Science.gov

Sample records for ac power grid

  1. Utility-Scale Power Router: Dynamic Control of Grid Assets Using Direct AC Converter Cells

    SciTech Connect

    2010-09-01

    ADEPT Project: Georgia Tech is developing a cost-effective, utility-scale power router that uses an enhanced transformer to more efficiently direct power on the grid. Existing power routing technologies are too expensive for widespread use, but the ability to route grid power to match real-time demand and power outages would significantly reduce energy costs for utilities, municipalities, and consumers. Georgia Tech is adding a power converter to an existing grid transformer to better control power flows at about 1/10th the cost of existing power routing solutions. Transformers convert the high-voltage electricity that is transmitted through the grid into the low-voltage electricity that is used by homes and businesses. The added converter uses fewer steps to convert some types of power and eliminates unnecessary power storage, among other improvements. The enhanced transformer is more efficient, and it would still work even if the converter fails, ensuring grid reliability.

  2. Thermionic triode generates ac power

    NASA Technical Reports Server (NTRS)

    Kniazzeh, A. G. F.; Scharz, F. C.

    1970-01-01

    Electrostatic grid controls conduction cycle of thermionic diode to convert low dc output voltages to high ac power without undesirable power loss. An ac voltage applied to the grid of this new thermionic triode enables it to convert heat directly into high voltage electrical power.

  3. Dynamic Power Grid Simulation

    2015-09-14

    GridDyn is a part of power grid simulation toolkit. The code is designed using modern object oriented C++ methods utilizing C++11 and recent Boost libraries to ensure compatibility with multiple operating systems and environments.

  4. AC power systems handbook

    SciTech Connect

    Whitaker, J.

    1991-01-01

    Transient disturbances are what headaches are made of. Whatever you call them-spikes, surges, are power bumps-they can take your equipment down and leave you with a complicated and expensive repair job. Protection against transient disturbances is a science that demands attention to detail. This book explains how the power distribution system works, what can go wrong with it, and how to protect a facility against abnormalities. system grounding and shielding are covered in detail. Each major method of transient protection is analyzed and its relative merits discussed. The book provides a complete look at the critical elements of the ac power system. Provides a complete look at the ac power system from generation to consumption. Discusses the mechanisms that produce transient disturbances and how to protect against them. Presents diagrams to facilitate system design. Covers new areas, such as the extent of the transient disturbance problem, transient protection options, and stand-by power systems.

  5. Long-range response in ac electricity grids.

    PubMed

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013)EPJBFY1434-602810.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology-for example, caused by power outages or grid extensions-a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014)1951-635510.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found. PMID:27575148

  6. Long-range response in ac electricity grids

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  7. Information Power Grid Posters

    NASA Technical Reports Server (NTRS)

    Vaziri, Arsi

    2003-01-01

    This document is a summary of the accomplishments of the Information Power Grid (IPG). Grids are an emerging technology that provide seamless and uniform access to the geographically dispersed, computational, data storage, networking, instruments, and software resources needed for solving large-scale scientific and engineering problems. The goal of the NASA IPG is to use NASA's remotely located computing and data system resources to build distributed systems that can address problems that are too large or complex for a single site. The accomplishments outlined in this poster presentation are: access to distributed data, IPG heterogeneous computing, integration of large-scale computing node into distributed environment, remote access to high data rate instruments,and exploratory grid environment.

  8. IPG Power Grid Overview

    NASA Technical Reports Server (NTRS)

    Hinke, Thomas

    2003-01-01

    This presentation will describe what is meant by grids and then cover the current state of the IPG. This will include an overview of the middleware that is key to the operation of the grid. The presentation will then describe some of the future directions that are planned for the IPG. Finally the presentation will conclude with a brief overview of the Global Grid Forum, which is a key activity that will contribute to the successful availability of grid components.

  9. AC power system breadboard

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.; Sundberg, R.; Mildice, J.; Peterson, D.; Hushing, S.

    1987-01-01

    The object of this program was to design, build, test, and deliver a high-frequency (20-kHz) Power System Breadboard which would electrically approximate a pair of dual redundant power channels of an IOC Space Station. This report describes that program, including the technical background, and discusses the results, showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment has been completed and delivered to LeRC, where it is operating as a part of the Space Station Power System Test Facility.

  10. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  11. Semiconductor ac static power switch

    NASA Technical Reports Server (NTRS)

    Vrancik, J.

    1968-01-01

    Semiconductor ac static power switch has long life and high reliability, contains no moving parts, and operates satisfactorily in severe environments, including high vibration and shock conditions. Due to their resistance to shock and vibration, static switches are used where accidental switching caused by mechanical vibration or shock cannot be tolerated.

  12. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  13. POWER GRID RELIABILITY AND SECURITY

    SciTech Connect

    Bose, Anjan; Venkatasubramanian, Vaithianathan; Hauser, Carl; Bakken, David; Anderson, David; Zhao, Chuanlin; Liu, Dong; Yang, Tao; Meng, Ming; Zhang, Lin; Ning, Jiawei; Tashman, Zaid

    2014-09-30

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

  14. Parallel Power Grid Simulation Toolkit

    SciTech Connect

    Smith, Steve; Kelley, Brian; Banks, Lawrence; Top, Philip; Woodward, Carol

    2015-09-14

    ParGrid is a 'wrapper' that integrates a coupled Power Grid Simulation toolkit consisting of a library to manage the synchronization and communication of independent simulations. The included library code in ParGid, named FSKIT, is intended to support the coupling multiple continuous and discrete even parallel simulations. The code is designed using modern object oriented C++ methods utilizing C++11 and current Boost libraries to ensure compatibility with multiple operating systems and environments.

  15. Solar Power Grid Unfurled

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Shown here is one of the first images taken by NASA's Phoenix Mars Lander of one of the octagonal solar panels, which opened like two handheld, collapsible fans on either side of the spacecraft. Beyond this view is a small slice of the north polar terrain of Mars.

    The successfully deployed solar panels are critical to the success of the 90-day mission, as they are the spacecraft's only means of replenishing its power. Even before these images reached Earth, power readings from the spacecraft indicated to engineers that the solar panels were already at work recharging the spacecraft's batteries.

    Before deploying the Surface Stereo Imager to take these images, the lander waited about 15 minutes for the dust to settle.

    This image was taken by the spacecraft's Surface Stereo Imager on Sol, or Martian day, 0 (May 25, 2008).

    This image has been geometrically corrected.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. Solar Power Grid

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Shown here is one of the first images taken by NASA's Phoenix Mars Lander of one of the octagonal solar panels, which opened like two handheld, collapsible fans on either side of the spacecraft. Beyond this view is a small slice of the north polar terrain of Mars.

    The successfully deployed solar panels are critical to the success of the 90-day mission, as they are the spacecraft's only means of replenishing its power. Even before these images reached Earth, power readings from the spacecraft indicated to engineers that the solar panels were already at work recharging the spacecraft's batteries.

    Before deploying the Surface Stereo Imager to take these images, the lander waited about 15 minutes for the dust to settle.

    This image was taken by the spacecraft's Surface Stereo Imager on Sol, or Martian day, 0 (May 25, 2008).

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  17. Development of a low-cost integrated 20-kW ac solar tracking sub- array for grid-connected PV power system applications. Phase 1, Annual technical report, 11 July 1995--31 July 1996

    SciTech Connect

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

    1997-06-01

    The overall goal of this effort is to reduce the installed cost of utility scale grid connected photovoltaic power systems. The focus of the effort is on ``BOS`` (Balance-Of-System) component manufacturing technology, which essentially involves all PV power system engineering, manufacturing, assembly and construction tasks from the receipt of a PV module to the deliver of grid connected electricity.

  18. Visual analytics for power grid contingency analysis.

    PubMed

    Pak Chung Wong; Zhenyu Huang; Yousu Chen; Mackey, Patrick; Shuangshuang Jin

    2014-01-01

    Contingency analysis employs different measures to model scenarios, analyze them, and then derive the best response to any threats. A proposed visual-analytics pipeline for power grid management can transform approximately 100 million contingency scenarios to a manageable size and form. Grid operators can examine individual scenarios and devise preventive or mitigation strategies in a timely manner. Power grid engineers have applied the pipeline to a Western Electricity Coordinating Council power grid model. PMID:24808167

  19. Evaluating the Information Power Grid using the NAS Grid Benchmarks

    NASA Technical Reports Server (NTRS)

    VanderWijngaartm Rob F.; Frumkin, Michael A.

    2004-01-01

    The NAS Grid Benchmarks (NGB) are a collection of synthetic distributed applications designed to rate the performance and functionality of computational grids. We compare several implementations of the NGB to determine programmability and efficiency of NASA's Information Power Grid (IPG), whose services are mostly based on the Globus Toolkit. We report on the overheads involved in porting existing NGB reference implementations to the IPG. No changes were made to the component tasks of the NGB can still be improved.

  20. Operation Method for AC Motor Control during Power Interruption in Direct AC/AC Converter System

    NASA Astrophysics Data System (ADS)

    Shizu, Keiichiro; Azuma, Satoshi

    Direct AC/AC converters have been studied due to their potential use in power converters with no DC-link capacitor, which can contribute to the miniaturization of power converters. However, the absence of a DC-link capacitor makes it difficult to control the AC motor during power interruption. First, this paper proposes a system that realizes AC motor control during power interruption by utilizing a clamp capacitor. In general, direct AC/AC converters have a clamp circuit consisting of a rectifier diode(s) and a clamp capacitor in order to avoid over-voltages. In the proposed system, there is an additional semiconductor switch reverse-parallel to the rectifier diode(s), and the clamp capacitor voltage can be utilized for AC motor control by turning on the additional switch. Second, this paper discusses an operation method for AC motor control and clamp capacitor voltage control during power interruption. In the proposed method “DC-link voltage control”, the kinetic energy in the AC motor is transformed into electrical energy and stored in the clamp capacitor; the clamp capacitor is therefore charged and the capacitor voltage is controlled to remain constant at an instruction value. Third, this paper discusses a switching operation during power interruption. A dead-time is introduced between the operation of turning off all switches on the rectifier side and the operation of turning on the additional switch, which prevents the occurrence of a short circuit between the interrupted power source and the clamp capacitor. Finally, experimental results are presented. During power interruptions, an output current was continuously obtained and the clamp capacitor voltage was maintained to be equal to the instruction value of the capacitor voltage. These results indicate that both AC motor control and capacitor voltage control were successfully achieved by using the proposed system.

  1. Application Note: Power Grid Modeling With Xyce.

    SciTech Connect

    Sholander, Peter E.

    2015-06-01

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

  2. 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.

  3. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  4. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  5. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  6. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  7. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  8. 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

  9. The ac power system testbed

    NASA Technical Reports Server (NTRS)

    Mildice, J.; Sundberg, R.

    1987-01-01

    The object of this program was to design, build, test, and deliver a high frequency (20 kHz) Power System Testbed which would electrically approximate a single, separable power channel of an IOC Space Station. That program is described, including the technical background, and the results are discussed showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment was completed and delivered and is being operated as part of the Space Station Power System Test Facility.

  10. Voltage collapse in complex power grids

    PubMed Central

    Simpson-Porco, John W.; Dörfler, Florian; Bullo, Francesco

    2016-01-01

    A large-scale power grid's ability to transfer energy from producers to consumers is constrained by both the network structure and the nonlinear physics of power flow. Violations of these constraints have been observed to result in voltage collapse blackouts, where nodal voltages slowly decline before precipitously falling. However, methods to test for voltage collapse are dominantly simulation-based, offering little theoretical insight into how grid structure influences stability margins. For a simplified power flow model, here we derive a closed-form condition under which a power network is safe from voltage collapse. The condition combines the complex structure of the network with the reactive power demands of loads to produce a node-by-node measure of grid stress, a prediction of the largest nodal voltage deviation, and an estimate of the distance to collapse. We extensively test our predictions on large-scale systems, highlighting how our condition can be leveraged to increase grid stability margins. PMID:26887284

  11. Spontaneous synchrony in power-grid networks

    NASA Astrophysics Data System (ADS)

    Motter, Adilson E.; Myers, Seth A.; Anghel, Marian; Nishikawa, Takashi

    2013-03-01

    An imperative condition for the functioning of a power-grid network is that its power generators remain synchronized. Disturbances can prompt desynchronization, which is a process that has been involved in large power outages. Here we derive a condition under which the desired synchronous state of a power grid is stable, and use this condition to identify tunable parameters of the generators that are determinants of spontaneous synchronization. Our analysis gives rise to an approach to specify parameter assignments that can enhance synchronization of any given network, which we demonstrate for a selection of both test systems and real power grids. These findings may be used to optimize stability and help devise new control schemes, thus offering an additional layer of protection and contributing to the development of smart grids that can recover from failures in real time.

  12. 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.

  13. Power control for ac motor

    NASA Technical Reports Server (NTRS)

    Dabney, R. W. (Inventor)

    1984-01-01

    A motor controller employing a triac through which power is supplied to a motor is described. The open circuit voltage appearing across the triac controls the operation of a timing circuit. This timing circuit triggers on the triac at a time following turn off which varies inversely as a function of the amplitude of the open circuit voltage of the triac.

  14. Inverters for interfacing of solar cells with the power grid

    NASA Astrophysics Data System (ADS)

    Karamanzanis, G. N.; Jackson, R. D.

    In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and they provide a satisfactory output current waveform in phase to the a.c. line voltage. The problems of control are also studied using a suitable mathematical model.

  15. Power Electronic Transformer based Three-Phase PWM AC Drives

    NASA Astrophysics Data System (ADS)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  16. Reliability of emergency ac power systems at nuclear power plants

    SciTech Connect

    Battle, R E; Campbell, D J

    1983-07-01

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.

  17. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered photostimulator. 886.1630 Section 886.1630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus...

  18. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered photostimulator. 886.1630 Section 886.1630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus...

  19. Visual Analytics for Power Grid Contingency Analysis

    SciTech Connect

    Wong, Pak C.; Huang, Zhenyu; Chen, Yousu; Mackey, Patrick S.; Jin, Shuangshuang

    2014-01-20

    Contingency analysis is the process of employing different measures to model scenarios, analyze them, and then derive the best response to remove the threats. This application paper focuses on a class of contingency analysis problems found in the power grid management system. A power grid is a geographically distributed interconnected transmission network that transmits and delivers electricity from generators to end users. The power grid contingency analysis problem is increasingly important because of both the growing size of the underlying raw data that need to be analyzed and the urgency to deliver working solutions in an aggressive timeframe. Failure to do so may bring significant financial, economic, and security impacts to all parties involved and the society at large. The paper presents a scalable visual analytics pipeline that transforms about 100 million contingency scenarios to a manageable size and form for grid operators to examine different scenarios and come up with preventive or mitigation strategies to address the problems in a predictive and timely manner. Great attention is given to the computational scalability, information scalability, visual scalability, and display scalability issues surrounding the data analytics pipeline. Most of the large-scale computation requirements of our work are conducted on a Cray XMT multi-threaded parallel computer. The paper demonstrates a number of examples using western North American power grid models and data.

  20. Energy Storage for the Power Grid

    SciTech Connect

    Imhoff, Carl; Vaishnav, Dave

    2014-07-01

    The iron vanadium redox flow battery was developed by researchers at Pacific Northwest National Laboratory as a solution to large-scale energy storage for the power grid. This technology provides the energy industry and the nation with a reliable, stable, safe, and low-cost storage alternative for a cleaner, efficient energy future.

  1. Abruptness of Cascade Failures in Power Grids

    NASA Astrophysics Data System (ADS)

    Pahwa, Sakshi; Scoglio, Caterina; Scala, Antonio

    2014-01-01

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

  2. Abruptness of cascade failures in power grids.

    PubMed

    Pahwa, Sakshi; Scoglio, Caterina; Scala, Antonio

    2014-01-01

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

  3. Real Time Simulation of Power Grid Disruptions

    SciTech Connect

    Chinthavali, Supriya; Dimitrovski, Aleksandar D; Fernandez, Steven J; Groer, Christopher S; Nutaro, James J; Olama, Mohammed M; Omitaomu, Olufemi A; Shankar, Mallikarjun; Spafford, Kyle L; Vacaliuc, Bogdan

    2012-11-01

    DOE-OE and DOE-SC workshops (Reference 1-3) identified the key power grid problem that requires insight addressable by the next generation of exascale computing is coupling of real-time data streams (1-2 TB per hour) as the streams are ingested to dynamic models. These models would then identify predicted disruptions in time (2-4 seconds) to trigger the smart grid s self healing functions. This project attempted to establish the feasibility of this approach and defined the scientific issues, and demonstrated example solutions to important smart grid simulation problems. These objectives were accomplished by 1) using the existing frequency recorders on the national grid to establish a representative and scalable real-time data stream; 2) invoking ORNL signature identification algorithms; 3) modeling dynamically a representative region of the Eastern interconnect using an institutional cluster, measuring the scalability and computational benchmarks for a national capability; and 4) constructing a prototype simulation for the system s concept of smart grid deployment. The delivered ORNL enduring capability included: 1) data processing and simulation metrics to design a national capability justifying exascale applications; 2) Software and intellectual property built around the example solutions; 3) demonstrated dynamic models to design few second self-healing.

  4. Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

    NASA Technical Reports Server (NTRS)

    Reitan, D. K.

    1973-01-01

    Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

  5. High-Voltage, High-Power Gaseous Electronics Switch For Electric Grid Power Conversion

    NASA Astrophysics Data System (ADS)

    Sommerer, Timothy J.

    2014-05-01

    We are developing a high-voltage, high-power gas switch for use in low-cost power conversion terminals on the electric power grid. Direct-current (dc) power transmission has many advantages over alternating current (ac) transmission, but at present the high cost of ac-dc power interconversion limits the use of dc. The gas switch we are developing conducts current through a magnetized cold cathode plasma in hydrogen or helium to reach practical current densities > 1 A/cm2. Thermal and sputter damage of the cathode by the incident ion flux is a major technical risk, and is being addressed through use of a ``self-healing'' liquid metal cathode (eg, gallium). Plasma conditions and cathode sputtering loss are estimated by analyzing plasma spectral emission. A particle-in-cell plasma model is used to understand various aspects of switch operation, including the conduction phase (where plasma densities can exceed 1013 cm-3), the switch-open phase (where the high-voltage must be held against gas breakdown on the left side of Paschen's curve), and the switching transitions (especially the opening process, which is initiated by forming an ion-matrix sheath adjacent to a control grid). The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000298.

