerging technologies, such as energy storages, electrical vehicles or distributed generators, become integrated in distribution networks and systems. Nowadays, the idea of a Smart Grid solution becomes more realistic by full integration of all advanced operation technologies (OT within IT environment, providing the complete digitalization of an Utility (IT/OT integration. The overview of smart grid solutions, estimation of investments, operation costs and possible benefits are presented in this article, with discusison about profitability of such systems.

Analysis of Energy and Power Generation in a Photovoltaic Micro installation Interconnected with a Low Voltage Grid

Directory of Open Access Journals (Sweden)

Marian Sobierajski

2015-12-01

Full Text Available The paper discusses the performance of the 15 kW photovoltaic micro installation located on the roof of building D-1 of the Faculty of Electrical Engineering at Wroclaw University of Technology. The micro installation is connected to the low voltage grid, which supplies the new, air-conditioned building D-20. The paper discusses the energy and power generation output in yearly, monthly, and daily intervals. The micro installation’s output in the summer morning peaks is compared with the daily wind generation against the background of the demand, generation, regulation reserve, and overhauls in the National Power System.

Integration of large wind farms into weak power grids. Emphasis on the Ethiopian interconnected system (ICS)

Energy Technology Data Exchange (ETDEWEB)

Bantyirga Gessesse, Belachew

2013-07-18

The impact of increased wind power on the steady state and dynamic behavior of the Ethiopian power system is the main focus of this thesis. The integration of wind power to the existing grid with conventional generators introduces new set of challenges regarding system security and operational planning, the main cause of the difference arising from the uncertainty of the primary source of energy and the response time following a disturbance. For incorporating wind turbine models into the overall dynamic model of the system and investigating the effect of wind on the dynamic behavior of the wind first models of wind turbine components were put together by reviewing the current state of the art in wind turbine modeling and control concepts. The theoretical insight thus gained was applied to the Ethiopian power system as a case study. Since the models of the installed turbines were either not available or incomplete, an alternative modeling approach based on generic models was adopted. The generic model, in addition to obviating the need for technology or manufacturer specific models, reduces the complexity the dynamic model. Using this procedure, generic dynamic models for wind farm in the system were developed. The capability of dynamic models to reproduce the dynamic response of the system has been verified by comparing simulation results obtained with a detailed and generic wind farm model. It could be shown that the generic wind turbine model is simple, but accurate enough to represent any wind turbine types or entire wind farms for power system stability analysis. The next task was the study of the effect of increased wind power level on the general behavior of the Ethiopian system. It is observed that overall the impact of wind turbines on the operational indices of the system was -as could be expected- more pronounced in the vicinity of the wind farm. But the power angle oscillation following a disturbance was observed across the whole system. Further, as a

Environmental Regulation Impacts on Eastern Interconnection Performance

Energy Technology Data Exchange (ETDEWEB)

Markham, Penn N [ORNL; Liu, Yilu [ORNL; Young II, Marcus Aaron [ORNL

2013-07-01

In the United States, recent environmental regulations will likely result in the removal of nearly 30 GW of oil and coal-fired generation from the power grid, mostly in the Eastern Interconnection (EI). The effects of this transition on voltage stability and transmission line flows have previously not been studied from a system-wide perspective. This report discusses the results of power flow studies designed to simulate the evolution of the EI over the next few years as traditional generation sources are replaced with environmentally friendlier ones such as natural gas and wind.

Research on a Small Signal Stability Region Boundary Model of the Interconnected Power System with Large-Scale Wind Power

Directory of Open Access Journals (Sweden)

Wenying Liu

2015-03-01

Full Text Available For the interconnected power system with large-scale wind power, the problem of the small signal stability has become the bottleneck of restricting the sending-out of wind power as well as the security and stability of the whole power system. Around this issue, this paper establishes a small signal stability region boundary model of the interconnected power system with large-scale wind power based on catastrophe theory, providing a new method for analyzing the small signal stability. Firstly, we analyzed the typical characteristics and the mathematic model of the interconnected power system with wind power and pointed out that conventional methods can’t directly identify the topological properties of small signal stability region boundaries. For this problem, adopting catastrophe theory, we established a small signal stability region boundary model of the interconnected power system with large-scale wind power in two-dimensional power injection space and extended it to multiple dimensions to obtain the boundary model in multidimensional power injection space. Thirdly, we analyzed qualitatively the topological property’s changes of the small signal stability region boundary caused by large-scale wind power integration. Finally, we built simulation models by DIgSILENT/PowerFactory software and the final simulation results verified the correctness and effectiveness of the proposed model.

Distributed Power System Virtual Inertia Implemented by Grid-Connected Power Converters

DEFF Research Database (Denmark)

Fang, Jingyang; Li, Hongchang; Tang, Yi

2018-01-01

Renewable energy sources (RESs), e.g. wind and solar photovoltaics, have been increasingly used to meet worldwide growing energy demands and reduce greenhouse gas emissions. However, RESs are normally coupled to the power grid through fast-response power converters without any inertia, leading...... to decreased power system inertia. As a result, the grid frequency may easily go beyond the acceptable range under severe frequency events, resulting in undesirable load-shedding, cascading failures, or even large-scale blackouts. To address the ever-decreasing inertia issue, this paper proposes the concept...... of distributed power system virtual inertia, which can be implemented by grid-connected power converters. Without modifications of system hardware, power system inertia can be emulated by the energy stored in the dc-link capacitors of grid-connected power converters. By regulating the dc-link voltages...

Scandinavian interconnections as a means for an integrated and sustainable European system

International Nuclear Information System (INIS)

Hedenstedt, A.; Hansson, B.

1996-01-01

After the national grids had been established the comprehensive integration of the Nordic countries took place during a 20 year's period that started in early 1960's. A characteristic feature of the interconnection of the Nordic electric power systems is the need for long HVDC submarine cables for several of the interconnection links. Today the Nordel system is almost considered as one system. At present there are several ongoing, actively considered and planned projects for the integration of the Nordel system and the UCPTE system. The interconnection links offer a number of benefits for both the systems. One very important benefit is the stabilisation effect on the power supply security and the price for electricity. This is of special importance in view of the expected de-regulation of the electricity market. (author)

Power system voltage stability and agent based distribution automation in smart grid

Science.gov (United States)

Nguyen, Cuong Phuc

2011-12-01

Our interconnected electric power system is presently facing many challenges that it was not originally designed and engineered to handle. The increased inter-area power transfers, aging infrastructure, and old technologies, have caused many problems including voltage instability, widespread blackouts, slow control response, among others. These problems have created an urgent need to transform the present electric power system to a highly stable, reliable, efficient, and self-healing electric power system of the future, which has been termed "smart grid". This dissertation begins with an investigation of voltage stability in bulk transmission networks. A new continuation power flow tool for studying the impacts of generator merit order based dispatch on inter-area transfer capability and static voltage stability is presented. The load demands are represented by lumped load models on the transmission system. While this representation is acceptable in traditional power system analysis, it may not be valid in the future smart grid where the distribution system will be integrated with intelligent and quick control capabilities to mitigate voltage problems before they propagate into the entire system. Therefore, before analyzing the operation of the whole smart grid, it is important to understand the distribution system first. The second part of this dissertation presents a new platform for studying and testing emerging technologies in advanced Distribution Automation (DA) within smart grids. Due to the key benefits over the traditional centralized approach, namely flexible deployment, scalability, and avoidance of single-point-of-failure, a new distributed approach is employed to design and develop all elements of the platform. A multi-agent system (MAS), which has the three key characteristics of autonomy, local view, and decentralization, is selected to implement the advanced DA functions. The intelligent agents utilize a communication network for cooperation and

National power grid simulation capability : need and issues

Energy Technology Data Exchange (ETDEWEB)

Petri, Mark C. [Argonne National Lab. (ANL), Argonne, IL (United States)

2009-06-02

On December 9 and 10, 2008, the Department of Homeland Security (DHS) Science and Technology Directorate sponsored a national workshop at Argonne National Laboratory to explore the need for a comprehensive modeling and simulation capability for the national electric power grid system. The workshop brought together leading electric power grid experts from federal agencies, the national laboratories, and academia to discuss the current state of power grid science and engineering and to assess if important challenges are being met. The workshop helped delineate gaps between grid needs and current capabilities and identify issues that must be addressed if a solution is to be implemented. This report is a result of the workshop and highlights power grid modeling and simulation needs, the barriers that must be overcome to address them, and the benefits of a national power grid simulation capability.

Interconnecting Microgrids via the Energy Router with Smart Energy Management

Directory of Open Access Journals (Sweden)

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.

The evolution of the electric power grid within the energy transition. Breakfast of 8 February 2017

International Nuclear Information System (INIS)

Prins, Katrien; ); Bendtsen, Bendt; ); Derdevet, Michel; Duerr, Matthias; Laffaye, Herve

2017-01-01

This document proposes a synthesis of contributions, questions and answers of a meeting gathering French and Danish representatives of political parties, electric utilities and European bodies which addressed issues related to the evolution of the electric power grid within a context of energy transition. Several issues have been addressed. First, the approach adopted by institutional actors like the European Commission and Parliament with a priority given to grid infrastructures to ensure interconnection between all member States, a financial support for the associated investments, and a European governance. Second, the approach adopted by operators in charge of networks, transport and distribution to face a change in the business model, an increasing financial burden, the issue of acceptability of works, future evolutions and innovations, and a closer collaboration

Optimal Power Transmission of Offshore Wind Power Using a VSC-HVdc Interconnection

Directory of Open Access Journals (Sweden)

Miguel E. Montilla-DJesus

2017-07-01

Full Text Available High-voltage dc transmission based on voltage-source converter (VSC-HVdc is quickly increasing its power rating, and it can be the most appropriate link for the connection of offshore wind farms (OWFs to the grid in many locations. This paper presents a steady-state operation model to calculate the optimal power transmission of an OWF connected to the grid through a VSC-HVdc link. The wind turbines are based on doubly fed induction generators (DFIGs, and a detailed model of the internal OWF grid is considered in the model. The objective of the optimization problem is to maximize the active power output of the OWF, i.e., the reduction of losses, by considering the optimal reactive power allocation while taking into account the restrictions imposed by the available wind power, the reactive power capability of the DFIG, the DC link model, and the operating conditions. Realistic simulations are performed to evaluate the proposed model and to execute optimal operation analyses. The results show the effectiveness of the proposed method and demonstrate the advantages of using the reactive control performed by DFIG to achieve the optimal operation of the VSC-HVdc.

Synchronization of grid-connected renewable energy sources under highly distorted voltages and unbalanced grid faults

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

2013-01-01

Renewable energy sources require accurate and appropriate performance not only under normal grid operation but also under abnormal and faulty grid conditions according to the modern grid codes. This paper proposes a novel phase-locked loop algorithm (MSHDC-PLL), which can enable the fast...... and dynamic synchronization of the interconnected renewable energy system under unbalanced grid faults and under highly harmonic distorted voltage. The outstanding performance of the suggested PLL is achieved by implementing an innovative multi-sequence/harmonic decoupling cell in order to dynamically cancel...... renewable energy systems. Therefore, the performance of the new PLL can increase the quality of the injected power under abnormal conditions and in addition enable the renewable energy systems to provide the appropriate support to the grid under balanced and unbalanced grid faults....

Energy conservation through the implementation of cogeneration and grid interconnection

International Nuclear Information System (INIS)

Dashash, M. A.

2007-01-01

With increasing awareness of energy conservation and environmental protection, the Arab World is moving to further improve energy conversion efficiency. The equivalent of over 2.7 MM bbl is being daily burnt to fuel the thermal power plants that represent 92% of the total Arab power generation. This adds up to close to one billion barrels annually. At a conservative 30$ per barrel, this represents a daily cost of over $81 Million. This paper will introduce two strategies with the ultimate objective to cut-off up to half of the current fuel consumption. Firstly, Cogeneration Technology is able to improve thermal efficiency from the current average of less than 25% to up to 80%. Just 1% improvement in power plant thermal efficiency represents 3 million $/day in fuel cost savings. In addition, a well-designed and operated cogeneration plant will: - Reduce unfriendly emissions by burning less fuel as a result of higher thermal efficiency, - Increase the decentralization of electrical generation, - Improve the reliability of electricity supply. As an example, the Kingdom of Saudi Arabia's experience of implementing cogeneration will be presented, in particular within its hydrocarbon facilities and desalination plants. This will include the existing facilities and the planned and on-going projects. Secondly, by interconnecting the power networks of all the adjacent Arab countries, the following benefits could be reached: - Reduce generation reserves and enhance the system reliability, - Improve the economic efficiency of the electricity power systems, - Provide power exchange and strengthen the supply reliability, - Adopt technological development and use the best modern technologies. At least two factors plead for this direction. On one hand, the four-hour time zone difference from Eastern to Western Arab World makes it easy to exchange power. On the other hand, this will help to reduce the reserve capacity and save on corresponding Capital investment, fuel, and O and M

Overcoming PV grid issues in the urban areas

Energy Technology Data Exchange (ETDEWEB)

Ehara, T.

2009-10-15

This report for the International Energy Agency (IEA) made by Task 10 of the Photovoltaic Power Systems (PVPS) programme takes a look at grid issues in urban photovoltaic electricity and how to overcome them. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy as a significant and sustainable renewable energy option. The objective of Task 10 is stated as being to enhance the opportunities for wide-scale, solution-oriented application of photovoltaics in the urban environment. The paper discusses the goal of mainstreaming PV systems in the urban environment. In this report, PV grid interconnection issues and countermeasures based on the latest studies are identified and summarised. Appropriate and understandable information is provided for all possible stakeholders. Possible impacts and benefits of PV grid interconnection are identified, technical measures designed to eliminate negative impacts and enhance possible benefits are presented. The status of research and demonstration projects is introduced and the latest outcomes are summarised. Recommendations and conclusions based on the review process are summarised and presented.

Fuel Cell Backup Power System for Grid Service and Micro-Grid in Telecommunication Applications: Preprint

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhiwen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Eichman, Joshua D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kurtz, Jennifer M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-03-22

This paper presents the feasibility and economics of using fuel cell backup power systems in telecommunication cell towers to provide grid services (e.g., ancillary services, demand response). The fuel cells are able to provide power for the cell tower during emergency conditions. This study evaluates the strategic integration of clean, efficient, and reliable fuel cell systems with the grid for improved economic benefits. The backup systems have potential as enhanced capability through information exchanges with the power grid to add value as grid services that depend on location and time. The economic analysis has been focused on the potential revenue for distributed telecommunications fuel cell backup units to provide value-added power supply. This paper shows case studies on current fuel cell backup power locations and regional grid service programs. The grid service benefits and system configurations for different operation modes provide opportunities for expanding backup fuel cell applications responsive to grid needs.

A Design of a 345-kV Electric Power Transmission Line Interlinking Ramu and Rouna Grids in Papua New Guinea

Directory of Open Access Journals (Sweden)

Sakato Francis

2017-01-01

Full Text Available According to PNG Power Limited (PPL, Papua New Guinea’s peak power demand is expected to increase from 210 MW in 2012 to 347 MW in 2026. Under the current state of the power sector in Papua New Guinea (PNG, it is critical to implement measures to cope with the increasing power demand to promote investment, economic growth, and ultimately to achieve poverty reduction through economic growth. One of the solutions identified to improve the reliability of PNG power systems and thus to meet the demand is to interconnect the major grids in the country so that the loads could be shared among them. This project embarks in designing a 345-kV electric power transmission line to interlink the Ramu and Rouna power grids of Papua New Guinea. The design is done by analysing all the necessary aspects of the transmission lines with in-depth calculations performed using MATHCAD software. This design is the basis for extra-high voltage (EHV transmission network in anticipation for the power generation and demand growth in PNG.

A Grid Voltage Measurement Method for Wind Power Systems during Grid Fault Conditions

OpenAIRE

Yoo, Cheol-Hee; Chung, Il-Yop; Yoo, Hyun-Jae; Hong, Sung-Soo

2014-01-01

Grid codes in many countries require low-voltage ride-through (LVRT) capability to maintain power system stability and reliability during grid fault conditions. To meet the LVRT requirement, wind power systems must stay connected to the grid and also supply reactive currents to the grid to support the recovery from fault voltages. This paper presents a new fault detection method and inverter control scheme to improve the LVRT capability for full-scale permanent magnet synchronous generator (P...

Grid synchronization for advanced power processing and FACTS in wind power systems

DEFF Research Database (Denmark)

Luna, A.; Rocabert, J.; Vazquez, G.

2010-01-01

The high penetration of wind power systems in the electrical network has introduced new issues in the stability and transient operation of the grid. By means of providing advanced functionalities to the existing power converters of such power plants it is possible to enhance their performance...... and also to support the grid operation, as the new grid codes demand. The connection of FACTS based on power converters, such as STATCOMs, are also contributing to the integration of renewable energies improving their behavior under contingencies. However, in both cases it is needed to have a grid voltage...

IEEE 1547 and 2030 Standards for Distributed Energy Resources Interconnection and Interoperability with the Electricity Grid

Energy Technology Data Exchange (ETDEWEB)

Basso, T.

2014-12-01

Public-private partnerships have been a mainstay of the U.S. Department of Energy and the National Renewable Energy Laboratory (DOE/NREL) approach to research and development. These partnerships also include technology development that enables grid modernization and distributed energy resources (DER) advancement, especially renewable energy systems integration with the grid. Through DOE/NREL and industry support of Institute of Electrical and Electronics Engineers (IEEE) standards development, the IEEE 1547 series of standards has helped shape the way utilities and other businesses have worked together to realize increasing amounts of DER interconnected with the distribution grid. And more recently, the IEEE 2030 series of standards is helping to further realize greater implementation of communications and information technologies that provide interoperability solutions for enhanced integration of DER and loads with the grid. For these standards development partnerships, for approximately $1 of federal funding, industry partnering has contributed $5. In this report, the status update is presented for the American National Standards IEEE 1547 and IEEE 2030 series of standards. A short synopsis of the history of the 1547 standards is first presented, then the current status and future direction of the ongoing standards development activities are discussed.

Grid-wide subdaily hydrologic alteration under massive wind power penetration in Chile.

Science.gov (United States)

Haas, J; Olivares, M A; Palma-Behnke, R

2015-05-01

Hydropeaking operations can severely degrade ecosystems. As variable renewable sources (e.g. wind power) are integrated into a power grid, fluctuations in the generation-demand balance are expected to increase. In this context, compensating technologies, notably hydropower reservoir plants, could operate in a stronger peaking scheme. This issue calls for an integrated modeling of the entire power system, including not only hydropower reservoirs, but also all other plants. A novel methodology to study the link between the short-term variability of renewable energies and the subdaily hydrologic alteration, due to hydropower reservoir operations is presented. Grid operations under selected wind power portfolios are simulated using a short-term hydro-thermal coordination tool. The resulting turbined flows by relevant reservoir plants are then compared in terms of the Richard-Baker flashiness index to both the baseline and the natural flow regime. Those are then analyzed in order to: i) detect if there is a significant change in the degree of subdaily hydrologic alteration (SDHA) due to a larger wind penetration, and ii) identify which rivers are most affected. The proposed scheme is applied to Chile's Central Interconnect System (SIC) for scenarios up to 15% of wind energy penetration. Results show a major degree of SDHA under the baseline as compared to the natural regime. As wind power increases, so does the SDHA in two important rivers. This suggests a need for further ecological studies in those rivers, along with an analysis of operational constraints to limit the SDHA. Copyright © 2015 Elsevier Ltd. All rights reserved.

Environmental report 2001 - Verbund Austria Power Grid

International Nuclear Information System (INIS)

2002-01-01

A balance of the environmental activities performed by Verbund Austria Power Grid during 2001 is presented. It comprises which measures were taken to reach their environmental objectives: certification of an environmental management system according to ISO 14001 and EMAS, environmental protection, policies, water and thermoelectric power generation status ( CO 2 , SO 2 , NO x emission monitoring, energy efficiency, replacement of old equipment), reduction of the greenhouse gases emissions and nature conservation. The report is divided in 8 sections: power grid, environmental policy, environmental management, power grid layout, environmental status of the system, introduction of new technologies for environmental monitoring, environmental objectives 2001 - 2002, and data and facts 2001. (nevyjel)

Power grid complexity

Energy Technology Data Exchange (ETDEWEB)

Mei, Shengwei; Zhang, Xuemin [Tsinghua Univ., Beijing, BJ (China). Dept. of Electrical Engineering; Cao, Ming [Groningen Univ. (Netherlands). Faculty of Mathematics and Natural Sciences

2011-07-01

''Power Grid Complexity'' introduces the complex system theory known as self-organized criticality (SOC) theory and complex network theory, and their applications to power systems. It studies the network characteristics of power systems, such as their small-world properties, structural vulnerability, decomposition and coordination strategies, and simplification and equivalence methods. The book also establishes four blackout models based on SOC theory through which the SOC of power systems is studied at both the macroscopic and microscopic levels. Additionally, applications of complex system theory in power system planning and emergency management platforms are also discussed in depth. This book can serve as a useful reference for engineers and researchers working with power systems. (orig.)

A Grid Voltage Measurement Method for Wind Power Systems during Grid Fault Conditions

Directory of Open Access Journals (Sweden)

Cheol-Hee Yoo

2014-11-01

Full Text Available Grid codes in many countries require low-voltage ride-through (LVRT capability to maintain power system stability and reliability during grid fault conditions. To meet the LVRT requirement, wind power systems must stay connected to the grid and also supply reactive currents to the grid to support the recovery from fault voltages. This paper presents a new fault detection method and inverter control scheme to improve the LVRT capability for full-scale permanent magnet synchronous generator (PMSG wind power systems. Fast fault detection can help the wind power systems maintain the DC-link voltage in a safe region. The proposed fault detection method is based on on-line adaptive parameter estimation. The performance of the proposed method is verified in comparison to the conventional voltage measurement method defined in the IEC 61400-21 standard.

Impact of network topology on synchrony of oscillatory power grids

Energy Technology Data Exchange (ETDEWEB)

Rohden, Martin; Sorge, Andreas; Witthaut, Dirk [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Timme, Marc [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Faculty of Physics, Georg August Universität Göttingen, Göttingen (Germany)

2014-03-15

Replacing conventional power sources by renewable sources in current power grids drastically alters their structure and functionality. In particular, power generation in the resulting grid will be far more decentralized, with a distinctly different topology. Here, we analyze the impact of grid topologies on spontaneous synchronization, considering regular, random, and small-world topologies and focusing on the influence of decentralization. We model the consumers and sources of the power grid as second order oscillators. First, we analyze the global dynamics of the simplest non-trivial (two-node) network that exhibit a synchronous (normal operation) state, a limit cycle (power outage), and coexistence of both. Second, we estimate stability thresholds for the collective dynamics of small network motifs, in particular, star-like networks and regular grid motifs. For larger networks, we numerically investigate decentralization scenarios finding that decentralization itself may support power grids in exhibiting a stable state for lower transmission line capacities. Decentralization may thus be beneficial for power grids, regardless of the details of their resulting topology. Regular grids show a specific sharper transition not found for random or small-world grids.

Smart Grid Technology

OpenAIRE

Cosma Sorinel

2010-01-01

The largest interconnected machine on Earth, the century-old power grid is so massively complex and inextricably linked to human involvement and endeavor that it has been called an ecosystem. To meet sustainability requirements, the electric industry is poised to make the transformation from a centralized, producer-controlled network to one that is less centralized and more consumerinteractive. This move promises to change the industry’s entire business model and its relationship with all sta...

Grid Converters for Stationary Battery Energy Storage Systems

DEFF Research Database (Denmark)

Trintis, Ionut

The integration of renewable energy sources in the power system, with high percentage, is a well known challenge nowadays. Power sources like wind and solar are highly volatile, with uctuations on various time scales. One long term solution is to build a continentwide or worldwide supergrid....... Another solution is to use distributed energy storage units, and create virtual power plants. Stationary energy storage is a complementary solution, which can postpone the network expansion and can be optimized for dierent kind of grid services. As an energy storage solution with timing for few seconds...... multilevel converter structure with integrated energy storage is introduced. This converter structure is suitable to interface low and medium voltage energy storage units to medium and high voltage grids. It can also interconnect a DC and AC grid with bidirectional power ow, were both can be backed...

Cyber security and vulnerability of 'smart' power grids

OpenAIRE

Jovanović, Slobodan

2012-01-01

Smart power grids deliver electric energy from generation to consumers using two-way Smart Meter technology (smart meters), enabling remote control of consumer energy use. However, smart power grids are increasingly very attractive targets for hackers and terrorists. This paper discusses the key characteristics of cyber security/vulnerability of smart power grids, and their communication architecture, and their vulnerability points. Then, it describes guidelines which are needed to be impleme...

Switching overvoltages in offshore wind power grids

DEFF Research Database (Denmark)

Arana Aristi, Ivan

and cables are presented. In Chapter 4 results from time domain measurements and simulations of switching operations in offshore wind power grids are described. Specifically, switching operations on a single wind turbine, the collection grid, the export system and the external grid measured in several real...... offshore wind farms are shown together with simulation results. Switching operations in offshore wind power grids can be simulated with different electromagnetic transient programs. Different programs were used in the project and compared results are included in Chapter 4. Also in Chapter 4 different......Switching transients in wind turbines, the collection grid, the export system and the external grid in offshore wind farms, during normal or abnormal operation, are the most important phenomena when conducting insulation coordination studies. However, the recommended models and methods from...

Regulatory Issues Surrounding Merchant Interconnection

International Nuclear Information System (INIS)

Kuijlaars, Kees-Jan; Zwart, Gijsbert

2003-11-01

We discussed various issues concerning the regulatory perspective on private investment in interconnectors. One might claim that leaving investment in transmission infrastructure to competing market parties is more efficient than relying on regulated investment only (especially in the case of long (DC) lines connecting previously unconnected parts of the grids, so that externalities from e.g. loop flows do not play a significant role). We considered that some aspects of interconnection might reduce these market benefits. In particular, the large fixed costs of interconnection construction may lead to significant under investment (due to both first mover monopoly power and the fact that part of generation cost efficiencies realised by interconnection are not captured by the investor itself, and remain external to the investment decision). Second, merchant ownership restricts future opportunities for adaptation of regulation, as would be required e.g. for introduction of potentially more sophisticated methods of congestion management or market splitting. Some of the disadvantages of merchant investment may be mitigated however by a suitable regulatory framework, and we discussed some views in this direction. The issues we discussed are not intended to give a complete framework, and detailed regulation will certainly involve many more specific requirements. Areas we did not touch upon include e.g. the treatment of deep connection costs, rules for operation and maintenance of the line, and impact on availability of capacity on other interconnections

Regulatory Issues Surrounding Merchant Interconnection

Energy Technology Data Exchange (ETDEWEB)

Kuijlaars, Kees-Jan; Zwart, Gijsbert [Office for Energy Regulation (DTe), The Hague (Netherlands)

2003-11-01

We discussed various issues concerning the regulatory perspective on private investment in interconnectors. One might claim that leaving investment in transmission infrastructure to competing market parties is more efficient than relying on regulated investment only (especially in the case of long (DC) lines connecting previously unconnected parts of the grids, so that externalities from e.g. loop flows do not play a significant role). We considered that some aspects of interconnection might reduce these market benefits. In particular, the large fixed costs of interconnection construction may lead to significant under investment (due to both first mover monopoly power and the fact that part of generation cost efficiencies realised by interconnection are not captured by the investor itself, and remain external to the investment decision). Second, merchant ownership restricts future opportunities for adaptation of regulation, as would be required e.g. for introduction of potentially more sophisticated methods of congestion management or market splitting. Some of the disadvantages of merchant investment may be mitigated however by a suitable regulatory framework, and we discussed some views in this direction. The issues we discussed are not intended to give a complete framework, and detailed regulation will certainly involve many more specific requirements. Areas we did not touch upon include e.g. the treatment of deep connection costs, rules for operation and maintenance of the line, and impact on availability of capacity on other interconnections.

