Biomass energy inventory and mapping system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasile, J.D.

1993-12-31

A four-stage biomass energy inventory and mapping system was conducted for the entire State of Ohio. The product is a set of maps and an inventory of the State of Ohio. The set of amps and an inventory of the State`s energy biomass resource are to a one kilometer grid square basis on the Universal Transverse Mercator (UTM) system. Each square kilometer is identified and mapped showing total British Thermal Unit (BTU) energy availability. Land cover percentages and BTU values are provided for each of nine biomass strata types for each one kilometer grid square. LANDSAT satellite data was usedmore » as the primary stratifier. The second stage sampling was the photointerpretation of randomly selected one kilometer grid squares that exactly corresponded to the LANDSAT one kilometer grid square classification orientation. Field sampling comprised the third stage of the energy biomass inventory system and was combined with the fourth stage sample of laboratory biomass energy analysis using a Bomb calorimeter and was then used to assign BTU values to the photointerpretation and to adjust the LANDSAT classification. The sampling error for the whole system was 3.91%.« less

Near real-time traffic routing

NASA Technical Reports Server (NTRS)

Yang, Chaowei (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor); Cao, Ying (Inventor)

2012-01-01

A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

Understanding Cognitive and Collaborative Work: Observations in an Electric Transmission Operations Control Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obradovich, Jodi H.

2011-09-30

This paper describes research that is part of an ongoing project to design tools to assist in the integration of renewable energy into the electric grid. These tools will support control room dispatchers in real-time system operations of the electric power transmission system which serves much of the Western United States. Field observations comprise the first phase of this research in which 15 operators have been observed over various shifts and times of day for approximately 90 hours. Findings describing some of the cognitive and environmental challenges of managing the dynamically changing electric grid are presented.

A package for 3-D unstructured grid generation, finite-element flow solution and flow field visualization

NASA Technical Reports Server (NTRS)

Parikh, Paresh; Pirzadeh, Shahyar; Loehner, Rainald

1990-01-01

A set of computer programs for 3-D unstructured grid generation, fluid flow calculations, and flow field visualization was developed. The grid generation program, called VGRID3D, generates grids over complex configurations using the advancing front method. In this method, the point and element generation is accomplished simultaneously, VPLOT3D is an interactive, menudriven pre- and post-processor graphics program for interpolation and display of unstructured grid data. The flow solver, VFLOW3D, is an Euler equation solver based on an explicit, two-step, Taylor-Galerkin algorithm which uses the Flux Corrected Transport (FCT) concept for a wriggle-free solution. Using these programs, increasingly complex 3-D configurations of interest to aerospace community were gridded including a complete Space Transportation System comprised of the space-shuttle orbitor, the solid-rocket boosters, and the external tank. Flow solutions were obtained on various configurations in subsonic, transonic, and supersonic flow regimes.

Performance evaluation of cognitive radio in advanced metering infrastructure communication

NASA Astrophysics Data System (ADS)

Hiew, Yik-Kuan; Mohd Aripin, Norazizah; Din, Norashidah Md

2016-03-01

Smart grid is an intelligent electricity grid system. A reliable two-way communication system is required to transmit both critical and non-critical smart grid data. However, it is difficult to locate a huge chunk of dedicated spectrum for smart grid communications. Hence, cognitive radio based communication is applied. Cognitive radio allows smart grid users to access licensed spectrums opportunistically with the constraint of not causing harmful interference to licensed users. In this paper, a cognitive radio based smart grid communication framework is proposed. Smart grid framework consists of Home Area Network (HAN) and Advanced Metering Infrastructure (AMI), while AMI is made up of Neighborhood Area Network (NAN) and Wide Area Network (WAN). In this paper, the authors only report the findings for AMI communication. AMI is smart grid domain that comprises smart meters, data aggregator unit, and billing center. Meter data are collected by smart meters and transmitted to data aggregator unit by using cognitive 802.11 technique; data aggregator unit then relays the data to billing center using cognitive WiMAX and TV white space. The performance of cognitive radio in AMI communication is investigated using Network Simulator 2. Simulation results show that cognitive radio improves the latency and throughput performances of AMI. Besides, cognitive radio also improves spectrum utilization efficiency of WiMAX band from 5.92% to 9.24% and duty cycle of TV band from 6.6% to 10.77%.

Uniformity on the grid via a configuration framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Igor V Terekhov et al.

2003-03-11

As Grid permeates modern computing, Grid solutions continue to emerge and take shape. The actual Grid development projects continue to provide higher-level services that evolve in functionality and operate with application-level concepts which are often specific to the virtual organizations that use them. Physically, however, grids are comprised of sites whose resources are diverse and seldom project readily onto a grid's set of concepts. In practice, this also creates problems for site administrators who actually instantiate grid services. In this paper, we present a flexible, uniform framework to configure a grid site and its facilities, and otherwise describe the resourcesmore » and services it offers. We start from a site configuration and instantiate services for resource advertisement, monitoring and data handling; we also apply our framework to hosting environment creation. We use our ideas in the Information Management part of the SAM-Grid project, a grid system which will deliver petabyte-scale data to the hundreds of users. Our users are High Energy Physics experimenters who are scattered worldwide across dozens of institutions and always use facilities that are shared with other experiments as well as other grids. Our implementation represents information in the XML format and includes tools written in XQuery and XSLT.« less

Multiprocessor computer overset grid method and apparatus

DOEpatents

Barnette, Daniel W.; Ober, Curtis C.

2003-01-01

A multiprocessor computer overset grid method and apparatus comprises associating points in each overset grid with processors and using mapped interpolation transformations to communicate intermediate values between processors assigned base and target points of the interpolation transformations. The method allows a multiprocessor computer to operate with effective load balance on overset grid applications.

The Amsterdam quintuplet nuclear microprobe

NASA Astrophysics Data System (ADS)

van den Putte, M. J. J.; van den Brand, J. F. J.; Jamieson, D. N.; Rout, B.; Szymanski, R.

2003-09-01

A new nuclear microprobe comprising of a quintuplet lens system is being constructed at the Ion Beam Facility of the "Vrije Universiteit" Amsterdam in collaboration with the Microanalytical Research Centre of the University of Melbourne. An overview of the Amsterdam set-up will be presented. Detailed characterisation of the individual lenses was performed with the grid shadow method using a 2000 mesh Cu grid mounted at a relative angle of 0.5° to the vertical lens line focus. The lenses were found to have very low parasitic aberrations equal or below the minimum detectable limit for the method, which was approximately 0.1% for the sextupole component and 0.2% for the octupole component. We present experimental and theoretical grid shadow patterns, showing results for all five lenses.

The State of NASA's Information Power Grid

NASA Technical Reports Server (NTRS)

Johnston, William E.; Vaziri, Arsi; Tanner, Leigh Ann; Feiereisen, William J.; Thigpen, William; Biegel, Bryan (Technical Monitor)

2001-01-01

This viewgraph presentation transfers the concept of the power grid to information sharing in the NASA community. An information grid of this sort would be characterized as comprising tools, middleware, and services for the facilitation of interoperability, distribution of new technologies, human collaboration, and data management. While a grid would increase the ability of information sharing, it would not necessitate it. The onus of utilizing the grid would rest with the users.

MAGNETIC GRID

DOEpatents

Post, R.F.

1960-08-01

An electronic grid is designed employing magnetic forces for controlling the passage of charged particles. The grid is particularly applicable to use in gas-filled tubes such as ignitrons. thyratrons, etc., since the magnetic grid action is impartial to the polarity of the charged particles and, accordingly. the sheath effects encountered with electrostatic grids are not present. The grid comprises a conductor having sections spaced apart and extending in substantially opposite directions in the same plane, the ends of the conductor being adapted for connection to a current source.

Grid Integration and the Carrying Capacity of the U.S. Grid to Incorporate Variable Renewable Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Jaquelin; Denholm, Paul; Speer, Bethany

2015-04-23

In the United States and elsewhere, renewable energy (RE) generation supplies an increasingly large percentage of annual demand, including nine U.S. states where wind comprised over 10% of in-state generation in 2013. This white paper summarizes the challenges to integrating increasing amounts of variable RE, identifies emerging practices in power system planning and operation that can facilitate grid integration, and proposes a unifying concept—economic carrying capacity—that can provide a framework for evaluating actions to accommodate higher penetrations of RE. There is growing recognition that while technical challenges to variable RE integration are real, they can generally be addressed via amore » variety of solutions that vary in implementation cost. As a result, limits to RE penetration are primarily economic, driven by factors that include transmission and the flexibility of the power grid to balance supply and demand. This limit can be expressed as economic carrying capacity, or the point at which variable RE is no longer economically competitive or desirable to the system or society.« less

High pressure xenon ionization detector

DOEpatents

Markey, J.K.

1989-11-14

A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

High pressure xenon ionization detector

DOEpatents

Markey, John K.

1989-01-01

A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

Petroleum system modeling of the western Canada sedimentary basin - isopach grid files

USGS Publications Warehouse

Higley, Debra K.; Henry, Mitchell E.; Roberts, Laura N.R.

2005-01-01

This publication contains zmap-format grid files of isopach intervals that represent strata associated with Devonian to Holocene petroleum systems of the Western Canada Sedimentary Basin (WCSB) of Alberta, British Columbia, and Saskatchewan, Canada. Also included is one grid file that represents elevations relative to sea level of the top of the Lower Cretaceous Mannville Group. Vertical and lateral scales are in meters. The age range represented by the stratigraphic intervals comprising the grid files is 373 million years ago (Ma) to present day. File names, age ranges, formation intervals, and primary petroleum system elements are listed in table 1. Metadata associated with this publication includes information on the study area and the zmap-format files. The digital files listed in table 1 were compiled as part of the Petroleum Processes Research Project being conducted by the Central Energy Resources Team of the U.S. Geological Survey, which focuses on modeling petroleum generation, 3 migration, and accumulation through time for petroleum systems of the WCSB. Primary purposes of the WCSB study are to Construct the 1-D/2-D/3-D petroleum system models of the WCSB. Actual boundaries of the study area are documented within the metadata; excluded are northern Alberta and eastern Saskatchewan, but fringing areas of the United States are included.Publish results of the research and the grid files generated for use in the 3-D model of the WCSB.Evaluate the use of petroleum system modeling in assessing undiscovered oil and gas resources for geologic provinces across the World.

Linking the open source, spatial electrification tool (ONSSET) and the open source energy modelling system (OSeMOSYS), with a focus on Sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Mentis, Dimitrios; Howells, Mark; Rogner, Holger; Korkovelos, Alexandros; Arderne, Christopher; Siyal, Shahid; Zepeda, Eduardo; Taliotis, Constantinos; Bazilian, Morgan; de Roo, Ad; Tanvez, Yann; Oudalov, Alexandre; Scholtz, Ernst

2017-04-01

In September 2015, the United Nations General Assembly adopted Agenda 2030, which comprises a set of 17 Sustainable Development Goals (SDGs) defined by 169 targets. "Ensuring access to affordable, reliable, sustainable and modern energy for all by 2030" is the seventh goal (SDG7). While access to energy refers to more than electricity, the latter is the central focus of this work. According to the World Bank's 2015 Global Tracking Framework, roughly 15% of world population (or 1.1 billion people) lack access to electricity, and many more rely on poor quality electricity services. The majority of those without access (87%) reside in rural areas. This paper presents results of a Geographic Information Systems (GIS) approach coupled with open access data and linked to the Electricity Model Base for Africa (TEMBA), a model that represents each continental African country's electricity supply system. We present least-cost electrification strategies on a country-by-country basis for Sub-Saharan Africa. The electrification options include grid extension, mini-grid and stand-alone systems for rural, peri-urban, and urban contexts across the economy. At low levels of electricity demand there is a strong penetration of standalone technologies. However, higher electricity demand levels move the favourable electrification option from stand-alone systems to mini grid and to grid extensions.

A three-dimensional application with the numerical grid generation code: EAGLE (utilizing an externally generated surface)

NASA Technical Reports Server (NTRS)

Houston, Johnny L.

1990-01-01

Program EAGLE (Eglin Arbitrary Geometry Implicit Euler) is a multiblock grid generation and steady-state flow solver system. This system combines a boundary conforming surface generation, a composite block structure grid generation scheme, and a multiblock implicit Euler flow solver algorithm. The three codes are intended to be used sequentially from the definition of the configuration under study to the flow solution about the configuration. EAGLE was specifically designed to aid in the analysis of both freestream and interference flow field configurations. These configurations can be comprised of single or multiple bodies ranging from simple axisymmetric airframes to complex aircraft shapes with external weapons. Each body can be arbitrarily shaped with or without multiple lifting surfaces. Program EAGLE is written to compile and execute efficiently on any CRAY machine with or without Solid State Disk (SSD) devices. Also, the code uses namelist inputs which are supported by all CRAY machines using the FORTRAN Compiler CF177. The use of namelist inputs makes it easier for the user to understand the inputs and to operate Program EAGLE. Recently, the Code was modified to operate on other computers, especially the Sun Spare4 Workstation. Several two-dimensional grid configurations were completely and successfully developed using EAGLE. Currently, EAGLE is being used for three-dimension grid applications.

Towards Stochastic Optimization-Based Electric Vehicle Penetration in a Novel Archipelago Microgrid.

PubMed

Yang, Qingyu; An, Dou; Yu, Wei; Tan, Zhengan; Yang, Xinyu

2016-06-17

Due to the advantage of avoiding upstream disturbance and voltage fluctuation from a power transmission system, Islanded Micro-Grids (IMG) have attracted much attention. In this paper, we first propose a novel self-sufficient Cyber-Physical System (CPS) supported by Internet of Things (IoT) techniques, namely "archipelago micro-grid (MG)", which integrates the power grid and sensor networks to make the grid operation effective and is comprised of multiple MGs while disconnected with the utility grid. The Electric Vehicles (EVs) are used to replace a portion of Conventional Vehicles (CVs) to reduce CO 2 emission and operation cost. Nonetheless, the intermittent nature and uncertainty of Renewable Energy Sources (RESs) remain a challenging issue in managing energy resources in the system. To address these issues, we formalize the optimal EV penetration problem as a two-stage Stochastic Optimal Penetration (SOP) model, which aims to minimize the emission and operation cost in the system. Uncertainties coming from RESs (e.g., wind, solar, and load demand) are considered in the stochastic model and random parameters to represent those uncertainties are captured by the Monte Carlo-based method. To enable the reasonable deployment of EVs in each MGs, we develop two scheduling schemes, namely Unlimited Coordinated Scheme (UCS) and Limited Coordinated Scheme (LCS), respectively. An extensive simulation study based on a modified 9 bus system with three MGs has been carried out to show the effectiveness of our proposed schemes. The evaluation data indicates that our proposed strategy can reduce both the environmental pollution created by CO 2 emissions and operation costs in UCS and LCS.

Towards Stochastic Optimization-Based Electric Vehicle Penetration in a Novel Archipelago Microgrid

PubMed Central

Yang, Qingyu; An, Dou; Yu, Wei; Tan, Zhengan; Yang, Xinyu

2016-01-01

Due to the advantage of avoiding upstream disturbance and voltage fluctuation from a power transmission system, Islanded Micro-Grids (IMG) have attracted much attention. In this paper, we first propose a novel self-sufficient Cyber-Physical System (CPS) supported by Internet of Things (IoT) techniques, namely “archipelago micro-grid (MG)”, which integrates the power grid and sensor networks to make the grid operation effective and is comprised of multiple MGs while disconnected with the utility grid. The Electric Vehicles (EVs) are used to replace a portion of Conventional Vehicles (CVs) to reduce CO2 emission and operation cost. Nonetheless, the intermittent nature and uncertainty of Renewable Energy Sources (RESs) remain a challenging issue in managing energy resources in the system. To address these issues, we formalize the optimal EV penetration problem as a two-stage Stochastic Optimal Penetration (SOP) model, which aims to minimize the emission and operation cost in the system. Uncertainties coming from RESs (e.g., wind, solar, and load demand) are considered in the stochastic model and random parameters to represent those uncertainties are captured by the Monte Carlo-based method. To enable the reasonable deployment of EVs in each MGs, we develop two scheduling schemes, namely Unlimited Coordinated Scheme (UCS) and Limited Coordinated Scheme (LCS), respectively. An extensive simulation study based on a modified 9 bus system with three MGs has been carried out to show the effectiveness of our proposed schemes. The evaluation data indicates that our proposed strategy can reduce both the environmental pollution created by CO2 emissions and operation costs in UCS and LCS. PMID:27322281

Novel Control Strategy for Multiple Run-of-the-River Hydro Power Plants to Provide Grid Ancillary Services

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanpurkar, Manish; Luo, Yusheng; Hovsapian, Rob

Hydropower plant (HPP) generation comprises a considerable portion of bulk electricity generation and is delivered with a low-carbon footprint. In fact, HPP electricity generation provides the largest share from renewable energy resources, which include wind and solar. Increasing penetration levels of wind and solar lead to a lower inertia on the electric grid, which poses stability challenges. In recent years, breakthroughs in energy storage technologies have demonstrated the economic and technical feasibility of extensive deployments of renewable energy resources on electric grids. If integrated with scalable, multi-time-step energy storage so that the total output can be controlled, multiple run-of-the-river (ROR)more » HPPs can be deployed. Although the size of a single energy storage system is much smaller than that of a typical reservoir, the ratings of storages and multiple ROR HPPs approximately equal the rating of a large, conventional HPP. This paper proposes cohesively managing multiple sets of energy storage systems distributed in different locations. This paper also describes the challenges associated with ROR HPP system architecture and operation.« less

Lighting the World: the first application of an open source, spatial electrification tool (OnSSET) on Sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Mentis, Dimitrios; Howells, Mark; Rogner, Holger; Korkovelos, Alexandros; Arderne, Christopher; Zepeda, Eduardo; Siyal, Shahid; Taliotis, Costantinos; Bazilian, Morgan; de Roo, Ad; Tanvez, Yann; Oudalov, Alexandre; Scholtz, Ernst

2017-08-01

In September 2015, the United Nations General Assembly adopted Agenda 2030, which comprises a set of 17 Sustainable Development Goals (SDGs) defined by 169 targets. ‘Ensuring access to affordable, reliable, sustainable and modern energy for all by 2030’ is the seventh goal (SDG7). While access to energy refers to more than electricity, the latter is the central focus of this work. According to the World Bank’s 2015 Global Tracking Framework, roughly 15% of the world’s population (or 1.1 billion people) lack access to electricity, and many more rely on poor quality electricity services. The majority of those without access (87%) reside in rural areas. This paper presents results of a geographic information systems approach coupled with open access data. We present least-cost electrification strategies on a country-by-country basis for Sub-Saharan Africa. The electrification options include grid extension, mini-grid and stand-alone systems for rural, peri-urban, and urban contexts across the economy. At low levels of electricity demand there is a strong penetration of standalone technologies. However, higher electricity demand levels move the favourable electrification option from stand-alone systems to mini grid and to grid extensions.

Method of grid generation

DOEpatents

Barnette, Daniel W.

2002-01-01

The present invention provides a method of grid generation that uses the geometry of the problem space and the governing relations to generate a grid. The method can generate a grid with minimized discretization errors, and with minimal user interaction. The method of the present invention comprises assigning grid cell locations so that, when the governing relations are discretized using the grid, at least some of the discretization errors are substantially zero. Conventional grid generation is driven by the problem space geometry; grid generation according to the present invention is driven by problem space geometry and by governing relations. The present invention accordingly can provide two significant benefits: more efficient and accurate modeling since discretization errors are minimized, and reduced cost grid generation since less human interaction is required.

Nearly Interactive Parabolized Navier-Stokes Solver for High Speed Forebody and Inlet Flows

NASA Technical Reports Server (NTRS)

Benson, Thomas J.; Liou, May-Fun; Jones, William H.; Trefny, Charles J.

2009-01-01

A system of computer programs is being developed for the preliminary design of high speed inlets and forebodies. The system comprises four functions: geometry definition, flow grid generation, flow solver, and graphics post-processor. The system runs on a dedicated personal computer using the Windows operating system and is controlled by graphical user interfaces written in MATLAB (The Mathworks, Inc.). The flow solver uses the Parabolized Navier-Stokes equations to compute millions of mesh points in several minutes. Sample two-dimensional and three-dimensional calculations are demonstrated in the paper.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, Y; Park, M; Kim, H

Purpose: This study aims to identify the feasibility of a novel cesium-iodine (CsI)-based flat-panel detector (FPD) for removing scatter radiation in diagnostic radiology. Methods: The indirect FPD comprises three layers: a substrate, scintillation, and thin-film-transistor (TFT) layer. The TFT layer has a matrix structure with pixels. There are ineffective dimensions on the TFT layer, such as the voltage and data lines; therefore, we devised a new FPD system having net-like lead in the substrate layer, matching the ineffective area, to block the scatter radiation so that only primary X-rays could reach the effective dimension.To evaluate the performance of this newmore » FPD system, we conducted a Monte Carlo simulation using MCNPX 2.6.0 software. Scatter fractions (SFs) were acquired using no grid, a parallel grid (8:1 grid ratio), and the new system, and the performances were compared.Two systems having different thicknesses of lead in the substrate layer—10 and 20μm—were simulated. Additionally, we examined the effects of different pixel sizes (153×153 and 163×163μm) on the image quality, while keeping the effective area of pixels constant (143×143μm). Results: In case of 10μm lead, the SFs of the new system (∼11%) were lower than those of the other system (∼27% with no grid, ∼16% with parallel grid) at 40kV. However, as the tube voltage increased, the SF of new system (∼19%) was higher than that of parallel grid (∼18%) at 120kV. In the case of 20μm lead, the SFs of the new system were lower than those of the other systems at all ranges of the tube voltage (40–120kV). Conclusion: The novel CsI-based FPD system for removing scatter radiation is feasible for improving the image contrast but must be optimized with respect to the lead thickness, considering the system’s purposes and the ranges of the tube voltage in diagnostic radiology. This study was supported by a grant(K1422651) from Institute of Health Science, Korea University.« less

Photovoltaic power converter system with a controller configured to actively compensate load harmonics

DOEpatents

de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

2008-12-16

Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

Systems and methods that generate height map models for efficient three dimensional reconstruction from depth information

DOEpatents

Frahm, Jan-Michael; Pollefeys, Marc Andre Leon; Gallup, David Robert

2015-12-08

Methods of generating a three dimensional representation of an object in a reference plane from a depth map including distances from a reference point to pixels in an image of the object taken from a reference point. Weights are assigned to respective voxels in a three dimensional grid along rays extending from the reference point through the pixels in the image based on the distances in the depth map from the reference point to the respective pixels, and a height map including an array of height values in the reference plane is formed based on the assigned weights. An n-layer height map may be constructed by generating a probabilistic occupancy grid for the voxels and forming an n-dimensional height map comprising an array of layer height values in the reference plane based on the probabilistic occupancy grid.

Optimum Aggregation and Control of Spatially Distributed Flexible Resources in Smart Grid

DOE PAGES

Bhattarai, Bishnu; Mendaza, Iker Diaz de Cerio; Myers, Kurt S.; ...

2017-03-24

This paper presents an algorithm to optimally aggregate spatially distributed flexible resources at strategic microgrid/smart-grid locations. The aggregation reduces a distribution network having thousands of nodes to an equivalent network with a few aggregated nodes, thereby enabling distribution system operators (DSOs) to make faster operational decisions. Moreover, the aggregation enables flexibility from small distributed flexible resources to be traded to different power and energy markets. A hierarchical control architecture comprising a combination of centralized and decentralized control approaches is proposed to practically deploy the aggregated flexibility. The proposed method serves as a great operational tool for DSOs to decide themore » exact amount of required flexibilities from different network section(s) for solving grid constraint violations. The effectiveness of the proposed method is demonstrated through simulation of three operational scenarios in a real low voltage distribution system having high penetrations of electric vehicles and heat pumps. Finally, the simulation results demonstrated that the aggregation helps DSOs not only in taking faster operational decisions, but also in effectively utilizing the available flexibility.« less

Optimum Aggregation and Control of Spatially Distributed Flexible Resources in Smart Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattarai, Bishnu; Mendaza, Iker Diaz de Cerio; Myers, Kurt S.

This paper presents an algorithm to optimally aggregate spatially distributed flexible resources at strategic microgrid/smart-grid locations. The aggregation reduces a distribution network having thousands of nodes to an equivalent network with a few aggregated nodes, thereby enabling distribution system operators (DSOs) to make faster operational decisions. Moreover, the aggregation enables flexibility from small distributed flexible resources to be traded to different power and energy markets. A hierarchical control architecture comprising a combination of centralized and decentralized control approaches is proposed to practically deploy the aggregated flexibility. The proposed method serves as a great operational tool for DSOs to decide themore » exact amount of required flexibilities from different network section(s) for solving grid constraint violations. The effectiveness of the proposed method is demonstrated through simulation of three operational scenarios in a real low voltage distribution system having high penetrations of electric vehicles and heat pumps. Finally, the simulation results demonstrated that the aggregation helps DSOs not only in taking faster operational decisions, but also in effectively utilizing the available flexibility.« less

High-Density Stretchable Electrode Grids for Chronic Neural Recording

PubMed Central

Tybrandt, Klas; Khodagholy, Dion; Dielacher, Bernd; Stauffer, Flurin; Renz, Aline F.; Buzsáki, György; Vörös, János

2018-01-01

Electrical interfacing with neural tissue is key to advancing diagnosis and therapies for neurological disorders, as well as providing detailed information about neural signals. A challenge for creating long-term stable interfaces between electronics and neural tissue is the huge mechanical mismatch between the systems. So far, materials and fabrication processes have restricted the development of soft electrode grids able to combine high performance, long-term stability, and high electrode density, aspects all essential for neural interfacing. Here, this challenge is addressed by developing a soft, high-density, stretchable electrode grid based on an inert, high-performance composite material comprising gold-coated titanium dioxide nanowires embedded in a silicone matrix. The developed grid can resolve high spatiotemporal neural signals from the surface of the cortex in freely moving rats with stable neural recording quality and preserved electrode signal coherence during 3 months of implantation. Due to its flexible and stretchable nature, it is possible to minimize the size of the craniotomy required for placement, further reducing the level of invasiveness. The material and device technology presented herein have potential for a wide range of emerging biomedical applications. PMID:29488263

Extending the Fermi-LAT Data Processing Pipeline to the Grid

NASA Astrophysics Data System (ADS)

Zimmer, S.; Arrabito, L.; Glanzman, T.; Johnson, T.; Lavalley, C.; Tsaregorodtsev, A.

2012-12-01

The Data Handling Pipeline (“Pipeline”) has been developed for the Fermi Gamma-Ray Space Telescope (Fermi) Large Area Telescope (LAT) which launched in June 2008. Since then it has been in use to completely automate the production of data quality monitoring quantities, reconstruction and routine analysis of all data received from the satellite and to deliver science products to the collaboration and the Fermi Science Support Center. Aside from the reconstruction of raw data from the satellite (Level 1), data reprocessing and various event-level analyses are also reasonably heavy loads on the pipeline and computing resources. These other loads, unlike Level 1, can run continuously for weeks or months at a time. In addition it receives heavy use in performing production Monte Carlo tasks. In daily use it receives a new data download every 3 hours and launches about 2000 jobs to process each download, typically completing the processing of the data before the next download arrives. The need for manual intervention has been reduced to less than 0.01% of submitted jobs. The Pipeline software is written almost entirely in Java and comprises several modules. The software comprises web-services that allow online monitoring and provides charts summarizing work flow aspects and performance information. The server supports communication with several batch systems such as LSF and BQS and recently also Sun Grid Engine and Condor. This is accomplished through dedicated job control services that for Fermi are running at SLAC and the other computing site involved in this large scale framework, the Lyon computing center of IN2P3. While being different in the logic of a task, we evaluate a separate interface to the Dirac system in order to communicate with EGI sites to utilize Grid resources, using dedicated Grid optimized systems rather than developing our own. More recently the Pipeline and its associated data catalog have been generalized for use by other experiments, and are currently being used by the Enriched Xenon Observatory (EXO), Cryogenic Dark Matter Search (CDMS) experiments as well as for Monte Carlo simulations for the future Cherenkov Telescope Array (CTA).

Multigrid approaches to non-linear diffusion problems on unstructured meshes

NASA Technical Reports Server (NTRS)

Mavriplis, Dimitri J.; Bushnell, Dennis M. (Technical Monitor)

2001-01-01

The efficiency of three multigrid methods for solving highly non-linear diffusion problems on two-dimensional unstructured meshes is examined. The three multigrid methods differ mainly in the manner in which the nonlinearities of the governing equations are handled. These comprise a non-linear full approximation storage (FAS) multigrid method which is used to solve the non-linear equations directly, a linear multigrid method which is used to solve the linear system arising from a Newton linearization of the non-linear system, and a hybrid scheme which is based on a non-linear FAS multigrid scheme, but employs a linear solver on each level as a smoother. Results indicate that all methods are equally effective at converging the non-linear residual in a given number of grid sweeps, but that the linear solver is more efficient in cpu time due to the lower cost of linear versus non-linear grid sweeps.

Wafer-fused semiconductor radiation detector

DOEpatents

Lee, Edwin Y.; James, Ralph B.

2002-01-01

Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

Axially shaped channel and integral flow trippers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowther, R.L.; Johansson, E.B.; Matzner, B.

1988-06-07

A fuel assembly is described comprising fuel rods positioned in spaced array by upper and lower tie-plates, an open ended flow channel surrounding the array for conducting coolant upward between a lower support plate having coolant communicated thereto to an upper support grid having a steam/water outlet communicated thereto. The flow channel surrounds the array for conducting coolant about the fuel rods. The open ended channel has a polygon shaped cross section with the channel constituting a closed conduit with flat side sections connected at corners to form the enclosed conduit; means separate from the channel for connecting the uppermore » and lower tie-plates together and maintaining the fuel rods in spaced array independent of the flow channel. The improvement in the flow channel comprises tapered side walls. The tapered side walls extend from an average thick cross section adjacent the lower support plate to an average thin cross section adjacent the upper core grid whereby the channel is reduced in thickness adjacent the upper core grid to correspond with the reduced pressure adjacent the upper core grid.« less

Axially shaped channel and integral flow trippers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowther, R.L. Jr.; Johansson, E.B.; Matzner, B.

1992-02-11

This patent describes a fuel assembly. It comprises: fuel rods positioned in spaced array by upper and lower tie-plates, and open ended flow channel surrounding the array for conducting coolant upward between a lower support plate having coolant communicated thereto to an upper support grid having a steam/water outlet communicated thereto. The flow channel surrounding the array for conducting coolant about the fuel rods; the open ended channel having a polygon shaped cross section with the channel constituting a closed conduit with flat side sections connected at corners to form the enclosed conduit; means separate from the channel for connectingmore » the upper and lower tie-plates together and maintaining the fuel rods in spaced array independent of the flow channel, the improvement in the flow channel comprising tapered side walls, the tapered side walls extending from an average thick cross section adjacent the lower support plate to an average thin cross section adjacent the upper core grid whereby the channel is reduced in thickness adjacent the upper core grid to correspond with the reduced pressure adjacent the upper core grid.« less

Emergency heat removal system for a nuclear reactor

DOEpatents

Dunckel, Thomas L.

1976-01-01

A heat removal system for nuclear reactors serving as a supplement to an Emergency Core Cooling System (ECCS) during a Loss of Coolant Accident (LOCA) comprises a plurality of heat pipes having one end in heat transfer relationship with either the reactor pressure vessel, the core support grid structure or other in-core components and the opposite end located in heat transfer relationship with a heat exchanger having heat transfer fluid therein. The heat exchanger is located external to the pressure vessel whereby excessive core heat is transferred from the above reactor components and dissipated within the heat exchanger fluid.

High-Density Stretchable Electrode Grids for Chronic Neural Recording.

PubMed

Tybrandt, Klas; Khodagholy, Dion; Dielacher, Bernd; Stauffer, Flurin; Renz, Aline F; Buzsáki, György; Vörös, János

2018-04-01

Electrical interfacing with neural tissue is key to advancing diagnosis and therapies for neurological disorders, as well as providing detailed information about neural signals. A challenge for creating long-term stable interfaces between electronics and neural tissue is the huge mechanical mismatch between the systems. So far, materials and fabrication processes have restricted the development of soft electrode grids able to combine high performance, long-term stability, and high electrode density, aspects all essential for neural interfacing. Here, this challenge is addressed by developing a soft, high-density, stretchable electrode grid based on an inert, high-performance composite material comprising gold-coated titanium dioxide nanowires embedded in a silicone matrix. The developed grid can resolve high spatiotemporal neural signals from the surface of the cortex in freely moving rats with stable neural recording quality and preserved electrode signal coherence during 3 months of implantation. Due to its flexible and stretchable nature, it is possible to minimize the size of the craniotomy required for placement, further reducing the level of invasiveness. The material and device technology presented herein have potential for a wide range of emerging biomedical applications. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Domain decomposition by the advancing-partition method for parallel unstructured grid generation

NASA Technical Reports Server (NTRS)

Banihashemi, legal representative, Soheila (Inventor); Pirzadeh, Shahyar Z. (Inventor)

2012-01-01

In a method for domain decomposition for generating unstructured grids, a surface mesh is generated for a spatial domain. A location of a partition plane dividing the domain into two sections is determined. Triangular faces on the surface mesh that intersect the partition plane are identified. A partition grid of tetrahedral cells, dividing the domain into two sub-domains, is generated using a marching process in which a front comprises only faces of new cells which intersect the partition plane. The partition grid is generated until no active faces remain on the front. Triangular faces on each side of the partition plane are collected into two separate subsets. Each subset of triangular faces is renumbered locally and a local/global mapping is created for each sub-domain. A volume grid is generated for each sub-domain. The partition grid and volume grids are then merged using the local-global mapping.

Multidimensional Environmental Data Resource Brokering on Computational Grids and Scientific Clouds

NASA Astrophysics Data System (ADS)

Montella, Raffaele; Giunta, Giulio; Laccetti, Giuliano

Grid computing has widely evolved over the past years, and its capabilities have found their way even into business products and are no longer relegated to scientific applications. Today, grid computing technology is not restricted to a set of specific grid open source or industrial products, but rather it is comprised of a set of capabilities virtually within any kind of software to create shared and highly collaborative production environments. These environments are focused on computational (workload) capabilities and the integration of information (data) into those computational capabilities. An active grid computing application field is the fully virtualization of scientific instruments in order to increase their availability and decrease operational and maintaining costs. Computational and information grids allow to manage real-world objects in a service-oriented way using industrial world-spread standards.

Influence of high-resolution surface databases on the modeling of local atmospheric circulation systems

NASA Astrophysics Data System (ADS)

Paiva, L. M. S.; Bodstein, G. C. R.; Pimentel, L. C. G.

2013-12-01

Large-eddy simulations are performed using the Advanced Regional Prediction System (ARPS) code at horizontal grid resolutions as fine as 300 m to assess the influence of detailed and updated surface databases on the modeling of local atmospheric circulation systems of urban areas with complex terrain. Applications to air pollution and wind energy are sought. These databases are comprised of 3 arc-sec topographic data from the Shuttle Radar Topography Mission, 10 arc-sec vegetation type data from the European Space Agency (ESA) GlobCover Project, and 30 arc-sec Leaf Area Index and Fraction of Absorbed Photosynthetically Active Radiation data from the ESA GlobCarbon Project. Simulations are carried out for the Metropolitan Area of Rio de Janeiro using six one-way nested-grid domains that allow the choice of distinct parametric models and vertical resolutions associated to each grid. ARPS is initialized using the Global Forecasting System with 0.5°-resolution data from the National Center of Environmental Prediction, which is also used every 3 h as lateral boundary condition. Topographic shading is turned on and two soil layers with depths of 0.01 and 1.0 m are used to compute the soil temperature and moisture budgets in all runs. Results for two simulated runs covering the period from 6 to 7 September 2007 are compared to surface and upper-air observational data to explore the dependence of the simulations on initial and boundary conditions, topographic and land-use databases and grid resolution. Our comparisons show overall good agreement between simulated and observed data and also indicate that the low resolution of the 30 arc-sec soil database from United States Geological Survey, the soil moisture and skin temperature initial conditions assimilated from the GFS analyses and the synoptic forcing on the lateral boundaries of the finer grids may affect an adequate spatial description of the meteorological variables.

Method for the depth corrected detection of ionizing events from a co-planar grids sensor

DOEpatents

De Geronimo, Gianluigi [Syosset, NY; Bolotnikov, Aleksey E [South Setauket, NY; Carini, Gabriella [Port Jefferson, NY

2009-05-12

A method for the detection of ionizing events utilizing a co-planar grids sensor comprising a semiconductor substrate, cathode electrode, collecting grid and non-collecting grid. The semiconductor substrate is sensitive to ionizing radiation. A voltage less than 0 Volts is applied to the cathode electrode. A voltage greater than the voltage applied to the cathode is applied to the non-collecting grid. A voltage greater than the voltage applied to the non-collecting grid is applied to the collecting grid. The collecting grid and the non-collecting grid are summed and subtracted creating a sum and difference respectively. The difference and sum are divided creating a ratio. A gain coefficient factor for each depth (distance between the ionizing event and the collecting grid) is determined, whereby the difference between the collecting electrode and the non-collecting electrode multiplied by the corresponding gain coefficient is the depth corrected energy of an ionizing event. Therefore, the energy of each ionizing event is the difference between the collecting grid and the non-collecting grid multiplied by the corresponding gain coefficient. The depth of the ionizing event can also be determined from the ratio.

Influence of high-resolution surface databases on the modeling of local atmospheric circulation systems

NASA Astrophysics Data System (ADS)

Paiva, L. M. S.; Bodstein, G. C. R.; Pimentel, L. C. G.

2014-08-01

Large-eddy simulations are performed using the Advanced Regional Prediction System (ARPS) code at horizontal grid resolutions as fine as 300 m to assess the influence of detailed and updated surface databases on the modeling of local atmospheric circulation systems of urban areas with complex terrain. Applications to air pollution and wind energy are sought. These databases are comprised of 3 arc-sec topographic data from the Shuttle Radar Topography Mission, 10 arc-sec vegetation-type data from the European Space Agency (ESA) GlobCover project, and 30 arc-sec leaf area index and fraction of absorbed photosynthetically active radiation data from the ESA GlobCarbon project. Simulations are carried out for the metropolitan area of Rio de Janeiro using six one-way nested-grid domains that allow the choice of distinct parametric models and vertical resolutions associated to each grid. ARPS is initialized using the Global Forecasting System with 0.5°-resolution data from the National Center of Environmental Prediction, which is also used every 3 h as lateral boundary condition. Topographic shading is turned on and two soil layers are used to compute the soil temperature and moisture budgets in all runs. Results for two simulated runs covering three periods of time are compared to surface and upper-air observational data to explore the dependence of the simulations on initial and boundary conditions, grid resolution, topographic and land-use databases. Our comparisons show overall good agreement between simulated and observational data, mainly for the potential temperature and the wind speed fields, and clearly indicate that the use of high-resolution databases improves significantly our ability to predict the local atmospheric circulation.

Methods and apparatus of analyzing electrical power grid data

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 interestmore » in the large-scale data set.« less

The Parallel System for Integrating Impact Models and Sectors (pSIMS)

NASA Technical Reports Server (NTRS)

Elliott, Joshua; Kelly, David; Chryssanthacopoulos, James; Glotter, Michael; Jhunjhnuwala, Kanika; Best, Neil; Wilde, Michael; Foster, Ian

2014-01-01

We present a framework for massively parallel climate impact simulations: the parallel System for Integrating Impact Models and Sectors (pSIMS). This framework comprises a) tools for ingesting and converting large amounts of data to a versatile datatype based on a common geospatial grid; b) tools for translating this datatype into custom formats for site-based models; c) a scalable parallel framework for performing large ensemble simulations, using any one of a number of different impacts models, on clusters, supercomputers, distributed grids, or clouds; d) tools and data standards for reformatting outputs to common datatypes for analysis and visualization; and e) methodologies for aggregating these datatypes to arbitrary spatial scales such as administrative and environmental demarcations. By automating many time-consuming and error-prone aspects of large-scale climate impacts studies, pSIMS accelerates computational research, encourages model intercomparison, and enhances reproducibility of simulation results. We present the pSIMS design and use example assessments to demonstrate its multi-model, multi-scale, and multi-sector versatility.

Duke Engineering explores huge African Power Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newman, P.

1994-10-14

Duke Engineering & Services and the African Republic of Uganda have entered into a memorandum of understanding to explore the feasibility of installing one or more hydropower plants along the Nile River and building a 2,000 mile transmission line through southern Africa. The project`s participants say they envision a southern African electricity grid connecting all countries in the region. A team comprised of officials from DE&S, Edlow and SAD-ELEC will conduct a six-month, two-part study on the feasibility of linking the existing grid system in the region. The first part of the study will look at the feasibility of installingmore » one or more independent hydropower plants along the Nile and other rivers in Uganda. The second part will explore the design, construction and operation of a transmission system to interconnect Uganda, through neighboring countries to the south and east, to the Republic of South Africa. The site for the proposed hydroelectric plant will determine the route of the transmission line.« less

NEUTRONIC REACTORS

DOEpatents

Anderson, J.B.

1960-01-01

A reactor is described which comprises a tank, a plurality of coaxial steel sleeves in the tank, a mass of water in the tank, and wire grids in abutting relationship within a plurality of elongated parallel channels within the steel sleeves, the wire being provided with a plurality of bends in the same plane forming adjacent parallel sections between bends, and the sections of adjacent grids being normally disposed relative to each other.

Mapping near-surface air temperature, pressure, relative humidity and wind speed over Mainland China with high spatiotemporal resolution

NASA Astrophysics Data System (ADS)

Li, Tao; Zheng, Xiaogu; Dai, Yongjiu; Yang, Chi; Chen, Zhuoqi; Zhang, Shupeng; Wu, Guocan; Wang, Zhonglei; Huang, Chengcheng; Shen, Yan; Liao, Rongwei

2014-09-01

As part of a joint effort to construct an atmospheric forcing dataset for mainland China with high spatiotemporal resolution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km×1 km. The approach comprises two steps: (1) fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; (2) apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over mainland China. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.

Properties of a Variable-Delay Polarization Modulator

NASA Technical Reports Server (NTRS)

Chuss, David T.; Wollack, Edward J.; Henry, Ross; Hui, Howard; Juarez, Aaron J.; Krenjy, Megan; Moseley, Harvey; Novak, Giles

2011-01-01

We investigate the polarization modulation properties of a variable-delay polarization modulator (VPM). The VPM modulates polarization via a variable separation between a polarizing grid and a parallel mirror. We find that in the limit where the wavelength is much larger than the diameter of the metal wires that comprise the grid, the phase delay derived from the geometric separation between the mirror and the grid is sufficient to characterize the device. However, outside of this range, additional parameters describing the polarizing grid geometry must be included to fully characterize the modulator response. In this paper, we report test results of a VPM at wavelengths of 350 micron and 3 mm. Electromagnetic simulations of wire grid polarizers were performed and are summarized using a simple circuit model that incorporates the loss and polarization properties of the device.

Stability Assessment of a System Comprising a Single Machine and Inverter with Scalable Ratings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Brian B; Lin, Yashen; Gevorgian, Vahan

Synchronous machines have traditionally acted as the foundation of large-scale electrical infrastructures and their physical properties have formed the cornerstone of system operations. However, with the increased integration of distributed renewable resources and energy-storage technologies, there is a need to systematically acknowledge the dynamics of power-electronics inverters - the primary energy-conversion interface in such systems - in all aspects of modeling, analysis, and control of the bulk power network. In this paper, we assess the properties of coupled machine-inverter systems by studying an elementary system comprised of a synchronous generator, three-phase inverter, and a load. The inverter model is formulatedmore » such that its power rating can be scaled continuously across power levels while preserving its closed-loop response. Accordingly, the properties of the machine-inverter system can be assessed for varying ratios of machine-to-inverter power ratings. After linearizing the model and assessing its eigenvalues, we show that system stability is highly dependent on the inverter current controller and machine exciter, thus uncovering a key concern with mixed machine-inverter systems and motivating the need for next-generation grid-stabilizing inverter controls.« less

PULSE AMPLIFIER

DOEpatents

Johnstone, C.W.

1958-06-17

The improvement of pulse amplifiers used with scintillation detectors is described. The pulse amplifier circuit has the advantage of reducing the harmful effects of overloading cause by large signal inputs. In general the pulse amplifier circuit comprises two amplifier tubes with the input pulses applied to one amplifier grid and coupled to the second amplifier tube through a common cathode load. The output of the second amplifier is coupled from the plate circuit to a cathode follower tube grid and a diode tube in connected from grid to cathode of the cathode follower tube. Degenerative feedback is provided in the second amplifier by coupling a signal from the cathode follower cathode to the second amplifier grid. The circuit proqides moderate gain stability, and overload protection for subsequent pulse circuits.

Intelligent sensor and controller framework for the power grid

DOEpatents

Akyol, Bora A.; Haack, Jereme Nathan; Craig, Jr., Philip Allen; Tews, Cody William; Kulkarni, Anand V.; Carpenter, Brandon J.; Maiden, Wendy M.; Ciraci, Selim

2015-07-28

Disclosed below are representative embodiments of methods, apparatus, and systems for monitoring and using data in an electric power grid. For example, one disclosed embodiment comprises a sensor for measuring an electrical characteristic of a power line, electrical generator, or electrical device; a network interface; a processor; and one or more computer-readable storage media storing computer-executable instructions. In this embodiment, the computer-executable instructions include instructions for implementing an authorization and authentication module for validating a software agent received at the network interface; instructions for implementing one or more agent execution environments for executing agent code that is included with the software agent and that causes data from the sensor to be collected; and instructions for implementing an agent packaging and instantiation module for storing the collected data in a data container of the software agent and for transmitting the software agent, along with the stored data, to a next destination.

Intelligent sensor and controller framework for the power grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akyol, Bora A.; Haack, Jereme Nathan; Craig, Jr., Philip Allen

Disclosed below are representative embodiments of methods, apparatus, and systems for monitoring and using data in an electric power grid. For example, one disclosed embodiment comprises a sensor for measuring an electrical characteristic of a power line, electrical generator, or electrical device; a network interface; a processor; and one or more computer-readable storage media storing computer-executable instructions. In this embodiment, the computer-executable instructions include instructions for implementing an authorization and authentication module for validating a software agent received at the network interface; instructions for implementing one or more agent execution environments for executing agent code that is included with themore » software agent and that causes data from the sensor to be collected; and instructions for implementing an agent packaging and instantiation module for storing the collected data in a data container of the software agent and for transmitting the software agent, along with the stored data, to a next destination.« less

Grid Stiffened Structure Analysis Tool

NASA Technical Reports Server (NTRS)

1999-01-01

The Grid Stiffened Analysis Tool contract is contract performed by Boeing under NASA purchase order H30249D. The contract calls for a "best effort" study comprised of two tasks: (1) Create documentation for a composite grid-stiffened structure analysis tool, in the form of a Microsoft EXCEL spread sheet, that was developed by originally at Stanford University and later further developed by the Air Force, and (2) Write a program that functions as a NASTRAN pre-processor to generate an FEM code for grid-stiffened structure. In performing this contract, Task 1 was given higher priority because it enables NASA to make efficient use of a unique tool they already have; Task 2 was proposed by Boeing because it also would be beneficial to the analysis of composite grid-stiffened structures, specifically in generating models for preliminary design studies. The contract is now complete, this package includes copies of the user's documentation for Task 1 and a CD ROM & diskette with an electronic copy of the user's documentation and an updated version of the "GRID 99" spreadsheet.

ELECTRONIC MULTIPLIER CIRCUIT

DOEpatents

Thomas, R.E.

1959-08-25

An electronic multiplier circuit is described in which an output voltage having an amplitude proportional to the product or quotient of the input signals is accomplished in a novel manner which facilitates simplicity of circuit construction and a high degree of accuracy in accomplishing the multiplying and dividing function. The circuit broadly comprises a multiplier tube in which the plate current is proportional to the voltage applied to a first control grid multiplied by the difference between voltage applied to a second control grid and the voltage applied to the first control grid. Means are provided to apply a first signal to be multiplied to the first control grid together with means for applying the sum of the first signal to be multiplied and a second signal to be multiplied to the second control grid whereby the plate current of the multiplier tube is proportional to the product of the first and second signals to be multiplied.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawder, Matthew T.; Viswanathan, Vilayanur V.; Subramanian, Venkat R.

The growth of intermittent solar power has developed a need for energy storage systems in order to decouple generation and supply of energy. Microgrid (MG) systems comprising of solar arrays with battery energy storage studied in this paper desire high levels of autonomy, seeking to meet desired demand at all times. Large energy storage capacity is required for high levels of autonomy, but much of this expensive capacity goes unused for a majority of the year due to seasonal fluctuations of solar generation. In this paper, a model-based study of MGs comprised of solar generation and battery storage shows themore » relationship between system autonomy and battery utilization applied to multiple demand cases using a single particle battery model (SPM). The SPM allows for more accurate state-of-charge and utilization estimation of the battery than previous studies of renewably powered systems that have used empirical models. The increased accuracy of battery state estimation produces a better assessment of system performance. Battery utilization will depend on the amount of variation in solar insolation as well as the type of demand required by the MG. Consumers must balance autonomy and desired battery utilization of a system within the needs of their grid.« less

Balancing autonomy and utilization of solar power and battery storage for demand based microgrids

NASA Astrophysics Data System (ADS)

Lawder, Matthew T.; Viswanathan, Vilayanur; Subramanian, Venkat R.

2015-04-01

The growth of intermittent solar power has developed a need for energy storage systems in order to decouple generation and supply of energy. Microgrid (MG) systems comprising of solar arrays with battery energy storage studied in this paper desire high levels of autonomy, seeking to meet desired demand at all times. Large energy storage capacity is required for high levels of autonomy, but much of this expensive capacity goes unused for a majority of the year due to seasonal fluctuations of solar generation. In this paper, a model-based study of MGs comprised of solar generation and battery storage shows the relationship between system autonomy and battery utilization applied to multiple demand cases using a single particle battery model (SPM). The SPM allows for more accurate state-of-charge and utilization estimation of the battery than previous studies of renewably powered systems that have used empirical models. The increased accuracy of battery state estimation produces a better assessment of system performance. Battery utilization will depend on the amount of variation in solar insolation as well as the type of demand required by the MG. Consumers must balance autonomy and desired battery utilization of a system within the needs of their grid.

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

DOEpatents

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-01-01

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

DOEpatents

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-09-05

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Evaluating the performance of a 50 kilowatt grid-connected photovoltaic system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, B.H.; Muknahallipatn, S.; Cupal, J.J.

A 50-kilowatt solar photovoltaic (PV) system was built at the University of Wyoming (UW) in 1996. The system comprises of three sub-systems. The first sub-system, a 10 kW roof-integrated system is located on the roof of the Engineering Building. The second sub-system is a 5 kW rack-mounted, ballasted PV system located on another part of the roof. The third sub-system is a 35 kW shade structure and is located adjacent to the university's football stadium. The three sub-systems differ in their design strategy since each is being used for research and education at the university. Each sub-system, being located atmore » some distance away from one another, supplies a different part of the campus grid. Efforts are continuing for setting up a central monitoring system, which will receive data remotely from all locations. A part of this monitoring system is complete. The system as configured provides a great deal of flexibility, which is in turn demanded by the variety of signal types measured at each installation. Each installation requires measurement of multiple dc and ac voltages and currents and one slowly varying voltage (proportional to solar insolation). The simultaneous sampling, fast sample rate, and lowpass signal conditioning allow for accurate measurement of power factor and total harmonic distortion of the inverter outputs. Panel and inverter efficiencies can be determined via simultaneous DC and AC measurements. These performance monitors provide the essential data for characterization of the PV effect at the grid input, and enable the use of intelligent power factor correction and harmonic filtering. Monitoring of the system shows that the total harmonic distortion present in the ac power output is at or below the acceptable limit as recommended by IEEE 519-1992. The harmonic distortion worsens when the ac power reaches more than 3.8 kW. A number of reliability problems with PV modules and inverters have delayed full functionality of the system.« less

GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 2: User's manual and program listing

NASA Technical Reports Server (NTRS)

Bailey, R. T.; Shih, T. I.-P.; Nguyen, H. L.; Roelke, R. J.

