Showing papers on "Smart grid published in 2005"

Toward a smart grid: power delivery for the 21st century

Abstract: In this article, we present the security, agility, and robustness/survivability of a large-scale power delivery infrastructure that faces new threats and unanticipated conditions. By way of background, we present a brief overview of the past work on the challenges faced in online parameter estimation and real-time adaptive control of a damaged F-15 aircraft. This work, in part, provided the inspiration and laid the foundation in the 1990s for the flight testing of a fast parameter estimation/modeling and reconfigurable aircraft control system that allowed the F-15 to become self-healing in the face of damaged equipment.

A failure to communicate: next generation communication requirements, technologies, and architecture for the electric power grid

Abstract: The power grid engineering community is beginning to recognize a need to fundamentally transform the capabilities of the communication infrastructure that supports power grid operations Better communications are key to providing improvements in security, efficiency, and reliability This paper reviews current data communication practices for the grid and describes a new approach to data communications that will help realize the vision of a more resilient and efficient "smart" grid

Power quality : interactions between distributed energy resources,the grid, and other customers

Abstract: This paper presents the three aspects of power quality concerning distributed energy resources (DER). The voltage quality experienced by a DER unit impacts the performance of the unit: bad voltage ...

Method and system for ac power grid monitoring

Abstract: A method and system allows for substantially real-time monitoring of the operational dynamics of power plants (16, 18, 20) and other components comprising an AC power grid, by using information collected from a network of power grid frequency detection and reporting devices (22, 24, 26). The invention allows for the substantially real-time detection and reporting of certain power grid events such as power plant trips.

Electric grid stability and the design of sustainable energy systems

Abstract: Today, in most countries, electricity is produced either on hydropower or on large steam turbines on the basis of fossil fuels or nuclear power. Electricity from distributed generation constitutes only small amounts. Until now, the task of balancing supply and demand and the task of securing frequency and voltage on the grid has been left solely to large production units. Meanwhile, the implementation of cleaner technologies, such as renewable energy, combined heat and power production and energy conservation, is necessary for future sustainable energy systems. Consequently, such distributed production units sooner or later need to contribute to the task of securing a balance between electricity production and consumer demands. This paper presents technical designs of potential future flexible energy systems, which will be able both to balance production and demand and to secure voltage and frequency requirements on the grid.

Power quality aspects of a future micro grid

Abstract: Due to the increase of distributed generators (DG) in the public grid some parts, with high penetration of DGs, could be transformed into an autonomously operating micro grid. This paper will show how the grid of an existing Holyday park can be changed into an autonomous micro grid. An additional control system as well as additional storage systems and power electronics have to be implemented in order to maintain the balance between load and generated power, and to guarantee the quality of supply on an acceptable level. Therefore a measurement program is running concerning the generated power and the load behavior and some aspects of the quality of supply. This paper is especially focused on the existing harmonic problem coming from the interaction between grid components and installed solar inverters. At the end a new power quality test laboratory is presented

Grid code provisions for wind generators in Ireland

Abstract: This paper outlines how ESB National Grid (ESBNG), the transmission system operator (TSO) for the Republic of Ireland, developed the grid code for wind farm power stations (WFPS). It discusses the topics considered, how the code requirements apply to the distribution network and finally outlines some future work.

Impact of wind energy in a future power grid

Abstract: This thesis investigates on various levels the technical impact of wind power on a power system. The first part develops detailed dynamic models of wind turbines or farms in software dedicated to power system simulation. These models are used to assess the impact of wind speed or power grid disturbances. The models are a suitable tool to investigate the turbine's ability to provide 'ancillary services', i.e. voltage control or other types of grid support, and to assess the impact of adapting grid connection requirements specifically for wind turbines. The second part quantifies the hourly and daily power output fluctuations of an aggregated wind park for the specific case study of the Belgian control zone, for various scenarios. Furthermore, the potential contribution to the abatement of carbon dioxide emissions by the total power generation park is assessed. The final part presents the results of a multidisciplinary study with regard to optimal offshore wind developments in the Belgian Continental Shelf, including aspects with regard to seabed properties, wind resources, turbine types and power system availability.