Smart grids and power systems efficiency: regulatory tools and demand-side management impacts

International Nuclear Information System (INIS)

Bergaentzle, Claire

2015-01-01

induced by peak shedding. To this end, we develop and use a linear optimization model and expand our analysis to interconnected countries endowed with differentiated generation means. The thesis shows dominant regulatory frameworks are unsuited to provide the necessary sets of incentive to efficiently develop smart technologies. This can cause delays in their integration to power grids. The quantitative evaluation of the impacts generated by demand-side management shows significant efficiency gains are achievable through final consumers' flexibility. However, such measures create new discrepancies regarding installed capacities profitability, future capacity adequacy, and highlight potential antagonism between missing money for flexible peak capacities and the development of low carbon energies. It is clear the issues raised by the development of smart grids call for informed public debate as power industries are essential to our societies. Among the considerable amount of elements to discuss, issues relative to financing the investment projects and the inclusion of the new sources of flexibility induced by the technology in competitive markets will be of priority. (author) [fr

Solar activity and economic fundamentals: Evidence from 12 geographically disparate power grids

Science.gov (United States)

Forbes, Kevin F.; St. Cyr, O. C.

2008-10-01

This study uses local (ground-based) magnetometer data as a proxy for geomagnetically induced currents (GICs) to address whether there is a space weather/electricity market relationship in 12 geographically disparate power grids: Eirgrid, the power grid that serves the Republic of Ireland; Scottish and Southern Electricity, the power grid that served northern Scotland until April 2005; Scottish Power, the power grid that served southern Scotland until April 2005; the power grid that serves the Czech Republic; E.ON Netz, the transmission system operator in central Germany; the power grid in England and Wales; the power grid in New Zealand; the power grid that serves the vast proportion of the population in Australia; ISO New England, the power grid that serves New England; PJM, a power grid that over the sample period served all or parts of Delaware, Maryland, New Jersey, Ohio, Pennsylvania, Virginia, West Virginia, and the District of Columbia; NYISO, the power grid that serves New York State; and the power grid in the Netherlands. This study tests the hypothesis that GIC levels (proxied by the time variation of local magnetic field measurements (dH/dt)) and electricity grid conditions are related using Pearson's chi-squared statistic. The metrics of power grid conditions include measures of electricity market imbalances, energy losses, congestion costs, and actions by system operators to restore grid stability. The results of the analysis indicate that real-time market conditions in these power grids are statistically related with the GIC proxy.

Frequency Stabilizing Scheme for a Danish Island Grid

DEFF Research Database (Denmark)

Cha, Seung-Tae; Wu, Qiuwei; Østergaard, Jacob

2012-01-01

of wind power is necessary to avoid unwanted power oscillations, which lead to uncontrolled oscillations in the power plant control. Since this might deteriorate power quality including frequency in an island grid, a frequency stabilizing control scheme or strategies using intelligent controller......This paper describes the development of frequency stabilizing control scheme for a small Danish island of Bornholm. The Bornholm power system is able to transit from interconnected operation with the Nordic power system to isolated islanding operation. During islanding operation the shedding...... with a battery energy storage system (BESS) has been proposed. The real-time models of distribution grids of Bornholm power system were used to carry out case studies to illustrate the performance of centralized load frequency control as well as coordinated control scheme. Case study results show...

Models and methods for assessing the value of HVDC and MVDC technologies in modern power grids

Energy Technology Data Exchange (ETDEWEB)

Makarov, Yuri V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); O' Brien, James G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Qiuhua [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kirkham, Harold [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Zhenyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chinthavali, Madhu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Suman, Debnath [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mohan, Nihal [Mid-Continent Independent System Operator (MISO), St. Paul, MN (United States); Hess, Warren [Mid-Continent Independent System Operator (MISO), St. Paul, MN (United States); Duebner, David [Mid-Continent Independent System Operator (MISO), St. Paul, MN (United States); Orser, David [Mid-Continent Independent System Operator (MISO), St. Paul, MN (United States); Brown, Hilary [Mid-Continent Independent System Operator (MISO), St. Paul, MN (United States); Osborn, Dale [Mid-Continent Independent System Operator (MISO), St. Paul, MN (United States); Feltes, James [Siemens, Knoxville, TN (United States); Kurthakoti Chandrashekhara, Divya [Siemens, Knoxville, TN (United States); Zhu, Wenchun [Siemens, Knoxville, TN (United States)

2017-07-31

This report reflects the results of U.S. Department of Energy’s (DOE) Grid Modernization project 0074 “Models and methods for assessing the value of HVDC [high-voltage direct current] and MTDC [multi-terminal direct current] technologies in modern power grids.” The work was done by the Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) in cooperation with Mid-Continent Independent System Operator (MISO) and Siemens. The main motivation of this study was to show the benefit of using direct current (DC) systems larger than those in existence today as they overlap with the alternating current (AC) systems. Proper use of their flexibility in terms of active/reactive power control and fast response can provide much-needed services to the grid at the same time as moving large blocks of energy to take advantage of cost diversity. Ultimately, the project’s success will enable decision-makers and investors to make well-informed decisions regarding this use of DC systems. This project showed the technical feasibility of HVDC macrogrid for frequency control and congestion relief in addition to bulk power transfers. Industry-established models for commonly used technologies were employed, along with high-fidelity models for recently developed HVDC converter technologies; like the modular multilevel converters (MMCs), a voltage source converters (VSC). Models for General Electric Positive Sequence Load Flow (GE PSLF) and Siemens Power System Simulator (PSS/E), widely used analysis programs, were for the first time adapted to include at the same time both Western Electricity Coordinating Council (WECC) and Eastern Interconnection (EI), the two largest North American interconnections. The high-fidelity models and their control were developed in detail for MMC system and extended to HVDC systems in point-to-point and in three-node multi-terminal configurations. Using a continental-level mixed AC-DC grid model, and using a HVDC macrogrid

Comparative Analysis and Considerations for PV Interconnection Standards in the United States and China

Energy Technology Data Exchange (ETDEWEB)

None

2017-01-01

The main objectives of this report are to evaluate China's photovoltaic (PV) interconnection standards and the U.S. counterparts and to propose recommendations for future revisions to these standards. This report references the 2013 report Comparative Study of Standards for Grid-Connected PV System in China, the U.S. and European Countries, which compares U.S., European, and China's PV grid interconnection standards; reviews various metrics for the characterization of distribution network with PV; and suggests modifications to China's PV interconnection standards and requirements. The recommendations are accompanied by assessments of four high-penetration PV grid interconnection cases in the United States to illustrate solutions implemented to resolve issues encountered at different sites. PV penetration in China and in the United States has significantly increased during the past several years, presenting comparable challenges depending on the conditions of the grid at the point of interconnection; solutions are generally unique to each interconnected PV installation or PV plant.

Interconnection issues in Ontario : a status check

International Nuclear Information System (INIS)

Helbronner, V.

2010-01-01

This PowerPoint presentation discussed wind and renewable energy interconnection issues in Ontario. The province's Green Energy Act established a feed-in tariff (FIT) program and provided priority connection access to the electricity system for renewable energy generation facilities that meet regulatory requirements. As a result of the province's initiatives, Hydro One has identified 20 priority transmission expansion projects and is focusing on servicing renewable resource clusters. As of October 2010, the Ontario Power Authority (OPA) has received 1469 MW of FIT contracts executed for wind projects. A further 5953 MW of wind projects are awaiting approval. A Korean consortium is now planning to develop 2500 MW of renewable energy projects in the province. The OPA has also been asked to develop an updated transmission expansion plan. Transmission/distribution availability tests (TAT/DAT) have been established to determine if there is sufficient connection availability for FIT application projects. Economic connection tests (ECTs) are conducted to assess whether grid upgrade costs to enable additional FIT capacity are justifiable. When projects pass the ECT, grid upgrades needed for the connection included in grid expansion plans. Ontario's long term energy plan was also reviewed. tabs., figs.

Structural Emergency Control for Power Grids

DEFF Research Database (Denmark)

Vu, Thanh Long; Chatzivasileiadis, Spyros; Chiang, Hsiao-Dong

2017-01-01

In this paper, we introduce a structural emergency control to render post-fault dynamics of power systems from the critical fault-cleared state to a stable equilibrium point (EP). Theoretically, this is a new control paradigm that does not rely on any continuous measurement or load shedding......, as in the classical setup. Instead, the grid is made stable by intentionally changing the power network structure, and thereby, discretely relocating the EP and its stability region such that the system is consecutively driven from fault-cleared state through a set of EPs to the desired EP. The proposed control...... is designed by solving convex optimization problems, making it possibly scalable to large-scale power grids. In the practical side, the proposed control can be implemented by exploiting the FACTS devices that will be widely available on the grids, and hence, requiring minor investment....

Grid Support in Large Scale PV Power Plants using Active Power Reserves

DEFF Research Database (Denmark)

Craciun, Bogdan-Ionut

to validate the performance of the frequency support functions, a flexible grid model with IEEE 12 bus system characteristics has been developed and implemented in RTDS. A power hardware-in-the-loop (PHIL) system composed by 20 kW plant (2 x 10 kW inverters and PV linear simulator) and grid simulator (RTDS......Photovoltaic (PV) systems are in the 3rd place in the renewable energy market, after hydro and wind power. The increased penetration of PV within the electrical power system has led to stability issues of the entire grid in terms of its reliability, availability and security of the supply....... As a consequence, Large scale PV Power Plants (LPVPPs) operating in Maximum Power Point (MPP) are not supporting the electrical network, since several grid triggering events or the increased number of downward regulation procedures have forced European Network of Transmission System Operators for Electricity...

A Survey on Next-generation Power Grid Data Architecture

Energy Technology Data Exchange (ETDEWEB)

You, Shutang [University of Tennessee, Knoxville (UTK); Zhu, Dr. Lin [University of Tennessee (UT); Liu, Yong [ORNL; Liu, Yilu [ORNL; Shankar, Mallikarjun (Arjun) [ORNL; Robertson, Russell [Grid Protection Alliance; King Jr, Thomas J [ORNL

2015-01-01

The operation and control of power grids will increasingly rely on data. A high-speed, reliable, flexible and secure data architecture is the prerequisite of the next-generation power grid. This paper summarizes the challenges in collecting and utilizing power grid data, and then provides reference data architecture for future power grids. Based on the data architecture deployment, related research on data architecture is reviewed and summarized in several categories including data measurement/actuation, data transmission, data service layer, data utilization, as well as two cross-cutting issues, interoperability and cyber security. Research gaps and future work are also presented.

Agreement between Autorita per l'energia elettrica e il gas and commission de regulation de l'electricite on transfer capacity allocation over the grid interconnecting Italy and France for the year 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

The present document contains the general outlines adopted by the Autorita per l'energia elettrica e il gas (hereafter AEEG) and the Commission de Regulation de l'Electricite (hereafter CRE) with respect to terms and conditions for allocating the transfer capacity over the interconnected grid between Italy, France and, with reference to a technically-coupled portion of the interconnection, Switzerland for the year 2002. Same conditions will be applied by AEEG, to a possible extent, to the transfer capacity allocation over the interconnected grid between Italy. Austria and Slovenia for the year 2002.

Economics of Wind Power when National Grids are Unreliable

NARCIS (Netherlands)

Kooten, van G.C.; Wong, L.

2010-01-01

Power interruptions are a typical characteristic of national grids in developing countries. Manufacturing, processing, refrigeration and other facilities that require a dependable supply of power, and might be considered a small grid within the larger national grid, employ diesel generators for

Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

Energy Technology Data Exchange (ETDEWEB)

McDowell, Jason (General Electric, Schenectady, NY); Walling, Reigh (General Electric, Schenectady, NY); Peter, William (SunPower, Richmond, CA); Von Engeln, Edi (NV Energy, Reno, NV); Seymour, Eric (AEI, Fort Collins, CO); Nelson, Robert (Siemens Wind Turbines, Orlando, FL); Casey, Leo (Satcon, Boston, MA); Ellis, Abraham; Barker, Chris. (SunPower, Richmond, CA)

2012-02-01

Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.

Control of Power and Voltage of Solar Grid Connected

OpenAIRE

Allah, Boucetta Abd; Djamel, Labed

2016-01-01

Renewable energy is high on International agendas. Currently, grid-connected photovoltaic systems are a popular technology to convert solar energy into electricity. Control of power injected into the grid, maximum power point, high efficiency, and low total harmonic distortion of the currents injected into the grid are the requirements for inverter connection into the grid. Consequently, the performance of the inverters connected to the grid depends largely on the control strategy applied. In...

Overvoltages related to distributed generation-power system interconnection transformer

Energy Technology Data Exchange (ETDEWEB)

Zamanillo, G.R.; Gomez, J.C.; Florena, E.F. [Rio Cuarto National University (IPSEP/UNRC), Cordoba (Argentina). Electric Power Systems Protection Institute], Email: jcgomez@ing.unrc.edu.ar

2009-07-01

The energy crisis that experiences the world drives to carry to an extreme, the use of all energy sources which are available. The sources need to be connected to the electric network in their next point, requiring of electric-electronic interfaces. The traditional electric power systems are changing their characteristics, in what concerns to structure, operation and on overvoltage generation. This change is not taking place in coordinated form among the involved sectors. The interconnection of a Distributed Generator (DG) directly with the power system is objectionable and risky. It is required of an interconnection transformer which performs several functions. Rigid specifications do not exist in this respect, for the variety of systems in use in the world, nevertheless there are utilities recommendations. Overvoltages caused by the DG, which arise due to the change of structure of the electric system, are explained. The transformer connection selection, presents positive and negative aspects that impact the utility and the user in a different or many times in an antagonistic way. The phenomenon of balanced and unbalanced ferroresonance overvoltage is studied. This phenomenon can takes place when using DG, either with synchronous or asynchronous generator, and for any type of connection of the transformer. The necessary conditions so that the phenomenon appears are presented. Eight interconnection transformer connection ways were studied. It is concluded that the solutions to reach by means of the employment of the DG, offer technical-economic advantages so much to the utility as to the user. It is also concluded in this work that the more advisable interconnection type is function of the system connection type. (author)

Conference on renewable energies integration to power grids

International Nuclear Information System (INIS)

Laffaille, Didier; Bischoff, Torsten; Merkel, Marcus; Rohrig, Kurt; Glatigny, Alain; Quitmann, Eckard; Lehec, Guillaume; Teirlynck, Thierry; Stahl, Oliver

2014-01-01

The French-German office for Renewable energies (OFAEnR) organised a conference on renewable energies integration to power grids. In the framework of this French-German exchange of experience, more than 150 participants exchanged views on the perspectives and possible solutions of this integration in order to warrant the security of supplies and the grid stability in a context of increasing injection and decentralization of renewable power sources. This document brings together the available presentations (slides) made during this event: 1 - French distribution grids - Overview and perspectives (Didier Laffaille); 2 - Distribution Grids in Germany - Overview and Perspective (Torsten Bischoff); 3 - Integration of renewable energies into distribution grids - a case example from Germany (Marcus Merkel); 4 - Regeneratives Kombikraftwerk Deutschland: System Services with 100 % Renewable energies (Kurt Rohrig); 5 - Overview of the different grid instrumentation-control and automation tools (Alain Glatigny); 6 - Which Ancillary Services needs the Power System? The contribution from Wind Power Plants (Eckard Quitmann); 7 - The Flexibility Aggregator - the example of the GreenLys Project (Guillaume Lehec); 8 - Energy Pool - Providing flexibility to the electric system. Consumption cut-off solutions in France (Thierry Teirlynck); 9 - Demand Response experiences from Germany (Oliver Stahl)

Hardware-in-the-loop grid simulator system and method

Science.gov (United States)

Fox, John Curtiss; Collins, Edward Randolph; Rigas, Nikolaos

2017-05-16

A hardware-in-the-loop (HIL) electrical grid simulation system and method that combines a reactive divider with a variable frequency converter to better mimic and control expected and unexpected parameters in an electrical grid. The invention provides grid simulation in a manner to allow improved testing of variable power generators, such as wind turbines, and their operation once interconnected with an electrical grid in multiple countries. The system further comprises an improved variable fault reactance (reactive divider) capable of providing a variable fault reactance power output to control a voltage profile, therein creating an arbitrary recovery voltage. The system further comprises an improved isolation transformer designed to isolate zero-sequence current from either a primary or secondary winding in a transformer or pass the zero-sequence current from a primary to a secondary winding.

About the Need of Combining Power Market and Power Grid Model Results for Future Energy System Scenarios

Science.gov (United States)

Mende, Denis; Böttger, Diana; Löwer, Lothar; Becker, Holger; Akbulut, Alev; Stock, Sebastian

2018-02-01

The European power grid infrastructure faces various challenges due to the expansion of renewable energy sources (RES). To conduct investigations on interactions between power generation and the power grid, models for the power market as well as for the power grid are necessary. This paper describes the basic functionalities and working principles of both types of models as well as steps to couple power market results and the power grid model. The combination of these models is beneficial in terms of gaining realistic power flow scenarios in the grid model and of being able to pass back results of the power flow and restrictions to the market model. Focus is laid on the power grid model and possible application examples like algorithms in grid analysis, operation and dynamic equipment modelling.

Proceedings of the 2008 CIGRE Canada conference on power systems : technology and innovation for the Canadian power grids of the future

International Nuclear Information System (INIS)

2008-01-01

The Conseil International des Grands Reseaux Electriques (CIGRE) promotes technical, economic and environmental developments in electricity transmission and generation. CIGRE Canada is one of 53 national committees of CIGRE. This conference showcased Canadian contributions to the electric power industry and how technology and innovation in the future will influence North American power grids. It provided a forum to discuss technological developments in the electric power industry and present products and services for electrical power systems. Issues concerning the interconnection of non traditional energy sources to the power systems were also discussed along with recent research initiatives related to renewable energy source development. The sessions of the conference were entitled: wind reliability and forecasting; substation automation and communication; human resources and long range planning; power system protection and control; distributed generation; electric vehicles and renewable energy; HVDC and facts; modeling and simulation; markets; overhead transmission lines; and new sensor and de-icing technologies and data management systems. All 68 presentations featured at this conference have been catalogued separately for inclusion in this database. refs., tabs., figs

Advanced Grid Support Functionality Testing for Florida Power and Light

Energy Technology Data Exchange (ETDEWEB)

Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Martin, Gregory [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hurtt, James [Florida Power and Light, Juno Beach, FL (United States)

2017-03-21

This report describes the results of laboratory testing of advanced photovoltaic (PV) inverter testing undertaken by the National Renewable Energy Laboratory (NREL) on behalf of the Florida Power and Light Company (FPL). FPL recently commissioned a 1.1 MW-AC PV installation on a solar carport at the Daytona International Speedway in Daytona Beach, Florida. In addition to providing a source of clean energy production, the site serves as a live test bed with 36 different PV inverters from eight different manufacturers. Each inverter type has varied support for advanced grid support functions (GSFs) that are becoming increasingly commonplace, and are being required through revised interconnection standards such as UL1741, IEEE1547, and California (CA) Rule 21. FPL is interested in evaluating the trade-offs between different GSFs, their compliance to emerging standards, and their effects on efficiency and reliability. NREL has provided a controlled laboratory environment to undertake such a study. This work covered nine different classes of tests to compare inverter capabilities and performance for four different inverters that were selected by FPL. The test inverters were all three-phase models rated between 24-36 kW, and containing multiple PV input power point trackers. Advanced grid support functions were tested for functional behavior, and included fixed power factor operation, voltage-ride through, frequency ride-through, volt-var control, and frequency-Watt control. Response to abnormal grid conditions with GSFs enabled was studied through anti-islanding, fault, and load rejection overvoltage tests. Finally, efficiency was evaluated across a range of operating conditions that included power factor, output power, and input voltage variations. Test procedures were derived from requirements of a draft revision of UL741, CA Rule 21, and/or previous studies at NREL. This reports summarizes the results of each test case, providing a comparative performance analysis

Congestion management in a smart grid via shadow prices

DEFF Research Database (Denmark)

Biegel, Benjamin; Andersen, Palle; Stoustrup, Jakob

2012-01-01

We consider a distribution grid interconnecting a number of consumers with flexible power consumption. Each consumer is under the jurisdiction of exactly one balancing responsible party (BRP), who buys energy at a day-ahead electricity market on behalf of the consumer. We illustrate how BRPs can...

Interconnectivity: Benefits and Challenges

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-09-15

Access to affordable and reliable electricity supplies is a basic prerequisite for economic and social development, prosperity, health, education and all other aspects of modern society. Electricity can be generated both near and far from the consumption areas as transmission lines, grid interconnections and distribution systems can transport it to the final consumer. In the vast majority of countries, the electricity sector used to be owned and run by the state. The wave of privatisation and market introduction in a number of countries and regions which started in the late 1980's has in many cases involved unbundling of generation from transmission and distribution (T and D). This has nearly everywhere exposed transmission bottlenecks limiting the development of well-functioning markets. Transmission on average accounts for about 10-15% of total final kWh cost paid by the end-user but it is becoming a key issue for effective operation of liberalised markets and for their further development. An integrated and adequate transmission infrastructure is of utmost importance for ensuring the delivery of the most competitively priced electricity, including externalities, to customers, both near and far from the power generating facilities. In this report, the role of interconnectivity in the development of energy systems is examined with the associated socio-economic, environmental, financial and regulatory aspects that must be taken into account for successful interconnection projects.

Optimal Operation Method of Smart House by Controllable Loads based on Smart Grid Topology

Science.gov (United States)

Yoza, Akihiro; Uchida, Kosuke; Yona, Atsushi; Senju, Tomonobu

2013-08-01

From the perspective of global warming suppression and depletion of energy resources, renewable energy such as wind generation (WG) and photovoltaic generation (PV) are getting attention in distribution systems. Additionally, all electrification apartment house or residence such as DC smart house have increased in recent years. However, due to fluctuating power from renewable energy sources and loads, supply-demand balancing fluctuations of power system become problematic. Therefore, "smart grid" has become very popular in the worldwide. This article presents a methodology for optimal operation of a smart grid to minimize the interconnection point power flow fluctuations. To achieve the proposed optimal operation, we use distributed controllable loads such as battery and heat pump. By minimizing the interconnection point power flow fluctuations, it is possible to reduce the maximum electric power consumption and the electric cost. This system consists of photovoltaics generator, heat pump, battery, solar collector, and load. In order to verify the effectiveness of the proposed system, MATLAB is used in simulations.

Analysis of the influences of grid-connected PV power system on distribution grids

Directory of Open Access Journals (Sweden)

Dumitru Popandron

2013-12-01

Full Text Available This paper presents the analysis of producing an electric power of 2.8 MW using a solar photovoltaic plant. The PV will be grid connected to the distribution network. The study is focused on the influences of connecting to the grid of a photovoltaic system, using modern software for analysis, modeling and simulation in power systems.

Limitation of fusion power plant installation on future power grids under the effect of renewable and nuclear power sources

Energy Technology Data Exchange (ETDEWEB)

Takeda, Shutaro, E-mail: takeda.shutarou.55r@st.kyoto-u.ac.jp [Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Kyoto (Japan); Sakurai, Shigeki [Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Kyoto (Japan); Yamamoto, Yasushi [Faculty of Engineering Science, Kansai University, Suita, Osaka (Japan); Kasada, Ryuta; Konishi, Satoshi [Institute of Advanced Energy, Kyoto University, Uji, Kyoto (Japan)

2016-11-01

Graphical abstract: - Highlights: • Future power grids would be unstable due to renewable and nuclear power sources. • Output interruptions of fusion plant would cause disturbances to future grids. • Simulation results suggested they would create limitations in fusion installation. • A novel diagram was presented to illustrate this suggested limitation. - Abstract: Future power grids would be unstable because of the larger share of renewable and nuclear power sources. This instability might bring some additional difficulties to fusion plant installation. Therefore, the authors carried out a quantitative feasibility study from the aspect of grid stability through simulation. Results showed that the more renewable and nuclear sources are linked to a grid, the greater disturbance the grid experiences upon a sudden output interruption of a fusion power plant, e.g. plasma disruption. The frequency deviations surpassed 0.2 Hz on some grids, suggesting potential limitations of fusion plant installation on future grids. To clearly show the suggested limitations of fusion plant installations, a novel diagram was presented.

Construction and application research of Three-dimensional digital power grid in Southwest China

Science.gov (United States)

Zhou, Yang; Zhou, Hong; You, Chuan; Jiang, Li; Xin, Weidong

2018-01-01

With the rapid development of Three-dimensional (3D) digital design technology in the field of power grid construction, the data foundation and technical means of 3D digital power grid construction approaches perfection. 3D digital power grid has gradually developed into an important part of power grid construction and management. In view of the complicated geological conditions in Southwest China and the difficulty in power grid construction and management, this paper is based on the data assets of Southwest power grid, and it aims at establishing a 3D digital power grid in Southwest China to provide effective support for power grid construction and operation management. This paper discusses the data architecture, technical architecture and system design and implementation process of the 3D digital power grid construction through teasing the key technology of 3D digital power grid. The application of power grid data assets management, transmission line corridor planning, geological hazards risk assessment, environmental impact assessment in 3D digital power grid are also discussed and analysed.

Grid tied PV/battery system architecture and power management for fast electric vehicle charging

Science.gov (United States)

Badawy, Mohamed O.