1990-01-01

An efficient computer program, called GRID2D/3D, was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no modifications are needed in the grid generation part of the program. The theory and method used in GRID2D/3D is described.

GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 1: Theory and method

NASA Technical Reports Server (NTRS)

Shih, T. I.-P.; Bailey, R. T.; Nguyen, H. L.; Roelke, R. J.

1990-01-01

An efficient computer program, called GRID2D/3D was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no modifications are needed in the grid generation part of the program. This technical memorandum describes the theory and method used in GRID2D/3D.

Phase 1 of the First Solar Small Power System Experiment (experimental System No. 1). Volume 1: Technical Studies for Solar Point-focusing, Distributed Collector System, with Energy Conversion at the Collector, Category C

NASA Technical Reports Server (NTRS)

Clark, T. B. (Editor)

1979-01-01

The technical and economic feasibility of a solar electric power plant for a small community is evaluated and specific system designs for development and demonstration are selected. All systems investigated are defined as point focusing, distributed receiver concepts, with energy conversion at the collector. The preferred system is comprised of multiple parabolic dish concentrators employing Stirling cycle engines for power conversion. The engine, AC generator, cavity receiver, and integral sodium pool boiler/heat transport system are combined in a single package and mounted at the focus of each concentrator. The output of each concentrator is collected by a conventional electrical distribution system which permits grid-connected or stand-alone operation, depending on the storage system selected.

Stability Assessment of a System Comprising a Single Machine and Inverter with Scalable Ratings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Brian B; Lin, Yashen; Gevorgian, Vahan

From the inception of power systems, synchronous machines have acted as the foundation of large-scale electrical infrastructures and their physical properties have formed the cornerstone of system operations. However, power electronics interfaces are playing a growing role as they are the primary interface for several types of renewable energy sources and storage technologies. As the role of power electronics in systems continues to grow, it is crucial to investigate the properties of bulk power systems in low inertia settings. In this paper, we assess the properties of coupled machine-inverter systems by studying an elementary system comprised of a synchronous generator,more » three-phase inverter, and a load. Furthermore, the inverter model is formulated such that its power rating can be scaled continuously across power levels while preserving its closed-loop response. Accordingly, the properties of the machine-inverter system can be assessed for varying ratios of machine-to-inverter power ratings and, hence, differing levels of inertia. After linearizing the model and assessing its eigenvalues, we show that system stability is highly dependent on the interaction between the inverter current controller and machine exciter, thus uncovering a key concern with mixed machine-inverter systems and motivating the need for next-generation grid-stabilizing inverter controls.« less

Simulation studies on multi-mode heat transfer from an open cavity with a flush-mounted discrete heat source

NASA Astrophysics Data System (ADS)

Gururaja Rao, C.; Nagabhushana Rao, V.; Krishna Das, C.

2008-04-01

Prominent results of a simulation study on conjugate convection with surface radiation from an open cavity with a traversable flush mounted discrete heat source in the left wall are presented in this paper. The open cavity is considered to be of fixed height but with varying spacing between the legs. The position of the heat source is varied along the left leg of the cavity. The governing equations for temperature distribution along the cavity are obtained by making energy balance between heat generated, conducted, convected and radiated. Radiation terms are tackled using radiosity-irradiation formulation, while the view factors, therein, are evaluated using the crossed-string method of Hottel. The resulting non-linear partial differential equations are converted into algebraic form using finite difference formulation and are subsequently solved by Gauss Seidel iterative technique. An optimum grid system comprising 111 grids along the legs of the cavity, with 30 grids in the heat source and 31 grids across the cavity has been used. The effects of various parameters, such as surface emissivity, convection heat transfer coefficient, aspect ratio and thermal conductivity on the important results, including local temperature distribution along the cavity, peak temperature in the left and right legs of the cavity and relative contributions of convection and radiation to heat dissipation in the cavity, are studied in great detail.

Solar cells having integral collector grids

NASA Technical Reports Server (NTRS)

Evans, J. C., Jr. (Inventor)

1978-01-01

A heterojunction or Schottky barrier photovoltaic device is described, comprising a conductive base metal layer. A back surface field region was formed at the interface between the device and the base metal layer, a transparent, conductive mixed metal oxide layer in integral contact with the n-type layer of the heterojunction or Schottky barrier device. A metal alloy grid network was included. An insulating layer prevented electrical contact between the conductive metal base layer and the transparent, conductive metal oxide layer.

Satellite power system concept development and evaluation program. Volume 2: System definition

NASA Technical Reports Server (NTRS)

1981-01-01

The system level results of the system definition studies performed by NASA as a part of the Department of Energy/NASA satellite power system concept development and evaluation program are summarized. System requirements and guidelines are discussed as well as the major elements that comprise the reference system and its design options. Alternative system approaches including different system sizes, solid state amplifier (microwave) concepts, and laser power transmission system cost summaries are reviewed. An overview of the system analysis and planning efforts is included. The overall study led to the conclusion that the reference satellite power system concept is a feasible baseload source of electrical power and, within the assumed guidelines, the minimum cost per kilowatt is achieved at the maximum output of 5 gigawatts to the utility grid. Major unresolved technical issues include maximum allowable microwave power density in the ionosphere and performance/mass characteristics of laser power transmission systems.

High power gas laser amplifier

DOEpatents

Leland, Wallace T.; Stratton, Thomas F.

1981-01-01

A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

Optimizing Data Management in Grid Environments

NASA Astrophysics Data System (ADS)

Zissimos, Antonis; Doka, Katerina; Chazapis, Antony; Tsoumakos, Dimitrios; Koziris, Nectarios

Grids currently serve as platforms for numerous scientific as well as business applications that generate and access vast amounts of data. In this paper, we address the need for efficient, scalable and robust data management in Grid environments. We propose a fully decentralized and adaptive mechanism comprising of two components: A Distributed Replica Location Service (DRLS) and a data transfer mechanism called GridTorrent. They both adopt Peer-to-Peer techniques in order to overcome performance bottlenecks and single points of failure. On one hand, DRLS ensures resilience by relying on a Byzantine-tolerant protocol and is able to handle massive concurrent requests even during node churn. On the other hand, GridTorrent allows for maximum bandwidth utilization through collaborative sharing among the various data providers and consumers. The proposed integrated architecture is completely backwards-compatible with already deployed Grids. To demonstrate these points, experiments have been conducted in LAN as well as WAN environments under various workloads. The evaluation shows that our scheme vastly outperforms the conventional mechanisms in both efficiency (up to 10 times faster) and robustness in case of failures and flash crowd instances.

Microgravity

NASA Image and Video Library

2004-04-15

Test cells comprise specimen sand contained in a latex membrane (with a grid pattern for CCD cameras) between metal end plates and housed in a water-filled Lexan jacket. Experiment flown on STS-79 and STS-89. Principal Investigator: Dr. Stein Sture.

Architecture and Initial Development of a Knowledge-as-a-Service Activator for Computable Knowledge Objects for Health.

PubMed

Flynn, Allen J; Boisvert, Peter; Gittlen, Nate; Gross, Colin; Iott, Brad; Lagoze, Carl; Meng, George; Friedman, Charles P

2018-01-01

The Knowledge Grid (KGrid) is a research and development program toward infrastructure capable of greatly decreasing latency between the publication of new biomedical knowledge and its widespread uptake into practice. KGrid comprises digital knowledge objects, an online Library to store them, and an Activator that uses them to provide Knowledge-as-a-Service (KaaS). KGrid's Activator enables computable biomedical knowledge, held in knowledge objects, to be rapidly deployed at Internet-scale in cloud computing environments for improved health. Here we present the Activator, its system architecture and primary functions.

Controllable Grid Interface Test System | Energy Systems Integration

Science.gov Websites

Facility | NREL Controllable Grid Interface Test System Controllable Grid Interface Test System NREL's controllable grid interface (CGI) test system can reduce certification testing time and costs grid interface is the first test facility in the United States that has fault simulation capabilities

Optical beam forming techniques for phased array antennas

NASA Technical Reports Server (NTRS)

Wu, Te-Kao; Chandler, C.

1993-01-01

Conventional phased array antennas using waveguide or coax for signal distribution are impractical for large scale implementation on satellites or spacecraft because they exhibit prohibitively large system size, heavy weight, high attenuation loss, limited bandwidth, sensitivity to electromagnetic interference (EMI) temperature drifts and phase instability. However, optical beam forming systems are smaller, lighter, and more flexible. Three optical beam forming techniques are identified as applicable to large spaceborne phased array antennas. They are (1) the optical fiber replacement of conventional RF phased array distribution and control components, (2) spatial beam forming, and (3) optical beam splitting with integrated quasi-optical components. The optical fiber replacement and the spatial beam forming approaches were pursued by many organizations. Two new optical beam forming architectures are presented. Both architectures involve monolithic integration of the antenna radiating elements with quasi-optical grid detector arrays. The advantages of the grid detector array in the optical process are the higher power handling capability and the dynamic range. One architecture involves a modified version of the original spatial beam forming approach. The basic difference is the spatial light modulator (SLM) device for controlling the aperture field distribution. The original liquid crystal light valve SLM is replaced by an optical shuffling SLM, which was demonstrated for the 'smart pixel' technology. The advantages are the capability of generating the agile beams of a phased array antenna and to provide simultaneous transmit and receive functions. The second architecture considered is the optical beam splitting approach. This architecture involves an alternative amplitude control for each antenna element with an optical beam power divider comprised of mirrors and beam splitters. It also implements the quasi-optical grid phase shifter for phase control and grid amplifier for RF power. The advantages are no SLM is required for this approach, and the complete antenna system is capable of full monolithic integration.

Multi-time scale control of demand flexibility in smart distribution networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattarai, Bishnu; Myers, Kurt; Bak-Jensen, Birgitte

This study presents a multi-timescale control strategy to deploy demand flexibilities of electric vehicles (EV) for providing system balancing and local congestion management by simultaneously ensuring economic benefits to participating actors. First, the EV charging problem from consumer, aggregator, and grid operator’s perspective is investigated. A hierarchical control architecture (HCA) comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating a multi-time scale control, which works from a day-ahead scheduling up to real-time adaptive control. The performance of the developed method is investigated with high EV penetration in a typical distributionmore » network. The simulation results demonstrates that HCA exploit EV flexibility to solve grid unbalancing and congestions with simultaneous maximization of economic benefits by ensuring EV participation to day-ahead, balancing, and regulation markets. For the given network configuration and pricing structure, HCA ensures the EV owners to get paid up to 5 times the cost they were paying without control.« less

Multi-time scale control of demand flexibility in smart distribution networks

DOE PAGES

Bhattarai, Bishnu; Myers, Kurt; Bak-Jensen, Birgitte; ...

2017-01-01

This study presents a multi-timescale control strategy to deploy demand flexibilities of electric vehicles (EV) for providing system balancing and local congestion management by simultaneously ensuring economic benefits to participating actors. First, the EV charging problem from consumer, aggregator, and grid operator’s perspective is investigated. A hierarchical control architecture (HCA) comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating a multi-time scale control, which works from a day-ahead scheduling up to real-time adaptive control. The performance of the developed method is investigated with high EV penetration in a typical distributionmore » network. The simulation results demonstrates that HCA exploit EV flexibility to solve grid unbalancing and congestions with simultaneous maximization of economic benefits by ensuring EV participation to day-ahead, balancing, and regulation markets. For the given network configuration and pricing structure, HCA ensures the EV owners to get paid up to 5 times the cost they were paying without control.« less

HappyFace as a generic monitoring tool for HEP experiments

NASA Astrophysics Data System (ADS)

Kawamura, Gen; Magradze, Erekle; Musheghyan, Haykuhi; Quadt, Arnulf; Rzehorz, Gerhard

2015-12-01

The importance of monitoring on HEP grid computing systems is growing due to a significant increase in their complexity. Computer scientists and administrators have been studying and building effective ways to gather information on and clarify a status of each local grid infrastructure. The HappyFace project aims at making the above-mentioned workflow possible. It aggregates, processes and stores the information and the status of different HEP monitoring resources into the common database of HappyFace. The system displays the information and the status through a single interface. However, this model of HappyFace relied on the monitoring resources which are always under development in the HEP experiments. Consequently, HappyFace needed to have direct access methods to the grid application and grid service layers in the different HEP grid systems. To cope with this issue, we use a reliable HEP software repository, the CernVM File System. We propose a new implementation and an architecture of HappyFace, the so-called grid-enabled HappyFace. It allows its basic framework to connect directly to the grid user applications and the grid collective services, without involving the monitoring resources in the HEP grid systems. This approach gives HappyFace several advantages: Portability, to provide an independent and generic monitoring system among the HEP grid systems. Eunctionality, to allow users to perform various diagnostic tools in the individual HEP grid systems and grid sites. Elexibility, to make HappyFace beneficial and open for the various distributed grid computing environments. Different grid-enabled modules, to connect to the Ganga job monitoring system and to check the performance of grid transfers among the grid sites, have been implemented. The new HappyFace system has been successfully integrated and now it displays the information and the status of both the monitoring resources and the direct access to the grid user applications and the grid collective services.

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

Distributed intrusion detection system based on grid security model

NASA Astrophysics Data System (ADS)

Su, Jie; Liu, Yahui

2008-03-01

Grid computing has developed rapidly with the development of network technology and it can solve the problem of large-scale complex computing by sharing large-scale computing resource. In grid environment, we can realize a distributed and load balance intrusion detection system. This paper first discusses the security mechanism in grid computing and the function of PKI/CA in the grid security system, then gives the application of grid computing character in the distributed intrusion detection system (IDS) based on Artificial Immune System. Finally, it gives a distributed intrusion detection system based on grid security system that can reduce the processing delay and assure the detection rates.

Leveraging GeoTIFF Compatibility for Visualizing a New EASE-Grid 2.0 Global Satellite Passive Microwave Climate Record

NASA Astrophysics Data System (ADS)

Paget, A. C.; Brodzik, M. J.; Long, D. G.; Hardman, M.

2016-02-01

The historical record of satellite-derived passive microwave brightness temperatures comprises data from multiple imaging radiometers (SMMR, SSM/I-SSMIS, AMSR-E), spanning nearly 40 years of Earth observations from 1978 to the present. Passive microwave data are used to monitor time series of many climatological variables, including ocean wind speeds, cloud liquid water and sea ice concentrations and ice velocity. Gridded versions of passive microwave data have been produced using various map projections (polar stereographic, Lambert azimuthal equal-area, cylindrical equal-area, quarter-degree Platte-Carree) and data formats (flat binary, HDF). However, none of the currently available versions can be rendered in the common visualization standard, geoTIFF, without requiring cartographic reprojection. Furthermore, the reprojection details are complicated and often require expert knowledge of obscure software package options. We are producing a consistently calibrated, completely reprocessed data set of this valuable multi-sensor satellite record, using EASE-Grid 2.0, an improved equal-area projection definition that will require no reprojection for translation into geoTIFF. Our approach has been twofold: 1) define the projection ellipsoid to match the reference datum of the satellite data, and 2) include required file-level metadata for standard projection software to correctly render the data in the geoTIFF standard. The Calibrated, Enhanced Resolution Brightness Temperature (CETB) Earth System Data Record (ESDR), leverages image reconstruction techniques to enhance gridded spatial resolution to 3 km and uses newly available intersensor calibrations to improve the quality of derived geophysical products. We expect that our attention to easy geoTIFF compatibility will foster higher-quality analysis with the CETB product by enabling easy and correct intercomparison with other gridded and in situ data.

Unstructured Cartesian/prismatic grid generation for complex geometries

NASA Technical Reports Server (NTRS)

Karman, Steve L., Jr.

1995-01-01

The generation of a hybrid grid system for discretizing complex three dimensional (3D) geometries is described. The primary grid system is an unstructured Cartesian grid automatically generated using recursive cell subdivision. This grid system is sufficient for computing Euler solutions about extremely complex 3D geometries. A secondary grid system, using triangular-prismatic elements, may be added for resolving the boundary layer region of viscous flows near surfaces of solid bodies. This paper describes the grid generation processes used to generate each grid type. Several example grids are shown, demonstrating the ability of the method to discretize complex geometries, with very little pre-processing required by the user.

Data Grid Management Systems

NASA Technical Reports Server (NTRS)

Moore, Reagan W.; Jagatheesan, Arun; Rajasekar, Arcot; Wan, Michael; Schroeder, Wayne

2004-01-01

The "Grid" is an emerging infrastructure for coordinating access across autonomous organizations to distributed, heterogeneous computation and data resources. Data grids are being built around the world as the next generation data handling systems for sharing, publishing, and preserving data residing on storage systems located in multiple administrative domains. A data grid provides logical namespaces for users, digital entities and storage resources to create persistent identifiers for controlling access, enabling discovery, and managing wide area latencies. This paper introduces data grids and describes data grid use cases. The relevance of data grids to digital libraries and persistent archives is demonstrated, and research issues in data grids and grid dataflow management systems are discussed.

Parallel-wire grid assembly with method and apparatus for construction thereof

DOEpatents

Lewandowski, E.F.; Vrabec, J.

1981-10-26

Disclosed is a parallel wire grid and an apparatus and method for making the same. The grid consists of a generally coplanar array of parallel spaced-apart wires secured between metallic frame members by an electrically conductive epoxy. The method consists of continuously winding a wire about a novel winding apparatus comprising a plurality of spaced-apart generally parallel spindles. Each spindle is threaded with a number of predeterminedly spaced-apart grooves which receive and accurately position the wire at predetermined positions along the spindle. Overlying frame members coated with electrically conductive epoxy are then placed on either side of the wire array and are drawn together. After the epoxy hardens, portions of the wire array lying outside the frame members are trimmed away.

Parallel-wire grid assembly with method and apparatus for construction thereof

DOEpatents

Lewandowski, Edward F.; Vrabec, John

1984-01-01

Disclosed is a parallel wire grid and an apparatus and method for making the same. The grid consists of a generally coplanar array of parallel spaced-apart wires secured between metallic frame members by an electrically conductive epoxy. The method consists of continuously winding a wire about a novel winding apparatus comprising a plurality of spaced-apart generally parallel spindles. Each spindle is threaded with a number of predeterminedly spaced-apart grooves which receive and accurately position the wire at predetermined positions along the spindle. Overlying frame members coated with electrically conductive epoxy are then placed on either side of the wire array and are drawn together. After the epoxy hardens, portions of the wire array lying outside the frame members are trimmed away.

Parabolic dish systems at work - Applying the concepts

NASA Technical Reports Server (NTRS)

Marriott, A. T.

1981-01-01

An overview is given of parabolic dish solar concentrator application experiments being conducted by the U.S. Department of Energy. The 'engineering experiments' comprise the testing of (1) a small-community powerplant system, in conjunction with a grid-connected utility; (2) stand-alone applications at remote sites such as military installations, radar stations and villages; and (3) dish modules that can deliver heat for direct use in industrial processes. Applicability projections are based on a dish and receiver that use a Brayton engine with an engine/generator efficiency of 25% and a production level of up to 25,000 units per year. Analyses indicate that parabolic-dish power systems can potentially replace small, oil-fired power plants in all regions of the U.S. between 1985 and 1991.

Electro-optic crystal mosaics for the generation of terahertz radiation

DOEpatents

Carrig, Timothy J.; Taylor, Antoinette J.; Stewart, Kevin R.

1996-01-01

Apparatus for the generation of high energy terahertz radiation is presented and comprises laser means effective to produce subpicosecond optical pulses and a mosaic comprising a plurality of planar electro-optic crystals fastened together edge to edge in the form of a grid. The electro-optic crystals are in optical communication with the subpicosecond optical pulses, and behave as a single large electro-optic crystal, producing high energy terahertz radiation by way of optical rectification.

Electro-optic crystal mosaics for the generation of terahertz radiation

DOEpatents

Carrig, T.J.; Taylor, A.J.; Stewart, K.R.

1996-08-06

Apparatus for the generation of high energy terahertz radiation is presented and comprises laser means effective to produce subpicosecond optical pulses and a mosaic comprising a plurality of planar electro-optic crystals fastened together edge to edge in the form of a grid. The electro-optic crystals are in optical communication with the subpicosecond optical pulses, and behave as a single large electro-optic crystal, producing high energy terahertz radiation by way of optical rectification. 5 figs.

Exploiting opportunistic resources for ATLAS with ARC CE and the Event Service

NASA Astrophysics Data System (ADS)

Cameron, D.; Filipčič, A.; Guan, W.; Tsulaia, V.; Walker, R.; Wenaus, T.; ATLAS Collaboration

2017-10-01

With ever-greater computing needs and fixed budgets, big scientific experiments are turning to opportunistic resources as a means to add much-needed extra computing power. These resources can be very different in design from those that comprise the Grid computing of most experiments, therefore exploiting them requires a change in strategy for the experiment. They may be highly restrictive in what can be run or in connections to the outside world, or tolerate opportunistic usage only on condition that tasks may be terminated without warning. The Advanced Resource Connector Computing Element (ARC CE) with its nonintrusive architecture is designed to integrate resources such as High Performance Computing (HPC) systems into a computing Grid. The ATLAS experiment developed the ATLAS Event Service (AES) primarily to address the issue of jobs that can be terminated at any point when opportunistic computing capacity is needed by someone else. This paper describes the integration of these two systems in order to exploit opportunistic resources for ATLAS in a restrictive environment. In addition to the technical details, results from deployment of this solution in the SuperMUC HPC centre in Munich are shown.

Switching Logic for Converting Off-grid PV Customers to On-grid by Utilizing Off-grid Inverter and Battery

NASA Astrophysics Data System (ADS)

Anishkumar, A. R.; Sreejaya, P.

2016-12-01

Kerala is a state in India having a very good potential for solar PV energy production. The domestic customers in Kerala using PV system are approximately 15 % and almost all of them are using the off-grid PV system. When these off grid customers move to on-grid system, off grid system accessories such as inverter and batteries become redundant. In this paper, a switching logic has been developed for the effective utilization of off grid accessories and reducing islanding power loss for on grid customers. An algorithm is proposed for the switching logic and it is verified using simulation results and hardware implementation.

Mechanics of Granular Materials (MGM) Test Cell

NASA Technical Reports Server (NTRS)

2004-01-01

Test cells comprise specimen sand contained in a latex membrane (with a grid pattern for CCD cameras) between metal end plates and housed in a water-filled Lexan jacket. Experiment flown on STS-79 and STS-89. Principal Investigator: Dr. Stein Sture.

The National Grid Project: A system overview

NASA Technical Reports Server (NTRS)

Gaither, Adam; Gaither, Kelly; Jean, Brian; Remotigue, Michael; Whitmire, John; Soni, Bharat; Thompson, Joe; Dannenhoffer,, John; Weatherill, Nigel

1995-01-01

The National Grid Project (NGP) is a comprehensive numerical grid generation software system that is being developed at the National Science Foundation (NSF) Engineering Research Center (ERC) for Computational Field Simulation (CFS) at Mississippi State University (MSU). NGP is supported by a coalition of U.S. industries and federal laboratories. The objective of the NGP is to significantly decrease the amount of time it takes to generate a numerical grid for complex geometries and to increase the quality of these grids to enable computational field simulations for applications in industry. A geometric configuration can be discretized into grids (or meshes) that have two fundamental forms: structured and unstructured. Structured grids are formed by intersecting curvilinear coordinate lines and are composed of quadrilateral (2D) and hexahedral (3D) logically rectangular cells. The connectivity of a structured grid provides for trivial identification of neighboring points by incrementing coordinate indices. Unstructured grids are composed of cells of any shape (commonly triangles, quadrilaterals, tetrahedra and hexahedra), but do not have trivial identification of neighbors by incrementing an index. For unstructured grids, a set of points and an associated connectivity table is generated to define unstructured cell shapes and neighboring points. Hybrid grids are a combination of structured grids and unstructured grids. Chimera (overset) grids are intersecting or overlapping structured grids. The NGP system currently provides a user interface that integrates both 2D and 3D structured and unstructured grid generation, a solid modeling topology data management system, an internal Computer Aided Design (CAD) system based on Non-Uniform Rational B-Splines (NURBS), a journaling language, and a grid/solution visualization system.

Integrated geometry and grid generation system for complex configurations

NASA Technical Reports Server (NTRS)

Akdag, Vedat; Wulf, Armin

1992-01-01

A grid generation system was developed that enables grid generation for complex configurations. The system called ICEM/CFD is described and its role in computational fluid dynamics (CFD) applications is presented. The capabilities of the system include full computer aided design (CAD), grid generation on the actual CAD geometry definition using robust surface projection algorithms, interfacing easily with known CAD packages through common file formats for geometry transfer, grid quality evaluation of the volume grid, coupling boundary condition set-up for block faces with grid topology generation, multi-block grid generation with or without point continuity and block to block interface requirement, and generating grid files directly compatible with known flow solvers. The interactive and integrated approach to the problem of computational grid generation not only substantially reduces manpower time but also increases the flexibility of later grid modifications and enhancements which is required in an environment where CFD is integrated into a product design cycle.

NaradaBrokering as Middleware Fabric for Grid-based Remote Visualization Services

NASA Astrophysics Data System (ADS)

Pallickara, S.; Erlebacher, G.; Yuen, D.; Fox, G.; Pierce, M.

2003-12-01

Remote Visualization Services (RVS) have tended to rely on approaches based on the client server paradigm. The simplicity in these approaches is offset by problems such as single-point-of-failures, scaling and availability. Furthermore, as the complexity, scale and scope of the services hosted on this paradigm increase, this approach becomes increasingly unsuitable. We propose a scheme based on top of a distributed brokering infrastructure, NaradaBrokering, which comprises a distributed network of broker nodes. These broker nodes are organized in a cluster-based architecture that can scale to very large sizes. The broker network is resilient to broker failures and efficiently routes interactions to entities that expressed an interest in them. In our approach to RVS, services advertise their capabilities to the broker network, which manages these service advertisements. Among the services considered within our system are those that perform graphic transformations, mediate access to specialized datasets and finally those that manage the execution of specified tasks. There could be multiple instances of each of these services and the system ensures that load for a given service is distributed efficiently over these service instances. Among the features provided in our approach are efficient discovery of services and asynchronous interactions between services and service requestors (which could themselves be other services). Entities need not be online during the execution of the service request. The system also ensures that entities can be notified about task executions, partial results and failures that might have taken place during service execution. The system also facilitates specification of task overrides, distribution of execution results to alternate devices (which were not used to originally request service execution) and to multiple users. These RVS services could of course be either OGSA (Open Grid Services Architecture) based Grid services or traditional Web services. The brokering infrastructure will manage the service advertisements and the invocation of these services. This scheme ensures that the fundamental Grid computing concept is met - provide computing capabilities of those that are willing to provide it to those that seek the same. {[1]} The NaradaBrokering Project: http://www.naradabrokering.org

Occupancy change detection system and method

DOEpatents

Bruemmer, David J [Idaho Falls, ID; Few, Douglas A [Idaho Falls, ID

2009-09-01

A robot platform includes perceptors, locomotors, and a system controller. The system controller executes instructions for producing an occupancy grid map of an environment around the robot, scanning the environment to generate a current obstacle map relative to a current robot position, and converting the current obstacle map to a current occupancy grid map. The instructions also include processing each grid cell in the occupancy grid map. Within the processing of each grid cell, the instructions include comparing each grid cell in the occupancy grid map to a corresponding grid cell in the current occupancy grid map. For grid cells with a difference, the instructions include defining a change vector for each changed grid cell, wherein the change vector includes a direction from the robot to the changed grid cell and a range from the robot to the changed grid cell.

Establishment of key grid-connected performance index system for integrated PV-ES system

NASA Astrophysics Data System (ADS)

Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

2016-08-01

In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

Johnson Space Center's Solar and Wind-Based Renewable Energy System

NASA Technical Reports Server (NTRS)

Vasquez, A.; Ewert, M.; Rowlands, J.; Post, K.

2009-01-01

The NASA Johnson Space Center (JSC) in Houston, Texas has a Sustainability Partnership team that seeks ways for earth-based sustainability practices to also benefit space exploration research. A renewable energy gathering system was installed in 2007 at the JSC Child Care Center (CCC) which also offers a potential test bed for space exploration power generation and remote monitoring and control concepts. The system comprises: 1) several different types of photovoltaic panels (29 kW), 2) two wind-turbines (3.6 kW total), and 3) one roof-mounted solar thermal water heater and tank. A tie to the JSC local electrical grid was provided to accommodate excess power. The total first year electrical energy production was 53 megawatt-hours. A web-based real-time metering system collects and reports system performance and weather data. Improvements in areas of the CCC that were detected during subsequent energy analyses and some concepts for future efforts are also presented.

Grid-connected photovoltaic (PV) systems with batteries storage as solution to electrical grid outages in Burkina Faso

NASA Astrophysics Data System (ADS)

Abdoulaye, D.; Koalaga, Z.; Zougmore, F.

2012-02-01

This paper deals with a key solution for power outages problem experienced by many African countries and this through grid-connected photovoltaic (PV) systems with batteries storage. African grids are characterized by an insufficient power supply and frequent interruptions. Due to this fact, users who especially use classical grid-connected photovoltaic systems are unable to profit from their installation even if there is sun. In this study, we suggest the using of a grid-connected photovoltaic system with batteries storage as a solution to these problems. This photovoltaic system works by injecting the surplus of electricity production into grid and can also deliver electricity as a stand-alone system with all security needed. To achieve our study objectives, firstly we conducted a survey of a real situation of one African electrical grid, the case of Burkina Faso (SONABEL: National Electricity Company of Burkina). Secondly, as study case, we undertake a sizing, a modeling and a simulation of a grid-connected PV system with batteries storage for the LAME laboratory at the University of Ouagadougou. The simulation shows that the proposed grid-connected system allows users to profit from their photovoltaic installation at any time even if the public electrical grid has some failures either during the day or at night.

Grid Integration Studies: Advancing Clean Energy Planning and Deployment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katz, Jessica; Chernyakhovskiy, Ilya

2016-07-01

Integrating significant variable renewable energy (VRE) into the grid requires an evolution in power system planning and operation. To plan for this evolution, power system stakeholders can undertake grid integration studies. This Greening the Grid document reviews grid integration studies, common elements, questions, and guidance for system planners.

Numerical computation of complex multi-body Navier-Stokes flows with applications for the integrated Space Shuttle launch vehicle

NASA Technical Reports Server (NTRS)

Chan, William M.

1993-01-01

An enhanced grid system for the Space Shuttle Orbiter was built by integrating CAD definitions from several sources and then generating the surface and volume grids. The new grid system contains geometric components not modeled previously plus significant enhancements on geometry that has been modeled in the old grid system. The new orbiter grids were then integrated with new grids for the rest of the launch vehicle. Enhancements were made to the hyperbolic grid generator HYPGEN and new tools for grid projection, manipulation, and modification, Cartesian box grid and far field grid generation and post-processing of flow solver data were developed.

Design and Performance of a 1 mm3 Resolution Clinical PET System Comprising 3-D Position Sensitive Scintillation Detectors.

PubMed

Hsu, David F C; Freese, David L; Reynolds, Paul D; Innes, Derek R; Levin, Craig S

2018-04-01

We are developing a 1-mm 3 resolution, high-sensitivity positron emission tomography (PET) system for loco-regional cancer imaging. The completed system will comprise two cm detector panels and contain 4 608 position sensitive avalanche photodiodes (PSAPDs) coupled to arrays of mm 3 LYSO crystal elements for a total of 294 912 crystal elements. For the first time, this paper summarizes the design and reports the performance of a significant portion of the final clinical PET system, comprising 1 536 PSAPDs, 98 304 crystal elements, and an active field-of-view (FOV) of cm. The sub-system performance parameters, such as energy, time, and spatial resolutions are predictive of the performance of the final system due to the modular design. Analysis of the multiplexed crystal flood histograms shows 84% of the crystal elements have>99% crystal identification accuracy. The 511 keV photopeak energy resolution was 11.34±0.06% full-width half maximum (FWHM), and coincidence timing resolution was 13.92 ± 0.01 ns FWHM at 511 keV. The spatial resolution was measured using maximum likelihood expectation maximization reconstruction of a grid of point sources suspended in warm background. The averaged resolution over the central 6 cm of the FOV is 1.01 ± 0.13 mm in the X-direction, 1.84 ± 0.20 mm in the Y-direction, and 0.84 ± 0.11 mm in the Z-direction. Quantitative analysis of acquired micro-Derenzo phantom images shows better than 1.2 mm resolution at the center of the FOV, with subsequent resolution degradation in the y-direction toward the edge of the FOV caused by limited angle tomography effects.

Using Grid Benchmarks for Dynamic Scheduling of Grid Applications

NASA Technical Reports Server (NTRS)

Frumkin, Michael; Hood, Robert

2003-01-01

Navigation or dynamic scheduling of applications on computational grids can be improved through the use of an application-specific characterization of grid resources. Current grid information systems provide a description of the resources, but do not contain any application-specific information. We define a GridScape as dynamic state of the grid resources. We measure the dynamic performance of these resources using the grid benchmarks. Then we use the GridScape for automatic assignment of the tasks of a grid application to grid resources. The scalability of the system is achieved by limiting the navigation overhead to a few percent of the application resource requirements. Our task submission and assignment protocol guarantees that the navigation system does not cause grid congestion. On a synthetic data mining application we demonstrate that Gridscape-based task assignment reduces the application tunaround time.

Reliability analysis in interdependent smart grid systems

NASA Astrophysics Data System (ADS)

Peng, Hao; Kan, Zhe; Zhao, Dandan; Han, Jianmin; Lu, Jianfeng; Hu, Zhaolong

2018-06-01

Complex network theory is a useful way to study many real complex systems. In this paper, a reliability analysis model based on complex network theory is introduced in interdependent smart grid systems. In this paper, we focus on understanding the structure of smart grid systems and studying the underlying network model, their interactions, and relationships and how cascading failures occur in the interdependent smart grid systems. We propose a practical model for interdependent smart grid systems using complex theory. Besides, based on percolation theory, we also study the effect of cascading failures effect and reveal detailed mathematical analysis of failure propagation in such systems. We analyze the reliability of our proposed model caused by random attacks or failures by calculating the size of giant functioning components in interdependent smart grid systems. Our simulation results also show that there exists a threshold for the proportion of faulty nodes, beyond which the smart grid systems collapse. Also we determine the critical values for different system parameters. In this way, the reliability analysis model based on complex network theory can be effectively utilized for anti-attack and protection purposes in interdependent smart grid systems.

Grid Research | Grid Modernization | NREL

Science.gov Websites

Grid Research Grid Research NREL addresses the challenges of today's electric grid through high researcher in a lab Integrated Devices and Systems Developing and evaluating grid technologies and integrated Controls Developing methods for real-time operations and controls of power systems at any scale Photo of

Future evolution of distributed systems for smart grid - The challenges and opportunities to using decentralized energy system

NASA Astrophysics Data System (ADS)

Konopko, Joanna

2015-12-01

A decentralized energy system is a relatively new approach in the power industry. Decentralized energy systems provide promising opportunities for deploying renewable energy sources locally available as well as for expanding access to clean energy services to remote communities. The electricity system of the future must produce and distribute electricity that is reliable and affordable. To accomplish these goals, both the electricity grid and the existing regulatory system must be smarter. In this paper, the major issues and challenges in distributed systems for smart grid are discussed and future trends are presented. The smart grid technologies and distributed generation systems are explored. A general overview of the comparison of the traditional grid and smart grid is also included.

Grid systems for Earth radiation budget experiment applications

NASA Technical Reports Server (NTRS)

Brooks, D. R.

1981-01-01

Spatial coordinate transformations are developed for several global grid systems of interest to the Earth Radiation Budget Experiment. The grid boxes are defined in terms of a regional identifier and longitude-latitude indexes. The transformations associate longitude with a particular grid box. The reverse transformations identify the center location of a given grid box. Transformations are given to relate the rotating (Earth-based) grid systems to solar position expressed in an inertial (nonrotating) coordinate system. The FORTRAN implementations of the transformations are given, along with sample input and output.

7 CFR 1710.102 - Borrower eligibility for different types of loans.

Code of Federal Regulations, 2014 CFR

2014-01-01

... implementation of demand side management, energy conservation programs, and on grid and off grid renewable energy... management, energy conservation programs, and on grid and off grid renewable energy systems. (c) One hundred..., energy conservation programs, and on grid and off grid renewable energy systems. (See 7 CFR part 1712...

Research and design of smart grid monitoring control via terminal based on iOS system

NASA Astrophysics Data System (ADS)

Fu, Wei; Gong, Li; Chen, Heli; Pan, Guangji

2017-06-01

Aiming at a series of problems existing in current smart grid monitoring Control Terminal, such as high costs, poor portability, simple monitoring system, poor software extensions, low system reliability when transmitting information, single man-machine interface, poor security, etc., smart grid remote monitoring system based on the iOS system has been designed. The system interacts with smart grid server so that it can acquire grid data through WiFi/3G/4G networks, and monitor each grid line running status, as well as power plant equipment operating conditions. When it occurs an exception in the power plant, incident information can be sent to the user iOS terminal equipment timely, which will provide troubleshooting information to help the grid staff to make the right decisions in a timely manner, to avoid further accidents. Field tests have shown the system realizes the integrated grid monitoring functions, low maintenance cost, friendly interface, high security and reliability, and it possesses certain applicable value.

Spiking Neurons in a Hierarchical Self-Organizing Map Model Can Learn to Develop Spatial and Temporal Properties of Entorhinal Grid Cells and Hippocampal Place Cells

PubMed Central

Pilly, Praveen K.; Grossberg, Stephen

2013-01-01

Medial entorhinal grid cells and hippocampal place cells provide neural correlates of spatial representation in the brain. A place cell typically fires whenever an animal is present in one or more spatial regions, or places, of an environment. A grid cell typically fires in multiple spatial regions that form a regular hexagonal grid structure extending throughout the environment. Different grid and place cells prefer spatially offset regions, with their firing fields increasing in size along the dorsoventral axes of the medial entorhinal cortex and hippocampus. The spacing between neighboring fields for a grid cell also increases along the dorsoventral axis. This article presents a neural model whose spiking neurons operate in a hierarchy of self-organizing maps, each obeying the same laws. This spiking GridPlaceMap model simulates how grid cells and place cells may develop. It responds to realistic rat navigational trajectories by learning grid cells with hexagonal grid firing fields of multiple spatial scales and place cells with one or more firing fields that match neurophysiological data about these cells and their development in juvenile rats. The place cells represent much larger spaces than the grid cells, which enable them to support navigational behaviors. Both self-organizing maps amplify and learn to categorize the most frequent and energetic co-occurrences of their inputs. The current results build upon a previous rate-based model of grid and place cell learning, and thus illustrate a general method for converting rate-based adaptive neural models, without the loss of any of their analog properties, into models whose cells obey spiking dynamics. New properties of the spiking GridPlaceMap model include the appearance of theta band modulation. The spiking model also opens a path for implementation in brain-emulating nanochips comprised of networks of noisy spiking neurons with multiple-level adaptive weights for controlling autonomous adaptive robots capable of spatial navigation. PMID:23577130

TADS: A CFD-based turbomachinery and analysis design system with GUI. Volume 2: User's manual

NASA Technical Reports Server (NTRS)

Myers, R. A.; Topp, D. A.; Delaney, R. A.

1995-01-01

The primary objective of this study was the development of a computational fluid dynamics (CFD) based turbomachinery airfoil analysis and design system, controlled by a graphical user interface (GUI). The computer codes resulting from this effort are referred to as the Turbomachinery Analysis and Design System (TADS). This document is intended to serve as a user's manual for the computer programs which comprise the TADS system. TADS couples a throughflow solver (ADPAC) with a quasi-3D blade-to-blade solver (RVCQ3D) in an interactive package. Throughflow analysis capability was developed in ADPAC through the addition of blade force and blockage terms to the governing equations. A GUI was developed to simplify user input and automate the many tasks required to perform turbomachinery analysis and design. The coupling of various programs was done in a way that alternative solvers or grid generators could be easily incorporated into the TADS framework.

A Distribution Level Wide Area Monitoring System for the Electric Power Grid–FNET/GridEye

DOE PAGES

Liu, Yong; You, Shutang; Yao, Wenxuan; ...

2017-02-09

The wide area monitoring system (WAMS) is considered a pivotal component of future electric power grids. As a pilot WAMS that has been operated for more than a decade, the frequency monitoring network FNET/GridEye makes use of hundreds of global positioning system-synchronized phasor measurement sensors to capture the increasingly complicated grid behaviors across the interconnected power systems. In this paper, the FNET/GridEye system is overviewed and its operation experiences in electric power grid wide area monitoring are presented. Particularly, the implementation of a number of data analytics applications will be discussed in details. FNET/GridEye lays a firm foundation for themore » later WAMS operation in the electric power industry.« less

The on-line coupled atmospheric chemistry model system MECO(n) - Part 5: Expanding the Multi-Model-Driver (MMD v2.0) for 2-way data exchange including data interpolation via GRID (v1.0)

NASA Astrophysics Data System (ADS)

Kerkweg, Astrid; Hofmann, Christiane; Jöckel, Patrick; Mertens, Mariano; Pante, Gregor

2018-03-01

As part of the Modular Earth Submodel System (MESSy), the Multi-Model-Driver (MMD v1.0) was developed to couple online the regional Consortium for Small-scale Modeling (COSMO) model into a driving model, which can be either the regional COSMO model or the global European Centre Hamburg general circulation model (ECHAM) (see Part 2 of the model documentation). The coupled system is called MECO(n), i.e., MESSy-fied ECHAM and COSMO models nested n times. In this article, which is part of the model documentation of the MECO(n) system, the second generation of MMD is introduced. MMD comprises the message-passing infrastructure required for the parallel execution (multiple programme multiple data, MPMD) of different models and the communication of the individual model instances, i.e. between the driving and the driven models. Initially, the MMD library was developed for a one-way coupling between the global chemistry-climate ECHAM/MESSy atmospheric chemistry (EMAC) model and an arbitrary number of (optionally cascaded) instances of the regional chemistry-climate model COSMO/MESSy. Thus, MMD (v1.0) provided only functions for unidirectional data transfer, i.e. from the larger-scale to the smaller-scale models.Soon, extended applications requiring data transfer from the small-scale model back to the larger-scale model became of interest. For instance, the original fields of the larger-scale model can directly be compared to the upscaled small-scale fields to analyse the improvements gained through the small-scale calculations, after the results are upscaled. Moreover, the fields originating from the two different models might be fed into the same diagnostic tool, e.g. the online calculation of the radiative forcing calculated consistently with the same radiation scheme. Last but not least, enabling the two-way data transfer between two models is the first important step on the way to a fully dynamical and chemical two-way coupling of the various model instances.In MMD (v1.0), interpolation between the base model grids is performed via the COSMO preprocessing tool INT2LM, which was implemented into the MMD submodel for online interpolation, specifically for mapping onto the rotated COSMO grid. A more flexible algorithm is required for the backward mapping. Thus, MMD (v2.0) uses the new MESSy submodel GRID for the generalised definition of arbitrary grids and for the transformation of data between them.In this article, we explain the basics of the MMD expansion and the newly developed generic MESSy submodel GRID (v1.0) and show some examples of the abovementioned applications.

Drones in Automation - Secured Unmanned Aerial Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morales Rodriguez, Marissa E.; Rooke, Sterling; Fuhr, Peter L.

Factories, refineries, utilities (water/wastewater, electric) and related industrial sites are complex systems and structures with inspection and maintenance procedures required for optimal operation and regulatory compliance. As a specific example, consider just the bulk electric power system which is comprised of more than 200,000 miles of highvoltage transmission lines, thousands of generation plants and millions of digital controls. More than 1,800 entities own and operate portions of the grid system, with thousands more involved in the operation of distribution networks across North America. The interconnected and interdependent nature of the bulk power system requires a consistent and systematic application ofmore » risk mitigation across the entire grid system to be truly effective. Similar situations are found throughout automation where frequently an aging infrastructure is in place too. Consider, for example, the situation present in a refinery or chemical processing setting with the requirement for leak detection inspection of pipes, interconnects and systems stretching across the plant. The current practices and challenges relating just to this task - leak detection and repair (LDAR) – of detecting any fugitive emissions present and documenting all measurements thereby meeting air compliance regulations are typically “handled” by a small army of individuals with handheld or backpack-sized detectors who crawl through piping racks conducting measurements at each flange. Such work is performed in difficult conditions (temperature, humidity, physically challenging) with frequently a high level of employee turnover. Finaly, enter low cost sensors and mobile platforms – in other words unmanned aerial systems (UASs, or drones) with enhanced sensing capabilities.« less

Drones in Automation - Secured Unmanned Aerial Systems

DOE PAGES

Morales Rodriguez, Marissa E.; Rooke, Sterling; Fuhr, Peter L.; ...

2017-05-01

Factories, refineries, utilities (water/wastewater, electric) and related industrial sites are complex systems and structures with inspection and maintenance procedures required for optimal operation and regulatory compliance. As a specific example, consider just the bulk electric power system which is comprised of more than 200,000 miles of highvoltage transmission lines, thousands of generation plants and millions of digital controls. More than 1,800 entities own and operate portions of the grid system, with thousands more involved in the operation of distribution networks across North America. The interconnected and interdependent nature of the bulk power system requires a consistent and systematic application ofmore » risk mitigation across the entire grid system to be truly effective. Similar situations are found throughout automation where frequently an aging infrastructure is in place too. Consider, for example, the situation present in a refinery or chemical processing setting with the requirement for leak detection inspection of pipes, interconnects and systems stretching across the plant. The current practices and challenges relating just to this task - leak detection and repair (LDAR) – of detecting any fugitive emissions present and documenting all measurements thereby meeting air compliance regulations are typically “handled” by a small army of individuals with handheld or backpack-sized detectors who crawl through piping racks conducting measurements at each flange. Such work is performed in difficult conditions (temperature, humidity, physically challenging) with frequently a high level of employee turnover. Finaly, enter low cost sensors and mobile platforms – in other words unmanned aerial systems (UASs, or drones) with enhanced sensing capabilities.« less

FermiGrid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yocum, D.R.; Berman, E.; Canal, P.

2007-05-01

As one of the founding members of the Open Science Grid Consortium (OSG), Fermilab enables coherent access to its production resources through the Grid infrastructure system called FermiGrid. This system successfully provides for centrally managed grid services, opportunistic resource access, development of OSG Interfaces for Fermilab, and an interface to the Fermilab dCache system. FermiGrid supports virtual organizations (VOs) including high energy physics experiments (USCMS, MINOS, D0, CDF, ILC), astrophysics experiments (SDSS, Auger, DES), biology experiments (GADU, Nanohub) and educational activities.

Wave ensemble forecast system for tropical cyclones in the Australian region

NASA Astrophysics Data System (ADS)

Zieger, Stefan; Greenslade, Diana; Kepert, Jeffrey D.

2018-05-01

Forecasting of waves under extreme conditions such as tropical cyclones is vitally important for many offshore industries, but there remain many challenges. For Northwest Western Australia (NW WA), wave forecasts issued by the Australian Bureau of Meteorology have previously been limited to products from deterministic operational wave models forced by deterministic atmospheric models. The wave models are run over global (resolution 1/4∘) and regional (resolution 1/10∘) domains with forecast ranges of + 7 and + 3 day respectively. Because of this relatively coarse resolution (both in the wave models and in the forcing fields), the accuracy of these products is limited under tropical cyclone conditions. Given this limited accuracy, a new ensemble-based wave forecasting system for the NW WA region has been developed. To achieve this, a new dedicated 8-km resolution grid was nested in the global wave model. Over this grid, the wave model is forced with winds from a bias-corrected European Centre for Medium Range Weather Forecast atmospheric ensemble that comprises 51 ensemble members to take into account the uncertainties in location, intensity and structure of a tropical cyclone system. A unique technique is used to select restart files for each wave ensemble member. The system is designed to operate in real time during the cyclone season providing + 10-day forecasts. This paper will describe the wave forecast components of this system and present the verification metrics and skill for specific events.

Restorative effects of curcumin on sleep-deprivation induced memory impairments and structural changes of the hippocampus in a rat model.

PubMed

Noorafshan, Ali; Karimi, Fatemeh; Kamali, Ali-Mohammad; Karbalay-Doust, Saied; Nami, Mohammad

2017-11-15

The present study examined the consequences of rapid eye-movement sleep-deprivation (REM-SD) with or without curcumin treatment. The outcome measures comprised quantitative features in the three-dimensional reconstruction (3DR) CA1 and dentate gyrus in experimental and control animals using stereological procedures. Male rats were arbitrarily assigned to nine groups based on the intervention and treatment administered including: 1-cage control+distilled water, 2-cage control+curcumin (100mg/kg/day), 3-cage control+olive oil, 4-REM-SD+distilled water, 5-REM-SD+curcumin, 6-REM-SD+olive oil, 7-grid-floor control+distilled water, 8-grid-floor control+curcumin, and 9-grid-floor control+olive oil. Animals in the latter three groups were placed on wire-mesh grids in the sleep-deprivation box. REM-SD was induced by an apparatus comprising a water tank and multiple platforms. After a period of 21days, rats were submitted to the novel object-recognition task. Later, their brains were excised and evaluated using stereological methods. Our results indicated a respective 29% and 31% reduction in the total volume of CA1, and dentate gyrus in REM-SD+distilled water group as compared to the grid-floor control+distilled water group (p<0.05). Other than the above, the overall number of the pyramidal cells of CA1 and granular cells of dentate gyrus in the sleep-deprived group were found to be reduced by 48% and 25%, respectively. The REM-SD+distilled water group also exhibited impaired object recognition memory and deformed three-dimensional reconstructions of these regions. The volume, cell number, reconstruction, object recognition time, and body weight were however recovered in the REM-SD+curcumin compared to the REM-SD+distilled water group. This suggests the potential neuro-restorative effects of curcumin in our model. Copyright © 2017 Elsevier Inc. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Zhiwen; Eichman, Joshua D; Kurtz, Jennifer M

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 revenuemore » 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.« less

Monte Carlo design and simulation of a grid-type multi-layer pixel collimator for radiotherapy: Feasibility study

NASA Astrophysics Data System (ADS)

Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae Suk

2014-05-01

In order to confirm the possibility of field application of a different type collimator with a multileaf collimator (MLC), we constructed a grid-type multi-layer pixel collimator (GTPC) by using a Monte Carlo n-particle simulation (MCNPX). In this research, a number of factors related to the performance of the GPTC were evaluated using simulated output data of a basic MLC model. A layer was comprised of a 1024-pixel collimator (5.0 × 5.0 mm2) which could operate individually as a grid-type collimator (32 × 32). A 30-layer collimator was constructed for a specific portal form to pass radiation through the opening and closing of each pixel cover. The radiation attenuation level and the leakage were compared between the GTPC modality simulation and MLC modeling (tungsten, 17.50 g/cm3, 5.0 × 70.0 × 160.0 mm3) currently used for a radiation field. Comparisons of the portal imaging, the lateral dose profile from a virtual water phantom, the dependence of the performance on the increase in the number of layers, the radiation intensity modulation verification, and the geometric error between the GTPC and the MLC were done using the MCNPX simulation data. From the simulation data, the intensity modulation of the GTPC showed a faster response than the MLC's (29.6%). In addition, the agreement between the doses that should be delivered to the target region was measured as 97.0%, and the GTPC system had an error below 0.01%, which is identical to that of MLC. A Monte Carlo simulation of the GTPC could be useful for verification of application possibilities. Because the line artifact is caused by the grid frame and the folded cover, a lineal dose transfer type is chosen for the operation of this system. However, the result of GTPC's performance showed that the methods of effective intensity modulation and the specific geometric beam shaping differed with the MLC modality.

GRID3D-v2: An updated version of the GRID2D/3D computer program for generating grid systems in complex-shaped three-dimensional spatial domains

NASA Technical Reports Server (NTRS)

Steinthorsson, E.; Shih, T. I-P.; Roelke, R. J.