Getting a grip on the grid

Abstract: When accidents occur in the systems that comprise an interconnected electric power grid, these accidents must be regarded as the symptom of inadequate grid design and management. As such, there is an urgent need for cross-regional reforms so that the best available technology is promptly put to use, without lengthy delays arising from the legislative or regulatory process. The reform process needs to recognize that all interconnected systems will experience major blackouts if operated outside intended design limits. Ultimately, end users must accept the price for reliability or the consequence of unavailability.

Automatic power saving in a grid environment

Abstract: A global power management for a grid is provided. A grid administrator is connected to the group nodes of the grid. During operation, the grid administrator calculates the cost of operations, such as electricity and cooling costs, and migrates the workload of the grid to minimize the cost of operations. In particular, the grid administrator may deactivate or power down one or more of the nodes in order to minimize the cost of operations.

Power system restoration collaborative grid based on grid computing environment

Abstract: Based on grid-computing environment, a power system restoration collaborative grid (PSRC grid) is proposed, which aims to make it possible for power system operators from different systems to collaborate and exchange information when large-scale blackouts occur. The architecture of the PSRC grid system is designed according to the open grid services architecture. A prototype of the PSRC grid is developed with Globus Toolkit 3.0. It shows considerable potential of dealing the data share and wide-area distributed computing for power system collaborative restoration.

Optimal operation of photovoltaic/utility grid interconnected electrical power system using neural network

Abstract: The performance of photovoltaic power system interconnected with utility grid can be improved through an application of advanced control method. This paper introduces an application of an artificial neural network on the operation control of the photovoltaic/utility grid to improve system efficiency and reliability. The generated power from photovoltaic solar cells array have been calculated by a computer program under known insolation and temperature. The computer program which proposed here and applied to carry out these calculations is based on the minimization of the power purchase from grid. This paper focus on a hybrid system consists of photovoltaic system accompanied with battery storage interconnected with utility grid taking into account the variation of solar radiation and load demand during the day. Different feed forward neural network architectures are trained and tested with data containing a variety of operation patterns. A simulation is carried out over one year using the hourly data of the load demand, insolation and temperature at El'Zafranna site, Egypt as a case study. The results show that the selected neural network architecture (5+9+4) gives reasonably accurate operation of photovoltaic/utility grid accompanied with battery storage.

Coordinate control of distributed generations with power converters in a micro grid

Abstract: For extensive utilization of distributed generation with the objectives of more efficient use of energy and introduction of renewable energy sources, the construction of a micro grid at demand end is inevitable. The micro grid should operate independently and have a good neighbor relation with the power grid, which supplies base power to it. A coordinate control scheme of distributed generations is studied. It has three layers of structure. The integrated control system is quite similar to that of power system other than its scale. Because of the limited number of generations and customers, the variation of power unbalance between supply and demand is fast and large. To stabilize the system and maintain power supply quality, the micro grid is subdivided into local distribution network groups. The local group control system regulates generations inside it in coordination with other groups and transmits operational information in it to the integrated control system. Each controllable generation has its own control system and regulates its output with the command from the local group control system. The distributed generation on the market, including the battery energy storage, is generally connected to the network through the power converter system. Because it can not autonomously follow the power variation, a novel control scheme should be incorporated into the control system of power converter system and the local level control. Their performances in operation of a micro grid are verified with simulations using EMTDC/PSCAD. The coordination between local group control systems for the load following control is under test in a model grid for experiment. A demonstration system is planned to construct on this control scheme

China power grid and its future development

Abstract: The uneven distribution of energy resources and power load center, as an impetus, is driving China power grid to strengthen its national-wide interconnection to achieve high utilization efficiency. The current situation and planning of China power grid is introduced in this paper. Specific problems considered in planning of national-wide interconnection and their countermeasures are analyzed, such as low frequency oscillation, stability of receiving-end system, and security of multi-infeed HVDC systems etc.