The prospective spread of Electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) arises the need for fast charging rates. Higher charging rates requirements lead to high power demands, which cant be always supported by the grid. Thus, the use of on-site sources alongside the electrical grid for EVs charging is a rising area of interest. In this dissertation, a photovoltaic (PV) source is used to support the high power EVs charging. However, the PV output power has an intermittent nature that is dependable on the weather conditions. Thus, battery storage are combined with the PV in a grid tied system, providing a steady source for on-site EVs use in a renewable energy based fast charging station. Verily, renewable energy based fast charging stations should be cost effective, efficient, and reliable to increase the penetration of EVs in the automotive market. Thus, this Dissertation proposes a novel power flow management topology that aims on decreasing the running cost along with innovative hardware solutions and control structures for the developed architecture. The developed power flow management topology operates the hybrid system at the minimum operating cost while extending the battery lifetime. An optimization problem is formulated and two stages of optimization, i.e online and offline stages, are adopted to optimize the batteries state of charge (SOC) scheduling and continuously compensate for the forecasting errors. The proposed power flow management topology is validated and tested with two metering systems, i.e unified and dual metering systems. The results suggested that minimal power flow is anticipated from the battery storage to the grid in the dual metering system. Thus, the power electronic interfacing system is designed accordingly. Interconnecting bi-directional DC/DC converters are analyzed, and a cascaded buck boost (CBB) converter is chosen and tested under 80 kW power flow rates. The need to perform power factor correction (PFC) on

Accurate calibration of steam turbine speed control system and its influence on primary regulation at electric grid

Energy Technology Data Exchange (ETDEWEB)

Irrazabal Bohorquez, Washington Orlando; Barbosa, Joao Roberto [Technological Institute of Aeronautics (ITA/CTA), Sao Jose dos Campos, SP (Brazil). Center for Reference on Gas Turbine and Energy], E-mail: barbosa@ita.br

2010-07-01

In an interconnected electric system there are two very important parameters: the field voltage and the frequency system. The frequency system is very important for the primary regulation of the electric grid. Each turbomachine actuating as generator interconnected to the grid has an automatic speed regulator to keep the rotational speed and mechanical power of the prime machine operating at the set conditions and stable frequency. The electric grid is a dynamical system and in every moment the power units are exposed to several types of disturbances, which cause unbalance of the mechanical power developed by prime machine and the consumed electric power at the grid. The steam turbine speed control system controls the turbine speed to support the electric grid primary frequency at the same time it controls the frequency of the prime machine. Using a mathematical model for the speed control system, the transfer functions were calculated, as well as the proportionality constants of each element of the steam turbine automatic speed regulator. Among other parameters, the droop characteristic of steam turbine and the dynamic characteristics of the automatic speed regulator elements were calculated. Another important result was the determination of the behavior of the speed control when disturbances occur with the improvement of the calibration precision of the control system. (author)

A Vision of China-Arab Interconnection Transmission Network Planning with UHVDC Technology

Science.gov (United States)

Wu, Dan; Liu, Yujun; Yin, Hongyuan; Xu, Qingshan; Xu, Xiaohui; Ding, Maosheng

2017-05-01

Developments in ultra-high-voltage (UHV) power systems and clean energy technologies are paving the way towards unprecedented energy market globalization. In accordance with the international community’s enthusiasm for building up the Global Energy Internet, this paper focuses on the feasibility of transmitting large-size electricity from northwest China to Arab world through a long-distance transnational power interconnection. The complete investigations on the grids of both the sending-end and receiving-end is firstly presented. Then system configuration of the transmission scheme and corridor route planning is proposed with UHVDC technology. Based on transmission costs’ investigation about similar transmission projects worldwide, the costs of the proposed transmission scheme are estimated through adjustment factors which represent differences in latitude, topography and economy. The proposed China-Arab transmission line sheds light on the prospects of power cooperation and resource sharing between China and Arab states, and appeals for more emphasis on green energy concentrated power interconnections from a global perspective.

Power Line Communications for Smart Grid Applications

Directory of Open Access Journals (Sweden)

Lars Torsten Berger

2013-01-01

Full Text Available Power line communication, that is, using the electricity infrastructure for data transmission, is experiencing a renaissance in the context of Smart Grid. Smart Grid objectives include the integration of intermittent renewable energy sources into the electricity supply chain, securing reliable electricity delivery, and using the existing electrical infrastructure more efficiently. This paper surveys power line communications (PLCs in the context of Smart Grid. The specifications G3-PLC, PRIME, HomePlug Green PHY, and HomePlug AV2, and the standards IEEE 1901/1901.2 and ITU-T G.hn/G.hnem are discussed.

Use of thermoelectric generators for improve power dependability over grid power

Energy Technology Data Exchange (ETDEWEB)

Archer, Jack [Global Thermoelectric, Calgary (Canada)

2005-07-01

A natural gas transportation company was experiencing extensive pipeline corrosion on some sections of their pipeline protected by impressed current using grid power and rectifiers. After determining that grid power was being interrupted on the affected sections, the gas transporter began looking for a more dependable power supply and chose thermoelectric generators. Since installing thermoelectric generators in 2002, the pipeline potentials have stabilized and transporter was able to experience 100% operational time on affected sections. (author)

Smart signal processing for an evolving electric grid

Science.gov (United States)

Silva, Leandro Rodrigues Manso; Duque, Calos Augusto; Ribeiro, Paulo F.

2015-12-01

Electric grids are interconnected complex systems consisting of generation, transmission, distribution, and active loads, recently called prosumers as they produce and consume electric energy. Additionally, these encompass a vast array of equipment such as machines, power transformers, capacitor banks, power electronic devices, motors, etc. that are continuously evolving in their demand characteristics. Given these conditions, signal processing is becoming an essential assessment tool to enable the engineer and researcher to understand, plan, design, and operate the complex and smart electronic grid of the future. This paper focuses on recent developments associated with signal processing applied to power system analysis in terms of characterization and diagnostics. The following techniques are reviewed and their characteristics and applications discussed: active power system monitoring, sparse representation of power system signal, real-time resampling, and time-frequency (i.e., wavelets) applied to power fluctuations.

Microcoil Spring Interconnects for Ceramic Grid Array Integrated Circuits

Science.gov (United States)

Strickland, S. M.; Hester, J. D.; Gowan, A. K.; Montgomery, R. K.; Geist, D. L.; Blanche, J. F.; McGuire, G. D.; Nash, T. S.

2011-01-01

As integrated circuit miniaturization trends continue, they drive the need for smaller higher input/output (I/O) packages. Hermetically sealed ceramic area array parts are the package of choice by the space community for high reliability space flight electronic hardware. Unfortunately, the coefficient of thermal expansion mismatch between the ceramic area array package and the epoxy glass printed wiring board limits the life of the interconnecting solder joint. This work presents the results of an investigation by Marshall Space Flight Center into a method to increase the life of this second level interconnection by the use of compliant microcoil springs. The design of the spring and its attachment process are presented along with thermal cycling results of microcoil springs (MCS) compared with state-of-the-art ball and column interconnections. Vibration testing has been conducted on MCS and high lead column parts. Radio frequency simulation and measurements have been made and the MCS has been modeled and a stress analysis performed. Thermal cycling and vibration testing have shown MCS interconnects to be significantly more reliable than solder columns. Also, MCS interconnects are less prone to handling damage than solder columns. Future work that includes shock testing, incorporation into a digital signal processor board, and process evaluation of expansion from a 400 I/O device to a device with over 1,100 I/O is identified.

Wind power within European grid codes: Evolution, status and outlook

DEFF Research Database (Denmark)

Vrana, Til Kristian; Flynn, Damian; Gomez-Lazaro, Emilio

2018-01-01

Grid codes are technical specifications that define the requirements for any facility connected to electricity grids. Wind power plants are increasingly facing system stability support requirements similar to conventional power stations, which is to some extent unavoidable, as the share of wind...... power in the generation mix is growing. The adaptation process of grid codes for wind power plants is not yet complete, and grid codes are expected to evolve further in the future. ENTSO-E is the umbrella organization for European TSOs, seen by many as a leader in terms of requirements sophistication...... is largely based on the definitions and provisions set out by ENTSO-E. The main European grid code requirements are outlined here, including also HVDC connections and DC-connected power park modules. The focus is on requirements that are considered particularly relevant for large wind power plants...

Method for controlling power flow between an electrochemical cell and a power grid

International Nuclear Information System (INIS)

Coleman, A. K.

1981-01-01

A method is disclosed for controlling a force-commutated inverter coupled between an electrochemical cell and a power grid for adjusting the magnitude and direction of the electrical energy flowing therebetween. Both the real power component and the reactive power component of ac electrical energy flow can be independently VARied through the switching waveform presented to the intermediately coupled inverter. A VAR error signal is derived from a comparison of a var command signal with a signal proportional to the actual reactive power circulating between the inverter and the power grid. This signal is presented to a voltage controller which essentially varies only the effective magnitude of the fundamental voltage waveform out of the inverter , thereby leaving the real power component substantially unaffected. In a similar manner, a power error signal is derived by a comparison of a power command signal with a signal proportional to the actual real power flowing between the electrochemical cell and the power grid. This signal is presented to a phase controller which varies only the phase of the fundamental component of the voltage waveform out of the inverter relative to that of the power grid and changes only the real power in proportion thereto, thus leaving the reactive power component substantially unaffected

Integration of permanent magnet synchronous generator wind turbines into power grid

Science.gov (United States)

Abedini, Asghar

The world is seeing an ever-increasing demand for electrical energy. The future growth of electrical power generation needs to be a mix of technologies including fossil fuels, hydro, nuclear, wind, and solar. The federal and state energy agencies have taken several proactive steps to increase the share of renewable energy in the total generated electrical power. In 2005, 11.1% of the total 1060 GW electricity generation capacity was from Renewable Energy Sources (RES) in the US. The power capacity portfolio included 9.2% from hydroelectric, 0.87% from wind, and 0.7% from biomass. Other renewable power capacity included 2.8 GW of geothermal, 0.4 GW of solar thermal, and 0.2 GW of solar PV. Although the share of renewable energy sources is small compared with the total power capacity, they are experiencing a high and steady growth. The US is leading the world in wind energy growth with a 27% increase in 2006 and a projected 26% increase in 2007, according to the American Wind Energy Association (AWEA). The US Department of Energy benchmarked a goal to meet 5% of the nation's energy need by launching the Wind Powering America (WPA) program. Although renewable energy sources have many benefits, their utilization in the electrical grid does not come without cost. The higher penetration of RES has introduced many technical and non-technical challenges, including power quality, reliability, safety and protection, load management, grid interconnections and control, new regulations, and grid operation economics. RES such as wind and PV are also intermittent in nature. The energy from these sources is available as long as there is wind or sunlight. However, these are energies that are abundant in the world and the power generated from these sources is pollution free. Due to high price of foundation of wind farms, employing variable speed wind turbines to maximize the extracted energy from blowing wind is more beneficial. On the other hand, since wind power is intermittent

A GA-fuzzy automatic generation controller for interconnected power system

CSIR Research Space (South Africa)

Boesack, CD

2011-10-01

Full Text Available This paper presents a GA-Fuzzy Automatic Generation Controller for large interconnected power systems. The design of Fuzzy Logic Controllers by means of expert knowledge have typically been the traditional design norm, however, this may not yield...

Regression and kriging analysis for grid power factor estimation

OpenAIRE

Rajesh Guntaka; Harley R. Myler

2014-01-01

The measurement of power factor (PF) in electrical utility grids is a mainstay of load balancing and is also a critical element of transmission and distribution efficiency. The measurement of PF dates back to the earliest periods of electrical power distribution to public grids. In the wide-area distribution grid, measurement of current waveforms is trivial and may be accomplished at any point in the grid using a current tap transformer. However, voltage measurement requires reference to grou...

Grid-Connected Photovoltaic System with Active Power Filtering Functionality

Directory of Open Access Journals (Sweden)

Joaquín Vaquero

2018-01-01

Full Text Available Solar panels are an attractive and growing source of renewable energy in commercial and residential applications. Its use connected to the grid by means of a power converter results in a grid-connected photovoltaic system. In order to optimize this system, it is interesting to integrate several functionalities into the power converter, such as active power filtering and power factor correction. Nonlinear loads connected to the grid generate current harmonics, which deteriorates the mains power quality. Active power filters can compensate these current harmonics. A photovoltaic system with added harmonic compensation and power factor correction capabilities is proposed in this paper. A sliding mode controller is employed to control the power converter, implemented on the CompactRIO digital platform from National Instruments Corporation, allowing user friendly operation and easy tuning. The power system consists of two stages, a DC/DC boost converter and a single-phase inverter, and it is able to inject active power into the grid while compensating the current harmonics generated by nonlinear loads at the point of common coupling. The operation, design, simulation, and experimental results for the proposed system are discussed.

Grid-connected inverter for wind power generation system

Institute of Scientific and Technical Information of China (English)

YANG Yong; RUAN Yi; SHEN Huan-qing; TANG Yan-yan; YANG Ying

2009-01-01

In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation (SVPWM) is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on PI-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response.

Space weather and power grids: findings and outlook

Science.gov (United States)

Krausmann, Elisabeth; Andersson, Emmelie; Murtagh, William; Mitchison, Neil

2014-05-01

The impact of space weather on the power grid is a tangible and recurring threat with potentially serious consequences on society. Of particular concern is the long-distance high-voltage power grid, which is vulnerable to the effects of geomagnetic storms that can damage or destroy equipment or lead to grid collapse. In order to launch a dialogue on the topic and encourage authorities, regulators and operators in European countries and North America to learn from each other, the European Commission's Joint Research Centre, the Swedish Civil Contingencies Agency, and NOAA's Space Weather Prediction Centre, with the contribution of the UK Civil Contingencies Secretariat, jointly organised a workshop on the impact of extreme space weather on the power grid on 29-30 October 2013. Being structured into 6 sessions, the topics addressed were space-weather phenomena and the dynamics of their impact on the grid, experiences with prediction and now-casting in the USA and in Europe, risk assessment and preparedness, as well as policy implications arising from increased awareness of the space-weather hazard. The main workshop conclusions are: • There is increasing awareness of the risk of space-weather impact among power-grid operators and regulators and some countries consider it a priority risk to be addressed. • The predictability of space-weather phenomena is still limited and relies, in part, on data from ageing satellites. NOAA is working with NASA to launch the DSCOVR solar wind spacecraft, the replacement for the ACE satellite, in early 2015. • In some countries, models and tools for GIC prediction and grid impact assessment have been developed in collaboration with national power grids but equipment vulnerability models are scarce. • Some countries have successfully hardened their transmission grids to space-weather impact and sustained relatively little or no damage due to currents induced by past moderate space-weather events. • While there is preparedness

Power-electronic asset characteristics for HVDC-connected offshore grids

Energy Technology Data Exchange (ETDEWEB)

Heising, C.; Meyer, D.; Bartelt, R. [Avasition GmbH, Dortmund (Germany); Koochack Zadeh, M.; Lebioda, T.J.; Jung, J. [TenneT Offshore GmbH, Bayreuth (Germany)

2012-07-01

Analysing offshore wind-farm applications as well as other converter-dominated grids, two key differences can be identified compared to conventional configurations: No relevant short-circuit power is available and no inertia is directly coupled to the AC grid. Within this paper, power-electronic asset characteristics for HVDC-connected offshore grids are presented which apply new principles allowing for better dynamic operation in the weak grids introduced. The capability is demonstrated using simulation results of an AC-multi-terminal system. (orig.)

Market aspects of smart power grids development

Directory of Open Access Journals (Sweden)

Maciej Makowski

2012-03-01

Full Text Available Smart Grids herald a revolution in the power sector. The centralized and passive power grid model known for over a century is before our very eyes assuming a completely brand new shape: of an active and dynamic network with an increasingly relevant role of consumers – prosumers, who are offered brand new products and services. Such an active development is possible due to a number of factors, such as: 1. Synergy of ICT with power engineering – these disciplines are becoming an indispensable element of the modern power grid’s operation, 2. The European Union’s regulations in the area of reduction of CO2 emission and improved energy efficiency, as well as identification of Smart Grids as one of the optimum tools, 3. Growth, thanks to continuously increasing expenditures, public awareness of the purchase and rational use of energy. However, the Smart Grid development and ICT implementation in the power sector also carry a risk in the matter of setting up system and process links between the systems of concerned energy market players, which should be mitigated by development of technical standards, methods and principles of good cooperation between the concerned parties. Mitigation of the risk, and as a consequence, effective Smart Grids development will provide conditions for dynamic development of new roles and mechanisms on the energy market. Offering modern products and services to consumers and prosumers, and effective implementation on a national scale of demand management mechanisms will be a source of multidimensional benefits of a functional and financial nature, and will also have a positive impact on the National Lower Grid’s security.

The Effect of Phase-to-earth Faults on the Operating Conditions of a Separated 110 kV Grid Normally Operated with Effectively Earthed Neutral, and Temporarily Supplied from a Compensated 110 kV Grid

Directory of Open Access Journals (Sweden)

Wilhelm Rojewski

2015-06-01

Full Text Available The paper discusses the interoperability of the German compensated 110 kV grid and the Polish effectively earthed 110 kV grid. It is assumed that an area of one grid, separated from its power system, will be temporarily supplied from the other grid in its normal regime. Reference is made to the risks associated with phase-to-earth faults in grids so interconnected. Particular attention is paid to the working conditions of surge arresters and voltage transformers in the Polish 110 kV grid deprived of its neutral earthing when supplied from the German grid.

Controller design and stability analysis of grid connected DC microgrid

DEFF Research Database (Denmark)

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...

A Stationary Reference Frame Grid Synchronization System for Three-Phase Grid-Connected Power Converters Under Adverse Grid Conditions

DEFF Research Database (Denmark)

Rodríguez, P.; Luna, A.; Muñoz-Aguilar, R. S.

2012-01-01

synchronization method for three-phase three-wire networks, namely dual second-order generalized integrator (SOGI) frequency-locked loop. The method is based on two adaptive filters, implemented by using a SOGI on the stationary αβ reference frame, and it is able to perform an excellent estimation......Grid synchronization algorithms are of great importance in the control of grid-connected power converters, as fast and accurate detection of the grid voltage parameters is crucial in order to implement stable control strategies under generic grid conditions. This paper presents a new grid...

Grid-friendly wind power systems based on the synchronverter technology

International Nuclear Information System (INIS)

Zhong, Qing-Chang; Ma, Zhenyu; Ming, Wen-Long; Konstantopoulos, George C.

2015-01-01

Highlights: • A grid-friendly wind power system that uses the synchronverter technology is proposed. • Both the rotor-side and the grid-side converters act as synchronverters. • The complete generator–motor–generator system improves the performance under grid faults. • Real-time digital simulation results verify the effectiveness of the proposed method. - Abstract: Back-to-back PWM converters are becoming a realistic alternative to conventional converters in high-power wind power applications. In this paper, a control strategy based on the synchronverter technology is proposed for back-to-back PWM converters. Both converters are run as synchronverters, which are mathematically equivalent to the conventional synchronous generators. The rotor-side converter is responsible for maintaining the DC link voltage and the grid-side converter is responsible for the maximum power point tracking (MPPT). As the two converters are operated using the synchronverter technology, the formed wind power system becomes more friendly to the grid. Extensive real-time digital simulation results are presented to verify the effectiveness of the proposed method under normal operation and grid-fault scenarios

Monitoring, control and protection of interconnected power systems

CERN Document Server

Häger, Ulf; Voropai, Nikolai

2014-01-01

This book presents new tools and methods for monitoring, control and protection of large scale power systems, adapting Smart Grid technologies based on wide area data exchange in combination with modern measurement devices and advanced network controllers.

Wind and Solar on the Power Grid: Myths and Misperceptions, Greening the Grid (Spanish Version)

Energy Technology Data Exchange (ETDEWEB)

Authors: Denholm, Paul; Cochran, Jaquelin; Brancucci Martinez-Anido, Carlo

2016-04-01

This is the Spanish version of the 'Greening the Grid - Wind and Solar on the Power Grid: Myths and Misperceptions'. Wind and solar are inherently more variable and uncertain than the traditional dispatchable thermal and hydro generators that have historically provided a majority of grid-supplied electricity. The unique characteristics of variable renewable energy (VRE) resources have resulted in many misperceptions regarding their contribution to a low-cost and reliable power grid. Common areas of concern include: 1) The potential need for increased operating reserves, 2) The impact of variability and uncertainty on operating costs and pollutant emissions of thermal plants, and 3) The technical limits of VRE penetration rates to maintain grid stability and reliability. This fact sheet corrects misperceptions in these areas.

Delta Power Control Strategy for Multi-String Grid-Connected PV Inverters

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

With a still increasing penetration level of grid-connected PV systems, more advanced active power control functionalities have been introduced in certain grid regulations. A delta power constraint, where a portion of the active power from the PV panels is reserved during operation, is required...... for grid support (e.g., during frequency deviation). In this paper, a cost-effective solution to realize delta power control for grid-connected PV systems is presented, where the residential/commercial multi-string PV inverter configuration is adopted. This control strategy is a combination of Maximum...... for the entire PV system is achieved. Simulations and experiments have been performed on a 3-kW single-phase grid-connected PV system. The results have confirmed the effectiveness of the delta power control strategy, where the power reserve according to the delta power constraint is achieved under several...

Improving power grid transient stability by plug-in electric vehicles

International Nuclear Information System (INIS)

Gajduk, Andrej; Kocarev, Ljupco; Todorovski, Mirko; Kurths, Juergen

2014-01-01

Plug-in electric vehicles (PEVs) can serve in discharge mode as distributed energy and power resources operating as vehicle-to-grid (V2G) devices and in charge mode as loads or grid-to-vehicle devices. It has been documented that PEVs serving as V2G systems can offer possible backup for renewable power sources, can provide reactive power support, active power regulation, load balancing, peak load shaving, can reduce utility operating costs and can generate revenue. Here we show that PEVs can even improve power grid transient stability, that is, stability when the power grid is subjected to large disturbances, including bus faults, generator and branch tripping, and sudden large load changes. A control strategy that regulates the power output of a fleet of PEVs based on the speed of generator turbines is proposed and tested on the New England 10-unit 39-bus power system. By regulating the power output of the PEVs we show that (1) speed and voltage fluctuations resulting from large disturbances can be significantly reduced up to five times, and (2) the critical clearing time can be extended by 20–40%. Overall, the PEVs control strategy makes the power grid more robust. (paper)

Optimal system sizing in grid-connected photovoltaic applications

Science.gov (United States)

Simoens, H. M.; Baert, D. H.; de Mey, G.

A costs/benefits analysis for optimizing the combination of photovoltaic (PV) panels, batteries and an inverter for grid interconnected systems at a 500 W/day Belgian residence is presented. It is assumed that some power purchases from the grid will always be necessary, and that excess PV power can be fed into the grid. A minimal value for the cost divided by the performance is defined for economic optimization. Shortages and excesses are calculated for PV panels of 0.5-10 kWp output, with consideration given to the advantages of a battery back-up. The minimal economic value is found to increase with the magnitude of PV output, and an inverter should never be rated at more than half the array maximum output. A maximum panel size for the Belgian residence is projected to be 6 kWp.

The Most Economical Mode of Power Supply for Remote and Less Developed Areas in China: Power Grid Extension or Micro-Grid?

Directory of Open Access Journals (Sweden)

Sen Guo

2017-05-01

Full Text Available There are still residents without access to electricity in some remote and less developed areas of China, which lead to low living standards and hinder sustainable development for these residents. In order to achieve the strategic targets of solving China’s energy poverty, realizing basic energy service equalization, and comprehensively building up a moderately prosperous society, several policies have been successively promulgated in recent years, which aim to solve the electricity access issue for residents living in remote and less developed areas. It is of great importance to determine the most economical mode of power supply in remote and less developed areas, which directly affects the economic efficiency of public investment projects. Therefore, this paper focuses on how to select the most economical power supply mode for rural electrification in China. Firstly, the primary modes to supply electricity for residents living in the remote and less developed areas are discussed, which include power grid extension mode and micro-grid mode. Secondly, based on the levelized cost of electricity (LCOE technique, the life cycle economic cost accounting model for different power supply modes are built. Finally, taking a minority nationality village in Yunnan province as an example, the empirical analysis is performed, and the LCOEs of various possible modes for rural electrification are accounted. The results show that the photovoltaic (PV-based independent micro-grid system is the most economical due to the minimum LCOE, namely 0.658 RMB/kWh. However, other power supply modes have much higher LCOEs. The LCOEs of power grid extension model, wind-based independent micro-grid system and biomass-based independent micro-grid system are 1.078 RMB/kWh, 0.704 RMB/kWh and 0.885 RMB/kWh, respectively. The proposed approach is effective and practical, which can provide reference for rural electrification in China.

Distributed Optimization of Sustainable Power Dispatch and Flexible Consumer Loads for Resilient Power Grid Operations

Science.gov (United States)

Srikantha, Pirathayini

Today's electric grid is rapidly evolving to provision for heterogeneous system components (e.g. intermittent generation, electric vehicles, storage devices, etc.) while catering to diverse consumer power demand patterns. In order to accommodate this changing landscape, the widespread integration of cyber communication with physical components can be witnessed in all tenets of the modern power grid. This ubiquitous connectivity provides an elevated level of awareness and decision-making ability to system operators. Moreover, devices that were typically passive in the traditional grid are now `smarter' as these can respond to remote signals, learn about local conditions and even make their own actuation decisions if necessary. These advantages can be leveraged to reap unprecedented long-term benefits that include sustainable, efficient and economical power grid operations. Furthermore, challenges introduced by emerging trends in the grid such as high penetration of distributed energy sources, rising power demands, deregulations and cyber-security concerns due to vulnerabilities in standard communication protocols can be overcome by tapping onto the active nature of modern power grid components. In this thesis, distributed constructs in optimization and game theory are utilized to design the seamless real-time integration of a large number of heterogeneous power components such as distributed energy sources with highly fluctuating generation capacities and flexible power consumers with varying demand patterns to achieve optimal operations across multiple levels of hierarchy in the power grid. Specifically, advanced data acquisition, cloud analytics (such as prediction), control and storage systems are leveraged to promote sustainable and economical grid operations while ensuring that physical network, generation and consumer comfort requirements are met. Moreover, privacy and security considerations are incorporated into the core of the proposed designs and these

Grid converters for photovoltaic and wind power systems

CERN Document Server

Teodorescu, Remus; Rodríguez, Pedro

2011-01-01

"Grid Converters for Photovoltaic and Wind Power Systems provides a comprehensive description of the control of grid converters for photovoltaic and wind power systems. The authors present a range of control methods for meeting the latest application, power quality and power conversion requirements and standards, as well as looking towards potential future control functions. Practical examples, exercises, and an accompanying website with simulation models using Matlab and Simulink environments, and PSIM software make this text a pragmatic resource for electrical engineers as well as students taking related courses"--

Grid Code Requirements for Wind Power Integration

DEFF Research Database (Denmark)

Wu, Qiuwei

2018-01-01

This chapter reviews the grid code requirements for integration of wind power plants (WPPs). The grid codes reviewed are from the UK, Ireland, Germany, Denmark, Spain, Sweden, the USA, and Canada. Transmission system operators (TSOs) around the world have specified requirements for WPPs under...

Exact Power Constraints in Smart Grid Control

DEFF Research Database (Denmark)

Trangbæk, K; Petersen, Mette Højgaard; Bendtsen, Jan Dimon

2011-01-01

This paper deals with hierarchical model predictive control (MPC) of smart grid systems. The objective is to accommodate load variations on the grid, arising from varying consumption and natural variations in the power production e.g. from wind turbines. This balancing between supply and demand...