1991-01-01

In order to generate good quality systems for complicated three-dimensional spatial domains, the grid-generation method used must be able to exert rather precise controls over grid-point distributions. Several techniques are presented that enhance control of grid-point distribution for a class of algebraic grid-generation methods known as the two-, four-, and six-boundary methods. These techniques include variable stretching functions from bilinear interpolation, interpolating functions based on tension splines, and normalized K-factors. The techniques developed in this study were incorporated into a new version of GRID3D called GRID3D-v2. The usefulness of GRID3D-v2 was demonstrated by using it to generate a three-dimensional grid system in the coolent passage of a radial turbine blade with serpentine channels and pin fins.

Kwf-Grid workflow management system for Earth science applications

NASA Astrophysics Data System (ADS)

Tran, V.; Hluchy, L.

2009-04-01

In this paper, we present workflow management tool for Earth science applications in EGEE. The workflow management tool was originally developed within K-wf Grid project for GT4 middleware and has many advanced features like semi-automatic workflow composition, user-friendly GUI for managing workflows, knowledge management. In EGEE, we are porting the workflow management tool to gLite middleware for Earth science applications K-wf Grid workflow management system was developed within "Knowledge-based Workflow System for Grid Applications" under the 6th Framework Programme. The workflow mangement system intended to - semi-automatically compose a workflow of Grid services, - execute the composed workflow application in a Grid computing environment, - monitor the performance of the Grid infrastructure and the Grid applications, - analyze the resulting monitoring information, - capture the knowledge that is contained in the information by means of intelligent agents, - and finally to reuse the joined knowledge gathered from all participating users in a collaborative way in order to efficiently construct workflows for new Grid applications. Kwf Grid workflow engines can support different types of jobs (e.g. GRAM job, web services) in a workflow. New class of gLite job has been added to the system, allows system to manage and execute gLite jobs in EGEE infrastructure. The GUI has been adapted to the requirements of EGEE users, new credential management servlet is added to portal. Porting K-wf Grid workflow management system to gLite would allow EGEE users to use the system and benefit from its avanced features. The system is primarly tested and evaluated with applications from ES clusters.

Microwave limb sounder. [measuring trace gases in the upper atmosphere

NASA Technical Reports Server (NTRS)

Gustincic, J. J. (Inventor)

1981-01-01

Trace gases in the upper atmosphere can be measured by comparing spectral noise content of limb soundings with the spectral noise content of cold space. An offset Cassegrain antenna system and tiltable input mirror alternately look out at the limb and up at cold space at an elevation angle of about 22. The mirror can also be tilted to look at a black body calibration target. Reflection from the mirror is directed into a radiometer whose head functions as a diplexer to combine the input radiation and a local ocillator (klystron) beam. The radiometer head is comprised of a Fabry-Perot resonator consisting of two Fabry-Perot cavities spaced a number of half wavelengths apart. Incoming radiation received on one side is reflected and rotated 90 deg in polarization by the resonator so that it will be reflected by an input grid into a mixer, while the klystron beam received on the other side is also reflected and rotated 90 deg, but not without passing some energy to be reflected by the input grid into the mixer.

RETHINKING THE FUTURE GRID: INTEGRATED NUCLEAR-RENEWABLE ENERGY SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.M. Bragg-Sitton; R. Boardman

2014-12-01

The 2013 electricity generation mix in the United States consisted of ~13% renewables (hydropower, wind, solar, geothermal), 19% nuclear, 27% natural gas, and 39% coal. In the 2011 State of the Union Address, President Obama set a clean energy goal for the nation: “By 2035, 80 percent of America’s electricity will come from clean energy sources. Some folks want wind and solar. Others want nuclear, clean coal and natural gas. To meet this goal we will need them all.” The U.S. Department of Energy (DOE) Offices of Nuclear Energy (NE) and Energy Efficiency and Renewable Energy (EERE) recognize that “allmore » of the above” means that we are called to best utilize all available clean energy sources. To meet the stated environmental goals for electricity generation and for the broader energy sector, there is a need to transform the energy infrastructure of the U.S. and elsewhere. New energy systems must be capable of significantly reducing environmental impacts in an efficient and economically viable manner while utilizing both hydrocarbon resources and clean energy generation sources. The U.S. DOE is supporting research and development that could lead to more efficient utilization of clean energy generation sources, including renewable and nuclear options, to meet both grid demand and thermal energy needs in the industrial sector. A concept being advanced by the DOE-NE and DOE-EERE is tighter coupling of nuclear and renewable energy sources in a manner that better optimizes energy use for the combined electricity, industrial manufacturing, and the transportation sectors. This integration concept has been referred to as a “hybrid system” that is capable of apportioning thermal and electrical energy to first meet the grid demand (with appropriate power conversion systems), then utilizing excess thermal and, in some cases, electrical energy to drive a process that results in an additional product. For the purposes of the present work, the hybrid system would integrate two or more energy resources to generate two or more products, one of which must be an energy commodity, such as electricity or transportation fuel. Subsystems would be integrated ‘‘behind’’ the electrical transmission bus and would be comprised of two or more energy conversion subsystems that have traditionally been separate or isolated. Energy flows would be dynamically apportioned as necessary to meet grid demand via a single, highly responsive connection to the grid that provides dispatchable electricity while capital-intensive generation assets operate at full capacity. Candidate region-specific hybrid energy systems selected for further study and figures of merit that will be used to assess system performance will be presented.« less

Broad-band beam buncher

DOEpatents

Goldberg, D.A.; Flood, W.S.; Arthur, A.A.; Voelker, F.

1984-03-20

A broad-band beam bunther is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-

Technical and economic advantages of making lead-acid battery grids by continuous electroforming

NASA Astrophysics Data System (ADS)

Warlimont, H.; Hofmann, T.

A new continuous electroforming process to manufacture lead grids for automotive and industrial lead-acid batteries has been developed. A galvanic cell comprising a drum cathode for electroforming and a subsequent series of galvanic cells which form a strip galvanizing line are operating in a single, fully continuous, automatic process. Virgin lead or lead scrap may be used as the anode material. The product is grid strip of any specified thickness and design which can be fed into existing strip-pasting equipment. The composition and microstructure of the grid material can be varied to provide increased corrosion resistance and increased paste adherence. A unique feature of the material is its inherent layered composite structure that allows optimization of the properties according to particular functional requirements. Thus, both the specific power and the specific energy of the battery can be increased by reducing weight. The material properties increase the calendar life of the battery by increasing the corrosion resistance of the grid, and increase the cycle-life of the battery by improved adherence of the positive active material. The technical and economic features and competitive advantages of this new technology and product are presented in quantitative terms.

Sub-grid drag models for horizontal cylinder arrays immersed in gas-particle multiphase flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar, Avik; Sun, Xin; Sundaresan, Sankaran

2013-09-08

Immersed cylindrical tube arrays often are used as heat exchangers in gas-particle fluidized beds. In multiphase computational fluid dynamics (CFD) simulations of large fluidized beds, explicit resolution of small cylinders is computationally infeasible. Instead, the cylinder array may be viewed as an effective porous medium in coarse-grid simulations. The cylinders' influence on the suspension as a whole, manifested as an effective drag force, and on the relative motion between gas and particles, manifested as a correction to the gas-particle drag, must be modeled via suitable sub-grid constitutive relationships. In this work, highly resolved unit-cell simulations of flow around an arraymore » of horizontal cylinders, arranged in a staggered configuration, are filtered to construct sub-grid, or `filtered', drag models, which can be implemented in coarse-grid simulations. The force on the suspension exerted by the cylinders is comprised of, as expected, a buoyancy contribution, and a kinetic component analogous to fluid drag on a single cylinder. Furthermore, the introduction of tubes also is found to enhance segregation at the scale of the cylinder size, which, in turn, leads to a reduction in the filtered gas-particle drag.« less

Coupled atmosphere-biophysics-hydrology models for environmental modeling

USGS Publications Warehouse

Walko, R.L.; Band, L.E.; Baron, Jill S.; Kittel, T.G.F.; Lammers, R.; Lee, T.J.; Ojima, D.; Pielke, R.A.; Taylor, C.; Tague, C.; Tremback, C.J.; Vidale, P.L.

2000-01-01

The formulation and implementation of LEAF-2, the Land Ecosystem–Atmosphere Feedback model, which comprises the representation of land–surface processes in the Regional Atmospheric Modeling System (RAMS), is described. LEAF-2 is a prognostic model for the temperature and water content of soil, snow cover, vegetation, and canopy air, and includes turbulent and radiative exchanges between these components and with the atmosphere. Subdivision of a RAMS surface grid cell into multiple areas of distinct land-use types is allowed, with each subgrid area, or patch, containing its own LEAF-2 model, and each patch interacts with the overlying atmospheric column with a weight proportional to its fractional area in the grid cell. A description is also given of TOPMODEL, a land hydrology model that represents surface and subsurface downslope lateral transport of groundwater. Details of the incorporation of a modified form of TOPMODEL into LEAF-2 are presented. Sensitivity tests of the coupled system are presented that demonstrate the potential importance of the patch representation and of lateral water transport in idealized model simulations. Independent studies that have applied LEAF-2 and verified its performance against observational data are cited. Linkage of RAMS and TOPMODEL through LEAF-2 creates a modeling system that can be used to explore the coupled atmosphere–biophysical–hydrologic response to altered climate forcing at local watershed and regional basin scales.

GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

DOE PAGES

Chassin, David P.; Fuller, Jason C.; Djilali, Ned

2014-01-01

Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control systemmore » design, and integration of wind power in a smart grid.« less

GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chassin, David P.; Fuller, Jason C.; Djilali, Ned

2014-06-23

Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control systemmore » design, and integration of wind power in a smart grid.« less

Solar power plant performance evaluation: simulation and experimental validation

NASA Astrophysics Data System (ADS)

Natsheh, E. M.; Albarbar, A.

2012-05-01

In this work the performance of solar power plant is evaluated based on a developed model comprise photovoltaic array, battery storage, controller and converters. The model is implemented using MATLAB/SIMULINK software package. Perturb and observe (P&O) algorithm is used for maximizing the generated power based on maximum power point tracker (MPPT) implementation. The outcome of the developed model are validated and supported by a case study carried out using operational 28.8kW grid-connected solar power plant located in central Manchester. Measurements were taken over 21 month's period; using hourly average irradiance and cell temperature. It was found that system degradation could be clearly monitored by determining the residual (the difference) between the output power predicted by the model and the actual measured power parameters. It was found that the residual exceeded the healthy threshold, 1.7kW, due to heavy snow in Manchester last winter. More important, the developed performance evaluation technique could be adopted to detect any other reasons that may degrade the performance of the P V panels such as shading and dirt. Repeatability and reliability of the developed system performance were validated during this period. Good agreement was achieved between the theoretical simulation and the real time measurement taken the online grid connected solar power plant.

Automatic Overset Grid Generation with Heuristic Feedback Control

NASA Technical Reports Server (NTRS)

Robinson, Peter I.

2001-01-01

An advancing front grid generation system for structured Overset grids is presented which automatically modifies Overset structured surface grids and control lines until user-specified grid qualities are achieved. The system is demonstrated on two examples: the first refines a space shuttle fuselage control line until global truncation error is achieved; the second advances, from control lines, the space shuttle orbiter fuselage top and fuselage side surface grids until proper overlap is achieved. Surface grids are generated in minutes for complex geometries. The system is implemented as a heuristic feedback control (HFC) expert system which iteratively modifies the input specifications for Overset control line and surface grids. It is developed as an extension of modern control theory, production rules systems and subsumption architectures. The methodology provides benefits over the full knowledge lifecycle of an expert system for knowledge acquisition, knowledge representation, and knowledge execution. The vector/matrix framework of modern control theory systematically acquires and represents expert system knowledge. Missing matrix elements imply missing expert knowledge. The execution of the expert system knowledge is performed through symbolic execution of the matrix algebra equations of modern control theory. The dot product operation of matrix algebra is generalized for heuristic symbolic terms. Constant time execution is guaranteed.

Individual aerosol particles in ambient and updraft conditions below convective cloud bases in the Oman mountain region

NASA Astrophysics Data System (ADS)

Semeniuk, T. A.; Bruintjes, R. T.; Salazar, V.; Breed, D. W.; Jensen, T. L.; Buseck, P. R.

2014-03-01

An airborne study of cloud microphysics provided an opportunity to collect aerosol particles in ambient and updraft conditions of natural convection systems for transmission electron microscopy (TEM). Particles were collected simultaneously on lacey carbon and calcium-coated carbon (Ca-C) TEM grids, providing information on particle morphology and chemistry and a unique record of the particle's physical state on impact. In total, 22 particle categories were identified, including single, coated, aggregate, and droplet types. The fine fraction comprised up to 90% mixed cation sulfate (MCS) droplets, while the coarse fraction comprised up to 80% mineral-containing aggregates. Insoluble (dry), partially soluble (wet), and fully soluble particles (droplets) were recorded on Ca-C grids. Dry particles were typically silicate grains; wet particles were mineral aggregates with chloride, nitrate, or sulfate components; and droplets were mainly aqueous NaCl and MCS. Higher numbers of droplets were present in updrafts (80% relative humidity (RH)) compared with ambient conditions (60% RH), and almost all particles activated at cloud base (100% RH). Greatest changes in size and shape were observed in NaCl-containing aggregates (>0.3 µm diameter) along updraft trajectories. Their abundance was associated with high numbers of cloud condensation nuclei (CCN) and cloud droplets, as well as large droplet sizes in updrafts. Thus, compositional dependence was observed in activation behavior recorded for coarse and fine fractions. Soluble salts from local pollution and natural sources clearly affected aerosol-cloud interactions, enhancing the spectrum of particles forming CCN and by forming giant CCN from aggregates, thus, making cloud seeding with hygroscopic flares ineffective in this region.

Low-cost wireless voltage & current grid monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hines, Jacqueline

This report describes the development and demonstration of a novel low-cost wireless power distribution line monitoring system. This system measures voltage, current, and relative phase on power lines of up to 35 kV-class. The line units operate without any batteries, and without harvesting energy from the power line. Thus, data on grid condition is provided even in outage conditions, when line current is zero. This enhances worker safety by detecting the presence of voltage and current that may appear from stray sources on nominally isolated lines. Availability of low-cost power line monitoring systems will enable widespread monitoring of the distributionmore » grid. Real-time data on local grid operating conditions will enable grid operators to optimize grid operation, implement grid automation, and understand the impact of solar and other distributed sources on grid stability. The latter will enable utilities to implement eneygy storage and control systems to enable greater penetration of solar into the grid.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalimunthe, Amty Ma’rufah Ardhiyah; Mindara, Jajat Yuda; Panatarani, Camellia

Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for amore » renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become ‘smart’. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition.« less

Algebraic grid generation for coolant passages of turbine blades with serpentine channels and pin fins

NASA Technical Reports Server (NTRS)

Shih, T. I.-P.; Roelke, R. J.; Steinthorsson, E.

1991-01-01

In order to study numerically details of the flow and heat transfer within coolant passages of turbine blades, a method must first be developed to generate grid systems within the very complicated geometries involved. In this study, a grid generation package was developed that is capable of generating the required grid systems. The package developed is based on an algebraic grid generation technique that permits the user considerable control over how grid points are to be distributed in a very explicit way. These controls include orthogonality of grid lines next to boundary surfaces and ability to cluster about arbitrary points, lines, and surfaces. This paper describes that grid generation package and shows how it can be used to generate grid systems within complicated-shaped coolant passages via an example.

Woven-grid sealed quasi-bipolar lead-acid battery construction and fabricating method

NASA Technical Reports Server (NTRS)

Rippel, Wally E. (Inventor)

1989-01-01

A quasi-bipolar lead-acid battery construction includes a plurality of bipolar cells disposed in side-by-side relation to form a stack, and a pair of monoplanar plates at opposite ends of the stack, the cell stack and monopolar plates being contained within a housing of the battery. Each bipolar cell is loaded with an electrolyte and composed of a bipolar electrode plate and a pair of separator plates disposed on opposite sides of the electrode plate and peripherally sealed thereto. Each bipolar electrode plate is composed of a partition sheet and two bipolar electrode elements folded into a hairpin configuration and applied over opposite edges of the partition sheet so as to cover the opposite surfaces of the opposite halves thereof. Each bipolar electrode element is comprised of a woven grid with a hot-melt strip applied to a central longitudinal region of the grid along which the grid is folded into the hairpin configuration, and layers of negative and positive active material pastes applied to opposite halves of the grid on opposite sides of the central hot-melt strip. The grid is made up of strands of conductive and non-conductive yarns composing the respective transverse and longitudinal weaves of the grid. The conductive yarn has a multi-stranded glass core surrounded and covered by a lead sheath, whereas the non-conductive yarn has a multi-stranded glass core surrounded and covered by a thermally activated sizing.

Design of a photovoltaic system for a southwest all-electric residence

NASA Astrophysics Data System (ADS)

Mehalick, E. M.; Obrien, G.; Tully, G. F.; Johnson, J.; Parker, J.

1980-04-01

The grid connected residential photovoltaic system for the Southwest is designed to meet both space conditioning requirements and all conventional electrical load requirements for an all-electric residence. The system is comprised of two major subsystems, the solar array and the power conditioning subsystem (PCS). An 8 kW peak photovoltaic array been designed for the house. The 93 square meters solar array uses a shingle solar cell module in a highly redundant series/parallel matrix. The photovoltaic generated power is supplied to a 10kVA power conversion subsystem which is controlled to track the solar array maximum power operating point and feed the 240 Vac output power directly to the house loads or back to the utility when excess power is generated. The photovoltaic power is isolated from the utility by a 15 kVA transformer. The house design and subsystem specifications are given in detail.

A study of the diffusional behavior of a two-phase metal matrix composite exposed to a high temperature environment

NASA Technical Reports Server (NTRS)

Tenney, D. R.

1974-01-01

The progress of diffusion-controlled filament-matrix interaction in a metal matrix composite where the filaments and matrix comprise a two-phase binary alloy system was studied by mathematically modeling compositional changes resulting from prolonged elevated temperature exposure. The analysis treats a finite, diffusion-controlled, two-phase moving-interface problem by means of a variable-grid finite-difference technique. The Ni-W system was selected as an example system. Modeling was carried out for the 1000 to 1200 C temperature range for unidirectional composites containing from 6 to 40 volume percent tungsten filaments in a Ni matrix. The results are displayed to show both the change in filament diameter and matrix composition as a function of exposure time. Compositional profiles produced between first and second nearest neighbor filaments were calculated by superposition of finite-difference solutions of the diffusion equations.

Integrating Variable Renewable Energy into the Grid: Key Issues, Greening the Grid (Spanish Version)

DOE Office of Scientific and Technical Information (OSTI.GOV)

This is the Spanish version of 'Greening the Grid - Integrating Variable Renewable Energy into the Grid: Key Issues'. To foster sustainable, low-emission development, many countries are establishing ambitious renewable energy targets for their electricity supply. Because solar and wind tend to be more variable and uncertain than conventional sources, meeting these targets will involve changes to power system planning and operations. Grid integration is the practice of developing efficient ways to deliver variable renewable energy (VRE) to the grid. Good integration methods maximize the cost-effectiveness of incorporating VRE into the power system while maintaining or increasing system stability andmore » reliability. When considering grid integration, policy makers, regulators, and system operators consider a variety of issues, which can be organized into four broad topics: New Renewable Energy Generation, New Transmission, Increased System Flexibility, and Planning for a High RE Future.« less

TDIGG - TWO-DIMENSIONAL, INTERACTIVE GRID GENERATION CODE

NASA Technical Reports Server (NTRS)

Vu, B. T.

1994-01-01

TDIGG is a fast and versatile program for generating two-dimensional computational grids for use with finite-difference flow-solvers. Both algebraic and elliptic grid generation systems are included. The method for grid generation by algebraic transformation is based on an interpolation algorithm and the elliptic grid generation is established by solving the partial differential equation (PDE). Non-uniform grid distributions are carried out using a hyperbolic tangent stretching function. For algebraic grid systems, interpolations in one direction (univariate) and two directions (bivariate) are considered. These interpolations are associated with linear or cubic Lagrangian/Hermite/Bezier polynomial functions. The algebraic grids can subsequently be smoothed using an elliptic solver. For elliptic grid systems, the PDE can be in the form of Laplace (zero forcing function) or Poisson. The forcing functions in the Poisson equation come from the boundary or the entire domain of the initial algebraic grids. A graphics interface procedure using the Silicon Graphics (GL) Library is included to allow users to visualize the grid variations at each iteration. This will allow users to interactively modify the grid to match their applications. TDIGG is written in FORTRAN 77 for Silicon Graphics IRIS series computers running IRIX. This package requires either MIT's X Window System, Version 11 Revision 4 or SGI (Motif) Window System. A sample executable is provided on the distribution medium. It requires 148K of RAM for execution. The standard distribution medium is a .25 inch streaming magnetic IRIX tape cartridge in UNIX tar format. This program was developed in 1992.

Enhanced R200 with Frisch-Grid CZT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotnikov, A.

2017-12-01

The goal of this project is to demonstrate an engineering prototype of a gamma ray spectrometer that uses Cadmium Zinc Telluride (CZT) in a configuration comprised of an array of position-sensitive virtual Frisch grid (PSVFG) detectors and show its capability to perform functions that would be useful to the IAEA. The detectors should achieve energy resolution of ~2% at 200 keV and <1% at > 662 keV, thereby outperforming all hand-held instruments currently in use other than cryogenically cooled germanium. BNL will make every effort to transfer the technology to an industrial partner so that robust, fieldable instruments can bemore » manufactured.« less

Enhanced R200 with Frisch-Grid CZT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotnikov, Aleksey

The goal of this project is to demonstrate an engineering prototype of a gamma ray spectrometer that uses Cadmium Zinc Telluride (CZT) in a configuration comprised of an array of position-sensitive virtual Frisch grid (PSVFG) detectors and show its capability to perform functions that would be useful to the IAEA. The detectors should achieve energy resolution of ~2% at 200 keV and <1% at > 662 keV, thereby outperforming all hand-held instruments currently in use other than cryogenically cooled germanium. BNL will make every effort to transfer the technology to an industrial partner so that robust, fieldable instruments can bemore » manufactured.« less

In-situ spectrophotometric probe

DOEpatents

Prather, William S.

1992-01-01

A spectrophotometric probe for in situ absorption spectra measurements comprising a first optical fiber carrying light from a remote light source, a second optical fiber carrying light to a remote spectrophotometer, the proximal ends of the first and second optical fibers parallel and coterminal, a planoconvex lens to collimate light from the first optical fiber, a reflecting grid positioned a short distance from the lens to reflect the collimated light back to the lens for focussing on the second optical fiber. The lens is positioned with the convex side toward the optical fibers. A substrate for absorbing analyte or an analyte and reagent mixture may be positioned between the lens and the reflecting grid.

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

NASA Astrophysics Data System (ADS)

Shamsi, Pourya

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

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

NASA Astrophysics Data System (ADS)

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.

Dynamic Wireless Charging of Electric Vehicle Demonstrated at Oak Ridge National Laboratory: Benefit of Electrochemical Capacitor Smoothing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, John M; Onar, Omer C; White, Cliff P

2014-01-01

Abstract Wireless charging of an electric vehicle while in motion presents challenges in terms of low latency communications for roadway coil excitation sequencing, and maintenance of lateral alignment, plus the need for power flow smoothing. This paper summarizes the experimental results on power smoothing of in-motion wireless EV charging performed at Oak Ridge National Laboratory using various combinations of electrochemical capacitors at the grid-side and in-vehicle. Electrochemical capacitors of the symmetric carbon-carbon type from Maxwell Technologies comprised the in-vehicle smoothing of wireless charging current to the EV battery pack. Electro Standards Laboratories fabricated the passive and active parallel lithium-capacitor unitmore » used to smooth grid-side power. Power pulsation reduction was 81% on grid by LiC, and 84% on vehicle for both lithium-capacitor and the carbon ultracapacitors.« less

Method for fabricating solar cells having integrated collector grids

NASA Technical Reports Server (NTRS)

Evans, J. C., Jr. (Inventor)

1979-01-01

A heterojunction or Schottky barrier photovoltaic device comprising a conductive base metal layer compatible with and coating predominately the exposed surface of the p-type substrate of the device such that a back surface field region is formed at the interface between the device and the base metal layer, a transparent, conductive mixed metal oxide layer in integral contact with the n-type layer of the heterojunction or Schottky barrier device having a metal alloy grid network of the same metal elements of the oxide constituents of the mixed metal oxide layer embedded in the mixed metal oxide layer, an insulating layer which prevents electrical contact between the conductive metal base layer and the transparent, conductive metal oxide layer, and a metal contact means covering the insulating layer and in intimate contact with the metal grid network embedded in the transparent, conductive oxide layer for conducting electrons generated by the photovoltaic process from the device.

A Guidebook on Grid Interconnection and Islanded Operation of Mini-Grid Power Systems Up to 200 kW

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greacen, Chris; Engel, Richard; Quetchenbach, Thomas

A Guidebook on Grid Interconnection and Islanded Operation of Mini-Grid Power Systems Up to 200 kW is intended to help meet the widespread need for guidance, standards, and procedures for interconnecting mini-grids with the central electric grid as rural electrification advances in developing countries, bringing these once separate power systems together. The guidebook aims to help owners and operators of renewable energy mini-grids understand the technical options available, safety and reliability issues, and engineering and administrative costs of different choices for grid interconnection. The guidebook is intentionally brief but includes a number of appendices that point the reader to additionalmore » resources for indepth information. Not included in the scope of the guidebook are policy concerns about “who pays for what,” how tariffs should be set, or other financial issues that are also paramount when “the little grid connects to the big grid.”« less

Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

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) Program, which is the integration of diverse power devices in an optimal configuration for space and terrestrial applications.

Life cycle assessment and grid electricity: what do we know and what can we know?

PubMed

Weber, Christopher L; Jiaramillo, Paulina; Marriott, Joe; Samaras, Constantine

2010-03-15

The generation and distribution of electricity comprises nearly 40% of U.S. CO(2), emissions, as well as large shares of SO(2), NO(x), small particulates, and other toxins. Thus, correctly accounting for these electricity-related environmental releases is of great importance in life cycle assessment of products and processes. Unfortunately, there is no agreed-upon protocol for accounting for the environmental emissions associated with electricity, as well as significant uncertainty in the estimates. Here, we explore the limits of current knowledge about grid electricity in LCA and carbon footprinting for the U.S. electrical grid, and show that differences in standards, protocols, and reporting organizations can lead to important differences in estimates of CO(2) SO(2), and NO(x) emissions factors. We find a considerable divergence in published values for grid emissions factor in the U.S. We discuss the implications of this divergence and list recommendations for a standardized approach to accounting for air pollution emissions in life cycle assessment and policy analyses in a world with incomplete and uncertain information.

A Smart Home Test Bed for Undergraduate Education to Bridge the Curriculum Gap from Traditional Power Systems to Modernized Smart Grids

ERIC Educational Resources Information Center

Hu, Qinran; Li, Fangxing; Chen, Chien-fei

2015-01-01

There is a worldwide trend to modernize old power grid infrastructures to form future smart grids, which will achieve efficient, flexible energy consumption by using the latest technologies in communication, computing, and control. Smart grid initiatives are moving power systems curricula toward smart grids. Although the components of smart grids…

Interoperability of GADU in using heterogeneous Grid resources for bioinformatics applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sulakhe, D.; Rodriguez, A.; Wilde, M.

2008-03-01

Bioinformatics tools used for efficient and computationally intensive analysis of genetic sequences require large-scale computational resources to accommodate the growing data. Grid computational resources such as the Open Science Grid and TeraGrid have proved useful for scientific discovery. The genome analysis and database update system (GADU) is a high-throughput computational system developed to automate the steps involved in accessing the Grid resources for running bioinformatics applications. This paper describes the requirements for building an automated scalable system such as GADU that can run jobs on different Grids. The paper describes the resource-independent configuration of GADU using the Pegasus-based virtual datamore » system that makes high-throughput computational tools interoperable on heterogeneous Grid resources. The paper also highlights the features implemented to make GADU a gateway to computationally intensive bioinformatics applications on the Grid. The paper will not go into the details of problems involved or the lessons learned in using individual Grid resources as it has already been published in our paper on genome analysis research environment (GNARE) and will focus primarily on the architecture that makes GADU resource independent and interoperable across heterogeneous Grid resources.« less

Twelve Principles for Green Energy Storage in Grid Applications.

PubMed

Arbabzadeh, Maryam; Johnson, Jeremiah X; Keoleian, Gregory A; Rasmussen, Paul G; Thompson, Levi T

2016-01-19

The introduction of energy storage technologies to the grid could enable greater integration of renewables, improve system resilience and reliability, and offer cost effective alternatives to transmission and distribution upgrades. The integration of energy storage systems into the electrical grid can lead to different environmental outcomes based on the grid application, the existing generation mix, and the demand. Given this complexity, a framework is needed to systematically inform design and technology selection about the environmental impacts that emerge when considering energy storage options to improve sustainability performance of the grid. To achieve this, 12 fundamental principles specific to the design and grid application of energy storage systems are developed to inform policy makers, designers, and operators. The principles are grouped into three categories: (1) system integration for grid applications, (2) the maintenance and operation of energy storage, and (3) the design of energy storage systems. We illustrate the application of each principle through examples published in the academic literature, illustrative calculations, and a case study with an off-grid application of vanadium redox flow batteries (VRFBs). In addition, trade-offs that can emerge between principles are highlighted.

A Mesoscale Total Dissolved Solids Quantity and Quality Study Integrating Responses of Multiple Biological Components in Small Stream Communities

EPA Science Inventory

A 42-day dosing test with ions comprising an excess TDS was run using mesocosms colonized with natural stream water fed continuously. In gridded gravel beds biota from microbes through macroinvertebrates are measured and interact in a manner realistic of stream riffle/run ecology...

Models for the modern power grid

NASA Astrophysics Data System (ADS)

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.

CAGI: Computer Aided Grid Interface. A work in progress

NASA Technical Reports Server (NTRS)

Soni, Bharat K.; Yu, Tzu-Yi; Vaughn, David

1992-01-01

Progress realized in the development of a Computer Aided Grid Interface (CAGI) software system in integrating CAD/CAM geometric system output and/or Interactive Graphics Exchange Standard (IGES) files, geometry manipulations associated with grid generation, and robust grid generation methodologies is presented. CAGI is being developed in a modular fashion and will offer fast, efficient and economical response to geometry/grid preparation, allowing the ability to upgrade basic geometry in a step-by-step fashion interactively and under permanent visual control along with minimizing the differences between the actual hardware surface descriptions and corresponding numerical analog. The computer code GENIE is used as a basis. The Non-Uniform Rational B-Splines (NURBS) representation of sculptured surfaces is utilized for surface grid redistribution. The computer aided analysis system, PATRAN, is adapted as a CAD/CAM system. The progress realized in NURBS surface grid generation, the development of IGES transformer, and geometry adaption using PATRAN will be presented along with their applicability to grid generation associated with rocket propulsion applications.

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

NASA Astrophysics Data System (ADS)

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.

GridMan: A grid manipulation system

NASA Technical Reports Server (NTRS)

Eiseman, Peter R.; Wang, Zhu

1992-01-01

GridMan is an interactive grid manipulation system. It operates on grids to produce new grids which conform to user demands. The input grids are not constrained to come from any particular source. They may be generated by algebraic methods, elliptic methods, hyperbolic methods, parabolic methods, or some combination of methods. The methods are included in the various available structured grid generation codes. These codes perform the basic assembly function for the various elements of the initial grid. For block structured grids, the assembly can be quite complex due to a large number of clock corners, edges, and faces for which various connections and orientations must be properly identified. The grid generation codes are distinguished among themselves by their balance between interactive and automatic actions and by their modest variations in control. The basic form of GridMan provides a much more substantial level of grid control and will take its input from any of the structured grid generation codes. The communication link to the outside codes is a data file which contains the grid or section of grid.

Multi-off-grid methods in multi-step integration of ordinary differential equations

NASA Technical Reports Server (NTRS)

Beaudet, P. R.

1974-01-01

Description of methods of solving first- and second-order systems of differential equations in which all derivatives are evaluated at off-grid locations in order to circumvent the Dahlquist stability limitation on the order of on-grid methods. The proposed multi-off-grid methods require off-grid state predictors for the evaluation of the n derivatives at each step. Progressing forward in time, the off-grid states are predicted using a linear combination of back on-grid state values and off-grid derivative evaluations. A comparison is made between the proposed multi-off-grid methods and the corresponding Adams and Cowell on-grid integration techniques in integrating systems of ordinary differential equations, showing a significant reduction in the error at larger step sizes in the case of the multi-off-grid integrator.

Model of interaction in Smart Grid on the basis of multi-agent system

NASA Astrophysics Data System (ADS)

Engel, E. A.; Kovalev, I. V.; Engel, N. E.

2016-11-01

This paper presents model of interaction in Smart Grid on the basis of multi-agent system. The use of travelling waves in the multi-agent system describes the behavior of the Smart Grid from the local point, which is being the complement of the conventional approach. The simulation results show that the absorption of the wave in the distributed multi-agent systems is effectively simulated the interaction in Smart Grid.

Performance test of a grid-tied PV system to power a split air conditioner system in Surabaya

NASA Astrophysics Data System (ADS)

Tarigan, E.

2017-11-01

Air conditioner for cooling air is one of the major needs for those who live in hot climate area such as Indonesia. This work presents the performance test of a grid-tied PV system to power air conditioner under a hot tropical climate in Surabaya, Indonesia. A 800 WP grid-tied photovoltaic (PV) system was used, and its performance was tested to power a 0.5 pk of split air conditioner system. It was found that about 3.5 kWh daily energy was consumed by the tested air conditioner system, and about 80% it could be supplied from the PV system. While the other 20% was supplied by the grid during periods of low solar irradiation, 440 Wh of energy was fed into the grid during operation out of office hours. By using the grid-tied PV system, the energy production by PV system did not need to match the consumption of the air conditioner. However, a larger capacity of PV system would mean that a higher percentage of the load would be covered by PV system.

Greening the Grid - Advancing Solar, Wind, and Smart Grid Technologies (Spanish Version)

DOE Office of Scientific and Technical Information (OSTI.GOV)

This is the Spanish version of 'Greening the Grid - Advancing Solar, Wind, and Smart Grid Technologies'. Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid.

On automating domain connectivity for overset grids

NASA Technical Reports Server (NTRS)

Chiu, Ing-Tsau

1994-01-01

An alternative method for domain connectivity among systems of overset grids is presented. Reference uniform Cartesian systems of points are used to achieve highly efficient domain connectivity, and form the basis for a future fully automated system. The Cartesian systems are used to approximated body surfaces and to map the computational space of component grids. By exploiting the characteristics of Cartesian Systems, Chimera type hole-cutting and identification of donor elements for intergrid boundary points can be carried out very efficiently. The method is tested for a range of geometrically complex multiple-body overset grid systems.

Co-Simulation Platform For Characterizing Cyber Attacks in Cyber Physical Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadi, Mohammad A. H.; Ali, Mohammad Hassan; Dasgupta, Dipankar

Smart grid is a complex cyber physical system containing a numerous and variety of sources, devices, controllers and loads. Communication/Information infrastructure is the backbone of the smart grid system where different grid components are connected with each other through this structure. Therefore, the drawbacks of the information technology related issues are also becoming a part of the smart grid. Further, smart grid is also vulnerable to the grid related disturbances. For such a dynamic system, disturbance and intrusion detection is a paramount issue. This paper presents a Simulink and OPNET based co-simulated test bed to carry out a cyber-intrusion inmore » a cyber-network for modern power systems and smart grid. The effect of the cyber intrusion on the physical power system is also presented. The IEEE 30 bus power system model is used to demonstrate the effectiveness of the simulated testbed. The experiments were performed by disturbing the circuit breakers reclosing time through a cyber-attack in the cyber network. Different disturbance situations in the proposed test system are considered and the results indicate the effectiveness of the proposed co-simulated scheme.« less

STAMMEX high resolution gridded daily precipitation dataset over Germany: a new potential for regional precipitation climate research

NASA Astrophysics Data System (ADS)

Zolina, Olga; Simmer, Clemens; Kapala, Alice; Mächel, Hermann; Gulev, Sergey; Groisman, Pavel

2014-05-01

We present new high resolution precipitation daily grids developed at Meteorological Institute, University of Bonn and German Weather Service (DWD) under the STAMMEX project (Spatial and Temporal Scales and Mechanisms of Extreme Precipitation Events over Central Europe). Daily precipitation grids have been developed from the daily-observing precipitation network of DWD, which runs one of the World's densest rain gauge networks comprising more than 7500 stations. Several quality-controlled daily gridded products with homogenized sampling were developed covering the periods 1931-onwards (with 0.5 degree resolution), 1951-onwards (0.25 degree and 0.5 degree), and 1971-2000 (0.1 degree). Different methods were tested to select the best gridding methodology that minimizes errors of integral grid estimates over hilly terrain. Besides daily precipitation values with uncertainty estimates (which include standard estimates of the kriging uncertainty as well as error estimates derived by a bootstrapping algorithm), the STAMMEX data sets include a variety of statistics that characterize temporal and spatial dynamics of the precipitation distribution (quantiles, extremes, wet/dry spells, etc.). Comparisons with existing continental-scale daily precipitation grids (e.g., CRU, ECA E-OBS, GCOS) which include considerably less observations compared to those used in STAMMEX, demonstrate the added value of high-resolution grids for extreme rainfall analyses. These data exhibit spatial variability pattern and trends in precipitation extremes, which are missed or incorrectly reproduced over Central Europe from coarser resolution grids based on sparser networks. The STAMMEX dataset can be used for high-quality climate diagnostics of precipitation variability, as a reference for reanalyses and remotely-sensed precipitation products (including the upcoming Global Precipitation Mission products), and for input into regional climate and operational weather forecast models. We will present numerous application of the STAMMEX grids spanning from case studies of the major Central European floods to long-term changes in different precipitation statistics, including those accounting for the alternation of dry and wet periods and precipitation intensities associated with prolonged rainy episodes.

Updated population metadata for United States historical climatology network stations

USGS Publications Warehouse

Owen, T.W.; Gallo, K.P.

2000-01-01

The United States Historical Climatology Network (HCN) serial temperature dataset is comprised of 1221 high-quality, long-term climate observing stations. The HCN dataset is available in several versions, one of which includes population-based temperature modifications to adjust urban temperatures for the "heat-island" effect. Unfortunately, the decennial population metadata file is not complete as missing values are present for 17.6% of the 12 210 population values associated with the 1221 individual stations during the 1900-90 interval. Retrospective grid-based populations. Within a fixed distance of an HCN station, were estimated through the use of a gridded population density dataset and historically available U.S. Census county data. The grid-based populations for the HCN stations provide values derived from a consistent methodology compared to the current HCN populations that can vary as definitions of the area associated with a city change over time. The use of grid-based populations may minimally be appropriate to augment populations for HCN climate stations that lack any population data, and are recommended when consistent and complete population data are required. The recommended urban temperature adjustments based on the HCN and grid-based methods of estimating station population can be significantly different for individual stations within the HCN dataset.

Unstructured grid modelling of offshore wind farm impacts on seasonally stratified shelf seas

NASA Astrophysics Data System (ADS)

Cazenave, Pierre William; Torres, Ricardo; Allen, J. Icarus

2016-06-01

Shelf seas comprise approximately 7% of the world's oceans and host enormous economic activity. Development of energy installations (e.g. Offshore Wind Farms (OWFs), tidal turbines) in response to increased demand for renewable energy requires a careful analysis of potential impacts. Recent remote sensing observations have identified kilometre-scale impacts from OWFs. Existing modelling evaluating monopile impacts has fallen into two camps: small-scale models with individually resolved turbines looking at local effects; and large-scale analyses but with sub-grid scale turbine parameterisations. This work straddles both scales through a 3D unstructured grid model (FVCOM): wind turbine monopiles in the eastern Irish Sea are explicitly described in the grid whilst the overall grid domain covers the south-western UK shelf. Localised regions of decreased velocity extend up to 250 times the monopile diameter away from the monopile. Shelf-wide, the amplitude of the M2 tidal constituent increases by up to 7%. The turbines enhance localised vertical mixing which decreases seasonal stratification. The spatial extent of this extends well beyond the turbines into the surrounding seas. With significant expansion of OWFs on continental shelves, this work highlights the importance of how OWFs may impact coastal (e.g. increased flooding risk) and offshore (e.g. stratification and nutrient cycling) areas.

Error analysis for the proposed close grid geodynamic satellite measurement system (CLOGEOS)

NASA Technical Reports Server (NTRS)

Mueller, I. I.; Vangelder, B. H. W.; Kumar, M.

1975-01-01

The close grid geodynamic measurement system experiment which envisages an active ranging satellite and a grid of retro-reflectors or transponders in the San Andreas fault area is a detailed simulated study for recovering the relative positions in the grid. The close grid geodynamic measurement system for determining the relative motion of two plates in the California region (if feasible) could be used in other areas of the world to delineate and complete the picture of crustal motions over the entire globe and serve as a geodetic survey system. In addition, with less stringent accuracy standards, the system would also find usage in allied geological and marine geodesy fields.

Integrating PV in Distributed Grids: Solutions and Technologies Workshop |

Science.gov Websites

Energy Systems Integration Facility | NREL Integrating PV in Distributed Grids: Solutions and Technologies Workshop Integrating PV in Distributed Grids: Solutions and Technologies Workshop In October 2015 (PV) onto the grid. The workshop was held at the Energy Systems Integration Facility. Presenters from

Rotational-translational fourier imaging system requiring only one grid pair

NASA Technical Reports Server (NTRS)

Campbell, Jonathan W. (Inventor)

2006-01-01

The sky contains many active sources that emit X-rays, gamma rays, and neutrons. Unfortunately hard X-rays, gamma rays, and neutrons cannot be imaged by conventional optics. This obstacle led to the development of Fourier imaging systems. In early approaches, multiple grid pairs were necessary in order to create rudimentary Fourier imaging systems. At least one set of grid pairs was required to provide multiple real components of a Fourier derived image, and another set was required to provide multiple imaginary components of the image. It has long been recognized that the expense associated with the physical production of the numerous grid pairs required for Fourier imaging was a drawback. Herein one grid pair (two grids), with accompanying rotation and translation, can be used if one grid has one more slit than the other grid, and if the detector is modified.

Adaptive Mesh Refinement in Curvilinear Body-Fitted Grid Systems

NASA Technical Reports Server (NTRS)

Steinthorsson, Erlendur; Modiano, David; Colella, Phillip

1995-01-01

To be truly compatible with structured grids, an AMR algorithm should employ a block structure for the refined grids to allow flow solvers to take advantage of the strengths of unstructured grid systems, such as efficient solution algorithms for implicit discretizations and multigrid schemes. One such algorithm, the AMR algorithm of Berger and Colella, has been applied to and adapted for use with body-fitted structured grid systems. Results are presented for a transonic flow over a NACA0012 airfoil (AGARD-03 test case) and a reflection of a shock over a double wedge.

Distinction of Concept and Discussion on Construction Idea of Smart Water Grid Project

NASA Astrophysics Data System (ADS)

Ye, Y.; Yizi, S., Sr.; Lili, L., Sr.; Sang, X.; Zhai, J.

2016-12-01

Smart water grid project includes construction of water physical grid consisting of various flow regulating infrastructures, construction of water information grid in line with the trend of intelligent technology and construction of water management grid featured by system & mechanism construction and systemization of regulation decision-making. It is the integrated platform and comprehensive carrier for water conservancy practices. Currently, there still is dispute over engineering construction idea of smart water grid which, however, represents the future development trend of water management and is increasingly emphasized. The paper, based on distinction of concept of water grid and water grid engineering, explains the concept of water grid intelligentization, actively probes into construction idea of Smart water grid project in our country and presents scientific problems to be solved as well as core technologies to be mastered for smart water grid construction.

Wide-area, real-time monitoring and visualization system

DOEpatents

Budhraja, Vikram S.; Dyer, James D.; Martinez Morales, Carlos A.

2013-03-19

A real-time performance monitoring system for monitoring an electric power grid. The electric power grid has a plurality of grid portions, each grid portion corresponding to one of a plurality of control areas. The real-time performance monitoring system includes a monitor computer for monitoring at least one of reliability metrics, generation metrics, transmission metrics, suppliers metrics, grid infrastructure security metrics, and markets metrics for the electric power grid. The data for metrics being monitored by the monitor computer are stored in a data base, and a visualization of the metrics is displayed on at least one display computer having a monitor. The at least one display computer in one said control area enables an operator to monitor the grid portion corresponding to a different said control area.

Wide-area, real-time monitoring and visualization system

DOEpatents

Budhraja, Vikram S [Los Angeles, CA; Dyer, James D [La Mirada, CA; Martinez Morales, Carlos A [Upland, CA

2011-11-15

A real-time performance monitoring system for monitoring an electric power grid. The electric power grid has a plurality of grid portions, each grid portion corresponding to one of a plurality of control areas. The real-time performance monitoring system includes a monitor computer for monitoring at least one of reliability metrics, generation metrics, transmission metrics, suppliers metrics, grid infrastructure security metrics, and markets metrics for the electric power grid. The data for metrics being monitored by the monitor computer are stored in a data base, and a visualization of the metrics is displayed on at least one display computer having a monitor. The at least one display computer in one said control area enables an operator to monitor the grid portion corresponding to a different said control area.

Real-time performance monitoring and management system

DOEpatents

Budhraja, Vikram S [Los Angeles, CA; Dyer, James D [La Mirada, CA; Martinez Morales, Carlos A [Upland, CA

2007-06-19

A real-time performance monitoring system for monitoring an electric power grid. The electric power grid has a plurality of grid portions, each grid portion corresponding to one of a plurality of control areas. The real-time performance monitoring system includes a monitor computer for monitoring at least one of reliability metrics, generation metrics, transmission metrics, suppliers metrics, grid infrastructure security metrics, and markets metrics for the electric power grid. The data for metrics being monitored by the monitor computer are stored in a data base, and a visualization of the metrics is displayed on at least one display computer having a monitor. The at least one display computer in one said control area enables an operator to monitor the grid portion corresponding to a different said control area.

Aerodynamic simulation on massively parallel systems

NASA Technical Reports Server (NTRS)

Haeuser, Jochem; Simon, Horst D.

1992-01-01

This paper briefly addresses the computational requirements for the analysis of complete configurations of aircraft and spacecraft currently under design to be used for advanced transportation in commercial applications as well as in space flight. The discussion clearly shows that massively parallel systems are the only alternative which is both cost effective and on the other hand can provide the necessary TeraFlops, needed to satisfy the narrow design margins of modern vehicles. It is assumed that the solution of the governing physical equations, i.e., the Navier-Stokes equations which may be complemented by chemistry and turbulence models, is done on multiblock grids. This technique is situated between the fully structured approach of classical boundary fitted grids and the fully unstructured tetrahedra grids. A fully structured grid best represents the flow physics, while the unstructured grid gives best geometrical flexibility. The multiblock grid employed is structured within a block, but completely unstructured on the block level. While a completely unstructured grid is not straightforward to parallelize, the above mentioned multiblock grid is inherently parallel, in particular for multiple instruction multiple datastream (MIMD) machines. In this paper guidelines are provided for setting up or modifying an existing sequential code so that a direct parallelization on a massively parallel system is possible. Results are presented for three parallel systems, namely the Intel hypercube, the Ncube hypercube, and the FPS 500 system. Some preliminary results for an 8K CM2 machine will also be mentioned. The code run is the two dimensional grid generation module of Grid, which is a general two dimensional and three dimensional grid generation code for complex geometries. A system of nonlinear Poisson equations is solved. This code is also a good testcase for complex fluid dynamics codes, since the same datastructures are used. All systems provided good speedups, but message passing MIMD systems seem to be best suited for large miltiblock applications.

The eGo grid model: An open-source and open-data based synthetic medium-voltage grid model for distribution power supply systems

NASA Astrophysics Data System (ADS)

Amme, J.; Pleßmann, G.; Bühler, J.; Hülk, L.; Kötter, E.; Schwaegerl, P.

2018-02-01

The increasing integration of renewable energy into the electricity supply system creates new challenges for distribution grids. The planning and operation of distribution systems requires appropriate grid models that consider the heterogeneity of existing grids. In this paper, we describe a novel method to generate synthetic medium-voltage (MV) grids, which we applied in our DIstribution Network GeneratOr (DINGO). DINGO is open-source software and uses freely available data. Medium-voltage grid topologies are synthesized based on location and electricity demand in defined demand areas. For this purpose, we use GIS data containing demand areas with high-resolution spatial data on physical properties, land use, energy, and demography. The grid topology is treated as a capacitated vehicle routing problem (CVRP) combined with a local search metaheuristics. We also consider the current planning principles for MV distribution networks, paying special attention to line congestion and voltage limit violations. In the modelling process, we included power flow calculations for validation. The resulting grid model datasets contain 3608 synthetic MV grids in high resolution, covering all of Germany and taking local characteristics into account. We compared the modelled networks with real network data. In terms of number of transformers and total cable length, we conclude that the method presented in this paper generates realistic grids that could be used to implement a cost-optimised electrical energy system.

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

NASA Astrophysics Data System (ADS)

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Timothy M.; Palmintier, Bryan; Suryanarayanan, Siddharth

As more Smart Grid technologies (e.g., distributed photovoltaic, spatially distributed electric vehicle charging) are integrated into distribution grids, static distribution simulations are no longer sufficient for performing modeling and analysis. GridLAB-D is an agent-based distribution system simulation environment that allows fine-grained end-user models, including geospatial and network topology detail. A problem exists in that, without outside intervention, once the GridLAB-D simulation begins execution, it will run to completion without allowing the real-time interaction of Smart Grid controls, such as home energy management systems and aggregator control. We address this lack of runtime interaction by designing a flexible communication interface, Bus.pymore » (pronounced bus-dot-pie), that uses Python to pass messages between one or more GridLAB-D instances and a Smart Grid simulator. This work describes the design and implementation of Bus.py, discusses its usefulness in terms of some Smart Grid scenarios, and provides an example of an aggregator-based residential demand response system interacting with GridLAB-D through Bus.py. The small scale example demonstrates the validity of the interface and shows that an aggregator using said interface is able to control residential loads in GridLAB-D during runtime to cause a reduction in the peak load on the distribution system in (a) peak reduction and (b) time-of-use pricing cases.« less

Adapting a commercial power system simulator for smart grid based system study and vulnerability assessment

NASA Astrophysics Data System (ADS)

Navaratne, Uditha Sudheera

The smart grid is the future of the power grid. Smart meters and the associated network play a major role in the distributed system of the smart grid. Advance Metering Infrastructure (AMI) can enhance the reliability of the grid, generate efficient energy management opportunities and many innovations around the future smart grid. These innovations involve intense research not only on the AMI network itself but as also on the influence an AMI network can have upon the rest of the power grid. This research describes a smart meter testbed with hardware in loop that can facilitate future research in an AMI network. The smart meters in the testbed were developed such that their functionality can be customized to simulate any given scenario such as integrating new hardware components into a smart meter or developing new encryption algorithms in firmware. These smart meters were integrated into the power system simulator to simulate the power flow variation in the power grid on different AMI activities. Each smart meter in the network also provides a communication interface to the home area network. This research delivers a testbed for emulating the AMI activities and monitoring their effect on the smart grid.