  6. Millimeterwave Space Power Grid architecture development 2012

    NASA Astrophysics Data System (ADS)

    Komerath, Narayanan; Dessanti, Brendan; Shah, Shaan

    This is an update of the Space Power Grid architecture for space-based solar power with an improved design of the collector/converter link, the primary heater and the radiator of the active thermal control system. The Space Power Grid offers an evolutionary approach towards TeraWatt-level Space-based solar power. The use of millimeter wave frequencies (around 220GHz) and Low-Mid Earth Orbits shrinks the size of the space and ground infrastructure to manageable levels. In prior work we showed that using Brayton cycle conversion of solar power allows large economies of scale compared to the linear mass-power relationship of photovoltaic conversion. With high-temperature materials permitting 3600 K temperature in the primary heater, over 80 percent cycle efficiency was shown with a closed helium cycle for the 1GW converter satellite which formed the core element of the architecture. Work done since the last IEEE conference has shown that the use of waveguides incorporated into lighter-than-air antenna platforms, can overcome the difficulties in transmitting millimeter wave power through the moist, dense lower atmosphere. A graphene-based radiator design conservatively meets the mass budget for the waste heat rejection system needed for the compressor inlet temperature. Placing the ultralight Mirasol collectors in lower orbits overcomes the solar beam spot size problem of high-orbit collection. The architecture begins by establishing a power exchange with terrestrial renewable energy plants, creating an early revenue generation approach with low investment. The approach allows for technology development and demonstration of high power millimeter wave technology. A multinational experiment using the International Space Station and another power exchange satellite is proposed to gather required data and experience, thus reducing the technical and policy risks. The full-scale architecture deploys pairs of Mirasol sunlight collectors and Girasol 1 GW converter satellites t

  7. Geographic Visualization of Power-Grid Dynamics

    2015-06-18

    The visualization enables the simulation analyst to see changes in the frequency through time and space. With this technology, the analyst has a bird's eye view of the frequency at loads and generators as the simulated power system responds to the loss of a generator, spikes in load, and other contingencies. The significance of a contingency to the operation of an electrical power system depends critically on how the resulting tansients evolve in time andmore » space. Consequently, these dynamic events can only be understood when seen in their proper geographic context. this understanding is indispensable to engineers working on the next generation of distributed sensing and control systems for the smart grid. By making possible a natural and intuitive presentation of dynamic behavior, our new visualization technology is a situational-awareness tool for power-system engineers.« less

  8. Geographic Visualization of Power-Grid Dynamics

    SciTech Connect

    Sukumar, Sreenivas R.

    2015-06-18

    The visualization enables the simulation analyst to see changes in the frequency through time and space. With this technology, the analyst has a bird's eye view of the frequency at loads and generators as the simulated power system responds to the loss of a generator, spikes in load, and other contingencies. The significance of a contingency to the operation of an electrical power system depends critically on how the resulting tansients evolve in time and space. Consequently, these dynamic events can only be understood when seen in their proper geographic context. this understanding is indispensable to engineers working on the next generation of distributed sensing and control systems for the smart grid. By making possible a natural and intuitive presentation of dynamic behavior, our new visualization technology is a situational-awareness tool for power-system engineers.

  9. High-frequency ac power distribution in Space Station

    NASA Technical Reports Server (NTRS)

    Tsai, Fu-Sheng; Lee, Fred C. Y.

    1990-01-01

    A utility-type 20-kHz ac power distribution system for the Space Station, employing resonant power-conversion techniques, is presented. The system converts raw dc voltage from photovoltaic cells or three-phase LF ac voltage from a solar dynamic generator into a regulated 20-kHz ac voltage for distribution among various loads. The results of EASY5 computer simulations of the local and global performance show that the system has fast response and good transient behavior. The ac bus voltage is effectively regulated using the phase-control scheme, which is demonstrated with both line and load variations. The feasibility of paralleling the driver-module outputs is illustrated with the driver modules synchronized and sharing a common feedback loop. An HF sinusoidal ac voltage is generated in the three-phase ac input case, when the driver modules are phased 120 deg away from one another and their outputs are connected in series.

  10. Self-Organized Synchronization in Decentralized Power Grids

    NASA Astrophysics Data System (ADS)

    Rohden, Martin; Sorge, Andreas; Timme, Marc; Witthaut, Dirk

    2012-08-01

    Robust synchronization (phase locking) of power plants and consumers centrally underlies the stable operation of electric power grids. Despite current attempts to control large-scale networks, even their uncontrolled collective dynamics is not fully understood. Here we analyze conditions enabling self-organized synchronization in oscillator networks that serve as coarse-scale models for power grids, focusing on decentralizing power sources. Intriguingly, we find that whereas more decentralized grids become more sensitive to dynamical perturbations, they simultaneously become more robust to topological failures. Decentralizing power sources may thus facilitate the onset of synchronization in modern power grids.

  11. Programmable AC power supply for simulating power transient expected in fusion reactor

    SciTech Connect

    Halimi, B.; Suh, K. Y.

    2012-07-01

    This paper focus on control engineering of the programmable AC power source which has capability to simulate power transient expected in fusion reactor. To generate the programmable power source, AC-AC power electronics converter is adopted to control the power of a set of heaters to represent the transient phenomena of heat exchangers or heat sources of a fusion reactor. The International Thermonuclear Experimental Reactor (ITER) plasma operation scenario is used as the basic reference for producing this transient power source. (authors)

  12. How to Integrate Variable Power Source into a Power Grid

    NASA Astrophysics Data System (ADS)

    Asano, Hiroshi

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

  13. High-Frequency ac Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Mildice, James

    1987-01-01

    Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

  14. European Transmission Interconnection; Eurasian power grid

    SciTech Connect

    Posch, J. )

    1991-09-01

    Systems and philosophies perceived on a grand scale, encompassing new ideas, are often characterized as a dream. But in fact, such dreams often lead to the first step to fruitful development. This article is based on a preliminary study of the existing electrical high-tension networks of Western Europe, Eastern Europe and the Soviet Union - which, as explained herein, may be merged into a multinational energy supply system. Such a system would constitute a completely interconnected Eurasian Power Grid. The idea of a Eurasian super grid, spanning from the Atlantic to the Ural and Siberia, is not new. Various studies have been conducted by both western Europe and the Soviet Union on this topic. Our world is currently in an era of extra high voltage (EHV) and ultra high voltage (UHV) electrical systems. This translates into existing UHV lines of 1150 kV which have already been proven in successful operation. Such UHV systems are capable of transmitting thousands of megawatts over a distance of a 1000 miles. Furthermore, national boundaries are not more a hindrance than the challenge of interconnecting complete networks into an overall synchronized working system with load exchange capabilities in all directions.

  15. Power factor control system for AC induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1977-01-01

    A power factor control system for use with ac induction motors was designed which samples lines voltage and current through the motor and decreases power input to the motor proportional to the detected phase displacement between current and voltage. This system provides, less power to the motor, as it is less loaded.

  16. Power grid complex network evolutions for the smart grid

    NASA Astrophysics Data System (ADS)

    Pagani, Giuliano Andrea; Aiello, Marco

    2014-02-01

    The shift towards an energy grid dominated by prosumers (consumers and producers of energy) will inevitably have repercussions on the electricity distribution infrastructure. Today the grid is a hierarchical one delivering energy from large scale facilities to end-users. Tomorrow it will be a capillary infrastructure at the medium and low voltage levels that will support local energy trading among prosumers. We investigate how different network topologies and growth models facilitate a more efficient and reliable network, and how they can facilitate the emergence of a decentralized electricity market. We show how connectivity plays an important role in improving the properties of reliability and path-cost reduction. Our results indicate that a specific type of evolution balances best the ratio between increased connectivity and costs to achieve the network growth.

  17. Impact of network topology on synchrony of oscillatory power grids

    NASA Astrophysics Data System (ADS)

    Rohden, Martin; Sorge, Andreas; Witthaut, Dirk; Timme, Marc

    2014-03-01

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

  18. Impact of network topology on synchrony of oscillatory power grids

    SciTech Connect

    Rohden, Martin; Sorge, Andreas; Witthaut, Dirk; Timme, Marc

    2014-03-15

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

  19. Fabrication of a flexible Ag-grid transparent electrode using ac based electrohydrodynamic Jet printing

    NASA Astrophysics Data System (ADS)

    Park, Jaehong; Hwang, Jungho

    2014-10-01

    In the dc voltage-applied electrohydrodynamic (EHD) jet printing of metal nanoparticles, the residual charge of droplets deposited on a substrate changes the electrostatic field distribution and interrupts the subsequent printing behaviour, especially for insulating substrates that have slow charge decay rates. In this paper, a sinusoidal ac voltage was used in the EHD jet printing process to switch the charge polarity of droplets containing Ag nanoparticles, thereby neutralizing the charge on a polyethylene terephthalate (PET) substrate. Printed Ag lines with a width of 10 µm were invisible to the naked eye. After sintering lines with 500 µm of line pitch at 180 °C, a grid-type transparent electrode (TE) with a sheet resistance of ˜7 Ω sq-1 and a dc to optical conductivity ratio of ˜300 at ˜84.2% optical transmittance was obtained, values that were superior to previously reported results. In order to evaluate the durability of the TE under bending stresses, the sheet resistance was measured as the number of bending cycles was increased. The sheet resistance of the Ag grid electrode increased only slightly, by less than 20% from its original value, even after 500 cycles. To the best of our knowledge, this is the first time that Ag (invisible) grid TEs have been fabricated on PET substrates by ac voltage applied EHD jet printing.

  20. Systems Engineering Building Advances Power Grid Research

    SciTech Connect

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

    2015-08-19

    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.

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

    SciTech Connect

    2014-11-03

    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.

  2. High-power ac/dc variable load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.; Birnbach, S.; Bruce, L. D.; Smith, L.

    1975-01-01

    Design of medium-power dynamic electrical load simulator has been extended to permit simulation of ac as well as dc loads and to provide for operation at higher power levels. Simulator is internally protected against reverse voltage, overvoltage, overcurrent, and overload conditions.

  3. Save power in AC induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1977-01-01

    Relatively simple and inexpensive circuitry improves power factor and reduces power dissipation in induction motors operating below full load. Electronic control loop conserves energy by reducing voltage applied to lightly loaded motor. Circuit forces motor to run at constant predetermined optimum power factor, regardless of load or line voltage variations. Solid-state switch varies voltage.

  4. Information Power Grid (IPG) Tutorial 2003

    NASA Technical Reports Server (NTRS)

    Meyers, George

    2003-01-01

    For NASA and the general community today Grid middleware: a) provides tools to access/use data sources (databases, instruments, ...); b) provides tools to access computing (unique and generic); c) Is an enabler of large scale collaboration. Dynamically responding to needs is a key selling point of a grid. Independent resources can be joined as appropriate to solve a problem. Provide tools to enable the building of a frameworks for application. Provide value added service to the NASA user base for utilizing resources on the grid in new and more efficient ways. Provides tools for development of Frameworks.

  5. Introducing AC inductive reactance with a power tool

    NASA Astrophysics Data System (ADS)

    Bryant, Wesley; Baker, Blane

    2016-09-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance is smaller than expected, they are asked to explain these observations using previously studied principles of magnetic induction. Exercises also introduce the notion of inductive reactance and impedance in AC circuits and, ultimately, determine self-inductance of the motor windings within the power tool.

  6. A Data Miner for the Information Power Grid

    NASA Technical Reports Server (NTRS)

    Hinke, Thomas H.; Parks, John W. (Technical Monitor)

    2002-01-01

    Grid Miner (GM) is one of the early data mining applications developed by NASA to help users obtain information from the Information Power Grid (IPG). Topics cover include: benefits of data mining, potential use of grids in data mining activities, an overview of the GM application, and a brief review of GM architecture and implementation issues. The current status of the GM system is also discussed.

  7. Topology and vulnerability of the Iranian power grid

    NASA Astrophysics Data System (ADS)

    Saniee Monfared, Momhammad Ali; Jalili, Mahdi; Alipour, Zohreh

    2014-07-01

    In this paper we investigated the structural properties of the ultra high voltage power transmission network of Iran. We modeled the power grid as a network with 105 nodes and 142 connection links. We found that the Iranian power grid displays a relatively moderate clustering coefficient-much larger than that of corresponding random networks-and small characteristics path length comparable to that of corresponding random networks; i.e. the power grid is a small-world network with exponential degree distribution. Global efficiency was considered as an indicator of grid’s performance and the influence of random and intentional nodal failures on the efficiency was investigated. We also studied the influence of cascaded failures on the largest connected component of the network. The power grid was vulnerable against cascaded failures, which should be considered serious in redesigning the network topology.

  8. GridPACK Toolkit for Developing Power Grid Simulations on High Performance Computing Platforms

    SciTech Connect

    Palmer, Bruce J.; Perkins, William A.; Glass, Kevin A.; Chen, Yousu; Jin, Shuangshuang; Callahan, Charles D.

    2013-11-30

    This paper describes the GridPACK™ framework, which is designed to help power grid engineers develop modeling software capable of running on todays high performance computers. The framework contains modules for setting up distributed power grid networks, assigning buses and branches with arbitrary behaviors to the network, creating distributed matrices and vectors, using parallel linear and non-linear solvers to solve algebraic equations, and mapping functionality to create matrices and vectors based on properties of the network. In addition, the framework contains additional functionality to support IO and to manage errors.

  9. Resistojet control and power for high frequency ac buses

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P.

    1987-01-01

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.

  10. Resistojet control and power for high frequency ac buses

    NASA Astrophysics Data System (ADS)

    Gruber, Robert P.

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.

  11. Resistojet control and power for high frequency ac buses

    NASA Astrophysics Data System (ADS)

    Gruber, Robert P.

    1987-05-01

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.

  12. Operation of Power Grids with High Penetration of Wind Power

    NASA Astrophysics Data System (ADS)

    Al-Awami, Ali Taleb

    The integration of wind power into the power grid poses many challenges due to its highly uncertain nature. This dissertation involves two main components related to the operation of power grids with high penetration of wind energy: wind-thermal stochastic dispatch and wind-thermal coordinated bidding in short-term electricity markets. In the first part, a stochastic dispatch (SD) algorithm is proposed that takes into account the stochastic nature of the wind power output. The uncertainty associated with wind power output given the forecast is characterized using conditional probability density functions (CPDF). Several functions are examined to characterize wind uncertainty including Beta, Weibull, Extreme Value, Generalized Extreme Value, and Mixed Gaussian distributions. The unique characteristics of the Mixed Gaussian distribution are then utilized to facilitate the speed of convergence of the SD algorithm. A case study is carried out to evaluate the effectiveness of the proposed algorithm. Then, the SD algorithm is extended to simultaneously optimize the system operating costs and emissions. A modified multi-objective particle swarm optimization algorithm is suggested to identify the Pareto-optimal solutions defined by the two conflicting objectives. A sensitivity analysis is carried out to study the effect of changing load level and imbalance cost factors on the Pareto front. In the second part of this dissertation, coordinated trading of wind and thermal energy is proposed to mitigate risks due to those uncertainties. The problem of wind-thermal coordinated trading is formulated as a mixed-integer stochastic linear program. The objective is to obtain the optimal tradeoff bidding strategy that maximizes the total expected profits while controlling trading risks. For risk control, a weighted term of the conditional value at risk (CVaR) is included in the objective function. The CVaR aims to maximize the expected profits of the least profitable scenarios, thus

  13. Adaptive Harmonic Detection Control of Grid Interfaced Solar Photovoltaic Energy System with Power Quality Improvement

    NASA Astrophysics Data System (ADS)

    Singh, B.; Goel, S.

    2015-03-01

    This paper presents a grid interfaced solar photovoltaic (SPV) energy system with a novel adaptive harmonic detection control for power quality improvement at ac mains under balanced as well as unbalanced and distorted supply conditions. The SPV energy system is capable of compensation of linear and nonlinear loads with the objectives of load balancing, harmonics elimination, power factor correction and terminal voltage regulation. The proposed control increases the utilization of PV infrastructure and brings down its effective cost due to its other benefits. The adaptive harmonic detection control algorithm is used to detect the fundamental active power component of load currents which are subsequently used for reference source currents estimation. An instantaneous symmetrical component theory is used to obtain instantaneous positive sequence point of common coupling (PCC) voltages which are used to derive inphase and quadrature phase voltage templates. The proposed grid interfaced PV energy system is modelled and simulated in MATLAB Simulink and its performance is verified under various operating conditions.

  14. Introducing AC Inductive Reactance with a Power Tool

    ERIC Educational Resources Information Center

    Bryant, Wesley; Baker, Blane

    2016-01-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance…

  15. Watts Up? Pro AC Power Meter for Automated Energy Recording

    PubMed Central

    Hirst, Jason M.; Miller, Jonathan R.; Kaplan, Brent A.; Reed, Derek D.

    2013-01-01

    The purpose of the present paper is to review the Watts up? Pro AC power meter. Evaluations of the meter's reliability for measuring energy consumption by consumer electronics yielded acceptable levels of reliability. Implications and limitations for the use of this product in behavior analytic research and practice are discussed.

  16. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered slitlamp biomicroscope. 886.1850 Section 886.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... a thin, intense beam of light. (b) Classification. Class II....

  17. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered slitlamp biomicroscope. 886.1850 Section 886.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... microscope intended for use in eye examination that projects into a patient's eye through a control...

  18. ac power control in the Core Flow Test Loop

    SciTech Connect

    McDonald, D.W.

    1980-01-01

    This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. The initial considerations, design, and analysis of a closed-loop controller prototype are detailed. The design is then analyzed for improved performance possibilities and failure modes are investigated at length. A summary of the work completed to date and a proposed outline for continued development completes the report.

  19. Architecture of the Florida power grid as a complex network

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Gurfinkel, Aleks Jacob; Rikvold, Per Arne

    2014-05-01

    We study the Florida high-voltage power grid as a technological network embedded in space. Measurements of geographical lengths of transmission lines, the mixing of generators and loads, the weighted clustering coefficient, as well as the organization of edge conductance weights show a complex architecture quite different from random-graph models usually considered. In particular, we introduce a parametrized mixing matrix to characterize the mixing pattern of generators and loads in the Florida Grid, which is intermediate between the random mixing case and the semi-bipartite case where generator-generator transmission lines are forbidden. Our observations motivate an investigation of optimization (design) principles leading to the structural organization of power grids. We thus propose two network optimization models for the Florida Grid as a case study. Our results show that the Florida Grid is optimized not only by reducing the construction cost (measured by the total length of power lines), but also through reducing the total pairwise edge resistance in the grid, which increases the robustness of power transmission between generators and loads against random line failures. We then embed our models in spatial areas of different aspect ratios and study how this geometric factor affects the network structure, as well as the box-counting fractal dimension of the grids generated by our models.