An adaptive Phase-Locked Loop algorithm for faster fault ride through performance of interconnected renewable energy sources

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

2013-01-01

Interconnected renewable energy sources require fast and accurate fault ride through operation in order to support the power grid when faults occur. This paper proposes an adaptive Phase-Locked Loop (adaptive dαβPLL) algorithm, which can be used for a faster and more accurate response of the grid...... side converter control of a renewable energy source, especially under fault ride through operation. The adaptive dαβPLL is based on modifying the control parameters of the dαβPLL according to the type and voltage characteristic of the grid fault with the purpose of accelerating the performance...

Vehicle to Grid Demonstration Project

Energy Technology Data Exchange (ETDEWEB)

Willett Kempton; Meryl Gardner; Michael Hidrue; Fouad Kamilev; Sachin Kamboj; Jon Lilley; Rodney McGee; George Parsons; Nat Pearre; Keith Trnka

2010-12-31

This report summarizes the activities and accomplishments of a two-year DOE-funded project on Grid-Integrated Vehicles (GIV) with vehicle to grid power (V2G). The project included several research and development components: an analysis of US driving patterns; an analysis of the market for EVs and V2G-capable EVs; development and testing of GIV components (in-car and in-EVSE); interconnect law and policy; and development and filing of patents. In addition, development activities included GIV manufacturing and licensing of technologies developed under this grant. Also, five vehicles were built and deployed, four for the fleet of the State of Delaware, plus one for the University of Delaware fleet.

The footprint of atmospheric turbulence in power grid frequency measurements

Science.gov (United States)

Haehne, H.; Schottler, J.; Waechter, M.; Peinke, J.; Kamps, O.

2018-02-01

Fluctuating wind energy makes a stable grid operation challenging. Due to the direct contact with atmospheric turbulence, intermittent short-term variations in the wind speed are converted to power fluctuations that cause transient imbalances in the grid. We investigate the impact of wind energy feed-in on short-term fluctuations in the frequency of the public power grid, which we have measured in our local distribution grid. By conditioning on wind power production data, provided by the ENTSO-E transparency platform, we demonstrate that wind energy feed-in has a measurable effect on frequency increment statistics for short time scales (renewable generation.

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

Directory of Open Access Journals (Sweden)

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.

Wind power plant in grid operation

International Nuclear Information System (INIS)

Heier, S.

1993-01-01

There are new prospects for electrical energy supply in coastal regions and on islands if one succeeds in integrating the available wind energy, dependent on the weather, into existing and to be developed supply structures. Apart from the supply of energy, effects on the grid and on the electrical consumer are gaining in importance. For wind power plants, the operating behaviour is appreciably determined by the electro-technical concept. The mechanical/electrical energy conversion with the corresponding grid connection and plant control play an important part here. Results of measurements and computer simulation make the differences in the behaviour of wind power plants clear. (orig.) [de

Sensor Transmission Power Schedule for Smart Grids

Science.gov (United States)

Gao, C.; Huang, Y. H.; Li, J.; Liu, X. D.

2017-11-01

Smart grid has attracted much attention by the requirement of new generation renewable energy. Nowadays, the real-time state estimation, with the help of phasor measurement unit, plays an important role to keep smart grid stable and efficient. However, the limitation of the communication channel is not considered by related work. Considering the familiar limited on-board batteries wireless sensor in smart grid, transmission power schedule is designed in this paper, which minimizes energy consumption with proper EKF filtering performance requirement constrain. Based on the event-triggered estimation theory, the filtering algorithm is also provided to utilize the information contained in the power schedule. Finally, its feasibility and performance is demonstrated using the standard IEEE 39-bus system with phasor measurement units (PMUs).

An Adaptive Tuning Mechanism for Phase-Locked Loop Algorithms for Faster Time Performance of Interconnected Renewable Energy Sources

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

2015-01-01

Interconnected renewable energy sources (RES) require fast and accurate fault ride through (FRT) operation, in order to support the power grid, when faults occur. This paper proposes an adaptive phase-locked loop (adaptive dαβPLL) algorithm, which can be used for a faster and more accurate response...

Analysis of a power grid using a Kuramoto-like model

DEFF Research Database (Denmark)

Filatrella, G.; Nielsen, Arne Hejde; Pedersen, Niels Falsig

2008-01-01

We show that there is a link between the Kuramoto paradigm and another system of synchronized oscillators, namely an electrical power distribution grid of generators and consumers. The purpose of this work is to show both the formal analogy and some practical consequences. The mapping can be made...... quantitative, and under some necessary approximations a class of Kuramoto-like models, those with bimodal distribution of the frequencies, is most appropriate for the power-grid. In fact in the power-grid there are two kinds of oscillators: the “sources" delivering power to the “consumers"....

Regression and kriging analysis for grid power factor estimation

Directory of Open Access Journals (Sweden)

Rajesh Guntaka

2014-12-01

Full Text Available The measurement of power factor (PF in electrical utility grids is a mainstay of load balancing and is also a critical element of transmission and distribution efficiency. The measurement of PF dates back to the earliest periods of electrical power distribution to public grids. In the wide-area distribution grid, measurement of current waveforms is trivial and may be accomplished at any point in the grid using a current tap transformer. However, voltage measurement requires reference to ground and so is more problematic and measurements are normally constrained to points that have ready and easy access to a ground source. We present two mathematical analysis methods based on kriging and linear least square estimation (LLSE (regression to derive PF at nodes with unknown voltages that are within a perimeter of sample nodes with ground reference across a selected power grid. Our results indicate an error average of 1.884% that is within acceptable tolerances for PF measurements that are used in load balancing tasks.

Power Grid Construction Project Portfolio Optimization Based on Bi-level programming model

Science.gov (United States)

Zhao, Erdong; Li, Shangqi

2017-08-01

As the main body of power grid operation, county-level power supply enterprises undertake an important emission to guarantee the security of power grid operation and safeguard social power using order. The optimization of grid construction projects has been a key issue of power supply capacity and service level of grid enterprises. According to the actual situation of power grid construction project optimization of county-level power enterprises, on the basis of qualitative analysis of the projects, this paper builds a Bi-level programming model based on quantitative analysis. The upper layer of the model is the target restriction of the optimal portfolio; the lower layer of the model is enterprises’ financial restrictions on the size of the enterprise project portfolio. Finally, using a real example to illustrate operation proceeding and the optimization result of the model. Through qualitative analysis and quantitative analysis, the bi-level programming model improves the accuracy and normative standardization of power grid enterprises projects.

Overview of Recent Grid Codes for PV Power Integration

DEFF Research Database (Denmark)

Craciun, Bogdan-Ionut; Kerekes, Tamas; Sera, Dezso

2012-01-01

The challenge to bring down the cost of produced photovoltaic (PV) power had a major impact on the PV market and in consequence the grid operators experienced higher and higher PV power penetration. The growing share of this decentralized generation plants started to affect the grid stability...

Transient stability studies on industrial power systems interconnected to the transmission grid; Estudios de estabilidad transitoria en sistemas electricos industriales con generacion propia interconectaos con el sistema de transmision

Energy Technology Data Exchange (ETDEWEB)

Calderon Guizar, J.G. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: jgc@iie.org.mx

2010-10-15

Aiming to ensure continuity in the electrical supply to critical processes, the electrical systems of large industrial plants, i.e. gas, and petrochemical industries usually posses local generation. Should the local generation be enough to satisfy the demand of the plant, then the interconnection with the public grid is commonly used as an important support for emergency conditions. This paper is concerned with the dynamical performance of two interconnected industrial power systems tied to the transmission system. Simulation results indicate that the frequency performance of one of the industrial plants, after the transients caused by the loss of the tie with the transmission system have died out, is greatly improved if both industrial plants remain connected after the disturbance. [Spanish] La continuidad en el suministro de energia electrica a procesos criticos de grandes complejos industriales, tales como plantas petroquimicas, procesadoras de gas, etc., es un aspecto de fundamental importancia para garantizar una operacion adecuada de este tipo de complejos. Con el proposito de mejorar la confiabilidad en el suministro de energia a los procesos criticos, los sistemas electricos de estos complejos industriales, generalmente cuentan con generacion propia. Si la capacidad de generacion instalada en los sistemas industriales es suficiente para satisfacer el total de la carga del complejo, la interconexion con el sistema de transmision es utilizada principalmente como respaldo durante condiciones de emergencia. En este articulo se analiza el comportamiento dinamico de dos sistemas industriales con generacion propia, disenados para operar en forma aislada, interconectados entre si, a traves de un enlace de 115 kV y con el sistema de transmision. Los resultados obtenidos indican que el comportamiento de la frecuencia en estado estable en uno de los complejos, posterior a la perdida del enlace con el sistema de transmision, mejora de manera considerable cuando estos

Evolutions of the power grid: vector of sustainable development

International Nuclear Information System (INIS)

Croguennoc, Alain; Dalle, Bernard; Archambault, R.; Bony, P.E.; Bouneau, C.; Bourguignon, B.; Bouvier, D.; Beltran, A.; Chauvancy, A.; Chevassus-au-Louis, B.; Citi, S.; Claverie, B.; Colomb, B.; Dallet, M.; Deveaux, L.; Dubus, D.; Fresnedo, S.; Herreros, J.; Herz, O.; Isoard, J.; Jaussaud, E.; Laffaye, H.; Laroche, J.P.; Lasserre, D.; Lebas, N.; Lebranchu, D.; Leclerc, F.; Lemoine, D.; Leydier, C.; Malique, F.; Mazoyer, F.; Meudic, M.A.; Nguefeu, S.; Pajot, S.; Pilate, J.M.; Real, G.; Rosso, F.; Waeraas de Saint Martin, G.; Schwartzmann, S.; Serres, E.

2011-01-01

The abatement of energy consumption and the mass production of renewable energy are the main actions implemented to meet the climate challenge. In this context, the share of electric power in the final consumption is continuously growing up. Adapting the power transportation grid is necessary if we want to take up the challenge of the new paradigm 'new power generation sites, fatal and intermittent energy'. If this grid is the symbol of a modern and well-equipped France, it is also the revealer of our society antagonisms: change without disruption, progress without sacrifice of heritage and natural landscapes. Industries and grid operators will have to show some innovation and anticipation if they want this deep change to be a success. The French power grid has permitted the regional development in the past and will allow to take up the climate challenge in the future. Its inevitable position in the success of past transformations makes it an essential vector of sustainable development. (J.S.)

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

Science.gov (United States)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-03-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

An AC/AC Direct Power Conversion Topology Having Multiple Power Grid Connections with Adjustable Loading

DEFF Research Database (Denmark)

Klumpner, Christian; Blaabjerg, Frede

2004-01-01

independent producers/consumers to connect to multiple distribution grids in order to optimise the electricity price, as this will vary during the day from one power distribution company to another one. It will be needed to have a load that can smoothly adjust the power consumed from each power grid in order......Normally, a power converter has one supply port to connect to the power grid and one or multiple output ports to connect to AC loads that require variable voltage and variable frequency. As the trend on the energy market is towards deregulation, new converter topologies are needed to allow...... to minimize the overall energy cost or in case of special applications, to improve the system redundancy. Also, having a generator that can simultaneously feed fractions of its power into multiple grids which are not coupled (different voltage, frequency, displacement angle) and continuously adjust...

Study of complete interconnect reliability for a GaAs MMIC power amplifier

Science.gov (United States)

Lin, Qian; Wu, Haifeng; Chen, Shan-ji; Jia, Guoqing; Jiang, Wei; Chen, Chao

2018-05-01

By combining the finite element analysis (FEA) and artificial neural network (ANN) technique, the complete prediction of interconnect reliability for a monolithic microwave integrated circuit (MMIC) power amplifier (PA) at the both of direct current (DC) and alternating current (AC) operation conditions is achieved effectively in this article. As a example, a MMIC PA is modelled to study the electromigration failure of interconnect. This is the first time to study the interconnect reliability for an MMIC PA at the conditions of DC and AC operation simultaneously. By training the data from FEA, a high accuracy ANN model for PA reliability is constructed. Then, basing on the reliability database which is obtained from the ANN model, it can give important guidance for improving the reliability design for IC.

Power Quality Improvement in a Cascaded Multilevel Inverter Interfaced Grid Connected System Using a Modified Inductive–Capacitive–Inductive Filter with Reduced Power Loss and Improved Harmonic Attenuation

Directory of Open Access Journals (Sweden)

Meenakshi Jayaraman

2017-11-01

Full Text Available Recently, multilevel inverters are more researched due to the advantages they offer over conventional voltage source inverters in grid connected applications. Passive filters are connected at the output of these inverters to produce sinusoidal waveforms with reduced harmonics and to satisfy grid interconnection standard requirements. This work proposes a new passive filter topology for a pulse width modulated five-level cascaded inverter interfaced grid connected system. The proposed passive filter inserts an additional resistance-capacitance branch in parallel to the filter capacitor of the traditional inductive–capacitive–inductive filter in addition to a resistance in series with it to reduce damping power loss. It can attenuate the switching frequency harmonic current components much better than the traditional filter while maintaining the same overall inductance, reduced capacitance and resistance values. The basic parameter design procedure and an approach to discover the parameters of the proposed filter is introduced. Further, a novel methodology using Particle Swarm Optimization (PSO is recommended to guarantee minimum damping loss while ensuring reduced peak during resonance. In addition, PSO algorithm is newly employed in this work to maximize harmonic attenuation in and around the switching frequency on the premise of allowable values of filter inductance and capacitance. A comparative discussion considering traditional passive filters and the proposed filter is presented and evaluated through experiments conducted on a 110 V, 1 kW five-level grid connected inverter. The modulation algorithm for the multilevel inverter is implemented using a SPARTAN 6-XC6SLX25 Field Programmable Gate Array (FPGA processor. The analysis shows that the proposed filter not only provides decreased damping power loss but also is capable of providing considerable harmonic ripple reduction in the high frequency band, improved output waveforms and lesser

Net load forecasting for high renewable energy penetration grids

International Nuclear Information System (INIS)

Kaur, Amanpreet; Nonnenmacher, Lukas; Coimbra, Carlos F.M.

2016-01-01

We discuss methods for net load forecasting and their significance for operation and management of power grids with high renewable energy penetration. Net load forecasting is an enabling technology for the integration of microgrid fleets with the macrogrid. Net load represents the load that is traded between the grids (microgrid and utility grid). It is important for resource allocation and electricity market participation at the point of common coupling between the interconnected grids. We compare two inherently different approaches: additive and integrated net load forecast models. The proposed methodologies are validated on a microgrid with 33% annual renewable energy (solar) penetration. A heuristics based solar forecasting technique is proposed, achieving skill of 24.20%. The integrated solar and load forecasting model outperforms the additive model by 10.69% and the uncertainty range for the additive model is larger than the integrated model by 2.2%. Thus, for grid applications an integrated forecast model is recommended. We find that the net load forecast errors and the solar forecasting errors are cointegrated with a common stochastic drift. This is useful for future planning and modeling because the solar energy time-series allows to infer important features of the net load time-series, such as expected variability and uncertainty. - Highlights: • Net load forecasting methods for grids with renewable energy generation are discussed. • Integrated solar and load forecasting outperforms the additive model by 10.69%. • Net load forecasting reduces the uncertainty between the interconnected grids.

Market partner orientation in power grid operation; Marktpartnerorientierung im Netzbetrieb

Energy Technology Data Exchange (ETDEWEB)

Weiss, Claudia; Gebhardt, Andreas [Buelow und Consorten GmbH, Hamburg (Germany)

2012-11-15

Customer orientation is often neglected in power grid operation. Power grid owners have natural monopolies and defined territories and so far had little reason to consider their customers' needs. This is changing with changed boundary conditions. In the competition for concessions and customers for non-regulated services, those grid owners will prevail in the long run wo are aware of their market partners, their power and expectations, and wo are prepared to implement profit-oriented customer orientation measures. (orig.)

The eGo grid model: An open source approach towards a model of German high and extra-high voltage power grids

Science.gov (United States)

Mueller, Ulf Philipp; Wienholt, Lukas; Kleinhans, David; Cussmann, Ilka; Bunke, Wolf-Dieter; Pleßmann, Guido; Wendiggensen, Jochen

2018-02-01

There are several power grid modelling approaches suitable for simulations in the field of power grid planning. The restrictive policies of grid operators, regulators and research institutes concerning their original data and models lead to an increased interest in open source approaches of grid models based on open data. By including all voltage levels between 60 kV (high voltage) and 380kV (extra high voltage), we dissolve the common distinction between transmission and distribution grid in energy system models and utilize a single, integrated model instead. An open data set for primarily Germany, which can be used for non-linear, linear and linear-optimal power flow methods, was developed. This data set consists of an electrically parameterised grid topology as well as allocated generation and demand characteristics for present and future scenarios at high spatial and temporal resolution. The usability of the grid model was demonstrated by the performance of exemplary power flow optimizations. Based on a marginal cost driven power plant dispatch, being subject to grid restrictions, congested power lines were identified. Continuous validation of the model is nescessary in order to reliably model storage and grid expansion in progressing research.

Power grid operation risk management: V2G deployment for sustainable development

Science.gov (United States)

Haddadian, Ghazale J.

The production, transmission, and delivery of cost--efficient energy to supply ever-increasing peak loads along with a quest for developing a low-carbon economy require significant evolutions in the power grid operations. Lower prices of vast natural gas resources in the United States, Fukushima nuclear disaster, higher and more intense energy consumptions in China and India, issues related to energy security, and recent Middle East conflicts, have urged decisions makers throughout the world to look into other means of generating electricity locally. As the world look to combat climate changes, a shift from carbon-based fuels to non-carbon based fuels is inevitable. However, the variability of distributed generation assets in the electricity grid has introduced major reliability challenges for power grid operators. While spearheading sustainable and reliable power grid operations, this dissertation develops a multi-stakeholder approach to power grid operation design; aiming to address economic, security, and environmental challenges of the constrained electricity generation. It investigates the role of Electric Vehicle (EV) fleets integration, as distributed and mobile storage assets to support high penetrations of renewable energy sources, in the power grid. The vehicle-to-grid (V2G) concept is considered to demonstrate the bidirectional role of EV fleets both as a provider and consumer of energy in securing a sustainable power grid operation. The proposed optimization modeling is the application of Mixed-Integer Linear Programing (MILP) to large-scale systems to solve the hourly security-constrained unit commitment (SCUC) -- an optimal scheduling concept in the economic operation of electric power systems. The Monte Carlo scenario-based approach is utilized to evaluate different scenarios concerning the uncertainties in the operation of power grid system. Further, in order to expedite the real-time solution of the proposed approach for large-scale power systems

Power Talk in DC Micro Grids

DEFF Research Database (Denmark)

Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

2015-01-01

Power talk is a novel concept for communication among units in a Micro Grid (MG), where information is sent by using power electronics as modems and the common bus of the MG as a communication medium. The technique is implemented by modifying the droop control parameters from the primary control...

A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... performed on a 3-kW two-stage single-phase grid-connected PV system, where the power reserve control is achieved upon demands....

GRID : unlimited computing power on your desktop Conference MT17

CERN Multimedia

2001-01-01

The Computational GRID is an analogy to the electrical power grid for computing resources. It decouples the provision of computing, data, and networking from its use, it allows large-scale pooling and sharing of resources distributed world-wide. Every computer, from a desktop to a mainframe or supercomputer, can provide computing power or data for the GRID. The final objective is to plug your computer into the wall and have direct access to huge computing resources immediately, just like plugging-in a lamp to get instant light. The GRID will facilitate world-wide scientific collaborations on an unprecedented scale. It will provide transparent access to major distributed resources of computer power, data, information, and collaborations.

Development and Testing of a Prototype Grid-Tied Photovoltaic Power System

Science.gov (United States)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) has developed and tested a prototype 2 kW DC grid-tied photovoltaic (PV) power system at the Center. The PV system has generated in excess of 6700 kWh since operation commenced in July 2006. The PV system is providing power to the GRC grid for use by all. Operation of the prototype PV system has been completely trouble free. A grid-tied PV power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. Based upon the success of the prototype PV system, additional PV power system expansion at GRC is under consideration. The prototype grid-tied PV power system was successfully designed and developed which served to validate the basic principles described, and the theoretical work that was performed. The report concludes that grid-tied photovoltaic power systems are reliable, maintenance free, long life power systems, and are of significant value to NASA and the community.

Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

Science.gov (United States)

2016-09-01

With the growing demand for a reliable electrical grid, backup power supplies and energy management systems are a necessity. Systems such as server...ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER

A study on economic power dispatch grid connected PV power plant in educational institutes

Science.gov (United States)

Singh, Kuldip; Kumar, M. Narendra; Mishra, Satyasis

2018-04-01

India has main concerns on environment and escalation of fuel prices with respect to diminution of fossil fuel reserves and the major focus on renewable Energy sources for power generation to fulfill the present and future energy demand. Installation of PV power plants in the Educational Institutions has grown up drastically throughout India. More PV power plant are integrated with load and grid through net metering. Therefore, this paper is an analysis of the 75kWp PV plant at chosen buses, considering the need of minimum demand from the grid. The case study is carried out for different generation level throughout the day and year w.r.t load and climate changes, load sharing on grid. The economic dispatch model developed for PV plant integrated with Grid.

High Performance Reduced Order Models for Wind Turbines with Full-Scale Converters Applied on Grid Interconnection Studies

DEFF Research Database (Denmark)

Pereira, Heverton A.; F. Cupertino, Allan; Teodorescu, Remus

2014-01-01

Wind power has achieved technological evolution, and Grid Code (GC) requirements forced wind industry consolidation in the last three decades. However, more studies are necessary to understand how the dynamics inherent in this energy source interact with the power system. Traditional energy...... of Absolute Error (NIAE). Models are analyzed during wind speed variations and balanced voltage dip. During faults, WPPs must be able to supply reactive power to the grid, and this characteristic is analyzed. Using the proposed performance index, it is possible to conclude if a reduced order model is suitable...

Grid Integration of Offshore Wind Farms via VSC-HVDC – Dynamic Stability Study

DEFF Research Database (Denmark)

Liu, Hongzhi

farms could seriously impact the operation and stability of their interconnected power system. To assist in maintaining the power system stability when large disturbances occur in the grid, modern offshore wind farms consisting of variable-speed wind turbines are required to provide ancillary services...... such as voltage and frequency control. The greater distance to shore makes commonly used high voltage AC (HVAC) connection unsuitable economically and technically for large offshore wind farms. Alternatively, voltage source converter (VSC)-based high voltage DC (HVDC) transmission becomes more attractive...... and practical to integrate large-scale offshore wind farms into the onshore power grid, owing to its high capacity, advanced controllability and stabilization potential for AC networks etc. In this dissertation, some of the key technical issues with grid integration of large-scale offshore wind farms via VSC...

Prospects for investment in large-scale, grid-connected solar power in Africa

DEFF Research Database (Denmark)

Hansen, Ulrich Elmer; Nygaard, Ivan; Pedersen, Mathilde Brix

since the 1990s have changed the competiveness of solar PV in all markets, ranging from individual households via institutions to mini-grids and grid-connected installations. In volume and investment, the market for large-scale grid-connected solar power plants is by far the most important......-scale investments in grid-connected solar power plants and local assembly facilities for PV panels, have exceeded even optimistic scenarios. Finally, therefore, there seem to be bright prospects for investment in large-scale grid-connected solar power in Africa....

The progresses of superconducting technology for power grid last decade in China

Energy Technology Data Exchange (ETDEWEB)

Xiao, Liye; Gu, Hong Wei [Applied Superconductivity Laboratory, Chinese Academy of Sciences, Beijing (China)

2015-03-15

With the increasing development of renewable energy, it is expected that large-scale renewable power would be transported from the west and north area of China to the east and south area. For this reason, it will be necessary to develop a wide-area power grid in which the renewable energy would be the dominant power source, and the power grid will be faced by some critical challenges such as long-distance large-capacity power transmission, the stability of the wide-area power grid and the land use problem for the power grid. The superconducting technology for power (STP) would be a possible alternative for the development of China’s future power grid. In last decade, STP has been extensively developed in China. In this paper, we present an overview of the R and D of STP last decade in China including: 1) the development of high temperature superconducting (HTS) materials, 2) DC power cables, 3) superconducting power substations, 4) fault current limiters and 5) superconducting magnetic energy storage (SMES)

The progresses of superconducting technology for power grid last decade in China

International Nuclear Information System (INIS)

Xiao, Liye; Gu, Hong Wei

2015-01-01

With the increasing development of renewable energy, it is expected that large-scale renewable power would be transported from the west and north area of China to the east and south area. For this reason, it will be necessary to develop a wide-area power grid in which the renewable energy would be the dominant power source, and the power grid will be faced by some critical challenges such as long-distance large-capacity power transmission, the stability of the wide-area power grid and the land use problem for the power grid. The superconducting technology for power (STP) would be a possible alternative for the development of China’s future power grid. In last decade, STP has been extensively developed in China. In this paper, we present an overview of the R and D of STP last decade in China including: 1) the development of high temperature superconducting (HTS) materials, 2) DC power cables, 3) superconducting power substations, 4) fault current limiters and 5) superconducting magnetic energy storage (SMES)

Efficient design and simulation of an expandable hybrid (wind-photovoltaic) power system with MPPT and inverter input voltage regulation features in compliance with electric grid requirements

Energy Technology Data Exchange (ETDEWEB)

Skretas, Sotirios B.; Papadopoulos, Demetrios P. [Electrical Machines Laboratory, Department of Electrical and Computer Engineering, Democritos University of Thrace (DUTH), 12 V. Sofias, 67100 Xanthi (Greece)

2009-09-15

In this paper an efficient design along with modeling and simulation of a transformer-less small-scale centralized DC - bus Grid Connected Hybrid (Wind-PV) power system for supplying electric power to a single phase of a three phase low voltage (LV) strong distribution grid are proposed and presented. The main components of the hybrid system are: a PV generator (PVG); and an array of horizontal-axis, fixed-pitch, small-size, variable-speed wind turbines (WTs) with direct-driven permanent magnet synchronous generator (PMSG) having an embedded uncontrolled bridge rectifier. An overview of the basic theory of such systems along with their modeling and simulation via Simulink/MATLAB software package are presented. An intelligent control method is applied to the proposed configuration to simultaneously achieve three desired goals: to extract maximum power from each hybrid power system component (PVG and WTs); to guarantee DC voltage regulation/stabilization at the input of the inverter; to transfer the total produced electric power to the electric grid, while fulfilling all necessary interconnection requirements. Finally, a practical case study is conducted for the purpose of fully evaluating a possible installation in a city site of Xanthi/Greece, and the practical results of the simulations are presented. (author)

Integration of distributed energy resources into low voltage grid: A market-based multiperiod optimization model

Energy Technology Data Exchange (ETDEWEB)

Mashhour, Elahe; Moghaddas-Tafreshi, S.M. [Faculty of Electrical Engineering, K.N. Toosi University of Technology, Seyd Khandan, P.O. Box 16315-1355, Shariati, Tehran (Iran)

2010-04-15

This paper develops a multiperiod optimization model for an interconnected micro grid with hierarchical control that participates in wholesale energy market to maximize its benefit (i.e. revenues-costs). In addition to the operational constraints of distributed energy resources (DER) including both inter-temporal and non-inter-temporal types, the adequacy and steady-state security constraints of micro grid and its power losses are incorporated in the optimization model. In the presented model, DER are integrated into low voltage grid considering both technical and economical aspects. This integration as a micro grid can participate in wholesale energy market as an entity with dual role including producer and consumer based on the direction of exchanged power. The developed model is evaluated by testing on a micro grid considering different cases and the results are analyzed. (author)

Reconfiguring grid-interfacing converters for power quality improvement

NARCIS (Netherlands)

Wang, F.; Duarte, J.L.; Hendrix, M.A.M.; Encica, L.; Gysen, B.L.J.; Jansen, J.W.; Krop, D.C.J.