Design of Energy Storage Management System Based on FPGA in Micro-Grid

NASA Astrophysics Data System (ADS)

Liang, Yafeng; Wang, Yanping; Han, Dexiao

2018-01-01

Energy storage system is the core to maintain the stable operation of smart micro-grid. Aiming at the existing problems of the energy storage management system in the micro-grid such as Low fault tolerance, easy to cause fluctuations in micro-grid, a new intelligent battery management system based on field programmable gate array is proposed : taking advantage of FPGA to combine the battery management system with the intelligent micro-grid control strategy. Finally, aiming at the problem that during estimation of battery charge State by neural network, initialization of weights and thresholds are not accurate leading to large errors in prediction results, the genetic algorithm is proposed to optimize the neural network method, and the experimental simulation is carried out. The experimental results show that the algorithm has high precision and provides guarantee for the stable operation of micro-grid.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadi, Mohammad A. H.; Dasgupta, Dipankar; Ali, Mohammad Hassan

The important backbone of the smart grid is the cyber/information infrastructure, which is primarily used to communicate with different grid components. A smart grid is a complex cyber physical system containing a numerous and variety number of sources, devices, controllers and loads. Therefore, the smart grid is vulnerable to grid related disturbances. For such dynamic system, disturbance and intrusion detection is a paramount issue. This paper presents a Simulink and Opnet based co-simulated platform to carry out a cyber-intrusion in cyber network for modern power systems and the smart grid. The IEEE 30 bus power system model is used tomore » demonstrate the effectiveness of the simulated testbed. The experiments were performed by disturbing the circuit breakers reclosing time through a cyber-attack. Different disturbance situations in the considered test system are considered and the results indicate the effectiveness of the proposed co-simulated scheme.« less

An Efficient Means of Adaptive Refinement Within Systems of Overset Grids

NASA Technical Reports Server (NTRS)

Meakin, Robert L.

1996-01-01

An efficient means of adaptive refinement within systems of overset grids is presented. Problem domains are segregated into near-body and off-body fields. Near-body fields are discretized via overlapping body-fitted grids that extend only a short distance from body surfaces. Off-body fields are discretized via systems of overlapping uniform Cartesian grids of varying levels of refinement. a novel off-body grid generation and management scheme provides the mechanism for carrying out adaptive refinement of off-body flow dynamics and solid body motion. The scheme allows for very efficient use of memory resources, and flow solvers and domain connectivity routines that can exploit the structure inherent to uniform Cartesian grids.

Free-air fumigation of mature trees. A novel system for controlled ozone enrichment in grown-up beech and spruce canopies.

PubMed

Werner, Herbert; Fabian, Peter

2002-01-01

A novel system for continuous and controlled free-air fumigation of mature tree canopies with ozone is described. Ozone generated from oxygen is diluted with air in a pressurized tank and conducted into the canopies by a system of 100 PTFE tubes hanging down from a grid fixed above the crowns. With 45 calibrated outlets per tube providing a constant flow of 0.3 l/min each, a total volume of about 10*10*15 m3 comprising 5 beech and 5 spruce canopies is fumigated. The spatial ozone distribution in the fumigated volume as well as surrounding reference tree canopies is controlled by continuous measuring instruments installed at 4 levels and a dense array of passive samplers. The system will later be used for CO2 fumigation as well. Results of the first year of continuous operation, with 2 * ambient ozone levels having been achieved, are reported.

Design of investment management optimization system for power grid companies under new electricity reform

NASA Astrophysics Data System (ADS)

Yang, Chunhui; Su, Zhixiong; Wang, Xin; Liu, Yang; Qi, Yongwei

2017-03-01

The new normalization of the economic situation and the implementation of a new round of electric power system reform put forward higher requirements to the daily operation of power grid companies. As an important day-to-day operation of power grid companies, investment management is directly related to the promotion of the company's operating efficiency and management level. In this context, the establishment of power grid company investment management optimization system will help to improve the level of investment management and control the company, which is of great significance for power gird companies to adapt to market environment changing as soon as possible and meet the policy environment requirements. Therefore, the purpose of this paper is to construct the investment management optimization system of power grid companies, which includes investment management system, investment process control system, investment structure optimization system, and investment project evaluation system and investment management information platform support system.

Impact of Considering 110 kV Grid Structures on the Congestion Management in the German Transmission Grid

NASA Astrophysics Data System (ADS)

Hoffrichter, André; Barrios, Hans; Massmann, Janek; Venkataramanachar, Bhavasagar; Schnettler, Armin

2018-02-01

The structural changes in the European energy system lead to an increase of renewable energy sources that are primarily connected to the distribution grid. Hence the stationary analysis of the transmission grid and the regionalization of generation capacities are strongly influenced by subordinate grid structures. To quantify the impact on the congestion management in the German transmission grid, a 110 kV grid model is derived using publicly available data delivered by Open Street Map and integrated into an existing model of the European transmission grid. Power flow and redispatch simulations are performed for three different regionalization methods and grid configurations. The results show a significant impact of the 110 kV system and prove an overestimation of power flows in the transmission grid when neglecting subordinate grids. Thus, the redispatch volume in Germany to dissolve bottlenecks in case of N-1 contingencies decreases by 38 % when considering the 110 kV grid.

NREL Partners With General Electric, Duke Energy on Grid Voltage Regulation

Science.gov Websites

Study | Energy Systems Integration Facility | NREL NREL Partners With General Electric, Duke Energy on Grid Voltage Regulation Study NREL Partners With General Electric, Duke Energy on Grid Voltage Regulation Study When a large solar photovoltaic (PV) system is connected to the electric grid, a utility's

Energy Management and Optimization Methods for Grid Energy Storage Systems

DOE PAGES

Byrne, Raymond H.; Nguyen, Tu A.; Copp, David A.; ...

2017-08-24

Today, the stability of the electric power grid is maintained through real time balancing of generation and demand. Grid scale energy storage systems are increasingly being deployed to provide grid operators the flexibility needed to maintain this balance. Energy storage also imparts resiliency and robustness to the grid infrastructure. Over the last few years, there has been a significant increase in the deployment of large scale energy storage systems. This growth has been driven by improvements in the cost and performance of energy storage technologies and the need to accommodate distributed generation, as well as incentives and government mandates. Energymore » management systems (EMSs) and optimization methods are required to effectively and safely utilize energy storage as a flexible grid asset that can provide multiple grid services. The EMS needs to be able to accommodate a variety of use cases and regulatory environments. In this paper, we provide a brief history of grid-scale energy storage, an overview of EMS architectures, and a summary of the leading applications for storage. These serve as a foundation for a discussion of EMS optimization methods and design.« less

Energy Management and Optimization Methods for Grid Energy Storage Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrne, Raymond H.; Nguyen, Tu A.; Copp, David A.

Today, the stability of the electric power grid is maintained through real time balancing of generation and demand. Grid scale energy storage systems are increasingly being deployed to provide grid operators the flexibility needed to maintain this balance. Energy storage also imparts resiliency and robustness to the grid infrastructure. Over the last few years, there has been a significant increase in the deployment of large scale energy storage systems. This growth has been driven by improvements in the cost and performance of energy storage technologies and the need to accommodate distributed generation, as well as incentives and government mandates. Energymore » management systems (EMSs) and optimization methods are required to effectively and safely utilize energy storage as a flexible grid asset that can provide multiple grid services. The EMS needs to be able to accommodate a variety of use cases and regulatory environments. In this paper, we provide a brief history of grid-scale energy storage, an overview of EMS architectures, and a summary of the leading applications for storage. These serve as a foundation for a discussion of EMS optimization methods and design.« less

Domain modeling and grid generation for multi-block structured grids with application to aerodynamic and hydrodynamic configurations

NASA Technical Reports Server (NTRS)

Spekreijse, S. P.; Boerstoel, J. W.; Vitagliano, P. L.; Kuyvenhoven, J. L.

1992-01-01

About five years ago, a joint development was started of a flow simulation system for engine-airframe integration studies on propeller as well as jet aircraft. The initial system was based on the Euler equations and made operational for industrial aerodynamic design work. The system consists of three major components: a domain modeller, for the graphical interactive subdivision of flow domains into an unstructured collection of blocks; a grid generator, for the graphical interactive computation of structured grids in blocks; and a flow solver, for the computation of flows on multi-block grids. The industrial partners of the collaboration and NLR have demonstrated that the domain modeller, grid generator and flow solver can be applied to simulate Euler flows around complete aircraft, including propulsion system simulation. Extension to Navier-Stokes flows is in progress. Delft Hydraulics has shown that both the domain modeller and grid generator can also be applied successfully for hydrodynamic configurations. An overview is given about the main aspects of both domain modelling and grid generation.

Design of Grid Portal System Based on RIA

NASA Astrophysics Data System (ADS)

Cao, Caifeng; Luo, Jianguo; Qiu, Zhixin

Grid portal is an important branch of grid research. In order to solve the weak expressive force, the poor interaction, the low operating efficiency and other insufficiencies of the first and second generation of grid portal system, RIA technology was introduced to it. A new portal architecture was designed based on RIA and Web service. The concrete realizing scheme of portal system was presented by using Adobe Flex/Flash technology, which formed a new design pattern. In system architecture, the design pattern has B/S and C/S superiorities, balances server and its client side, optimizes the system performance, realizes platform irrelevance. In system function, the design pattern realizes grid service call, provides client interface with rich user experience, integrates local resources by using FABridge, LCDS, Flash player and some other components.

Method of determining the x-ray limit of an ion gauge

DOEpatents

Edwards, Jr., David; Lanni, Christopher P.

1981-01-01

An ion gauge having a reduced "x-ray limit" and means for measuring that limit. The gauge comprises an ion gauge of the Bayard-Alpert type having a short collector and having means for varying the grid-collector voltage. The "x-ray limit" (i.e. the collector current resulting from x-rays striking the collector) may then be determined by the formula: ##EQU1## where: I.sub.x ="x-ray limit", I.sub.l and I.sub.h =the collector current at the lower and higher grid voltage respectively; and, .alpha.=the ratio of the collector current due to positive ions at the higher voltage to that at the lower voltage.

In-situ spectrophotometric probe

DOEpatents

Prather, W.S.

1992-12-15

A spectrophotometric probe is described for in situ absorption spectra measurements comprising a first optical fiber carrying light from a remote light source, a second optical fiber carrying light to a remote spectrophotometer, the proximal ends of the first and second optical fibers parallel and co-terminal, a planoconvex lens to collimate light from the first optical fiber, a reflecting grid positioned a short distance from the lens to reflect the collimated light back to the lens for focusing on the second optical fiber. The lens is positioned with the convex side toward the optical fibers. A substrate for absorbing analyte or an analyte and reagent mixture may be positioned between the lens and the reflecting grid. 5 figs.

Balancing Area Coordination: Efficiently Integrating Renewable Energy Into the Grid, Greening the Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katz, Jessica; Denholm, Paul; Cochran, Jaquelin

2015-06-01

Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. Coordinating balancing area operation can promote more cost and resource efficient integration of variable renewable energy, such as wind and solar, into power systems. This efficiency is achieved by sharing or coordinating balancing resources and operating reserves across larger geographic boundaries.

Ion accelerator systems for high power 30 cm thruster operation

NASA Technical Reports Server (NTRS)

Aston, G.

1982-01-01

Two and three-grid accelerator systems for high power ion thruster operation were investigated. Two-grid translation tests show that over compensation of the 30 cm thruster SHAG grid set spacing the 30 cm thruster radial plasma density variation and by incorporating grid compensation only sufficient to maintain grid hole axial alignment, it is shown that beam current gains as large as 50% can be realized. Three-grid translation tests performed with a simulated 30 cm thruster discharge chamber show that substantial beamlet steering can be reliably affected by decelerator grid translation only, at net-to-total voltage ratios as low as 0.05.

A chimera grid scheme. [multiple overset body-conforming mesh system for finite difference adaptation to complex aircraft configurations

NASA Technical Reports Server (NTRS)

Steger, J. L.; Dougherty, F. C.; Benek, J. A.

1983-01-01

A mesh system composed of multiple overset body-conforming grids is described for adapting finite-difference procedures to complex aircraft configurations. In this so-called 'chimera mesh,' a major grid is generated about a main component of the configuration and overset minor grids are used to resolve all other features. Methods for connecting overset multiple grids and modifications of flow-simulation algorithms are discussed. Computational tests in two dimensions indicate that the use of multiple overset grids can simplify the task of grid generation without an adverse effect on flow-field algorithms and computer code complexity.

Distributed Accounting on the Grid

NASA Technical Reports Server (NTRS)

Thigpen, William; Hacker, Thomas J.; McGinnis, Laura F.; Athey, Brian D.

2001-01-01

By the late 1990s, the Internet was adequately equipped to move vast amounts of data between HPC (High Performance Computing) systems, and efforts were initiated to link together the national infrastructure of high performance computational and data storage resources together into a general computational utility 'grid', analogous to the national electrical power grid infrastructure. The purpose of the Computational grid is to provide dependable, consistent, pervasive, and inexpensive access to computational resources for the computing community in the form of a computing utility. This paper presents a fully distributed view of Grid usage accounting and a methodology for allocating Grid computational resources for use on a Grid computing system.

The Hexapod Telescope -- A Never-ending Story

NASA Astrophysics Data System (ADS)

Chini, Rolf

The 1.5 m Hexapod Telescope is the prototype of a worldwide unique design concept for future telescopes. Its technical innovations comprise i) a mounting where the classical axes are replaced by six high-precision struts of variable lengths, ii) an actively controlled primary which consists of a thin Zerodur meniscus that is permanently fixed to a CFRP grid structure, iii) a secondary whose support legs are also designed as a Hexapod to compensate for gravitational deformation due to different elevations and, iv) a laser gyro system to provide the pointing. The telescope is currently tested in the Botanical Garden of the Ruhr-University Bochum and it is planned to transfer the instrument to Cerro Armazones, Chile after the world exhibition EXPO 2000.

A novel radiation detector for removing scattered radiation in chest radiography: Monte Carlo simulation-based performance evaluation

NASA Astrophysics Data System (ADS)

Roh, Y. H.; Yoon, Y.; Kim, K.; Kim, J.; Kim, J.; Morishita, J.

2016-10-01

Scattered radiation is the main reason for the degradation of image quality and the increased patient exposure dose in diagnostic radiology. In an effort to reduce scattered radiation, a novel structure of an indirect flat panel detector has been proposed. In this study, a performance evaluation of the novel system in terms of image contrast as well as an estimation of the number of photons incident on the detector and the grid exposure factor were conducted using Monte Carlo simulations. The image contrast of the proposed system was superior to that of the no-grid system but slightly inferior to that of the parallel-grid system. The number of photons incident on the detector and the grid exposure factor of the novel system were higher than those of the parallel-grid system but lower than those of the no-grid system. The proposed system exhibited the potential for reduced exposure dose without image quality degradation; additionally, can be further improved by a structural optimization considering the manufacturer's specifications of its lead contents.

Forest statistics for Arkansas' delta counties

Treesearch

Richard T. Quick; Mary S. Hedlund

1979-01-01

These tables were derived from data obtained during a 1978 inventory of 21 counties comprising the North and South Delta Units of Arkansas (fig. 1). Forest area was estimated from aerial photos with an adjustment for ground truth at selected locations. Sample plots were systematically established at three-mile intervals using a grid oriented roughly N-S and E-W. At...

Forest statistics for Arkansas' Ouachita counties

Treesearch

T. Richard Quick; Marry S. Hedlund

1979-01-01

These tables were derived from data obtained during a 1978 inventory of 10 counties comprising the Quachita Unit of Arkansas (fig. 1). Forest area was estimated from aerial photos with an adjustment of ground truth at selected locations. Sample plots were systematically established at three-mile intervals using a grid orientated roughly N-S and E-W. At each locations,...

Forest statistics for Arkansas' Ozark counties

Treesearch

T. Richard Quick; Mary S. Hedlund

1979-01-01

These tables were derived from data obtained during a 1978 inventory of 24 counties comprising the Ozark Unit of Arkansas (fib. 1). Forest area was estimated from aerial photos with an adjustment of ground truth at selected locations. Sample plots were systematically established at three-mile intervals using a grid orientated roughly N-S and E-W. At each location,...

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

NASA Astrophysics Data System (ADS)

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.

Market Evolution: Wholesale Electricity Market Design for 21st Century Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Jaquelin; Miller, Mackay; Milligan, Michael

2013-10-01

Demand for affordable, reliable, domestically sourced, and low-carbon electricity is on the rise. This growing demand is driven in part by evolving public policy priorities, especially reducing the health and environmental impacts of electricity service and expanding energy access to under-served customers. Consequently, variable renewable energy resources comprise an increasing share ofelectricity generation globally. At the same time, new opportunities for addressing the variability of renewables are being strengthened through advances in smart grids, communications, and technologies that enable dispatchable demand response and distributed generation to extend to the mass market. A key challenge of merging these opportunities is marketmore » design -- determining how to createincentives and compensate providers justly for attributes and performance that ensure a reliable and secure grid -- in a context that fully realizes the potential of a broad array of sources of flexibility in both the wholesale power and retail markets. This report reviews the suite of wholesale power market designs in use and under consideration to ensure adequacy, security, and flexibilityin a landscape of significant variable renewable energy. It also examines considerations needed to ensure that wholesale market designs are inclusive of emerging technologies, such as demand response, distributed generation, and storage.« less

Business Pattern of Distributed Energy in Electric Power System Reformation

NASA Astrophysics Data System (ADS)

Liang, YUE; Zhuochu, LIU; Jun, LI; Siwei, LI

2017-05-01

Under the trend of the electric power system revolution, the operation mode of micro power grid that including distributed power will be more diversified. User’s demand response and different strategies on electricity all have great influence on the operation of distributed power grid. This paper will not only research sensitive factors of micro power grid operation, but also analyze and calculate the cost and benefit of micro power grid operation upon different types. Then it will build a tech-economic calculation model, which applies to different types of micro power grid under the reformation of electric power system.

Software Surface Modeling and Grid Generation Steering Committee

NASA Technical Reports Server (NTRS)

Smith, Robert E. (Editor)

1992-01-01

It is a NASA objective to promote improvements in the capability and efficiency of computational fluid dynamics. Grid generation, the creation of a discrete representation of the solution domain, is an essential part of computational fluid dynamics. However, grid generation about complex boundaries requires sophisticated surface-model descriptions of the boundaries. The surface modeling and the associated computation of surface grids consume an extremely large percentage of the total time required for volume grid generation. Efficient and user friendly software systems for surface modeling and grid generation are critical for computational fluid dynamics to reach its potential. The papers presented here represent the state-of-the-art in software systems for surface modeling and grid generation. Several papers describe improved techniques for grid generation.

PNNL Future Power Grid Initiative-developed GridOPTICS Software System (GOSS)

ScienceCinema

None

2018-01-16

The power grid is changing and evolving. One aspect of this change is the growing use of smart meters and other devices, which are producing large volumes of useful data. However, in many cases, the data can’t be translated quickly into actionable guidance to improve grid performance. There's a need for innovative tools. The GridOPTICS(TM) Software System, or GOSS, developed through PNNL's Future Power Grid Initiative, is open source and became publicly available in spring 2014. The value of this middleware is that it easily integrates grid applications with sources of data and facilitates communication between them. Such a capability provides a foundation for developing a range of applications to improve grid management.

Increasing the resilience and security of the United States' power infrastructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Happenny, Sean F.

2015-08-01

The United States' power infrastructure is aging, underfunded, and vulnerable to cyber attack. Emerging smart grid technologies may take some of the burden off of existing systems and make the grid as a whole more efficient, reliable, and secure. The Pacific Northwest National Laboratory (PNNL) is funding research into several aspects of smart grid technology and grid security, creating a software simulation tool that will allow researchers to test power infrastructure control and distribution paradigms by utilizing different smart grid technologies to determine how the grid and these technologies react under different circumstances. Understanding how these systems behave in real-worldmore » conditions will lead to new ways to make our power infrastructure more resilient and secure. Demonstrating security in embedded systems is another research area PNNL is tackling. Many of the systems controlling the U.S. critical infrastructure, such as the power grid, lack integrated security and the aging networks protecting them are becoming easier to attack.« less

On the application of Chimera/unstructured hybrid grids for conjugate heat transfer

NASA Technical Reports Server (NTRS)

Kao, Kai-Hsiung; Liou, Meng-Sing

1995-01-01

A hybrid grid system that combines the Chimera overset grid scheme and an unstructured grid method is developed to study fluid flow and heat transfer problems. With the proposed method, the solid structural region, in which only the heat conduction is considered, can be easily represented using an unstructured grid method. As for the fluid flow region external to the solid material, the Chimera overset grid scheme has been shown to be very flexible and efficient in resolving complex configurations. The numerical analyses require the flow field solution and material thermal response to be obtained simultaneously. A continuous transfer of temperature and heat flux is specified at the interface, which connects the solid structure and the fluid flow as an integral system. Numerical results are compared with analytical and experimental data for a flat plate and a C3X cooled turbine cascade. A simplified drum-disk system is also simulated to show the effectiveness of this hybrid grid system.

AVQS: attack route-based vulnerability quantification scheme for smart grid.

PubMed

Ko, Jongbin; Lim, Hyunwoo; Lee, Seokjun; Shon, Taeshik

2014-01-01

A smart grid is a large, consolidated electrical grid system that includes heterogeneous networks and systems. Based on the data, a smart grid system has a potential security threat in its network connectivity. To solve this problem, we develop and apply a novel scheme to measure the vulnerability in a smart grid domain. Vulnerability quantification can be the first step in security analysis because it can help prioritize the security problems. However, existing vulnerability quantification schemes are not suitable for smart grid because they do not consider network vulnerabilities. We propose a novel attack route-based vulnerability quantification scheme using a network vulnerability score and an end-to-end security score, depending on the specific smart grid network environment to calculate the vulnerability score for a particular attack route. To evaluate the proposed approach, we derive several attack scenarios from the advanced metering infrastructure domain. The experimental results of the proposed approach and the existing common vulnerability scoring system clearly show that we need to consider network connectivity for more optimized vulnerability quantification.

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

NASA Technical Reports Server (NTRS)

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.

Grid Facilities | Grid Modernization | NREL

Science.gov Websites

groundbreaking innovations and collaboration in grid research. Photo of the Energy Systems Integration Facility Energy Systems Integration Facility The Energy Systems Integration Facility is the nation's premier user Located in Boulder, Colorado, the National Wind Technology Center (NWTC) offers similar integration

Development of a large scale Chimera grid system for the Space Shuttle Launch Vehicle

NASA Technical Reports Server (NTRS)

Pearce, Daniel G.; Stanley, Scott A.; Martin, Fred W., Jr.; Gomez, Ray J.; Le Beau, Gerald J.; Buning, Pieter G.; Chan, William M.; Chiu, Ing-Tsau; Wulf, Armin; Akdag, Vedat

1993-01-01

The application of CFD techniques to large problems has dictated the need for large team efforts. This paper offers an opportunity to examine the motivations, goals, needs, problems, as well as the methods, tools, and constraints that defined NASA's development of a 111 grid/16 million point grid system model for the Space Shuttle Launch Vehicle. The Chimera approach used for domain decomposition encouraged separation of the complex geometry into several major components each of which was modeled by an autonomous team. ICEM-CFD, a CAD based grid generation package, simplified the geometry and grid topology definition by provoding mature CAD tools and patch independent meshing. The resulting grid system has, on average, a four inch resolution along the surface.

Asteroseismology of KIC 7107778: a binary comprising almost identical subgiants

NASA Astrophysics Data System (ADS)

Li, Yaguang; Bedding, Timothy R.; Li, Tanda; Bi, Shaolan; Murphy, Simon J.; Corsaro, Enrico; Chen, Li; Tian, Zhijia

2018-05-01

We analyse an asteroseismic binary system: KIC 7107778, a non-eclipsing, unresolved target, with solar-like oscillations in both components. We used Kepler short cadence time series spanning nearly 2 yr to obtain the power spectrum. Oscillation mode parameters were determined using Bayesian inference and a nested sampling Monte Carlo algorithm with the DIAMONDS package. The power profiles of the two components fully overlap, indicating their close similarity. We modelled the two stars with MESA and calculated oscillation frequencies with GYRE. Stellar fundamental parameters (mass, radius, and age) were estimated by grid modelling with atmospheric parameters and the oscillation frequencies of l = 0, 2 modes as constraints. Most l = 1 mixed modes were identified with models searched using a bisection method. Stellar parameters for the two sub-giant stars are MA = 1.42 ± 0.06 M⊙, MB = 1.39 ± 0.03 M⊙, RA = 2.93 ± 0.05 R⊙, RB = 2.76 ± 0.04 R⊙, tA = 3.32 ± 0.54 Gyr and tB = 3.51 ± 0.33 Gyr. The mass difference of the system is ˜1 per cent. The results confirm their simultaneous birth and evolution, as is expected from binary formation. KIC 7107778 comprises almost identical twins, and is the first asteroseismic sub-giant binary to be detected.

Optimization of electrostatic dual-grid beam-deflection system

NASA Technical Reports Server (NTRS)

Hudson, W. R.; Lathem, W. C.; Power, J. L.; Banks, B. A.

1972-01-01

Tests were performed to minimize accelerator grid erosion of a 5-cm diameter Kaufman ion thruster due to direct beam impingement. Several different screen hole diameters, pillow-shape-square screen holes, and dished screen grids were tried. The optimization was accomplished by copper plating the accelerator grid before testing each grid configuration on a thruster for a 2-hour run. The thruster beam sputtered copper and molybdenum from the accelerator grid where the beam impinged. The observed erosion patterns and measured accelerator currents were used to determine how to modify the accelerator system. The lowest erosion was obtained for a 50-percent open area pillow-shape-square-aperture screen grid, dished 0.043 centimeter convex toward the accelerator grid, which was positioned with the center of the screen grid 0.084 centimeter from the accelerator grid. During this investigation the accelerator current was reduced from 120 to 55 microamperes and was also more uniformly distributed over the area of the accelerator grid.

Cloud Computing for the Grid: GridControl: A Software Platform to Support the Smart Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

GENI Project: Cornell University is creating a new software platform for grid operators called GridControl that will utilize cloud computing to more efficiently control the grid. In a cloud computing system, there are minimal hardware and software demands on users. The user can tap into a network of computers that is housed elsewhere (the cloud) and the network runs computer applications for the user. The user only needs interface software to access all of the cloud’s data resources, which can be as simple as a web browser. Cloud computing can reduce costs, facilitate innovation through sharing, empower users, and improvemore » the overall reliability of a dispersed system. Cornell’s GridControl will focus on 4 elements: delivering the state of the grid to users quickly and reliably; building networked, scalable grid-control software; tailoring services to emerging smart grid uses; and simulating smart grid behavior under various conditions.« less

System and method for islanding detection and prevention in distributed generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhowmik, Shibashis; Mazhari, Iman; Parkhideh, Babak

Various examples are directed to systems and methods for detecting an islanding condition at an inverter configured to couple a distributed generation system to an electrical grid network. A controller may determine a command frequency and a command frequency variation. The controller may determine that the command frequency variation indicates a potential islanding condition and send to the inverter an instruction to disconnect the distributed generation system from the electrical grid network. When the distributed generation system is disconnected from the electrical grid network, the controller may determine whether the grid network is valid.

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

NASA Astrophysics Data System (ADS)

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.

Evaluation of load flow and grid expansion in a unit-commitment and expansion optimization model SciGRID International Conference on Power Grid Modelling

NASA Astrophysics Data System (ADS)

Senkpiel, Charlotte; Biener, Wolfgang; Shammugam, Shivenes; Längle, Sven

2018-02-01

Energy system models serve as a basis for long term system planning. Joint optimization of electricity generating technologies, storage systems and the electricity grid leads to lower total system cost compared to an approach in which the grid expansion follows a given technology portfolio and their distribution. Modelers often face the problem of finding a good tradeoff between computational time and the level of detail that can be modeled. This paper analyses the differences between a transport model and a DC load flow model to evaluate the validity of using a simple but faster transport model within the system optimization model in terms of system reliability. The main findings in this paper are that a higher regional resolution of a system leads to better results compared to an approach in which regions are clustered as more overloads can be detected. An aggregation of lines between two model regions compared to a line sharp representation has little influence on grid expansion within a system optimizer. In a DC load flow model overloads can be detected in a line sharp case, which is therefore preferred. Overall the regions that need to reinforce the grid are identified within the system optimizer. Finally the paper recommends the usage of a load-flow model to test the validity of the model results.

Distributed data analysis in ATLAS

NASA Astrophysics Data System (ADS)

Nilsson, Paul; Atlas Collaboration

2012-12-01

Data analysis using grid resources is one of the fundamental challenges to be addressed before the start of LHC data taking. The ATLAS detector will produce petabytes of data per year, and roughly one thousand users will need to run physics analyses on this data. Appropriate user interfaces and helper applications have been made available to ensure that the grid resources can be used without requiring expertise in grid technology. These tools enlarge the number of grid users from a few production administrators to potentially all participating physicists. ATLAS makes use of three grid infrastructures for the distributed analysis: the EGEE sites, the Open Science Grid, and Nordu Grid. These grids are managed by the gLite workload management system, the PanDA workload management system, and ARC middleware; many sites can be accessed via both the gLite WMS and PanDA. Users can choose between two front-end tools to access the distributed resources. Ganga is a tool co-developed with LHCb to provide a common interface to the multitude of execution backends (local, batch, and grid). The PanDA workload management system provides a set of utilities called PanDA Client; with these tools users can easily submit Athena analysis jobs to the PanDA-managed resources. Distributed data is managed by Don Quixote 2, a system developed by ATLAS; DQ2 is used to replicate datasets according to the data distribution policies and maintains a central catalog of file locations. The operation of the grid resources is continually monitored by the Ganga Robot functional testing system, and infrequent site stress tests are performed using the Hammer Cloud system. In addition, the DAST shift team is a group of power users who take shifts to provide distributed analysis user support; this team has effectively relieved the burden of support from the developers.

Radiation-hardened fast acquisition/weak signal tracking system and method

NASA Technical Reports Server (NTRS)

Winternitz, Luke (Inventor); Boegner, Gregory J. (Inventor); Sirotzky, Steve (Inventor)

2009-01-01

A global positioning system (GPS) receiver and method of acquiring and tracking GPS signals comprises an antenna adapted to receive GPS signals; an analog radio frequency device operatively connected to the antenna and adapted to convert the GPS signals from an analog format to a digital format; a plurality of GPS signal tracking correlators operatively connected to the analog RF device; a GPS signal acquisition component operatively connected to the analog RF device and the plurality of GPS signal tracking correlators, wherein the GPS signal acquisition component is adapted to calculate a maximum vector on a databit correlation grid; and a microprocessor operatively connected to the plurality of GPS signal tracking correlators and the GPS signal acquisition component, wherein the microprocessor is adapted to compare the maximum vector with a predetermined correlation threshold to allow the GPS signal to be fully acquired and tracked.

Development and evaluation of a local grid refinement method for block-centered finite-difference groundwater models using shared nodes

USGS Publications Warehouse

Mehl, S.; Hill, M.C.

2002-01-01

A new method of local grid refinement for two-dimensional block-centered finite-difference meshes is presented in the context of steady-state groundwater-flow modeling. The method uses an iteration-based feedback with shared nodes to couple two separate grids. The new method is evaluated by comparison with results using a uniform fine mesh, a variably spaced mesh, and a traditional method of local grid refinement without a feedback. Results indicate: (1) The new method exhibits quadratic convergence for homogeneous systems and convergence equivalent to uniform-grid refinement for heterogeneous systems. (2) Coupling the coarse grid with the refined grid in a numerically rigorous way allowed for improvement in the coarse-grid results. (3) For heterogeneous systems, commonly used linear interpolation of heads from the large model onto the boundary of the refined model produced heads that are inconsistent with the physics of the flow field. (4) The traditional method works well in situations where the better resolution of the locally refined grid has little influence on the overall flow-system dynamics, but if this is not true, lack of a feedback mechanism produced errors in head up to 3.6% and errors in cell-to-cell flows up to 25%. ?? 2002 Elsevier Science Ltd. All rights reserved.

Grid-Level Application of Electrical Energy Storage: Example Use Cases in the United States and China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yingchen; Gevorgian, Vahan; Wang, Caixia

Electrical energy storage (EES) systems are expected to play an increasing role in helping the United States and China-the world's largest economies with the two largest power systems-meet the challenges of integrating more variable renewable resources and enhancing the reliability of power systems by improving the operating capabilities of the electric grid. EES systems are becoming integral components of a resilient and efficient grid through a diverse set of applications that include energy management, load shifting, frequency regulation, grid stabilization, and voltage support.

The Design of Distributed Micro Grid Energy Storage System

NASA Astrophysics Data System (ADS)

Liang, Ya-feng; Wang, Yan-ping

2018-03-01

Distributed micro-grid runs in island mode, the energy storage system is the core to maintain the micro-grid stable operation. For the problems that it is poor to adjust at work and easy to cause the volatility of micro-grid caused by the existing energy storage structure of fixed connection. In this paper, an array type energy storage structure is proposed, and the array type energy storage system structure and working principle are analyzed. Finally, the array type energy storage structure model is established based on MATLAB, the simulation results show that the array type energy storage system has great flexibility, which can maximize the utilization of energy storage system, guarantee the reliable operation of distributed micro-grid and achieve the function of peak clipping and valley filling.

Earth Science Data Grid System

NASA Astrophysics Data System (ADS)

Chi, Y.; Yang, R.; Kafatos, M.

2004-05-01

The Earth Science Data Grid System (ESDGS) is a software system in support of earth science data storage and access. It is built upon the Storage Resource Broker (SRB) data grid technology. We have developed a complete data grid system consistent of SRB server providing users uniform access to diverse storage resources in a heterogeneous computing environment and metadata catalog server (MCAT) managing the metadata associated with data set, users, and resources. We also develop the earth science application metadata; geospatial, temporal, and content-based indexing; and some other tools. In this paper, we will describe software architecture and components of the data grid system, and use a practical example in support of storage and access of rainfall data from the Tropical Rainfall Measuring Mission (TRMM) to illustrate its functionality and features.

GridAPPS-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-03-28

GridAPPS-D is an open-source, open architecture, standards based platform for development of advanced electric power system planning and operations applications. GridAPPS-D provides a documented data abstraction for the application developer enabling creation of applications that can be run in any compliant system or platform. This enables development of applications that are platform vendor independent applications and applications that take advantage of the possibility of data rich and data driven applications based on deployment of smart grid devices and systems.

Grid-translation beam deflection systems for 5-cm and 30-cm diameter Kaufman thrusters.

NASA Technical Reports Server (NTRS)

Lathem, W. C.

1972-01-01

A 5-cm grid translation mechanism has been developed capable of 10-deg beam deflection. A 2026-hour endurance test was run at a preset 10-deg deflection angle, and an extrapolated lifetime of better than 10,000 hours was obtained. Response time data for grid translation are presented. Preliminary results for a 30-cm diameter system are given, and results of a theoretical analysis of a dished grid system are discussed.

Grid-translation beam deflection systems for 5-cm and 30-cm diameter Kaufman thrusters

NASA Technical Reports Server (NTRS)

Lathem, W. C.

1972-01-01

A 5-cm grid translation mechanism has been developed capable of 10 deg beam deflection. A 2026-hour endurance test was run at a preset 10 deg deflection angle and an extrapolated lifetime of better than 10,000 hours obtained. Response time data for grid translation are presented. Preliminary results for a 30-cm diameter system are given and results of a theoretical analysis of a dished grid system are discussed.

Ion beamlet steering for two-grid electrostatic thrusters. M.S. Thesis

NASA Technical Reports Server (NTRS)

Homa, J. M.

1984-01-01

An experimental study of ion beamlet steering in which the direction of beamlets emitted from a two grid aperture system is controlled by relative translation of the grids, is described. The results can be used to design electrostatic accelerating devices for which the direction and focus of emerging beamlets are important. Deflection and divergence angle data are presented for two grid systems as a function of the relative lateral displacement of the holes in these grids. At large displacements, accelerator grid impingements become excessive and this determines the maximum allowable displacement and as a result the useful range of beamlet deflection. Beamlet deflection is shown to vary linearly with grid offset angle over this range. The divergence of the beamlets is found to be unaffected by deflection over the useful range of beamlet deflection. The grids of a typical dished grid ion thruster are examined to determine the effects of thermally induced grid distortion and prescribed offsets of grid hole centerlines on the characteristics of the emerging beamlets. The results are used to determine the region on the grid surface where ion beamlet deflections exceed the useful range. Over this region high accelerator grid impingement currents and rapid grid erosion are predicted.

Grid cell spatial tuning reduced following systemic muscarinic receptor blockade

PubMed Central

Newman, Ehren L.; Climer, Jason R.; Hasselmo, Michael E.

2014-01-01

Grid cells of the medial entorhinal cortex exhibit a periodic and stable pattern of spatial tuning that may reflect the output of a path integration system. This grid pattern has been hypothesized to serve as a spatial coordinate system for navigation and memory function. The mechanisms underlying the generation of this characteristic tuning pattern remain poorly understood. Systemic administration of the muscarinic antagonist scopolamine flattens the typically positive correlation between running speed and entorhinal theta frequency in rats. The loss of this neural correlate of velocity, an important signal for the calculation of path integration, raises the question of what influence scopolamine has on the grid cell tuning as a read out of the path integration system. To test this, the spatial tuning properties of grid cells were compared before and after systemic administration of scopolamine as rats completed laps on a circle track for food rewards. The results show that the spatial tuning of the grid cells was reduced following scopolamine administration. The tuning of head direction cells, in contrast, was not reduced by scopolamine. This is the first report to demonstrate a link between cholinergic function and grid cell tuning. This work suggests that the loss of tuning in the grid cell network may underlie the navigational disorientation observed in Alzheimer's patients and elderly individuals with reduced cholinergic tone. PMID:24493379

Wireless Communications in Smart Grid

NASA Astrophysics Data System (ADS)

Bojkovic, Zoran; Bakmaz, Bojan

Communication networks play a crucial role in smart grid, as the intelligence of this complex system is built based on information exchange across the power grid. Wireless communications and networking are among the most economical ways to build the essential part of the scalable communication infrastructure for smart grid. In particular, wireless networks will be deployed widely in the smart grid for automatic meter reading, remote system and customer site monitoring, as well as equipment fault diagnosing. With an increasing interest from both the academic and industrial communities, this chapter systematically investigates recent advances in wireless communication technology for the smart grid.

HOMAR: A computer code for generating homotopic grids using algebraic relations: User's manual

NASA Technical Reports Server (NTRS)

Moitra, Anutosh

1989-01-01

A computer code for fast automatic generation of quasi-three-dimensional grid systems for aerospace configurations is described. The code employs a homotopic method to algebraically generate two-dimensional grids in cross-sectional planes, which are stacked to produce a three-dimensional grid system. Implementation of the algebraic equivalents of the homotopic relations for generating body geometries and grids are explained. Procedures for controlling grid orthogonality and distortion are described. Test cases with description and specification of inputs are presented in detail. The FORTRAN computer program and notes on implementation and use are included.

Status Report on Modelling and Simulation Capabilities for Nuclear-Renewable Hybrid Energy Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rabiti, C.; Epiney, A.; Talbot, P.

This report summarizes the current status of the modeling and simulation capabilities developed for the economic assessment of Nuclear-Renewable Hybrid Energy Systems (N-R HES). The increasing penetration of variable renewables is altering the profile of the net demand, with which the other generators on the grid have to cope. N-R HES analyses are being conducted to determine the potential feasibility of mitigating the resultant volatility in the net electricity demand by adding industrial processes that utilize either thermal or electrical energy as stabilizing loads. This coordination of energy generators and users is proposed to mitigate the increase in electricity costmore » and cost volatility through the production of a saleable commodity. Overall, the financial performance of a system that is comprised of peaking units (i.e. gas turbine), baseload supply (i.e. nuclear power plant), and an industrial process (e.g. hydrogen plant) should be optimized under the constraint of satisfying an electricity demand profile with a certain level of variable renewable (wind) penetration. The optimization should entail both the sizing of the components/subsystems that comprise the system and the optimal dispatch strategy (output at any given moment in time from the different subsystems). Some of the capabilities here described have been reported separately in [1, 2, 3]. The purpose of this report is to provide an update on the improvement and extension of those capabilities and to illustrate their integrated application in the economic assessment of N-R HES.« less

Homogeneity and EPR metrics for assessment of regular grids used in CW EPR powder simulations.

PubMed

Crăciun, Cora

2014-08-01

CW EPR powder spectra may be approximated numerically using a spherical grid and a Voronoi tessellation-based cubature. For a given spin system, the quality of simulated EPR spectra depends on the grid type, size, and orientation in the molecular frame. In previous work, the grids used in CW EPR powder simulations have been compared mainly from geometric perspective. However, some grids with similar homogeneity degree generate different quality simulated spectra. This paper evaluates the grids from EPR perspective, by defining two metrics depending on the spin system characteristics and the grid Voronoi tessellation. The first metric determines if the grid points are EPR-centred in their Voronoi cells, based on the resonance magnetic field variations inside these cells. The second metric verifies if the adjacent Voronoi cells of the tessellation are EPR-overlapping, by computing the common range of their resonance magnetic field intervals. Beside a series of well known regular grids, the paper investigates a modified ZCW grid and a Fibonacci spherical code, which are new in the context of EPR simulations. For the investigated grids, the EPR metrics bring more information than the homogeneity quantities and are better related to the grids' EPR behaviour, for different spin system symmetries. The metrics' efficiency and limits are finally verified for grids generated from the initial ones, by using the original or magnetic field-constraint variants of the Spherical Centroidal Voronoi Tessellation method. Copyright © 2014 Elsevier Inc. All rights reserved.

Brief analysis of Jiangsu grid security and stability based on multi-infeed DC index in power system

NASA Astrophysics Data System (ADS)

Zhang, Wenjia; Wang, Quanquan; Ge, Yi; Huang, Junhui; Chen, Zhengfang

2018-02-01

The impact of Multi-infeed HVDC has gradually increased to security and stability operating in Jiangsu power grid. In this paper, an appraisal method of Multi-infeed HVDC power grid security and stability is raised with Multi-Infeed Effective Short Circuit Ratio, Multi-Infeed Interaction Factor and Commutation Failure Immunity Index. These indices are adopted in security and stability simulating calculation of Jiangsu Multi-infeed HVDC system. The simulation results indicate that Jiangsu power grid is operating with a strong DC system. It has high level of power grid security and stability, and meet the safety running requirements. Jinpin-Suzhou DC system is located in the receiving end with huge capacity, which is easily leading to commutation failure of the transmission line. In order to resolve this problem, dynamic reactive power compensation can be applied in power grid near Jinpin-Suzhou DC system. Simulation result shows this method is feasible to commutation failure.

Distributed data mining on grids: services, tools, and applications.

PubMed

Cannataro, Mario; Congiusta, Antonio; Pugliese, Andrea; Talia, Domenico; Trunfio, Paolo

2004-12-01

Data mining algorithms are widely used today for the analysis of large corporate and scientific datasets stored in databases and data archives. Industry, science, and commerce fields often need to analyze very large datasets maintained over geographically distributed sites by using the computational power of distributed and parallel systems. The grid can play a significant role in providing an effective computational support for distributed knowledge discovery applications. For the development of data mining applications on grids we designed a system called Knowledge Grid. This paper describes the Knowledge Grid framework and presents the toolset provided by the Knowledge Grid for implementing distributed knowledge discovery. The paper discusses how to design and implement data mining applications by using the Knowledge Grid tools starting from searching grid resources, composing software and data components, and executing the resulting data mining process on a grid. Some performance results are also discussed.

Optically-sectioned two-shot structured illumination microscopy with Hilbert-Huang processing.

PubMed

Patorski, Krzysztof; Trusiak, Maciej; Tkaczyk, Tomasz

2014-04-21

We introduce a fast, simple, adaptive and experimentally robust method for reconstructing background-rejected optically-sectioned images using two-shot structured illumination microscopy. Our innovative data demodulation method needs two grid-illumination images mutually phase shifted by π (half a grid period) but precise phase displacement between two frames is not required. Upon frames subtraction the input pattern with increased grid modulation is obtained. The first demodulation stage comprises two-dimensional data processing based on the empirical mode decomposition for the object spatial frequency selection (noise reduction and bias term removal). The second stage consists in calculating high contrast image using the two-dimensional spiral Hilbert transform. Our algorithm effectiveness is compared with the results calculated for the same input data using structured-illumination (SIM) and HiLo microscopy methods. The input data were collected for studying highly scattering tissue samples in reflectance mode. Results of our approach compare very favorably with SIM and HiLo techniques.

Smart grid technologies in local electric grids

NASA Astrophysics Data System (ADS)

Lezhniuk, Petro D.; Pijarski, Paweł; Buslavets, Olga A.

2017-08-01

The research is devoted to the creation of favorable conditions for the integration of renewable sources of energy into electric grids, which were designed to be supplied from centralized generation at large electric power stations. Development of distributed generation in electric grids influences the conditions of their operation - conflict of interests arises. The possibility of optimal functioning of electric grids and renewable sources of energy, when complex criterion of the optimality is balance reliability of electric energy in local electric system and minimum losses of electric energy in it. Multilevel automated system for power flows control in electric grids by means of change of distributed generation of power is developed. Optimization of power flows is performed by local systems of automatic control of small hydropower stations and, if possible, solar power plants.

Analyzing Effect of System Inertia on Grid Frequency Forecasting Usnig Two Stage Neuro-Fuzzy System

NASA Astrophysics Data System (ADS)

Chourey, Divyansh R.; Gupta, Himanshu; Kumar, Amit; Kumar, Jitesh; Kumar, Anand; Mishra, Anup

2018-04-01

Frequency forecasting is an important aspect of power system operation. The system frequency varies with load-generation imbalance. Frequency variation depends upon various parameters including system inertia. System inertia determines the rate of fall of frequency after the disturbance in the grid. Though, inertia of the system is not considered while forecasting the frequency of power system during planning and operation. This leads to significant errors in forecasting. In this paper, the effect of inertia on frequency forecasting is analysed for a particular grid system. In this paper, a parameter equivalent to system inertia is introduced. This parameter is used to forecast the frequency of a typical power grid for any instant of time. The system gives appreciable result with reduced error.

Energy Systems Integration: Demonstrating Distribution Feeder Voltage Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-01-01

Overview fact sheet about the Smarter Grid Solutions Integrated Network Testbed for Energy Grid Research and Technology Experimentation (INTEGRATE) project at the Energy Systems Integration Facility. INTEGRATE is part of the U.S. Department of Energy's Grid Modernization Initiative.

Energy Systems Integration: Demonstrating Distributed Grid-Edge Control Hierarchy

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-01-01

Overview fact sheet about the OMNETRIC Group Integrated Network Testbed for Energy Grid Research and Technology Experimentation (INTEGRATE) project at the Energy Systems Integration Facility. INTEGRATE is part of the U.S. Department of Energy's Grid Modernization Initiative.

GridTool: A surface modeling and grid generation tool

NASA Technical Reports Server (NTRS)

Samareh-Abolhassani, Jamshid

1995-01-01

GridTool is designed around the concept that the surface grids are generated on a set of bi-linear patches. This type of grid generation is quite easy to implement, and it avoids the problems associated with complex CAD surface representations and associated surface parameterizations. However, the resulting surface grids are close to but not on the original CAD surfaces. This problem can be alleviated by projecting the resulting surface grids onto the original CAD surfaces. GridTool is designed primary for unstructured grid generation systems. Currently, GridTool supports VGRID and FELISA systems, and it can be easily extended to support other unstructured grid generation systems. The data in GridTool is stored parametrically so that once the problem is set up, one can modify the surfaces and the entire set of points, curves and patches will be updated automatically. This is very useful in a multidisciplinary design and optimization process. GridTool is written entirely in ANSI 'C', the interface is based on the FORMS library, and the graphics is based on the GL library. The code has been tested successfully on IRIS workstations running IRIX4.0 and above. The memory is allocated dynamically, therefore, memory size will depend on the complexity of geometry/grid. GridTool data structure is based on a link-list structure which allows the required memory to expand and contract dynamically according to the user's data size and action. Data structure contains several types of objects such as points, curves, patches, sources and surfaces. At any given time, there is always an active object which is drawn in magenta, or in their highlighted colors as defined by the resource file which will be discussed later.

Experiences of engineering Grid-based medical software.

PubMed

Estrella, F; Hauer, T; McClatchey, R; Odeh, M; Rogulin, D; Solomonides, T

2007-08-01

Grid-based technologies are emerging as potential solutions for managing and collaborating distributed resources in the biomedical domain. Few examples exist, however, of successful implementations of Grid-enabled medical systems and even fewer have been deployed for evaluation in practice. The objective of this paper is to evaluate the use in clinical practice of a Grid-based imaging prototype and to establish directions for engineering future medical Grid developments and their subsequent deployment. The MammoGrid project has deployed a prototype system for clinicians using the Grid as its information infrastructure. To assist in the specification of the system requirements (and for the first time in healthgrid applications), use-case modelling has been carried out in close collaboration with clinicians and radiologists who had no prior experience of this modelling technique. A critical qualitative and, where possible, quantitative analysis of the MammoGrid prototype is presented leading to a set of recommendations from the delivery of the first deployed Grid-based medical imaging application. We report critically on the application of software engineering techniques in the specification and implementation of the MammoGrid project and show that use-case modelling is a suitable vehicle for representing medical requirements and for communicating effectively with the clinical community. This paper also discusses the practical advantages and limitations of applying the Grid to real-life clinical applications and presents the consequent lessons learned. The work presented in this paper demonstrates that given suitable commitment from collaborating radiologists it is practical to deploy in practice medical imaging analysis applications using the Grid but that standardization in and stability of the Grid software is a necessary pre-requisite for successful healthgrids. The MammoGrid prototype has therefore paved the way for further advanced Grid-based deployments in the medical and biomedical domains.

Variability of 137Cs inventory at a reference site in west-central Iran.

PubMed

Bazshoushtari, Nasim; Ayoubi, Shamsollah; Abdi, Mohammad Reza; Mohammadi, Mohammad

2016-12-01

137 Cs technique has been widely used for the evaluation rates and patterns of soil erosion and deposition. This technique requires an accurate estimate of the values of 137 Cs inventory at the reference site. This study was conducted to evaluate the variability of the inventory of 137 Cs regarding to the sampling program including sample size, distance and sampling method at a reference site located in vicinity of Fereydan district in Isfahan province, west-central Iran. Two 3 × 8 grids were established comprising large grid (35 m length and 8 m width), and small grid (24 m length and 6 m width). At each grid intersection two soil samples were collected from 0 to 15 cm and 15-30 cm depths, totally 96 soil samples from 48 sampling points. Coefficients of variation for 137 Cs inventory in the soil samples was relatively low (CV = 15%), and the sampling distance and methods used did not significantly affect the 137 Cs inventories across the studied reference site. To obtain a satisfactory estimate of the mean 137 Cs activity in the reference sites, particularly those located in the semiarid regions, it is recommended to collect at least four samples along in a grid pattern 3 m apart. Copyright © 2016 Elsevier Ltd. All rights reserved.

Broad-band beam buncher

DOEpatents

Goldberg, David A.; Flood, William S.; Arthur, Allan A.; Voelker, Ferdinand

1986-01-01

A broad-band beam buncher is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-band response and the device as a whole designed to effect broad-band beam coupling, so as to minimize variations of the output across the response band.

Impacts of the transformation of the German energy system on the transmission grid

NASA Astrophysics Data System (ADS)

Pesch, T.; Allelein, H.-J.; Hake, J.-F.

2014-10-01

The German Energiewende, the transformation of the energy system, has deep impacts on all parts of the system. This paper presents an approach that has been developed to simultaneously analyse impacts on the energy system as a whole and on the electricity system in particular. In the analysis, special emphasis is placed on the transmission grid and the efficiency of recommended grid extensions according to the German Network Development Plan. The analysis reveals that the measures in the concept are basically suitable for integrating the assumed high share of renewables in the future electricity system. Whereas a high feed-in from PV will not cause problems in the transmission grid in 2022, congestion may occur in situations with a high proportion of wind feed-in. Moreover, future bottlenecks in the grid are located in the same regions as today.

Grid regulation services for energy storage devices based on grid frequency

DOEpatents

Pratt, Richard M; Hammerstrom, Donald J; Kintner-Meyer, Michael C.W.; Tuffner, Francis K

2013-07-02

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Grid regulation services for energy storage devices based on grid frequency

DOEpatents

Pratt, Richard M.; Hammerstrom, Donald J.; Kintner-Meyer, Michael C. W.; Tuffner, Francis K.