  20. Enhanced INL Power Grid Test Bed Infrastructure – Phase I

    SciTech Connect

    Reid, Carol Ann; West, Grayson Shawn; McBride, Scott Alan

    2014-06-01

    Idaho National Laboratory (INL), a Department of Energy (DOE) laboratory, owns, operates, and maintains transmission and distribution power grid infrastructure to support the INL multi program mission. Sections of this power infrastructure, known as the INL Power Grid Test Bed, have been and are being used by government and industry to develop, demonstrate, and validate technologies for the modern grid, including smart grid, on a full scale utility test bed. INL’s power grid includes 61 miles of 140 MW, 138 kV rated electrical power transmission supplying seven main substations, each feeding a separate facility complex (or ‘city’) within the INL’s 890 square mile Site. This power grid is fed by three commercial utilities into the INL’s main control substation, but is operated independently from the commercial utility through its primary substation and command and control center. Within the INL complex, one of the seven complexes, the Critical Infrastructure Test Range Complex (CITRC), has been designated as the INL complex for supporting critical infrastructure research and testing. This complex includes its own substation and 13.8kV distribution network, all configurable and controlled by the INL research and development programs. Through investment partnership with the DOE Office of Electricity Delivery and Energy Reliability (DOE OE), INL is enhancing its existing distribution infrastructure to expand the types of testing that can be conducted and increase flexibility for testing configurations. The enhancement of the INL Power Grid Test Bed will enable development and full scale testing of smart-grid-related technologies and smart devices including testing interoperability, operational performance, reliability, and resiliency contribution at multiple distribution voltage classes, specifically 15kV, 25kV, and 35kV. The expected time frame for completion of the Phase I portion of the enhancement would be 4th quarter fiscal year (FY) 2015.

  1. Modified Perfect Harmonics Cancellation Control of a Grid Interfaced SPV Power Generation

    NASA Astrophysics Data System (ADS)

    Singh, B.; Shahani, D. T.; Verma, A. K.

    2015-03-01

    This paper deals with a grid interfaced solar photo voltaic (SPV) power generating system with modified perfect harmonic cancellation (MPHC) control for power quality improvement in terms of mitigation of the current harmonics, power factor correction, control of point of common coupling (PCC) voltage with reactive power compensation and load balancing in a three phase distribution system. The proposed grid interfaced SPV system consists of a SPV array, a dc-dc boost converter and a voltage source converter (VSC) used for the compensation of other connected linear and nonlinear loads at PCC. The reference grid currents are estimated using MPHC method and control signals are derived by using pulse width modulation (PWM) current controller of VSC. The SPV power is fed to the common dc bus of VSC and dc-dc boost converter using maximum power point tracking (MPPT). The dc link voltage of VSC is regulated by using dc voltage proportional integral (PI) controller. The analysis of the proposed SPV power generating system is carried out under dc/ac short circuit and severe SPV-SX and SPV-TX intrusion.

  2. 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

  3. Wind and Solar on the Power Grid: Myths and Misperceptions, Greening the Grid

    SciTech Connect

    Katz, Jessica; Denholm, Paul; Pless, Jacquelyn

    2015-05-01

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

  4. UPS with input commutation between ac and dc sources of power

    SciTech Connect

    Severinsky, A.J.

    1993-08-31

    An uninterruptible power supply is described, said power supply comprising: AC input terminal means for receiving a first AC voltage from an AC power source; DC input terminal means for receiving a first DC voltage from a DC power source; AC output terminal means for connecting to a load; converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage; switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means; inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range.

  5. Nonlinear control of voltage source converters in AC-DC power system.

    PubMed

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. PMID:24906895

  6. Off-grid power quality: Impacts, analysis and solutions

    NASA Astrophysics Data System (ADS)

    Gautam, Arjun

    Good power quality is a critical factor for the reliable operation of electrical loads in a power system. However, the current drawn by many electronic devices and non-linear loads are non-sinusoidal, which can result in a poor power quality, particularly in off-grid power systems. Poor power quality is characterized by electrical disturbances such as transients, sags, swells, harmonics and even interruptions in the power supply. Off-grid power systems worldwide struggle with system failures and equipment damage due to poor power quality. To better understand off-grid system failures and equipment damage issues, the current and voltage characteristics of a number of electrical devices in two off-grid homes, one using a pure sine wave inverter and the other using a modified sine wave inverter, were recorded with a Fluke 43B power quality analyzer, and the devices' impact on the power quality of the off-grid systems was analyzed. The off-grid power quality data were then compared with data from a grid-connected apartment, to help identify the issues that were specific to off-grid systems. The MATLAB/Simulink software was used to model and analyze power quality for additional configurations of the two off-grid systems mentioned above. Strategies to mitigate the worst power quality issues were selected based upon their function and cost, and a few were tested in an off-grid system. Selection of an inverter was found to be important because not all devices are supported by each type of inverter. For example, the refrigerator in the off-grid home with a modified sine wave inverter produced a significant amount of current and voltage harmonics far above standards. In fact, this type of inverter does not support a number of sensitive devices including motors, refrigerators, microwave ovens, fluorescent lights, battery chargers etc. The major issues for the degradation of power quality in the off-grid system using a pure sine wave inverter were the current harmonics

  7. Proposal of Smart Storage for Ubiquitous Power Grid

    NASA Astrophysics Data System (ADS)

    Ota, Yutaka; Taniguchi, Haruhito; Nakajima, Tatsuhito; Liyanage, Kithsiri M.; Baba, Junpei; Yokoyama, Akihiko

    Penetrating large amount of renewable energy sources into power system, battery energy storage performs an important role for smoothing their natural intermittency, ensuring grid-wide frequency stability, and suppressing voltage rise caused by reverse power flow. The ubiquitous power grid concept has been proposed as a smart grid in Japanese context, where the total battery capacity can be optimized by coordinating renewable energy sources, controllable distributed generators, and controllable loads on demand side, for example, heat pump based water heater with heat storage, and plug-in hybrid vehicle or electric vehicle with onboard battery, and so on. In this paper, we propose an autonomous distributed vehicle-to-grid (V2G) control scheme. The proposed V2G control has droop characteristics against power system frequency measurement at 200/100V plug-in terminal, and battery state-of-charge (SOC) is balanced within designable range by restraining V2G gain according to estimated SOC. Of course, the convenience for vehicle user is considered by V1G charge, which is one-way charging control for plug-out. Self terminal frequency measurement algorithm, model based battery SOC estimation method, and the proposed autonomous distributed V2G control are implemented to automotive power electronics circuit and electric control unit. These concepts are summarized as Smart Storage in ubiquitous power grid applications.

  8. Reliable, Efficient and Cost-Effective Electric Power Converter for Small Wind Turbines Based on AC-link Technology

    SciTech Connect

    Darren Hammell; Mark Holveck; DOE Project Officer - Keith Bennett

    2006-08-01

    Grid-tied inverter power electronics have been an Achilles heel of the small wind industry, providing opportunity for new technologies to provide lower costs, greater efficiency, and improved reliability. The small wind turbine market is also moving towards the 50-100kW size range. The unique AC-link power conversion technology provides efficiency, reliability, and power quality advantages over existing technologies, and Princeton Power will adapt prototype designs used for industrial asynchronous motor control to a 50kW small wind turbine design.

  9. Does the electric power grid need a room temperature superconductor?

    NASA Astrophysics Data System (ADS)

    Malozemoff, A. P.

    2013-11-01

    Superconductivity can revolutionize electric power grids, for example with high power underground cables to open urban power bottlenecks and fault current limiters to solve growing fault currents problems. Technology based on high temperature superconductor (HTS) wire is beginning to meet these critical needs. Wire performance is continually improving. For example, American Superconductor has recently demonstrated long wires with up to 500 A/cm-width at 77 K, almost doubling its previous production performance. But refrigeration, even at 77 K, is a complication, driving interest in discovering room temperature superconductors (RTS). Unfortunately, short coherence lengths and accelerated flux creep will make RTS applications unlikely. Existing HTS technology, in fact, offers a good compromise of relatively high operating temperature but not so high as to incur coherence-length and flux-creep limitations. So - no, power grids do not need RTS; existing HTS wire is proving to be what grids really need.

  10. Wide-area situation awareness in electric power grid

    NASA Astrophysics Data System (ADS)

    Greitzer, Frank L.

    2010-04-01

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

  11. Wide-area situation awareness in electric power grid

    SciTech Connect

    Greitzer, Frank L.

    2010-04-28

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

  12. Solar Power and the Electric Grid, Energy Analysis (Fact Sheet)

    SciTech Connect

    Not Available

    2010-03-01

    In today's electricity generation system, different resources make different contributions to the electricity grid. This fact sheet illustrates the roles of distributed and centralized renewable energy technologies, particularly solar power, and how they will contribute to the future electricity system. The advantages of a diversified mix of power generation systems are highlighted.

  13. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  14. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  15. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  16. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  17. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered...

  18. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered...

  19. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered...

  20. 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

  1. 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.

  2. Comparative analysis of existing models for power-grid synchronization

    NASA Astrophysics Data System (ADS)

    Nishikawa, Takashi; Motter, Adilson E.

    2015-01-01

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

  3. Preliminary study of AC power feeders for AGS booster

    SciTech Connect

    Meth, M.

    1992-07-17

    It has been proposed that the AGS Heavy Ion/Proton Booster be excited directly from the electric power distribution system without intervening an energy storage buffer such as an MG set or a magnetic energy buffer. The average power requirement of the AGS Booster is less than many single-loads presently housed on the lab site. However, the power swing will be the largest single pulsating load on the lab site. The large power swings will impact on the power grid producing utility-line disturbances such as voltage fluctuations and harmonic generation. Thus, it is necessary to carefully evaluate the quality of the electric power system resulting from the interconnection, such that the utility system is not degraded either on the lab site or at LILCO`s substation.

  4. Preliminary study of AC power feeders for AGS booster

    SciTech Connect

    Meth, M.

    1992-07-17

    It has been proposed that the AGS Heavy Ion/Proton Booster be excited directly from the electric power distribution system without intervening an energy storage buffer such as an MG set or a magnetic energy buffer. The average power requirement of the AGS Booster is less than many single-loads presently housed on the lab site. However, the power swing will be the largest single pulsating load on the lab site. The large power swings will impact on the power grid producing utility-line disturbances such as voltage fluctuations and harmonic generation. Thus, it is necessary to carefully evaluate the quality of the electric power system resulting from the interconnection, such that the utility system is not degraded either on the lab site or at LILCO's substation.

  5. A novel visualization technique for electric power grid analytics.

    PubMed

    Wong, Pak Chung; Schneider, Kevin; Mackey, Patrick; Foote, Harlan; Chin, George; Guttromson, Ross; Thomas, Jim

    2009-01-01

    The application of information visualization holds tremendous promise for the electric power industry, but its potential has so far not been sufficiently exploited by the visualization community. Prior work on visualizing electric power systems has been limited to depicting raw or processed information on top of a geographic layout. Little effort has been devoted to visualizing the physics of the power grids, which ultimately determines the condition and stability of the electricity infrastructure. Based on this assessment, we developed a novel visualization system prototype, GreenGrid, to explore the planning and monitoring of the North American Electricity Infrastructure. The paper discusses the rationale underlying the GreenGrid design, describes its implementation and performance details, and assesses its strengths and weaknesses against the current geographic-based power grid visualization. We also present a case study using GreenGrid to analyze the information collected moments before the last major electric blackout in the Western United States and Canada, and a usability study to evaluate the practical significance of our design in simulated real-life situations. Our result indicates that many of the disturbance characteristics can be readily identified with the proper form of visualization. PMID:19282548

  6. Protecting Intelligent Distributed Power Grids against Cyber Attacks

    SciTech Connect

    Dong Wei; Yan Lu; Mohsen Jafari; Paul Skare; Kenneth Rohde

    2010-12-31

    Like other industrial sectors, the electrical power industry is facing challenges involved with the increasing demand for interconnected operations and control. The electrical industry has largely been restructured due to deregulation of the electrical market and the trend of the Smart Grid. This moves new automation systems from being proprietary and closed to the current state of Information Technology (IT) being highly interconnected and open. However, while gaining all of the scale and performance benefits of IT, existing IT security challenges are acquired as well. The power grid automation network has inherent security risks due to the fact that the systems and applications for the power grid were not originally designed for the general IT environment. In this paper, we propose a conceptual layered framework for protecting power grid automation systems against cyber attacks. The following factors are taken into account: (1) integration with existing, legacy systems in a non-intrusive fashion; (2) desirable performance in terms of modularity, scalability, extendibility, and manageability; (3) alignment to the 'Roadmap to Secure Control Systems in the Energy Sector' and the future smart grid. The on-site system test of the developed prototype security system is briefly presented as well.

  7. Grid-scale fluctuations and forecast error in wind power

    NASA Astrophysics Data System (ADS)

    Bel, G.; Connaughton, C. P.; Toots, M.; Bandi, M. M.

    2016-02-01

    Wind power fluctuations at the turbine and farm scales are generally not expected to be correlated over large distances. When power from distributed farms feeds the electrical grid, fluctuations from various farms are expected to smooth out. Using data from the Irish grid as a representative example, we analyze wind power fluctuations entering an electrical grid. We find that not only are grid-scale fluctuations temporally correlated up to a day, but they possess a self-similar structure—a signature of long-range correlations in atmospheric turbulence affecting wind power. Using the statistical structure of temporal correlations in fluctuations for generated and forecast power time series, we quantify two types of forecast error: a timescale error ({e}τ ) that quantifies deviations between the high frequency components of the forecast and generated time series, and a scaling error ({e}\\zeta ) that quantifies the degree to which the models fail to predict temporal correlations in the fluctuations for generated power. With no a priori knowledge of the forecast models, we suggest a simple memory kernel that reduces both the timescale error ({e}τ ) and the scaling error ({e}\\zeta ).

  8. Power grid disturbances and polar cap index during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Stauning, Peter

    2013-06-01

    The strong geomagnetic storm in the evening of 30 October 2003 caused high-voltage power grid disturbances in Sweden that expanded to produce hour-long power line outage in Malmö located in the southern part of the country. This was not a unique situation. The geomagnetic storm on 13 March 1989 caused extensive disruptions of high-voltage power circuits especially in the Province of Quebec, Canada, but also to a lesser degree in Scandinavia. Similar events have occurred earlier, among others, during the great storms of 13-14 July 1982 and 8-9 February 1986. These high-voltage power grid disturbances were related to impulsive magnetic variations accompanying extraordinarily intense substorm events. The events were preceded by lengthy intervals of unusually high values of the Polar Cap (PC) index caused by enhanced transpolar ionospheric convection. The transpolar convection transports magnetic flux from the dayside to nightside which causes equatorward displacements of the region of auroral activity enabling the substorms to hit vital power grids. During the 30 October 2003 event the intense solar proton radiation disabled the ACE satellite observations widely used to provide forecast of magnetic storm events. Hence in this case the alarmingly high PC index could provide useful warning of the storm as a back-up of the missing ACE-based forecast. In further cases, monitoring the PC index level could provide supplementary storm warnings to the benefit of power grid operators.

  9. Stability of power grids: An overview

    NASA Astrophysics Data System (ADS)

    Gajduk, Andrej; Todorovski, Mirko; Kocarev, Ljupco

    2014-10-01

    Transient stability and steady-state (small signal) stability in power girds are reviewed. Transient stability concepts are illustrated with simple examples; in particular, we consider three methods for computing region of attraction: time-simulations, extended Lyapunov function, and sum of squares optimization method. We discuss steady state stability in power systems, and present an example of a feedback control via a communication network for the 10 Unit 39 Bus New England Test system.

  10. Techniques for Improving Filters in Power Grid Contingency Analysis

    SciTech Connect

    Adolf, Robert D.; Haglin, David J.; Halappanavar, Mahantesh; Chen, Yousu; Huang, Zhenyu

    2011-12-31

    In large-scale power transmission systems, predicting faults and preemptively taking corrective action to avoid them is essential to preventing rolling blackouts. The computational study of the constantly-shifting state of the power grid and its weaknesses is called contingency analysis. Multiple-contingency planning in the electrical grid is one example of a complex monitoring system where a full computational solution is operationally infeasible. We present a general framework for building and evaluating resource-aware models of filtering techniques for this type of monitoring.

  11. Demand Side Management in the Smart Grid: Information Processing for the Power Switch

    SciTech Connect

    Alizadeh, Mahnoosh; LI, Xiao; Wang, Zhifang; Scagilone, Anna; Melton, Ronald B.

    2012-09-01

    In this article we discuss the most recent developments in the area of load management, and consider possible interaction schemes of novel architectures with distributed energy resources (DER). In order to handle the challenges faced by tomorrow’s smart grid, which are caused by volatile load and generation profiles (from the large number of plug-in EVs and from renewable integration), the conventional grid operating principle of load-following needs to be changed into load-shaping or generation-following. Demand Side Management will be a most promising and powerful solution to the above challenges. However, many other issues such as load forecasting, pricing structure, market policy, renewable integration interface, and even the AC/DC implementation at the distribution side, need to be taken into the design in order to search for the most effective and applicable solution.

  12. Ultrafast Power Processor for Smart Grid Power Module Development

    SciTech Connect

    MAITRA, ARINDAM; LITWIN, RAY; lai, Jason; Syracuse, David

    2012-12-30

    This project’s goal was to increase the switching speed and decrease the losses of the power semiconductor devices and power switch modules necessary to enable Smart Grid energy flow and control equipment such as the Ultra-Fast Power Processor. The primary focus of this project involves exploiting the new silicon-based Super-GTO (SGTO) technology and build on prototype modules already being developed. The prototype super gate-turn-off thyristor (SGTO) has been tested fully under continuously conducting and double-pulse hard-switching conditions for conduction and switching characteristics evaluation. The conduction voltage drop measurement results indicate that SGTO has excellent conduction characteristics despite inconsistency among some prototype devices. Tests were conducted with two conditions: (1) fixed gate voltage and varying anode current condition, and (2) fixed anode current and varying gate voltage condition. The conduction voltage drop is relatively a constant under different gate voltage condition. In terms of voltage drop as a function of the load current, there is a fixed voltage drop about 0.5V under zero current condition, and then the voltage drop is linearly increased with the current. For a 5-kV voltage blocking device that may operate under 2.5-kV condition, the projected voltage drop is less than 2.5 V under 50-A condition, or 0.1%. If the device is adopted in a converter operating under soft-switching condition, then the converter can achieve an ultrahigh efficiency, typically above 99%. The two-pulse switching test results indicate that SGTO switching speed is very fast. The switching loss is relatively low as compared to that of the insulated-gate-bipolar-transistors (IGBTs). A special phenomenon needs to be noted is such a fast switching speed for the high-voltage switching tends to create an unexpected Cdv/dt current, which reduces the turn-on loss because the dv/dt is negative and increases the turn-off loss because the dv/dt is

  13. Decision making for best cogeneration power integration into a grid

    NASA Astrophysics Data System (ADS)

    Al Asmar, Joseph; Zakhia, Nadim; Kouta, Raed; Wack, Maxime

    2016-07-01

    Cogeneration systems are known to be efficient power systems for their ability to reduce pollution. Their integration into a grid requires simultaneous consideration of the economic and environmental challenges. Thus, an optimal cogeneration power are adopted to face such challenges. This work presents a novelty in selectinga suitable solution using heuristic optimization method. Its aim is to optimize the cogeneration capacity to be installed according to the economic and environmental concerns. This novelty is based on the sensitivity and data analysis method, namely, Multiple Linear Regression (MLR). This later establishes a compromise between power, economy, and pollution, which leads to find asuitable cogeneration power, and further, to be integrated into a grid. The data exploited were the results of the Genetic Algorithm (GA) multi-objective optimization. Moreover, the impact of the utility's subsidy on the selected power is shown.