2008-01-01

In this paper reconfiguration of grid-interfacing converters is proposed for power quality improvement. In addition to the traditional function of delivering energy between distributed sources and the utility grid, more flexible ancillary functions can be integrated into the control of

Predictive Smart Grid Control with Exact Aggregated Power Constraints

DEFF Research Database (Denmark)

Trangbæk, K; Petersen, Mette Højgaard; Bendtsen, Jan Dimon

2012-01-01

of autonomous consumers. The control system is tasked with balancing electric power production and consumption within the smart grid, and makes active use of the flexibility of a large number of power producing and/or power consuming units. The load variations on the grid arise on one hand from varying......This chapter deals with hierarchical model predictive control (MPC) of smart grid systems. The design consists of a high-level MPC controller, a second level of so-called aggregators,which reduces the computational and communication related load on the high-level control, and a lower level...... consumption, and on the other hand from natural variations in power production from e.g. wind turbines. The consumers represent energy-consuming units such as heat pumps, car batteries etc. These units obviously have limits on how much power and energy they can consume at any given time, which impose...

Methods and apparatus of analyzing electrical power grid data

Science.gov (United States)

Hafen, Ryan P.; Critchlow, Terence J.; Gibson, Tara D.

2017-09-05

Apparatus and methods of processing large-scale data regarding an electrical power grid are described. According to one aspect, a method of processing large-scale data regarding an electrical power grid includes accessing a large-scale data set comprising information regarding an electrical power grid; processing data of the large-scale data set to identify a filter which is configured to remove erroneous data from the large-scale data set; using the filter, removing erroneous data from the large-scale data set; and after the removing, processing data of the large-scale data set to identify an event detector which is configured to identify events of interest in the large-scale data set.

Experimental Evaluation of Grid Support Enabled PV Inverter Response to Abnormal Grid Conditions: Preprint

Energy Technology Data Exchange (ETDEWEB)

Nelson, Austin; Martin, Gregory; Hurtt, James

2017-05-08

As revised interconnection standards for grid-tied photovoltaic (PV) inverters address new advanced grid support functions (GSFs), there is increasing interest in inverter performance in the case of abnormal grid conditions. The growth of GSF-enabled inverters has outpaced the industry standards that define their operation, although recently published updates to UL1741 with Supplement SA define test conditions for GSFs such as volt-var control, frequency-watt control, and volt-age/frequency ride-through, among others. A comparative experimental evaluation has been completed on four commercially available, three-phase PV inverters in the 24.0-39.8 kVA power range on their GSF capability and the effect on abnormal grid condition response. This study examines the impact particular GSF implementations have on run-on times during islanding conditions, peak voltages in load rejection overvoltage scenarios, and peak currents during single-phase and three-phase fault events for individual inverters. This report reviews comparative test data, which shows that GSFs have little impact on the metrics of interest in most tests cases.

Emission factor of gases from the greenhouse effect for the brazilian interconnected system; Fator de emissao de gases de efeito estufa para o sistema interligado brasileiro

Energy Technology Data Exchange (ETDEWEB)

Esparta, A. Ricardo J. [Ecoinvest Carbon S.A., Sao Paulo, SP (Brazil)]. E-mail: esparta@iee.usp.br; esparta@ecoinvestcarbon.com; Fernandez, Pablo [EcoSecurities, Rio de Janeiro, RJ (Brazil)]. E-mail: pablo.fernandez@ecosecurities.com.br; Costa, David Freire da [Econergy Brasil, Sao Paulo, SP (Brazil)]. E-mail: freire@econergy.com.br

2006-07-01

The participation of new power generation projects of the Brazilian interconnected system in the Clean Development Mechanism of the Kyoto Protocol demand the definition of greenhouse gases baseline emission scenarios and monitoring methodologies. The present paper describes the reasoning behind approved methodologies for capacity addition from renewable sources as well as carries out the calculation of the emission factor for the Brazilian interconnected grid. (author)

Solving LFC problem in an interconnected power system using superconducting magnetic energy storage

Energy Technology Data Exchange (ETDEWEB)

Farahani, Mohsen, E-mail: mhs.farahani@gmail.com [Sama Technical and Vocational Training College, Islamic Azad University, Karaj Branch, Karaj (Iran, Islamic Republic of); Ganjefar, Soheil [Department of Electrical Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

2013-04-15

Highlights: ► Load frequency control of PID type is combined with a SMES. ► Damping speed of frequency and tie-line power flow deviations are considerably increased. ► Optimal parameters of PID and SMES control loop are obtained by PS optimization. -- Abstract: This paper proposes the combination of a load frequency control (LFC) with superconducting magnetic energy storage (SMES) to solve the LFC problem in interconnected power systems. By using this combination, the speed damping of frequency and tie-line power flow deviations is considerably increased. A new control strategy of SMES is proposed in this paper. The problem of determining optimal parameters of PID and SMES control loop is considered as an optimization problem and a pattern search algorithm (PS) optimization is employed to solve it. The simulation results show that if an SMES unit is installed in an interconnected power system, in addition to eliminating oscillations and deviations, the settling time in the frequency and tie-line power flow responses is considerably reduced.

Solving LFC problem in an interconnected power system using superconducting magnetic energy storage

International Nuclear Information System (INIS)

Farahani, Mohsen; Ganjefar, Soheil

2013-01-01

Highlights: ► Load frequency control of PID type is combined with a SMES. ► Damping speed of frequency and tie-line power flow deviations are considerably increased. ► Optimal parameters of PID and SMES control loop are obtained by PS optimization. -- Abstract: This paper proposes the combination of a load frequency control (LFC) with superconducting magnetic energy storage (SMES) to solve the LFC problem in interconnected power systems. By using this combination, the speed damping of frequency and tie-line power flow deviations is considerably increased. A new control strategy of SMES is proposed in this paper. The problem of determining optimal parameters of PID and SMES control loop is considered as an optimization problem and a pattern search algorithm (PS) optimization is employed to solve it. The simulation results show that if an SMES unit is installed in an interconnected power system, in addition to eliminating oscillations and deviations, the settling time in the frequency and tie-line power flow responses is considerably reduced

A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

OpenAIRE

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Track...

Network integration of distributed power generation

Science.gov (United States)

Dondi, Peter; Bayoumi, Deia; Haederli, Christoph; Julian, Danny; Suter, Marco

The world-wide move to deregulation of the electricity and other energy markets, concerns about the environment, and advances in renewable and high efficiency technologies has led to major emphasis being placed on the use of small power generation units in a variety of forms. The paper reviews the position of distributed generation (DG, as these small units are called in comparison with central power plants) with respect to the installation and interconnection of such units with the classical grid infrastructure. In particular, the status of technical standards both in Europe and USA, possible ways to improve the interconnection situation, and also the need for decisions that provide a satisfactory position for the network operator (who remains responsible for the grid, its operation, maintenance and investment plans) are addressed.

Power control and management of the grid containing largescale wind power systems

Science.gov (United States)

Aula, Fadhil Toufick

The ever increasing demand for electricity has driven many countries toward the installation of new generation facilities. However, concerns such as environmental pollution and global warming issues, clean energy sources, high costs associated with installation of new conventional power plants, and fossil fuels depletion have created many interests in finding alternatives to conventional fossil fuels for generating electricity. Wind energy is one of the most rapidly growing renewable power sources and wind power generations have been increasingly demanded as an alternative to the conventional fossil fuels. However, wind power fluctuates due to variation of wind speed. Therefore, large-scale integration of wind energy conversion systems is a threat to the stability and reliability of utility grids containing these systems. They disturb the balance between power generation and consumption, affect the quality of the electricity, and complicate load sharing and load distribution managing and planning. Overall, wind power systems do not help in providing any services such as operating and regulating reserves to the power grid. In order to resolve these issues, research has been conducted in utilizing weather forecasting data to improve the performance of the wind power system, reduce the influence of the fluctuations, and plan power management of the grid containing large-scale wind power systems which consist of doubly-fed induction generator based energy conversion system. The aims of this research, my dissertation, are to provide new methods for: smoothing the output power of the wind power systems and reducing the influence of their fluctuations, power managing and planning of a grid containing these systems and other conventional power plants, and providing a new structure of implementing of latest microprocessor technology for controlling and managing the operation of the wind power system. In this research, in order to reduce and smooth the fluctuations, two

Delta Power Control Strategy for Multistring Grid-Connected PV Inverters

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

, is required for grid support (e.g., during frequency deviation). In this paper, a cost-effective solution to realize delta power control (DPC) for grid-connected PV systems is presented, where the multistring PV inverter configuration is adopted. This control strategy is a combination of maximum power point...... tracking (MPPT) and constant power generation (CPG) modes. In this control scheme, one PV string operating in the MPPT mode estimates the available power, whereas the other PV strings regulate the total PV power by the CPG control strategy in such a way that the delta power constraint for the entire PV...... system is achieved. Simulations and experiments have been performed on a 3-kW single-phase grid-connected PV system. The results have confirmed the effectiveness of the proposed DPC strategy, where the power reserve according to the delta power constraint is achieved under several operating conditions....

Coordinated control of wind power plants in offshore HVDC grids

DEFF Research Database (Denmark)

Sakamuri, Jayachandra N.

2017-01-01

power between different countries, and different synchronous areas. It is very likely that they will then be combined with offshore wind power plant (OWPP) connections in the North Sea, transforming it in a multi terminal DC (MTDC) grid and, therefore, in a fully meshed offshore DC grid in near future......During the recent years, there has been a significant penetration of offshore wind power into the power system and this trend is expected to continue in the future. The North Sea in Europe has higher potential for offshore wind power; therefore, the North Seas Countries' Offshore Grid initiative....... However, increased penetration of offshore wind power into the power system poses several challenges to its security. This thesis deals with two main research challenges, (1) Develop, and analyze the coordinated control strategies for AC voltage and reactive power control in the cluster of OWPPs connected...

Neuro-Fuzzy Computational Technique to Control Load Frequency in Hydro-Thermal Interconnected Power System

Science.gov (United States)

Prakash, S.; Sinha, S. K.

2015-09-01

In this research work, two areas hydro-thermal power system connected through tie-lines is considered. The perturbation of frequencies at the areas and resulting tie line power flows arise due to unpredictable load variations that cause mismatch between the generated and demanded powers. Due to rising and falling power demand, the real and reactive power balance is harmed; hence frequency and voltage get deviated from nominal value. This necessitates designing of an accurate and fast controller to maintain the system parameters at nominal value. The main purpose of system generation control is to balance the system generation against the load and losses so that the desired frequency and power interchange between neighboring systems are maintained. The intelligent controllers like fuzzy logic, artificial neural network (ANN) and hybrid fuzzy neural network approaches are used for automatic generation control for the two area interconnected power systems. Area 1 consists of thermal reheat power plant whereas area 2 consists of hydro power plant with electric governor. Performance evaluation is carried out by using intelligent (ANFIS, ANN and fuzzy) control and conventional PI and PID control approaches. To enhance the performance of controller sliding surface i.e. variable structure control is included. The model of interconnected power system has been developed with all five types of said controllers and simulated using MATLAB/SIMULINK package. The performance of the intelligent controllers has been compared with the conventional PI and PID controllers for the interconnected power system. A comparison of ANFIS, ANN, Fuzzy and PI, PID based approaches shows the superiority of proposed ANFIS over ANN, fuzzy and PI, PID. Thus the hybrid fuzzy neural network controller has better dynamic response i.e., quick in operation, reduced error magnitude and minimized frequency transients.

Economic MPC for Power Management in the Smart Grid

DEFF Research Database (Denmark)

Hovgaard, Tobias Gybel; Edlund, Kristian; Jørgensen, John Bagterp

2011-01-01

To increase the amount of green energy (e.g. solar and wind) significantly a new intelligent electrical infrastructure is needed. We must not only control the production of electricity but also the consumption in an efficient and proactive manner. This future intelligent grid is in Europe known...... as the SmartGrid. In this paper we demonstrate the use of Economic Model Predictive Control to operate a portfolio of power generators and consumers such that the cost of producing the required power is minimized. With conventional coal and gas fired power generators representing the controllable power...

The power grid monitoring promotion of Liaoning December 14th accident

Science.gov (United States)

Zhou, Zhi; Gao, Ziji; He, Xiaoyang; Li, Tie; Jin, Xiaoming; Wang, Mingkai; Qu, Zhi; Sun, Chenguang

2018-02-01

This paper introduces the main responsibilities of power grid monitoring and the accident of Liaoning Power Grid 500kV Xujia transformer substation at December 14th, 2016. This paper analyzes the problems exposed in this accident from the aspects of abnormal information judgment, fault information collection, auxiliary video monitoring, online monitoring of substation equipment, puts forward the corresponding improvement methods and summarizes the methods of improving the professional level of power grid equipment monitoring.

The advanced smart grid edge power driving sustainability

CERN Document Server

Carvallo, Andres

2011-01-01

Placing emphasis on practical ""how-to"" guidance, this cutting-edge resource provides you with a first-hand, insider's perspective on the advent and evolution of smart grids in the 21st century (smart grid 1.0). You gain a thorough understanding of the building blocks that comprise basic smart grids, including power plant, transmission substation, distribution, and meter automation. Moreover, this forward-looking volume explores the next step of this technology's evolution. It provides a detailed explanation of how an advanced smart grid incorporates demand response with smart appliances and

Autonomous Operation of Hybrid Microgrid with AC and DC Sub-Grids

DEFF Research Database (Denmark)

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...

Minimization of Load Variance in Power Grids—Investigation on Optimal Vehicle-to-Grid Scheduling

Directory of Open Access Journals (Sweden)

Kang Miao Tan

2017-11-01

Full Text Available The introduction of electric vehicles into the transportation sector helps reduce global warming and carbon emissions. The interaction between electric vehicles and the power grid has spurred the emergence of a smart grid technology, denoted as vehicle-to grid-technology. Vehicle-to-grid technology manages the energy exchange between a large fleet of electric vehicles and the power grid to accomplish shared advantages for the vehicle owners and the power utility. This paper presents an optimal scheduling of vehicle-to-grid using the genetic algorithm to minimize the power grid load variance. This is achieved by allowing electric vehicles charging (grid-to-vehicle whenever the actual power grid loading is lower than the target loading, while conducting electric vehicle discharging (vehicle-to-grid whenever the actual power grid loading is higher than the target loading. The vehicle-to-grid optimization algorithm is implemented and tested in MATLAB software (R2013a, MathWorks, Natick, MA, USA. The performance of the optimization algorithm depends heavily on the setting of the target load, power grid load and capability of the grid-connected electric vehicles. Hence, the performance of the proposed algorithm under various target load and electric vehicles’ state of charge selections were analysed. The effectiveness of the vehicle-to-grid scheduling to implement the appropriate peak load shaving and load levelling services for the grid load variance minimization is verified under various simulation investigations. This research proposal also recommends an appropriate setting for the power utility in terms of the selection of the target load based on the electric vehicle historical data.

Sensorless Reserved Power Control Strategy for Two-Stage Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

Due to still increasing penetration level of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A reserved power control, where the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the reserved power control for grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... to achieve the power reserve. In this method, the irradiance measurements that have been used in conventional control schemes to estimate the available PV power are not required, and thereby being a sensorless solution. Simulations and experimental tests have been performed on a 3-kW two-stage single...

EXPERIMENTAL STUDY AND PERFORMANCE OF SOLAR ENERGY SYSTEM WITH GRID CONNECTED POWER SUPPLY

OpenAIRE

Pradeep Bharti; Dr. A.K.Sharma

2017-01-01

In this paper , we are analyzed about the solar power with grid connection using of various component such as PV Cells battery inverter, and grid power connection , in this way we are connected the grid power and solar power , after that finally we are analyzed the power quality of output with the help of various devices.

Control Aspects of a LCL Grid-Connected Green Power Inverter

DEFF Research Database (Denmark)

Kjær, Søren Bækhøj; Andersen, Gert Karmisholt; Klumpner, Christian

2002-01-01

A full-bridge inverter for interfacing the utility grid is developed for using in a Green Power Inverter application. The inverter is feed from an arbitrary green power source (fuel cell, photovoltaic, small wind turbine etc.) through a rectifier into the dc-link. In order to maintain a sinusoidal...... grid current with low harmonic distortion and a high power factor, the inverter is controlled to emulate a negative resistance towards the grid. The size of the emulated resistor is determined by the dc-link voltage controller, which tries to maintain a constant dc-link voltage. This is however...

Smart Grids as keys to a successful energy transition

International Nuclear Information System (INIS)

Meunier, Stephane

2013-07-01

This publication addresses several issues related to the role of smart grids in energy transition. The contributions discuss whether the future of smart grid markets can be found in developing countries, outline that the deployment of smart counters announces the development of smart grids in France, comment the search for a new business model for the smart grid market, and question the role of power storage as a key for the integration of renewable energies into the grid. They also address the case of French non interconnected areas which could be a laboratory to develop and test smart grids. They outline that smart grids display an economic logic against energy poverty, that smart grids in developing countries could be a lever against blackouts and electricity thefts, and that they can be a solution for the electrification of rural areas in developing countries. They present energy cooperatives as a successful model for smart grid projects. A last contribution addresses the smart management of water as a solution to preserve the resource while generating profits

The impact of the year 2000 issue on electricity grid performance and nuclear power plant operation in Bulgaria, the Russian Federation and Slovakia

International Nuclear Information System (INIS)

1999-07-01

The Y2K date conversion is a potential source of problems to the operation of nuclear power plants through external events and interfaces with electrical power systems, telecommunication systems, and other supporting infrastructures, even if diagnostic and corrective actions within the plant itself, both planned or implemented, are successful. At the end of 1998 there were 425 nuclear power plants in operation in 31 Member States. Most countries and regions are conducting intensive diagnostic and corrective activities to 'find and fix' Y2K software (including embedded software) and equipment problems in their nuclear power plants. These efforts are supplemented by contingency plans. Other countries and regions have not been making comparable efforts and are relying mainly on contingency planning and preparedness. Results of diagnostic and corrective activities can be of benefit to all Member States. Activities on 'find and fix' Y2K problems in electricity grid control systems and computer related technology in national and regional dispatch centers could be of considerable benefit due to the widespread use of the same components, equipment, and software. Consistent with the objectives of the International Atomic Energy Agency's Y2K program, an experts meeting was convened to collect information on Y2K activities related to grid operation in countries that operate nuclear power plants and also to identify specific actions to be taken and issues to be addressed in connection with expected grid disturbances. The countries of eastern Europe and the Russian Federation were considered to be a very important region due to delays in taking Y2K corrective actions but also due to the similarity of their electricity grid systems both in components and design but also in mode of operation. Most of these countries either operate their own nuclear power plants or are linked through their electricity grid interconnections to a neighboring country that operates nuclear power

A New Control Method to Mitigate Power Fluctuations for Grid Integrated PV/Wind Hybrid Power System Using Ultracapacitors

Science.gov (United States)

Jayalakshmi, N. S.; Gaonkar, D. N.

2016-08-01

The output power obtained from solar-wind hybrid system fluctuates with changes in weather conditions. These power fluctuations cause adverse effects on the voltage, frequency and transient stability of the utility grid. In this paper, a control method is presented for power smoothing of grid integrated PV/wind hybrid system using ultracapacitors in a DC coupled structure. The power fluctuations of hybrid system are mitigated and smoothed power is supplied to the utility grid. In this work both photovoltaic (PV) panels and the wind generator are controlled to operate at their maximum power point. The grid side inverter control strategy presented in this paper maintains DC link voltage constant while injecting power to the grid at unity power factor considering different operating conditions. Actual solar irradiation and wind speed data are used in this study to evaluate the performance of the developed system using MATLAB/Simulink software. The simulation results show that output power fluctuations of solar-wind hybrid system can be significantly mitigated using the ultracapacitor based storage system.

Transmission Technologies and Operational Characteristic Analysis of Hybrid UHV AC/DC Power Grids in China

Science.gov (United States)

Tian, Zhang; Yanfeng, Gong

2017-05-01

In order to solve the contradiction between demand and distribution range of primary energy resource, Ultra High Voltage (UHV) power grids should be developed rapidly to meet development of energy bases and accessing of large-scale renewable energy. This paper reviewed the latest research processes of AC/DC transmission technologies, summarized the characteristics of AC/DC power grids, concluded that China’s power grids certainly enter a new period of large -scale hybrid UHV AC/DC power grids and characteristics of “strong DC and weak AC” becomes increasingly pro minent; possible problems in operation of AC/DC power grids was discussed, and interaction or effect between AC/DC power grids was made an intensive study of; according to above problems in operation of power grids, preliminary scheme is summarized as fo llows: strengthening backbone structures, enhancing AC/DC transmission technologies, promoting protection measures of clean energ y accessing grids, and taking actions to solve stability problems of voltage and frequency etc. It’s valuable for making hybrid UHV AC/DC power grids adapt to operating mode of large power grids, thus guaranteeing security and stability of power system.

Grid Simulator for Testing a Wind Turbine on Offshore Floating Platform

Energy Technology Data Exchange (ETDEWEB)

Gevorgian, V.

2012-02-01

An important aspect of such offshore testing of a wind turbine floating platform is electrical loading of the wind turbine generator. An option of interconnecting the floating wind turbine with the onshore grid via submarine power cable is limited by many factors such as costs and associated environmental aspects (i.e., an expensive and lengthy sea floor study is needed for cable routing, burial, etc). It appears to be a more cost effective solution to implement a standalone grid simulator on a floating platform itself for electrical loading of the test wind turbine. Such a grid simulator must create a stable fault-resilient voltage and frequency bus (a micro grid) for continuous operation of the test wind turbine. In this report, several electrical topologies for an offshore grid simulator were analyzed and modeled.

Power systems signal processing for smart grids

NARCIS (Netherlands)

Ribeiro, P.F.; Duque, C.A.; Da Silveira, P.M.; Cerqueira, A.S.

2013-01-01

With special relation to smart grids, this book provides clear and comprehensive explanation of how Digital Signal Processing (DSP) and Computational Intelligence (CI) techniques can be applied to solve problems in the power system. Its unique coverage bridges the gap between DSP, electrical power

A Reduced Wind Power Grid Model for Research and Education

DEFF Research Database (Denmark)

Akhmatov, Vladislav; Lund, Torsten; Hansen, Anca Daniela

2007-01-01

A reduced grid model of a transmission system with a number of central power plants, consumption centers, local wind turbines and a large offshore wind farm is developed and implemented in the simulation tool PowerFactory (DIgSILENT). The reduced grid model is given by Energinet.dk, Transmission...

The Impact of the Topology on Cascading Failures in a Power Grid Model

NARCIS (Netherlands)

Koç, Y.; Warnier, M.; Mieghem, P. van; Kooij, R.E.; Brazier, F.M.T.

2014-01-01

Cascading failures are one of the main reasons for large scale blackouts in power transmission grids. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. Currently, the impact of the topology on grid robustness is mainly

Autonomous Energy Grids: Preprint

Energy Technology Data Exchange (ETDEWEB)

Kroposki, Benjamin D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bernstein, Andrey [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Yingchen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hodge, Brian S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-10-04

With much higher levels of distributed energy resources - variable generation, energy storage, and controllable loads just to mention a few - being deployed into power systems, the data deluge from pervasive metering of energy grids, and the shaping of multi-level ancillary-service markets, current frameworks to monitoring, controlling, and optimizing large-scale energy systems are becoming increasingly inadequate. This position paper outlines the concept of 'Autonomous Energy Grids' (AEGs) - systems that are supported by a scalable, reconfigurable, and self-organizing information and control infrastructure, can be extremely secure and resilient (self-healing), and self-optimize themselves in real-time for economic and reliable performance while systematically integrating energy in all forms. AEGs rely on scalable, self-configuring cellular building blocks that ensure that each 'cell' can self-optimize when isolated from a larger grid as well as partaking in the optimal operation of a larger grid when interconnected. To realize this vision, this paper describes the concepts and key research directions in the broad domains of optimization theory, control theory, big-data analytics, and complex system modeling that will be necessary to realize the AEG vision.

Cyber physical systems approach to smart electric power grid

CERN Document Server

Khaitan, Siddhartha Kumar; Liu, Chen Ching

2015-01-01

This book documents recent advances in the field of modeling, simulation, control, security and reliability of Cyber- Physical Systems (CPS) in power grids. The aim of this book is to help the reader gain insights into working of CPSs and understand their potential in transforming the power grids of tomorrow. This book will be useful for all those who are interested in design of cyber-physical systems, be they students or researchers in power systems, CPS modeling software developers, technical marketing professionals and business policy-makers.

Modeling and control of sustainable power systems. Towards smarter and greener electric grids

Energy Technology Data Exchange (ETDEWEB)

Lingfeng Wang (ed.) [Toledo Univ., OH (United States). Electrical Engineering and Computer Science Dept.

2012-07-01

The concept of the smart grid promises the world an efficient and intelligent approach of managing energy production, transportation, and consumption by incorporating intelligence, efficiency, and optimality into the power grid. Both energy providers and consumers can take advantage of the convenience, reliability, and energy savings achieved by real-time and intelligent energy management. To this end, the current power grid is experiencing drastic changes and upgrades. For instance, more significant green energy resources such as wind power and solar power are being integrated into the power grid, and higher energy storage capacity is being installed in order to mitigate the intermittency issues brought about by the variable energy resources. At the same time, novel power electronics technologies and operating strategies are being invented and adopted. For instance, Flexible AC transmission systems and phasor measurement units are two promising technologies for improving the power system reliability and power quality. Demand side management will enable the customers to manage the power loads in an active fashion. As a result, modeling and control of modern power grids pose great challenges due to the adoption of new smart grid technologies. In this book, chapters regarding representative applications of smart grid technologies written by world-renowned experts are included, which explain in detail various innovative modeling and control methods. (orig.)

Digital Grid: Transforming the Electric Power Grid into an Innovation Engine for the United States

OpenAIRE

Chakrabortty, Aranya; Huang, Alex

2017-01-01

The electric power grid is one of the largest and most complex infrastructures ever built by mankind. Modern civilization depends on it for industry production, human mobility, and comfortable living. However, many critical technologies such as the 60 Hz transformers were developed at the beginning of the 20th century and have changed very little since then.1 The traditional unidirectional power from the generation to the customer through the transmission-distribution grid has also changed no...