2017-09-05

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Grid regulation services for energy storage devices based on grid frequency

DOEpatents

Pratt, Richard M; Hammerstrom, Donald J; Kintner-Meyer, Michael C.W.; Tuffner, Francis K

2014-04-15

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Use of Fuzzy Logic Systems for Assessment of Primary Faults

NASA Astrophysics Data System (ADS)

Petrović, Ivica; Jozsa, Lajos; Baus, Zoran

2015-09-01

In electric power systems, grid elements are often subjected to very complex and demanding disturbances or dangerous operating conditions. Determining initial fault or cause of those states is a difficult task. When fault occurs, often it is an imperative to disconnect affected grid element from the grid. This paper contains an overview of possibilities for using fuzzy logic in an assessment of primary faults in the transmission grid. The tool for this task is SCADA system, which is based on information of currents, voltages, events of protection devices and status of circuit breakers in the grid. The function model described with the membership function and fuzzy logic systems will be presented in the paper. For input data, diagnostics system uses information of protection devices tripping, states of circuit breakers and measurements of currents and voltages before and after faults.

Laminated grid and web magnetic cores

DOEpatents

Sefko, John; Pavlik, Norman M.

1984-01-01

A laminated magnetic core characterized by an electromagnetic core having core legs which comprise elongated apertures and edge notches disposed transversely to the longitudinal axis of the legs, such as high reluctance cores with linear magnetization characteristics for high voltage shunt reactors. In one embodiment the apertures include compact bodies of microlaminations for more flexibility and control in adjusting permeability and/or core reluctance.

An overview of controls research on the NASA Langley Research Center grid

NASA Technical Reports Server (NTRS)

Montgomery, Raymond C.

1987-01-01

The NASA Langley Research Center has assembled a flexible grid on which control systems research can be accomplished on a two-dimensional structure that has many physically distributed sensors and actuators. The grid is a rectangular planar structure that is suspended by two cables attached to one edge so that out of plane vibrations are normal to gravity. There are six torque wheel actuators mounted to it so that torque is produced in the grid plane. Also, there are six rate gyros mounted to sense angular motion in the grid plane and eight accelerometers that measure linear acceleration normal to the grid plane. All components can be relocated to meet specific control system test requirements. Digital, analog, and hybrid control systems capability is provided in the apparatus. To date, research on this grid has been conducted in the areas of system and parameter identification, model estimation, distributed modal control, hierarchical adaptive control, and advanced redundancy management algorithms. The presentation overviews each technique and presents the most significant results generated for each area.

AVQS: Attack Route-Based Vulnerability Quantification Scheme for Smart Grid

PubMed Central

Lim, Hyunwoo; Lee, Seokjun; Shon, Taeshik

2014-01-01

A smart grid is a large, consolidated electrical grid system that includes heterogeneous networks and systems. Based on the data, a smart grid system has a potential security threat in its network connectivity. To solve this problem, we develop and apply a novel scheme to measure the vulnerability in a smart grid domain. Vulnerability quantification can be the first step in security analysis because it can help prioritize the security problems. However, existing vulnerability quantification schemes are not suitable for smart grid because they do not consider network vulnerabilities. We propose a novel attack route-based vulnerability quantification scheme using a network vulnerability score and an end-to-end security score, depending on the specific smart grid network environment to calculate the vulnerability score for a particular attack route. To evaluate the proposed approach, we derive several attack scenarios from the advanced metering infrastructure domain. The experimental results of the proposed approach and the existing common vulnerability scoring system clearly show that we need to consider network connectivity for more optimized vulnerability quantification. PMID:25152923

On automating domain connectivity for overset grids

NASA Technical Reports Server (NTRS)

Chiu, Ing-Tsau; Meakin, Robert L.

1995-01-01

An alternative method for domain connectivity among systems of overset grids is presented. Reference uniform Cartesian systems of points are used to achieve highly efficient domain connectivity, and form the basis for a future fully automated system. The Cartesian systems are used to approximate body surfaces and to map the computational space of component grids. By exploiting the characteristics of Cartesian systems, Chimera type hole-cutting and identification of donor elements for intergrid boundary points can be carried out very efficiently. The method is tested for a range of geometrically complex multiple-body overset grid systems. A dynamic hole expansion/contraction algorithm is also implemented to obtain optimum domain connectivity; however, it is tested only for geometry of generic shapes.

Current Grid operation and future role of the Grid

NASA Astrophysics Data System (ADS)

Smirnova, O.

2012-12-01

Grid-like technologies and approaches became an integral part of HEP experiments. Some other scientific communities also use similar technologies for data-intensive computations. The distinct feature of Grid computing is the ability to federate heterogeneous resources of different ownership into a seamless infrastructure, accessible via a single log-on. Like other infrastructures of similar nature, Grid functioning requires not only technologically sound basis, but also reliable operation procedures, monitoring and accounting. The two aspects, technological and operational, are closely related: weaker is the technology, more burden is on operations, and other way around. As of today, Grid technologies are still evolving: at CERN alone, every LHC experiment uses an own Grid-like system. This inevitably creates a heavy load on operations. Infrastructure maintenance, monitoring and incident response are done on several levels, from local system administrators to large international organisations, involving massive human effort worldwide. The necessity to commit substantial resources is one of the obstacles faced by smaller research communities when moving computing to the Grid. Moreover, most current Grid solutions were developed under significant influence of HEP use cases, and thus need additional effort to adapt them to other applications. Reluctance of many non-HEP researchers to use Grid negatively affects the outlook for national Grid organisations, which strive to provide multi-science services. We started from the situation where Grid organisations were fused with HEP laboratories and national HEP research programmes; we hope to move towards the world where Grid will ultimately reach the status of generic public computing and storage service provider and permanent national and international Grid infrastructures will be established. How far will we be able to advance along this path, depends on us. If no standardisation and convergence efforts will take place, Grid will become limited to HEP; if however the current multitude of Grid-like systems will converge to a generic, modular and extensible solution, Grid will become true to its name.

Concentrated solar power plants impact on PV penetration level and grid flexibility under Egyptian climate

NASA Astrophysics Data System (ADS)

Moukhtar, Ibrahim; Elbaset, Adel A.; El Dein, Adel Z.; Qudaih, Yaser; Mitani, Yasunori

2018-05-01

Photovoltaic (PV) system integration in the electric grid has been increasing over the past decades. However, the impact of PV penetration on the electric grid, especially during the periods of higher and lower generation for the solar system at the middle of the day and during cloudy weather or at night respectively, limit the high penetration of solar PV system. In this research, a Concentrated Solar Power (CSP) with Thermal Energy Storage (TES) has been aggregated with PV system in order to accommodate the required electrical power during the higher and lower solar energy at all timescales. This paper analyzes the impacts of CSP on the grid-connected PV considering high penetration of PV system, particularly when no energy storages in the form of batteries are used. Two cases have been studied, the first when only PV system is integrated into the electric grid and the second when two types of solar energy (PV and CSP) are integrated. The System Advisor Model (SAM) software is used to simulate the output power of renewable energy. Simulation results show that the performance of CSP has a great impact on the penetration level of PV system and on the flexibility of the electric grid. The overall grid flexibility increases due to the ability of CSP to store and dispatch the generated power. In addition, CSP/TES itself has inherent flexibility. Therefore, CSP reduces the minimum generation constraint of the conventional generators that allows more penetration of the PV system.

WegenerNet climate station network region Feldbach/Austria: From local measurements to weather and climate data products at 1 km-scale resolution

NASA Astrophysics Data System (ADS)

Kabas, T.; Leuprecht, A.; Bichler, C.; Kirchengast, G.

2010-12-01

South-eastern Austria is characteristic for experiencing a rich variety of weather and climate patterns. For this reason, the county of Feldbach was selected by the Wegener Center as a focus area for a pioneering observation experiment at very high resolution: The WegenerNet climate station network (in brief WegenerNet) comprises 151 meteorological stations within an area of about 20 km × 15 km (~ 1.4 km × 1.4 km station grid). All stations measure the main parameters temperature, humidity and precipitation with 5 minute sampling. Selected further stations include measurements of wind speed and direction completed by soil parameters as well as air pressure and net radiation. The collected data is integrated in an automatic processing system including data transfer, quality control, product generation, and visualization. Each station is equipped with an internet-attached data logger and the measurements are transferred as binary files via GPRS to the WegenerNet server in 1 hour intervals. The incoming raw data files of measured parameters as well as several operating values of the data logger are stored in a relational database (PostgreSQL). Next, the raw data pass the Quality Control System (QCS) in which the data are checked for its technical and physical plausibility (e.g., sensor specifications, temporal and spatial variability). In consideration of the data quality (quality flag), the Data Product Generator (DPG) results in weather and climate data products on various temporal scales (from 5 min to annual) for single stations and regular grids. Gridded data are derived by vertical scaling and squared inverse distance interpolation (1 km × 1 km and 0.01° × 0.01° grids). Both subsystems (QCS and DPG) are realized by the programming language Python. For application purposes the resulting data products are available via the bi-lingual (dt, en) WegenerNet data portal (www.wegenernet.org). At this time, the main interface is still online in a system in which MapServer is used to import spatial data by its database interface and to generate images of static geographic formats. However, a Java applet is additionally needed to display these images on the users local host. Furthermore, station data are visualized as time series by the scripting language PHP. Since February 2010, the visualization of gridded data products is a first step to a new data portal based on OpenLayers. In this GIS framework, all geographic information (e.g., OpenStreetMap) is displayed with MapServer. Furthermore, the visualization of all meteorological parameters are generated on the fly by a Python CGI script and transparently overlayed on the maps. Hence, station data and gridded data are visualized and further prepared for download in common data formats (csv, NetCDF). In conclusion, measured data and generated data products are provided with a data latency less than 1-2 hours in standard operation (near real time). Following an introduction of the processing system along the lines above, resulting data products are presented online at the WegenerNet data portal.

An interactive multi-block grid generation system

NASA Technical Reports Server (NTRS)

Kao, T. J.; Su, T. Y.; Appleby, Ruth

1992-01-01

A grid generation procedure combining interactive and batch grid generation programs was put together to generate multi-block grids for complex aircraft configurations. The interactive section provides the tools for 3D geometry manipulation, surface grid extraction, boundary domain construction for 3D volume grid generation, and block-block relationships and boundary conditions for flow solvers. The procedure improves the flexibility and quality of grid generation to meet the design/analysis requirements.

Dynamic fisheye grids for binary black hole simulations

NASA Astrophysics Data System (ADS)

Zilhão, Miguel; Noble, Scott C.

2014-03-01

We present a new warped gridding scheme adapted to simulating gas dynamics in binary black hole spacetimes. The grid concentrates grid points in the vicinity of each black hole to resolve the smaller scale structures there, and rarefies grid points away from each black hole to keep the overall problem size at a practical level. In this respect, our system can be thought of as a ‘double’ version of the fisheye coordinate system, used before in numerical relativity codes for evolving binary black holes. The gridding scheme is constructed as a mapping between a uniform coordinate system—in which the equations of motion are solved—to the distorted system representing the spatial locations of our grid points. Since we are motivated to eventually use this system for circumbinary disc calculations, we demonstrate how the distorted system can be constructed to asymptote to the typical spherical polar coordinate system, amenable to efficiently simulating orbiting gas flows about central objects with little numerical diffusion. We discuss its implementation in the Harm3d code, tailored to evolve the magnetohydrodynamics equations in curved spacetimes. We evaluate the performance of the system’s implementation in Harm3d with a series of tests, such as the advected magnetic field loop test, magnetized Bondi accretion, and evolutions of hydrodynamic discs about a single black hole and about a binary black hole. Like we have done with Harm3d, this gridding scheme can be implemented in other unigrid codes as a (possibly) simpler alternative to adaptive mesh refinement.

Battery with modular air cathode and anode cage

DOEpatents

Niksa, Marilyn J.; Pohto, Gerald R.; Lakatos, Leslie K.; Wheeler, Douglas J.; Niksa, Andrew J.; Schue, Thomas J.

1987-01-01

A battery assembly of the consumable metal anode type has now been constructed for ready assembly as well as disassembly. In a non-conductive and at least substantially inert cell body, space is provided for receiving an open-structured, non-consumable anode cage. The cage has an open top for facilitating insertion of an anode. A modular cathode is used, comprising a peripheral current conductor frame clamped about a grid reinforced air cathode in sheet form. The air cathode may be double gridded. The cathode frame can be sealed, during assembly, with electrolyte-resistant-sealant as well as with adhesive. The resulting cathode module can be assembled outside the cell body and readily inserted therein, or can later be easily removed therefrom.

Battery with modular air cathode and anode cage

DOEpatents

Niksa, Marilyn J.; Pohto, Gerald R.; Lakatos, Leslie K.; Wheeler, Douglas J.; Niksa, Andrew J.; Schue, Thomas J.; Turk, Thomas R.

1988-01-01

A battery assembly of the consumable metal anode type has now been constructed for ready assembly as well as disassembly. In a non-conductive and at least substantially inert cell body, space is provided for receiving an open-structured, non-consumable anode cage. The cage has an open top for facilitating insertion of an anode. A modular cathode is used, comprising a peripheral current conductor frame clamped about a grid reinforced air cathode in sheet form. The air cathode may be double gridded. The cathode frame can be sealed, during assembly, with electrolyte-resistant-sealant as well as with adhesive. The resulting cathode module can be assembled outside the cell body and readily inserted therein, or can later be easily removed therefrom.

Method of making a unitized electrode assembly

DOEpatents

Niksa, Marilyn J.; Pohto, Gerald R.; Lakatos, Leslie K.; Wheeler, Douglas J.; Solomon, Frank; Niksa, Andrew J.; Schue, Thomas J.; Genodman, Yury; Turk, Thomas R.; Hagel, Daniel P.

1988-01-01

A battery assembly of the consumable metal anode type has now been constructed for ready assembly as well as disassembly. In a non-conductive and at least substantially inert cell body, space is provided for receiving an open-structured, non-consumable anode cage. The cage has an open top for facilitating insertion of an anode. A modular cathode is used, comprising a peripheral current conductor frame clamped about a grid reinforced air cathode in sheet form. The air cathode may be double gridded. The cathode frame can be sealed, during assembly, with electrolyte-resistant-sealant as well as with adhesive. The resulting cathode module can be assembled outside the cell body and readily inserted therein, or can later be easily removed therefrom.

Method of making a unitized electrode assembly

DOEpatents

Niksa, M.J.; Pohto, G.R.; Lakatos, L.K.; Wheeler, D.J.; Solomon, F.; Niksa, A.J.; Schue, T.J.; Genodman, Y.; Turk, T.R.; Hagel, D.P.

1988-12-06

A battery assembly of the consumable metal anode type has now been constructed for ready assembly as well as disassembly. In a non-conductive and at least substantially inert cell body, space is provided for receiving an open-structured, non-consumable anode cage. The cage has an open top for facilitating insertion of an anode. A modular cathode is used, comprising a peripheral current conductor frame clamped about a grid reinforced air cathode in sheet form. The air cathode may be double gridded. The cathode frame can be sealed, during assembly, with electrolyte-resistant-sealant as well as with adhesive. The resulting cathode module can be assembled outside the cell body and readily inserted therein, or can later be easily removed therefrom. 6 figs.

Self-modulating pressure gauge

DOEpatents

Edwards, D. Jr.; Lanni, C.P.

1979-08-07

An ion gauge is disclosed having a reduced x-ray limit and means for measuring that limit. The gauge comprises an ion gauge of the Bayard-Alpert type having a short collector and having means for varying the grid-collector voltage. The x-ray limit (i.e. the collector current resulting from x-rays striking the collector) may then be determined by the formula: I/sub x/ = ..cap alpha..I/sub l/ - I/sub h//..cap alpha.. - l where: I/sub x/ = x-ray limit, I/sub l/ and I/sub h/ = the collector current at the lower and higher grid voltage respectively; and, ..cap alpha.. = the ratio of the collector current due to positive ions at the higher voltage to that at the lower voltage.

Micro-grid platform based on NODE.JS architecture, implemented in electrical network instrumentation

NASA Astrophysics Data System (ADS)

Duque, M.; Cando, E.; Aguinaga, A.; Llulluna, F.; Jara, N.; Moreno, T.

2016-05-01

In this document, I propose a theory about the impact of systems based on microgrids in non-industrialized countries that have the goal to improve energy exploitation through alternatives methods of a clean and renewable energy generation and the creation of the app to manage the behavior of the micro-grids based on the NodeJS, Django and IOJS technologies. The micro-grids allow the optimal way to manage energy flow by electric injection directly in electric network small urban's cells in a low cost and available way. In difference from conventional systems, micro-grids can communicate between them to carry energy to places that have higher demand in accurate moments. This system does not require energy storage, so, costs are lower than conventional systems like fuel cells, solar panels or else; even though micro-grids are independent systems, they are not isolated. The impact that this analysis will generate, is the improvement of the electrical network without having greater control than an intelligent network (SMART-GRID); this leads to move to a 20% increase in energy use in a specified network; that suggest there are others sources of energy generation; but for today's needs, we need to standardize methods and remain in place to support all future technologies and the best option are the Smart Grids and Micro-Grids.

GENIE(++): A Multi-Block Structured Grid System

NASA Technical Reports Server (NTRS)

Williams, Tonya; Nadenthiran, Naren; Thornburg, Hugh; Soni, Bharat K.

1996-01-01

The computer code GENIE++ is a continuously evolving grid system containing a multitude of proven geometry/grid techniques. The generation process in GENIE++ is based on an earlier version. The process uses several techniques either separately or in combination to quickly and economically generate sculptured geometry descriptions and grids for arbitrary geometries. The computational mesh is formed by using an appropriate algebraic method. Grid clustering is accomplished with either exponential or hyperbolic tangent routines which allow the user to specify a desired point distribution. Grid smoothing can be accomplished by using an elliptic solver with proper forcing functions. B-spline and Non-Uniform Rational B-splines (NURBS) algorithms are used for surface definition and redistribution. The built in sculptured geometry definition with desired distribution of points, automatic Bezier curve/surface generation for interior boundaries/surfaces, and surface redistribution is based on NURBS. Weighted Lagrance/Hermite transfinite interpolation methods, interactive geometry/grid manipulation modules, and on-line graphical visualization of the generation process are salient features of this system which result in a significant time savings for a given geometry/grid application.

TIGGERC: Turbomachinery Interactive Grid Generator for 2-D Grid Applications and Users Guide

NASA Technical Reports Server (NTRS)

Miller, David P.

1994-01-01

A two-dimensional multi-block grid generator has been developed for a new design and analysis system for studying multiple blade-row turbomachinery problems. TIGGERC is a mouse driven, interactive grid generation program which can be used to modify boundary coordinates and grid packing and generates surface grids using a hyperbolic tangent or algebraic distribution of grid points on the block boundaries. The interior points of each block grid are distributed using a transfinite interpolation approach. TIGGERC can generate a blocked axisymmetric H-grid, C-grid, I-grid or O-grid for studying turbomachinery flow problems. TIGGERC was developed for operation on Silicon Graphics workstations. Detailed discussion of the grid generation methodology, menu options, operational features and sample grid geometries are presented.

Formation of Virtual Organizations in Grids: A Game-Theoretic Approach

NASA Astrophysics Data System (ADS)

Carroll, Thomas E.; Grosu, Daniel

The execution of large scale grid applications requires the use of several computational resources owned by various Grid Service Providers (GSPs). GSPs must form Virtual Organizations (VOs) to be able to provide the composite resource to these applications. We consider grids as self-organizing systems composed of autonomous, self-interested GSPs that will organize themselves into VOs with every GSP having the objective of maximizing its profit. We formulate the resource composition among GSPs as a coalition formation problem and propose a game-theoretic framework based on cooperation structures to model it. Using this framework, we design a resource management system that supports the VO formation among GSPs in a grid computing system.

Time-Dependent Simulation of Incompressible Flow in a Turbopump Using Overset Grid Approach

NASA Technical Reports Server (NTRS)

Kiris, Cetin; Kwak, Dochan

2001-01-01

This paper reports the progress being made towards complete unsteady turbopump simulation capability by using overset grid systems. A computational model of a turbo-pump impeller is used as a test case for the performance evaluation of the MPI, hybrid MPI/Open-MP, and MLP versions of the INS3D code. Relative motion of the grid system for rotor-stator interaction was obtained by employing overset grid techniques. Unsteady computations for a turbo-pump, which contains 114 zones with 34.3 Million grid points, are performed on Origin 2000 systems at NASA Ames Research Center. The approach taken for these simulations, and the performance of the parallel versions of the code are presented.

Grid-based precision aim system and method for disrupting suspect objects

DOEpatents

Gladwell, Thomas Scott; Garretson, Justin; Hobart, Clinton G.; Monda, Mark J.

2014-06-10

A system and method for disrupting at least one component of a suspect object is provided. The system has a source for passing radiation through the suspect object, a grid board positionable adjacent the suspect object (the grid board having a plurality of grid areas, the radiation from the source passing through the grid board), a screen for receiving the radiation passing through the suspect object and generating at least one image, a weapon for deploying a discharge, and a targeting unit for displaying the image of the suspect object and aiming the weapon according to a disruption point on the displayed image and deploying the discharge into the suspect object to disable the suspect object.

Research on control strategy based on fuzzy PR for grid-connected inverter

NASA Astrophysics Data System (ADS)

Zhang, Qian; Guan, Weiguo; Miao, Wen

2018-04-01

In the traditional PI controller, there is static error in tracking ac signals. To solve the problem, the control strategy of a fuzzy PR and the grid voltage feed-forward is proposed. The fuzzy PR controller is to eliminate the static error of the system. It also adjusts parameters of PR controller in real time, which avoids the defect of fixed parameter fixed. The grid voltage feed-forward control can ensure the quality of current and improve the system's anti-interference ability when the grid voltage is distorted. Finally, the simulation results show that the system can output grid current with good quality and also has good dynamic and steady state performance.

Glossary of AWS Acrinabs. Acronyms, Initialisms, and Abbreviations Commonly Used in Air Weather Service

DTIC Science & Technology

1991-01-01

Foundation FYDP ......... Five Year Defense Plan FSI ............ Fog Stability Index 17 G G ................ gravity, giga- GISM ......... Gridded ...Global Circulation Model GOES-TAP GOES imagery processing & dissemination system GCS .......... grid course GOFS ........ Global Ocean Flux Study GD...Analysis Support System Complex Systems GRID .......... Global Resource Information Data -Base GEMAG ..... geomagnetic GRIST..... grazing-incidence solar

Unlocking the potential of the smart grid

NASA Astrophysics Data System (ADS)

Konopko, Joanna

2015-12-01

The smart grid refers to describe a next-generation electrical power system that is typified by the increased use of Information and Communication Technologies (ICT) in the whole delivery electrical energy process. The generation, delivery and consumption energy, all the steps for power transmission and distribution make the smart grid a complex system. The question is if the amount, diversity, and uses of such data put the smart grid in the category of Big Data applications, followed by the natural question of what is the true value of such data. In this paper an initial answer to this question is provided, the current state of data generation of the Polish grid is analyzed, and a future realistic scenario is illustrated. The analysis shows that the amount of data generated in smart grid is comparable to some of Big Data system examples.

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

NASA Astrophysics Data System (ADS)

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.

Long-pulse power-supply system for EAST neutral-beam injectors

NASA Astrophysics Data System (ADS)

Liu, Zhimin; Jiang, Caichao; Pan, Junjun; Liu, Sheng; Xu, Yongjian; Chen, Shiyong; Hu, Chundong; NBI Team

2017-05-01

The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences): one for the neutral-beam test stand and two for the EAST neutral-beam injectors (NBI-1 and NBI-2, respectively). Each power supply system consists of two low voltage and high current DC power supplies for plasma generation of the ion source, and two high voltage and high current DC power supplies for the accelerator grid system. The operation range of the NB power supply is about 80 percent of the design value, which is the safe and stable operation range. At the neutral-beam test stand, a hydrogen ion beam with a beam pulse of 150 s, beam power of 1.5 MW and beam energy of 50 keV was achieved during the long-pulse testing experiments. The result shows that the power-supply system meets the requirements of the EAST-NBIs fully and lays a basis for achieving plasma heating.

Materials for suspension (semi-solid) electrodes for energy and water technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatzell, Kelsey B.; Boota, Muhammad; Gogotsi, Yury

2015-01-01

Suspension or semi-solid electrodes have recently gained increased attention for large-scale applications such as grid energy storage, capacitive water deionization, and wastewater treatment. A suspension electrode is a multiphase material system comprised of an active (charge storing) material suspended in ionic solution (electrolyte). Gravimetrically, the electrolyte is the majority component and aids in physical transport of the active material. For the first time, this principle enables, scalability of electrochemical energy storage devices (supercapacitors and batteries) previously limited to small and medium scale applications. This critical review describes the ongoing material challenges encompassing suspension-based systems. The research described here combines classicalmore » aspects of electrochemistry, colloidal science, material science, fluid mechanics, and rheology to describe ion and charge percolation, adsorption of ions, and redox charge storage processes in suspension electrodes. Our review summarizes the growing inventory of material systems, methods and practices used to characterize suspension electrodes, and describes universal material system properties (rheological, electrical, and electrochemical) that are pivotal in the design of high performing systems. We include a discussion of the primary challenges and future research directions.« less

Developing Use Cases for Evaluation of ADMS Applications to Accelerate Technology Adoption: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veda, Santosh; Wu, Hongyu; Martin, Maurice

Grid modernization for the distribution systems comprise of the ability to effectively monitor and manage unplanned events while ensuring reliable operations. Integration of Distributed Energy Resources (DERs) and proliferation of autonomous smart controllers like microgrids and smart inverters in the distribution networks challenge the status quo of distribution system operations. Advanced Distribution Management System (ADMS) technologies are being increasingly deployed to manage the complexities of operating distribution systems. The ability to evaluate the ADMS applications in specific utility environments and for future scenarios will accelerate wider adoption of the ADMS and will lower the risks and costs of their implementation.more » This paper addresses the first step - identify and define the use cases for evaluating these applications. The applications that are selected for this discussion include Volt-VAr Optimization (VVO), Fault Location Isolation and Service Restoration (FLISR), Online Power Flow (OLPF)/Distribution System State Estimation (DSSE) and Market Participation. A technical description and general operational requirements for each of these applications is presented. The test scenarios that are most relevant to the utility challenges are also addressed.« less

Integrated Devices and Systems | Grid Modernization | NREL

Science.gov Websites

storage models Microgrids Microgrids Grid Simulation and Power Hardware-in-the-Loop Grid simulation and power hardware-in-the-loop Grid Standards and Codes Standards and codes Contact Barry Mather, Ph.D

75 FR 63462 - Smart Grid Interoperability Standards; Notice of Docket Designation for Smart Grid...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-15

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. RM11-2-000] Smart Grid Interoperability Standards; Notice of Docket Designation for Smart Grid Interoperability Standards October 7, 2010... directs the development of a framework to achieve interoperability of smart grid devices and systems...

A Roadmap for caGrid, an Enterprise Grid Architecture for Biomedical Research

PubMed Central

Saltz, Joel; Hastings, Shannon; Langella, Stephen; Oster, Scott; Kurc, Tahsin; Payne, Philip; Ferreira, Renato; Plale, Beth; Goble, Carole; Ervin, David; Sharma, Ashish; Pan, Tony; Permar, Justin; Brezany, Peter; Siebenlist, Frank; Madduri, Ravi; Foster, Ian; Shanbhag, Krishnakant; Mead, Charlie; Hong, Neil Chue

2012-01-01

caGrid is a middleware system which combines the Grid computing, the service oriented architecture, and the model driven architecture paradigms to support development of interoperable data and analytical resources and federation of such resources in a Grid environment. The functionality provided by caGrid is an essential and integral component of the cancer Biomedical Informatics Grid (caBIG™) program. This program is established by the National Cancer Institute as a nationwide effort to develop enabling informatics technologies for collaborative, multi-institutional biomedical research with the overarching goal of accelerating translational cancer research. Although the main application domain for caGrid is cancer research, the infrastructure provides a generic framework that can be employed in other biomedical research and healthcare domains. The development of caGrid is an ongoing effort, adding new functionality and improvements based on feedback and use cases from the community. This paper provides an overview of potential future architecture and tooling directions and areas of improvement for caGrid and caGrid-like systems. This summary is based on discussions at a roadmap workshop held in February with participants from biomedical research, Grid computing, and high performance computing communities. PMID:18560123

A roadmap for caGrid, an enterprise Grid architecture for biomedical research.

PubMed

Saltz, Joel; Hastings, Shannon; Langella, Stephen; Oster, Scott; Kurc, Tahsin; Payne, Philip; Ferreira, Renato; Plale, Beth; Goble, Carole; Ervin, David; Sharma, Ashish; Pan, Tony; Permar, Justin; Brezany, Peter; Siebenlist, Frank; Madduri, Ravi; Foster, Ian; Shanbhag, Krishnakant; Mead, Charlie; Chue Hong, Neil

2008-01-01

caGrid is a middleware system which combines the Grid computing, the service oriented architecture, and the model driven architecture paradigms to support development of interoperable data and analytical resources and federation of such resources in a Grid environment. The functionality provided by caGrid is an essential and integral component of the cancer Biomedical Informatics Grid (caBIG) program. This program is established by the National Cancer Institute as a nationwide effort to develop enabling informatics technologies for collaborative, multi-institutional biomedical research with the overarching goal of accelerating translational cancer research. Although the main application domain for caGrid is cancer research, the infrastructure provides a generic framework that can be employed in other biomedical research and healthcare domains. The development of caGrid is an ongoing effort, adding new functionality and improvements based on feedback and use cases from the community. This paper provides an overview of potential future architecture and tooling directions and areas of improvement for caGrid and caGrid-like systems. This summary is based on discussions at a roadmap workshop held in February with participants from biomedical research, Grid computing, and high performance computing communities.

MIDG-Emerging grid technologies for multi-site preclinical molecular imaging research communities.

PubMed

Lee, Jasper; Documet, Jorge; Liu, Brent; Park, Ryan; Tank, Archana; Huang, H K

2011-03-01

Molecular imaging is the visualization and identification of specific molecules in anatomy for insight into metabolic pathways, tissue consistency, and tracing of solute transport mechanisms. This paper presents the Molecular Imaging Data Grid (MIDG) which utilizes emerging grid technologies in preclinical molecular imaging to facilitate data sharing and discovery between preclinical molecular imaging facilities and their collaborating investigator institutions to expedite translational sciences research. Grid-enabled archiving, management, and distribution of animal-model imaging datasets help preclinical investigators to monitor, access and share their imaging data remotely, and promote preclinical imaging facilities to share published imaging datasets as resources for new investigators. The system architecture of the Molecular Imaging Data Grid is described in a four layer diagram. A data model for preclinical molecular imaging datasets is also presented based on imaging modalities currently used in a molecular imaging center. The MIDG system components and connectivity are presented. And finally, the workflow steps for grid-based archiving, management, and retrieval of preclincial molecular imaging data are described. Initial performance tests of the Molecular Imaging Data Grid system have been conducted at the USC IPILab using dedicated VMware servers. System connectivity, evaluated datasets, and preliminary results are presented. The results show the system's feasibility, limitations, direction of future research. Translational and interdisciplinary research in medicine is increasingly interested in cellular and molecular biology activity at the preclinical levels, utilizing molecular imaging methods on animal models. The task of integrated archiving, management, and distribution of these preclinical molecular imaging datasets at preclinical molecular imaging facilities is challenging due to disparate imaging systems and multiple off-site investigators. A Molecular Imaging Data Grid design, implementation, and initial evaluation is presented to demonstrate the secure and novel data grid solution for sharing preclinical molecular imaging data across the wide-area-network (WAN).

A simple grid implementation with Berkeley Open Infrastructure for Network Computing using BLAST as a model

PubMed Central

Pinthong, Watthanai; Muangruen, Panya

2016-01-01

Development of high-throughput technologies, such as Next-generation sequencing, allows thousands of experiments to be performed simultaneously while reducing resource requirement. Consequently, a massive amount of experiment data is now rapidly generated. Nevertheless, the data are not readily usable or meaningful until they are further analysed and interpreted. Due to the size of the data, a high performance computer (HPC) is required for the analysis and interpretation. However, the HPC is expensive and difficult to access. Other means were developed to allow researchers to acquire the power of HPC without a need to purchase and maintain one such as cloud computing services and grid computing system. In this study, we implemented grid computing in a computer training center environment using Berkeley Open Infrastructure for Network Computing (BOINC) as a job distributor and data manager combining all desktop computers to virtualize the HPC. Fifty desktop computers were used for setting up a grid system during the off-hours. In order to test the performance of the grid system, we adapted the Basic Local Alignment Search Tools (BLAST) to the BOINC system. Sequencing results from Illumina platform were aligned to the human genome database by BLAST on the grid system. The result and processing time were compared to those from a single desktop computer and HPC. The estimated durations of BLAST analysis for 4 million sequence reads on a desktop PC, HPC and the grid system were 568, 24 and 5 days, respectively. Thus, the grid implementation of BLAST by BOINC is an efficient alternative to the HPC for sequence alignment. The grid implementation by BOINC also helped tap unused computing resources during the off-hours and could be easily modified for other available bioinformatics software. PMID:27547555

Power grid operation risk management: V2G deployment for sustainable development

NASA Astrophysics Data System (ADS)

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, it considers a two-stage model using the Benders Decomposition (BD). The numerical simulation demonstrate that the utilization of smart EV fleets in power grid systems would ensure a sustainable grid operation with lower carbon footprints, smoother integration of renewable sources, higher security, and lower power grid operation costs. The results, additionally, illustrate the effectiveness of the proposed MILP approach and its potentials as an optimization tool for sustainable operation of large scale electric power systems.

Circulation and multiple-scale variability in the Southern California Bight

NASA Astrophysics Data System (ADS)

Dong, Changming; Idica, Eileen Y.; McWilliams, James C.

2009-09-01

The oceanic circulation in the Southern California Bight (SCB) is influenced by the large-scale California Current offshore, tropical remote forcing through the coastal wave guide alongshore, and local atmospheric forcing. The region is characterized by local complexity in the topography and coastline. All these factors engender variability in the circulation on interannual, seasonal, and intraseasonal time scales. This study applies the Regional Oceanic Modeling System (ROMS) to the SCB circulation and its multiple-scale variability. The model is configured in three levels of nested grids with the parent grid covering the whole US West Coast. The first child grid covers a large southern domain, and the third grid zooms in on the SCB region. The three horizontal grid resolutions are 20 km, 6.7 km, and 1 km, respectively. The external forcings are momentum, heat, and freshwater flux at the surface and adaptive nudging to gyre-scale SODA reanalysis fields at the boundaries. The momentum flux is from a three-hourly reanalysis mesoscale MM5 wind with a 6 km resolution for the finest grid in the SCB. The oceanic model starts in an equilibrium state from a multiple-year cyclical climatology run, and then it is integrated from years 1996 through 2003. In this paper, the 8-year simulation at the 1 km resolution is analyzed and assessed against extensive observational data: High-Frequency (HF) radar data, current meters, Acoustic Doppler Current Profilers (ADCP) data, hydrographic measurements, tide gauges, drifters, altimeters, and radiometers. The simulation shows that the domain-scale surface circulation in the SCB is characterized by the Southern California Cyclonic Gyre, comprised of the offshore equatorward California Current System and the onshore poleward Southern California Countercurrent. The simulation also exhibits three subdomain-scale, persistent ( i.e., standing), cyclonic eddies related to the local topography and wind forcing: the Santa Barbara Channel Eddy, the Central-SCB Eddy, and the Catalina-Clemente Eddy. Comparisons with observational data reveal that ROMS reproduces a realistic mean state of the SCB oceanic circulation, as well as its interannual (mainly as a local manifestation of an ENSO event), seasonal, and intraseasonal (eddy-scale) variations. We find high correlations of the wind curl with both the alongshore pressure gradient (APG) and the eddy kinetic energy level in their variations on time scales of seasons and longer. The geostrophic currents are much stronger than the wind-driven Ekman flows at the surface. The model exhibits intrinsic eddy variability with strong topographically related heterogeneity, westward-propagating Rossby waves, and poleward-propagating coastally-trapped waves (albeit with smaller amplitude than observed due to missing high-frequency variations in the southern boundary conditions).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Happenny, Sean F.

The United States’ power infrastructure is aging, underfunded, and vulnerable to cyber attack. Emerging smart grid technologies may take some of the burden off of existing systems and make the grid as a whole more efficient, reliable, and secure. The Pacific Northwest National Laboratory (PNNL) is funding research into several aspects of smart grid technology and grid security, creating a software simulation tool that will allow researchers to test power distribution networks utilizing different smart grid technologies to determine how the grid and these technologies react under different circumstances. Demonstrating security in embedded systems is another research area PNNL ismore » tackling. Many of the systems controlling the U.S. critical infrastructure, such as the power grid, lack integrated security and the networks protecting them are becoming easier to breach. Providing a virtual power substation network to each student team at the National Collegiate Cyber Defense Competition, thereby supporting the education of future cyber security professionals, is another way PNNL is helping to strengthen the security of the nation’s power infrastructure.« less

Advanced Grid Simulator for Multi-Megawatt Power Converter Testing and Certification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koralewicz, Przemyslaw; Gevorgian, Vahan; Wallen, Robb

2017-02-16

Grid integration testing of inverter-coupled renewable energy technologies is an essential step in the qualification of renewable energy and energy storage systems to ensure the stability of the power system. New types of devices must be thoroughly tested and validated for compliance with relevant grid codes and interconnection requirements. For this purpose, highly specialized custom-made testing equipment is needed to emulate various types of realistic grid conditions that are required by certification bodies or for research purposes. For testing multi-megawatt converters, a high power grid simulator capable of creating controlled grid conditions and meeting both power quality and dynamic characteristicsmore » is needed. This paper describes the new grid simulator concept based on ABB's medium voltage ACS6000 drive technology that utilizes advanced modulation and control techniques to create an unique testing platform for various multi-megawatt power converter systems. Its performance is demonstrated utilizing the test results obtained during commissioning activities at the National Renewable Energy Laboratory in Colorado, USA.« less

Resilience Metrics for the Electric Power System: A Performance-Based Approach.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vugrin, Eric D.; Castillo, Andrea R; Silva-Monroy, Cesar Augusto

Grid resilience is a concept related to a power system's ability to continue operating and delivering power even in the event that low probability, high-consequence disruptions such as hurricanes, earthquakes, and cyber-attacks occur. Grid resilience objectives focus on managing and, ideally, minimizing potential consequences that occur as a result of these disruptions. Currently, no formal grid resilience definitions, metrics, or analysis methods have been universally accepted. This document describes an effort to develop and describe grid resilience metrics and analysis methods. The metrics and methods described herein extend upon the Resilience Analysis Process (RAP) developed by Watson et al. formore » the 2015 Quadrennial Energy Review. The extension allows for both outputs from system models and for historical data to serve as the basis for creating grid resilience metrics and informing grid resilience planning and response decision-making. This document describes the grid resilience metrics and analysis methods. Demonstration of the metrics and methods is shown through a set of illustrative use cases.« less

High efficiency ion beam accelerator system

NASA Technical Reports Server (NTRS)

Aston, G.

1981-01-01

An ion accelerator system that successfully combines geometrical and electrostatic focusing principles is presented. This accelerator system uses thin, concave, multiple-hole, closely spaced graphite screen and focusing grids which are coupled to single slot accelerator and decelerator grids to provide high ion extraction efficiency and good focusing. Tests with the system showed a substantial improvement in ion beam current density and collimation as compared with a Pierce electrode configuration. Durability of the thin graphite screen and focusing grids has been proven, and tests are being performed to determine the minimum screen and focusing grid spacing and thickness required to extract the maximum reliable beam current density. Compared with present neutral beam injector accelerator systems, this one has more efficient ion extraction, easier grid alignment, easier fabrication, a less cumbersome design, and the capacity to be constructed in a modular fashion. Conceptual neutral beam injector designs using this modular approach have electrostatic beam deflection plates downstream of each module.

Integrating Variable Renewable Energy - Russia

DOE Office of Scientific and Technical Information (OSTI.GOV)

To foster sustainable, low-emission development, many countries are establishing ambitious renewable energy targets for their electricity supply. Because solar and wind tend to be more variable and uncertain than conventional sources, meeting these targets will involve changes to power system planning and operations. Grid integration is the practice of developing efficient ways to deliver variable renewable energy (VRE) to the grid. Good integration methods maximize the cost-effectiveness of incorporating VRE into the power system while maintaining or increasing system stability and reliability. When considering grid integration, policy makers, regulators, and system operators consider a variety of issues, which can bemore » organized into four broad topics: New Renewable Energy Generation, New Transmission, Increased System Flexibility, Planning for a High RE Future. This is a Russian-language translation of Integrating Variable Renewable Energy into the Grid: Key Issues, Greening the Grid, originally published in English in May 2015.« less

Optimal configurations of spatial scale for grid cell firing under noise and uncertainty

PubMed Central

Towse, Benjamin W.; Barry, Caswell; Bush, Daniel; Burgess, Neil

2014-01-01

We examined the accuracy with which the location of an agent moving within an environment could be decoded from the simulated firing of systems of grid cells. Grid cells were modelled with Poisson spiking dynamics and organized into multiple ‘modules’ of cells, with firing patterns of similar spatial scale within modules and a wide range of spatial scales across modules. The number of grid cells per module, the spatial scaling factor between modules and the size of the environment were varied. Errors in decoded location can take two forms: small errors of precision and larger errors resulting from ambiguity in decoding periodic firing patterns. With enough cells per module (e.g. eight modules of 100 cells each) grid systems are highly robust to ambiguity errors, even over ranges much larger than the largest grid scale (e.g. over a 500 m range when the maximum grid scale is 264 cm). Results did not depend strongly on the precise organization of scales across modules (geometric, co-prime or random). However, independent spatial noise across modules, which would occur if modules receive independent spatial inputs and might increase with spatial uncertainty, dramatically degrades the performance of the grid system. This effect of spatial uncertainty can be mitigated by uniform expansion of grid scales. Thus, in the realistic regimes simulated here, the optimal overall scale for a grid system represents a trade-off between minimizing spatial uncertainty (requiring large scales) and maximizing precision (requiring small scales). Within this view, the temporary expansion of grid scales observed in novel environments may be an optimal response to increased spatial uncertainty induced by the unfamiliarity of the available spatial cues. PMID:24366144

Towards a Comprehensive Computational Simulation System for Turbomachinery

NASA Technical Reports Server (NTRS)

Shih, Ming-Hsin

1994-01-01

The objective of this work is to develop algorithms associated with a comprehensive computational simulation system for turbomachinery flow fields. This development is accomplished in a modular fashion. These modules includes grid generation, visualization, network, simulation, toolbox, and flow modules. An interactive grid generation module is customized to facilitate the grid generation process associated with complicated turbomachinery configurations. With its user-friendly graphical user interface, the user may interactively manipulate the default settings to obtain a quality grid within a fraction of time that is usually required for building a grid about the same geometry with a general-purpose grid generation code. Non-Uniform Rational B-Spline formulations are utilized in the algorithm to maintain geometry fidelity while redistributing grid points on the solid surfaces. Bezier curve formulation is used to allow interactive construction of inner boundaries. It is also utilized to allow interactive point distribution. Cascade surfaces are transformed from three-dimensional surfaces of revolution into two-dimensional parametric planes for easy manipulation. Such a transformation allows these manipulated plane grids to be mapped to surfaces of revolution by any generatrix definition. A sophisticated visualization module is developed to al-low visualization for both grid and flow solution, steady or unsteady. A network module is built to allow data transferring in the heterogeneous environment. A flow module is integrated into this system, using an existing turbomachinery flow code. A simulation module is developed to combine the network, flow, and visualization module to achieve near real-time flow simulation about turbomachinery geometries. A toolbox module is developed to support the overall task. A batch version of the grid generation module is developed to allow portability and has been extended to allow dynamic grid generation for pitch changing turbomachinery configurations. Various applications with different characteristics are presented to demonstrate the success of this system.

Distributed hierarchical control architecture for integrating smart grid assets during normal and disrupted operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalsi, Karan; Fuller, Jason C.; Somani, Abhishek

Disclosed herein are representative embodiments of methods, apparatus, and systems for facilitating operation and control of a resource distribution system (such as a power grid). Among the disclosed embodiments is a distributed hierarchical control architecture (DHCA) that enables smart grid assets to effectively contribute to grid operations in a controllable manner, while helping to ensure system stability and equitably rewarding their contribution. Embodiments of the disclosed architecture can help unify the dispatch of these resources to provide both market-based and balancing services.

Computer Aided Grid Interface: An Interactive CFD Pre-Processor

NASA Technical Reports Server (NTRS)

Soni, Bharat K.

1997-01-01

NASA maintains an applications oriented computational fluid dynamics (CFD) efforts complementary to and in support of the aerodynamic-propulsion design and test activities. This is especially true at NASA/MSFC where the goal is to advance and optimize present and future liquid-fueled rocket engines. Numerical grid generation plays a significant role in the fluid flow simulations utilizing CFD. An overall goal of the current project was to develop a geometry-grid generation tool that will help engineers, scientists and CFD practitioners to analyze design problems involving complex geometries in a timely fashion. This goal is accomplished by developing the CAGI: Computer Aided Grid Interface system. The CAGI system is developed by integrating CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) geometric system output and/or Initial Graphics Exchange Specification (IGES) files (including all the NASA-IGES entities), geometry manipulations and generations associated with grid constructions, and robust grid generation methodologies. This report describes the development process of the CAGI system.

Computer Aided Grid Interface: An Interactive CFD Pre-Processor

NASA Technical Reports Server (NTRS)

Soni, Bharat K.

1996-01-01

NASA maintains an applications oriented computational fluid dynamics (CFD) efforts complementary to and in support of the aerodynamic-propulsion design and test activities. This is especially true at NASA/MSFC where the goal is to advance and optimize present and future liquid-fueled rocket engines. Numerical grid generation plays a significant role in the fluid flow simulations utilizing CFD. An overall goal of the current project was to develop a geometry-grid generation tool that will help engineers, scientists and CFD practitioners to analyze design problems involving complex geometries in a timely fashion. This goal is accomplished by developing the Computer Aided Grid Interface system (CAGI). The CAGI system is developed by integrating CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) geometric system output and / or Initial Graphics Exchange Specification (IGES) files (including all the NASA-IGES entities), geometry manipulations and generations associated with grid constructions, and robust grid generation methodologies. This report describes the development process of the CAGI system.

Cyber-Physical System Security of a Power Grid: State-of-the-Art

DOE PAGES

Sun, Chih -Che; Liu, Chen -Ching; Xie, Jing

2016-07-14

Here, as part of the smart grid development, more and more technologies are developed and deployed on the power grid to enhance the system reliability. A primary purpose of the smart grid is to significantly increase the capability of computer-based remote control and automation. As a result, the level of connectivity has become much higher, and cyber security also becomes a potential threat to the cyber-physical systems (CPSs). In this paper, a survey of the state-of-the-art is conducted on the cyber security of the power grid concerning issues of: the structure of CPSs in a smart grid; cyber vulnerability assessment;more » cyber protection systems; and testbeds of a CPS. At Washington State University (WSU), the Smart City Testbed (SCT) has been developed to provide a platform to test, analyze and validate defense mechanisms against potential cyber intrusions. A test case is provided in this paper to demonstrate how a testbed helps the study of cyber security and the anomaly detection system (ADS) for substations.« less

Cyber-Physical System Security of a Power Grid: State-of-the-Art

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Chih -Che; Liu, Chen -Ching; Xie, Jing

Here, as part of the smart grid development, more and more technologies are developed and deployed on the power grid to enhance the system reliability. A primary purpose of the smart grid is to significantly increase the capability of computer-based remote control and automation. As a result, the level of connectivity has become much higher, and cyber security also becomes a potential threat to the cyber-physical systems (CPSs). In this paper, a survey of the state-of-the-art is conducted on the cyber security of the power grid concerning issues of: the structure of CPSs in a smart grid; cyber vulnerability assessment;more » cyber protection systems; and testbeds of a CPS. At Washington State University (WSU), the Smart City Testbed (SCT) has been developed to provide a platform to test, analyze and validate defense mechanisms against potential cyber intrusions. A test case is provided in this paper to demonstrate how a testbed helps the study of cyber security and the anomaly detection system (ADS) for substations.« less

Duke Energy | Energy Systems Integration Facility | NREL

Science.gov Websites

Smart Inverters for Grid Stability NREL and Duke Energy are exploring ways that smart inverters can increase grid stability. Photo of two men looking at a large simulation of the electric grid Grid Voltage

Research on LLCL Filtering Grid - Connected inverter under the Control of PFI

NASA Astrophysics Data System (ADS)

Li, Ren-qing; Zong, Ke-yong; Wang, Yan-ping; Li, Yang; Zhang, Jing

2018-03-01

This passage puts forward a kind of LLCL inverter which is based on the proportional feedback integral(PFI) control so as so satisfy the request of the grid-current outputed by the renewable energy generation system. The passage builds the topological graph of grid-connected inverter and makes an analysis of principle of linear superposition aims to reveal the essence of the problem of steady-state error that exists in proportional integral control. We use LLCL filter and the method of passive damping to solve the problem of resonant peak. We make simulation of the grid system with the software named MATLAB/Simulink. The result shows that the grid current enters steady state quickly and in the same time, which has the identical phase and frequency of grid-voltage. The harmonic content in grid current satisfies the request of grid standard.

Method and apparatus for two-dimensional absolute optical encoding

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

2004-01-01

This invention presents a two-dimensional absolute optical encoder and a method for determining position of an object in accordance with information from the encoder. The encoder of the present invention comprises a scale having a pattern being predetermined to indicate an absolute location on the scale, means for illuminating the scale, means for forming an image of the pattern; and detector means for outputting signals derived from the portion of the image of the pattern which lies within a field of view of the detector means, the field of view defining an image reference coordinate system, and analyzing means, receiving the signals from the detector means, for determining the absolute location of the object. There are two types of scale patterns presented in this invention: grid type and starfield type.

A Security Architecture for Grid-enabling OGC Web Services

NASA Astrophysics Data System (ADS)

Angelini, Valerio; Petronzio, Luca

2010-05-01

In the proposed presentation we describe an architectural solution for enabling a secure access to Grids and possibly other large scale on-demand processing infrastructures through OGC (Open Geospatial Consortium) Web Services (OWS). This work has been carried out in the context of the security thread of the G-OWS Working Group. G-OWS (gLite enablement of OGC Web Services) is an international open initiative started in 2008 by the European CYCLOPS , GENESI-DR, and DORII Project Consortia in order to collect/coordinate experiences in the enablement of OWS's on top of the gLite Grid middleware. G-OWS investigates the problem of the development of Spatial Data and Information Infrastructures (SDI and SII) based on the Grid/Cloud capacity in order to enable Earth Science applications and tools. Concerning security issues, the integration of OWS compliant infrastructures and gLite Grids needs to address relevant challenges, due to their respective design principles. In fact OWS's are part of a Web based architecture that demands security aspects to other specifications, whereas the gLite middleware implements the Grid paradigm with a strong security model (the gLite Grid Security Infrastructure: GSI). In our work we propose a Security Architectural Framework allowing the seamless use of Grid-enabled OGC Web Services through the federation of existing security systems (mostly web based) with the gLite GSI. This is made possible mediating between different security realms, whose mutual trust is established in advance during the deployment of the system itself. Our architecture is composed of three different security tiers: the user's security system, a specific G-OWS security system, and the gLite Grid Security Infrastructure. Applying the separation-of-concerns principle, each of these tiers is responsible for controlling the access to a well-defined resource set, respectively: the user's organization resources, the geospatial resources and services, and the Grid resources. While the gLite middleware is tied to a consolidated security approach based on X.509 certificates, our system is able to support different kinds of user's security infrastructures. Our central component, the G-OWS Security Framework, is based on the OASIS WS-Trust specifications and on the OGC GeoRM architectural framework. This allows to satisfy advanced requirements such as the enforcement of specific geospatial policies and complex secure web service chained requests. The typical use case is represented by a scientist belonging to a given organization who issues a request to a G-OWS Grid-enabled Web Service. The system initially asks the user to authenticate to his/her organization's security system and, after verification of the user's security credentials, it translates the user's digital identity into a G-OWS identity. This identity is linked to a set of attributes describing the user's access rights to the G-OWS services and resources. Inside the G-OWS Security system, access restrictions are applied making use of the enhanced Geospatial capabilities specified by the OGC GeoXACML. If the required action needs to make use of the Grid environment the system checks if the user is entitled to access a Grid infrastructure. In that case his/her identity is translated to a temporary Grid security token using the Short Lived Credential Services (IGTF Standard). In our case, for the specific gLite Grid infrastructure, some information (VOMS Attributes) is plugged into the Grid Security Token to grant the access to the user's Virtual Organization Grid resources. The resulting token is used to submit the request to the Grid and also by the various gLite middleware elements to verify the user's grants. Basing on the presented framework, the G-OWS Security Working Group developed a prototype, enabling the execution of OGC Web Services on the EGEE Production Grid through the federation with a Shibboleth based security infrastructure. Future plans aim to integrate other Web authentication services such as OpenID, Kerberos and WS-Federation.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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.