  14. GridOPTICS(TM) A Novel Software Framework for Integrating Power Grid Data Storage, Management and Analysis

    SciTech Connect

    Gorton, Ian; Yin, Jian; Akyol, Bora A.; Ciraci, Selim; Critchlow, Terence; Liu, Yan; Gibson, Tara D.; Purohit, Sumit; Sharma, Poorva; Vlachopoulou, Maria

    2013-01-09

    This paper describes the architecture and design of GridOPTICSTM, a novel software framework to integrate a collection of software tools developed by PNNL’s Future Power Grid Initiative (FPGI) into a coherent, powerful operations and planning tool for the power grid of the future. GridOPTICSTM enables plug-and-play of various analysis, modeling and visualization software tools for fast and accurate control of the power grid. To bridge the data access for different control purposes, GridOPTICSTM provides a scalable and thin layer of event processing that hides the complexity of data storage and management. The initial prototype of GridOPTICSTM was demonstrated with several use cases from PNNL’s FPGI.

  15. Does topological information matter for power grid vulnerability?

    PubMed

    Ouyang, Min; Yang, Kun

    2014-12-01

    Power grids, which are playing an important role in supporting the economy of a region as well as the life of its citizens, could be attacked by terrorists or enemies to damage the region. Depending on different levels of power grid information collected by the terrorists, their attack strategies might be different. This paper groups power grid information into four levels: no information, purely topological information (PTI), topological information with generator and load nodes (GLNI), and full information (including component physical properties and flow parameters information), and then identifies possible attack strategies for each information level. Analyzing and comparing power grid vulnerability under these attack strategies from both terrorists' and utility companies' point of view give rise to an approach to quantify the relative values of these three types of information, including PTI, GLNI, and component parameter information (CPI). This approach can provide information regarding the extent to which topological information matters for power system vulnerability decisions. Taking several test systems as examples, results show that for small attacks with p ≤ 0.1, CPI matters the most; when taking attack cost into consideration and assuming that the terrorists take the optimum cost-efficient attack intensity, then CPI has the largest cost-based information value. PMID:25554041

  16. Does topological information matter for power grid vulnerability?

    NASA Astrophysics Data System (ADS)

    Ouyang, Min; Yang, Kun

    2014-12-01

    Power grids, which are playing an important role in supporting the economy of a region as well as the life of its citizens, could be attacked by terrorists or enemies to damage the region. Depending on different levels of power grid information collected by the terrorists, their attack strategies might be different. This paper groups power grid information into four levels: no information, purely topological information (PTI), topological information with generator and load nodes (GLNI), and full information (including component physical properties and flow parameters information), and then identifies possible attack strategies for each information level. Analyzing and comparing power grid vulnerability under these attack strategies from both terrorists' and utility companies' point of view give rise to an approach to quantify the relative values of these three types of information, including PTI, GLNI, and component parameter information (CPI). This approach can provide information regarding the extent to which topological information matters for power system vulnerability decisions. Taking several test systems as examples, results show that for small attacks with p ≤ 0.1, CPI matters the most; when taking attack cost into consideration and assuming that the terrorists take the optimum cost-efficient attack intensity, then CPI has the largest cost-based information value.

  17. A Sensemaking Perspective on Situation Awareness in Power Grid Operations

    SciTech Connect

    Greitzer, Frank L.; Schur, Anne; Paget, Mia L.; Guttromson, Ross T.

    2008-07-21

    With increasing complexity and interconnectivity of the electric power grid, the scope and complexity of grid operations continues to grow. New paradigms are needed to guide research to improve operations by enhancing situation awareness of operators. Research on human factors/situation awareness is described within a taxonomy of tools and approaches that address different levels of cognitive processing. While user interface features and visualization approaches represent the predominant focus of human factors studies of situation awareness, this paper argues that a complementary level, sensemaking, deserves further consideration by designers of decision support systems for power grid operations. A sensemaking perspective on situation aware-ness may reveal new insights that complement ongoing human factors research, where the focus of the investigation of errors is to understand why the decision makers experienced the situation the way they did, or why what they saw made sense to them at the time.

  18. Large-Scale Data Challenges in Future Power Grids

    SciTech Connect

    Yin, Jian; Sharma, Poorva; Gorton, Ian; Akyol, Bora A.

    2013-03-25

    This paper describes technical challenges in supporting large-scale real-time data analysis for future power grid systems and discusses various design options to address these challenges. Even though the existing U.S. power grid has served the nation remarkably well over the last 120 years, big changes are in the horizon. The widespread deployment of renewable generation, smart grid controls, energy storage, plug-in hybrids, and new conducting materials will require fundamental changes in the operational concepts and principal components. The whole system becomes highly dynamic and needs constant adjustments based on real time data. Even though millions of sensors such as phase measurement units (PMUs) and smart meters are being widely deployed, a data layer that can support this amount of data in real time is needed. Unlike the data fabric in cloud services, the data layer for smart grids must address some unique challenges. This layer must be scalable to support millions of sensors and a large number of diverse applications and still provide real time guarantees. Moreover, the system needs to be highly reliable and highly secure because the power grid is a critical piece of infrastructure. No existing systems can satisfy all the requirements at the same time. We examine various design options. In particular, we explore the special characteristics of power grid data to meet both scalability and quality of service requirements. Our initial prototype can improve performance by orders of magnitude over existing general-purpose systems. The prototype was demonstrated with several use cases from PNNL’s FPGI and was shown to be able to integrate huge amount of data from a large number of sensors and a diverse set of applications.

  19. The impact of model detail on power grid resilience measures

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  20. Grid-connected distributed solar power systems

    NASA Astrophysics Data System (ADS)

    Moyle, R.; Chernoff, H.; Schweizer, T.

    This paper discusses some important, though often ignored, technical and economic issues of distributed solar power systems: protection of the utility system and nonsolar customers requires suitable interfaced equipment. Purchase criteria must mirror reality; most analyses use life-cycle costing with low discount rates - most buyers use short payback periods. Distributing, installing, and marketing small, distributed solar systems is more costly than most analyses estimate. Results show that certain local conditions and uncommon purchase considerations can combine to make small, distributed solar power attractive, but lower interconnect costs (per kW), lower marketing and product distribution costs, and more favorable purchase criteria make large, centralized solar energy more attractive. Specifically, the value of dispersed solar systems to investors and utilities can be higher than $2000/kw. However, typical residential owners place a value of well under $1000 on the installed system.

  1. Resonant AC power system proof-of-concept test program

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.

    1986-01-01

    Proof-of-concept testing was performed on a 20-kHz, resonant power system breadboard from 1981 through 1985. The testing began with the evaluation of a single, 1.0-kW resonant inverter and progressed to the testing of breadboard systems with higher power levels and more capability. The final breadboard configuration tested was a 25.0-kW breadboard with six inverters providing power to three user-interface modules over a 50-meter, 20-kHz bus. The breadboard demonstrated the ability to synchronize multiple resonant inverters to power a common bus. Single-phase and three-phase 20-kHz power distribution was demonstrated. Simple conversion of 20-kHz to dc and variable-frequency ac was demonstrated as was bidirectional power flow between 20-kHz and dc. Steady state measurements of efficiency, power-factor tolerance, and conducted emissions and conducted susceptibility were made. In addition, transient responses were recorded for such conditions as start up, shut down, load changes. The results showed the 20-kHz resonant system to be a desirable technology for a spacecraft power management and distribution system with multiple users and a utility-type bus.

  2. Three-phase ac-to-ac series-resonant power converter with a reduced number of thyristors

    SciTech Connect

    Klaassens, J.B.; de Beer, F. )

    1991-07-01

    This paper reports that ac-ac series-resonant converters have been proven to be functional and useful. Power pulse modulation with internal frequencies of tens of kHz and suited for multikilowatt power levels is applied to a series-resonant converter system for generating synthesized multiphase bipolar waveforms with reversible power flow and flow distortion. The use of a series-resonant circuit for power transfer and control obtains natural current commutation of the thyristors and the prevention of excessive stresses on components. Switches are required which have bidirectional current conduction and voltage blocking ability. The conventional series-resonant ac-ac converter applies a total for 24 anti-parallel thyristors. An alternative circuit configuration for the series-resonant ac-ac converter with only 12 thyristors is also presented. The alternative power circuit has three neutrals, related to the polyphase source, the load and the converter, which may be interconnected. If they are connected, the high-frequency component of the source and load currents will flow through the connection between the neutrals. The test results of a converter system generating three-phase sinusoidal input and output waveforms have demonstrated the significant aspects of this type of power interfaces.

  3. Power Grid Data Analysis with R and Hadoop

    SciTech Connect

    Hafen, Ryan P.; Gibson, Tara D.; Kleese van Dam, Kerstin; Critchlow, Terence J.

    2014-01-01

    This book chapter presents an approach to analysis of large-scale time-series sensor information based on our experience with power grid data. We use the R-Hadoop Integrated Programming Environment (RHIPE) to analyze a 2TB data set and present code and results for this analysis.

  4. Statistical analysis of cascading failures in power grids

    SciTech Connect

    Chertkov, Michael; Pfitzner, Rene; Turitsyn, Konstantin

    2010-12-01

    We introduce a new microscopic model of cascading failures in transmission power grids. This model accounts for automatic response of the grid to load fluctuations that take place on the scale of minutes, when optimum power flow adjustments and load shedding controls are unavailable. We describe extreme events, caused by load fluctuations, which cause cascading failures of loads, generators and lines. Our model is quasi-static in the causal, discrete time and sequential resolution of individual failures. The model, in its simplest realization based on the Directed Current description of the power flow problem, is tested on three standard IEEE systems consisting of 30, 39 and 118 buses. Our statistical analysis suggests a straightforward classification of cascading and islanding phases in terms of the ratios between average number of removed loads, generators and links. The analysis also demonstrates sensitivity to variations in line capacities. Future research challenges in modeling and control of cascading outages over real-world power networks are discussed.

  5. Improved power control using optimal adjustable coefficients for three-phase photovoltaic inverter under unbalanced grid voltage.

    PubMed

    Wang, Qianggang; Zhou, Niancheng; Lou, Xiaoxuan; Chen, Xu

    2014-01-01

    Unbalanced grid faults will lead to several drawbacks in the output power quality of photovoltaic generation (PV) converters, such as power fluctuation, current amplitude swell, and a large quantity of harmonics. The aim of this paper is to propose a flexible AC current generation method by selecting coefficients to overcome these problems in an optimal way. Three coefficients are brought in to tune the output current reference within the required limits of the power quality (the current harmonic distortion, the AC current peak, the power fluctuation, and the DC voltage fluctuation). Through the optimization algorithm, the coefficients can be determined aiming to generate the minimum integrated amplitudes of the active and reactive power references with the constraints of the inverter current and DC voltage fluctuation. Dead-beat controller is utilized to track the optimal current reference in a short period. The method has been verified in PSCAD/EMTDC software. PMID:25243215

  6. Improved Power Control Using Optimal Adjustable Coefficients for Three-Phase Photovoltaic Inverter under Unbalanced Grid Voltage

    PubMed Central

    Wang, Qianggang; Zhou, Niancheng; Lou, Xiaoxuan; Chen, Xu

    2014-01-01

    Unbalanced grid faults will lead to several drawbacks in the output power quality of photovoltaic generation (PV) converters, such as power fluctuation, current amplitude swell, and a large quantity of harmonics. The aim of this paper is to propose a flexible AC current generation method by selecting coefficients to overcome these problems in an optimal way. Three coefficients are brought in to tune the output current reference within the required limits of the power quality (the current harmonic distortion, the AC current peak, the power fluctuation, and the DC voltage fluctuation). Through the optimization algorithm, the coefficients can be determined aiming to generate the minimum integrated amplitudes of the active and reactive power references with the constraints of the inverter current and DC voltage fluctuation. Dead-beat controller is utilized to track the optimal current reference in a short period. The method has been verified in PSCAD/EMTDC software. PMID:25243215

  7. PVUSA experience with power conversion for grid-connected photovoltaic systems

    SciTech Connect

    Stolte, W.

    1995-11-01

    The Photovoltaics for Utility Scale Application (PVUSA) project was established to demonstrate photovoltaic (PV) systems in grid-connected utility applications. One of PVUSA`s key objectives is to evaluate the performance, reliability, and cost of the PV balance of system (BOS). Power conditioning units (PCUs) are the interface between the dc PV arrays and the ac utility lines, and have proved to be the most critical element in grid-connected PV systems. There are five different models of PCUs at PVUSA`s Davis and Kerman sites. This report describes the design, testing, performance characteristics, and maintenance history of each of these PCUs. PVUSA required PCUs in the power range 25 kW to 500 kW which could operate automatically and reliably under changing conditions of sunlight and changing conditions on the utility grid. Although a number of manufacturers can provide PCUs in this power range, none of these PCUs have been produced in sufficient quantity to allow refinement of a particular model into the highly reliable unit needed for long-term, unattended operation. Factory tests were useful but limited by the inability to test under full power and changing power conditions. The inability to completely test PCUs at the factory resulted in difficulty during startup, field testing, and subsequent operation. PVUSA has made significant progress in understanding the requirements for PCUs in grid-connected PV applications and improving field performance. This record of PVUSA`s experience with a variety of PCUs is intended to help utilities and their suppliers identify and retain the good performance characteristics of PCUs, and to make improvements where necessary to meet the needs of utilities.

  8. A Bidirectional High-Power-Quality Grid Interface With a Novel Bidirectional Noninverted Buck Boost Converter for PHEVs

    SciTech Connect

    Onar, Omer C

    2012-01-01

    Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on two major thrust areas of PHEVs. First, it introduces a grid-friendly bidirectional alternating current/direct current ac/dc dc/ac rectifier/inverter for facilitating vehicle-to-grid (V2G) integration of PHEVs. Second, it presents an integrated bidirectional noninverted buck boost converter that interfaces the energy storage device of the PHEV to the dc link in both grid-connected and driving modes. The proposed bidirectional converter has minimal grid-level disruptions in terms of power factor and total harmonic distortion, with less switching noise. The integrated bidirectional dc/dc converter assists the grid interface converter to track the charge/discharge power of the PHEV battery. In addition, while driving, the dc/dc converter provides a regulated dc link voltage to the motor drive and captures the braking energy during regenerative braking.

  9. Transient Stability of the Grid with a Wind Power Plant

    SciTech Connect

    Muljadi, E.; Nguyen, Tony B.; Pai, M. A.

    2009-03-15

    This paper reports on an investigation of the impact of wind power plant penetration on the transient stability of the grid. Transient stability for different faults is investigated via simulation. A wind power plant with 22 turbines operated in variable speed mode will be used as the subject of the study. As a comparison, we replace the wind power plant with a conventional wind power plant (synchronous generator) and compare the results for the same faults. We also consider the effect of different locations.

  10. Space weather and power grids: findings and outlook

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  11. An integrated security framework for GOSS power grid analytics platform

    SciTech Connect

    Gibson, Tara D.; Ciraci, Selim; Sharma, Poorva; Allwardt, Craig H.; Rice, Mark J.; Akyol, Bora A.

    2014-06-23

    In power grid operations, security is an essential component for any middleware platform. Security protects data against unwanted access as well as cyber attacks. GridOpticsTM Software System (GOSS) is an open source power grid analytics platform that facilitates ease of access between applications and data sources and promotes development of advanced analytical applications. GOSS contains an API that abstracts many of the difficulties in connecting to various heterogeneous data sources. A number of applications and data sources have already been implemented to demonstrate functionality and ease of use. A security framework has been implemented which leverages widely accepted, robust JavaTM security tools in a way such that they can be interchanged as needed. This framework supports the complex fine-grained, access control rules identified for the diverse data sources already in GOSS. Performance and reliability are also important considerations in any power grid architecture. An evaluation is done to determine the overhead cost caused by security within GOSS and ensure minimal impact to performance.

  12. 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.

  13. Value of Faster Computation for Power Grid Operation

    SciTech Connect

    Chen, Yousu; Huang, Zhenyu; Elizondo, Marcelo A.

    2012-09-30

    As a result of the grid evolution meeting the information revolution, the power grid is becoming far more complex than it used to be. How to feed data in, perform analysis, and extract information in a real-time manner is a fundamental challenge in today’s power grid operation, not to mention the significantly increased complexity in the smart grid environment. Therefore, high performance computing (HPC) becomes one of the advanced technologies used to meet the requirement of real-time operation. This paper presents benefit case studies to show the value of fast computation for operation. Two fundamental operation functions, state estimation (SE) and contingency analysis (CA), are used as examples. In contrast with today’s tools, fast SE can estimate system status in a few seconds—comparable to measurement cycles. Fast CA can solve more contingencies in a shorter period, reducing the possibility of missing critical contingencies. The benefit case study results clearly show the value of faster computation for increasing the reliability and efficiency of power system operation.

  14. QPSK modulation for AC-power-signal-biased visible light communication system

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Feng; Yeh, Chien-Hung; Chow, Chi-Wai; Liu, Yang

    2013-01-01

    With the integration of light emitting diode (LED), visible light communication (VLC) can provide wireless communication link using the lightning system. Due to the consideration of power efficiency, AC-LED has the design of reducing energy waste with alternating current from the power outlet. In this work, we propose an AC-power-signalbiased system that provides communication on both DC-LED and AC-LED. The bias circuit is designed to combine ACpower signal and the message signal with QPSK format. This driving scheme needs no AC-to-DC converters and it is suitable for driving AC LED. Synchronization is completed to avoid threshold effect of LED.

  15. Accessing Wind Tunnels From NASA's Information Power Grid

    NASA Technical Reports Server (NTRS)

    Becker, Jeff; Biegel, Bryan (Technical Monitor)

    2002-01-01

    The NASA Ames wind tunnel customers are one of the first users of the Information Power Grid (IPG) storage system at the NASA Advanced Supercomputing Division. We wanted to be able to store their data on the IPG so that it could be accessed remotely in a secure but timely fashion. In addition, incorporation into the IPG allows future use of grid computational resources, e.g., for post-processing of data, or to do side-by-side CFD validation. In this paper, we describe the integration of grid data access mechanisms with the existing DARWIN web-based system that is used to access wind tunnel test data. We also show that the combined system has reasonable performance: wind tunnel data may be retrieved at 50Mbits/s over a 100 base T network connected to the IPG storage server.