Active and reactive power neurocontroller for grid-connected photovoltaic generation system

Directory of Open Access Journals (Sweden)

I. Abadlia

2016-03-01

Full Text Available Many researchers have contributed to the development of a firm foundation for analysis and design of control applications in grid-connected renewable energy sources. This paper presents an intelligent control algorithm fond on artificial neural networks for active and reactive power controller in grid-connected photovoltaic generation system. The system is devices into two parts in which each part contains an inverter with control algorithm. A DC/DC converter in output voltage established by control magnitude besides maximum power point tracker algorithm always finds optimal power of the PV array in use. A DC/AC hysteresis inverter designed can synchronize a sinusoidal current output with the grid voltage and accurate an independent active and reactive power control. Simulation results confirm the validation of the purpose. Neurocontroller based active and reactive power presents an efficiency control that guarantees good response to the steps changing in active and reactive power with an acceptable current/voltage synchronism. In this paper the power circuit and the control system of the presented grid-connected photovoltaic generation system is simulated and tested by MatLab/Simulink.

Active power control strategies for inverter-based distributed power generation adapted to grid-fault ride-through requirements

NARCIS (Netherlands)

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

2009-01-01

Distributed power generation is expected to deliver power into the grid without interruption during voltage dips. To improve system ride-through capabilities, a generalized active power control strategy is proposed for grid-interfacing inverters. Specifically, a current reference generation strategy

Hawaiian Electric Advanced Inverter Grid Support Function Laboratory Validation and Analysis

Energy Technology Data Exchange (ETDEWEB)

Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Prabakar, Kumar [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lundstrom, Blake [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nepal, Shaili [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hoke, Anderson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Asano, Marc [Hawaiian Electric Company, Honolulu, HI (United States); Ueda, Reid [Hawaiian Electric Company, Honolulu, HI (United States); Shindo, Jon [Hawaiian Electric Company, Honolulu, HI (United States); Kubojiri, Kandice [Hawaiian Electric Company, Honolulu, HI (United States); Ceria, Riley [Hawaiian Electric Company, Honolulu, HI (United States); Ifuku, Earle [Hawaiian Electric Company, Honolulu, HI (United States)

2016-12-01

The objective for this test plan was to better understand how to utilize the performance capabilities of advanced inverter functions to allow the interconnection of distributed energy resource (DER) systems to support the new Customer Self-Supply, Customer Grid-Supply, and other future DER programs. The purpose of this project was: 1) to characterize how the tested grid supportive inverters performed the functions of interest, 2) to evaluate the grid supportive inverters in an environment that emulates the dynamics of O'ahu's electrical distribution system, and 3) to gain insight into the benefits of the grid support functions on selected O'ahu island distribution feeders. These goals were achieved through laboratory testing of photovoltaic inverters, including power hardware-in-the-loop testing.

Remote Power Control Injection of Grid-Connected Power Converters Based on Virtual Flux

Directory of Open Access Journals (Sweden)

Nurul Fazlin Roslan

2018-02-01

Full Text Available Renewable Energy Source (RES-based power plants need to control the active and reactive power at the Point of Common Connection (PCC with the grid, in order to comply with the requirements of the Transmission System Operators (TSOs. This point is normally far away from the power converter station, and the cables and step-up transformers have a non-neglectable influence on the delivered power. In order to overcome this drawback, this paper presents a control algorithm that permits one to control remotely the power injected at the PCC, by adjusting the local controller of the Voltage Source Converters (VSCs. In this work, the synchronization with the grid is done based on the Virtual Flux (VF concept. The results reveals that the VF estimation is able to produce a reliable estimation of the grid voltage in any point of the network, and makes it possible to calculate the necessary current reference for injecting a desired active and reactive power at a point that can be some kilometres away. In this paper the main principle for this remote power control is presented. Likewise, the simulation and experimental results will be shown in order to analyse the effectiveness of the proposed system.

Demonstration of Active Power Controls by Utility-Scale PV Power Plant in an Island Grid: Preprint

Energy Technology Data Exchange (ETDEWEB)

Gevorgian, Vahan; O' Neill, Barbara

2017-02-01

The National Renewable Energy Laboratory (NREL), AES, and the Puerto Rico Electric Power Authority conducted a demonstration project on a utility-scale photovoltaic (PV) plant to test the viability of providing important ancillary services from this facility. As solar generation increases globally, there is a need for innovation and increased operational flexibility. A typical PV power plant consists of multiple power electronic inverters and can contribute to grid stability and reliability through sophisticated 'grid-friendly' controls. In this way, it may mitigate the impact of its variability on the grid and contribute to important system requirements more like traditional generators. In 2015, testing was completed on a 20-MW AES plant in Puerto Rico, and a large amount of test data was produced and analyzed that demonstrates the ability of PV power plants to provide various types of new grid-friendly controls. This data showed how active power controls can leverage PV's value from being simply an intermittent energy resource to providing additional ancillary services for an isolated island grid. Specifically, the tests conducted included PV plant participation in automatic generation control, provision of droop response, and fast frequency response.

The U.S. Smart Grid Revolution. KEMA's Perspectives for Job Creation

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-01-13

Smart Grid is a vision for the electric delivery system of the future. The Smart Grid envisions an entirely transformed electrical infrastructure. It will embody a network of devices as vast, interconnected, automated, and interactive as the Internet. Utilities and consumers will accrue returns through the convergence of power delivery and information technologies to achieve improved reliability, reduced O and M costs, avoidance of new capacity, and increased customer satisfaction. Smart Grid includes advanced sensing, control, communications, and analytic technologies such as Advanced Metering and T and D Automation. The GridWise Alliance believes that Smart Grid will: Utilize information technologies to revolutionize energy systems as they have revolutionized other aspects of U.S. business; Create value for all participants by developing and deploying technology solutions that cross enterprise and regulatory boundaries; Enhance security and reliability through an information-rich power grid that is flexible and adaptive; and Empower consumers to benefit from their participation in the operation of the power grid. This job creation analysis focuses in detail on the Advanced Metering and T and D automation aspects of Smart Grid, but also touches on the related new business opportunities around energy services, renewable installation and services, and home automation.

Assessment of Industrial Load for Demand Response across Western Interconnect

Energy Technology Data Exchange (ETDEWEB)

Alkadi, Nasr E [ORNL; Starke, Michael R [ORNL; Ma, Ookie [United States Department of Energy (DOE), Office of Efficiency and Renewable Energy (EERE)

2013-11-01

Demand response (DR) has the ability to both increase power grid reliability and potentially reduce operating system costs. Understanding the role of demand response in grid modeling has been difficult due to complex nature of the load characteristics compared to the modeled generation and the variation in load types. This is particularly true of industrial loads, where hundreds of different industries exist with varying availability for demand response. We present a framework considering industrial loads for the development of availability profiles that can provide more regional understanding and can be inserted into analysis software for further study. The developed framework utilizes a number of different informational resources, algorithms, and real-world measurements to perform a bottom-up approach in the development of a new database with representation of the potential demand response resource in the industrial sector across the U.S. This tool houses statistical values of energy and demand response (DR) potential by industrial plant and geospatially locates the information for aggregation for different territories without proprietary information. This report will discuss this framework and the analyzed quantities of demand response for Western Interconnect (WI) in support of evaluation of the cost production modeling with power grid modeling efforts of demand response.

Grid Integration Issues for Large Scale Wind Power Plants (WPPs)

DEFF Research Database (Denmark)

Wu, Qiuwei; Xu, Zhao; Østergaard, Jacob

2010-01-01

transmission system operators (TSOs) over the world have come up the grid codes to request the wind power plants (WPPs) to have more or less the same operating capability as the conventional power plants. The grid codes requirements from other TSOs are under development. This paper covers the steady state......The penetration level of wind power into the power system over the world have been increasing very fast in the last few years and is still keeping the fast growth rate. It is just a matter of time that the wind power will be comparable to the conventional power generation. Therefore, many...

Three-level grid-connected photovoltaic inverter with maximum power point tracking

International Nuclear Information System (INIS)

Tsang, K.M.; Chan, W.L.

2013-01-01

Highlight: ► This paper reports a novel 3-level grid connected photovoltaic inverter. ► The inverter features maximum power point tracking and grid current shaping. ► The inverter can be acted as an active filter and a renewable power source. - Abstract: This paper presents a systematic way of designing control scheme for a grid-connected photovoltaic (PV) inverter featuring maximum power point tracking (MPPT) and grid current shaping. Unlike conventional design, only four power switches are required to achieve three output levels and it is not necessary to use any phase-locked-loop circuitry. For the proposed scheme, a simple integral controller has been designed for the tracking of the maximum power point of a PV array based on an improved extremum seeking control method. For the grid-connected inverter, a current loop controller and a voltage loop controller have been designed. The current loop controller is designed to shape the inverter output current while the voltage loop controller can maintain the capacitor voltage at a certain level and provide a reference inverter output current for the PV inverter without affecting the maximum power point of the PV array. Experimental results are included to demonstrate the effectiveness of the tracking and control scheme.

Electrical Market Management Considering Power System Constraints in Smart Distribution Grids

Directory of Open Access Journals (Sweden)

Poria Hasanpor Divshali

2016-05-01

Full Text Available Rising demand, climate change, growing fuel costs, outdated power system infrastructures, and new power generation technologies have made renewable distribution generators very attractive in recent years. Because of the increasing penetration level of renewable energy sources in addition to the growth of new electrical demand sectors, such as electrical vehicles, the power system may face serious problems and challenges in the near future. A revolutionary new power grid system, called smart grid, has been developed as a solution to these problems. The smart grid, equipped with modern communication and computation infrastructures, can coordinate different parts of the power system to enhance energy efficiency, reliability, and quality, while decreasing the energy cost. Since conventional distribution networks lack smart infrastructures, much research has been recently done in the distribution part of the smart grid, called smart distribution grid (SDG. This paper surveys contemporary literature in SDG from the perspective of the electricity market in addition to power system considerations. For this purpose, this paper reviews current demand side management methods, supply side management methods, and electrical vehicle charging and discharging techniques in SDG and also discusses their drawbacks. We also present future research directions to tackle new and existing challenges in the SDG.

Electric industry governance. Reconciling competitive power markets and the physics of complex transmission interconnections

Energy Technology Data Exchange (ETDEWEB)

Stalon, Charles G. [Energy Regulation, Cape Girardeau, MO (United States)

1997-03-01

Creating efficient, competitive power markets in an electric industry composed of interconnected control areas requires the existence of some agency with authority to define, impose and enforce rules for the operation of all control areas so interconnected. It has been noted that `the pursuit of self-interest, unrestrained by suitable institutions, carries no guarantee of anything except chaos`. In no part of the economy is this lesson more relevant than in the North American electric industry. As the industry evolves from one dominated by vertically-integrated utilities into one with competitive power markets and unregulated generators, the system of coordinating institutions that has worked acceptably well to restrain and guide self-interested decision makers of economically regulated firms must now be reconstructed to restrain and guide self-interested decision makers of unregulated generating companies (gencos), power merchants and brokers

Sustainable Power Supply Solutions for Off-Grid Base Stations

Directory of Open Access Journals (Sweden)

Asma Mohamad Aris

2015-09-01

Full Text Available The telecommunication sector plays a significant role in shaping the global economy and the way people share information and knowledge. At present, the telecommunication sector is liable for its energy consumption and the amount of emissions it emits in the environment. In the context of off-grid telecommunication applications, off-grid base stations (BSs are commonly used due to their ability to provide radio coverage over a wide geographic area. However, in the past, the off-grid BSs usually relied on emission-intensive power supply solutions such as diesel generators. In this review paper, various types of solutions (including, in particular, the sustainable solutions for powering BSs are discussed. The key aspects in designing an ideal power supply solution are reviewed, and these mainly include the pre-feasibility study and the thermal management of BSs, which comprise heating and cooling of the BS shelter/cabinets and BS electronic equipment and power supply components. The sizing and optimization approaches used to design the BSs’ power supply systems as well as the operational and control strategies adopted to manage the power supply systems are also reviewed in this paper.

Passivity-Based Stability Assessment of Grid-Connected VSCs - An Overview

DEFF Research Database (Denmark)

Harnefors, Lennart; Wang, Xiongfei; Yepes, Alejandro G.

2016-01-01

The interconnection stability of a grid-connected voltage-source converter (VSC) can be assessed by the passivity properties of the VSC input admittance. If critical grid resonances fall within regions where the input admittance acts passively, i.e., has nonnegative real part, then their destabil......The interconnection stability of a grid-connected voltage-source converter (VSC) can be assessed by the passivity properties of the VSC input admittance. If critical grid resonances fall within regions where the input admittance acts passively, i.e., has nonnegative real part...

Sandia and NJ TRANSIT Authority Developing Resilient Power Grid

Energy Technology Data Exchange (ETDEWEB)

Hanley, Charles J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-11-01

Through the memorandum of understanding between the Depratment of Energy (DOE), the New Jersey Transit Authority (NJ Transit), and the New Jersey Board of Public Utilities, Sandia National Labs is assisting NJ Transit in developing NJ TransitGrid: an electric microgrid that will include a large-scale gas-fired generation facility and distributed energy resources (photovoltaics [PV], energy storage, electric vehicles, combined heat and power [CHP]) to supply reliable power during storms or other times of significant power failure. The NJ TransitGrid was awarded $410M from the Department of Transportation to develop a first-of-its-kind electric microgrid capable of supplying highly-reliable power.

Performance analysis of a grid connected photovoltaic park on the island of Crete

International Nuclear Information System (INIS)

Kymakis, Emmanuel; Kalykakis, Sofoklis; Papazoglou, Thales M.

2009-01-01

The favorable climate conditions of the island of Crete and the recent legislation for utilization of renewable energy sources provide a substantial incentive for installation of photovoltaic power plants. In this paper, the grid connected photovoltaic park of C. Rokas SA in Sitia, Crete, is presented, and its performance is evaluated. The photovoltaic park has a peak power of 171.36 kW p and has been in operation since 2002. The park is suitably monitored during 1 year, and the performance ratio and the various power losses (temperature, soiling, internal, network, power electronics, grid availability and interconnection) are calculated. The PV park supplied 229 MW h to the grid during 2007, ranging from 335.48 to 869.68 kW h. The final yield (Y F ) ranged from 1.96 to 5.07 h/d, and the performance ratio (PR) ranged from 58 to 73%, giving an annual PR of 67.36%

PowerMatching City : A unique smart grid project

NARCIS (Netherlands)

dr. C.J. Wiekens

2014-01-01

In this presentation, the smart grid project 'PowerMatching City' is introduced. PowerMatching City is a living lab demonstration of the future energy system. In PowerMatching City the connected households are equipped with a mix of decentralized energy sources, hybrid heat pumps, smart appliances,

Optimization Strategies for the Vulnerability Analysis of the Electric Power Grid

Energy Technology Data Exchange (ETDEWEB)

Pinar, A.; Meza, J.; Donde, V.; Lesieutre, B.

2007-11-13

Identifying small groups of lines, whose removal would cause a severe blackout, is critical for the secure operation of the electric power grid. We show how power grid vulnerability analysis can be studied as a mixed integer nonlinear programming (MINLP) problem. Our analysis reveals a special structure in the formulation that can be exploited to avoid nonlinearity and approximate the original problem as a pure combinatorial problem. The key new observation behind our analysis is the correspondence between the Jacobian matrix (a representation of the feasibility boundary of the equations that describe the flow of power in the network) and the Laplacian matrix in spectral graph theory (a representation of the graph of the power grid). The reduced combinatorial problem is known as the network inhibition problem, for which we present a mixed integer linear programming formulation. Our experiments on benchmark power grids show that the reduced combinatorial model provides an accurate approximation, to enable vulnerability analyses of real-sized problems with more than 10,000 power lines.

Grid Computing

Indian Academy of Sciences (India)

A computing grid interconnects resources such as high performancecomputers, scientific databases, and computercontrolledscientific instruments of cooperating organizationseach of which is autonomous. It precedes and is quitedifferent from cloud computing, which provides computingresources by vendors to customers ...

Power conditioning unit for photovoltaic power systems

Science.gov (United States)

Beghin, G.; Nguyen Phuoc, V. T.

Operational features and components of a power conditioning unit for interconnecting solar cell module powers with a utility grid are outlined. The two-stage unit first modifies the voltage to desired levels on an internal dc link, then inverts the current in 2 power transformers connected to a vector summation control to neutralize harmonic distortion up to the 11th harmonic. The system operates in parallel with the grid with extra inductors to absorb line-to-line voltage and phase differences, and permits peak power use from the PV array. Reactive power is gained internally, and a power system controller monitors voltages, frequencies, and currents. A booster preregulator adjusts the input voltage from the array to provide voltage regulation for the inverter, and can commutate 450 amps. A total harmonic distortion of less than 5 percent is claimed, with a rating of 5 kVA, 50/60 Hz, 3-phase, and 4-wire.

Model predictive control for power flows in networks with limited capacity

DEFF Research Database (Denmark)

Biegel, Benjamin; Stoustrup, Jakob; Bendtsen, Jan Dimon

2012-01-01

this problem can be formulated as an optimization problem, leading directly to the design of a model predictive controller. Using this scheme, we are able to incorporate predictions of future consumption and exploit knowledge of link limitations such that the intelligent consumers are utilized ahead of time......We consider an interconnected network of consumers powered through an electrical grid of limited capacity. A subset of the consumers are intelligent consumers and have the ability to store energy in a controllable fashion; they can be filled and emptied as desired under power and capacity...... limitations. We address the problem of maintaining power balance between production and consumption using the intelligent consumers to ensure smooth power consumption from the grid. Further, certain capacity limitations to the links interconnecting the consumers must be honored. In this paper, we show how...

Renewable energy off-grid power systems: options for energy suppliers

International Nuclear Information System (INIS)

Trouchet, K.

1992-01-01

SURVIVOR ENERGY SYSTEMS package a range of wind-based renewable energy systems for the supply of 24-hour power to off-grid homesteads and communities. This paper presents a leasing package for these power users and illustrates their cost effectiveness in comparison with stand-alone diesel and comparative hybrid power options. This offer is seen as a alternative for energy planners and supply agencies for their off-grid clients. 6 refs., 3 tabs., 3 figs

Smoothing effect for spatially distributed renewable resources and its impact on power grid robustness.

Science.gov (United States)

Nagata, Motoki; Hirata, Yoshito; Fujiwara, Naoya; Tanaka, Gouhei; Suzuki, Hideyuki; Aihara, Kazuyuki

2017-03-01

In this paper, we show that spatial correlation of renewable energy outputs greatly influences the robustness of the power grids against large fluctuations of the effective power. First, we evaluate the spatial correlation among renewable energy outputs. We find that the spatial correlation of renewable energy outputs depends on the locations, while the influence of the spatial correlation of renewable energy outputs on power grids is not well known. Thus, second, by employing the topology of the power grid in eastern Japan, we analyze the robustness of the power grid with spatial correlation of renewable energy outputs. The analysis is performed by using a realistic differential-algebraic equations model. The results show that the spatial correlation of the energy resources strongly degrades the robustness of the power grid. Our results suggest that we should consider the spatial correlation of the renewable energy outputs when estimating the stability of power grids.

General Forced Oscillations in a Real Power Grid Integrated with Large Scale Wind Power

Directory of Open Access Journals (Sweden)

Ping Ju

2016-07-01

Full Text Available According to the monitoring of the wide area measurement system, inter-area oscillations happen more and more frequently in a real power grid of China, which are close to the forced oscillation. Applying the conventional forced oscillation theory, the mechanism of these oscillations cannot be explained well, because the oscillations vary with random amplitude and a narrow frequency band. To explain the mechanism of such oscillations, the general forced oscillation (GFO mechanism is taken into consideration. The GFO is the power system oscillation excited by the random excitations, such as power fluctuations from renewable power generation. Firstly, properties of the oscillations observed in the real power grid are analyzed. Using the GFO mechanism, the observed oscillations seem to be the GFO caused by some random excitation. Then the variation of the wind power measured in this power gird is found to be the random excitation which may cause the GFO phenomenon. Finally, simulations are carried out and the power spectral density of the simulated oscillation is compared to that of the observed oscillation, and they are similar with each other. The observed oscillation is thus explained well using the GFO mechanism and the GFO phenomenon has now been observed for the first time in real power grids.

Interconnecting PV on New York City's Secondary Network Distribution System

Energy Technology Data Exchange (ETDEWEB)

Anderson, K; Coddington, M; Burman, K; Hayter, S; Kroposki, B; Watson, and A

2009-11-01

The U.S. Department of Energy (DOE) has teamed with cities across the country through the Solar America Cities (SAC) partnership program to help reduce barriers and accelerate implementation of solar energy. The New York City SAC team is a partnership between the City University of New York (CUNY), the New York City Mayor s Office of Long-term Planning and Sustainability, and the New York City Economic Development Corporation (NYCEDC).The New York City SAC team is working with DOE s National Renewable Energy Laboratory (NREL) and Con Edison, the local utility, to develop a roadmap for photovoltaic (PV) installations in the five boroughs. The city set a goal to increase its installed PV capacity from1.1 MW in 2005 to 8.1 MW by 2015 (the maximum allowed in 2005). A key barrier to reaching this goal, however, is the complexity of the interconnection process with the local utility. Unique challenges are associated with connecting distributed PV systems to secondary network distribution systems (simplified to networks in this report). Although most areas of the country use simpler radial distribution systems to distribute electricity, larger metropolitan areas like New York City typically use networks to increase reliability in large load centers. Unlike the radial distribution system, where each customer receives power through a single line, a network uses a grid of interconnected lines to deliver power to each customer through several parallel circuits and sources. This redundancy improves reliability, but it also requires more complicated coordination and protection schemes that can be disrupted by energy exported from distributed PV systems. Currently, Con Edison studies each potential PV system in New York City to evaluate the system s impact on the network, but this is time consuming for utility engineers and may delay the customer s project or add cost for larger installations. City leaders would like to streamline this process to facilitate faster, simpler, and

Operation Performance Evaluation of Power Grid Enterprise Using a Hybrid BWM-TOPSIS Method

Directory of Open Access Journals (Sweden)

Peipei You

2017-12-01

Full Text Available Electricity market reform is in progress in China, and the operational performance of power grid enterprises are vital for its healthy and sustainable development in the current electricity market environment. In this paper, a hybrid multi-criteria decision-making (MCDM framework for operational performance evaluation of a power grid enterprise is proposed from the perspective of sustainability. The latest MCDM method, namely the best-worst method (BWM was employed to determine the weights of all criteria, and the technique for order preference by similarity to an ideal solution (TOPSIS was applied to rank the operation performance of a power grid enterprise. The evaluation index system was built based on the concept of sustainability, which includes three criteria (namely economy, society, and environment and seven sub-criteria. Four power grid enterprises were selected to perform the empirical analysis, and the results indicate that power grid enterprise A1 has the best operation performance. The proposed hybrid BWM-TOPSIS-based framework for operation performance evaluation of a power grid enterprise is effective and practical.

Wide-area situation awareness in electric power grid

Science.gov (United States)

Greitzer, Frank L.

2010-04-01

Two primary elements of the US energy policy are demand management and efficiency and renewable sources. Major objectives are clean energy transmission and integration, reliable energy transmission, and grid cyber security. Development of the Smart Grid seeks to achieve these goals by lowering energy costs for consumers, achieving energy independence and reducing greenhouse gas emissions. The Smart Grid is expected to enable real time wide-area situation awareness (SA) for operators. Requirements for wide-area SA have been identified among interoperability standards proposed by the Federal Energy Regulatory Commission and the National Institute of Standards and Technology to ensure smart-grid functionality. Wide-area SA and enhanced decision support and visualization tools are key elements in the transformation to the Smart Grid. This paper discusses human factors research to promote SA in the electric power grid and the Smart Grid. Topics that will be discussed include the role of human factors in meeting US energy policy goals, the impact and challenges for Smart Grid development, and cyber security challenges.

Harmonizing electricity markets with physics : real time performance monitoring using grid-3PTM

International Nuclear Information System (INIS)

Budhraja, V.S.

2003-01-01

The Electric Power Group, LLC provides management and strategic consulting services for the electric power industry, with special emphasis on industry restructuring, competitive electricity markets, grid operations and reliability, power technologies, venture investments and start-ups. The Consortium for Electric Reliability Technology Solutions involves national laboratories, universities, and industry partners in researching, developing, and commercializing electric reliability technology solutions to protect and enhance the reliability of the American electric power system under the emerging competitive electricity market structure. Physics differentiate electric markets from other markets: there is real-time balancing, no storage, interconnected network, and power flows governed by physics. Some issues affecting both grid reliability and market issues are difficult to separate, such as security and congestion management, voltage management, reserves, frequency volatility, and others. The author examined the following investment challenges facing the electricity market: grid solutions, market solutions, and technology solutions. The real time performance monitoring and prediction platform, grid-3P was described and applications discussed, such as ACE-frequency monitoring, performance monitoring for automatic generation control (AGC) and frequency response, voltage/VAR monitoring, stability monitoring using phasor technology, and market monitoring. figs

Multi-Megawatt-Scale Power-Hardware-in-the-Loop Interface for Testing Ancillary Grid Services by Converter-Coupled Generation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Koralewicz, Przemyslaw J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wallen, Robert B [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-07-26

Power-hardware-in-the-loop (PHIL) is a simulation tool that can support electrical systems engineers in the development and experimental validation of novel, advanced control schemes that ensure the robustness and resiliency of electrical grids that have high penetrations of low-inertia variable renewable resources. With PHIL, the impact of the device under test on a generation or distribution system can be analyzed using a real-time simulator (RTS). PHIL allows for the interconnection of the RTS with a 7 megavolt ampere (MVA) power amplifier to test multi-megawatt renewable assets available at the National Wind Technology Center (NWTC). This paper addresses issues related to the development of a PHIL interface that allows testing hardware devices at actual scale. In particular, the novel PHIL interface algorithm and high-speed digital interface, which minimize the critical loop delay, are discussed.

Stability of synchrony against local intermittent fluctuations in tree-like power grids

Science.gov (United States)

Auer, Sabine; Hellmann, Frank; Krause, Marie; Kurths, Jürgen

2017-12-01

90% of all Renewable Energy Power in Germany is installed in tree-like distribution grids. Intermittent power fluctuations from such sources introduce new dynamics into the lower grid layers. At the same time, distributed resources will have to contribute to stabilize the grid against these fluctuations in the future. In this paper, we model a system of distributed resources as oscillators on a tree-like, lossy power grid and its ability to withstand desynchronization from localized intermittent renewable infeed. We find a remarkable interplay of the network structure and the position of the node at which the fluctuations are fed in. An important precondition for our findings is the presence of losses in distribution grids. Then, the most network central node splits the network into branches with different influence on network stability. Troublemakers, i.e., nodes at which fluctuations are especially exciting the grid, tend to be downstream branches with high net power outflow. For low coupling strength, we also find branches of nodes vulnerable to fluctuations anywhere in the network. These network regions can be predicted at high confidence using an eigenvector based network measure taking the turbulent nature of perturbations into account. While we focus here on tree-like networks, the observed effects also appear, albeit less pronounced, for weakly meshed grids. On the other hand, the observed effects disappear for lossless power grids often studied in the complex system literature.