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

NASA Astrophysics Data System (ADS)

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.

20 plus Years of Computational Fluid Dynamics for the Space Shuttle

NASA Technical Reports Server (NTRS)

Gomez, Reynaldo J., III

2011-01-01

This slide presentation reviews the use of computational fluid dynamics in performing analysis of the space shuttle with particular reference to the return to flight analysis and other shuttle problems. Slides show a comparison of pressure coefficient with the shuttle ascent configuration between the wind tunnel test and the computed values. the evolution of the grid system for the space shuttle launch vehicle (SSLv) from the early 80's to one in 2004, the grid configuration of the bipod ramp redesign from the original design to the current configuration, charts with the computations showing solid rocket booster surface pressures from wind tunnel data, calculated over two grid systems (i.e., the original 14 grid system, and the enhanced 113 grid system), and the computed flight orbiter wing loads are compared with strain gage data on STS-50 during flight. The loss of STS-107 initiated an unprecedented review of all external environments. The current SSLV grid system of 600+ grids, 1.8 Million surface points and 95+ million volume points is shown. The inflight entry analyses is shown, and the use of Overset CFD as a key part to many external tank redesign and debris assessments is discussed. The work that still remains to be accomplished for future shuttle flights is discussed.

Sputtering Holes with Ion Beamlets

NASA Technical Reports Server (NTRS)

Byers, D. C.; Banks, B. A.

1974-01-01

Ion beamlets of predetermined configurations are formed by shaped apertures in the screen grid of an ion thruster having a double grid accelerator system. A plate is placed downstream from the screen grid holes and attached to the accelerator grid. When the ion thruster is operated holes having the configuration of the beamlets formed by the screen grid are sputtered through the plate at the accelerator grid.

Electrically heated particulate filter diagnostic systems and methods

DOEpatents

Gonze, Eugene V [Pinckney, MI

2009-09-29

A system that diagnoses regeneration of an electrically heated particulate filter is provided. The system generally includes a grid module that diagnoses a fault of the grid based on at least one of a current signal and a voltage signal. A diagnostic module at least one of sets a fault status and generates a warning signal based on the fault of the grid.

University of Delaware Demonstrated at NREL Vehicle-to-Grid Characteristics

Science.gov Websites

University of Delaware Demonstrated at NREL Vehicle-to-Grid Characteristics of Electric Vehicles At the Energy Systems Integration Facility (ESIF), the University of Delaware demonstrated the vehicle-to-grid , featuring vehilce-to-grid integration capabilities enabling it to feed power back to the grid and

From the grid to the smart grid, topologically

NASA Astrophysics Data System (ADS)

Pagani, Giuliano Andrea; Aiello, Marco

2016-05-01

In its more visionary acceptation, the smart grid is a model of energy management in which the users are engaged in producing energy as well as consuming it, while having information systems fully aware of the energy demand-response of the network and of dynamically varying prices. A natural question is then: to make the smart grid a reality will the distribution grid have to be upgraded? We assume a positive answer to the question and we consider the lower layers of medium and low voltage to be the most affected by the change. In our previous work, we analyzed samples of the Dutch distribution grid (Pagani and Aiello, 2011) and we considered possible evolutions of these using synthetic topologies modeled after studies of complex systems in other technological domains (Pagani and Aiello, 2014). In this paper, we take an extra important step by defining a methodology for evolving any existing physical power grid to a good smart grid model, thus laying the foundations for a decision support system for utilities and governmental organizations. In doing so, we consider several possible evolution strategies and apply them to the Dutch distribution grid. We show how increasing connectivity is beneficial in realizing more efficient and reliable networks. Our proposal is topological in nature, enhanced with economic considerations of the costs of such evolutions in terms of cabling expenses and economic benefits of evolving the grid.

Systems Engineering Building Advances Power Grid Research

ScienceCinema

Virden, Jud; Huang, Henry; Skare, Paul; Dagle, Jeff; Imhoff, Carl; Stoustrup, Jakob; Melton, Ron; Stiles, Dennis; Pratt, Rob

2018-01-16

Researchers and industry are now better equipped to tackle the nation’s most pressing energy challenges through PNNL’s new Systems Engineering Building – including challenges in grid modernization, buildings efficiency and renewable energy integration. This lab links real-time grid data, software platforms, specialized laboratories and advanced computing resources for the design and demonstration of new tools to modernize the grid and increase buildings energy efficiency.

Smart electric vehicle (EV) charging and grid integration apparatus and methods

DOEpatents

Gadh, Rajit; Mal, Siddhartha; Prabhu, Shivanand; Chu, Chi-Cheng; Sheikh, Omar; Chung, Ching-Yen; He, Lei; Xiao, Bingjun; Shi, Yiyu

2015-05-05

An expert system manages a power grid wherein charging stations are connected to the power grid, with electric vehicles connected to the charging stations, whereby the expert system selectively backfills power from connected electric vehicles to the power grid through a grid tie inverter (if present) within the charging stations. In more traditional usage, the expert system allows for electric vehicle charging, coupled with user preferences as to charge time, charge cost, and charging station capabilities, without exceeding the power grid capacity at any point. A robust yet accurate state of charge (SOC) calculation method is also presented, whereby initially an open circuit voltage (OCV) based on sampled battery voltages and currents is calculated, and then the SOC is obtained based on a mapping between a previously measured reference OCV (ROCV) and SOC. The OCV-SOC calculation method accommodates likely any battery type with any current profile.

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

NASA Astrophysics Data System (ADS)

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.

Enhanced Product Generation at NASA Data Centers Through Grid Technology

NASA Technical Reports Server (NTRS)

Barkstrom, Bruce R.; Hinke, Thomas H.; Gavali, Shradha; Seufzer, William J.

2003-01-01

This paper describes how grid technology can support the ability of NASA data centers to provide customized data products. A combination of grid technology and commodity processors are proposed to provide the bandwidth necessary to perform customized processing of data, with customized data subsetting providing the initial example. This customized subsetting engine can be used to support a new type of subsetting, called phenomena-based subsetting, where data is subsetted based on its association with some phenomena, such as mesoscale convective systems or hurricanes. This concept is expanded to allow the phenomena to be detected in one type of data, with the subsetting requirements transmitted to the subsetting engine to subset a different type of data. The subsetting requirements are generated by a data mining system and transmitted to the subsetter in the form of an XML feature index that describes the spatial and temporal extent of the phenomena. For this work, a grid-based mining system called the Grid Miner is used to identify the phenomena and generate the feature index. This paper discusses the value of grid technology in facilitating the development of a high performance customized product processing and the coupling of a grid mining system to support phenomena-based subsetting.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Jay Tillay

For three years, Sandia National Laboratories, Georgia Institute of Technology, and University of Illinois at Urbana-Champaign investigated a smart grid vision in which renewable-centric Virtual Power Plants (VPPs) provided ancillary services with interoperable distributed energy resources (DER). This team researched, designed, built, and evaluated real-time VPP designs incorporating DER forecasting, stochastic optimization, controls, and cyber security to construct a system capable of delivering reliable ancillary services, which have been traditionally provided by large power plants or other dedicated equipment. VPPs have become possible through an evolving landscape of state and national interconnection standards, which now require DER to include grid-supportmore » functionality and communications capabilities. This makes it possible for third party aggregators to provide a range of critical grid services such as voltage regulation, frequency regulation, and contingency reserves to grid operators. This paradigm (a) enables renewable energy, demand response, and energy storage to participate in grid operations and provide grid services, (b) improves grid reliability by providing additional operating reserves for utilities, independent system operators (ISOs), and regional transmission organization (RTOs), and (c) removes renewable energy high-penetration barriers by providing services with photovoltaics and wind resources that traditionally were the jobs of thermal generators. Therefore, it is believed VPP deployment will have far-reaching positive consequences for grid operations and may provide a robust pathway to high penetrations of renewables on US power systems. In this report, we design VPPs to provide a range of grid-support services and demonstrate one VPP which simultaneously provides bulk-system energy and ancillary reserves.« less

Research on the comparison of extension mechanism of cellular automaton based on hexagon grid and rectangular grid

NASA Astrophysics Data System (ADS)

Zhai, Xiaofang; Zhu, Xinyan; Xiao, Zhifeng; Weng, Jie

2009-10-01

Historically, cellular automata (CA) is a discrete dynamical mathematical structure defined on spatial grid. Research on cellular automata system (CAS) has focused on rule sets and initial condition and has not discussed its adjacency. Thus, the main focus of our study is the effect of adjacency on CA behavior. This paper is to compare rectangular grids with hexagonal grids on their characteristics, strengths and weaknesses. They have great influence on modeling effects and other applications including the role of nearest neighborhood in experimental design. Our researches present that rectangular and hexagonal grids have different characteristics. They are adapted to distinct aspects, and the regular rectangular or square grid is used more often than the hexagonal grid. But their relative merits have not been widely discussed. The rectangular grid is generally preferred because of its symmetry, especially in orthogonal co-ordinate system and the frequent use of raster from Geographic Information System (GIS). However, in terms of complex terrain, uncertain and multidirectional region, we have preferred hexagonal grids and methods to facilitate and simplify the problem. Hexagonal grids can overcome directional warp and have some unique characteristics. For example, hexagonal grids have a simpler and more symmetric nearest neighborhood, which avoids the ambiguities of the rectangular grids. Movement paths or connectivity, the most compact arrangement of pixels, make hexagonal appear great dominance in the process of modeling and analysis. The selection of an appropriate grid should be based on the requirements and objectives of the application. We use rectangular and hexagonal grids respectively for developing city model. At the same time we make use of remote sensing images and acquire 2002 and 2005 land state of Wuhan. On the base of city land state in 2002, we make use of CA to simulate reasonable form of city in 2005. Hereby, these results provide a proof of concept for hexagonal which has great dominance.

Absolute Geostrophic Velocity Inverted from World Ocean Atlas 2013 (WOAV13) with the P-Vector Method

DTIC Science & Technology

2015-11-01

The WOAV13 dataset comprises 3D global gridded climatological fields of absolute geostrophic velocity inverted...from World Ocean Atlas-2013 (WOA13) temperature and salinity fields using the P-vector method. It provides a climatological velocity field that is... climatology Dataset Identifier: gov.noaa.nodc:0121576 Creator: NOAP Lab, Department of Oceanography, Naval Postgraduate School, Monterey, CA Title

Transformation of two and three-dimensional regions by elliptic systems

NASA Technical Reports Server (NTRS)

Mastin, C. Wayne

1994-01-01

Several reports are attached to this document which contain the results of our research at the end of this contract period. Three of the reports deal with our work on generating surface grids. One is a preprint of a paper which will appear in the journal Applied Mathematics and Computation. Another is the abstract from a dissertation which has been prepared by Ahmed Khamayseh, a graduate student who has been supported by this grant for the last two years. The last report on surface grids is the extended abstract of a paper to be presented at the 14th IMACS World Congress in July. This report contains results on conformal mappings of surfaces, which are closely related to elliptic methods for surface grid generation. A preliminary report is included on new methods for dealing with block interfaces in multiblock grid systems. The development work is complete and the methods will eventually be incorporated into the National Grid Project (NGP) grid generation code. Thus, the attached report contains only a simple grid system which was used to test the algorithms to prove that the concepts are sound. These developments will greatly aid grid control when using elliptic systems and prevent unwanted grid movement. The last report is a brief summary of some timings that were obtained when the multiblock grid generation code was run on the Intel IPSC/860 hypercube. Since most of the data in a grid code is local to a particular block, only a small fraction of the total data must be passed between processors. The data is also distributed among the processors so that the total size of the grid can be increase along with the number of processors. This work is only in a preliminary stage. However, one of the ERC graduate students has taken an interest in the project and is presently extending these results as a part of his master's thesis.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov Websites

school. Andreas Schmitt spent hours this summer estimating grid voltage-under conditions when minimal Jiang of the State Grid Energy Research Institute in Beijing, China, to produce a review article that . The article, "Grid-Level Application of Electrical Energy Storage: Example Use Cases in the

Energy Systems Integration: Demonstrating the Grid Benefits of Connected Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Overview fact sheet about the Electric Power Research Institute (EPRI) and the University of Delaware Integrated Network Testbed for Energy Grid Research and Technology Experimentation (INTEGRATE) project at the Energy Systems Integration Facility. INTEGRATE is part of the U.S. Department of Energy's Grid Modernization Initiative.

Nuclear-renewable hybrid energy systems: Opportunities, interconnections, and needs

DOE PAGES

Ruth, Mark F.; Zinaman, Owen R.; Antkowiak, Mark; ...

2013-12-20

As the U.S. energy system evolves, the amount of electricity from variable-generation sources is likely to increase, which could result in additional times when electricity demand is lower than available production. Therefore, purveyors of technologies that traditionally have provided base-load electricity—such as nuclear power plants—can explore new operating procedures to deal with the associated market signals. Concurrently, innovations in nuclear reactor design coupled with sophisticated control systems now allow for more complex apportionment of heat within an integrated system such as one linked to energy-intensive chemical processes. Our paper explores one opportunity – nuclear-renewable hybrid energy systems. These are definedmore » as integrated facilities comprised of nuclear reactors, renewable energy generation, and industrial processes that can simultaneously address the need for grid flexibility, greenhouse gas emission reductions, and optimal use of investment capital. Six aspects of interaction (interconnections) between elements of nuclear-renewable hybrid energy systems are identified: Thermal, electrical, chemical, hydrogen, mechanical, and information. In addition, system-level aspects affect selection, design, and operation of this hybrid system type. Throughout the paper, gaps and research needs are identified to promote further exploration of the topic.« less

Spherical transceivers for ultrafast optical wireless communications

NASA Astrophysics Data System (ADS)

Jin, Xian; Hristovski, Blago A.; Collier, Christopher M.; Geoffroy-Gagnon, Simon; Born, Brandon; Holzman, Jonathan F.

2016-02-01

Optical wireless communications (OWC) offers the potential for high-speed and mobile operation in indoor networks. Such OWC systems often employ a fixed transmitter grid and mobile transceivers, with the mobile transceivers carrying out bi-directional communication via active downlinks (ideally with high-speed signal detection) and passive uplinks (ideally with broad angular retroreflection and high-speed modulation). It can be challenging to integrate all of these bidirectional communication capabilities within the mobile transceivers, however, as there is a simultaneous desire for compact packaging. With this in mind, the work presented here introduces a new form of transceiver for bi-directional OWC systems. The transceiver incorporates radial photoconductive switches (for high-speed signal detection) and a spherical retro-modulator (for broad angular retroreflection and high-speed all-optical modulation). All-optical retromodulation are investigated by way of theoretical models and experimental testing, for spherical retro-modulators comprised of three glasses, N-BK7, N-LASF9, and S-LAH79, having differing levels of refraction and nonlinearity. It is found that the spherical retro-modulator comprised of S-LAH79, with a refractive index of n ≍ 2 and a Kerr nonlinear index of n2 ≍ (1.8 ± 0.1) × 10-15 cm2/W, yields both broad angular retroreflection (over a solid angle of 2π steradians) and ultrafast modulation (over a duration of 120 fs). Such transceivers can become important elements for all-optical implementations in future bi-directional OWC systems.

Research and Deployment a Hospital Open Software Platform for e-Health on the Grid System at VAST/IAMI

NASA Astrophysics Data System (ADS)

van Tuyet, Dao; Tuan, Ngo Anh; van Lang, Tran

Grid computing has been an increasing topic in recent years. It attracts the attention of many scientists from many fields. As a result, many Grid systems have been built for serving people's demands. At present, many tools for developing the Grid systems such as Globus, gLite, Unicore still developed incessantly. Especially, gLite - the Grid Middleware - was developed by the Europe Community scientific in recent years. Constant growth of Grid technology opened the way for new opportunities in term of information and data exchange in a secure and collaborative context. These new opportunities can be exploited to offer physicians new telemedicine services in order to improve their collaborative capacities. Our platform gives physicians an easy method to use telemedicine environment to manage and share patient's information (such as electronic medical record, images formatted DICOM) between remote locations. This paper presents the Grid Infrastructure based on gLite; some main components of gLite; the challenge scenario in which new applications can be developed to improve collaborative work between scientists; the process of deploying Hospital Open software Platform for E-health (HOPE) on the Grid.

Multi-agent grid system Agent-GRID with dynamic load balancing of cluster nodes

NASA Astrophysics Data System (ADS)

Satymbekov, M. N.; Pak, I. T.; Naizabayeva, L.; Nurzhanov, Ch. A.

2017-12-01

In this study the work presents the system designed for automated load balancing of the contributor by analysing the load of compute nodes and the subsequent migration of virtual machines from loaded nodes to less loaded ones. This system increases the performance of cluster nodes and helps in the timely processing of data. A grid system balances the work of cluster nodes the relevance of the system is the award of multi-agent balancing for the solution of such problems.

Maintaining a Cognitive Map in Darkness: The Need to Fuse Boundary Knowledge with Path Integration

PubMed Central

Cheung, Allen; Ball, David; Milford, Michael; Wyeth, Gordon; Wiles, Janet

2012-01-01

Spatial navigation requires the processing of complex, disparate and often ambiguous sensory data. The neurocomputations underpinning this vital ability remain poorly understood. Controversy remains as to whether multimodal sensory information must be combined into a unified representation, consistent with Tolman's “cognitive map”, or whether differential activation of independent navigation modules suffice to explain observed navigation behaviour. Here we demonstrate that key neural correlates of spatial navigation in darkness cannot be explained if the path integration system acted independently of boundary (landmark) information. In vivo recordings demonstrate that the rodent head direction (HD) system becomes unstable within three minutes without vision. In contrast, rodents maintain stable place fields and grid fields for over half an hour without vision. Using a simple HD error model, we show analytically that idiothetic path integration (iPI) alone cannot be used to maintain any stable place representation beyond two to three minutes. We then use a measure of place stability based on information theoretic principles to prove that featureless boundaries alone cannot be used to improve localization above chance level. Having shown that neither iPI nor boundaries alone are sufficient, we then address the question of whether their combination is sufficient and – we conjecture – necessary to maintain place stability for prolonged periods without vision. We addressed this question in simulations and robot experiments using a navigation model comprising of a particle filter and boundary map. The model replicates published experimental results on place field and grid field stability without vision, and makes testable predictions including place field splitting and grid field rescaling if the true arena geometry differs from the acquired boundary map. We discuss our findings in light of current theories of animal navigation and neuronal computation, and elaborate on their implications and significance for the design, analysis and interpretation of experiments. PMID:22916006

Extending Climate Analytics-As to the Earth System Grid Federation

NASA Astrophysics Data System (ADS)

Tamkin, G.; Schnase, J. L.; Duffy, D.; McInerney, M.; Nadeau, D.; Li, J.; Strong, S.; Thompson, J. H.

2015-12-01

We are building three extensions to prior-funded work on climate analytics-as-a-service that will benefit the Earth System Grid Federation (ESGF) as it addresses the Big Data challenges of future climate research: (1) We are creating a cloud-based, high-performance Virtual Real-Time Analytics Testbed supporting a select set of climate variables from six major reanalysis data sets. This near real-time capability will enable advanced technologies like the Cloudera Impala-based Structured Query Language (SQL) query capabilities and Hadoop-based MapReduce analytics over native NetCDF files while providing a platform for community experimentation with emerging analytic technologies. (2) We are building a full-featured Reanalysis Ensemble Service comprising monthly means data from six reanalysis data sets. The service will provide a basic set of commonly used operations over the reanalysis collections. The operations will be made accessible through NASA's climate data analytics Web services and our client-side Climate Data Services (CDS) API. (3) We are establishing an Open Geospatial Consortium (OGC) WPS-compliant Web service interface to our climate data analytics service that will enable greater interoperability with next-generation ESGF capabilities. The CDS API will be extended to accommodate the new WPS Web service endpoints as well as ESGF's Web service endpoints. These activities address some of the most important technical challenges for server-side analytics and support the research community's requirements for improved interoperability and improved access to reanalysis data.

Development and Testing of the Glenn Research Center Visitor's Center Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) has developed, installed, and tested a 12 kW DC grid-tied photovoltaic (PV) power system at the GRC Visitor s Center. This system utilizes a unique ballast type roof mount for installing the photovoltaic panels on the roof of the Visitor s Center with no alterations or penetrations to the roof. The PV system has generated in excess of 15000 kWh since operation commenced in August 2008. The PV system is providing power to the GRC grid for use by all. Operation of the GRC Visitor s Center 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 provides 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 GRC Visitor s Center PV system, additional PV power system expansion at GRC is under consideration. The GRC Visitor s Center 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.

Preface: Workshop on Off-Grid Technology Systems

NASA Astrophysics Data System (ADS)

Alonso-Marroquin, Fernando

2017-06-01

Off-grid houses are dwellings that do not rely on water supply, sewer, or electrical power grid, and are able to operate independently of all public utility services. These houses are ideal for remote communities or population suffering natural or human-made disasters. Our aim is to develop compact and affordable off-grid technologies by integrating high-end nano-engineering with systems that imitates natural biological processes. The key areas of focus in the workshop were: solar energy harvesting using nanotechnology, wind energy harvesting from vertical-axis wind turbines, supercapacitors energy storage systems, treatment of greywater, and green roofs to achieve air comfort.

Evaluation of microfabricated deformable mirror systems

NASA Astrophysics Data System (ADS)

Cowan, William D.; Lee, Max K.; Bright, Victor M.; Welsh, Byron M.

1998-09-01

This paper presents recent result for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages, thus eliminating high voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203 micrometers 12 by 12 square grid. The overall array size is 2.4 mm square. The arrays were fabricated in the commercially available DARPA supported MUMPs surface micromachining foundry process. The cost per mirror array in this prototyping process is less than 200 dollars. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror which requires no digital to analog converters, further reducing the cost of adaptive optics system.

Non-isolated high gain DC-DC converter for smart grid- A review

NASA Astrophysics Data System (ADS)

Divya Navamani, J.; Vijayakumar, K.; Lavanya, A.; Mano Raj, A. Jason

2018-04-01

Smart grids are becoming the most interesting and promising alternative for an electric grid system. Power conditioning units and control over the distribution of power is the essential feature for the smart grid system. In this paper, we reviewed several non-isolated high gain topologies derived from boost converter for providing required voltage to the grid tie inverter from renewable energy sources. Steady state analysis of all the topologies is analyzed to compare the performance of the topologies. Simulation is carried out in nL5 simulator and the results are compared and validated with the theoretical results. This paper is a guide to the researchers to choose the best topology for the smart grid application.

Transformation of two and three-dimensional regions by elliptic systems

NASA Technical Reports Server (NTRS)

Mastin, C. Wayne

1991-01-01

A reliable linear system is presented for grid generation in 2-D and 3-D. The method is robust in the sense that convergence is guaranteed but is not as reliable as other nonlinear elliptic methods in generating nonfolding grids. The construction of nonfolding grids depends on having reasonable approximations of cell aspect ratios and an appropriate distribution of grid points on the boundary of the region. Some guidelines are included on approximating the aspect ratios, but little help is offered on setting up the boundary grid other than to say that in 2-D the boundary correspondence should be close to that generated by a conformal mapping. It is assumed that the functions which control the grid distribution depend only on the computational variables and not on the physical variables. Whether this is actually the case depends on how the grid is constructed. In a dynamic adaptive procedure where the grid is constructed in the process of solving a fluid flow problem, the grid is usually updated at fixed iteration counts using the current value of the control function. Since the control function is not being updated during the iteration of the grid equations, the grid construction is a linear procedure. However, in the case of a static adaptive procedure where a trial solution is computed and used to construct an adaptive grid, the control functions may be recomputed at every step of the grid iteration.

78 FR 22846 - Smart Grid Advisory Committee Meeting Cancellation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-17

... DEPARTMENT OF COMMERCE National Institute of Standards and Technology Smart Grid Advisory... Commerce. ACTION: Notice of meeting cancellation. SUMMARY: The meeting of the Smart Grid Advisory Committee... INFORMATION CONTACT: Mr. Cuong Nguyen, Smart Grid and Cyber-Physical Systems Program Office, National...

Multiscale model reduction for shale gas transport in poroelastic fractured media

NASA Astrophysics Data System (ADS)

Akkutlu, I. Yucel; Efendiev, Yalchin; Vasilyeva, Maria; Wang, Yuhe

2018-01-01

Inherently coupled flow and geomechanics processes in fractured shale media have implications for shale gas production. The system involves highly complex geo-textures comprised of a heterogeneous anisotropic fracture network spatially embedded in an ultra-tight matrix. In addition, nonlinearities due to viscous flow, diffusion, and desorption in the matrix and high velocity gas flow in the fractures complicates the transport. In this paper, we develop a multiscale model reduction approach to couple gas flow and geomechanics in fractured shale media. A Discrete Fracture Model (DFM) is used to treat the complex network of fractures on a fine grid. The coupled flow and geomechanics equations are solved using a fixed stress-splitting scheme by solving the pressure equation using a continuous Galerkin method and the displacement equation using an interior penalty discontinuous Galerkin method. We develop a coarse grid approximation and coupling using the Generalized Multiscale Finite Element Method (GMsFEM). GMsFEM constructs the multiscale basis functions in a systematic way to capture the fracture networks and their interactions with the shale matrix. Numerical results and an error analysis is provided showing that the proposed approach accurately captures the coupled process using a few multiscale basis functions, i.e. a small fraction of the degrees of freedom of the fine-scale problem.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Ning; Wang, Jianhui; Singh, Ravindra

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 amore » 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.« less

Purely Translational Realignment in Grid Cell Firing Patterns Following Nonmetric Context Change

PubMed Central

Marozzi, Elizabeth; Ginzberg, Lin Lin; Alenda, Andrea; Jeffery, Kate J.

2015-01-01

Grid cells in entorhinal and parahippocampal cortices contribute to a network, centered on the hippocampal place cell system, that constructs a representation of spatial context for use in navigation and memory. In doing so, they use metric cues such as the distance and direction of nearby boundaries to position and orient their firing field arrays (grids). The present study investigated whether they also use purely nonmetric “context” information such as color and odor of the environment. We found that, indeed, purely nonmetric cues—sufficiently salient to cause changes in place cell firing patterns—can regulate grid positioning; they do so independently of orientation, and thus interact with linear but not directional spatial inputs. Grid cells responded homogeneously to context changes. We suggest that the grid and place cell networks receive context information directly and also from each other; the information is used by place cells to compute the final decision of the spatial system about which context the animal is in, and by grid cells to help inform the system about where the animal is within it. PMID:26048956

Grid Stability Awareness System (GSAS) Final Scientific/Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feuerborn, Scott; Ma, Jian; Black, Clifton

The project team developed a software suite named Grid Stability Awareness System (GSAS) for power system near real-time stability monitoring and analysis based on synchrophasor measurement. The software suite consists of five analytical tools: an oscillation monitoring tool, a voltage stability monitoring tool, a transient instability monitoring tool, an angle difference monitoring tool, and an event detection tool. These tools have been integrated into one framework to provide power grid operators with both real-time or near real-time stability status of a power grid and historical information about system stability status. These tools are being considered for real-time use in themore » operation environment.« less

A Damping Grid Strapdown Inertial Navigation System Based on a Kalman Filter for Ships in Polar Regions.

PubMed

Huang, Weiquan; Fang, Tao; Luo, Li; Zhao, Lin; Che, Fengzhu

2017-07-03

The grid strapdown inertial navigation system (SINS) used in polar navigation also includes three kinds of periodic oscillation errors as common SINS are based on a geographic coordinate system. Aiming ships which have the external information to conduct a system reset regularly, suppressing the Schuler periodic oscillation is an effective way to enhance navigation accuracy. The Kalman filter based on the grid SINS error model which applies to the ship is established in this paper. The errors of grid-level attitude angles can be accurately estimated when the external velocity contains constant error, and then correcting the errors of the grid-level attitude angles through feedback correction can effectively dampen the Schuler periodic oscillation. The simulation results show that with the aid of external reference velocity, the proposed external level damping algorithm based on the Kalman filter can suppress the Schuler periodic oscillation effectively. Compared with the traditional external level damping algorithm based on the damping network, the algorithm proposed in this paper can reduce the overshoot errors when the state of grid SINS is switched from the non-damping state to the damping state, and this effectively improves the navigation accuracy of the system.

Hybrid AC-High Voltage DC Grid Stability and Controls

NASA Astrophysics Data System (ADS)

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 features.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov Websites

power grid modeling scenarios Study Shows Eastern U.S. Power Grid Can Support Upwards of 30% Wind and newly released Eastern Renewable Energy Integration Study (ERGIS) shows that the power grid of the -based study of four potential wind and PV futures and associated operational impacts in the Eastern

STABILIZED FEEDBACK AMPLIFIER

DOEpatents

Fishbine, H.L.; Sewell, C. Jr.

1957-08-01

Negative feedback amplifiers, and particularly a negative feedback circuit which is economical on amode power consumption, are described. Basically, the disclosed circuit comprises two tetrode tubes where the output of the first tube is capacitamce coupled to the grid of the second tube, which in turn has its plate coupled to the cathode of the first tube to form a degenerative feedback circuit. Operating potential for screen of the second tube is supplied by connecting the cathode resistor of the first tube to the screen, while the screen is by-passed to the cathode of its tube for the amplified frequencies. Also, the amplifier incorporates a circuit to stabilize the transconductance of the tubes by making the grid potential of each tube interdependent on anode currents of both lubes by voltage divider circuitry.

PULSE GENERATOR

DOEpatents

Roeschke, C.W.

1957-09-24

An improvement in pulse generators is described by which there are produced pulses of a duration from about 1 to 10 microseconds with a truly flat top and extremely rapid rise and fall. The pulses are produced by triggering from a separate input or by modifying the current to operate as a free-running pulse generator. In its broad aspect, the disclosed pulse generator comprises a first tube with an anode capacitor and grid circuit which controls the firing; a second tube series connected in the cathode circuit of the first tube such that discharge of the first tube places a voltage across it as the leading edge of the desired pulse; and an integrator circuit from the plate across the grid of the second tube to control the discharge time of the second tube, determining the pulse length.

Data privacy considerations in Intensive Care Grids.

PubMed

Luna, Jesus; Dikaiakos, Marios D; Kyprianou, Theodoros; Bilas, Angelos; Marazakis, Manolis

2008-01-01

Novel eHealth systems are being designed to provide a citizen-centered health system, however the even demanding need for computing and data resources has required the adoption of Grid technologies. In most of the cases, this novel Health Grid requires not only conveying patient's personal data through public networks, but also storing it into shared resources out of the hospital premises. These features introduce new security concerns, in particular related with privacy. In this paper we survey current legal and technological approaches that have been taken to protect a patient's personal data into eHealth systems, with a particular focus in Intensive Care Grids. However, thanks to a security analysis applied over the Intensive Care Grid system (ICGrid) we show that these security mechanisms are not enough to provide a comprehensive solution, mainly because the data-at-rest is still vulnerable to attacks coming from untrusted Storage Elements where an attacker may directly access them. To cope with these issues, we propose a new privacy-oriented protocol which uses a combination of encryption and fragmentation to improve data's assurance while keeping compatibility with current legislations and Health Grid security mechanisms.

Ion extraction capabilities of two-grid accelerator systems. M.S. Thesis

NASA Technical Reports Server (NTRS)

Rovang, D. C.; Wilbur, P. J.

1984-01-01

An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. This work resulted in a large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high. The apparatus developed for this study is also shown to be well suited measuring the electron backstreaming and electrical breakdown characteristics of two-grid accelerator systems.

Taming instabilities in power grid networks by decentralized control

NASA Astrophysics Data System (ADS)

Schäfer, B.; Grabow, C.; Auer, S.; Kurths, J.; Witthaut, D.; Timme, M.

2016-05-01

Renewables will soon dominate energy production in our electric power system. And yet, how to integrate renewable energy into the grid and the market is still a subject of major debate. Decentral Smart Grid Control (DSGC) was recently proposed as a robust and decentralized approach to balance supply and demand and to guarantee a grid operation that is both economically and dynamically feasible. Here, we analyze the impact of network topology by assessing the stability of essential network motifs using both linear stability analysis and basin volume for delay systems. Our results indicate that if frequency measurements are averaged over sufficiently large time intervals, DSGC enhances the stability of extended power grid systems. We further investigate whether DSGC supports centralized and/or decentralized power production and find it to be applicable to both. However, our results on cycle-like systems suggest that DSGC favors systems with decentralized production. Here, lower line capacities and lower averaging times are required compared to those with centralized production.

Optimal Wind Energy Integration in Large-Scale Electric Grids

NASA Astrophysics Data System (ADS)

Albaijat, Mohammad H.

The major concern in electric grid operation is operating under the most economical and reliable fashion to ensure affordability and continuity of electricity supply. This dissertation investigates the effects of such challenges, which affect electric grid reliability and economic operations. These challenges are: 1. Congestion of transmission lines, 2. Transmission lines expansion, 3. Large-scale wind energy integration, and 4. Phaser Measurement Units (PMUs) optimal placement for highest electric grid observability. Performing congestion analysis aids in evaluating the required increase of transmission line capacity in electric grids. However, it is necessary to evaluate expansion of transmission line capacity on methods to ensure optimal electric grid operation. Therefore, the expansion of transmission line capacity must enable grid operators to provide low-cost electricity while maintaining reliable operation of the electric grid. Because congestion affects the reliability of delivering power and increases its cost, the congestion analysis in electric grid networks is an important subject. Consequently, next-generation electric grids require novel methodologies for studying and managing congestion in electric grids. We suggest a novel method of long-term congestion management in large-scale electric grids. Owing to the complication and size of transmission line systems and the competitive nature of current grid operation, it is important for electric grid operators to determine how many transmission lines capacity to add. Traditional questions requiring answers are "Where" to add, "How much of transmission line capacity" to add, and "Which voltage level". Because of electric grid deregulation, transmission lines expansion is more complicated as it is now open to investors, whose main interest is to generate revenue, to build new transmission lines. Adding a new transmission capacity will help the system to relieve the transmission system congestion, create profit for investors for renting their transmission capacity, and cheaper electricity for end users. We propose a hybrid method based on a heuristic and deterministic method to attain new transmission lines additions and increase transmission capacity. Renewable energy resources (RES) have zero operating cost, which makes them very attractive for generation companies and market participants. In addition, RES have zero carbon emission, which helps relieve the concerns of environmental impacts of electric generation resources' carbon emission. RES are wind, solar, hydro, biomass, and geothermal. By 2030, the expectation is that more than 30% of electricity in the U.S. will come from RES. One major contributor of RES generation will be from wind energy resources (WES). Furthermore, WES will be an important component of the future generation portfolio. However, the nature of WES is that it experiences a high intermittency and volatility. Because of the great expectation of high WES penetration and the nature of such resources, researchers focus on studying the effects of such resources on the electric grid operation and its adequacy from different aspects. Additionally, current market operations of electric grids add another complication to consider while integrating RES (e.g., specifically WES). Mandates by market rules and long-term analysis of renewable penetration in large-scale electric grid are also the focus of researchers in recent years. We advocate a method for high-wind resources penetration study on large-scale electric grid operations. PMU is a geographical positioning system (GPS) based device, which provides immediate and precise measurements of voltage angle in a high-voltage transmission system. PMUs can update the status of a transmission line and related measurements (e.g., voltage magnitude and voltage phase angle) more frequently. Every second, a PMU can provide 30 samples of measurements compared to traditional systems (e.g., supervisory control and data acquisition [SCADA] system), which provides one sample of measurement every 2 to 5 seconds. Because PMUs provide more measurement data samples, PMU can improve electric grid reliability and observability. (Abstract shortened by UMI.)

Grid Modernization | NREL

Science.gov Websites

development to improve the nation's electrical grid infrastructure, making it more flexible, reliable Standard, IEEE 1547 Blue cover page of report with hexagon shapes over electric grid Basic Research Needs Controls Power Systems Design and Studies Security and Resilience Institutional Support NREL grid research

Multiple-block grid adaption for an airplane geometry

NASA Technical Reports Server (NTRS)

Abolhassani, Jamshid Samareh; Smith, Robert E.

1988-01-01

Grid-adaption methods are developed with the capability of moving grid points in accordance with several variables for a three-dimensional multiple-block grid system. These methods are algebraic, and they are implemented for the computation of high-speed flow over an airplane configuration.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babun, Leonardo; Aksu, Hidayet; Uluagac, A. Selcuk

The core vision of the smart grid concept is the realization of reliable two-­way communications between smart devices (e.g., IEDs, PLCs, PMUs). The benefits of the smart grid also come with tremendous security risks and new challenges in protecting the smart grid systems from cyber threats. Particularly, the use of untrusted counterfeit smart grid devices represents a real problem. Consequences of propagating false or malicious data, as well as stealing valuable user or smart grid state information from counterfeit devices are costly. Hence, early detection of counterfeit devices is critical for protecting smart grid’s components and users. To address thesemore » concerns, in this poster, we introduce our initial design of a configurable framework that utilize system call tracing, library interposition, and statistical techniques for monitoring and detection of counterfeit smart grid devices. In our framework, we consider six different counterfeit device scenarios with different smart grid devices and adversarial seZings. Our initial results on a realistic testbed utilizing actual smart-­grid GOOSE messages with IEC-­61850 communication protocol are very promising. Our framework is showing excellent rates on detection of smart grid counterfeit devices from impostors.« less

User Manual for Beta Version of TURBO-GRD: A Software System for Interactive Two-Dimensional Boundary/ Field Grid Generation, Modification, and Refinement

NASA Technical Reports Server (NTRS)

Choo, Yung K.; Slater, John W.; Henderson, Todd L.; Bidwell, Colin S.; Braun, Donald C.; Chung, Joongkee

1998-01-01

TURBO-GRD is a software system for interactive two-dimensional boundary/field grid generation. modification, and refinement. Its features allow users to explicitly control grid quality locally and globally. The grid control can be achieved interactively by using control points that the user picks and moves on the workstation monitor or by direct stretching and refining. The techniques used in the code are the control point form of algebraic grid generation, a damped cubic spline for edge meshing and parametric mapping between physical and computational domains. It also performs elliptic grid smoothing and free-form boundary control for boundary geometry manipulation. Internal block boundaries are constructed and shaped by using Bezier curve. Because TURBO-GRD is a highly interactive code, users can read in an initial solution, display its solution contour in the background of the grid and control net, and exercise grid modification using the solution contour as a guide. This process can be called an interactive solution-adaptive grid generation.

The three-dimensional Multi-Block Advanced Grid Generation System (3DMAGGS)

NASA Technical Reports Server (NTRS)

Alter, Stephen J.; Weilmuenster, Kenneth J.

1993-01-01

As the size and complexity of three dimensional volume grids increases, there is a growing need for fast and efficient 3D volumetric elliptic grid solvers. Present day solvers are limited by computational speed and do not have all the capabilities such as interior volume grid clustering control, viscous grid clustering at the wall of a configuration, truncation error limiters, and convergence optimization residing in one code. A new volume grid generator, 3DMAGGS (Three-Dimensional Multi-Block Advanced Grid Generation System), which is based on the 3DGRAPE code, has evolved to meet these needs. This is a manual for the usage of 3DMAGGS and contains five sections, including the motivations and usage, a GRIDGEN interface, a grid quality analysis tool, a sample case for verifying correct operation of the code, and a comparison to both 3DGRAPE and GRIDGEN3D. Since it was derived from 3DGRAPE, this technical memorandum should be used in conjunction with the 3DGRAPE manual (NASA TM-102224).

Critical Infrastructure Protection: EMP Impacts on the U.S. Electric Grid

NASA Astrophysics Data System (ADS)

Boston, Edwin J., Jr.

The purpose of this research is to identify the United States electric grid infrastructure systems vulnerabilities to electromagnetic pulse attacks and the cyber-based impacts of those vulnerabilities to the electric grid. Additionally, the research identifies multiple defensive strategies designed to harden the electric grid against electromagnetic pulse attack that include prevention, mitigation and recovery postures. Research results confirm the importance of the electric grid to the United States critical infrastructures system and that an electromagnetic pulse attack against the electric grid could result in electric grid degradation, critical infrastructure(s) damage and the potential for societal collapse. The conclusions of this research indicate that while an electromagnetic pulse attack against the United States electric grid could have catastrophic impacts on American society, there are currently many defensive strategies under consideration designed to prevent, mitigate and or recover from an electromagnetic pulse attack. However, additional research is essential to further identify future target hardening opportunities, efficient implementation strategies and funding resources.

RXIO: Design and implementation of high performance RDMA-capable GridFTP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Yuan; Yu, Weikuan; Vetter, Jeffrey S.

2011-12-21

For its low-latency, high bandwidth, and low CPU utilization, Remote Direct Memory Access (RDMA) has established itself as an effective data movement technology in many networking environments. However, the transport protocols of grid run-time systems, such as GridFTP in Globus, are not yet capable of utilizing RDMA. In this study, we examine the architecture of GridFTP for the feasibility of enabling RDMA. An RDMA-capable XIO (RXIO) framework is designed and implemented to extend its XIO system and match the characteristics of RDMA. Our experimental results demonstrate that RDMA can significantly improve the performance of GridFTP, reducing the latency by 32%more » and increasing the bandwidth by more than three times. In achieving such performance improvements, RDMA dramatically cuts down CPU utilization of GridFTP clients and servers. In conclusion, these results demonstrate that RXIO can effectively exploit the benefits of RDMA for GridFTP. It offers a good prototype to further leverage GridFTP on wide-area RDMA networks.« less

FUN3D and CFL3D Computations for the First High Lift Prediction Workshop

NASA Technical Reports Server (NTRS)

Park, Michael A.; Lee-Rausch, Elizabeth M.; Rumsey, Christopher L.

2011-01-01

Two Reynolds-averaged Navier-Stokes codes were used to compute flow over the NASA Trapezoidal Wing at high lift conditions for the 1st AIAA CFD High Lift Prediction Workshop, held in Chicago in June 2010. The unstructured-grid code FUN3D and the structured-grid code CFL3D were applied to several different grid systems. The effects of code, grid system, turbulence model, viscous term treatment, and brackets were studied. The SST model on this configuration predicted lower lift than the Spalart-Allmaras model at high angles of attack; the Spalart-Allmaras model agreed better with experiment. Neglecting viscous cross-derivative terms caused poorer prediction in the wing tip vortex region. Output-based grid adaptation was applied to the unstructured-grid solutions. The adapted grids better resolved wake structures and reduced flap flow separation, which was also observed in uniform grid refinement studies. Limitations of the adaptation method as well as areas for future improvement were identified.

The impact of the topology on cascading failures in a power grid model

NASA Astrophysics Data System (ADS)

Koç, Yakup; Warnier, Martijn; Mieghem, Piet Van; Kooij, Robert E.; Brazier, Frances M. T.

2014-05-01

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 assessed by purely topological approaches, that fail to capture the essence of electric power flow. This paper proposes a metric, the effective graph resistance, to relate the topology of a power grid to its robustness against cascading failures by deliberate attacks, while also taking the fundamental characteristics of the electric power grid into account such as power flow allocation according to Kirchhoff laws. Experimental verification on synthetic power systems shows that the proposed metric reflects the grid robustness accurately. The proposed metric is used to optimize a grid topology for a higher level of robustness. To demonstrate its applicability, the metric is applied on the IEEE 118 bus power system to improve its robustness against cascading failures.

Non-Pilot Protection of the HVDC Grid

NASA Astrophysics Data System (ADS)

Badrkhani Ajaei, Firouz

This thesis develops a non-pilot protection system for the next generation power transmission system, the High-Voltage Direct Current (HVDC) grid. The HVDC grid protection system is required to be (i) adequately fast to prevent damages and/or converter blocking and (ii) reliable to minimize the impacts of faults. This study is mainly focused on the Modular Multilevel Converter (MMC) -based HVDC grid since the MMC is considered as the building block of the future HVDC systems. The studies reported in this thesis include (i) developing an enhanced equivalent model of the MMC to enable accurate representation of its DC-side fault response, (ii) developing a realistic HVDC-AC test system that includes a five-terminal MMC-based HVDC grid embedded in a large interconnected AC network, (iii) investigating the transient response of the developed test system to AC-side and DC-side disturbances in order to determine the HVDC grid protection requirements, (iv) investigating the fault surge propagation in the HVDC grid to determine the impacts of the DC-side fault location on the measured signals at each relay location, (v) designing a protection algorithm that detects and locates DC-side faults reliably and sufficiently fast to prevent relay malfunction and unnecessary blocking of the converters, and (vi) performing hardware-in-the-loop tests on the designed relay to verify its potential to be implemented in hardware. The results of the off-line time domain transients studies in the PSCAD software platform and the real-time hardware-in-the-loop tests using an enhanced version of the RTDS platform indicate that the developed HVDC grid relay meets all technical requirements including speed, dependability, security, selectivity, and robustness. Moreover, the developed protection algorithm does not impose considerable computational burden on the hardware.

Grid Work

NASA Technical Reports Server (NTRS)

1998-01-01

Pointwise Inc.'s, Gridgen Software is a system for the generation of 3D (three dimensional) multiple block, structured grids. Gridgen is a visually-oriented, graphics-based interactive code used to decompose a 3D domain into blocks, distribute grid points on curves, initialize and refine grid points on surfaces and initialize volume grid points. Gridgen is available to U.S. citizens and American-owned companies by license.

Issues regarding the usage of MPPT techniques in micro grid systems

NASA Astrophysics Data System (ADS)

Szeidert, I.; Filip, I.; Dragan, F.; Gal, A.

2018-01-01

The main objective of the control strategies applied at hybrid micro grid systems (wind/hydro/solar), that function based on maximum power point tracking (MPPT) techniques is to improve the conversion system’s efficiency and to preserve the quality of the generated electrical energy (voltage and power factor). One of the main goals of maximum power point tracking strategy is to achieve the harvesting of the maximal possible energy within a certain time period. In order to implement the control strategies for micro grid, there are typically required specific transducers (sensor for wind speed, optical rotational transducers, etc.). In the technical literature, several variants of the MPPT techniques are presented and particularized at some applications (wind energy conversion systems, solar systems, hydro plants, micro grid hybrid systems). The maximum power point tracking implementations are mainly based on two-level architecture. The lower level controls the main variable and the superior level represents the MPPT control structure. The paper presents micro grid structures developed at Politehnica University Timisoara (PUT) within the frame of a research grant. The paper is focused on the application of MPPT strategies on hybrid micro grid systems. There are presented several structures and control strategies and are highlighted their advantages and disadvantages, together with practical implementation guidelines.

Simulation of Hawaiian Electric Companies Feeder Operations with Advanced Inverters and Analysis of Annual Photovoltaic Energy Curtailment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giraldez Miner, Julieta I.; Nagarajan, Adarsh; Gotseff, Peter

The Hawaiian Electric Companies achieved a consolidated Renewable Portfolio Standard (RPS) of approximately 26% at the end of 2016. This significant RPS performance was achieved using various renewable energy sources - biomass, geothermal, solar photovoltaic (PV) systems, hydro, wind, and biofuels - and customer-sited, grid-connected technologies (primarily private rooftop solar PV systems). The Hawaiian Electric Companies are preparing grid-modernization plans for the island grids. The plans outline specific near-term actions to accelerate the achievement of Hawai'i's 100% RPS by 2045. A key element of the Companies' grid-modernization strategy is to utilize new technologies - including storage and PV systems withmore » grid-supportive inverters - that will help to more than triple the amount of private rooftop solar PV systems. The Hawaiian Electric Companies collaborated with the Smart Inverter Technical Working Group Hawai'i (SITWG) to partner with the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to research the implementation of advanced inverter grid support functions (GSF). Together with the technical guidance from the Companies's planning engineers and stakeholder input from the SITWG members, NREL proposed a scope of work that explored different modes of voltage-regulation GSF to better understand the trade-offs of the grid benefits and curtailment impacts from the activation of selected advanced inverter grid support functions. The simulation results presented in this report examine the effectiveness in regulating voltage as well as the impact to the utility and the customers of various inverter-based grid support functions on two Hawaiian Electric distribution substations.« less

Meter Scale Heterogeneities in the Oceanic Mantle Revealed in Ophiolites Peridotites

NASA Astrophysics Data System (ADS)

Haller, M. B.; Walker, R. J.; Day, J. M.; O'Driscoll, B.; Daly, J. S.

2016-12-01

Mid-ocean ridge basalts and other oceanic mantle-derived rocks do not capture the depleted endmember isotopic compositions present in oceanic peridotites. Ophiolites are especially useful in interrogating this issue as field-based observations can be paired with geochemical investigations over a wide range of geologic time. Grid sampling methods (3m x 3m) at the 497 Ma Leka Ophiolite Complex (LOC), Norway, and the 1.95 Ga Jormua Ophiolite Complex (JOC), Finland, offer an opportunity to study mantle domains at the meter and kilometer scale, and over a one billion year timespan. The lithology of each locality predominately comprises harzburgite, hosting layers and lenses of dunite and pyroxenite. Here, we combine highly siderophile elements (HSE) and Re-Os isotopic analysis of these rocks with major and trace element measurements. Harzburgites at individual LOC grid sites show variations in γOs(497 Ma) (-2.1 to +2.2) at the meter scale. Analyses of adjacent, more radiogenic dunites within the same LOC grid, reveal that dunites may either have similar γOs to their host harzburgite, or different, implying interactions between spatially associated rock types may differ at the meter scale. Averaged γOs values between the mantle sections of two LOC grid sites (+1.3 and -0.4) separated by 5 km indicate km-scale heterogeneity in the convecting upper mantle. Pd/Ir and Ru/Ir ratios are scattered and do not obviously correlate with γOs values. Analyses of pyroxenites within LOC grid sections, thin section observations of relict olivine grains, and whole rock major and trace element data are also examined to shed light on the causes of the isotopic heterogeneities in the LOC. Data from JOC grid sampling will be presented as well.

Two-boundary grid generation for the solution of the three dimensional compressible Navier-Stokes equations. Ph.D. Thesis - Old Dominion Univ.

NASA Technical Reports Server (NTRS)

Smith, R. E.

1981-01-01

A grid generation technique called the two boundary technique is developed and applied for the solution of the three dimensional Navier-Stokes equations. The Navier-Stokes equations are transformed from a cartesian coordinate system to a computational coordinate system, and the grid generation technique provides the Jacobian matrix describing the transformation. The two boundary technique is based on algebraically defining two distinct boundaries of a flow domain and the distribution of the grid is achieved by applying functions to the uniform computational grid which redistribute the computational independent variables and consequently concentrate or disperse the grid points in the physical domain. The Navier-Stokes equations are solved using a MacCormack time-split technique. Grids and supersonic laminar flow solutions are obtained for a family of three dimensional corners and two spike-nosed bodies.