  16. Power Prediction in Smart Grids with Evolutionary Local Kernel Regression

    NASA Astrophysics Data System (ADS)

    Kramer, Oliver; Satzger, Benjamin; Lässig, Jörg

    Electric grids are moving from a centralized single supply chain towards a decentralized bidirectional grid of suppliers and consumers in an uncertain and dynamic scenario. Soon, the growing smart meter infrastructure will allow the collection of terabytes of detailed data about the grid condition, e.g., the state of renewable electric energy producers or the power consumption of millions of private customers, in very short time steps. For reliable prediction strong and fast regression methods are necessary that are able to cope with these challenges. In this paper we introduce a novel regression technique, i.e., evolutionary local kernel regression, a kernel regression variant based on local Nadaraya-Watson estimators with independent bandwidths distributed in data space. The model is regularized with the CMA-ES, a stochastic non-convex optimization method. We experimentally analyze the load forecast behavior on real power consumption data. The proposed method is easily parallelizable, and therefore well appropriate for large-scale scenarios in smart grids.

  17. AN INTELLIGENT SENSOR FRAMEWORK FOR THE POWER GRID

    SciTech Connect

    Akyol, Bora A.; Haack, Jereme N.; Tews, Cody W.; Carpenter, Brandon J.; Kulkarni, Anand V.; Craig, Philip A.

    2011-08-10

    The number of sensors connected to the electric power system is expected to grow by several orders of magnitude by 2020. However, the information networks which will transmit and analyze the resulting data are ill-equipped to handle the resulting volume with reliable real-time delivery. Without the ability to manage and use this data, deploying sensors such as phasor measurement units in the transmission system and smart meters in the distribution system will not result in the desired improvements in the power grid. The ability to exploit the massive data being generated by new sensors would allow for more efficient flow of power and increased survivability of the grid. Additionally, the power systems of today are not capable of managing two-way power flow to accommodate distributed generation capabilities due to concerns about system stability and lack of system flexibility. The research that we are performing creates a framework to add 'intelligence' to the sensors and actuators being used today in the electric power system. Sensors that use our framework will be capable of sharing information through the various layers of the electric power system to enable two-way information flow to help facilitate integration of distributed resources. Several techniques are considered including use of peer-to-peer communication as well as distributed agents.

  18. Custom Sky-Image Mosaics from NASA's Information Power Grid

    NASA Technical Reports Server (NTRS)

    Jacob, Joseph; Collier, James; Craymer, Loring; Curkendall, David

    2005-01-01

    yourSkyG is the second generation of the software described in yourSky: Custom Sky-Image Mosaics via the Internet (NPO-30556), NASA Tech Briefs, Vol. 27, No. 6 (June 2003), page 45. Like its predecessor, yourSkyG supplies custom astronomical image mosaics of sky regions specified by requesters using client computers connected to the Internet. Whereas yourSky constructs mosaics on a local multiprocessor system, yourSkyG performs the computations on NASA s Information Power Grid (IPG), which is capable of performing much larger mosaicking tasks. (The IPG is high-performance computation and data grid that integrates geographically distributed 18 NASA Tech Briefs, September 2005 computers, databases, and instruments.) A user of yourSkyG can specify parameters describing a mosaic to be constructed. yourSkyG then constructs the mosaic on the IPG and makes it available for downloading by the user. The complexities of determining which input images are required to construct a mosaic, retrieving the required input images from remote sky-survey archives, uploading the images to the computers on the IPG, performing the computations remotely on the Grid, and downloading the resulting mosaic from the Grid are all transparent to the user

  19. A distributed power market for the Smart Grid

    NASA Astrophysics Data System (ADS)

    McCulloch, Ryan James

    To address the challenges of resource allocation in the Smart Electrical Grid a new power market is proposed. A distributed and autonomous contract net based market system in which participants, represented by the agents, engage in two distinct yet interconnected markets in order to determine resource allocation. Key to this proposed design is the 2 market structure which separates negotiations between consumers and reliable generation from negotiations between consumers and intermittent energy resources. The first or primary market operates as a first price sealed bid reverse auction while the second or secondary market utilizes a uniform price auction. In order to evaluate this new market a simulator is developed and the market is modeled and tested within it. The results of these tests indicate that the proposed design is an effective method of allocating electrical grid resources amongst consumers, generators, and intermittent energy resources with some feasibility and scalability limitations.

  20. Enhancing synchronization stability in a multi-area power grid.

    PubMed

    Wang, Bing; Suzuki, Hideyuki; Aihara, Kazuyuki

    2016-01-01

    Maintaining a synchronous state of generators is of central importance to the normal operation of power grids, in which many networks are generally interconnected. In order to understand the condition under which the stability can be optimized, it is important to relate network stability with feedback control strategies as well as network structure. Here, we present a stability analysis on a multi-area power grid by relating it with several control strategies and topological design of network structure. We clarify the minimal feedback gain in the self-feedback control, and build the optimal communication network for the local and global control strategies. Finally, we consider relationship between the interconnection pattern and the synchronization stability; by optimizing the network interlinks, the obtained network shows better synchronization stability than the original network does, in particular, at a high power demand. Our analysis shows that interlinks between spatially distant nodes will improve the synchronization stability. The results seem unfeasible to be implemented in real systems but provide a potential guide for the design of stable power systems. PMID:27225708

  1. Enhancing synchronization stability in a multi-area power grid

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Suzuki, Hideyuki; Aihara, Kazuyuki

    2016-05-01

    Maintaining a synchronous state of generators is of central importance to the normal operation of power grids, in which many networks are generally interconnected. In order to understand the condition under which the stability can be optimized, it is important to relate network stability with feedback control strategies as well as network structure. Here, we present a stability analysis on a multi-area power grid by relating it with several control strategies and topological design of network structure. We clarify the minimal feedback gain in the self-feedback control, and build the optimal communication network for the local and global control strategies. Finally, we consider relationship between the interconnection pattern and the synchronization stability; by optimizing the network interlinks, the obtained network shows better synchronization stability than the original network does, in particular, at a high power demand. Our analysis shows that interlinks between spatially distant nodes will improve the synchronization stability. The results seem unfeasible to be implemented in real systems but provide a potential guide for the design of stable power systems.

  2. Enhancing synchronization stability in a multi-area power grid

    PubMed Central

    Wang, Bing; Suzuki, Hideyuki; Aihara, Kazuyuki

    2016-01-01

    Maintaining a synchronous state of generators is of central importance to the normal operation of power grids, in which many networks are generally interconnected. In order to understand the condition under which the stability can be optimized, it is important to relate network stability with feedback control strategies as well as network structure. Here, we present a stability analysis on a multi-area power grid by relating it with several control strategies and topological design of network structure. We clarify the minimal feedback gain in the self-feedback control, and build the optimal communication network for the local and global control strategies. Finally, we consider relationship between the interconnection pattern and the synchronization stability; by optimizing the network interlinks, the obtained network shows better synchronization stability than the original network does, in particular, at a high power demand. Our analysis shows that interlinks between spatially distant nodes will improve the synchronization stability. The results seem unfeasible to be implemented in real systems but provide a potential guide for the design of stable power systems. PMID:27225708

  3. PMU Placement for Enhancing Dynamic Observability of a Power Grid

    SciTech Connect

    Du, Pengwei; Huang, Zhenyu; Diao, Ruisheng; Lee, Barry; Anderson, Kevin K.

    2010-09-27

    Power grids are operated in an increasingly complicated environment. However, operators lack effective and accurate tools for real-time monitoring and control of power systems. The U.S. Department of Energy, along with several utilities and system operators, is making a major $108 million investment in the Western Interconnection for phasor measurement unit (PMU) installation and phasor application development. This phasor measurement network opens up many opportunities for the estimation and prediction of power system states in real time, which enable operators to evaluate the system dynamic security in advance and allow them more time to respond to disturbances. Kalman filter based dynamic state estimation offers a solution suitable for this purpose. Our work indicates that the performance of Kalman filters in dynamic state estimation would degrade if PMU measurements cannot adequately capture the system dynamics. This paper develops a framework to identify how to place PMUs to improve dynamic observability of the power grid. Simulation results validate the concept, and the guidelines for PMU placement are derived.

  4. Intelligence by design in an entropic power grid

    NASA Astrophysics Data System (ADS)

    Negrete-Pincetic, Matias Alejandro

    In this work, the term Entropic Grid is coined to describe a power grid with increased levels of uncertainty and dynamics. These new features will require the reconsideration of well-established paradigms in the way of planning and operating the grid and its associated markets. New tools and models able to handle uncertainty and dynamics will form the required scaffolding to properly capture the behavior of the physical system, along with the value of new technologies and policies. The leverage of this knowledge will facilitate the design of new architectures to organize power and energy systems and their associated markets. This work presents several results, tools and models with the goal of contributing to that design objective. A central idea of this thesis is that the definition of products is critical in electricity markets. When markets are constructed with appropriate product definitions in mind, the interference between the physical and the market/financial systems seen in today's markets can be reduced. A key element of evaluating market designs is understanding the impact that salient features of an entropic grid---uncertainty, dynamics, constraints---can have on the electricity markets. Dynamic electricity market models tailored to capture such features are developed in this work. Using a multi-settlement dynamic electricity market, the impact of volatility is investigated. The results show the need to implement policies and technologies able to cope with the volatility of renewable sources. Similarly, using a dynamic electricity market model in which ramping costs are considered, the impacts of those costs on electricity markets are investigated. The key conclusion is that those additional ramping costs, in average terms, are not reflected in electricity prices. These results reveal several difficulties with today's real-time markets. Elements of an alternative architecture to organize these markets are also discussed.

  5. A Stochastic Power Network Calculus for Integrating Renewable Energy Sources into the Power Grid

    SciTech Connect

    Wang, K; Ciucu, F; Lin, C; Low, SH

    2012-07-01

    Renewable energy such as solar and wind generation will constitute an important part of the future grid. As the availability of renewable sources may not match the load, energy storage is essential for grid stability. In this paper we investigate the feasibility of integrating solar photovoltaic (PV) panels and wind turbines into the grid by also accounting for energy storage. To deal with the fluctuation in both the power supply and demand, we extend and apply stochastic network calculus to analyze the power supply reliability with various renewable energy configurations. To illustrate the validity of the model, we conduct a case study for the integration of renewable energy sources into the power system of an island off the coast of Southern California. In particular, we asses the power supply reliability in terms of the average Fraction of Time that energy is Not-Served (FTNS).

  6. Novel DC ring topology and protection system - a comprehensive solution for mega city power grids

    NASA Astrophysics Data System (ADS)

    Haj-Maharsi, Mohamed Yassine

    2009-07-01

    The development of mega cities leads to increased load concentration and brings additional challenges to managing the electrical grid while keeping power available for critical loads. Techniques using FACTS devices are being applied to alleviate power management difficulties and to confine faults in their originating areas in order to limit the risk of cascading failures in the grid. The addition of many FACTS devices often results in control and protection coordination difficulties, power oscillations between connected networks, subsynchronous resonance problems, and torsional interactions with nearby generator units. The most effective solution is obtained when the individual AC subsystems representing sources and loads are decoupled so a fault in a given subsystem is not propagated to another subsystem. This solution can be achieved by the deployment of a DC system where power sources and loads are connected to the DC bus through voltage source converters. For a mega city, this would be conceived as a DC ring feeding multiple loads and connected to remote and local power sources. Unfortunately, the lack of fast DC circuit breakers has been one of the key issues affecting extensive applications of DC systems with common DC buses; a DC fault would discharge all the capacitors of the DC bus and cause delays in system recovery and possibly a wide system collapse. In this research, I provide a comprehensive solution to mega city power grid problems by proposing a DC system topology that enables grid expansions without affecting existing protection settings or changing existing AC breaker ratings. I also propose the means for protecting the DC system by designing a fast DC breaker and developing a control algorithm capable of isolating DC faults without blocking converter stations or depleting DC bus capacitors. My contribution is three folds: (1) I modeled and simulated Shanghai power grid and performed a study to identify short circuit and voltage stability problems

  7. Application of Cray XMT for Power Grid Contingency Selection

    SciTech Connect

    Chen, Yousu; Jin, Shuangshuang; Chavarría-Miranda, Daniel; Huang, Zhenyu

    2009-05-07

    Contingency analysis is a key function to assess the impact of various combinations of power system component failures. It involves combinatorial numbers of contingencies which exceed the capability of even very large supercomputing platforms. Therefore, it is critical to select contingency cases within the constraint of computing power. This paper presents a contingency selection method employing graph theory (edge betweenness centrality) to power grid weighted graphs to remove low-impact components. The parallel implementation of the method was successfully carried out on the Cray XMT machine. The implementation takes advantage of the superior capabilities of the Cray XMT for graph-based problems and its programming features. This paper presents the performance scalability of Cray XMT and comparison with a cache-based, shared-memory machine.

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

    NASA Astrophysics Data System (ADS)

    Aula, Fadhil Toufick

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

  9. Optimal reactive power control of grid connected photovoltaic resources

    NASA Astrophysics Data System (ADS)

    Trimble, Joshua Ryan

    As more photovoltaic distributed generation resources are installed on distribution power systems, selective control of the inverters connecting the DC power sources presents the opportunity to supply both real and reactive power at the point of common coupling. This thesis presents a simulated distribution system with individually controlled PV resources with the objective of minimizing total system losses while operating at the maximum power point and below the simulated rating of the associated inverters. The control strategy assumes the characteristics of the distribution system are known and solves for the optimal power flow operating point. The ability of each PV source to provide real and reactive power varies instantaneously as irradiance changes, so the operating point for each resource must be constantly recalculated and adjusted. The assumption of known system paramaters can be justified in a SmartGrid context, and a solution based on overall system power flow should be considered as a benchmark for any other state estimation or local control approaches.

  10. Residential photovoltaic power conditioning technology for grid connected applications

    NASA Technical Reports Server (NTRS)

    Key, T. S.; Klein, J. W.

    1982-01-01

    Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.

  11. Multipurpose Power Converter for Non-Grid-Connected Microsystems

    NASA Astrophysics Data System (ADS)

    Vovos, Panagis N.; Georgakas, Konstantinos G.

    2015-04-01

    The aim of this paper is to present a multipurpose converter, appropriate for non-grid-connected microsystems, which are prone to harmonic distortion. The converter suppresses harmonics by injecting mirror harmonics in the modulation stage. An important property is that it continuously monitors and significantly reduces the harmonic content without the use of active or passive low-frequency filters. This is under constant switching frequency, no matter if the harmonics are mainly created by the source, the loads or even its own operation. The converter is regulating output voltage using typical fuzzy control. The two types of control (harmonic and voltage) do not seem to affect each other during operation. Furthermore, it can supply either dc or ac loads from a dc source. The versatility of the converter is a useful property for remote or mobile micropower systems, where neither sources nor loads are of a single type. The converter has been tested successfully for a combination of harmonic-injecting electric appliances and various load step changes.

  12. Machine learning for the New York City power grid.

    PubMed

    Rudin, Cynthia; Waltz, David; Anderson, Roger N; Boulanger, Albert; Salleb-Aouissi, Ansaf; Chow, Maggie; Dutta, Haimonti; Gross, Philip N; Huang, Bert; Ierome, Steve; Isaac, Delfina F; Kressner, Arthur; Passonneau, Rebecca J; Radeva, Axinia; Wu, Leon

    2012-02-01

    Power companies can benefit from the use of knowledge discovery methods and statistical machine learning for preventive maintenance. We introduce a general process for transforming historical electrical grid data into models that aim to predict the risk of failures for components and systems. These models can be used directly by power companies to assist with prioritization of maintenance and repair work. Specialized versions of this process are used to produce 1) feeder failure rankings, 2) cable, joint, terminator, and transformer rankings, 3) feeder Mean Time Between Failure (MTBF) estimates, and 4) manhole events vulnerability rankings. The process in its most general form can handle diverse, noisy, sources that are historical (static), semi-real-time, or realtime, incorporates state-of-the-art machine learning algorithms for prioritization (supervised ranking or MTBF), and includes an evaluation of results via cross-validation and blind test. Above and beyond the ranked lists and MTBF estimates are business management interfaces that allow the prediction capability to be integrated directly into corporate planning and decision support; such interfaces rely on several important properties of our general modeling approach: that machine learning features are meaningful to domain experts, that the processing of data is transparent, and that prediction results are accurate enough to support sound decision making. We discuss the challenges in working with historical electrical grid data that were not designed for predictive purposes. The “rawness” of these data contrasts with the accuracy of the statistical models that can be obtained from the process; these models are sufficiently accurate to assist in maintaining New York City’s electrical grid. PMID:21576741

  13. Detection of Power Grid Harmonic Pollution Sources based on Upgraded Power Meters

    NASA Astrophysics Data System (ADS)

    Petković, Predrag; Stevanović, Dejan

    2014-05-01

    The paper suggests a new and efficient method for location of nonlinear loads on a grid. It is based on measuring of distortion power. The paper reviews different definitions of distortion power and proves that the method is feasible independently on particular definition. The obtained results of simulation and measurement confirm the effectiveness and applicability of the method. The proposed solution is suitable for software update of existing electronic power-meters or can be implement as hardware upgrade.

  14. Building blocks of the basin stability of power grids

    NASA Astrophysics Data System (ADS)

    Kim, Heetae; Lee, Sang Hoon; Holme, Petter

    2016-06-01

    Given a power grid and a transmission (coupling) strength, basin stability is a measure of synchronization stability for individual nodes. Earlier studies have focused on the basin stability's dependence of the position of the nodes in the network for single values of transmission strength. Basin stability grows from zero to one as transmission strength increases, but often in a complex, nonmonotonous way. In this study, we investigate the entire functional form of the basin stability's dependence on transmission strength. To be able to perform a systematic analysis, we restrict ourselves to small networks. We scan all isomorphically distinct networks with an equal number of power producers and consumers of six nodes or less. We find that the shapes of the basin stability fall into a few, rather well-defined classes, that could be characterized by the number of edges and the betweenness of the nodes, whereas other network positional quantities matter less.

  15. Intelligent sensor and controller framework for the power grid

    SciTech Connect

    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.

  16. Methods for Procuring Power System Flexibility, Greening the Grid

    SciTech Connect

    Katz, Jessica; Cochran, Jaquelin; Miller, Mackay

    2015-05-01

    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. This document, part of a Greening the Grid toolkit, introduces administrative and incentive-based mechanisms for procuring a cost-effective mix of flexibility sources.

  17. Geomagnetically Induced Currents and Impact on Power Grids

    NASA Astrophysics Data System (ADS)

    Pulkkinen, A. A.

    2015-12-01

    Geomagnetically induced currents (GIC) flowing in long manmade conductor systems have become one of the main space weather concerns. The potential for widespread problems in operating high-voltage power transmission systems during major geomagnetic storms has prompted increasing federal regulatory, science, industry and public interest in the problem. The impact caused by extreme storm events has been of special interest and consequently much of the recent GIC research has been focused on defining extreme GIC event scenarios and quantifying the corresponding transmission system response. In addition, there is an elevated need for developing next generation GIC prediction products for the power industry. In this presentation, I will discuss the key scientific concepts pertaining to GIC and provide a brief review of the recent progress in developing extreme storm scenarios and new predictive techniques. Much of the recent progress in understanding GIC and its impact on power grids has resulted from improved scientific community-power industry interactions. The common language and information exchange interfaces established between the two communities have led to significant progress in transitioning scientific knowledge into detailed impacts analyses. I will provide a few personal reflections on the interactions with the power industry. We also face a number of future challenges in specifying GIC, for example, in terms of more realistic modeling of the three-dimensional geomagnetic induction process. I will discuss briefly some of these future challenges.