Power Loss Analysis for Wind Power Grid Integration Based on Weibull Distribution

Directory of Open Access Journals (Sweden)

Ahmed Al Ameri

2017-04-01

Full Text Available The growth of electrical demand increases the need of renewable energy sources, such as wind energy, to meet that need. Electrical power losses are an important factor when wind farm location and size are selected. The capitalized cost of constant power losses during the life of a wind farm will continue to high levels. During the operation period, a method to determine if the losses meet the requirements of the design is significantly needed. This article presents a Simulink simulation of wind farm integration into the grid; the aim is to achieve a better understanding of wind variation impact on grid losses. The real power losses are set as a function of the annual variation, considering a Weibull distribution. An analytical method has been used to select the size and placement of a wind farm, taking into account active power loss reduction. It proposes a fast linear model estimation to find the optimal capacity of a wind farm based on DC power flow and graph theory. The results show that the analytical approach is capable of predicting the optimal size and location of wind turbines. Furthermore, it revealed that the annual variation of wind speed could have a strong effect on real power loss calculations. In addition to helping to improve utility efficiency, the proposed method can develop specific designs to speeding up integration of wind farms into grids.

National Assessment of Energy Storage for Grid Balancing and Arbitrage: Phase 1, WECC

Energy Technology Data Exchange (ETDEWEB)

Kintner-Meyer, Michael CW; Balducci, Patrick J.; Colella, Whitney G.; Elizondo, Marcelo A.; Jin, Chunlian; Nguyen, Tony B.; Viswanathan, Vilayanur V.; Zhang, Yu

2012-06-01

To examine the role that energy storage could play in mitigating the impacts of the stochastic variability of wind generation on regional grid operation, the Pacific Northwest National Laboratory (PNNL) examined a hypothetical 2020 grid scenario in which additional wind generation capacity is built to meet renewable portfolio standard targets in the Western Interconnection. PNNL developed a stochastic model for estimating the balancing requirements using historical wind statistics and forecasting error, a detailed engineering model to analyze the dispatch of energy storage and fast-ramping generation devices for estimating size requirements of energy storage and generation systems for meeting new balancing requirements, and financial models for estimating the life-cycle cost of storage and generation systems in addressing the future balancing requirements for sub-regions in the Western Interconnection. Evaluated technologies include combustion turbines, sodium sulfur (Na-S) batteries, lithium ion batteries, pumped-hydro energy storage, compressed air energy storage, flywheels, redox flow batteries, and demand response. Distinct power and energy capacity requirements were estimated for each technology option, and battery size was optimized to minimize costs. Modeling results indicate that in a future power grid with high-penetration of renewables, the most cost competitive technologies for meeting balancing requirements include Na-S batteries and flywheels.

Research on a New Control Scheme of Photovoltaic Grid Power Generation System

Directory of Open Access Journals (Sweden)

Dong-Hui Li

2014-01-01

Full Text Available A new type of photovoltaic grid power generation system control scheme to solve the problems of the conventional photovoltaic grid power generation systems is presented. To aim at the oscillation and misjudgment of traditional perturbation observation method, an improved perturbation observation method comparing to the next moment power is proposed, combining with BOOST step-up circuit to realize the maximum power tracking. To counter the harmonic pollution problem in photovoltaic grid power generation system, the deadbeat control scheme in fundamental wave synchronous frequency rotating coordinate system of power grid is presented. A parameter optimization scheme based on positive feedback of active frequency shift island detection to solve the problems like the nondetection zone due to the import of disturbance in traditional island detection method is proposed. Finally, the results in simulation environment by MATLAB/Simulink simulation and experiment environment verify the validity and superiority of the proposed scheme.

National energy policy provides scant power direction. [Canada

Energy Technology Data Exchange (ETDEWEB)

1976-05-07

More federal direction on electric power developments was expected than actually materialized in the national energy policy released recently by Energy, Mines, and Resources. None of the primary objectives was specifically geared to improving the sagging power outlook. The five targets mentioned would have varying positive influences on Canadian power security if achieved, but oil and gas problems stole the spotlight. Failure of a national energy grid to make the top priority list was a disappointment. Observers had been expecting more prominent treatment for grid schemes in light of comments made by energy minister Alastair Gillespie at the recent energy conservation conference in Ottawa. But the strategy paper merely endorses the strengthening of regional interconnections, particularly in eastern Canada, and urges closer coordination among provincial utilities in planning and development. It reveals no new move to spur grid action and only reiterates the federal offer to back 50 percent of interconnection studies and capital costs. The paper does recognize that strengthened regional ties would lead to a form of integrated national system permitting more efficient systems growth, mutual assistance in the event of power failures, and some averaging out of peak and off-peak loads. They would economize on the need for stand-by power and enhance more rational expansion.

Distributed maximum power point tracking in wind micro-grids

Directory of Open Access Journals (Sweden)

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.

Utilization of graph theory in security analysis of power grid

Directory of Open Access Journals (Sweden)

Dalibor Válek

2014-12-01

Full Text Available This paper describes way how to use graph theory in security analysis. As an environment is used network of power lines and devices which are included here. Power grid is considered as a system of nodes which make together graph (network. On the simple example is applied Fiedler´s theory which is able to select the most important power lines of whole network. Components related to these lines are logicly ordered and considered by author´s modified analysis. This method has been improved and optimalized for risks related with illegal acts. Each power grid component has been connected with possible kind of attack and every of this device was gradually evaluated by five coefficients which takes values from 1 to 10. On the coefficient basis was assessed the level of risk. In the last phase the most risky power grid components have been selected. On the selected devices have been proposed security measures.

Impact of wind power plant reactive current injection during asymmetrical grid faults

DEFF Research Database (Denmark)

Göksu, Ömer; Teodorescu, Remus; Bak, Claus Leth

2013-01-01

As more renewable energy sources, especially more wind turbines (WTs) are installed in the power system; grid codes for wind power integration are being generated to sustain stable power system operation with non-synchronous generation. Common to most of the grid codes, wind power plants (WPPs...... faults, is investigated, which was not considered in the wind power impact studies before....

An Efficient Topology-Based Algorithm for Transient Analysis of Power Grid

KAUST Repository

Yang, Lan

2015-08-10

In the design flow of integrated circuits, chip-level verification is an important step that sanity checks the performance is as expected. Power grid verification is one of the most expensive and time-consuming steps of chip-level verification, due to its extremely large size. Efficient power grid analysis technology is highly demanded as it saves computing resources and enables faster iteration. In this paper, a topology-base power grid transient analysis algorithm is proposed. Nodal analysis is adopted to analyze the topology which is mathematically equivalent to iteratively solving a positive semi-definite linear equation. The convergence of the method is proved.

Renewable Electricity-to-Grid Integration | Energy Systems Integration

Science.gov (United States)

Facility | NREL Renewable Electricity-to-Grid Integration Renewable Electricity-to-Grid Integration NREL works with industry partners to optimize strategies for effectively interconnecting renewable renewable electric grid integration work includes research and development (R&D) on advanced inverters

Designing Wind and Solar Power Purchase Agreements to Support Grid Integration

Energy Technology Data Exchange (ETDEWEB)

O' Neill, Barbara [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chernyakhovskiy, Ilya [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-07-01

Power purchase agreements (PPAs) represent one of many institutional tools that power systems can use to improve grid services from variable renewable energy (VRE) generators. This fact sheet introduces the concept of PPAs for VRE generators and provides a brief summary of key PPA components that can facilitate VRE generators to enhance grid stability and serve as a source of power system flexibility.

Grid Integration Science, NREL Power Systems Engineering Center

Energy Technology Data Exchange (ETDEWEB)

Kroposki, Benjamin [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-04-25

This report highlights journal articles published in 2016 by researchers in the Power Systems Engineering Center. NREL's Power Systems Engineering Center published 47 journal and magazine articles in the past year, highlighting recent research in grid modernization.

Multiresonant Frequency-Locked Loop for Grid Synchronization of Power Converters Under Distorted Grid Conditions

DEFF Research Database (Denmark)

Rodriguez, Pedro; Luna, Alvaro; Candela, Ignacio

2011-01-01

This paper presents a new multiresonant frequency-adaptive synchronization method for grid-connected power converters that allows estimating not only the positive- and negative-sequence components of the power signal at the fundamental frequency but also other sequence components at other harmoni...

Power system SCADA and smart grids

CERN Document Server

Thomas, Mini S

2015-01-01

Power System SCADA and Smart Grids brings together in one concise volume the fundamentals and possible application functions of power system supervisory control and data acquisition (SCADA). The text begins by providing an overview of SCADA systems, evolution, and use in power systems and the data acquisition process. It then describes the components of SCADA systems, from the legacy remote terminal units (RTUs) to the latest intelligent electronic devices (IEDs), data concentrators, and master stations, as well as:Examines the building and practical implementation of different SCADA systemsOf

Modelling and Simulation of Grid Connected SPV System with Active Power Filtering Features

Science.gov (United States)

Saroha, Jaipal; Pandove, Gitanjali; Singh, Mukhtiar

2017-09-01

In this paper, the detailed simulation studies for a grid connected solar photovoltaic system (SPV) have been presented. The power electronics devices like DC-DC boost converter and grid interfacing inverter are most important components of proposed system. Here, the DC-DC boost converter is controlled to extract maximum power out of SPV under different irradiation levels, while the grid interfacing inverter is utilized to evacuate the active power and feed it into grid at synchronized voltage and frequency. Moreover, the grid interfacing inverter is also controlled to sort out the issues related to power quality by compensating the reactive power and harmonics current component of nearby load at point of common coupling. Besides, detailed modeling of various component utilized in proposed system is also presented. Finally, extensive simulations have been performed under different irradiation levels with various kinds of load to validate the aforementioned claims. The overall system design and simulation have been performed by using Sim Power System toolbox available in the library of MATLAB.

Power quality and integration of wind farms in weak grids in India

Energy Technology Data Exchange (ETDEWEB)

Soerensen, P.; Hauge Madsen, P. [Risoe National Lab., Roskilde (Denmark). Wind Energy and Atmospheric Physics Dept.; Vikkelsoe, A.; Koelbaek Jensen, K. [Danske Elvaerkers Forening Udredningsafdelingen (DEFU), Lyngby (Denmark); Fathima, K.A.; Unnikrishnan, A.K.

2000-04-01

This is the final report of a joint Danish and Indian project' Power Quality and Integration of Wind Farms in Weak Grids'. The power quality issues have been studied and analysed with the Indian conditions as a case. On the basis of meetings with Danish wind turbine industry, Indian electricity boards, nodal agencies, wind turbine industry and authorities, the critical power quality as-pects in India have been identified. Measurements on selected wind farms and wind turbines have quantified the power quality, and analyses of power quality issues, especially reactive power compensation, have been performed. Based on measurements and analyses, preliminary recommendations for grid integration of wind turbines in weak grids have been formulated. (au)

Proceedings of scientific-technical seminar: materials investigation for power stations and power grid

International Nuclear Information System (INIS)

1994-05-01

This report is an assembly of the papers concerning the material problems occurring during the exploitation of power stations as well as power grid. The diagnostic methods are also discussed. (author)

Comparative analysis of the application of different Low Power Wide Area Network technologies in power grid

Science.gov (United States)

Wang, Hao; Sui, Hong; Liao, Xing; Li, Junhao

2018-03-01

Low Power Wide Area Network (LPWAN) technologies developed rapidly in recent years, but the application principle of different LPWAN technologies in power grid is still not clear. This paper gives a comparative analysis of two mainstream LPWAN technologies including NB-IoT and LoRa, and gives an application suggestion of these two LPWAN technologies, which can guide the planning and construction of LPWAN in power grid.

Hybrid AC-High Voltage DC Grid Stability and Controls

Science.gov (United States)

Yu, Jicheng

The growth of energy demands in recent years has been increasing faster than the expansion of transmission facility construction. This tendency cooperating with the continuous investing on the renewable energy resources drives the research, development, and construction of HVDC projects to create a more reliable, affordable, and environmentally friendly power grid. Constructing the hybrid AC-HVDC grid is a significant move in the development of the HVDC techniques; the form of dc system is evolving from the point-to-point stand-alone dc links to the embedded HVDC system and the multi-terminal HVDC (MTDC) system. The MTDC is a solution for the renewable energy interconnections, and the MTDC grids can improve the power system reliability, flexibility in economic dispatches, and converter/cable utilizing efficiencies. The dissertation reviews the HVDC technologies, discusses the stability issues regarding the ac and HVDC connections, proposes a novel power oscillation control strategy to improve system stability, and develops a nonlinear voltage droop control strategy for the MTDC grid. To verify the effectiveness the proposed power oscillation control strategy, a long distance paralleled AC-HVDC transmission test system is employed. Based on the PSCAD/EMTDC platform simulation results, the proposed power oscillation control strategy can improve the system dynamic performance and attenuate the power oscillations effectively. To validate the nonlinear voltage droop control strategy, three droop controls schemes are designed according to the proposed nonlinear voltage droop control design procedures. These control schemes are tested in a hybrid AC-MTDC system. The hybrid AC-MTDC system, which is first proposed in this dissertation, consists of two ac grids, two wind farms and a five-terminal HVDC grid connecting them. Simulation studies are performed in the PSCAD/EMTDC platform. According to the simulation results, all the three design schemes have their unique salient

Online Detection and Estimation of Grid Impedance Variation for Distributed Power Generation

DEFF Research Database (Denmark)

Jebali-Ben Ghorbal, Manel; Ghzaiel, Walid; Slama-Belkhodja, Ilhem

2012-01-01

A better knowledge of the grid impedance is essential in order to improve power quality and control of the Distributed Power Generation Systems (DPGS) and also for a safe connection or reconnection to the utility grid. An LCL-filter associated to a Voltage Source Inverter (VSI) is usually used...... to disconnect the DPG systems of the network. This work presents a rapid and simple technique to detect the grid impedance variation and to determine the grid impedance before and after grid faults accurs. Implementation on FPGA control board, simulations and experimental results are presented to validate...

An evaluation method of power quality about electrified railways connected to power grid based on PSCAD/EMTDC

Science.gov (United States)

Liang, Weibin; Ouyang, Sen; Huang, Xiang; Su, Weijian

2017-05-01

The existing modeling process of power quality about electrified railways connected to power grid is complicated and the simulation scene is incomplete, so this paper puts forward a novel evaluation method of power quality based on PSCAD/ETMDC. Firstly, a model of power quality about electrified railways connected to power grid is established, which is based on testing report or measured data. The equivalent model of electrified locomotive contains power characteristic and harmonic characteristic, which are substituted by load and harmonic source. Secondly, in order to make evaluation more complete, an analysis scheme has been put forward. The scheme uses a combination of three-dimensions of electrified locomotive, which contains types, working conditions and quantity. At last, Shenmao Railway is taken as example to evaluate the power quality at different scenes, and the result shows electrified railways connected to power grid have significant effect on power quality.

Fuzzy-predictive direct power control implementation of a grid connected photovoltaic system, associated with an active power filter

International Nuclear Information System (INIS)

Ouchen, Sabir; Betka, Achour; Abdeddaim, Sabrina; Menadi, Abdelkrim

2016-01-01

Highlights: • An implementation on dSPACE 1104 of a double stage grid connected photovoltaic system, associated with an active power filter. • A fuzzy logic controller for maximum power point tracking of photovoltaic generator using a boost converter. • Predictive direct power control almost eliminates the effect of harmonics under a unite power factor. • The robustness of control strategies was examined in different irradiance level conditions. - Abstract: The present paper proposes a real time implementation of an optimal operation of a double stage grid connected photovoltaic system, associated with a shunt active power filter. On the photovoltaic side, a fuzzy logic based maximum power point taking control is proposed to track permanently the optimum point through an adequate tuning of a boost converter regardless the solar irradiance variations; whereas, on the grid side, a model predictive direct power control is applied, to ensure both supplying a part of the load demand with the extracted photovoltaic power, and a compensation of undesirable harmonic contents of the grid current, under a unity power factor operation. The implementation of the control strategies is conducted on a small scale photovoltaic system, controlled via a dSPACE 1104 single card. The obtained experimental results show on one hand, that the proposed Fuzzy logic based maximum power taking point technique provides fast and high performances under different irradiance levels while compared with a sliding mode control, and ensures 1.57% more in efficiency. On the other hand, the predictive power control ensures a flexible settlement of active power amounts exchanges with the grid, under a unity power functioning. Furthermore, the grid current presents a sinusoidal shape with a tolerable total harmonic distortion coefficient 4.71%.

Benchmarking of Constant Power Generation Strategies for Single-Phase Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

With a still increase of grid-connected Photovoltaic (PV) systems, challenges have been imposed on the grid due to the continuous injection of a large amount of fluctuating PV power, like overloading the grid infrastructure (e.g., transformers) during peak power production periods. Hence, advanced...

Robust Control of Wide Bandgap Power Electronics Device Enabled Smart Grid

Science.gov (United States)

Yao, Tong

In recent years, wide bandgap (WBG) devices enable power converters with higher power density and higher efficiency. On the other hand, smart grid technologies are getting mature due to new battery technology and computer technology. In the near future, the two technologies will form the next generation of smart grid enabled by WBG devices. This dissertation deals with two applications: silicon carbide (SiC) device used for medium voltage level interface (7.2 kV to 240 V) and gallium nitride (GaN) device used for low voltage level interface (240 V/120 V). A 20 kW solid state transformer (SST) is designed with 6 kHz switching frequency SiC rectifier. Then three robust control design methods are proposed for each of its smart grid operation modes. In grid connected mode, a new LCL filter design method is proposed considering grid voltage THD, grid current THD and current regulation loop robust stability with respect to the grid impedance change. In grid islanded mode, micro synthesis method combined with variable structure control is used to design a robust controller for grid voltage regulation. For grid emergency mode, multivariable controller designed using Hinfinity synthesis method is proposed for accurate power sharing. Controller-hardware-in-the-loop (CHIL) testbed considering 7-SST system is setup with Real Time Digital Simulator (RTDS). The real TMS320F28335 DSP and Spartan 6 FPGA control board is used to interface a switching model SST in RTDS. And the proposed control methods are tested. For low voltage level application, a 3.3 kW smart grid hardware is built with 3 GaN inverters. The inverters are designed with the GaN device characterized using the proposed multi-function double pulse tester. The inverter is controlled by onboard TMS320F28379D dual core DSP with 200 kHz sampling frequency. Each inverter is tested to process 2.2 kW power with overall efficiency of 96.5 % at room temperature. The smart grid monitor system and fault interrupt devices (FID

Protections Against Grid Breakdowns in the ITER Neutral Beam Injector Power Supplies

International Nuclear Information System (INIS)

Bigi, M.; Toigo, V.; Zanotto, L.

2006-01-01

The ITER Neutral Beam Injector (NBI) is designed to deliver 16.5 MW of additional heating power to the plasma, accelerating negative ions up to -1 MV with a current up to 40 A. Two main power supplies are foreseen to feed the system: the Acceleration Grid Power Supply (AGPS), which provides power to the acceleration grids, and the Ion Source Power Supply (ISPS), devoted to supplying the ion source components. For the accelerator, two different concepts are under investigation: the MAMuG (Multiple Aperture, Multiple Gap) and the SINGAP (SINgle Aperture). During operation of the NBI, the breakdown of the acceleration grids will occur regularly; as a consequence the AGPS is expected to experience frequent load short-circuits during a pulse. For each grid breakdown, energy and current peaks are delivered from the power supply systems that could damage the grids, if not limited. In previous NBI, rated for a lower accelerating voltage, the protection system in case of grid breakdowns was based on dc circuit breakers able to quickly disconnect the power supply from the grids. In the ITER case, a similar solution is not feasible, as the voltage level is too high for present dc breaker technology. Therefore, the protection strategy has to rely on fast switch-off of the power supplies, on the optimisation of the filter elements and core snubbers placed downstream the AGPS and on the introduction of additional passive elements. However, achieving a satisfactory protection against grid breakdowns is a challenging task, as the optimisation of each single provision can result in drawbacks for other aspects of the design; for instance, the optimisation of the filter elements, obtained by reducing the filter capacitance, produces an increase of the output voltage ripple. Therefore, the design of the protections must be carried out considering all the relevant aspects of the specifications, also those that are not strictly related to the limitations of the current peaks and energy

Shapley Value-Based Payment Calculation for Energy Exchange between Micro- and Utility Grids

Directory of Open Access Journals (Sweden)

Robin Pilling

2017-10-01

Full Text Available In recent years, microgrids have developed as important parts of power systems and have provided affordable, reliable, and sustainable supplies of electricity. Each microgrid is managed as a single controllable entity with respect to the existing power system but demands for joint operation and sharing the benefits between a microgrid and its hosting utility. This paper is focused on the joint operation of a microgrid and its hosting utility, which cooperatively minimize daily generation costs through energy exchange, and presents a payment calculation scheme for power transactions based on a fair allocation of reduced generation costs. To fairly compensate for energy exchange between the micro- and utility grids, we adopt the cooperative game theoretic solution concept of Shapley value. We design a case study for a fictitious interconnection model between the Mueller microgrid in Austin, Texas and the utility grid in Taiwan. Our case study shows that when compared to standalone generations, both the micro- and utility grids are better off when they collaborate in power exchange regardless of their individual contributions to the power exchange coalition.

Thermal analysis of two-level wind power converter under symmetrical grid fault

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2013-01-01

In this paper, the case of symmetrical grid fault when using the multi-MW wind turbine of partial-scale and full-scale two-level power converter are designed and investigated. Firstly, the different operation behaviors of the relevant power converters under the voltage dip will be described......) condition as well as the junction temperature. For the full-scale wind turbine system, the most thermal stressed power device in the grid-side converter will appear at the grid voltage below 0.5 pu, and for the partial-scale wind turbine system, the most thermal stressed power device in the rotor...

Power control for wind turbines in weak grids: Project summary

DEFF Research Database (Denmark)

Bindner, H.

1999-01-01

. The two case studies (Madeira, Portugal and Co. Donegal, Ireland) revealed that sometimes theleast cost and most attractive option is change in the operating strategy of the power system. This allowed that further wind energy can be integrated at competitive cost in the Madeira power system. In Co....... Donegal the options for pumped storage are goodcombined with good wind resources. Unfortunately the grid is weak. The least cost option for the feeder studied is either grid reinforcement or a power control system based on pumped storage if rather large amounts of wind energy are to be absorbed...... by thepower system. The cost estimates for the two options are in the same range. The current report is a summary of the work done in the project 'Power Control for Wind Turbines in Weak Grids'. The project has been partly funded by EU under contractJOR3-CT95-0067....

IT-Enabled Integration of Renewables: A Concept for the Smart Power Grid

Directory of Open Access Journals (Sweden)

Sauter Thilo

2011-01-01

Full Text Available The wide utilisation of information and communication technologies is hoped to enable a more efficient and sustainable operation of electric power grids. This paper analyses the benefits of smart power grids for the integration of renewable energy resources into the existing grid infrastructure. Therefore, the concept of a smart power grid is analysed, and it is shown that it covers more than for example, time-of-use energy tariffs. Further, the communication technologies used for smart grids are discussed, and the challenge of interoperability between the smart grid itself and its active contributors such as functional buildings is shown. A significant share of electrical energy demand is and will be constituted by large functional buildings that are mostly equipped with automation systems and therefore enable a relatively simple IT integration into smart grids. This large potential of thermal storages and flexible consumption processes might be a future key to match demand and supply under the presence of a high share of fluctuating generation from renewables.

The GRID seminar

CERN Multimedia

CERN. Geneva HR-RFA

2006-01-01

The Grid infrastructure is a key part of the computing environment for the simulation, processing and analysis of the data of the LHC experiments. These experiments depend on the availability of a worldwide Grid infrastructure in several aspects of their computing model. The Grid middleware will hide much of the complexity of this environment to the user, organizing all the resources in a coherent virtual computer center. The general description of the elements of the Grid, their interconnections and their use by the experiments will be exposed in this talk. The computational and storage capability of the Grid is attracting other research communities beyond the high energy physics. Examples of these applications will be also exposed during the presentation.

Integration of Vehicle-to-Grid in Western Danish Power System

DEFF Research Database (Denmark)

Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

2011-01-01

capabilities of large power plants in the future, demands for new balancing solutions like Vehicle-to-Grid systems. In this article, aggregated electric vehicle based battery storage representing a Vehicle-to-Grid system is modelled for the use in long term dynamic power system simulations. Further...... Transmission) control areas are significantly minimized by the faster up and down regulation characteristics of the electric vehicle battery storage....

Allocation of synchronous condensers for restoration of system short-circuit power

DEFF Research Database (Denmark)

Marrazi, Emanuel; Yang, Guangya; Weinreich-Jensen, Peter

2017-01-01

Modern power systems, employing an increasing number of converter-based renewable energy sources (RES) and decreasing the usage of conventional power plants, are leading to lower levels of short-circuit power and rotational inertia. A solution to this is the employment of synchronous condensers...... in the grid, in order to provide sufficient short-circuit power. This results in the increase of the short-circuit ratio (SCR) at transmission system bus-bars serving as points of interconnection (POI) to renewable generation. Evaluation of the required capacity and grid-location of the synchronous condensers...... by renewable generation. Total cost of synchronous condenser installations in the system is minimized and the SCRs at the POIs of central renewable power plants are strengthened. The method has potential for application on larger grids, aiding grid-integration of RES....

Study on optimal configuration of the grid-connected wind-solar-battery hybrid power system

Science.gov (United States)

Ma, Gang; Xu, Guchao; Ju, Rong; Wu, Tiantian

2017-08-01

The capacity allocation of each energy unit in the grid-connected wind-solar-battery hybrid power system is a significant segment in system design. In this paper, taking power grid dispatching into account, the research priorities are as follows: (1) We establish the mathematic models of each energy unit in the hybrid power system. (2) Based on dispatching of the power grid, energy surplus rate, system energy volatility and total cost, we establish the evaluation system for the wind-solar-battery power system and use a number of different devices as the constraint condition. (3) Based on an improved Genetic algorithm, we put forward a multi-objective optimisation algorithm to solve the optimal configuration problem in the hybrid power system, so we can achieve the high efficiency and economy of the grid-connected hybrid power system. The simulation result shows that the grid-connected wind-solar-battery hybrid power system has a higher comprehensive performance; the method of optimal configuration in this paper is useful and reasonable.