Case Study: Fuel Cell Micro Grid Operation at the 2004 Democratic National Convention

Abstract: The 2004 Democratic National Convention (DNC) in downtown Boston presented an energy challenge. The large, attendant media presence required a great deal of additional power for temporary studios, satellite up-links, etc., that could not be supplied by the constrained electric utility infrastructure. To meet this need, an independent micro grid was constructed consisting of two rail-mounted diesel-generators and a trailer-mounted fuel cell power plant. The fuel cell was a DFC300 produced by FuelCell Energy, Inc. The DFC300 is a 250 kW rated power plant, capable of both grid connected and grid independent operation. The DNC micro grid represented the first application in which the DFC300 operated in parallel with diesel generators independent of the electric utility grid. In addition to explaining the fuel cell power plant operating modes, this article describes the specific planning, challenges and operating results of the unit in the DNC micro grid. It will also examine the potential benefits of fuel cells in future micro grid applications.

Characteristics and development tendency of main framework in the future for regional power grid in China

Abstract: The background of regional power grid planning and its important basic condition for the Northeast, North China, East China, and Northwest regional power grid in China were introduced. This power grid planning must face to the external environment including how to insist the unified and scientific planning, and coordinative development for power grid and power source, must set up the idea of regional power grid planning guided by nation-wide power grid interconnection planning, and the provincial-level power grid planning guided by regional power grid planning. The development of power grid is how to satisfy the needs of establishing competitive power market, and how to make good power grid planning under the condition of the serious disequilibrium of power supply and demand. The way of development, characteristics of structure and its development tendency of main framework for each regional power grid were analyzed. The development of regional power grid should firstly meet the guidance of nation-wide power grid interconnection strategy, inter-regional power flow and inter-regional interconnection mode. Secondly, the verification of the schemes for the development of regional main framework was carried out, and the development tendency of main framework, the key ring power grid of receiving end and transmission channel were described according to the recommended scheme. Some problems needed to solve for power grid development were presented from technical points of view.

Electric dreams [global electrification]

Abstract: This article examines the scale of the problem of global electrification and some solutions to this problem. In particular, it details the Intelligrid project. Intelligrid aims to develop the overall technical framework, or architecture, for the intelligent electricity grid of the future, and is driven by the Electric Power Research Institute's affiliate, the Electricity Innovation Institute (E2I), and the Consortium for an Electric Infrastructure to Support a Digital Society (CEIDS). Described as an open, systems-based architecture, Intelligrid is seen as crucial to supporting the data communications networks and equipment needed for a future power delivery infrastructure.

Problems to be emphatically researched in power planning of China southern power grid

Abstract: Following the deepening of electric power structural reform and the capacity raising of China's west-to-east power transmission project, this paper takes into account the development characteristics and power planning function of southern power grid in China, and analyzes some problems to be emphatically researched in the power planning of the grid from the following sides: power source and grid plan, reactive power plan, power grid short-circuit current level, power grid reliability, research of new techniques to power grid, relevant policy and rules of law.

Measures to control and reduce short-circuit current for East China Power Grid

Abstract: The short-circuit current level of the main 500 kV loop network of East China Power Grid is analyzed.Experience of managing the over-standard short-circuit current,as well as the countermeasures adopted by the Grid are summarized,and the scheme of controlling and reducing the short-circuit current for load-central substations in East China Power Grid during 2006 to 2007 are illuminated.

Study of several problems of power grid planning in power market environment

Abstract: The power grid planning system, the power grid investment system and the transmission pricing system in the power market environment both abroad and at home were summarized. The new problems and challenges encountered in power grid planning in power market environment were analyzed, especially the uncertainties in market condition. The new models and methods for solving the power grid planning problems in market condition were summed up and problems needing further efforts to settle for power grid planning in power market environment were put forward.

Idea on grid plannig for short-circuit current limitation

Abstract: The short-circuit current in the power system is increasing year by year together with the enhancement of the power grid and short-circuit current limitation in the power system has become one of the important problems in power grid planning. The reason of short-circuit current increase was analyzed and the limitation measures from the view of grid planning were introduced.