  18. Design and Control Implementation of AC Electric Power Steering System Test Bench*

    NASA Astrophysics Data System (ADS)

    Zhang, Weidong; Ai, Yibo

    Using AC motor is an important development trend of electric power steering system, and in this paper, we proposed a design of AC electric power steering system test bench. The paper introduced the bench structure, working principle and main components selection first, and then given the implementation scheme of test bench's three functions: simulation of the road resistance, power assistant control and data acquisition. The test results showed the feasibility of the test bench.

  19. Power Grid Maintenance Scheduling Intelligence Arrangement Supporting System Based on Power Flow Forecasting

    NASA Astrophysics Data System (ADS)

    Xie, Chang; Wen, Jing; Liu, Wenying; Wang, Jiaming

    With the development of intelligent dispatching, the intelligence level of network control center full-service urgent need to raise. As an important daily work of network control center, the application of maintenance scheduling intelligent arrangement to achieve high-quality and safety operation of power grid is very important. By analyzing the shortages of the traditional maintenance scheduling software, this paper designs a power grid maintenance scheduling intelligence arrangement supporting system based on power flow forecasting, which uses the advanced technologies in maintenance scheduling, such as artificial intelligence, online security checking, intelligent visualization techniques. It implements the online security checking of maintenance scheduling based on power flow forecasting and power flow adjusting based on visualization, in order to make the maintenance scheduling arrangement moreintelligent and visual.

  20. Power fluctuation reduction methodology for the grid-connected renewable power systems

    NASA Astrophysics Data System (ADS)

    Aula, Fadhil T.; Lee, Samuel C.

    2013-04-01

    This paper presents a new methodology for eliminating the influence of the power fluctuations of the renewable power systems. The renewable energy, which is to be considered an uncertain and uncontrollable resource, can only provide irregular electrical power to the power grid. This irregularity creates fluctuations of the generated power from the renewable power systems. These fluctuations cause instability to the power system and influence the operation of conventional power plants. Overall, the power system is vulnerable to collapse if necessary actions are not taken to reduce the impact of these fluctuations. This methodology aims at reducing these fluctuations and makes the generated power capability for covering the power consumption. This requires a prediction tool for estimating the generated power in advance to provide the range and the time of occurrence of the fluctuations. Since most of the renewable energies are weather based, as a result a weather forecast technique will be used for predicting the generated power. The reduction of the fluctuation also requires stabilizing facilities to maintain the output power at a desired level. In this study, a wind farm and a photovoltaic array as renewable power systems and a pumped-storage and batteries as stabilizing facilities are used, since they are best suitable for compensating the fluctuations of these types of power suppliers. As an illustrative example, a model of wind and photovoltaic power systems with battery energy and pumped hydro storage facilities for power fluctuation reduction is included, and its power fluctuation reduction is verified through simulation.

  1. Study and Analysis on Technology and Development of Information Network of Rural Power Grid

    NASA Astrophysics Data System (ADS)

    Li, Weiying

    This paper describes the technology and transferring mode of rural power grid’s information network, analyses technology of communication system of electric power grid in rural area, chooses a new develop direction of technique based on the business needs and trend of rural power grids, and gives a route for development.

  2. Measurement of klystron phase modulation due to ac-powered filaments

    NASA Technical Reports Server (NTRS)

    Finnegan, E. J.

    1977-01-01

    A technique for determining the intermodulation components in the RF spectrum of the S-band radar transmitter generated by having the klystron filaments heated by 400-Hz ac power is described. When the klystron is being operated with 400-Hz (ac) on the filament, the IPM is buried in the 400-Hz equipment interference noise. The modulation sidebands were separated and identified and found to be-67 db below the main carrier. This is well below the transmitter specifications, and operating the filaments on ac would not degrade the spectrum to where it would be detrimental to the radiated RF.

  3. Power factor control system for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1981-01-01

    A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.

  4. Improved transistorized AC motor controller for battery powered urban electric passenger vehicles

    NASA Technical Reports Server (NTRS)

    Peak, S. C.

    1982-01-01

    An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The power inverter is a three-phase bridge using power Darlington transistors. The induction motor was optimized for use with an inverter power source. The drive system has a constant torque output to base motor speed and a constant horsepower output to maximum speed. A gear shifting transmission is not required. The ac controller was scaled from the base 20 hp (41 hp peak) at 108 volts dec to an expanded horsepower and battery voltage range. Motor reversal was accomplished by electronic reversal of the inverter phase sequence. The ac controller can also be used as a boost chopper battery charger. The drive system was tested on a dynamometer and results are presented. The current-controlled pulse width modulation control scheme yielded improved motor current waveforms. The ac controller favors a higher system voltage.

  5. Development of software to improve AC power quality on large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, alternating current (AC) power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can become a serious problem. It can cause malfunctions in equipment that the power system is supplying, and, during distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. To address the harmonic distortion issue, work was begun under the 1990 NASA-ASEE Summer Faculty Fellowship Program. Software, originally developed by EPRI, called HARMFLO, a power flow program capable of analyzing harmonic conditions on three phase, balanced, 60 Hz AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The modelling was also started under the same fellowship work period. Details of the modifications and models completed during the 1990 NASA-ASEE Summer Faculty Fellowship Program can be found in a project report. As a continuation of the work to develop a complete package necessary for the full analysis of spacecraft AC power system behavior, deployment work has continued through NASA Grant NAG3-1254. This report details the work covered by the above mentioned grant.

  6. 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.

  7. Towards Effective Clustering Techniques for the Analysis of Electric Power Grids

    SciTech Connect

    Hogan, Emilie A.; Cotilla Sanchez, Jose E.; Halappanavar, Mahantesh; Wang, Shaobu; Mackey, Patrick S.; Hines, Paul; Huang, Zhenyu

    2013-11-30

    Clustering is an important data analysis technique with numerous applications in the analysis of electric power grids. Standard clustering techniques are oblivious to the rich structural and dynamic information available for power grids. Therefore, by exploiting the inherent topological and electrical structure in the power grid data, we propose new methods for clustering with applications to model reduction, locational marginal pricing, phasor measurement unit (PMU or synchrophasor) placement, and power system protection. We focus our attention on model reduction for analysis based on time-series information from synchrophasor measurement devices, and spectral techniques for clustering. By comparing different clustering techniques on two instances of realistic power grids we show that the solutions are related and therefore one could leverage that relationship for a computational advantage. Thus, by contrasting different clustering techniques we make a case for exploiting structure inherent in the data with implications for several domains including power systems.

  8. Designing a Distributed Systems Architecture Testbed for Real-Time Power Grid Systems

    SciTech Connect

    Liu, Yan; Gorton, Ian; Chen, Yousu; Jin, Shuangshuang

    2011-07-09

    Power engineers who are striving to improve real-time attribute of power grid applications are ill equipped with software engineering methods and tools that allow them to rigorously evaluate their designs, taken into account data communication, geographic locations, and high performance computing capacity. This paper presents a technical approach to designing a testbed for embedding real-time monitoring and computation functionalities into the power grid system. The approach focuses on integrating the parallel computational models with the data management infrastructure for near-real time power grid state estimation. We study and summarize various forces and requirements that drive the design decisions in the distributed systems architecture. Given the continental scale of the power grid, it is important for the testbed to be extensible and scalable within a complex topology of physical entities, controlled by an overlaid network of power utilities and regulatory balancing authorities. This paper outlines the technical steps, and software toolkits to develop this testbed.

  9. Motor power control circuit for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.

  10. 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.

  11. Wind power stabilization to achieve proper grid connection using power convertor & DSP Controller

    NASA Astrophysics Data System (ADS)

    Shejal, B. D.; Jamge, S. B.

    2010-11-01

    The wind power sources are characterized by irregularity, instability and unpredictability. In normal operation, random properties of wind and blade rotational turbulence can produce unwanted fluctuation on the voltage and power supplied into the system. Power output of a wind turbine is a function of wind speed. Wind turbine is a source of power fluctuations due to the nature of wind speed. This fluctuating power will have its impact on power balance and voltage at the point of common coupling. Small variation of wind speed could cause a large variation in the extracted power. As a result, large voltage fluctuation may result in voltage variations outside the regulation limit at connection point. In this paper, a method has been developed to reduce output power fluctuations of a wind turbine with an energy storage system using stator side converter. The developed method has been tested through modeling a doubly fed wind turbine and a battery storage system, using SimPower Systems tools of MATLAB and simulated for operation as a grid connected system.

  12. 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.

  13. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-09-05

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  14. A system for tranmitting low frequency analog signals over ac power lines

    DOEpatents

    Baker, S.P.; Durall, R.L.; Haynes, H.D.

    1987-07-30

    A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

  15. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-01-01

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  16. 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

  17. Non-oxidized porous silicon-based power AC switch peripheries

    NASA Astrophysics Data System (ADS)

    Menard, Samuel; Fèvre, Angélique; Valente, Damien; Billoué, Jérôme; Gautier, Gaël

    2012-10-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries.

  18. Non-oxidized porous silicon-based power AC switch peripheries.

    PubMed

    Menard, Samuel; Fèvre, Angélique; Valente, Damien; Billoué, Jérôme; Gautier, Gaël

    2012-01-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries. PMID:23057856

  19. Non-oxidized porous silicon-based power AC switch peripheries

    PubMed Central

    2012-01-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries. PMID:23057856

  20. The AC photovoltaic module is here!

    NASA Astrophysics Data System (ADS)

    Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

    1997-02-01

    This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

  1. Coupling an induction motor type generator to ac power lines. [making windmill generators compatible with public power lines

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1984-01-01

    A system for coupling an induction motor type generator to an A.C. power line includes an electronic switch means that is controlled by a control system and is regulated to turn on at a relatively late point in each half cycle of its operation. The energizing power supplied by the line to the induction motor type generator is decreased and the net power delivered to the line is increased.

  2. A Multi-Level Grid Interactive Bi-directional AC/DC-DC/AC Converter and a Hybrid Battery/Ultra-capacitor Energy Storage System with Integrated Magnetics for Plug-in Hybrid Electric Vehicles

    SciTech Connect

    Onar, Omer C

    2011-01-01

    This study presents a bi-directional multi-level power electronic interface for the grid interactions of plug-in hybrid electric vehicles (PHEVs) as well as a novel bi-directional power electronic converter for the combined operation of battery/ultracapacitor hybrid energy storage systems (ESS). The grid interface converter enables beneficial vehicle-to-grid (V2G) interactions in a high power quality and grid friendly manner; i.e, the grid interface converter ensures that all power delivered to/from grid has unity power factor and almost zero current harmonics. The power electronic converter that provides the combined operation of battery/ultra-capacitor system reduces the size and cost of the conventional ESS hybridization topologies while reducing the stress on the battery, prolonging the battery lifetime, and increasing the overall vehicle performance and efficiency. The combination of hybrid ESS is provided through an integrated magnetic structure that reduces the size and cost of the inductors of the ESS converters. Simulation and experimental results are included as prove of the concept presenting the different operation modes of the proposed converters.

  3. Development of a uninterrupted power system: ac and dc to dc converter

    NASA Technical Reports Server (NTRS)

    Cronin, D. L.; Schoenfeld, A. D.

    1973-01-01

    This program covered the design, fabrication and testing of an advanced development model uninterrupted power system. The input and output requirements imposed on the power processor were specified such that the unit is electrically interchangeable with existing power systems used by the Federal Aviation Administration in installations which have a history of failure due to electrical transient conditions. Input power is from either of two single-phase ac power sources or batteries with electronic selection and transfer between power sources. Battery reconditioning is automatic when either ac source is present. The output power is rated at 84OW; the nominal output is 24V at 35A. Within the 84OW limit, the regulated output voltage is adjustable from 22V to 30Vdc. Protection against continuous overloading or short circuit is provided. The unit is packaged in a standard 19-inch rack mount configuration with 7-inch panel height. Controls are on the front panel with power input and output through connectors on the rear surface. Cooling is by free convection from fin areas located on the side and rear panels. The packaged unit weighs 52.8 lbs., which can be reduced significantly if a three-phase ac power source is used.

  4. Improved transistorized ac motor controller for battery powered urban electric passenger vehicles

    SciTech Connect

    Peak, S.C.

    1982-09-01

    The objectives of this program for an improved ac motor controller for battery powered urban electric passenger vehicles were: the design, fabrication, test, evaluation and cost analysis of an engineering model controller for an ac induction motor drive system, the investigation of a power level expansion to a family of horsepower and battery system voltages, and the investigation of the applicability of the ac controller for use as an on-board battery charger and for providing the function of motor reversal. Additional vehicle specifications, e.g., acceleration and pulling out of potholes, were added to the NASA vehicle specifications. Then, a vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The General Electric ac induction motor used in the drive is optimized to operate as a vehicle traction motor with a pulse width modulated (PWM) inverter as a power source. The motor is nominally rated 20 hp and 41 hp peak. The power inverter design is a three-phase transistorized bridge configuration with feedback diodes. The transistors are a special design General Electric high-power Darlington transistor rated 450 volts and 200 amps. The battery system voltage chosen was 108 volts. The control strategy is a constant torque profile by PWM operation to base speed and a constant horsepower profile by square-wave operation to maximum speed. A gear shifting transmission is not required. An advanced current-controlled PWM technique is used to control the motor voltage. The primary feedback control is a motor angle control, with voltage and torque outer loop controls.

  5. Quantifiably secure power grid operation, management, and evolution : a study of uncertainties affecting the grid integration of renewables.

    SciTech Connect

    Gray, Genetha Anne; Watson, Jean-Paul; Silva Monroy, Cesar Augusto; Gramacy, Robert B.

    2013-09-01

    This report summarizes findings and results of the Quantifiably Secure Power Grid Operation, Management, and Evolution LDRD. The focus of the LDRD was to develop decisionsupport technologies to enable rational and quantifiable risk management for two key grid operational timescales: scheduling (day-ahead) and planning (month-to-year-ahead). Risk or resiliency metrics are foundational in this effort. The 2003 Northeast Blackout investigative report stressed the criticality of enforceable metrics for system resiliency - the grid's ability to satisfy demands subject to perturbation. However, we neither have well-defined risk metrics for addressing the pervasive uncertainties in a renewable energy era, nor decision-support tools for their enforcement, which severely impacts efforts to rationally improve grid security. For day-ahead unit commitment, decision-support tools must account for topological security constraints, loss-of-load (economic) costs, and supply and demand variability - especially given high renewables penetration. For long-term planning, transmission and generation expansion must ensure realized demand is satisfied for various projected technological, climate, and growth scenarios. The decision-support tools investigated in this project paid particular attention to tailoriented risk metrics for explicitly addressing high-consequence events. Historically, decisionsupport tools for the grid consider expected cost minimization, largely ignoring risk and instead penalizing loss-of-load through artificial parameters. The technical focus of this work was the development of scalable solvers for enforcing risk metrics. Advanced stochastic programming solvers were developed to address generation and transmission expansion and unit commitment, minimizing cost subject to pre-specified risk thresholds. Particular attention was paid to renewables where security critically depends on production and demand prediction accuracy. To address this concern, powerful

  6. Development of software to improve AC power quality on large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, AC power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can cause malfunctions in equipment that the power system is supplying, and during extreme distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. HARMFLO, a power flow computer program, which was capable of analyzing harmonic conditions on three phase, balanced, 60 Hz, AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The results are that (1) the harmonic power now has a model of a single phase, voltage controlled, full wave rectifier; and (2) HARMFLO was ported to the SUN workstation platform.

  7. NREL + SolarCity: Maximizing Solar Power on Electrical Grids

    SciTech Connect

    Hannegan, Bryan; Hanley, Ryan; Symko-Davies, Martha

    2015-06-03

    Learn how NREL is partnering with SolarCity to study how to better integrate rooftop solar onto the grid. The work includes collaboration with the Hawaiian Electric Companies (HECO) to analyze high-penetration solar scenarios using advanced modeling and inverter testing at the Energy Systems Integration Facility (ESIF) on NREL’s campus. Results to date have been so promising that HECO has more than doubled the amount of rooftop solar it allows on its grid, showing utilities across the country that distributed solar is not a liability for reliability—and can even be an asset.

  8. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered adjustable hospital bed. 880.5100 Section 880.5100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5100...

  9. 33. A.C. PANEL FOR MENTONE POWER HOUSE, P.L. & P. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. A.C. PANEL FOR MENTONE POWER HOUSE, P.L. & P. CO., LOS ANGELES. RETRACED FROM MASSON'S DRAWING NO. C-275. JAN. 20, 1909. SCE drawing no. 52880. - Santa Ana River Hydroelectric System, SAR-3 Powerhouse, San Bernardino National Forest, Redlands, San Bernardino County, CA

  10. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices § 880.6320...

  11. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal...

  12. Efficient Switches for Solar Power Conversion: Four Quadrant GaN Switch Enabled Three Phase Grid-Tied Microinverters

    SciTech Connect

    2012-02-13

    Solar ADEPT Project: Transphorm is developing power switches for new types of inverters that improve the efficiency and reliability of converting energy from solar panels into useable electricity for the grid. Transistors act as fast switches and control the electrical energy that flows in an electrical circuit. Turning a transistor off opens the circuit and stops the flow of electrical current; turning it on closes the circuit and allows electrical current to flow. In this way a transistor can be used to convert DC from a solar panel into AC for use in a home. Transphorm’s transistors will enable a single semiconductor device to switch electrical currents at high-voltage in both directions—making the inverter more compact and reliable. Transphorm is using Gallium Nitride (GaN) as a semiconductor material in its transistors instead of silicon, which is used in most conventional transistors, because GaN transistors have lower losses at higher voltages and switching frequencies.

  13. Vehicle-to-grid power implementation: From stabilizing the grid to supporting large-scale renewable energy

    NASA Astrophysics Data System (ADS)

    Kempton, Willett; Tomić, Jasna

    Vehicle-to-grid power (V2G) uses electric-drive vehicles (battery, fuel cell, or hybrid) to provide power for specific electric markets. This article examines the systems and processes needed to tap energy in vehicles and implement V2G. It quantitatively compares today's light vehicle fleet with the electric power system. The vehicle fleet has 20 times the power capacity, less than one-tenth the utilization, and one-tenth the capital cost per prime mover kW. Conversely, utility generators have 10-50 times longer operating life and lower operating costs per kWh. To tap V2G is to synergistically use these complementary strengths and to reconcile the complementary needs of the driver and grid manager. This article suggests strategies and business models for doing so, and the steps necessary for the implementation of V2G. After the initial high-value, V2G markets saturate and production costs drop, V2G can provide storage for renewable energy generation. Our calculations suggest that V2G could stabilize large-scale (one-half of US electricity) wind power with 3% of the fleet dedicated to regulation for wind, plus 8-38% of the fleet providing operating reserves or storage for wind. Jurisdictions more likely to take the lead in adopting V2G are identified.