Refined Three-Dimensional Modelling of Thermally-Driven Flow in the Bormio System (Central Italian Alps)

NASA Astrophysics Data System (ADS)

Volpi, Giorgio; Riva, Federico; Frattini, Paolo; Battista Crosta, Giovanni; Magri, Fabien

2016-04-01

Thermal springs are widespread in the European Alps, where more than 80 geothermal sites are known and exploited. The quantitative assessment of those thermal flow systems is a challenging issue and requires accurate conceptual model and a thorough understanding of thermo-hydraulic properties of the aquifers. Accordingly in the last years, several qualitative studies were carried out to understand the heat and fluid transport processes driving deep fluids from the reservoir to the springs. Our work focused on thermal circulation and fluid outflows of the area around Bormio (Central Italian Alps), where nine geothermal springs discharge from dolomite bodies located close to a regional alpine thrust, called the Zebrù Line. At this site, water is heated in deep circulation systems and vigorously upwells at temperature of about 40°C. The aim of this paper is to explore the mechanisms of heat and fluid transport in the Bormio area by carrying out refined steady and transient three-dimensional finite element simulations of thermally-driven flow and to quantitatively assess the source area of the thermal waters. The full regional model (ca. 700 km2) is discretized with a highly refined triangular finite element planar grid obtained with Midas GTS NX software. The structural 3D features of the regional Zebrù thrust are built by interpolating series of geological cross sections using Fracman. A script was developed to convert and implement the thrust grid into FEFLOW mesh that comprises ca. 4 million elements. The numerical results support the observed discharge rates and temperature field within the simulated domain. Flow and temperature patterns suggest that thermal groundwater flows through a deep system crossing both sedimentary and metamorphic lithotypes, and a fracture network associated to the thrust system. Besides providing a numerical framework to simulate complex fractured systems, this example gives insights into the influence of deep alpine structures on groundwater circulation that underlies the development of many hydrothermal systems.

Electrically heated particulate filter enhanced ignition strategy

DOEpatents

Gonze, Eugene V; Paratore, Jr., Michael J

2012-10-23

An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating applied to at least one of the PF and the grid. A control module estimates a temperature of the grid and controls the engine to produce a desired exhaust product to increase the temperature of the grid.

Design of A Grid Integrated PV System with MPPT Control and Voltage Oriented Controller using MATLAB/PLECES

NASA Astrophysics Data System (ADS)

Soreng, Bineeta; Behera, Pradyumna; Pradhan, Raseswari

2017-08-01

This paper presents model of a grid-integrated photovoltaic array with Maximum Power Point Tracker (MPPT) and voltage oriented controller. The MPPT of the PV array is usually an essential part of PV system as MPPT helps the operating point of the solar array to align its maximum power point. In this model, the MPPT along with a DC-DC converter lets a PV generator to produce continuous power, despite of the measurement conditions. The neutral-point-clamped converter (NPC) with a boost converter raises the voltage from the panels to the DC-link. An LCL-filter smoothens the current ripple caused by the PWM modulation of the grid-side inverter. In addition to the MPPT, the system has two more two controllers, such as voltage controller and a current controller. The voltage control has a PI controller to regulate the PV voltage to optimal level by controlling the amount of current injected into the boost stage. Here, the grid-side converter transfers the power from the DC-link into the grid and maintains the DC-link voltage. Three-phase PV inverters are used for off-grid or designed to create utility frequency AC. The PV system can be connected in series or parallel to get the desired output power. To justify the working of this model, the grid-integrated PV system has been designed in MATLAB/PLECS. The simulation shows the P-V curve of implemented PV Array consisting 4 X 20 modules, reactive, real power, grid voltage and current.

Spatiotemporal variation of long-term drought propensity through reliability-resilience-vulnerability based Drought Management Index

NASA Astrophysics Data System (ADS)

Chanda, Kironmala; Maity, Rajib; Sharma, Ashish; Mehrotra, Rajeshwar

2014-10-01

This paper characterizes the long-term, spatiotemporal variation of drought propensity through a newly proposed, namely Drought Management Index (DMI), and explores its predictability in order to assess the future drought propensity and adapt drought management policies for a location. The DMI was developed using the reliability-resilience-vulnerability (RRV) rationale commonly used in water resources systems analysis, under the assumption that depletion of soil moisture across a vertical soil column is equivalent to the operation of a water supply reservoir, and that drought should be managed not simply using a measure of system reliability, but should also take into account the readiness of the system to bounce back from drought to a normal state. Considering India as a test bed, 5 year long monthly gridded (0.5° Lat × 0.5° Lon) soil moisture data are used to compute the RRV at each grid location falling within the study domain. The Permanent Wilting Point (PWP) is used as the threshold, indicative of transition into water stress. The association between resilience and vulnerability is then characterized through their joint probability distribution ascertained using Plackett copula models for four broad soil types across India. The joint cumulative distribution functions (CDF) of resilience and vulnerability form the basis for estimating the DMI as a five-yearly time series at each grid location assessed. The status of DMI over the past 50 years indicate that drought propensity is consistently low toward northern and north eastern parts of India but higher in the western part of peninsular India. Based on the observed past behavior of DMI series on a climatological time scale, a DMI prediction model comprising deterministic and stochastic components is developed. The predictability of DMI for a lead time of 5 years is found to vary across India, with a Pearson correlation coefficient between observed and predicted DMI above 0.6 over most of the study area, indicating a reasonably good potential for drought management in the medium term water resources planning horizon.

Electrolyzers Enhancing Flexibility in Electric Grids

DOE PAGES

Mohanpurkar, Manish; Luo, Yusheng; Terlip, Danny; ...

2017-11-10

This paper presents a real-time simulation with a hardware-in-the-loop (HIL)-based approach for verifying the performance of electrolyzer systems in providing grid support. Hydrogen refueling stations may use electrolyzer systems to generate hydrogen and are proposed to have the potential of becoming smarter loads that can proactively provide grid services. On the basis of experimental findings, electrolyzer systems with balance of plant are observed to have a high level of controllability and hence can add flexibility to the grid from the demand side. A generic front end controller (FEC) is proposed, which enables an optimal operation of the load on themore » basis of market and grid conditions. This controller has been simulated and tested in a real-time environment with electrolyzer hardware for a performance assessment. It can optimize the operation of electrolyzer systems on the basis of the information collected by a communication module. Real-time simulation tests are performed to verify the performance of the FEC-driven electrolyzers to provide grid support that enables flexibility, greater economic revenue, and grid support for hydrogen producers under dynamic conditions. In conclusion, the FEC proposed in this paper is tested with electrolyzers, however, it is proposed as a generic control topology that is applicable to any load.« less

Sensing, Measurement, and Forecasting | Grid Modernization | NREL

Science.gov Websites

into operational intelligence to support grid operations and planning. Photo of solar resource monitoring equipment Grid operations involve assessing the grid's health in real time, predicting its to hours and days-to support advances in power system operations and planning. Capabilities Solar

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras.

PubMed

Bolotnikov, A E; Ackley, K; Camarda, G S; Cherches, C; Cui, Y; De Geronimo, G; Fried, J; Hodges, D; Hossain, A; Lee, W; Mahler, G; Maritato, M; Petryk, M; Roy, U; Salwen, C; Vernon, E; Yang, G; James, R B

2015-07-01

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

DOE PAGES

Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.; ...

2015-07-28

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm 3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readoutmore » electronics. The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

Air Force Global Weather Central System Architecture Study. Final System/Subsystem Summary Report. Volume 4. Systems Analysis and Trade Studies

DTIC Science & Technology

1976-03-01

atmosphere,as well as very fine grid cloud models and cloud probability models. Some of the new requirements that will be supported with this system are a...including the Advanced Prediction Model for the global atmosphere, as well as very fine grid cloud models and cloud proba- bility models. Some of the new...with the mapping and gridding function (imput and output)? Should the capability exist to interface raw ungridded data with the SID interface

Advanced Distribution Management Systems | Grid Modernization | NREL

Science.gov Websites

Advanced Distribution Management Systems Advanced Distribution Management Systems Electric utilities are investing in updated grid technologies such as advanced distribution management systems to management testbed for cyber security in power systems. The "advanced" elements of advanced

Foundations for Protecting Renewable-Rich Distribution Systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, Abraham; Brahma, Sukumar; Ranade, Satish

High proliferation of Inverter Interfaced Distributed Energy Resources (IIDERs) into the electric distribution grid introduces new challenges to protection of such systems. This is because the existing protection systems are designed with two assumptions: 1) system is single-sourced, resulting in unidirectional fault current, and (2) fault currents are easily detectable due to much higher magnitudes compared to load currents. Due to the fact that most renewables interface with the grid though inverters, and inverters restrict their current output to levels close to the full load currents, both these assumptions are no longer valid - the system becomes multi-sourced, and overcurrent-basedmore » protection does not work. The primary scope of this study is to analyze the response of a grid-tied inverter to different faults in the grid, leading to new guidelines on protecting renewable-rich distribution systems.« less

Output Control Technologies for a Large-scale PV System Considering Impacts on a Power Grid

NASA Astrophysics Data System (ADS)

Kuwayama, Akira

The mega-solar demonstration project named “Verification of Grid Stabilization with Large-scale PV Power Generation systems” had been completed in March 2011 at Wakkanai, the northernmost city of Japan. The major objectives of this project were to evaluate adverse impacts of large-scale PV power generation systems connected to the power grid and develop output control technologies with integrated battery storage system. This paper describes the outline and results of this project. These results show the effectiveness of battery storage system and also proposed output control methods for a large-scale PV system to ensure stable operation of power grids. NEDO, New Energy and Industrial Technology Development Organization of Japan conducted this project and HEPCO, Hokkaido Electric Power Co., Inc managed the overall project.

Near-Body Grid Adaption for Overset Grids

NASA Technical Reports Server (NTRS)

Buning, Pieter G.; Pulliam, Thomas H.

2016-01-01

A solution adaption capability for curvilinear near-body grids has been implemented in the OVERFLOW overset grid computational fluid dynamics code. The approach follows closely that used for the Cartesian off-body grids, but inserts refined grids in the computational space of original near-body grids. Refined curvilinear grids are generated using parametric cubic interpolation, with one-sided biasing based on curvature and stretching ratio of the original grid. Sensor functions, grid marking, and solution interpolation tasks are implemented in the same fashion as for off-body grids. A goal-oriented procedure, based on largest error first, is included for controlling growth rate and maximum size of the adapted grid system. The adaption process is almost entirely parallelized using MPI, resulting in a capability suitable for viscous, moving body simulations. Two- and three-dimensional examples are presented.

Adaptive EAGLE dynamic solution adaptation and grid quality enhancement

NASA Technical Reports Server (NTRS)

Luong, Phu Vinh; Thompson, J. F.; Gatlin, B.; Mastin, C. W.; Kim, H. J.

1992-01-01

In the effort described here, the elliptic grid generation procedure in the EAGLE grid code was separated from the main code into a subroutine, and a new subroutine which evaluates several grid quality measures at each grid point was added. The elliptic grid routine can now be called, either by a computational fluid dynamics (CFD) code to generate a new adaptive grid based on flow variables and quality measures through multiple adaptation, or by the EAGLE main code to generate a grid based on quality measure variables through static adaptation. Arrays of flow variables can be read into the EAGLE grid code for use in static adaptation as well. These major changes in the EAGLE adaptive grid system make it easier to convert any CFD code that operates on a block-structured grid (or single-block grid) into a multiple adaptive code.

Quantitative Analysis Method of Output Loss due to Restriction for Grid-connected PV Systems

NASA Astrophysics Data System (ADS)

Ueda, Yuzuru; Oozeki, Takashi; Kurokawa, Kosuke; Itou, Takamitsu; Kitamura, Kiyoyuki; Miyamoto, Yusuke; Yokota, Masaharu; Sugihara, Hiroyuki

Voltage of power distribution line will be increased due to reverse power flow from grid-connected PV systems. In the case of high density grid connection, amount of voltage increasing will be higher than the stand-alone grid connection system. To prevent the over voltage of power distribution line, PV system's output will be restricted if the voltage of power distribution line is close to the upper limit of the control range. Because of this interaction, amount of output loss will be larger in high density case. This research developed a quantitative analysis method for PV systems output and losses to clarify the behavior of grid connected PV systems. All the measured data are classified into the loss factors using 1 minute average of 1 second data instead of typical 1 hour average. Operation point on the I-V curve is estimated to quantify the loss due to the output restriction using module temperature, array output voltage, array output current and solar irradiance. As a result, loss due to output restriction is successfully quantified and behavior of output restriction is clarified.

Study of a close-grid geodynamic measurement system

NASA Technical Reports Server (NTRS)

1977-01-01

The Clogeos (Close-Grid Geodynamic Measurement System) concept, a complete range or range-rate measurement terminal installed in a satellite in a near-polar orbit with a network of relatively simple transponders or retro-reflectors on the ground at intervals of 0.1 to 10 km was reviewed. The distortion of the grid was measured in three dimensions to accuracies of + or - 1 cm with important applications to geodynamics, glaciology, and geodesy. User requirements are considered, and a typical grid, designed for earthquake prediction, was laid out along the San Andreas, Hayward, and Calaceras faults in southern California. The sensitivity of both range and range-rate measurements to small grid motions was determined by a simplified model. Variables in the model are satellite altitude and elevation angle plus grid displacements in latitude, and height.

Characterization of Slosh Damping for Ortho-Grid and Iso-Grid Internal Tank Structures

NASA Technical Reports Server (NTRS)

Westra, Douglas G.; Sansone, Marco D.; Eberhart, Chad J.; West, Jeffrey S.

2016-01-01

Grid stiffened tank structures such as Ortho-Grid and Iso-Grid are widely used in cryogenic tanks for providing stiffening to the tank while reducing mass, compared to tank walls of constant cross-section. If the structure is internal to the tank, it will positively affect the fluid dynamic behavior of the liquid propellant, in regard to fluid slosh damping. As NASA and commercial companies endeavor to explore the solar system, vehicles will by necessity become more mass efficient, and design margin will be reduced where possible. Therefore, if the damping characteristics of the Ortho-Grid and Iso-Grid structure is understood, their positive damping effect can be taken into account in the systems design process. Historically, damping by internal structures has been characterized by rules of thumb and for Ortho-Grid, empirical design tools intended for slosh baffles of much larger cross-section have been used. There is little or no information available to characterize the slosh behavior of Iso-Grid internal structure. Therefore, to take advantage of these structures for their positive damping effects, there is much need for obtaining additional data and tools to characterize them. Recently, the NASA Marshall Space Flight Center conducted both sub-scale testing and computational fluid dynamics (CFD) simulations of slosh damping for Ortho-Grid and Iso-Grid tanks for cylindrical tanks containing water. Enhanced grid meshing techniques were applied to the geometrically detailed and complex Ortho-Grid and Iso-Grid structures. The Loci-STREAM CFD program with the Volume of Fluid Method module for tracking and locating the water-air fluid interface was used to conduct the simulations. The CFD simulations were validated with the test data and new empirical models for predicting damping and frequency of Ortho-Grid and Iso-Grid structures were generated.

Hydroacoustic propagation grids for the CTBT knowledge databaes BBN technical memorandum W1303

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. Angell

1998-05-01

The Hydroacoustic Coverage Assessment Model (HydroCAM) has been used to develop components of the hydroacoustic knowledge database required by operational monitoring systems, particularly the US National Data Center (NDC). The database, which consists of travel time, amplitude correction and travel time standard deviation grids, is planned to support source location, discrimination and estimation functions of the monitoring network. The grids will also be used under the current BBN subcontract to support an analysis of the performance of the International Monitoring System (IMS) and national sensor systems. This report describes the format and contents of the hydroacoustic knowledgebase grids, and themore » procedures and model parameters used to generate these grids. Comparisons between the knowledge grids, measured data and other modeled results are presented to illustrate the strengths and weaknesses of the current approach. A recommended approach for augmenting the knowledge database with a database of expected spectral/waveform characteristics is provided in the final section of the report.« less

Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 3: Advanced Fan Section Grid Generator Final Report and Computer Program User's Manual

NASA Technical Reports Server (NTRS)

Crook, Andrew J.; Delaney, Robert A.

1991-01-01

A procedure is studied for generating three-dimensional grids for advanced turbofan engine fan section geometries. The procedure constructs a discrete mesh about engine sections containing the fan stage, an arbitrary number of axisymmetric radial flow splitters, a booster stage, and a bifurcated core/bypass flow duct with guide vanes. The mesh is an h-type grid system, the points being distributed with a transfinite interpolation scheme with axial and radial spacing being user specified. Elliptic smoothing of the grid in the meridional plane is a post-process option. The grid generation scheme is consistent with aerodynamic analyses utilizing the average-passage equation system developed by Dr. John Adamczyk of NASA Lewis. This flow solution scheme requires a series of blade specific grids each having a common axisymmetric mesh, but varying in the circumferential direction according to the geometry of the specific blade row.

WENO schemes on arbitrary mixed-element unstructured meshes in three space dimensions

NASA Astrophysics Data System (ADS)

Tsoutsanis, P.; Titarev, V. A.; Drikakis, D.

2011-02-01

The paper extends weighted essentially non-oscillatory (WENO) methods to three dimensional mixed-element unstructured meshes, comprising tetrahedral, hexahedral, prismatic and pyramidal elements. Numerical results illustrate the convergence rates and non-oscillatory properties of the schemes for various smooth and discontinuous solutions test cases and the compressible Euler equations on various types of grids. Schemes of up to fifth order of spatial accuracy are considered.

Ion beam accelerator system

NASA Technical Reports Server (NTRS)

Aston, G. (Inventor)

1981-01-01

A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

Information Theoretically Secure, Enhanced Johnson Noise Based Key Distribution over the Smart Grid with Switched Filters

PubMed Central

2013-01-01

We introduce a protocol with a reconfigurable filter system to create non-overlapping single loops in the smart power grid for the realization of the Kirchhoff-Law-Johnson-(like)-Noise secure key distribution system. The protocol is valid for one-dimensional radial networks (chain-like power line) which are typical of the electricity distribution network between the utility and the customer. The speed of the protocol (the number of steps needed) versus grid size is analyzed. When properly generalized, such a system has the potential to achieve unconditionally secure key distribution over the smart power grid of arbitrary geometrical dimensions. PMID:23936164

Information theoretically secure, enhanced Johnson noise based key distribution over the smart grid with switched filters.

PubMed

Gonzalez, Elias; Kish, Laszlo B; Balog, Robert S; Enjeti, Prasad

2013-01-01

We introduce a protocol with a reconfigurable filter system to create non-overlapping single loops in the smart power grid for the realization of the Kirchhoff-Law-Johnson-(like)-Noise secure key distribution system. The protocol is valid for one-dimensional radial networks (chain-like power line) which are typical of the electricity distribution network between the utility and the customer. The speed of the protocol (the number of steps needed) versus grid size is analyzed. When properly generalized, such a system has the potential to achieve unconditionally secure key distribution over the smart power grid of arbitrary geometrical dimensions.

Distributed Energy Systems Integration and Demand Optimization for Autonomous Operations and Electric Grid Transactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghatikar, Girish; Mashayekh, Salman; Stadler, Michael

Distributed power systems in the U.S. and globally are evolving to provide reliable and clean energy to consumers. In California, existing regulations require significant increases in renewable generation, as well as identification of customer-side distributed energy resources (DER) controls, communication technologies, and standards for interconnection with the electric grid systems. As DER deployment expands, customer-side DER control and optimization will be critical for system flexibility and demand response (DR) participation, which improves the economic viability of DER systems. Current DER systems integration and communication challenges include leveraging the existing DER and DR technology and systems infrastructure, and enabling optimized cost,more » energy and carbon choices for customers to deploy interoperable grid transactions and renewable energy systems at scale. Our paper presents a cost-effective solution to these challenges by exploring communication technologies and information models for DER system integration and interoperability. This system uses open standards and optimization models for resource planning based on dynamic-pricing notifications and autonomous operations within various domains of the smart grid energy system. It identifies architectures and customer engagement strategies in dynamic DR pricing transactions to generate feedback information models for load flexibility, load profiles, and participation schedules. The models are tested at a real site in California—Fort Hunter Liggett (FHL). Furthermore, our results for FHL show that the model fits within the existing and new DR business models and networked systems for transactive energy concepts. Integrated energy systems, communication networks, and modeling tools that coordinate supply-side networks and DER will enable electric grid system operators to use DER for grid transactions in an integrated system.« less

Connection technology of HPTO type WECs and DC nano grid in island

NASA Astrophysics Data System (ADS)

Wang, Kun-lin; Tian, Lian-fang; You, Ya-ge; Wang, Xiao-hong; Sheng, Song-wei; Zhang, Ya-qun; Ye, Yin

2016-07-01

Wave energy fluctuating a great deal endangers the security of power grid especially micro grid in island. A DC nano grid supported by batteries is proposed to smooth the output power of wave energy converters (WECs). Thus, renewable energy converters connected to DC grid is a new subject. The characteristics of WECs are very important to the connection technology of HPTO type WECs and DC nano grid. Hydraulic power take-off system (HPTO) is the core unit of the largest category of WECs, with the functions of supplying suitable damping for a WEC to absorb wave energy, and converting captured wave energy to electricity. The HPTO is divided into a hydraulic energy storage system (HESS) and a hydraulic power generation system (HPGS). A primary numerical model for the HPGS is established in this paper. Three important basic characteristics of the HPGS are deduced, which reveal how the generator load determines the HPGS rotation rate. Therefore, the connector of HPTO type WEC and DC nano grid would be an uncontrollable rectifier with high reliability, also would be a controllable power converter with high efficiency, such as interleaved boost converter-IBC. The research shows that it is very flexible to connect to DC nano grid for WECs, but bypass resistance loads are indispensable for the security of WECs.

GridKit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peles, Slaven

2016-11-06

GridKit is a software development kit for interfacing power systems and power grid application software with high performance computing (HPC) libraries developed at National Labs and academia. It is also intended as interoperability layer between different numerical libraries. GridKit is not a standalone application, but comes with a suite of test examples illustrating possible usage.

Scheduling quality of precise form sets which consist of tasks of circular type in GRID systems

NASA Astrophysics Data System (ADS)

Saak, A. E.; Kureichik, V. V.; Kravchenko, Y. A.

2018-05-01

Users’ demand in computer power and rise of technology favour the arrival of Grid systems. The quality of Grid systems’ performance depends on computer and time resources scheduling. Grid systems with a centralized structure of the scheduling system and user’s task are modeled by resource quadrant and re-source rectangle accordingly. A Non-Euclidean heuristic measure, which takes into consideration both the area and the form of an occupied resource region, is used to estimate scheduling quality of heuristic algorithms. The authors use sets, which are induced by the elements of square squaring, as an example of studying the adapt-ability of a level polynomial algorithm with an excess and the one with minimal deviation.

Research on Resilience of Power Systems Under Natural Disasters—A Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yezhou; Chen, Chen; Wang, Jianhui

2016-03-01

Natural disasters can cause large blackouts. Research into natural disaster impacts on electric power systems is emerging to understand the causes of the blackouts, explore ways to prepare and harden the grid, and increase the resilience of the power grid under such events. At the same time, new technologies such as smart grid, micro grid, and wide area monitoring applications could increase situational awareness as well as enable faster restoration of the system. This paper aims to consolidate and review the progress of the research field towards methods and tools of forecasting natural disaster related power system disturbances, hardening andmore » pre-storm operations, and restoration models. Challenges and future research opportunities are also presented in the paper.« less

A Systematic Multi-Time Scale Solution for Regional Power Grid Operation

NASA Astrophysics Data System (ADS)

Zhu, W. J.; Liu, Z. G.; Cheng, T.; Hu, B. Q.; Liu, X. Z.; Zhou, Y. F.

2017-10-01

Many aspects need to be taken into consideration in a regional grid while making schedule plans. In this paper, a systematic multi-time scale solution for regional power grid operation considering large scale renewable energy integration and Ultra High Voltage (UHV) power transmission is proposed. In the time scale aspect, we discuss the problem from month, week, day-ahead, within-day to day-behind, and the system also contains multiple generator types including thermal units, hydro-plants, wind turbines and pumped storage stations. The 9 subsystems of the scheduling system are described, and their functions and relationships are elaborated. The proposed system has been constructed in a provincial power grid in Central China, and the operation results further verified the effectiveness of the system.

Integrating Grid Services into the Cray XT4 Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

NERSC; Cholia, Shreyas; Lin, Hwa-Chun Wendy

2009-05-01

The 38640 core Cray XT4"Franklin" system at the National Energy Research Scientific Computing Center (NERSC) is a massively parallel resource available to Department of Energy researchers that also provides on-demand grid computing to the Open Science Grid. The integration of grid services on Franklin presented various challenges, including fundamental differences between the interactive and compute nodes, a stripped down compute-node operating system without dynamic library support, a shared-root environment and idiosyncratic application launching. Inour work, we describe how we resolved these challenges on a running, general-purpose production system to provide on-demand compute, storage, accounting and monitoring services through generic gridmore » interfaces that mask the underlying system-specific details for the end user.« less

Grist : grid-based data mining for astronomy

NASA Technical Reports Server (NTRS)

Jacob, Joseph C.; Katz, Daniel S.; Miller, Craig D.; Walia, Harshpreet; Williams, Roy; Djorgovski, S. George; Graham, Matthew J.; Mahabal, Ashish; Babu, Jogesh; Berk, Daniel E. Vanden;

Grist: Grid-based Data Mining for Astronomy

NASA Astrophysics Data System (ADS)

Jacob, J. C.; Katz, D. S.; Miller, C. D.; Walia, H.; Williams, R. D.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A. A.; Babu, G. J.; vanden Berk, D. E.; Nichol, R.

2005-12-01

The Grist project is developing a grid-technology based system as a research environment for astronomy with massive and complex datasets. This knowledge extraction system will consist of a library of distributed grid services controlled by a workflow system, compliant with standards emerging from the grid computing, web services, and virtual observatory communities. This new technology is being used to find high redshift quasars, study peculiar variable objects, search for transients in real time, and fit SDSS QSO spectra to measure black hole masses. Grist services are also a component of the ``hyperatlas'' project to serve high-resolution multi-wavelength imagery over the Internet. In support of these science and outreach objectives, the Grist framework will provide the enabling fabric to tie together distributed grid services in the areas of data access, federation, mining, subsetting, source extraction, image mosaicking, statistics, and visualization.

An unstructured-grid software system for solving complex aerodynamic problems

NASA Technical Reports Server (NTRS)

Frink, Neal T.; Pirzadeh, Shahyar; Parikh, Paresh

1995-01-01

A coordinated effort has been underway over the past four years to elevate unstructured-grid methodology to a mature level. The goal of this endeavor is to provide a validated capability to non-expert users for performing rapid aerodynamic analysis and design of complex configurations. The Euler component of the system is well developed, and is impacting a broad spectrum of engineering needs with capabilities such as rapid grid generation and inviscid flow analysis, inverse design, interactive boundary layers, and propulsion effects. Progress is also being made in the more tenuous Navier-Stokes component of the system. A robust grid generator is under development for constructing quality thin-layer tetrahedral grids, along with a companion Navier-Stokes flow solver. This paper presents an overview of this effort, along with a perspective on the present and future status of the methodology.

HEP Data Grid Applications in Korea

NASA Astrophysics Data System (ADS)

Cho, Kihyeon; Oh, Youngdo; Son, Dongchul; Kim, Bockjoo; Lee, Sangsan

2003-04-01

We will introduce the national HEP Data Grid applications in Korea. Through a five-year HEP Data Grid project (2002-2006) for CMS, AMS, CDF, PHENIX, K2K and Belle experiments in Korea, the Center for High Energy Physics, Kyungpook National University in Korea will construct the 1,000 PC cluster and related storage system such as 1,200 TByte Raid disk system. This project includes one of the master plan to construct Asia Regional Data Center by 2006 for the CMS and AMS Experiments and DCAF(DeCentralized Analysis Farm) for the CDF Experiments. During the first year of the project, we have constructed a cluster of around 200 CPU's with a 50 TBytes of a storage system. We will present our first year's experience of the software and hardware applications for HEP Data Grid of EDG and SAM Grid testbeds.

Feasibility analysis of a smart grid photovoltaics system for the subarctic rural region in Alaska

NASA Astrophysics Data System (ADS)

Yao, Lei

A smart grid photovoltaics system was developed to demonstrate that the system is feasible for a similar off-grid rural community in the subarctic region in Alaska. A system generation algorithm and a system business model were developed to determine feasibility. Based on forecasts by the PV F-Chart software, a 70° tilt angle in winter, and a 34° tilt angle in summer were determined to be the best angles for electrical output. The proposed system's electricity unit cost was calculated at 32.3 cents/kWh that is cheaper than current unsubsidized electricity price (46.8 cents/kWh) in off-grid rural communities. Given 46.8 cents/kWh as the electricity unit price, the system provider can break even when 17.3 percent of the total electrical revenue through power generated by the proposed system is charged. Given these results, the system can be economically feasible during the life-cycle period. With further incentives, the system may have a competitive advantage.

Past Seminars and Workshops | Energy Systems Integration Facility | NREL

Science.gov Websites

Distributed Optimization and Control of Sustainable Power Systems Workshop Integrating PV in Distributed Grids Unintentional Islands in Power Systems with Distributed Resources Webinar Smart Grid Educational Series Energy

Rotational-translational fourier imaging system

NASA Technical Reports Server (NTRS)

Campbell, Jonathan W. (Inventor)

2004-01-01

This invention has the ability to create Fourier-based images with only two grid pairs. The two grid pairs are manipulated in a manner that allows (1) a first grid pair to provide multiple real components of the Fourier-based image and (2) a second grid pair to provide multiple imaginary components of the Fourier-based image. The novelty of this invention resides in the use of only two grid pairs to provide the same imaging information that has been traditionally collected with multiple grid pairs.

Flexible network wireless transceiver and flexible network telemetry transceiver

DOEpatents

Brown, Kenneth D.

2008-08-05

A transceiver for facilitating two-way wireless communication between a baseband application and other nodes in a wireless network, wherein the transceiver provides baseband communication networking and necessary configuration and control functions along with transmitter, receiver, and antenna functions to enable the wireless communication. More specifically, the transceiver provides a long-range wireless duplex communication node or channel between the baseband application, which is associated with a mobile or fixed space, air, water, or ground vehicle or other platform, and other nodes in the wireless network or grid. The transceiver broadly comprises a communication processor; a flexible telemetry transceiver including a receiver and a transmitter; a power conversion and regulation mechanism; a diplexer; and a phased array antenna system, wherein these various components and certain subcomponents thereof may be separately enclosed and distributable relative to the other components and subcomponents.

Monitoring System for the GRID Monte Carlo Mass Production in the H1 Experiment at DESY

NASA Astrophysics Data System (ADS)

Bystritskaya, Elena; Fomenko, Alexander; Gogitidze, Nelly; Lobodzinski, Bogdan

2014-06-01

The H1 Virtual Organization (VO), as one of the small VOs, employs most components of the EMI or gLite Middleware. In this framework, a monitoring system is designed for the H1 Experiment to identify and recognize within the GRID the best suitable resources for execution of CPU-time consuming Monte Carlo (MC) simulation tasks (jobs). Monitored resources are Computer Elements (CEs), Storage Elements (SEs), WMS-servers (WMSs), CernVM File System (CVMFS) available to the VO HONE and local GRID User Interfaces (UIs). The general principle of monitoring GRID elements is based on the execution of short test jobs on different CE queues using submission through various WMSs and directly to the CREAM-CEs as well. Real H1 MC Production jobs with a small number of events are used to perform the tests. Test jobs are periodically submitted into GRID queues, the status of these jobs is checked, output files of completed jobs are retrieved, the result of each job is analyzed and the waiting time and run time are derived. Using this information, the status of the GRID elements is estimated and the most suitable ones are included in the automatically generated configuration files for use in the H1 MC production. The monitoring system allows for identification of problems in the GRID sites and promptly reacts on it (for example by sending GGUS (Global Grid User Support) trouble tickets). The system can easily be adapted to identify the optimal resources for tasks other than MC production, simply by changing to the relevant test jobs. The monitoring system is written mostly in Python and Perl with insertion of a few shell scripts. In addition to the test monitoring system we use information from real production jobs to monitor the availability and quality of the GRID resources. The monitoring tools register the number of job resubmissions, the percentage of failed and finished jobs relative to all jobs on the CEs and determine the average values of waiting and running time for the involved GRID queues. CEs which do not meet the set criteria can be removed from the production chain by including them in an exception table. All of these monitoring actions lead to a more reliable and faster execution of MC requests.

Metal-free aqueous redox capacitor via proton rocking-chair system in an organic-based couple

PubMed Central

Tomai, Takaaki; Mitani, Satoshi; Komatsu, Daiki; Kawaguchi, Yuji; Honma, Itaru

2014-01-01

Safe and inexpensive energy storage devices with long cycle lifetimes and high power and energy densities are mandatory for the development of electrical power grids that connect with renewable energy sources. In this study, we demonstrated metal-free aqueous redox capacitors using couples comprising low-molecular-weight organic compounds. In addition to the electric double layer formation, proton insertion/extraction reactions between a couple consisting of inexpensive quinones/hydroquinones contributed to the energy storage. This energy storage mechanism, in which protons are shuttled back and forth between two electrodes upon charge and discharge, can be regarded as a proton rocking-chair system. The fabricated capacitor showed a large capacity (>20 Wh/kg), even in the applied potential range between 0–1 V, and high power capability (>5 A/g). The support of the organic compounds in nanoporous carbon facilitated the efficient use of the organic compounds with a lifetime of thousands of cycles. PMID:24395117

Metal-free aqueous redox capacitor via proton rocking-chair system in an organic-based couple.

PubMed

Tomai, Takaaki; Mitani, Satoshi; Komatsu, Daiki; Kawaguchi, Yuji; Honma, Itaru

2014-01-07

Safe and inexpensive energy storage devices with long cycle lifetimes and high power and energy densities are mandatory for the development of electrical power grids that connect with renewable energy sources. In this study, we demonstrated metal-free aqueous redox capacitors using couples comprising low-molecular-weight organic compounds. In addition to the electric double layer formation, proton insertion/extraction reactions between a couple consisting of inexpensive quinones/hydroquinones contributed to the energy storage. This energy storage mechanism, in which protons are shuttled back and forth between two electrodes upon charge and discharge, can be regarded as a proton rocking-chair system. The fabricated capacitor showed a large capacity (>20 Wh/kg), even in the applied potential range between 0-1 V, and high power capability (>5 A/g). The support of the organic compounds in nanoporous carbon facilitated the efficient use of the organic compounds with a lifetime of thousands of cycles.

Metal-free aqueous redox capacitor via proton rocking-chair system in an organic-based couple

NASA Astrophysics Data System (ADS)

Tomai, Takaaki; Mitani, Satoshi; Komatsu, Daiki; Kawaguchi, Yuji; Honma, Itaru

2014-01-01

Safe and inexpensive energy storage devices with long cycle lifetimes and high power and energy densities are mandatory for the development of electrical power grids that connect with renewable energy sources. In this study, we demonstrated metal-free aqueous redox capacitors using couples comprising low-molecular-weight organic compounds. In addition to the electric double layer formation, proton insertion/extraction reactions between a couple consisting of inexpensive quinones/hydroquinones contributed to the energy storage. This energy storage mechanism, in which protons are shuttled back and forth between two electrodes upon charge and discharge, can be regarded as a proton rocking-chair system. The fabricated capacitor showed a large capacity (>20 Wh/kg), even in the applied potential range between 0-1 V, and high power capability (>5 A/g). The support of the organic compounds in nanoporous carbon facilitated the efficient use of the organic compounds with a lifetime of thousands of cycles.

Surface Modeling and Grid Generation of Orbital Sciences X34 Vehicle. Phase 1

NASA Technical Reports Server (NTRS)

Alter, Stephen J.

1997-01-01

The surface modeling and grid generation requirements, motivations, and methods used to develop Computational Fluid Dynamic volume grids for the X34-Phase 1 are presented. The requirements set forth by the Aerothermodynamics Branch at the NASA Langley Research Center serve as the basis for the final techniques used in the construction of all volume grids, including grids for parametric studies of the X34. The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics (ICEM/CFD), the Grid Generation code (GRIDGEN), the Three-Dimensional Multi-block Advanced Grid Generation System (3DMAGGS) code, and Volume Grid Manipulator (VGM) code are used to enable the necessary surface modeling, surface grid generation, volume grid generation, and grid alterations, respectively. All volume grids generated for the X34, as outlined in this paper, were used for CFD simulations within the Aerothermodynamics Branch.

Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

NASA Astrophysics Data System (ADS)

Hassaine, L.; Mraoui, A.

2017-02-01

Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

Assuring image authenticity within a data grid using lossless digital signature embedding and a HIPAA-compliant auditing system

NASA Astrophysics Data System (ADS)

Lee, Jasper C.; Ma, Kevin C.; Liu, Brent J.

2008-03-01

A Data Grid for medical images has been developed at the Image Processing and Informatics Laboratory, USC to provide distribution and fault-tolerant storage of medical imaging studies across Internet2 and public domain. Although back-up policies and grid certificates guarantee privacy and authenticity of grid-access-points, there still lacks a method to guarantee the sensitive DICOM images have not been altered or corrupted during transmission across a public domain. This paper takes steps toward achieving full image transfer security within the Data Grid by utilizing DICOM image authentication and a HIPAA-compliant auditing system. The 3-D lossless digital signature embedding procedure involves a private 64 byte signature that is embedded into each original DICOM image volume, whereby on the receiving end the signature can to be extracted and verified following the DICOM transmission. This digital signature method has also been developed at the IPILab. The HIPAA-Compliant Auditing System (H-CAS) is required to monitor embedding and verification events, and allows monitoring of other grid activity as well. The H-CAS system federates the logs of transmission and authentication events at each grid-access-point and stores it into a HIPAA-compliant database. The auditing toolkit is installed at the local grid-access-point and utilizes Syslog [1], a client-server standard for log messaging over an IP network, to send messages to the H-CAS centralized database. By integrating digital image signatures and centralized logging capabilities, DICOM image integrity within the Medical Imaging and Informatics Data Grid can be monitored and guaranteed without loss to any image quality.

33 CFR 3.01-1 - General description.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Administration (NOAA) using the NAD 1983 coordinate system and projected to the WGS 1984 grid system. Both coordinate systems are geocentric and similar such that they are Global Positioning System (GPS) compatible... based upon boundaries and points located using the WGS 1984 world grid system. When referenced, the...

Optimal management of stationary lithium-ion battery system in electricity distribution grids

NASA Astrophysics Data System (ADS)

Purvins, Arturs; Sumner, Mark

2013-11-01

The present article proposes an optimal battery system management model in distribution grids for stationary applications. The main purpose of the management model is to maximise the utilisation of distributed renewable energy resources in distribution grids, preventing situations of reverse power flow in the distribution transformer. Secondly, battery management ensures efficient battery utilisation: charging at off-peak prices and discharging at peak prices when possible. This gives the battery system a shorter payback time. Management of the system requires predictions of residual distribution grid demand (i.e. demand minus renewable energy generation) and electricity price curves (e.g. for 24 h in advance). Results of a hypothetical study in Great Britain in 2020 show that the battery can contribute significantly to storing renewable energy surplus in distribution grids while being highly utilised. In a distribution grid with 25 households and an installed 8.9 kW wind turbine, a battery system with rated power of 8.9 kW and battery capacity of 100 kWh can store 7 MWh of 8 MWh wind energy surplus annually. Annual battery utilisation reaches 235 cycles in per unit values, where one unit is a full charge-depleting cycle depth of a new battery (80% of 100 kWh).

Design of a Glenn Research Center Solar Field Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) designed, developed, and installed, a 37.5 kW DC photovoltaic (PV) Solar Field in the GRC West Area in the 1970s for the purpose of testing PV panels for various space and terrestrial applications. The PV panels are arranged to provide a nominal 120 VDC. The GRC Solar Field has been extremely successful in meeting its mission. The PV panels and the supporting electrical systems are all near their end of life. GRC has designed a 72 kW DC grid-tied PV power system to replace the existing GRC West Area Solar Field. The 72 kW DC grid-tied PV power system will provide DC solar power for GRC PV testing applications, and provide AC facility power for all times that research power is not required. A grid-tied 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 for use by all. 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. The report concludes that the GRC West Area grid-tied PV power system design is viable for a reliable, maintenance free, long life power system that is of significant value to NASA and the community.

Test problems for inviscid transonic flow

NASA Technical Reports Server (NTRS)

Carlson, L. A.

1979-01-01

Solving of test problems with the TRANDES program is discussed. This method utilizes the full, inviscid, perturbation potential flow equation in a Cartesian grid system that is stretched to infinity. This equation is represented by a nonconservative system of finite difference equations that includes at supersonic points a rotated difference scheme and is solved by column relaxation. The solution usually starts from a zero perturbation potential on a very coarse grid (typically 13 by 7) followed by several grid halvings until a final solution is obtained on a fine grid (97 by 49).

AGIS: The ATLAS Grid Information System

NASA Astrophysics Data System (ADS)

Anisenkov, Alexey; Belov, Sergey; Di Girolamo, Alessandro; Gayazov, Stavro; Klimentov, Alexei; Oleynik, Danila; Senchenko, Alexander

2012-12-01

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The experiment produces petabytes of data annually through simulation production and tens petabytes of data per year from the detector itself. The ATLAS Computing model embraces the Grid paradigm and a high degree of decentralization and computing resources able to meet ATLAS requirements of petabytes scale data operations. In this paper we present ATLAS Grid Information System (AGIS) designed to integrate configuration and status information about resources, services and topology of whole ATLAS Grid needed by ATLAS Distributed Computing applications and services.

Grid Integration Science, NREL Power Systems Engineering Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroposki, Benjamin

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.

Privacy protection in HealthGrid: distributing encryption management over the VO.

PubMed

Torres, Erik; de Alfonso, Carlos; Blanquer, Ignacio; Hernández, Vicente

2006-01-01

Grid technologies have proven to be very successful in tackling challenging problems in which data access and processing is a bottleneck. Notwithstanding the benefits that Grid technologies could have in Health applications, privacy leakages of current DataGrid technologies due to the sharing of data in VOs and the use of remote resources, compromise its widespreading. Privacy control for Grid technology has become a key requirement for the adoption of Grids in the Healthcare sector. Encrypted storage of confidential data effectively reduces the risk of disclosure. A self-enforcing scheme for encrypted data storage can be achieved by combining Grid security systems with distributed key management and classical cryptography techniques. Virtual Organizations, as the main unit of user management in Grid, can provide a way to organize key sharing, access control lists and secure encryption management. This paper provides programming models and discusses the value, costs and behavior of such a system implemented on top of one of the latest Grid middlewares. This work is partially funded by the Spanish Ministry of Science and Technology in the frame of the project Investigación y Desarrollo de Servicios GRID: Aplicación a Modelos Cliente-Servidor, Colaborativos y de Alta Productividad, with reference TIC2003-01318.

An Approach for Dynamic Grids

NASA Technical Reports Server (NTRS)

Slater, John W.; Liou, Meng-Sing; Hindman, Richard G.

1994-01-01

An approach is presented for the generation of two-dimensional, structured, dynamic grids. The grid motion may be due to the motion of the boundaries of the computational domain or to the adaptation of the grid to the transient, physical solution. A time-dependent grid is computed through the time integration of the grid speeds which are computed from a system of grid speed equations. The grid speed equations are derived from the time-differentiation of the grid equations so as to ensure that the dynamic grid maintains the desired qualities of the static grid. The grid equations are the Euler-Lagrange equations derived from a variational statement for the grid. The dynamic grid method is demonstrated for a model problem involving boundary motion, an inviscid flow in a converging-diverging nozzle during startup, and a viscous flow over a flat plate with an impinging shock wave. It is shown that the approach is more accurate for transient flows than an approach in which the grid speeds are computed using a finite difference with respect to time of the grid. However, the approach requires significantly more computational effort.

An algebraic homotopy method for generating quasi-three-dimensional grids for high-speed configurations

NASA Technical Reports Server (NTRS)

Moitra, Anutosh

1989-01-01

A fast and versatile procedure for algebraically generating boundary conforming computational grids for use with finite-volume Euler flow solvers is presented. A semi-analytic homotopic procedure is used to generate the grids. Grids generated in two-dimensional planes are stacked to produce quasi-three-dimensional grid systems. The body surface and outer boundary are described in terms of surface parameters. An interpolation scheme is used to blend between the body surface and the outer boundary in order to determine the field points. The method, albeit developed for analytically generated body geometries is equally applicable to other classes of geometries. The method can be used for both internal and external flow configurations, the only constraint being that the body geometries be specified in two-dimensional cross-sections stationed along the longitudinal axis of the configuration. Techniques for controlling various grid parameters, e.g., clustering and orthogonality are described. Techniques for treating problems arising in algebraic grid generation for geometries with sharp corners are addressed. A set of representative grid systems generated by this method is included. Results of flow computations using these grids are presented for validation of the effectiveness of the method.

A Preliminary Study of Building a Transmission Overlay for Regional US Power Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Yin; Li, Yalong; Liu, Yilu

2015-01-01

Many European countries have taken steps toward a Supergrid in order to transmit large amount of intermittent and remote renewable energy over long distance to load centers. In the US, as the expected increase in renewable generation and electricity demand, similar problem arises. A potential solution is to upgrade the transmission system at a higher voltage by constructing a new overlay grid. This paper will first address basic requirements for such an overlay grid. Potential transmission technologies will also be discussed. A multi-terminal VSC HVDC model is developed in DSATools to implement the overlay grid and a test case onmore » a regional NPCC system will be simulated. Another test system of entire US power grid, with three different interconnections tied together using back-to-back HVDC, is also introduced in this paper. Building an overlay system on top of this test case is ongoing, and will be discussed in future work.« less

Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

NASA Astrophysics Data System (ADS)

Cen, Zhaohui

2017-09-01

Gird-connected Photo-Voltaic (PV) systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model. Also, an overall power controller with Maximum Power Point Control (MPPT) is proposed to achieve both high-efficiency for solar energy harvesting and grid-connection stability. Finally, simulation results demonstrate the effectiveness of the PV system model and the proposed controller, and power quality issues are discussed.

Control and prediction for blackouts caused by frequency collapse in smart grids.

PubMed

Wang, Chengwei; Grebogi, Celso; Baptista, Murilo S

2016-09-01

The electric power system is one of the cornerstones of modern society. One of its most serious malfunctions is the blackout, a catastrophic event that may disrupt a substantial portion of the system, playing havoc to human life and causing great economic losses. Thus, understanding the mechanisms leading to blackouts and creating a reliable and resilient power grid has been a major issue, attracting the attention of scientists, engineers, and stakeholders. In this paper, we study the blackout problem in power grids by considering a practical phase-oscillator model. This model allows one to simultaneously consider different types of power sources (e.g., traditional AC power plants and renewable power sources connected by DC/AC inverters) and different types of loads (e.g., consumers connected to distribution networks and consumers directly connected to power plants). We propose two new control strategies based on our model, one for traditional power grids and another one for smart grids. The control strategies show the efficient function of the fast-response energy storage systems in preventing and predicting blackouts in smart grids. This work provides innovative ideas which help us to build up a robuster and more economic smart power system.

Grid Application Meta-Repository System: Repository Interconnectivity and Cross-domain Application Usage in Distributed Computing Environments

NASA Astrophysics Data System (ADS)

Tudose, Alexandru; Terstyansky, Gabor; Kacsuk, Peter; Winter, Stephen

Grid Application Repositories vary greatly in terms of access interface, security system, implementation technology, communication protocols and repository model. This diversity has become a significant limitation in terms of interoperability and inter-repository access. This paper presents the Grid Application Meta-Repository System (GAMRS) as a solution that offers better options for the management of Grid applications. GAMRS proposes a generic repository architecture, which allows any Grid Application Repository (GAR) to be connected to the system independent of their underlying technology. It also presents applications in a uniform manner and makes applications from all connected repositories visible to web search engines, OGSI/WSRF Grid Services and other OAI (Open Archive Initiative)-compliant repositories. GAMRS can also function as a repository in its own right and can store applications under a new repository model. With the help of this model, applications can be presented as embedded in virtual machines (VM) and therefore they can be run in their native environments and can easily be deployed on virtualized infrastructures allowing interoperability with new generation technologies such as cloud computing, application-on-demand, automatic service/application deployments and automatic VM generation.

Control and prediction for blackouts caused by frequency collapse in smart grids

NASA Astrophysics Data System (ADS)

Wang, Chengwei; Grebogi, Celso; Baptista, Murilo S.

2016-09-01

The electric power system is one of the cornerstones of modern society. One of its most serious malfunctions is the blackout, a catastrophic event that may disrupt a substantial portion of the system, playing havoc to human life and causing great economic losses. Thus, understanding the mechanisms leading to blackouts and creating a reliable and resilient power grid has been a major issue, attracting the attention of scientists, engineers, and stakeholders. In this paper, we study the blackout problem in power grids by considering a practical phase-oscillator model. This model allows one to simultaneously consider different types of power sources (e.g., traditional AC power plants and renewable power sources connected by DC/AC inverters) and different types of loads (e.g., consumers connected to distribution networks and consumers directly connected to power plants). We propose two new control strategies based on our model, one for traditional power grids and another one for smart grids. The control strategies show the efficient function of the fast-response energy storage systems in preventing and predicting blackouts in smart grids. This work provides innovative ideas which help us to build up a robuster and more economic smart power system.

Final Report for DOE Project: Portal Web Services: Support of DOE SciDAC Collaboratories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mary Thomas, PI; Geoffrey Fox, Co-PI; Gannon, D

2007-10-01

Grid portals provide the scientific community with familiar and simplified interfaces to the Grid and Grid services, and it is important to deploy grid portals onto the SciDAC grids and collaboratories. The goal of this project is the research, development and deployment of interoperable portal and web services that can be used on SciDAC National Collaboratory grids. This project has four primary task areas: development of portal systems; management of data collections; DOE science application integration; and development of web and grid services in support of the above activities.

Noniterative three-dimensional grid generation using parabolic partial differential equations

NASA Technical Reports Server (NTRS)

Edwards, T. A.

1985-01-01

A new algorithm for generating three-dimensional grids has been developed and implemented which numerically solves a parabolic partial differential equation (PDE). The solution procedure marches outward in two coordinate directions, and requires inversion of a scalar tridiagonal system in the third. Source terms have been introduced to control the spacing and angle of grid lines near the grid boundaries, and to control the outer boundary point distribution. The method has been found to generate grids about 100 times faster than comparable grids generated via solution of elliptic PDEs, and produces smooth grids for finite-difference flow calculations.

The data storage grid: the next generation of fault-tolerant storage for backup and disaster recovery of clinical images

NASA Astrophysics Data System (ADS)

King, Nelson E.; Liu, Brent; Zhou, Zheng; Documet, Jorge; Huang, H. K.

2005-04-01

Grid Computing represents the latest and most exciting technology to evolve from the familiar realm of parallel, peer-to-peer and client-server models that can address the problem of fault-tolerant storage for backup and recovery of clinical images. We have researched and developed a novel Data Grid testbed involving several federated PAC systems based on grid architecture. By integrating a grid computing architecture to the DICOM environment, a failed PACS archive can recover its image data from others in the federation in a timely and seamless fashion. The design reflects the five-layer architecture of grid computing: Fabric, Resource, Connectivity, Collective, and Application Layers. The testbed Data Grid architecture representing three federated PAC systems, the Fault-Tolerant PACS archive server at the Image Processing and Informatics Laboratory, Marina del Rey, the clinical PACS at Saint John's Health Center, Santa Monica, and the clinical PACS at the Healthcare Consultation Center II, USC Health Science Campus, will be presented. The successful demonstration of the Data Grid in the testbed will provide an understanding of the Data Grid concept in clinical image data backup as well as establishment of benchmarks for performance from future grid technology improvements and serve as a road map for expanded research into large enterprise and federation level data grids to guarantee 99.999 % up time.