Non-Gaussian power grid frequency fluctuations characterized by Lévy-stable laws and superstatistics

Science.gov (United States)

Schäfer, Benjamin; Beck, Christian; Aihara, Kazuyuki; Witthaut, Dirk; Timme, Marc

2018-02-01

Multiple types of fluctuations impact the collective dynamics of power grids and thus challenge their robust operation. Fluctuations result from processes as different as dynamically changing demands, energy trading and an increasing share of renewable power feed-in. Here we analyse principles underlying the dynamics and statistics of power grid frequency fluctuations. Considering frequency time series for a range of power grids, including grids in North America, Japan and Europe, we find a strong deviation from Gaussianity best described as Lévy-stable and q-Gaussian distributions. We present a coarse framework to analytically characterize the impact of arbitrary noise distributions, as well as a superstatistical approach that systematically interprets heavy tails and skewed distributions. We identify energy trading as a substantial contribution to today's frequency fluctuations and effective damping of the grid as a controlling factor enabling reduction of fluctuation risks, with enhanced effects for small power grids.

Multi-net optimization of VLSI interconnect

CERN Document Server

Moiseev, Konstantin; Wimer, Shmuel

2015-01-01

This book covers layout design and layout migration methodologies for optimizing multi-net wire structures in advanced VLSI interconnects. Scaling-dependent models for interconnect power, interconnect delay and crosstalk noise are covered in depth, and several design optimization problems are addressed, such as minimization of interconnect power under delay constraints, or design for minimal delay in wire bundles within a given routing area. A handy reference or a guide for design methodologies and layout automation techniques, this book provides a foundation for physical design challenges of interconnect in advanced integrated circuits.  • Describes the evolution of interconnect scaling and provides new techniques for layout migration and optimization, focusing on multi-net optimization; • Presents research results that provide a level of design optimization which does not exist in commercially-available design automation software tools; • Includes mathematical properties and conditions for optimal...

Overview of Recent Grid Codes for Wind Power Integration

DEFF Research Database (Denmark)

Altin, Müfit; Göksu, Ömer; Teodorescu, Remus

2010-01-01

As wind power penetration level increases, power system operators are challenged by the penetration impacts to maintain reliability and stability of power system. Therefore, grid codes are being published and continuously updated by transmission system operators of the countries. In this paper...

Performance Analysis of 14 MW Grid-Connected Photovoltaic System

International Nuclear Information System (INIS)

Kagilik, Ahmed S.; Tawel, Abduraouf M.

2015-01-01

Many Libyan authorities proposed to investigate the possibility of utilizing a suitable terrain in Libya to add generation capacity of large-scale photovoltaic power plants. In this paper, the first grid-connected PV plant of 14 MWp which will be executed in Hoon city and supported by the Renewable Energy Authority of Libya (REAOL) is presented. To understand and improve the operational behavior of PV system, a comprehensive study including the plant design and detailed performance analysis under a local climate conditions is performed. Using polycrystalline silicon technology, the first year energy yield is estimated and the monthly system output for this plant is calculated. The performance ratio and various power losses (temperature, irradiance, power electronics, interconnection, etc.) are determined. The PV system supplied 24964 MWh to the grid during the first year giving an average annual overall yield factor 1783 kWh/kWp and average annual performance ratio of the system of 76.9%.(author)

Optimal Coordinated EV Charging with Reactive Power Support in Constrained Distribution Grids

Energy Technology Data Exchange (ETDEWEB)

Paudyal, Sumit; Ceylan, Oğuzhan; Bhattarai, Bishnu P.; Myers, Kurt S.

2017-07-01

Electric vehicle (EV) charging/discharging can take place in any P-Q quadrants, which means EVs could support reactive power to the grid while charging the battery. In controlled charging schemes, distribution system operator (DSO) coordinates with the charging of EV fleets to ensure grid’s operating constraints are not violated. In fact, this refers to DSO setting upper bounds on power limits for EV charging. In this work, we demonstrate that if EVs inject reactive power into the grid while charging, DSO could issue higher upper bounds on the active power limits for the EVs for the same set of grid constraints. We demonstrate the concept in an 33-node test feeder with 1,500 EVs. Case studies show that in constrained distribution grids in coordinated charging, average costs of EV charging could be reduced if the charging takes place in the fourth P-Q quadrant compared to charging with unity power factor.

Assessment of post-Fukushima renewable energy policy in Japan's nation-wide power grid

International Nuclear Information System (INIS)

Komiyama, Ryoichi; Fujii, Yasumasa

2017-01-01

This manuscript analyzes an optimal power generation mix in Japan's nation-wide power grid by considering the post-Fukushima energy policy which puts a high priority on expanding renewable energy. The study is performed, employing an optimal power generation mix model which is characterized by detailed geographical resolution derived from 135 nodes and 166 high-voltage power transmission lines with 10-min temporal resolution. Simulated results reveal that renewable energy promotion policy underlies the necessity for capacity expansion of inter- or intra-regional power transmission lines in Japan in order to realize economical power system operation. In addition, the results show that the integration of massive variable renewable (VR) such as PV and wind decreases the capacity factor of power plant including ramp generator and possibly affects that profitability, which implies the challenge to ensure power system adequacy enough to control VR variability. - Highlights: • Authors analyze installable potential of renewable by Japan's power grid model. • Power grid of the model includes 135 nodes and 166 power transmission lines. • Renewable promotion underlies the necessity for capacity expansion of power lines. • Unremunerated power plants affect power grid adequacy under extensive renewable.

Solar Energy Grid Integration Systems (SEGIS): adding functionality while maintaining reliability and economics

Science.gov (United States)

Bower, Ward

2011-09-01

An overview of the activities and progress made during the US DOE Solar Energy Grid Integration Systems (SEGIS) solicitation, while maintaining reliability and economics is provided. The SEGIS R&D opened pathways for interconnecting PV systems to intelligent utility grids and micro-grids of the future. In addition to new capabilities are "value added" features. The new hardware designs resulted in smaller, less material-intensive products that are being viewed by utilities as enabling dispatchable generation and not just unpredictable negative loads. The technical solutions enable "advanced integrated system" concepts and "smart grid" processes to move forward in a faster and focused manner. The advanced integrated inverters/controllers can now incorporate energy management functionality, intelligent electrical grid support features and a multiplicity of communication technologies. Portals for energy flow and two-way communications have been implemented. SEGIS hardware was developed for the utility grid of today, which was designed for one-way power flow, for intermediate grid scenarios, AND for the grid of tomorrow, which will seamlessly accommodate managed two-way power flows as required by large-scale deployment of solar and other distributed generation. The SEGIS hardware and control developed for today meets existing standards and codes AND provides for future connections to a "smart grid" mode that enables utility control and optimized performance.

Opportunities and Benefits for Increasing Transmission Capacity between the US Eastern and Western Interconnections

Science.gov (United States)

Figueroa-Acevedo, Armando L.

Historically, the primary justification for building wide-area transmission lines in the US and around the world has been based on reliability and economic criteria. Today, the influence of renewable portfolio standards (RPS), Environmental Protection Agency (EPA) regulations, transmission needs, load diversity, and grid flexibility requirements drives interest in high capacity wide-area transmission. By making use of an optimization model to perform long-term (15 years) co-optimized generation and transmission expansion planning, this work explored the benefits of increasing transmission capacity between the US Eastern and Western Interconnections under different policy and futures assumptions. The model assessed tradeoffs between investments in cross-interconnection HVDC transmission, AC transmission needs within each interconnection, generation investment costs, and operational costs, while satisfying different policy compliance constraints. Operational costs were broken down into the following market products: energy, up-/down regulation reserve, and contingency reserve. In addition, the system operating flexibility requirements were modeled as a function of net-load variability so that the flexibility of the non-wind/non-solar resources increases with increased wind and solar investment. In addition, planning reserve constraints are imposed under the condition that they be deliverable to the load. Thus, the model allows existing and candidate generation resources for both operating reserves and deliverable planning reserves to be shared throughout the interconnections, a feature which significantly drives identification of least-cost investments. This model is used with a 169-bus representation of the North American power grid to design four different high-capacity wide-area transmission infrastructures. Results from this analysis suggest that, under policy that imposes a high-renewable future, the benefits of high capacity transmission between the Eastern and

Impact of external grid disturbances on nuclear power plants; Rueckwirkungen von Netzstoerungen auf Kernkraftwerke

Energy Technology Data Exchange (ETDEWEB)

Arains, Robert; Arnold, Simone; Brueck, Benjamin; Mueller, Christian; Quester, Claudia; Sommer, Dagmar

2017-06-15

The electrical design of nuclear power plants and the reliability of their electrical power supply including the offsite power supply are of high importance for the safe operation of the plants. The operating experience of recent years has shown that disturbances in the external grid can have impact on the electrical equipment of nuclear power plants. In the course of this project, possible causes and types of grid disturbances were identified. Based on these, scenarios of grid disturbances were developed. In order to investigate the impact of the developed scenarios of grid disturbances on the electrical equipment of nuclear power plants, the auxiliary power supply of a German pressurized water reactor of type Konvoi was simulated using the simulation tool NEPLAN. On the basis of the results of the analyses, it was identified whether there are possible measures to prevent the spread of grid disturbances in the plants which have not been implemented in the nuclear power plants today.

A Review on Direct Power Control for Applications to Grid Connected PWM Converters

Directory of Open Access Journals (Sweden)

T. A. Trivedi

2015-08-01

Full Text Available The Direct Power Control strategy has become popular as an alternative to the conventional vector oriented control strategy for grid connected PWM converters. In this paper, Direct Power Control as applied to various applications of grid connected converters is reviewed. The Direct Power Control for PWM rectifiers, Grid Connected DC/AC inverters applications such as renewable energy sources interface, Active Power Filters, Doubly Fed Induction Generators and AC-DC-AC converters are discussed. Control strategies such as Look-Up table based control, predictive control, Virtual Flux DPC, Model based DPC and DPC-Space Vector Modulation are critically reviewed. The effects of various key parameters such as selection of switching vector, sampling time, hysteresis band and grid interfacing on performance of direct power controlled converters are presented.

Differential evolution algorithm based automatic generation control for interconnected power systems with

Directory of Open Access Journals (Sweden)

Banaja Mohanty

2014-09-01

Full Text Available This paper presents the design and performance analysis of Differential Evolution (DE algorithm based Proportional–Integral (PI and Proportional–Integral–Derivative (PID controllers for Automatic Generation Control (AGC of an interconnected power system. Initially, a two area thermal system with governor dead-band nonlinearity is considered for the design and analysis purpose. In the proposed approach, the design problem is formulated as an optimization problem control and DE is employed to search for optimal controller parameters. Three different objective functions are used for the design purpose. The superiority of the proposed approach has been shown by comparing the results with a recently published Craziness based Particle Swarm Optimization (CPSO technique for the same interconnected power system. It is noticed that, the dynamic performance of DE optimized PI controller is better than CPSO optimized PI controllers. Additionally, controller parameters are tuned at different loading conditions so that an adaptive gain scheduling control strategy can be employed. The study is further extended to a more realistic network of two-area six unit system with different power generating units such as thermal, hydro, wind and diesel generating units considering boiler dynamics for thermal plants, Generation Rate Constraint (GRC and Governor Dead Band (GDB non-linearity.

Transient Control of Synchronous Machine Active and Reactive Power in Micro-grid Power Systems

Science.gov (United States)

Weber, Luke G.

There are two main topics associated with this dissertation. The first is to investigate phase-to-neutral fault current magnitude occurring in generators with multiple zero-sequence current sources. The second is to design, model, and tune a linear control system for operating a micro-grid in the event of a separation from the electric power system. In the former case, detailed generator, AC8B excitation system, and four-wire electric power system models are constructed. Where available, manufacturers data is used to validate the generator and exciter models. A gain-delay with frequency droop control is used to model an internal combustion engine and governor. The four wire system is connected through a transformer impedance to an infinite bus. Phase-to-neutral faults are imposed on the system, and fault magnitudes analyzed against three-phase faults to gauge their severity. In the latter case, a balanced three-phase system is assumed. The model structure from the former case - but using data for a different generator - is incorporated with a model for an energy storage device and a net load model to form a micro-grid. The primary control model for the energy storage device has a high level of detail, as does the energy storage device plant model in describing the LC filter and transformer. A gain-delay battery and inverter model is used at the front end. The net load model is intended to be the difference between renewable energy sources and load within a micro-grid system that has separated from the grid. Given the variability of both renewable generation and load, frequency and voltage stability are not guaranteed. This work is an attempt to model components of a proposed micro-grid system at the University of Wisconsin Milwaukee, and design, model, and tune a linear control system for operation in the event of a separation from the electric power system. The control module is responsible for management of frequency and active power, and voltage and reactive

An energy management system for off-grid power systems

Energy Technology Data Exchange (ETDEWEB)

Zelazo, Daniel [Universitaet Stuttgart, Institute for Systems Theory and Automatic Control, Stuttgart (Germany); Dai, Ran; Mesbahi, Mehran [University of Washington, Department of Aeronautics and Astronautics, Seattle, WA (United States)

2012-06-15

Next generation power management at all scales will rely on the efficient scheduling and operation of both generating units and loads to maximize efficiency and utility. The ability to schedule and modulate the demand levels of a subset of loads within a power system can lead to more efficient use of the generating units. These methods become increasingly important for systems that operate independently of the main utility, such as microgrid and off-grid systems. This work extends the principles of unit commitment and economic dispatch problems to off-grid power systems where the loads are also schedulable. We propose a general optimization framework for solving the energy management problem in these systems. An important contribution is the description of how a wide range of sources and loads, including those with discrete states, non-convex, and nonlinear cost or utility functions, can be reformulated as a convex optimization problem using, for example, a shortest path description. Once cast in this way, solution are obtainable using a sub-gradient algorithm that also lends itself to a distributed implementation. The methods are demonstrated by a simulation of an off-grid solar powered community. (orig.)

Design and analysis of active power control strategies for distributed generation inverters under unbalanced grid faults

NARCIS (Netherlands)

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

2010-01-01

Distributed power generation systems are expected to deliver active power into the grid and support it without interruption during unbalanced grid faults. Aiming to provide grid-interfacing inverters the flexibility to adapt to the coming change of grid requirements, an optimised active power

Vehicle-to-Grid Power in Danish Electric Power Systems

DEFF Research Database (Denmark)

Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

2009-01-01

The integration of renewable energy systems is often constrained by the variable nature of their output. This demands for the services of storing the electricity generated from most of the renewable energy sources. Vehicle-to-grid (V2G) power could use the inherent energy storage of electric...... vehicles and its quick response time to balance and stabilize a power system with fluctuating power. This paper outlines the use of battery electric vehicles in supporting large-scale integration of renewable energy in the Danish electric power systems. The reserve power requirements for a high renewable...... energy penetration could be met by an amount of V2G based electric vehicles less than 10% of the total vehicle need in Denmark. The participation of electric vehicle in ancillary services would earn significant revenues to the vehicle owner. The power balancing services of electric vehicles...

How to Integrate Variable Power Source into a Power Grid

Science.gov (United States)

Asano, Hiroshi

This paper discusses how to integrate variable power source such as wind power and photovoltaic generation into a power grid. The intermittent renewable generation is expected to penetrate for less carbon intensive power supply system, but it causes voltage control problem in the distribution system, and supply-demand imbalance problem in a whole power system. Cooperative control of customers' energy storage equipment such as water heater with storage tank for reducing inverse power flow from the roof-top PV system, the operation technique using a battery system and the solar radiation forecast for stabilizing output of variable generation, smart charging of plug-in hybrid electric vehicles for load frequency control (LFC), and other methods to integrate variable power source with improving social benefits are surveyed.

Reliability analysis of grid connected small wind turbine power electronics

International Nuclear Information System (INIS)

Arifujjaman, Md.; Iqbal, M.T.; Quaicoe, J.E.

2009-01-01

Grid connection of small permanent magnet generator (PMG) based wind turbines requires a power conditioning system comprising a bridge rectifier, a dc-dc converter and a grid-tie inverter. This work presents a reliability analysis and an identification of the least reliable component of the power conditioning system of such grid connection arrangements. Reliability of the configuration is analyzed for the worst case scenario of maximum conversion losses at a particular wind speed. The analysis reveals that the reliability of the power conditioning system of such PMG based wind turbines is fairly low and it reduces to 84% of initial value within one year. The investigation is further enhanced by identifying the least reliable component within the power conditioning system and found that the inverter has the dominant effect on the system reliability, while the dc-dc converter has the least significant effect. The reliability analysis demonstrates that a permanent magnet generator based wind energy conversion system is not the best option from the point of view of power conditioning system reliability. The analysis also reveals that new research is required to determine a robust power electronics configuration for small wind turbine conversion systems.

Wireless Infrastructure M2M Network For Distributed Power Grid Monitoring.

Science.gov (United States)

Gharavi, Hamid; Hu, Bin

2017-01-01

With the massive integration of distributed renewable energy sources (RESs) into the power system, the demand for timely and reliable network quality monitoring, control, and fault analysis is rapidly growing. Following the successful deployment of Phasor Measurement Units (PMUs) in transmission systems for power monitoring, a new opportunity to utilize PMU measurement data for power quality assessment in distribution grid systems is emerging. The main problem however, is that a distribution grid system does not normally have the support of an infrastructure network. Therefore, the main objective in this paper is to develop a Machine-to-Machine (M2M) communication network that can support wide ranging sensory data, including high rate synchrophasor data for real-time communication. In particular, we evaluate the suitability of the emerging IEEE 802.11ah standard by exploiting its important features, such as classifying the power grid sensory data into different categories according to their traffic characteristics. For performance evaluation we use our hardware in the loop grid communication network testbed to access the performance of the network.

8-dimensional lattice optimized formats in 25-GBaud/s VCSEL based IM/DD optical interconnections

DEFF Research Database (Denmark)

Lu, Xiaofeng; Tafur Monroy, Idelfonso

2015-01-01

Temporally combined 4- and 8-dimensional lattice grids optimized modulation formats for VCSEL based IM/DD short-reach optical inter-connections has been proposed and investigated numerically together with its conventional counterpart PAM-4. © 2015 OSA.......Temporally combined 4- and 8-dimensional lattice grids optimized modulation formats for VCSEL based IM/DD short-reach optical inter-connections has been proposed and investigated numerically together with its conventional counterpart PAM-4. © 2015 OSA....

Power systems signal processing for smart grids

CERN Document Server

Ribeiro, Paulo Fernando; Ribeiro, Paulo Márcio; Cerqueira, Augusto Santiago

2013-01-01

With special relation to smart grids, this book provides clear and comprehensive explanation of how Digital Signal Processing (DSP) and Computational Intelligence (CI) techniques can be applied to solve problems in the power system. Its unique coverage bridges the gap between DSP, electrical power and energy engineering systems, showing many different techniques applied to typical and expected system conditions with practical power system examples. Surveying all recent advances on DSP for power systems, this book enables engineers and researchers to understand the current state of the art a

Smart power grids 2011

CERN Document Server

Keyhani, Ali

2012-01-01

Electric power systems are experiencing significant changes at the worldwide scale in order to become cleaner, smarter, and more reliable. This edited book examines a wide range of topics related to these changes, which are primarily caused by the introduction of information technologies, renewable energy penetration, digitalized equipment, new operational strategies, and so forth. The emphasis will be put on the modeling and control of smart grid systems. This book addresses research topics such as high efficiency transforrmers, wind turbines and generators, fuel cells, or high speed turbines

The construction of power grid operation index system considering the risk of maintenance

Science.gov (United States)

Tang, Jihong; Wang, Canlin; Jiang, Xinfan; Ye, Jianhui; Pan, Feilai

2018-02-01

In recent years, large-scale blackout occurred at home and abroad caused widespread concern about the operation of the grid in the world, and the maintenance risk is an important indicator of grid safety. The barrier operation of the circuit breaker exists in the process of overhaul of the power grid. The operation of the different barrier is of great significance to the change of the power flow, thus affecting the safe operation of the system. Most of the grid operating status evaluation index system did not consider the risk of maintenance, to this end, this paper from the security, economy, quality and cleanliness of the four angles, build the power grid operation index system considering the risk of maintenance.

18 CFR 292.306 - Interconnection costs.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Interconnection costs... § 292.306 Interconnection costs. (a) Obligation to pay. Each qualifying facility shall be obligated to pay any interconnection costs which the State regulatory authority (with respect to any electric...

Flexible Power Regulation and Current-limited Control of Grid-connected Inverter under Unbalanced Grid Voltage Faults

DEFF Research Database (Denmark)

Guo, Xiaoqiang; Liu, Wenzhao; Lu, Zhigang

2017-01-01

The grid-connected inverters may experience excessive current stress in case of unbalanced grid voltage Fault Ride Through (FRT), which significantly affects the reliability of the power supply system. In order to solve the problem, the inherent mechanisms of the excessive current phenomenon...... with the conventional FRT solutions are discussed. The quantitative analysis of three phase current peak values are conducted and a novel current-limited control strategy is proposed to achieve the flexible active and reactive power regulation and successful FRT in a safe current operation area with the aim...

Power Quality of Grid-Connected Wind Turbines with DFIG and Their Interaction with the Grid

DEFF Research Database (Denmark)

Sun, Tao

quality issues of grid-connected wind turbines and the interaction between wind turbines and the grid. The specific goal of the research has been to investigate flicker emission and mitigation of grid-connected wind turbines with doubly fed induction generators (DFIG) during continuous operation...... measures are proposed to mitigate the flicker levels produced by grid-connected wind turbines with DFIG, respectively by wind turbine output reactive power control and using STATCOM. Simulation results demonstrate that these two measures are effective for flicker mitigation regardless of mean wind speed....... To evaluate the flicker levels produced by grid-connected wind turbines with DFIG, a flickermeter model is developed according to the IEC standard IEC 61000-4-15, which simulates the response of the lamp-eye-brain chain and provides on-line statistical analysis ofthe flicker signal and the final results...

Grid Integration of PV Power based on PHIL testing using different Interface Algorithms

DEFF Research Database (Denmark)

Craciun, Bogdan-Ionut; Kerekes, Tamas; Sera, Dezso

2013-01-01

to be more active in grid support. Therefore, a better understanding and detailed analysis of the PV systems interaction with the grid is needed; hence power hardware in the loop (PHIL) testing involving PV power became an interesting subject to look into. To test PV systems for grid code (GC) compliance......Photovoltaic (PV) power among all renewable energies had the most accelerated growth rate in terms of installed capacity in recent years. Transmission System Operators (TSOs) changed their perspective about PV power and started to include it into their planning and operation, imposing PV systems...

IKT-Gateway as a bridge between dual-purpose power plant and smart grid; IKT-Gateway als Bruecke zwischen BHKW und Smart Grid

Energy Technology Data Exchange (ETDEWEB)

Neumann, Joerg [SSV Software Systems GmbH, Hannover (Germany). Bereich Vertrieb und Marketing

2012-07-15

The way to a smart grid leads via the interconnection of distributed energy producers and consumers. Within the total network, energy producers and consumers have to communicate meaningfully with each other. This is a great performance for a reliable and performant long-distance service. In the case of 2G Energietechnik AG (Heek, Federal Republic of Germany), SSV Software Systems GmbH (Hannover, Federal Republic of Germany) has met this challenge with an ICT-based gateway solution mastered.

Local Reactive Power Control Methods for Overvoltage Prevention of Distributed Solar Inverters in Low-Voltage Grids

DEFF Research Database (Denmark)

Demirok, Erhan; Gonzalez, Pablo Casado; Frederiksen, Kenn H. B.

2011-01-01

on sensitivity analysis. The sensitivity analysis shows that the same amount of reactive power becomes more effective for grid voltage support if the solar inverter is located at the end of a feeder. Based on this fundamental knowledge, a location-dependent power factor set value can be assigned to each inverter......voltage (LV) grids by means of solar inverters with reactive power control capability. This paper underlines weak points of standard reactive power strategies which are already imposed by certain grid codes, and then, the study introduces a new reactive power control method that is based......, and the grid voltage support can be achieved with less total reactive power consumption. In order to prevent unnecessary reactive power absorption from the grid during admissible voltage range or to increase reactive power contribution from the inverters that are closest to the transformer during grid...

Prospects of Foreign Capital Raising for Russian Power Grid Companies

Directory of Open Access Journals (Sweden)

N. N. Shvets

2015-01-01

Full Text Available The power sector reform in Russia saw capital raising as one of the key objectives. Additional investments are necessary, in particular, for renovation of fixed assets which are ca. 70% worn out. The official Strategy for the development of the Russian power grid also provides for privatization of certain companies and foreign investors are considered among others as the target audience. Upon prospective privatization the sector is expected not only to experience a certain increase in capital expenditures, but also to benefit from foreign expertise and efficiency enhancement. At the moment, however, the privatization plans are hard to implement due to a number of obstacles. Prospective investors are mostly concerned about the lack of transparent regulation and clear development strategy of the industry. This is particularly relevant to the tariff system, which has been continuously altered in recent years. This might be explained by the need of the state support by other sectors, which is often provided at the expense of the power industry. Furthermore, the prospects of foreign capital raising are negatively influenced by the conflict in Ukraine and the corresponding negative perception of potential investors. The above factors result in the decrease in value of power grid companies as well as in the lack of visibility regarding the prospects of the sector development. Privatization thus becomes unreasonable both for the state and prospective investors. At the same time, despite the sector specifics, there are precedents of successful sale of power grid assets to private investors by international peers. Particularly, Vatenfall and Forum have recently closed relevant transactions, nothing to say about the power grid sector of Brazil, majorly controlled by private owners. Transparent regulation, clear pricing rules and well-balanced economic policy are, indeed, indispensable prerequisites for successful privatization. Those might back up a

The impact of model detail on power grid resilience measures

Science.gov (United States)

Auer, S.; Kleis, K.; Schultz, P.; Kurths, J.; Hellmann, F.

2016-05-01

Extreme events are a challenge to natural as well as man-made systems. For critical infrastructure like power grids, we need to understand their resilience against large disturbances. Recently, new measures of the resilience of dynamical systems have been developed in the complex system literature. Basin stability and survivability respectively assess the asymptotic and transient behavior of a system when subjected to arbitrary, localized but large perturbations in frequency and phase. To employ these methods that assess power grid resilience, we need to choose a certain model detail of the power grid. For the grid topology we considered the Scandinavian grid and an ensemble of power grids generated with a random growth model. So far the most popular model that has been studied is the classical swing equation model for the frequency response of generators and motors. In this paper we study a more sophisticated model of synchronous machines that also takes voltage dynamics into account, and compare it to the previously studied model. This model has been found to give an accurate picture of the long term evolution of synchronous machines in the engineering literature for post fault studies. We find evidence that some stable fix points of the swing equation become unstable when we add voltage dynamics. If this occurs the asymptotic behavior of the system can be dramatically altered, and basin stability estimates obtained with the swing equation can be dramatically wrong. We also find that the survivability does not change significantly when taking the voltage dynamics into account. Further, the limit cycle type asymptotic behaviour is strongly correlated with transient voltages that violate typical operational voltage bounds. Thus, transient voltage bounds are dominated by transient frequency bounds and play no large role for realistic parameters.