  14. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... powered device either fixed or mobile, used to lift and transport patients in the horizontal or other required position from one place to another, as from a bed to a bath. The device includes straps and slings to support the patient. (b) Classification. Class II (special controls). The device is exempt...

  15. Feasibility of Hybrid Retrofits to Off-Grid Diesel Power Plants in the Philippines

    SciTech Connect

    Barley, C. D.; Flowers, L. T.; Benavidez, P. J.; Abergas, R. L.; Barruela, R. B.

    1999-08-01

    The Strategic Power Utilities Group (SPUG) of the National Power Corporation (NPC) in the Philippines owns and operates about 100 power plants, mostly fueled by diesel, ranging in energy production from about 15 kilowatt-hours (kWh)/day to 106,000 kWh/day. Reducing the consumption of diesel fuel in these plants, along with the associated financial losses, is a priority for SPUG. The purpose of this study is to estimate the potential fuel and cost savings that might be achieved by retrofitting hybrid power systems to these existing diesel plants. As used in this report, the term ''hybrid system'' refers to any combination of wind turbine generators (WTGs), photovoltaic (PV) modules, lead-acid batteries, and an AC/DC power converter (either an electronic inverter or a rotary converter), in addition to the existing diesel gensets. The resources available for this study did not permit a detailed design analysis for each of the plants. Instead, the following five-step process was used: (1) Tabulate some important characteristics of all the plants. (2) Group the plants into categories (six classes) with similar characteristics. (3) For each class of system, identify one plant that is representative of the class. (4) For each representative plant, perform a moderately detailed prefeasibility analysis of design options. (5) Summarize and interpret the results. The analysis of each representative plant involved the use of time-series computer simulation models to estimate the fuel usage, maintenance expenses, and cash flow resulting from various designs, and to search the domain of possible designs for the one leading to the lowest life-cycle cost. Cost items that would be unaffected by the retrofit, such as operator salaries and the capital cost of existing equipment, were not included in the analysis. Thus, the results are reported as levelized cost of energy (COE) savings: the difference between the cost of the existing diesel-only system and that of an optimized hybrid

  16. Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System

    NASA Astrophysics Data System (ADS)

    Bhende, C. N.; Kalam, A.; Malla, S. G.

    2016-04-01

    Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.

  17. Grid Interconnection and Performance Testing Procedures for Vehicle-To-Grid (V2G) Power Electronics: Preprint

    SciTech Connect

    Kramer, W.; Chakraborty, S.; Kroposki, B.; Hoke, A.; Martin, G.; Markel, T.

    2012-03-01

    Bidirectional power electronics can add vehicle-to-grid (V2G) capability in a plug-in vehicle, which then allows the vehicle to operate as a distributed resource (DR). The uniqueness of the battery-based V2G power electronics requires a test procedure that will not only maintain IEEE interconnection standards, but can also evaluate the electrical performance of the vehicle working as a DR. The objective of this paper is to discuss a recently published NREL technical report that provides interim test procedures for V2G vehicles for their integration into the electrical distribution systems and for their performance in terms of continuous output power, efficiency, and losses. Additionally, some other test procedures are discussed that are applicable to a V2G vehicle that desires to provide power reserve functions. A few sample test results are provided based on testing of prototype V2G vehicles at NREL.

  18. Development of a 10 kW High Temperature High Power Density Three-Phase AC-DC-AC SiC Converter

    SciTech Connect

    Ning, Puqi

    2012-01-01

    This paper presents the development and experimental performance of a 10 kW, all SiC, 250 C junction temperature high-power-density three-phase ac-dc-ac converter. The electromagnetic interference filter, thermal system, high temperature package, and gate drive design are discussed in detail. Finally, tests confirming the feasibility and validating the theoretical basis of the prototype converter system are described.

  19. Research and Development of Region Power Grid Wind Hazard Precaution System

    NASA Astrophysics Data System (ADS)

    Jun, Xiong; Han, Lin; Qinghua, Wang; Junjia, He

    The severe wind is one of the most threatening natural disasters for power grid operation. To solve the problem of the wind hazard assessment of power grid, a region power grid wind hazard precaution system is proposed in this paper by using weather and power grid data and geographical information. This system consists of two forecast models that the first is the statistical diagnosis model based on Partial least-squares and Model Output Statistics (PLS-MOS) method, and the second is the numerical forecasting model by the combination of mesoscale numerical model and microscale boundary layer model (MM5-CALMAT). Finally, according to the wind-resistant design parameters of transmission towers, a precaution information management platform based on the grid disaster prevention and reduction system (GDPRS) is supplied in order to remind the relevant operator for their decision-making and emergency treatment through real-time SMS and GIS location display. It is of important practical significance and application value for power grid disaster prevention and reduction.

  20. Risk-based generation dispatch in the power grid for resilience against extreme weather events

    NASA Astrophysics Data System (ADS)

    Javanbakht, Pirooz

    Natural disasters have been considered as one of the main causes of the largest blackouts in North America. When it comes to power grid resiliency against natural hazards, different solutions exist that are mainly categorized based on the time-frame of analysis. At the design stage, robustness and resiliency may be improved through redundant designs and inclusion of advanced measurement, monitoring, control and protection systems. However, since massive destructive energy may be released during the course of a natural disaster (such as a hurricane) causing large-scale and widespread disturbances, design-stage remedies may not be sufficient for ensuring power grid robustness. As a result, to limit the consequent impacts on the operation of the power grid, the system operator may be forced to take immediate remedial actions in real-time. To effectively manage the disturbances caused by severe weather events, weather forecast information should be incorporated into the operational model of the power grid in order to predict imminent contingencies. In this work, a weather-driven generation dispatch model is developed based on stochastic programming to provide a proactive solution for power grid resiliency against imminent large-scale disturbances. Hurricanes and ice storms are studied as example disaster events to provide numerical results. In this approach, the statistics of the natural disaster event are taken into account along with the expected impact on various power grid components in order to determine the availability of the grid. Then, a generation dispatch strategy is devised that helps operate the grid subject to weather-driven operational constraints.

  1. Static state estimation of multiterminal DC/AC power system in rectangular co-ordinates

    SciTech Connect

    Roy, L.; Sinha, A.K. ); Srivastava, H.N.P. )

    1991-01-01

    This paper describes a simple, efficient and reliable method for estimating the state of an integrated multiterminal HVDC/AC power system in the rectangular coordinate form. A six variable model is used to represent the converter system. The proposed algorithm performs successfully in obtaining the state of an AC system with a DC link or a multiterminal DC network. It is possible to implement it for an on-line state estimation. Simulation results of a 30-busbar system are presented for illustration.

  2. Comprehensive review of high power factor ac-dc boost converters for PFC applications

    NASA Astrophysics Data System (ADS)

    De Castro Pereira, Dênis; Da Silva, Márcio Renato; Mateus Silva, Elder; Lessa Tofoli, Fernando

    2015-08-01

    High power factor rectifiers have been consolidated as an effective solution to improve power quality indices in terms of input power factor correction, reduction in the total harmonic distortion of the input current and also regulated dc voltages. Within this context, this subject has motivated the introduction of numerous converter topologies based on classic dc-dc structures associated with novel control techniques, thus leading to the manufacturing of dedicated integrated circuits that allow high input power factor by adding a front-end stage to switch-mode converters. In particular, boost converters in continuous current mode (CCM) are widely employed since they allow obtaining minimised electromagnetic interference levels. This work is concerned with a literature review involving relevant ac-dc single-phase boost-based topologies with high input power factor. The evolution of aspects regarding the conventional boost converter is shown in terms of improved characteristics inherent to other ac-dc boost converters. Additionally, the work intends to be a fast and concise reference to single-phase ac-dc boost converters operating in CCM for engineers, researchers and experts in the field of power electronics by properly analysing and comparing the aforementioned rectifiers.

  3. 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.

  4. A novel wireless power and data transmission AC to DC converter for an implantable device.

    PubMed

    Liu, Jhao-Yan; Tang, Kea-Tiong

    2013-01-01

    This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz. PMID:24110077

  5. Multi-Fluid Geothermal Energy Systems: Using CO2 for Dispatchable Renewable Power Generation and Grid Stabilization

    NASA Astrophysics Data System (ADS)

    Buscheck, T. A.; Bielicki, J. M.; Randolph, J.; Chen, M.; Hao, Y.; Sun, Y.

    2013-12-01

    pumps, the thermosiphon directly converts reservoir thermal energy into mechanical energy for fluid circulation. Because stored pressure drives fluid production, the response time is faster than that of conventional geothermal power, already considered to be dispatchable. For conventional geothermal, the parasitic power load is in phase with gross power output. In contrast, our approach can time-shift much of the parasitic power load, which is dominated by the power required to separate N2 from air and compress it for injection. Because N2 is readily available, it can be injected intermittently. Thus, most of the parasitic power load can be shifted to coincide with minimum power demand or when there is a surplus of renewable power. Such a time-shift also allows net power output to be nearly equal to gross power output during peak demand. Energy storage can be almost 100 percent efficient because it is achieved by shifting the parasitic load, which is more efficient than other methods used to store energy and stabilize the grid. This work was performed under the auspices of the U.S. DOE by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  6. A study of some features of ac and dc electric power systems for a space station

    NASA Technical Reports Server (NTRS)

    Hanania, J. I.

    1983-01-01

    This study analyzes certain selected topics in rival dc and high frequency ac electric power systems for a Space Station. The interaction between the Space Station and the plasma environment is analyzed, leading to a limit on the voltage for the solar array and a potential problem with resonance coupling at high frequencies. Certain problems are pointed out in the concept of a rotary transformer, and further development work is indicated in connection with dc circuit switching, special design of a transmission conductor for the ac system, and electric motors. The question of electric shock hazards, particularly at high frequency, is also explored. and a problem with reduced skin resistance and therefore increased hazard with high frequency ac is pointed out. The study concludes with a comparison of the main advantages and disadvantages of the two rival systems, and it is suggested that the choice between the two should be made after further studies and development work are completed.

  7. Electromechanical systems with transient high power response operating from a resonant ac link

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Hansen, Irving G.

    1992-01-01

    The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant ac link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control all four operating quadrants. Incorporating the ac link allows the converter in these systems to switch at the zero crossing of every half cycle of the ac waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed under contract to NASA.

  8. AC loss in high-temperature superconducting conductors, cables and windings for power devices

    NASA Astrophysics Data System (ADS)

    Oomen, M. P.; Rieger, J.; Hussennether, V.; Leghissa, M.

    2004-05-01

    High-temperature superconducting (HTS) transformers and reactor coils promise decreased weight and volume and higher efficiency. A critical design parameter for such devices is the AC loss in the conductor. The state of the art for AC-loss reduction in HTS power devices is described, starting from the loss in the single HTS tape. Improved tape manufacturing techniques have led to a significant decrease in the magnetization loss. Transport-current loss is decreased by choosing the right operating current and temperature. The role of tape dimensions, filament twist and resistive matrix is discussed and a comparison is made between state-of-the-art BSCCO and YBCO tapes. In transformer and reactor coils the AC loss in the tape is influenced by adjacent tapes in the coil, fields from other coils, overcurrents and higher harmonics. These factors are accounted for by a new AC-loss prediction model. Field components perpendicular to the tape are minimized by optimizing the coil design and by flux guidance pieces. High-current windings are made of Roebel conductors with transposed tapes. The model iteratively finds the temperature distribution in the winding and predicts the onset of thermal instability. We have fabricated and tested several AC windings and used them to validate the model. Now we can confidently use the model as an engineering tool for designing HTS windings and for determining the necessary tape properties.

  9. Grid regulation services for energy storage devices based on grid frequency

    SciTech Connect

    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).

  10. Grid regulation services for energy storage devices based on grid frequency

    SciTech Connect

    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).

  11. 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

  12. Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications

    NASA Astrophysics Data System (ADS)

    Cao, Dong

    Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non

  13. Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

    SciTech Connect

    Albuquerque, Fabio L.; Moraes, Adelio J.; Guimaraes, Geraldo C.; Sanhueza, Sergio M.R.; Vaz, Alexandre R.

    2010-07-15

    In the case of photovoltaic (PV) systems acting as distributed generation (DG) systems, the DC energy that is produced is fed to the grid through the power-conditioning unit (inverter). The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can replace CSIs, we can generate reactive power proportionally to the remaining unused capacity at any given time. According to the theory of instantaneous power, the inverter reactive power can be regulated by changing the amplitude of its output voltage. In addition, the inverter active power can be adjusted by modifying the phase angle of its output voltage. Based on such theory, both the active power supply and the reactive power compensation (RPC) can be carried out simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of a PV system can still be used to improve the inverter utilisation factor. Some MATLAB simulation results are included here to show the feasibility of the method. (author)

  14. NREL Confirms Large Potential for Grid Integration of Wind, Solar Power (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from these renewable resources could be integrated reliably into the grid. To inform the discussion about the potential of such variable sources, the National Renewable Energy Laboratory (NREL) launched two key regional studies, examining the east and west sections of the U.S. power grid. The studies show that it is technically possible for U.S. power systems to integrate 20%-35% renewable electricity if infrastructure and operational improvements can be made.

  15. Method and system for managing power grid data

    SciTech Connect

    Yin, Jian; Akyol, Bora A.; Gorton, Ian

    2015-11-10

    A system and method of managing time-series data for smart grids is disclosed. Data is collected from a plurality of sensors. An index is modified for a newly created block. A one disk operation per read or write is performed. The one disk operation per read includes accessing and looking up the index to locate the data without movement of an arm of the disk, and obtaining the data. The one disk operation per write includes searching the disk for free space, calculating an offset, modifying the index, and writing the data contiguously into a block of the disk the index points to.

  16. Computer-aided optimization of grid design for high-power lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Yamada, Keizo; Maeda, Ken-ichi; Sasaki, Kazuya; Hirasawa, Tokiyoshi

    Several high-power lead-acid batteries have been developed for automotive applications. A computer-aided optimization (CAO) technique has been used to obtain a low-resistance grid design. Unlike conventional computer simulation, the CAO technique does not require an unduly large number of designs to yield a good result. After introducing a pair of differential equations that are expected to be valid for the optimized design, the grid thickness is optimized by solving the boundary value problem of coupled differential equations. When applied for the grids of JIS B-size batteries, this technique reduces the potential drop of electrical resistance in a electrode by 11-14%.

  17. Uncertainty Analysis of Power Grid Investment Capacity Based on Monte Carlo

    NASA Astrophysics Data System (ADS)

    Qin, Junsong; Liu, Bingyi; Niu, Dongxiao

    By analyzing the influence factors of the investment capacity of power grid, to depreciation cost, sales price and sales quantity, net profit, financing and GDP of the second industry as the dependent variable to build the investment capacity analysis model. After carrying out Kolmogorov-Smirnov test, get the probability distribution of each influence factor. Finally, obtained the grid investment capacity uncertainty of analysis results by Monte Carlo simulation.

  18. Improved SCR ac Motor Controller for Battery Powered Urban Electric Vehicles

    NASA Technical Reports Server (NTRS)

    Latos, T. S.

    1982-01-01

    An improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery would provide a complete electric vehicle power train with the exception of the mechanical transmission and drive wheels was designed. In such a system, the motor controller converts the dc electrical power available at the battery terminals to ac electrical power for the induction motor in response to the drivers commands. The performance requirements of a hypothetical electric vehicle with an upper weight bound of 1590 kg (3500 lb) were used to determine the power rating of the controller. Vehicle acceleration capability, top speed, and gradeability requisites were contained in the Society of Automotive Engineers (SAE) Schedule 227a(d) driving cycle. The important capabilities contained in this driving cycle are a vehicle acceleration requirement of 0 to 72.4 kmph (0 to 45 mph) in 28 seconds a top speed of 88.5 kmph (55 mph), and the ability to negotiate a 10% grade at 48 kmph (30 mph). A 10% grade is defined as one foot of vertical rise per 10 feet of horizontal distance.

  19. Synchronization Algorithms for Co-Simulation of Power Grid and Communication Networks

    SciTech Connect

    Ciraci, Selim; Daily, Jeffrey A.; Agarwal, Khushbu; Fuller, Jason C.; Marinovici, Laurentiu D.; Fisher, Andrew R.

    2014-09-11

    The ongoing modernization of power grids consists of integrating them with communication networks in order to achieve robust and resilient control of grid operations. To understand the operation of the new smart grid, one approach is to use simulation software. Unfortunately, current power grid simulators at best utilize inadequate approximations to simulate communication networks, if at all. Cooperative simulation of specialized power grid and communication network simulators promises to more accurately reproduce the interactions of real smart grid deployments. However, co-simulation is a challenging problem. A co-simulation must manage the exchange of informa- tion, including the synchronization of simulator clocks, between all simulators while maintaining adequate computational perfor- mance. This paper describes two new conservative algorithms for reducing the overhead of time synchronization, namely Active Set Conservative and Reactive Conservative. We provide a detailed analysis of their performance characteristics with respect to the current state of the art including both conservative and optimistic synchronization algorithms. In addition, we provide guidelines for selecting the appropriate synchronization algorithm based on the requirements of the co-simulation. The newly proposed algorithms are shown to achieve as much as 14% and 63% im- provement, respectively, over the existing conservative algorithm.

  20. Comparative Study of Standards for Grid-Connected Wind Power Plant in China and the U.S.

    SciTech Connect

    Gao, Wenzhong; Tian, Tian; Muljadi, Eduard; Zhang, Yincheng; Miller, Mackay; Wang, Weisheng; Wang, Jing

    2015-10-06

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

  1. Realistic modeling and analysis of synchronization dynamics in power-grid networks

    NASA Astrophysics Data System (ADS)

    Nishikawa, Takashi

    2015-03-01

    An imperative condition for the functioning of a power-grid network is that its power generators remain synchronized. Disturbances can prompt desynchronization, which is a process that has been involved in large power outages. In this talk I will first give a comparative review of three leading models of synchronization in power-grid networks. Each of these models can be derived from first principles under a common framework and represents a power grid as a complex network of coupled second-order phase oscillators with both forcing and damping terms. Since these models require dynamical parameters that are unavailable in typical power-grid datasets, I will discuss an approach to estimate these parameters. The models will be used to show that if the network structure is not homogeneous, generators with identical parameters need to be treated as non-identical oscillators in general. For one of the models, which describes the dynamics of coupled generators through a network of effective interactions, I will derive a condition under which the desired synchronous state is stable. This condition gives rise to a methodology to specify parameter assignments that can enhance synchronization of any given network, which I will demonstrate for a selection of both test systems and real power grids. These parameter assignments can be realized through very fast control loops, and this may help devise new control schemes that offer an additional layer of protection, thus contributing to the development of smart grids that can recover from failures in real time. Funded by ISEN, NSF, and LANL LDRD.