Pyramid solar micro-grid

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Smarter Grid Solutions Demonstrates Smart Campus Power Control at NREL -

Science.gov Websites

Video Text Version | Energy Systems Integration Facility | NREL Smarter Grid Solutions Demonstrates Smart Campus Power Control at NREL - Video Text Version Smarter Grid Solutions Demonstrates Smart Campus Power Control at NREL - Video Text Version This is the text version for the Smarter Grid Solutions

NWTC's Grid Capabilities Providing Value for Partners | News | NREL

Science.gov Websites

controlled grid conditions where you can research interactions of grid impacts and resource variability impacts on the system at the same time." This capability creates an unrivaled asset. "That's on a smaller 2.5-megawatt dynamometer. They started to realize that grid impacts also need to be

Application of advanced grid generation techniques for flow field computations about complex configurations

NASA Technical Reports Server (NTRS)

Kathong, Monchai; Tiwari, Surendra N.

1988-01-01

In the computation of flowfields about complex configurations, it is very difficult to construct a boundary-fitted coordinate system. An alternative approach is to use several grids at once, each of which is generated independently. This procedure is called the multiple grids or zonal grids approach; its applications are investigated. The method conservative providing conservation of fluxes at grid interfaces. The Euler equations are solved numerically on such grids for various configurations. The numerical scheme used is the finite-volume technique with a three-stage Runge-Kutta time integration. The code is vectorized and programmed to run on the CDC VPS-32 computer. Steady state solutions of the Euler equations are presented and discussed. The solutions include: low speed flow over a sphere, high speed flow over a slender body, supersonic flow through a duct, and supersonic internal/external flow interaction for an aircraft configuration at various angles of attack. The results demonstrate that the multiple grids approach along with the conservative interfacing is capable of computing the flows about the complex configurations where the use of a single grid system is not possible.

Grid point extraction and coding for structured light system

NASA Astrophysics Data System (ADS)

Song, Zhan; Chung, Ronald

2011-09-01

A structured light system simplifies three-dimensional reconstruction by illuminating a specially designed pattern to the target object, thereby generating a distinct texture on it for imaging and further processing. Success of the system hinges upon what features are to be coded in the projected pattern, extracted in the captured image, and matched between the projector's display panel and the camera's image plane. The codes have to be such that they are largely preserved in the image data upon illumination from the projector, reflection from the target object, and projective distortion in the imaging process. The features also need to be reliably extracted in the image domain. In this article, a two-dimensional pseudorandom pattern consisting of rhombic color elements is proposed, and the grid points between the pattern elements are chosen as the feature points. We describe how a type classification of the grid points plus the pseudorandomness of the projected pattern can equip each grid point with a unique label that is preserved in the captured image. We also present a grid point detector that extracts the grid points without the need of segmenting the pattern elements, and that localizes the grid points in subpixel accuracy. Extensive experiments are presented to illustrate that, with the proposed pattern feature definition and feature detector, more features points in higher accuracy can be reconstructed in comparison with the existing pseudorandomly encoded structured light systems.

Real time hardware implementation of power converters for grid integration of distributed generation and STATCOM systems

NASA Astrophysics Data System (ADS)

Jaithwa, Ishan

Deployment of smart grid technologies is accelerating. Smart grid enables bidirectional flows of energy and energy-related communications. The future electricity grid will look very different from today's power system. Large variable renewable energy sources will provide a greater portion of electricity, small DERs and energy storage systems will become more common, and utilities will operate many different kinds of energy efficiency. All of these changes will add complexity to the grid and require operators to be able to respond to fast dynamic changes to maintain system stability and security. This thesis investigates advanced control technology for grid integration of renewable energy sources and STATCOM systems by verifying them on real time hardware experiments using two different systems: d SPACE and OPAL RT. Three controls: conventional, direct vector control and the intelligent Neural network control were first simulated using Matlab to check the stability and safety of the system and were then implemented on real time hardware using the d SPACE and OPAL RT systems. The thesis then shows how dynamic-programming (DP) methods employed to train the neural networks are better than any other controllers where, an optimal control strategy is developed to ensure effective power delivery and to improve system stability. Through real time hardware implementation it is proved that the neural vector control approach produces the fastest response time, low overshoot, and, the best performance compared to the conventional standard vector control method and DCC vector control technique. Finally the entrepreneurial approach taken to drive the technologies from the lab to market via ORANGE ELECTRIC is discussed in brief.

Smart Grid Development: Multinational Demo Project Analysis

NASA Astrophysics Data System (ADS)

Oleinikova, I.; Mutule, A.; Obushevs, A.; Antoskovs, N.

2016-12-01

This paper analyses demand side management (DSM) projects and stakeholders' experience with the aim to develop, promote and adapt smart grid tehnologies in Latvia. The research aims at identifying possible system service posibilites, including demand response (DR) and determining the appropriate market design for such type of services to be implemented at the Baltic power system level, with the cooperation of distribution system operator (DSO) and transmission system operator (TSO). This paper is prepared as an extract from the global smart grid best practices, smart solutions and business models.

Distribution Management System Volt/VAR Evaluation | Grid Modernization |

Science.gov Websites

NREL Distribution Management System Volt/VAR Evaluation Distribution Management System Volt/VAR Evaluation This project involves building a prototype distribution management system testbed that links a GE Grid Solutions distribution management system to power hardware-in-the-loop testing. This setup is

ESIF 2016: Modernizing Our Grid and Energy System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Becelaere, Kimberly

This 2016 annual report highlights work conducted at the Energy Systems Integration Facility (ESIF) in FY 2016, including grid modernization, high-performance computing and visualization, and INTEGRATE projects.

Ion extraction capabilities of two-grid accelerator systems. [for spacecraft propulsion

NASA Technical Reports Server (NTRS)

Rovang, D. C.; Wilbur, P. J.

1984-01-01

An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. A large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current is presented. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high.

Advanced Platform for Development and Evaluation of Grid Interconnection Systems Using Hardware-in-the-Loop: Part III -- Grid Interconnection System Evaluator: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundstrom, B.; Shirazi, M.; Coddington, M.

2013-01-01

This paper, presented at the IEEE Green Technologies Conference 2013, describes a Grid Interconnection System Evaluator (GISE) that leverages hardware-in-the-loop (HIL) simulation techniques to rapidly evaluate the grid interconnection standard conformance of an ICS according to the procedures in IEEE Std 1547.1 (TM). The architecture and test sequencing of this evaluation tool, along with a set of representative ICS test results from three different photovoltaic (PV) inverters, are presented. The GISE adds to the National Renewable Energy Laboratory's (NREL) evaluation platform that now allows for rapid development of ICS control algorithms using controller HIL (CHIL) techniques, the ability to testmore » the dc input characteristics of PV-based ICSs through the use of a PV simulator capable of simulating real-world dynamics using power HIL (PHIL), and evaluation of ICS grid interconnection conformance.« less

Advanced Platform for Development and Evaluation of Grid Interconnection Systems Using Hardware-in-the-Loop: Part III - Grid Interconnection System Evaluator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundstrom, B.; Shirazi, M.; Coddington, M.

2013-01-01

This paper describes a Grid Interconnection System Evaluator (GISE) that leverages hardware-in-the-loop (HIL) simulation techniques to rapidly evaluate the grid interconnection standard conformance of an ICS according to the procedures in IEEE Std 1547.1. The architecture and test sequencing of this evaluation tool, along with a set of representative ICS test results from three different photovoltaic (PV) inverters, are presented. The GISE adds to the National Renewable Energy Laboratory's (NREL) evaluation platform that now allows for rapid development of ICS control algorithms using controller HIL (CHIL) techniques, the ability to test the dc input characteristics of PV-based ICSs through themore » use of a PV simulator capable of simulating real-world dynamics using power HIL (PHIL), and evaluation of ICS grid interconnection conformance.« less

Interplay Between Energy-Market Dynamics and Physical Stability of a Smart Power Grid

NASA Astrophysics Data System (ADS)

Picozzi, Sergio; Mammoli, Andrea; Sorrentino, Francesco

2013-03-01

A smart power grid is being envisioned for the future which, among other features, should enable users to play the dual role of consumers as well as producers and traders of energy, thanks to emerging renewable energy production and energy storage technologies. As a complex dynamical system, any power grid is subject to physical instabilities. With existing grids, such instabilities tend to be caused by natural disasters, human errors, or weather-related peaks in demand. In this work we analyze the impact, upon the stability of a smart grid, of the energy-market dynamics arising from users' ability to buy from and sell energy to other users. The stability analysis of the resulting dynamical system is performed assuming different proposed models for this market of the future, and the corresponding stability regions in parameter space are identified. We test our theoretical findings by comparing them with data collected from some existing prototype systems.

First Steps in the Smart Grid Framework: An Optimal and Feasible Pathway Toward Power System Reform in Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bracho, Riccardo; Linvill, Carl; Sedano, Richard

With the vision to transform the power sector, Mexico included in the new laws and regulations deployment of smart grid technologies and provided various attributes to the Ministry of Energy and the Energy Regulatory Commission to enact public policies and regulation. The use of smart grid technologies can have a significant impact on the integration of variable renewable energy resources while maintaining reliability and stability of the system, significantly reducing technical and non-technical electricity losses in the grid, improving cyber security, and allowing consumers to make distributed generation and demand response decisions. This report describes for Mexico's Ministry of Energymore » (SENER) an overall approach (Optimal Feasible Pathway) for moving forward with smart grid policy development in Mexico to enable increasing electric generation from renewable energy in a way that optimizes system stability and reliability in an efficient and cost-effective manner.« less

A Taxonomy on Accountability and Privacy Issues in Smart Grids

NASA Astrophysics Data System (ADS)

Naik, Ameya; Shahnasser, Hamid

2017-07-01

Cyber-Physical Systems (CPS) are combinations of computation, networking, and physical processes. Embedded computers and networks monitor control the physical processes, which affect computations and vice versa. Two applications of cyber physical systems include health-care and smart grid. In this paper, we have considered privacy aspects of cyber-physical system applicable to smart grid. Smart grid in collaboration with different stockholders can help in the improvement of power generation, communication, circulation and consumption. The proper management with monitoring feature by customers and utility of energy usage can be done through proper transmission and electricity flow; however cyber vulnerability could be increased due to an increased assimilation and linkage. This paper discusses various frameworks and architectures proposed for achieving accountability in smart grids by addressing privacy issues in Advance Metering Infrastructure (AMI). This paper also highlights additional work needed for accountability in more precise specifications such as uncertainty or ambiguity, indistinct, unmanageability, and undetectably.

Unlocking the potential of smart grid technologies with behavioral science

PubMed Central

Sintov, Nicole D.; Schultz, P. Wesley

2015-01-01

Smart grid systems aim to provide a more stable and adaptable electricity infrastructure, and to maximize energy efficiency. Grid-linked technologies vary widely in form and function, but generally share common potentials: to reduce energy consumption via efficiency and/or curtailment, to shift use to off-peak times of day, and to enable distributed storage and generation options. Although end users are central players in these systems, they are sometimes not central considerations in technology or program design, and in some cases, their motivations for participating in such systems are not fully appreciated. Behavioral science can be instrumental in engaging end-users and maximizing the impact of smart grid technologies. In this paper, we present emerging technologies made possible by a smart grid infrastructure, and for each we highlight ways in which behavioral science can be applied to enhance their impact on energy savings. PMID:25914666

Security and Stability Analysis of Wind Farms Integration into Distribution Network

NASA Astrophysics Data System (ADS)

Guan-yang, Li; Hongzhao, Wang; Guanglei, Li; Yamei, Cheng; Hong-zheng, Liu; Yi, Sun

2017-05-01

With the increasing share of the wind power in the power system, wind power fluctuations will cause obvious negative impacts on weak local grid. This paper firstly establish electromechanical transient simulation model for doubly fed induction wind turbine, then use Matlab/Simulink to achieve power flow calculation and transient simulation of power system including wind farms, the local synchronous generator, load, etc, finally analyze wind power on the impact of the local power grid under typical circumstances. The actual calculated results indicate that wind mutation causes little effect on the power grid, but when the three-phase short circuit fault happens, active power of wind power decreases sharply and the voltage of location of wind power into the grid also drop sharply, finally wind farm split from power system. This situation is not conducive to security and stability of the local power grid. It is necessary to develop security and stability measures in the future.

Unlocking the potential of smart grid technologies with behavioral science.

PubMed

Sintov, Nicole D; Schultz, P Wesley

2015-01-01

Smart grid systems aim to provide a more stable and adaptable electricity infrastructure, and to maximize energy efficiency. Grid-linked technologies vary widely in form and function, but generally share common potentials: to reduce energy consumption via efficiency and/or curtailment, to shift use to off-peak times of day, and to enable distributed storage and generation options. Although end users are central players in these systems, they are sometimes not central considerations in technology or program design, and in some cases, their motivations for participating in such systems are not fully appreciated. Behavioral science can be instrumental in engaging end-users and maximizing the impact of smart grid technologies. In this paper, we present emerging technologies made possible by a smart grid infrastructure, and for each we highlight ways in which behavioral science can be applied to enhance their impact on energy savings.

A techno-economic assessment of grid connected photovoltaic system for hospital building in Malaysia

NASA Astrophysics Data System (ADS)

Mat Isa, Normazlina; Tan, Chee Wei; Yatim, AHM

2017-07-01

Conventionally, electricity in hospital building are supplied by the utility grid which uses mix fuel including coal and gas. Due to enhancement in renewable technology, many building shall moving forward to install their own PV panel along with the grid to employ the advantages of the renewable energy. This paper present an analysis of grid connected photovoltaic (GCPV) system for hospital building in Malaysia. A discussion is emphasized on the economic analysis based on Levelized Cost of Energy (LCOE) and total Net Present Post (TNPC) in regards with the annual interest rate. The analysis is performed using Hybrid Optimization Model for Electric Renewables (HOMER) software which give optimization and sensitivity analysis result. An optimization result followed by the sensitivity analysis also being discuss in this article thus the impact of the grid connected PV system has be evaluated. In addition, the benefit from Net Metering (NeM) mechanism also discussed.

Unlocking the potential of smart grid technologies with behavioral science

DOE PAGES

Sintov, Nicole D.; Schultz, P. Wesley

2015-04-09

Smart grid systems aim to provide a more stable and adaptable electricity infrastructure, and to maximize energy efficiency. Grid-linked technologies vary widely in form and function, but generally share common potentials: to reduce energy consumption via efficiency and/or curtailment, to shift use to off-peak times of day, and to enable distributed storage and generation options. Although end users are central players in these systems, they are sometimes not central considerations in technology or program design, and in some cases, their motivations for participating in such systems are not fully appreciated. Behavioral science can be instrumental in engaging end-users and maximizingmore » the impact of smart grid technologies. In this study, we present emerging technologies made possible by a smart grid infrastructure, and for each we highlight ways in which behavioral science can be applied to enhance their impact on energy savings.« less

Unlocking the potential of smart grid technologies with behavioral science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sintov, Nicole D.; Schultz, P. Wesley

Smart grid systems aim to provide a more stable and adaptable electricity infrastructure, and to maximize energy efficiency. Grid-linked technologies vary widely in form and function, but generally share common potentials: to reduce energy consumption via efficiency and/or curtailment, to shift use to off-peak times of day, and to enable distributed storage and generation options. Although end users are central players in these systems, they are sometimes not central considerations in technology or program design, and in some cases, their motivations for participating in such systems are not fully appreciated. Behavioral science can be instrumental in engaging end-users and maximizingmore » the impact of smart grid technologies. In this study, we present emerging technologies made possible by a smart grid infrastructure, and for each we highlight ways in which behavioral science can be applied to enhance their impact on energy savings.« less

Maximum capacity model of grid-connected multi-wind farms considering static security constraints in electrical grids

NASA Astrophysics Data System (ADS)

Zhou, W.; Qiu, G. Y.; Oodo, S. O.; He, H.

2013-03-01

An increasing interest in wind energy and the advance of related technologies have increased the connection of wind power generation into electrical grids. This paper proposes an optimization model for determining the maximum capacity of wind farms in a power system. In this model, generator power output limits, voltage limits and thermal limits of branches in the grid system were considered in order to limit the steady-state security influence of wind generators on the power system. The optimization model was solved by a nonlinear primal-dual interior-point method. An IEEE-30 bus system with two wind farms was tested through simulation studies, plus an analysis conducted to verify the effectiveness of the proposed model. The results indicated that the model is efficient and reasonable.

Atomic and Molecular Spectroscopic Studies of the DIII-D Neutral Beam Ion Source and Neutralizer

NASA Astrophysics Data System (ADS)

Crowley, B.; Rauch, J.; Scoville, J. T.; Sharma, S. K.; Choksi, B.

2015-11-01

The neutral beam system is interesting in that it comprises two distinct low temperature plasmas. Firstly, the ion source is typically a filament or RF driven plasma from which ions are extracted by a high voltage accelerator grid system. Secondly the neutralizer is essentially a low temperature plasma system with the beam serving as the primary ionization source and the neutralizer walls serving as conducting boundaries. Atomic spectroscopy of Doppler shifted D-alpha light emanating from the fast atoms is studied to determine the composition of the source and the divergence of the beam. Molecular spectroscopy involves measuring fine structure in electron-vibrational rotational bands. The technique has applications in low temperature plasmas and here it is used to determine gas temperature in the neutralizer. We describe the experimental set-up and the physics model used to relate the spectroscopic data to the plasma parameters and we present results of recent experiments exploring how to increase neutralization efficiency. Supported by the US DOE under DE-FC02-04ER54698.

Dynamic analysis of combined photovoltaic source and synchronous generator connected to power grid

NASA Astrophysics Data System (ADS)

Mahabal, Divya

In the world of expanding economy and technology, the energy demand is likely to increase even with the global efforts of saving and increasing energy efficiency. Higher oil prices, effects of greenhouse gases, and concerns over other environmental impacts gave way to Distributed Generation (DG). With adequate awareness and support, DG's can meet these rising energy demands at lower prices compared to conventional methods. Extensive research is taking place in different areas like fuel cells, photovoltaic cells, wind turbines, and gas turbines. DG's when connected to a grid increase the overall efficiency of the power grid. It is believed that three-fifth of the world's electricity would account for renewable energy by middle of 21st century. This thesis presents the dynamic analysis of a grid connected photovoltaic (PV) system and synchronous generator. A grid is considered as an infinite bus. The photovol-taic system and synchronous generator act as small scale distributed energy resources. The output of the photovoltaic system depends on the light intensity, temperature, and irradiance levels of sun. The maximum power point tracking and DC/AC converter are also modeled for the photovoltaic system. The PV system is connected to the grid through DC/AC system. Different combinations of PV and synchronous generator are modeled with the grid to study the dynamics of the proposed system. The dynamics of the test system is analyzed by subjecting the system to several disturbances under various conditions. All modules are individually modeled and con-nected using MATLAB/Simulink software package. Results from the study show that, as the penetration of renewable energy sources like PV increases into the power system, the dynamics of the system becomes faster. When considering cases such as load switching, PV cannot deliver more power as the performance of PV depends on environmental conditions. Synchronous generator in power system can produce the required amount of power. As the main aim of this research is to use renewable sources like PV in the system, it is advantageous to use a combination of both PV and synchronous generator in the system.

Coaxial charged particle energy analyzer

NASA Technical Reports Server (NTRS)

Kelly, Michael A. (Inventor); Bryson, III, Charles E. (Inventor); Wu, Warren (Inventor)

2011-01-01

A non-dispersive electrostatic energy analyzer for electrons and other charged particles having a generally coaxial structure of a sequentially arranged sections of an electrostatic lens to focus the beam through an iris and preferably including an ellipsoidally shaped input grid for collimating a wide acceptance beam from a charged-particle source, an electrostatic high-pass filter including a planar exit grid, and an electrostatic low-pass filter. The low-pass filter is configured to reflect low-energy particles back towards a charged particle detector located within the low-pass filter. Each section comprises multiple tubular or conical electrodes arranged about the central axis. The voltages on the lens are scanned to place a selected energy band of the accepted beam at a selected energy at the iris. Voltages on the high-pass and low-pass filters remain substantially fixed during the scan.

Variability of Wind Speeds and Power over Europe

NASA Astrophysics Data System (ADS)

Tambke, J.; von Bremen, L.; de Decker, J.; Schmidt, M.; Steinfeld, G.; Wolff, J.-O.

2010-09-01

This study comprises two parts: First, we describe the vertical wind speed and turbulence profiles that result from our improved PBL scheme and compare it to observations and 1-dimensional approaches (Monin-Obukhov etc.). Second, we analyse the spatio-temporal correlations in our meso-scale simulations for the years 2004 to 2007 over entire Europe, with special focus on the Irish, North and Baltic Sea. 1.) Vertical Wind Speed Profiles The vertical wind profile above the sea has to be modelled with high accuracy for tip heights up to 160m in order to achieve precise wind resource assessments, to calculate loads and wakes of wind turbines as well as for reliable short-term wind power forecasts. We present an assessment of different models for wind profiles in unstable, neutral and stable thermal stratification. The meso-scale models comprise MM5, WRF and COSMO-EU (LME). Both COSMO-EU from the German Weather Service DWD and WRF use a turbulence closure of 2.5th order - and lead to similar results. Especially the limiting effect of low boundary layer heights on the wind shear in very stable stratification is well captured. In our new WRF-formulation for the mixing length in the Mellor-Yamada-Janjic (MYJ) parameterisation of the Planetary Boundary Layer (PBL-scheme), the master length scale itself depends on the Monin-Obukhov-Length as a parameter for the heat flux effects on the turbulent mixing. This new PBL-scheme shows a better performance for all weather conditions than the original MYJ-scheme. Apart from the low-boundary-layer-effect in very stable situations (which are seldom), standard Monin-Obukhov formulations in combination with the Charnock relation for the sea surface roughness show good agreement with the FINO1-data (German Bight). Interesting results were achieved with two more detailed micro-scale approaches: - the parameterization proposed by Pena, Gryning and Hasager [BLM 2008] that depends on the boundary layer height - our ICWP-model, were the flux of momentum through the air-sea interface is described by a common wave boundary layer with enhanced Charnock dynamics. 2.) Wind Field Variability Time series of wind speed and power from 400 potential offshore locations and 16,000 onshore sites in the 2020 and 2030 scenarios are part of the design basis of the EU-project www.OffshoreGrid.eu. This project investigates the grid integration of all planned offshore farms in Northern Europe and will serve as the basis for the "Blueprint for Offshore Grids" by the European Commission. The synchronous wind time series were calculated with the WRF-model. The simulation comprises four years and was validated with a number of wind measurements. We present detailed statistics of local, clustered and regional power production. The analysis quantifies spatial and temporal correlations, extreme events and ramps. Important results are the smoothing effects in a pan-European offshore grid. Key words: Offshore Wind Resource Assessment; Marine Meteorology; Wind Speed Profile; Marine Atmospheric Boundary Layer; Wind Variability, Spatio-temporal Correlation; Electricity Grid Integration

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

NASA Astrophysics Data System (ADS)

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 power. The scope of this work is to • develop a mathematical model for a salient pole, 2 damper winding synchronous generator with d axis saturation suitable for transient analysis, • develop a mathematical model for a voltage regulator and excitation system using the IEEE AC8B voltage regulator and excitation system template, • develop mathematical models for an energy storage primary control system, LC filter and transformer suitable for transient analysis, • combine the generator and energy storage models in a micro-grid context, • develop mathematical models for electric system components in the stationary abc frame and rotating dq reference frame, • develop a secondary control network for dispatch of micro-grid assets, • establish micro-grid limits of stable operation for step changes in load and power commands based on simulations of model data assuming net load on the micro-grid, and • use generator and electric system models to assess the generator current magnitude during phase-to-ground faults.

Bridges and Ladders: Building the Logic and Structure for Cyberspace

DTIC Science & Technology

2012-06-01

control model defends and attacks from the GIG . By comparing and contrasting the three models, the author makes a recommendation for a hybrid model to...operations in cyberspace. The directive was clear in its direction for USCYBERCOM, through USSTRATCOM, to secure the DoD global information grid ( GIG ) and...capabilities and potential breakthroughs. The GIG is comprised of 7 million devices spread across 15,000 networks that are attacked “hundreds of

Low temperature sulfur and sodium metal battery for grid-scale energy storage application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Gao; Wang, Dongdong

A re-chargeable battery comprising a non-dendrite forming sodium (Na)/potassium (K) liquid metal alloy anode, a sulfur and polyacrylonitrile (PAN) conductive polymer composite cathode, a polyethyleneoxide (PEO) solid electrolyte, a solid electrolyte interface (SEI) formed on the PEO solid electrolyte; and a cell housing, wherein the anode, cathode, and electrolyte are assembled into the cell housing with the PEO solid electrolyte disposed between the cathode and anode.

DIRAC3 - the new generation of the LHCb grid software

NASA Astrophysics Data System (ADS)

Tsaregorodtsev, A.; Brook, N.; Casajus Ramo, A.; Charpentier, Ph; Closier, J.; Cowan, G.; Graciani Diaz, R.; Lanciotti, E.; Mathe, Z.; Nandakumar, R.; Paterson, S.; Romanovsky, V.; Santinelli, R.; Sapunov, M.; Smith, A. C.; Seco Miguelez, M.; Zhelezov, A.

2010-04-01

DIRAC, the LHCb community Grid solution, was considerably reengineered in order to meet all the requirements for processing the data coming from the LHCb experiment. It is covering all the tasks starting with raw data transportation from the experiment area to the grid storage, data processing up to the final user analysis. The reengineered DIRAC3 version of the system includes a fully grid security compliant framework for building service oriented distributed systems; complete Pilot Job framework for creating efficient workload management systems; several subsystems to manage high level operations like data production and distribution management. The user interfaces of the DIRAC3 system providing rich command line and scripting tools are complemented by a full-featured Web portal providing users with a secure access to all the details of the system status and ongoing activities. We will present an overview of the DIRAC3 architecture, new innovative features and the achieved performance. Extending DIRAC3 to manage computing resources beyond the WLCG grid will be discussed. Experience with using DIRAC3 by other user communities than LHCb and in other application domains than High Energy Physics will be shown to demonstrate the general-purpose nature of the system.

Turbulence generation through intense kinetic energy sources

NASA Astrophysics Data System (ADS)

Maqui, Agustin F.; Donzis, Diego A.

2016-06-01

Direct numerical simulations (DNS) are used to systematically study the development and establishment of turbulence when the flow is initialized with concentrated regions of intense kinetic energy. This resembles both active and passive grids which have been extensively used to generate and study turbulence in laboratories at different Reynolds numbers and with different characteristics, such as the degree of isotropy and homogeneity. A large DNS database was generated covering a wide range of initial conditions with a focus on perturbations with some directional preference, a condition found in active jet grids and passive grids passed through a contraction as well as a new type of active grid inspired by the experimental use of lasers to photo-excite the molecules that comprise the fluid. The DNS database is used to assert under what conditions the flow becomes turbulent and if so, the time required for this to occur. We identify a natural time scale of the problem which indicates the onset of turbulence and a single Reynolds number based exclusively on initial conditions which controls the evolution of the flow. It is found that a minimum Reynolds number is needed for the flow to evolve towards fully developed turbulence. An extensive analysis of single and two point statistics, velocity as well as spectral dynamics and anisotropy measures is presented to characterize the evolution of the flow towards realistic turbulence.

The research of the malfunction diagnosis and predictions system in the smart electric grid

NASA Astrophysics Data System (ADS)

Wang, Yaqing; Zhang, Guoxing; Xu, Hongbing

2017-03-01

The Chinese smart electric grid constriction has been increasing with the technology development. However, the monitoring equipment and background system which should play important roles did not work as intended and restrict to the efficacy of the smart grid. In this essay, it has researched an intelligentized malfunction diagnosis and predictions system which could work with the existed monitoring equipment to function as whole energy monitoring, common malfunction diagnosis, faulted proactive judgment and automatically elimination.

Using Computing and Data Grids for Large-Scale Science and Engineering

NASA Technical Reports Server (NTRS)

Johnston, William E.

2001-01-01

We use the term "Grid" to refer to a software system that provides uniform and location independent access to geographically and organizationally dispersed, heterogeneous resources that are persistent and supported. These emerging data and computing Grids promise to provide a highly capable and scalable environment for addressing large-scale science problems. We describe the requirements for science Grids, the resulting services and architecture of NASA's Information Power Grid (IPG) and DOE's Science Grid, and some of the scaling issues that have come up in their implementation.

TIGER: A graphically interactive grid system for turbomachinery applications

NASA Technical Reports Server (NTRS)

Shih, Ming-Hsin; Soni, Bharat K.

1992-01-01

Numerical grid generation algorithm associated with the flow field about turbomachinery geometries is presented. Graphical user interface is developed with FORMS Library to create an interactive, user-friendly working environment. This customized algorithm reduces the man-hours required to generate a grid associated with turbomachinery geometry, as compared to the use of general-purpose grid generation softwares. Bezier curves are utilized both interactively and automatically to accomplish grid line smoothness and orthogonality. Graphical User Interactions are provided in the algorithm, allowing the user to design and manipulate the grid lines with a mouse.

New Boundary Constraints for Elliptic Systems used in Grid Generation Problems

NASA Technical Reports Server (NTRS)

Kaul, Upender K.; Clancy, Daniel (Technical Monitor)

2002-01-01

This paper discusses new boundary constraints for elliptic partial differential equations as used in grid generation problems in generalized curvilinear coordinate systems. These constraints, based on the principle of local conservation of thermal energy in the vicinity of the boundaries, are derived using the Green's Theorem. They uniquely determine the so called decay parameters in the source terms of these elliptic systems. These constraints' are designed for boundary clustered grids where large gradients in physical quantities need to be resolved adequately. It is observed that the present formulation also works satisfactorily for mild clustering. Therefore, a closure for the decay parameter specification for elliptic grid generation problems has been provided resulting in a fully automated elliptic grid generation technique. Thus, there is no need for a parametric study of these decay parameters since the new constraints fix them uniquely. It is also shown that for Neumann type boundary conditions, these boundary constraints uniquely determine the solution to the internal elliptic problem thus eliminating the non-uniqueness of the solution of an internal Neumann boundary value grid generation problem.

The implementation of an aeronautical CFD flow code onto distributed memory parallel systems

NASA Astrophysics Data System (ADS)

Ierotheou, C. S.; Forsey, C. R.; Leatham, M.

2000-04-01

The parallelization of an industrially important in-house computational fluid dynamics (CFD) code for calculating the airflow over complex aircraft configurations using the Euler or Navier-Stokes equations is presented. The code discussed is the flow solver module of the SAUNA CFD suite. This suite uses a novel grid system that may include block-structured hexahedral or pyramidal grids, unstructured tetrahedral grids or a hybrid combination of both. To assist in the rapid convergence to a solution, a number of convergence acceleration techniques are employed including implicit residual smoothing and a multigrid full approximation storage scheme (FAS). Key features of the parallelization approach are the use of domain decomposition and encapsulated message passing to enable the execution in parallel using a single programme multiple data (SPMD) paradigm. In the case where a hybrid grid is used, a unified grid partitioning scheme is employed to define the decomposition of the mesh. The parallel code has been tested using both structured and hybrid grids on a number of different distributed memory parallel systems and is now routinely used to perform industrial scale aeronautical simulations. Copyright

Designing Wind and Solar Power Purchase Agreements to Support Grid Integration

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Neill, Barbara; Chernyakhovskiy, Ilya

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.

Energy Systems Integration Facility Videos | Energy Systems Integration

Science.gov Websites

Facility | NREL Energy Systems Integration Facility Videos Energy Systems Integration Facility Integration Facility NREL + SolarCity: Maximizing Solar Power on Electrical Grids Redefining What's Possible for Renewable Energy: Grid Integration Robot-Powered Reliability Testing at NREL's ESIF Microgrid

A Community Terrain-Following Ocean Modeling System (ROMS/TOMS)

DTIC Science & Technology

2012-09-30

next user workshop will be held in Rio de Janeiro , Brazil, October 22-24, 2012. A special fourth day (October 25) has been added to focus modern...grid_extract.m is used to extract the Delaware Bay refinement grid (58 x 142) and Delaware River composite grid (42 x 55). Similarly, grid_extract.m is

Grid related issues for static and dynamic geometry problems using systems of overset structured grids

NASA Technical Reports Server (NTRS)

Meakin, Robert L.

1995-01-01

Grid related issues of the Chimera overset grid method are discussed in the context of a method of solution and analysis of unsteady three-dimensional viscous flows. The state of maturity of the various pieces of support software required to use the approach is considered. Current limitations of the approach are identified.

Performance evaluation of a 2-mode PV grid connected system in Thailand -- Case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jivacate, C.; Mongconvorawan, S.; Sinratanapukdee, E.

A PV grid connected system with small battery bank has been set up in a rural district, North Thailand in order to demonstrate a 2-mode operation concept. The objective is to gain experience on the PV grid connected concept without battery storage. However, due to the evening peak demand and a rather weak distribution grid which is typical in rural areas, small battery bank is still required to enable the maximum energy transfer to grid for the time being before moving fully to the no battery mode. The analyzed data seems to indicate possible performance improvement by re-arranging the numbermore » of PV modules and battery in the string.« less

GRAPEVINE: Grids about anything by Poisson's equation in a visually interactive networking environment

NASA Technical Reports Server (NTRS)

Sorenson, Reese L.; Mccann, Karen

1992-01-01

A proven 3-D multiple-block elliptic grid generator, designed to run in 'batch mode' on a supercomputer, is improved by the creation of a modern graphical user interface (GUI) running on a workstation. The two parts are connected in real time by a network. The resultant system offers a significant speedup in the process of preparing and formatting input data and the ability to watch the grid solution converge by replotting the grid at each iteration step. The result is a reduction in user time and CPU time required to generate the grid and an enhanced understanding of the elliptic solution process. This software system, called GRAPEVINE, is described, and certain observations are made concerning the creation of such software.

Microgrid Controllers : Expanding Their Role and Evaluating Their Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maitra, Arindam; Pratt, Annabelle; Hubert, Tanguy

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

Contribution of concentrator photovoltaic installations to grid stability and power quality

NASA Astrophysics Data System (ADS)

del Toro García, Xavier; Roncero-Sánchez, Pedro; Torres, Alfonso Parreño; Vázquez, Javier

2012-10-01

Large-scale integration of Photovoltaic (PV) generation systems, including Concentrator Photovoltaic (CPV) technologies, will require the contribution and support of these technologies to the management and stability of the grid. New regulations and grid codes for PV installations in countries such as Spain have recently included dynamic voltage control support during faults. The PV installation must stay connected to the grid during voltage dips and inject reactive power in order to enhance the stability of the system. The existing PV inverter technologies based on the Voltage-Source Converter (VSC) are in general well suited to provide advanced grid-support characteristics. Nevertheless, new advanced control schemes and monitoring techniques will be necessary to meet the most demanding requirements.

Onboard power line conditioning system for an electric or hybrid vehicle

DOEpatents

Kajouke, Lateef A.; Perisic, Milun

2016-06-14

A power line quality conditioning system for a vehicle includes an onboard rechargeable direct current (DC) energy storage system and an onboard electrical system coupled to the energy storage system. The energy storage system provides DC energy to drive an electric traction motor of the vehicle. The electrical system operates in a charging mode such that alternating current (AC) energy from a power grid external to the vehicle is converted to DC energy to charge the DC energy storage system. The electrical system also operates in a vehicle-to-grid power conditioning mode such that DC energy from the DC energy storage system is converted to AC energy to condition an AC voltage of the power grid.

Optimized design and control of an off grid solar PV/hydrogen fuel cell power system for green buildings

NASA Astrophysics Data System (ADS)

Ghenai, C.; Bettayeb, M.

2017-11-01

Modelling, simulation, optimization and control strategies are used in this study to design a stand-alone solar PV/Fuel Cell/Battery/Generator hybrid power system to serve the electrical load of a commercial building. The main objective is to design an off grid energy system to meet the desired electric load of the commercial building with high renewable fraction, low emissions and low cost of energy. The goal is to manage the energy consumption of the building, reduce the associate cost and to switch from grid-tied fossil fuel power system to an off grid renewable and cleaner power system. Energy audit was performed in this study to determine the energy consumption of the building. Hourly simulations, modelling and optimization were performed to determine the performance and cost of the hybrid power configurations using different control strategies. The results show that the hybrid off grid solar PV/Fuel Cell/Generator/Battery/Inverter power system offers the best performance for the tested system architectures. From the total energy generated from the off grid hybrid power system, 73% is produced from the solar PV, 24% from the fuel cell and 3% from the backup Diesel generator. The produced power is used to meet all the AC load of the building without power shortage (<0.1%). The hybrid power system produces 18.2% excess power that can be used to serve the thermal load of the building. The proposed hybrid power system is sustainable, economically viable and environmentally friendly: High renewable fraction (66.1%), low levelized cost of energy (92 /MWh), and low carbon dioxide emissions (24 kg CO2/MWh) are achieved.

Smart Grid Status and Metrics Report Appendices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balducci, Patrick J.; Antonopoulos, Chrissi A.; Clements, Samuel L.

A smart grid uses digital power control and communication technology to improve the reliability, security, flexibility, and efficiency of the electric system, from large generation through the delivery systems to electricity consumers and a growing number of distributed generation and storage resources. To convey progress made in achieving the vision of a smart grid, this report uses a set of six characteristics derived from the National Energy Technology Laboratory Modern Grid Strategy. The Smart Grid Status and Metrics Report defines and examines 21 metrics that collectively provide insight into the grid’s capacity to embody these characteristics. This appendix presents papersmore » covering each of the 21 metrics identified in Section 2.1 of the Smart Grid Status and Metrics Report. These metric papers were prepared in advance of the main body of the report and collectively form its informational backbone.« less

Micro-Grids for Colonias (TX)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dean Schneider; Michael Martin; Renee Berry

2012-07-31

This report describes the results of the final implementation and testing of a hybrid micro-grid system designed for off-grid applications in underserved Colonias along the Texas/Mexico border. The project is a federally funded follow-on to a project funded by the Texas State Energy Conservation Office in 2007 that developed and demonstrated initial prototype hybrid generation systems consisting of a proprietary energy storage technology, high efficiency charging and inverting systems, photovoltaic cells, a wind turbine, and bio-diesel generators. This combination of technologies provided continuous power to dwellings that are not grid connected, with a significant savings in fuel by allowing powermore » generation at highly efficient operating conditions. The objective of this project was to complete development of the prototype systems and to finalize and engineering design; to install and operate the systems in the intended environment, and to evaluate the technical and economic effectiveness of the systems. The objectives of this project were met. This report documents the final design that was achieved and includes the engineering design documents for the system. The system operated as designed, with the system availability limited by maintenance requirements of the diesel gensets. Overall, the system achieved a 96% availability over the operation of the three deployed systems. Capital costs of the systems were dependent upon both the size of the generation system and the scope of the distribution grid, but, in this instance, the systems averaged $0.72/kWh delivered. This cost would decrease significantly as utilization of the system increased. The system with the highest utilization achieved a capitol cost amortized value of $0.34/kWh produced. The average amortized fuel and maintenance cost was $0.48/kWh which was dependent upon the amount of maintenance required by the diesel generator. Economically, the system is difficult to justify as an alternative to grid power. However, the operational costs are reasonable if grid power is unavailable, e.g. in a remote area or in a disaster recovery situation. In fact, avoided fuel costs for the smaller of the systems in use during this project would have a payback of the capital costs of that system in 2.3 years, far short of the effective system life.« less

Cloud computing for energy management in smart grid - an application survey

NASA Astrophysics Data System (ADS)

Naveen, P.; Kiing Ing, Wong; Kobina Danquah, Michael; Sidhu, Amandeep S.; Abu-Siada, Ahmed

2016-03-01

The smart grid is the emerging energy system wherein the application of information technology, tools and techniques that make the grid run more efficiently. It possesses demand response capacity to help balance electrical consumption with supply. The challenges and opportunities of emerging and future smart grids can be addressed by cloud computing. To focus on these requirements, we provide an in-depth survey on different cloud computing applications for energy management in the smart grid architecture. In this survey, we present an outline of the current state of research on smart grid development. We also propose a model of cloud based economic power dispatch for smart grid.

Recording wildlife locations with the Universal Transverse Mercator (UTM) grid system

Treesearch

T. G. Grubb; W. L. Eakle

1988-01-01

The Universal Transverse Mercator (UTM) international, planar, grid system is described and shown to offer greater simplicity, efficiency and accuracy for plotting wildlife locations than the more familiar Latitude-Longitude (Latilong) and Section-Township-Range (Cadastral) systems, and the State planar system. Use of the UTM system is explained with examples.

Ion beam accelerator system

NASA Technical Reports Server (NTRS)

Aston, Graeme (Inventor)

1984-01-01

A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

Automated food microbiology: potential for the hydrophobic grid-membrane filter.

PubMed Central

Sharpe, A N; Diotte, M P; Dudas, I; Michaud, G L

1978-01-01

Bacterial counts obtained on hydrophobic grid-membrane filters were comparable to conventional plate counts for Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus in homogenates from a range of foods. The wide numerical operating range of the hydrophobic grid-membrane filters allowed sequential diluting to be reduced or even eliminated, making them attractive as components in automated systems of analysis. Food debris could be rinsed completely from the unincubated hydrophobic grid-membrane filter surface without affecting the subsequent count, thus eliminating the possibility of counting food particles, a common source of error in electronic counting systems. PMID:100054

Energy, variability and weather finance engineering

NASA Astrophysics Data System (ADS)

Roussis, Dimitrios; Parara, Iliana; Gournari, Panagiota; Moustakis, Yiannis; Dimitriadis, Panayiotis; Iliopoulou, Theano; Koutsoyiannis, Demetris; Karakatsanis, Georgios

2017-04-01

Most types of renewable energies are characterized by intense intermittency, causing significant instabilities to the grid; further requiring additional infrastructure (e.g. pumped-storage) for buffering hydrometeorological uncertainties, as well as complex operational rules for load balancing. In addition, most intermittent renewable units are subsidized, creating significant market inefficiencies. Weather derivatives comprise mature financial tools for integrating successfully the intermittent-load and base-load components into a unified hybrid energy system and establish their operation within a generalized uncertainty management market. With a growing global market share and 46% utilization of this financial tool by the energy industry and 12% by agriculture (that partially concerns biofuel resources), weather derivatives are projected to constitute a critical subsystem of many grids for buffering frequent hydrometeorological risks of low and medium impacts -which are not covered by standard insurance contracts that aim exclusively at extreme events and high financial damages. In this context, we study the attributes of hydrometeorological time series in a remote and small island in Greece, powered by an autonomous hybrid energy system. Upon the results we choose the optimal underlying index and we further compose and engineer a weather derivative with features of a typical option contract -which we consider most flexible and appropriate for the case- to test our assumptions on its beneficiary effects for both the budget of private energy producers and the island's public administration. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

DISTRIBUTED GRID-CONNECTED PHOTOVOLTAIC POWER SYSTEM EMISSION OFFSET ASSESSMENT: STATISTICAL TEST OF SIMULATED- AND MEASURED-BASED DATA

EPA Science Inventory

This study assessed the pollutant emission offset potential of distributed grid-connected photovoltaic (PV) power systems. Computer-simulated performance results were utilized for 211 PV systems located across the U.S. The PV systems' monthly electrical energy outputs were based ...

Synchrotron Imaging Computations on the Grid without the Computing Element

NASA Astrophysics Data System (ADS)

Curri, A.; Pugliese, R.; Borghes, R.; Kourousias, G.

2011-12-01

Besides the heavy use of the Grid in the Synchrotron Radiation Facility (SRF) Elettra, additional special requirements from the beamlines had to be satisfied through a novel solution that we present in this work. In the traditional Grid Computing paradigm the computations are performed on the Worker Nodes of the grid element known as the Computing Element. A Grid middleware extension that our team has been working on, is that of the Instrument Element. In general it is used to Grid-enable instrumentation; and it can be seen as a neighbouring concept to that of the traditional Control Systems. As a further extension we demonstrate the Instrument Element as the steering mechanism for a series of computations. In our deployment it interfaces a Control System that manages a series of computational demanding Scientific Imaging tasks in an online manner. The instrument control in Elettra is done through a suitable Distributed Control System, a common approach in the SRF community. The applications that we present are for a beamline working in medical imaging. The solution resulted to a substantial improvement of a Computed Tomography workflow. The near-real-time requirements could not have been easily satisfied from our Grid's middleware (gLite) due to the various latencies often occurred during the job submission and queuing phases. Moreover the required deployment of a set of TANGO devices could not have been done in a standard gLite WN. Besides the avoidance of certain core Grid components, the Grid Security infrastructure has been utilised in the final solution.

How to deal with petabytes of data: the LHC Grid project

NASA Astrophysics Data System (ADS)

Britton, D.; Lloyd, S. L.

2014-06-01

We review the Grid computing system developed by the international community to deal with the petabytes of data coming from the Large Hadron Collider at CERN in Geneva with particular emphasis on the ATLAS experiment and the UK Grid project, GridPP. Although these developments were started over a decade ago, this article explains their continued relevance as part of the ‘Big Data’ problem and how the Grid has been forerunner of today's cloud computing.

ION ACCELERATION SYSTEM

DOEpatents

Luce, J.S.; Martin, J.A.

1960-02-23

Well focused, intense ion beams are obtained by providing a multi- apertured source grid in front of an ion source chamber and an accelerating multi- apertured grid closely spaced from and in alignment with the source grid. The longest dimensions of the elongated apertures in the grids are normal to the direction of the magnetic field used with the device. Large ion currents may be withdrawn from the source, since they do not pass through any small focal region between the grids.

A Framework for Testing Automated Detection, Diagnosis, and Remediation Systems on the Smart Grid

NASA Technical Reports Server (NTRS)

Lau, Shing-hon

2011-01-01

America's electrical grid is currently undergoing a multi-billion dollar modernization effort aimed at producing a highly reliable critical national infrastructure for power - a Smart Grid. While the goals for the Smart Grid include upgrades to accommodate large quantities of clean, but transient, renewable energy and upgrades to provide customers with real-time pricing information, perhaps the most important objective is to create an electrical grid with a greatly increased robustness.

Dc microgrid stabilization through fuzzy control of interleaved, heterogeneous storage elements

NASA Astrophysics Data System (ADS)

Smith, Robert David

As microgrid power systems gain prevalence and renewable energy comprises greater and greater portions of distributed generation, energy storage becomes important to offset the higher variance of renewable energy sources and maximize their usefulness. One of the emerging techniques is to utilize a combination of lead-acid batteries and ultracapacitors to provide both short and long-term stabilization to microgrid systems. The different energy and power characteristics of batteries and ultracapacitors imply that they ought to be utilized in different ways. Traditional linear controls can use these energy storage systems to stabilize a power grid, but cannot effect more complex interactions. This research explores a fuzzy logic approach to microgrid stabilization. The ability of a fuzzy logic controller to regulate a dc bus in the presence of source and load fluctuations, in a manner comparable to traditional linear control systems, is explored and demonstrated. Furthermore, the expanded capabilities (such as storage balancing, self-protection, and battery optimization) of a fuzzy logic system over a traditional linear control system are shown. System simulation results are presented and validated through hardware-based experiments. These experiments confirm the capabilities of the fuzzy logic control system to regulate bus voltage, balance storage elements, optimize battery usage, and effect self-protection.

A System for Monitoring and Management of Computational Grids

NASA Technical Reports Server (NTRS)

Smith, Warren; Biegel, Bryan (Technical Monitor)

2002-01-01

As organizations begin to deploy large computational grids, it has become apparent that systems for observation and control of the resources, services, and applications that make up such grids are needed. Administrators must observe the operation of resources and services to ensure that they are operating correctly and they must control the resources and services to ensure that their operation meets the needs of users. Users are also interested in the operation of resources and services so that they can choose the most appropriate ones to use. In this paper we describe a prototype system to monitor and manage computational grids and describe the general software framework for control and observation in distributed environments that it is based on.

A Petri Net model for distributed energy system

NASA Astrophysics Data System (ADS)

Konopko, Joanna

2015-12-01

Electrical networks need to evolve to become more intelligent, more flexible and less costly. The smart grid is the next generation power energy, uses two-way flows of electricity and information to create a distributed automated energy delivery network. Building a comprehensive smart grid is a challenge for system protection, optimization and energy efficient. Proper modeling and analysis is needed to build an extensive distributed energy system and intelligent electricity infrastructure. In this paper, the whole model of smart grid have been proposed using Generalized Stochastic Petri Nets (GSPN). The simulation of created model is also explored. The simulation of the model has allowed the analysis of how close the behavior of the model is to the usage of the real smart grid.

A high throughput geocomputing system for remote sensing quantitative retrieval and a case study

NASA Astrophysics Data System (ADS)

Xue, Yong; Chen, Ziqiang; Xu, Hui; Ai, Jianwen; Jiang, Shuzheng; Li, Yingjie; Wang, Ying; Guang, Jie; Mei, Linlu; Jiao, Xijuan; He, Xingwei; Hou, Tingting

2011-12-01

The quality and accuracy of remote sensing instruments have been improved significantly, however, rapid processing of large-scale remote sensing data becomes the bottleneck for remote sensing quantitative retrieval applications. The remote sensing quantitative retrieval is a data-intensive computation application, which is one of the research issues of high throughput computation. The remote sensing quantitative retrieval Grid workflow is a high-level core component of remote sensing Grid, which is used to support the modeling, reconstruction and implementation of large-scale complex applications of remote sensing science. In this paper, we intend to study middleware components of the remote sensing Grid - the dynamic Grid workflow based on the remote sensing quantitative retrieval application on Grid platform. We designed a novel architecture for the remote sensing Grid workflow. According to this architecture, we constructed the Remote Sensing Information Service Grid Node (RSSN) with Condor. We developed a graphic user interface (GUI) tools to compose remote sensing processing Grid workflows, and took the aerosol optical depth (AOD) retrieval as an example. The case study showed that significant improvement in the system performance could be achieved with this implementation. The results also give a perspective on the potential of applying Grid workflow practices to remote sensing quantitative retrieval problems using commodity class PCs.

Design and Implementation of Real-Time Off-Grid Detection Tool Based on FNET/GridEye

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Jiahui; Zhang, Ye; Liu, Yilu

2014-01-01

Real-time situational awareness tools are of critical importance to power system operators, especially during emergencies. The availability of electric power has become a linchpin of most post disaster response efforts as it is the primary dependency for public and private sector services, as well as individuals. Knowledge of the scope and extent of facilities impacted, as well as the duration of their dependence on backup power, enables emergency response officials to plan for contingencies and provide better overall response. Based on real-time data acquired by Frequency Disturbance Recorders (FDRs) deployed in the North American power grid, a real-time detection methodmore » is proposed. This method monitors critical electrical loads and detects the transition of these loads from an on-grid state, where the loads are fed by the power grid to an off-grid state, where the loads are fed by an Uninterrupted Power Supply (UPS) or a backup generation system. The details of the proposed detection algorithm are presented, and some case studies and off-grid detection scenarios are also provided to verify the effectiveness and robustness. Meanwhile, the algorithm has already been implemented based on the Grid Solutions Framework (GSF) and has effectively detected several off-grid situations.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, Thomas M.; Boudreau, Marie-Claude; Helsen, Lieve

Recent advances in information and communications technology (ICT) have initiated development of a smart electrical grid and smart buildings. Buildings consume a large portion of the total electricity production worldwide, and to fully develop a smart grid they must be integrated with that grid. Buildings can now be 'prosumers' on the grid (both producers and consumers), and the continued growth of distributed renewable energy generation is raising new challenges in terms of grid stability over various time scales. Buildings can contribute to grid stability by managing their overall electrical demand in response to current conditions. Facility managers must balance demandmore » response requests by grid operators with energy needed to maintain smooth building operations. For example, maintaining thermal comfort within an occupied building requires energy and, thus an optimized solution balancing energy use with indoor environmental quality (adequate thermal comfort, lighting, etc.) is needed. Successful integration of buildings and their systems with the grid also requires interoperable data exchange. However, the adoption and integration of newer control and communication technologies into buildings can be problematic with older legacy HVAC and building control systems. Public policy and economic structures have not kept up with the technical developments that have given rise to the budding smart grid, and further developments are needed in both technical and non-technical areas.« less

Cybersecurity for a Modern Grid - Video Text Version | Energy Systems

Science.gov Websites

got the facilities and the capability, and the people that really understand where the grid is evolving. I think many people are focused on securing today's grid...we're gonna be focused on