  2. Co-Simulation of Detailed Whole Building with the Power System to Study Smart Grid Applications

    SciTech Connect

    Makhmalbaf, Atefe; Fuller, Jason C.; Srivastava, Viraj; Ciraci, Selim; Daily, Jeffrey A.

    2014-12-24

    Modernization of the power system in a way that ensures a sustainable energy system is arguably one of the most pressing concerns of our time. Buildings are important components in the power system. First, they are the main consumers of electricity and secondly, they do not have constant energy demand. Conventionally, electricity has been difficult to store and should be consumed as it is generated. Therefore, maintaining the demand and supply is critical in the power system. However, to reduce the complexity of power models, buildings (i.e., end-use loads) are traditionally modeled and represented as aggregated “dumb” nodes in the power system. This means we lack effective detailed whole building energy models that can support requirements and emerging technologies of the smart power grid. To gain greater insight into the relationship between building energy demand and power system performance, it is important to constitute a co-simulation framework to support detailed building energy modeling and simulation within the power system to study capabilities promised by the modern power grid. This paper discusses ongoing work at Pacific Northwest National Laboratory and presents underlying tools and framework needed to enable co-simulation of building, building energy systems and their control in the power system to study applications such as demand response, grid-based HVAC control, and deployment of buildings for ancillary services. The optimal goal is to develop an integrated modeling and simulation platform that is flexible, reusable, and scalable. Results of this work will contribute to future building and power system studies, especially those related to the integrated ‘smart grid’. Results are also expected to advance power resiliency and local (micro) scale grid studies where several building and renewable energy systems transact energy directly. This paper also reviews some applications that can be supported and studied using the framework introduced

  3. Developing Information Power Grid Based Algorithms and Software

    NASA Technical Reports Server (NTRS)

    Dongarra, Jack

    1998-01-01

    This was an exploratory study to enhance our understanding of problems involved in developing large scale applications in a heterogeneous distributed environment. It is likely that the large scale applications of the future will be built by coupling specialized computational modules together. For example, efforts now exist to couple ocean and atmospheric prediction codes to simulate a more complete climate system. These two applications differ in many respects. They have different grids, the data is in different unit systems and the algorithms for inte,-rating in time are different. In addition the code for each application is likely to have been developed on different architectures and tend to have poor performance when run on an architecture for which the code was not designed, if it runs at all. Architectural differences may also induce differences in data representation which effect precision and convergence criteria as well as data transfer issues. In order to couple such dissimilar codes some form of translation must be present. This translation should be able to handle interpolation from one grid to another as well as construction of the correct data field in the correct units from available data. Even if a code is to be developed from scratch, a modular approach will likely be followed in that standard scientific packages will be used to do the more mundane tasks such as linear algebra or Fourier transform operations. This approach allows the developers to concentrate on their science rather than becoming experts in linear algebra or signal processing. Problems associated with this development approach include difficulties associated with data extraction and translation from one module to another, module performance on different nodal architectures, and others. In addition to these data and software issues there exists operational issues such as platform stability and resource management.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  5. An operational power management method for the grid containing renewable power systems utilizing short-term weather and load forecasting data

    NASA Astrophysics Data System (ADS)

    Aula, Fadhil T.; Lee, Samuel C.

    2013-04-01

    This paper addresses the problems associated with power management of the grid containing renewable power systems and proposes a method for enhancing its operational power management. Since renewable energy provides uncertain and uncontrollable energy resources, the renewable power systems can only generate irregular power. This power irregularity creates problems affecting the grid power management process and influencing the parallel operations of conventional power plants on the grid. To demonstrate this power management method for this type of grid, weatherdependent wind and photovoltaic power systems are chosen an example. This study also deals with other uncertain quantities which are system loads. In this example, the management method is based on adapting short-term weather and load forecasting data. The new load demand curve (NLDC) can be produced by merging the loads with the power generated from the renewable power systems. The NLDC is used for setting the loads for the baseload power plants and knowing when other plants are needed to increase or decrease their supplies to the grid. This will decrease the irregularity behavior effects of the renewable power system and at the same time will enhance the smoothing of the power management for the grid. The aim of this paper is to show the use of the weather and load forecasting data to achieve the optimum operational power management of the grid contains renewable power systems. An illustrative example of such a power system is presented and verified by simulation.

  6. Very low noise AC/DC power supply systems for large detector arrays

    NASA Astrophysics Data System (ADS)

    Arnaboldi, C.; Baù, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A.; Pessina, G.

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μVRMS (CUORE setup) and 90 μVRMS (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

  7. Very low noise AC/DC power supply systems for large detector arrays.

    PubMed

    Arnaboldi, C; Baù, A; Carniti, P; Cassina, L; Giachero, A; Gotti, C; Maino, M; Passerini, A; Pessina, G

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μV(RMS) (CUORE setup) and 90 μV(RMS) (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled). PMID:26724052

  8. Optimization Strategies for the Vulnerability Analysis of the Electric Power Grid

    SciTech Connect

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

    2007-11-13

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

  9. Optimization strategies for the vulnerability analysis of the electric power grid.

    SciTech Connect

    Meza, Juan C.; Pinar, Ali; Lesieutre, Bernard; Donde, Vaibhav

    2009-03-01

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

  10. Coupling Electric Vehicles and Power Grid through Charging-In-Motion and Connected Vehicle Technology

    SciTech Connect

    Li, Jan-Mou; Jones, Perry T; Onar, Omer C; Starke, Michael R

    2014-01-01

    A traffic-assignment-based framework is proposed to model the coupling of transportation network and power grid for analyzing impacts of energy demand from electric vehicles on the operation of power distribution. Although the reverse can be investigated with the proposed framework as well, electricity flowing from a power grid to electric vehicles is the focus of this paper. Major variables in transportation network (including link flows) and power grid (including electricity transmitted) are introduced for the coupling. Roles of charging-in-motion technology and connected vehicle technology have been identified in the framework of supernetwork. A linkage (i.e. individual energy demand) between the two networks is defined to construct the supernetwork. To determine equilibrium of the supernetwork can also answer how many drivers are going to use the charging-in-motion services, in which locations, and at what time frame. An optimal operation plan of power distribution will be decided along the determination simultaneously by which we have a picture about what level of power demand from the grid is expected in locations during an analyzed period. Caveat of the framework and possible applications have also been discussed.

  11. Electromechanical systems with transient high power response operating from a resonant AC link

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Hansen, Irving G.

    1992-01-01

    The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant AC link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control in all four operating quadrants. Incorporating the AC link allows the converter in these systems to switch at the zero crossing of every half cycle of the AC waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed by LeRC and General Dynamics Space Systems Division under contract to NASA. A description of a single motor, electromechanical actuation system is presented. Then, focus is on a conceptual design for an AC electric vehicle. This design incorporates an induction motor/generator together with a flywheel for peak energy storage. System operation and implications along with the associated circuitry are addressed. Such a system would greatly improve all-electric vehicle ranges over the Federal Urban Driving Cycle (FUD).

  12. Linear stability and the Braess paradox in coupled-oscillator networks and electric power grids

    NASA Astrophysics Data System (ADS)

    Coletta, Tommaso; Jacquod, Philippe

    2016-03-01

    We investigate the influence that adding a new coupling has on the linear stability of the synchronous state in coupled-oscillator networks. Using a simple model, we show that, depending on its location, the new coupling can lead to enhanced or reduced stability. We extend these results to electric power grids where a new line can lead to four different scenarios corresponding to enhanced or reduced grid stability as well as increased or decreased power flows. Our analysis shows that the Braess paradox may occur in any complex coupled system, where the synchronous state may be weakened and sometimes even destroyed by additional couplings.

  13. a Network of Oscillators Emulating the Italian High-Voltage Power Grid

    NASA Astrophysics Data System (ADS)

    Fortuna, Luigi; Frasca, Mattia; Sarra Fiore, Angelo

    2012-10-01

    In this paper, a dynamical model based on Kuramoto-like oscillators is used to represent the Italian high-voltage power grid. Nodes of the network are generators/substations, while links are the physical connections between generators/substations. The normal operating regime of the power grid corresponds to the regime in which the oscillations of all the nodes are synchronized. We studied the conditions for synchronization and the effect of dynamical perturbations on the nodes. The analysis allows to define several dynamical parameters assessing the dynamical robustness of the network.

  14. 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.

  15. Fuzzy based power factor improvement strategy for a multiple connected AC-DC converter fed drive

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, N.; Muthiah, Ramaswamy

    2012-01-01

    The main focus of this paper is to design a Fuzzy based control algorithm to realize an improvement in the input power factor of a multiple connected AC-DC converter fed drive system. It incorporates the role of fuzzy inference principles to generate appropriate PWM pulses for the power switches at the second stage of the power module. The philosophy is developed, with a view to reshape the input current phasor and enables it to align with the supply voltage wave in the perspective of improving the input power factor. The closed loop scheme evaluated using MATLAB based simulation exhibits an enhancement in supply power factor over a range of operating loads in addition to illustrating the speed regulating capability of the drive.

  16. ESBWR response to an extended station blackout/loss of all AC power

    SciTech Connect

    Barrett, A. J.; Marquino, W.

    2012-07-01

    U.S. federal regulations require light water cooled nuclear power plants to cope with Station Blackouts for a predetermined amount of time based on design factors for the plant. U.S. regulations define Station Blackout (SBO) as a loss of the offsite electric power system concurrent with turbine trip and unavailability of the onsite emergency AC power system. According to U.S. regulations, typically the coping period for an SBO is 4 hours and can be as long as 16 hours for currently operating BWR plants. Being able to cope with an SBO and loss of all AC power is required by international regulators as well. The U.S. licensing basis for the ESBWR is a coping period of 72 hours for an SBO based on U.S. NRC requirements for passive safety plants. In the event of an extended SBO (viz., greater than 72 hours), the ESBWR response shows that the design is able to cope with the event for at least 7 days without AC electrical power or operator action. ESBWR is a Generation III+ reactor design with an array of passive safety systems. The ESBWR primary success path for mitigation of an SBO event is the Isolation Condenser System (ICS). The ICS is a passive, closed loop, safety system that initiates automatically on a loss of power. Upon Station Blackout or loss of all AC power, the ICS begins removing decay heat from the Reactor Pressure Vessel (RPV) by (i) condensing the steam into water in heat exchangers located in pools of water above the containment, and (ii) transferring the decay heat to the atmosphere. The condensed water is then returned by gravity to cool the reactor again. The ICS alone is capable of maintaining the ESBWR in a safe shutdown condition after an SBO for an extended period. The fuel remains covered throughout the SBO event. The ICS is able to remove decay heat from the RPV for at least 7 days and maintains the reactor in a safe shutdown condition. The water level in the RPV remains well above the top of active fuel for the duration of the SBO event

  17. High power switch mode linear amplifiers for flexible ac transmission system

    SciTech Connect

    Mwinyiwiwa, B.; Wolanski, Z.; Ooi, B.T.

    1996-10-01

    The Pulse Width Modulation (PWM) technique has been proposed for the force-commutated Shunt and Series VAR Controllers and Unified Power Flow Controllers in Flexible AC Transmission Systems. The PWM converters can be operated as linear amplifiers of constant gain so that treasure trove of linear control system theory can be brought to bear more easily when applying feedback controls. For example, pole-placement and active filtering have been successfully applied in laboratory models. This paper is written as a tutorial describing the stages of signal processing: modulation, amplification and demodulation, without reference to power electronics since the solid-state switches are modelled as ON-OFF switches.

  18. A Testbed for Deploying Distributed State Estimation in Power Grid

    SciTech Connect

    Jin, Shuangshuang; Chen, Yousu; Rice, Mark J.; Liu, Yan; Gorton, Ian

    2012-07-22

    Abstract—With the increasing demand, scale and data information of power systems, fast distributed applications are becoming more important in power system operation and control. This paper proposes a testbed for evaluating power system distributed applications, considering data exchange among distributed areas. A high-performance computing (HPC) version of distributed state estimation is implemented and used as a distributed application example. The IEEE 118-bus system is used to deploy the parallel distributed state estimation, and the MeDICi middleware is used for data communication. The performance of the testbed demonstrates its capability to evaluate parallel distributed state estimation by leveraging the HPC paradigm. This testbed can also be applied to evaluate other distributed applications.

  19. Vehicle-to-grid power fundamentals: Calculating capacity and net revenue

    NASA Astrophysics Data System (ADS)

    Kempton, Willett; Tomić, Jasna

    As the light vehicle fleet moves to electric drive (hybrid, battery, and fuel cell vehicles), an opportunity opens for "vehicle-to-grid" (V2G) power. This article defines the three vehicle types that can produce V2G power, and the power markets they can sell into. V2G only makes sense if the vehicle and power market are matched. For example, V2G appears to be unsuitable for baseload power—the constant round-the-clock electricity supply—because baseload power can be provided more cheaply by large generators, as it is today. Rather, V2G's greatest near-term promise is for quick-response, high-value electric services. These quick-response electric services are purchased to balance constant fluctuations in load and to adapt to unexpected equipment failures; they account for 5-10% of electric cost—$ 12 billion per year in the US. This article develops equations to calculate the capacity for grid power from three types of electric drive vehicles. These equations are applied to evaluate revenue and costs for these vehicles to supply electricity to three electric markets (peak power, spinning reserves, and regulation). The results suggest that the engineering rationale and economic motivation for V2G power are compelling. The societal advantages of developing V2G include an additional revenue stream for cleaner vehicles, increased stability and reliability of the electric grid, lower electric system costs, and eventually, inexpensive storage and backup for renewable electricity.

  20. Real-time dynamic security assessment of power grids

    NASA Astrophysics Data System (ADS)

    Kerin, Uros; Heyde, Chris; Krebs, Rainer; Lerch, Edwin

    2014-09-01

    This paper presents a dynamic security assessment solution, which can be used in the power system control room to improve system stability. It is based on a set of security indices. The indices are able of establishing contingencies' severity levels as a measure of different aspects of power system security. A system based on fuzzy logic is used to combine the indices into a single composite index. The composite index is able to alert the control operator to the network conditions that represent a significant risk to system security based on over-all system performance.

  1. Real-time dynamic security assessment of power grids

    NASA Astrophysics Data System (ADS)

    Kerin, Uros; Heyde, Chris; Krebs, Rainer; Lerch, Edwin

    2014-10-01

    This paper presents a dynamic security assessment solution, which can be used in the power system control room to improve system stability. It is based on a set of security indices. The indices are able of establishing contingencies' severity levels as a measure of different aspects of power system security. A system based on fuzzy logic is used to combine the indices into a single composite index. The composite index is able to alert the control operator to the network conditions that represent a significant risk to system security based on over-all system performance.

  2. Renewable power production in a Pan-Caribbean energy grid

    NASA Astrophysics Data System (ADS)

    Miller, David

    The Small Island Developing States of the Caribbean are victims of geography and geopolitics. Lacking access to large fossil fuel reserves, they are forced to import fuel at prices they have no control over. Renewable energy resources, particularly wind, have the potential to help break the Caribbean dependency on fossil fuels and allow for increased development at the same time. Working from a sustainable development point of view, this project discusses the history of the area, the theoretical background for the idea of large scale renewable power production, the regional initiatives already in place that address both the cost of fossil fuels and the policy hurdles that need to be overcome to assist the region in gaining energy independence. Haiti is highlighted as a special case in the region and the potential use of several renewable resources are discussed, along with a potential business model based on the idea of the Internet. Power storage is covered, specifically the potential of battery operated vehicles to have a positive impact on the Caribbean region and other developing states. The role of government regulation and policy comes into play next, followed by a discussion on the need for developed states to change patterns of behavior in order to achieve sustainability. Finally, nuclear power and liquefied natural gas are reviewed and rejected as power options for the region.

  3. EMISSIONS REDUCTION DATA FOR GRID-CONNECTED PHOTOVOLTAIC POWER SYSTEMS

    EPA Science Inventory

    This study measured the pollutant emission reduction potential of 29 photovoltaic (PV) systems installed on residential and commercial building rooftops across the U.S. from 1993 through 1997. The U.S. Environmental Protection Agency (EPA) and 21 electric power companies sponsor...

  4. Wind Power in Ontario: Its Contribution to the Electricity Grid

    ERIC Educational Resources Information Center

    Rowlands, Ian H.; Jernigan, Carey

    2008-01-01

    The purpose of this article is to investigate wind turbine production, the variability of that production, and the relationship between output and system-wide demand. A review of the literature reveals that a variety of measures (and methods) to explore the variability of wind power production exist. Attention then turns to the province of Ontario…

  5. Low-energy hydraulic fracturing wastewater treatment via AC powered electrocoagulation with biochar.

    PubMed

    Lobo, Fernanda Leite; Wang, Heming; Huggins, Tyler; Rosenblum, James; Linden, Karl G; Ren, Zhiyong Jason

    2016-05-15

    Produced and flowback waters are the largest byproducts associated with unconventional oil and gas exploration and production. Sustainable and low cost technologies are needed to treat and reuse this wastewater to avoid the environmental problems associated with current management practices (i.e., deep well injection). This study presents a new process to integrate AC-powered electrocoagulation (EC) with granular biochar to dramatically reduce energy use and electrode passivation while achieving high treatment efficiency. Results show achieving a 99% turbidity and TSS removal for the AC-EC-biochar system only used 0.079 kWh/m(3) or 0.15 kWh/kg TSS, which is 70% lower than traditional DC-EC systems and orders of magnitude lower than previous studies. The amount of biochar added positively correlates with energy saving, and further studies are needed to improve organic carbon and salt removal through system integration. PMID:26894291

  6. Reducing the Vulnerability of Electric Power Grids to Terrorist Attacks

    SciTech Connect

    Ross Baldick; Thekla Boutsika; Jin Hur; Manho Joung; Yin Wu; Minqi Zhong

    2009-01-31

    This report describes the development of a cascading outage analyzer that, given an initial disturbance on an electric power system, checks for thermal overloads, under-frequency and over-frequency conditions, and under-voltage conditions that would result in removal of elements from the system. The analyzer simulates the successive tripping of elements due to protective actions until a post-event steady state or a system blackout is reached.

  7. Experimental Evaluation of Electric Power Grid Visualization Tools in the EIOC

    SciTech Connect

    Greitzer, Frank L.; Dauenhauer, Peter M.; Wierks, Tamara G.; Podmore, Robin; Dalton, Angela C.

    2009-12-01

    The present study follows an initial human factors evaluation of four electric power grid visualization tools and reports on an empirical evaluation of two of the four tools: Graphical Contingency Analysis, and Phasor State Estimator. The evaluation was conducted within specific experimental studies designed to measure the impact on decision making performance.

  8. AC/DC Power Systems with Applications for future Lunar/Mars base and Crew Exploration Vehicle

    NASA Technical Reports Server (NTRS)

    Chowdhury, Badrul H.

    2005-01-01

    ABSTRACT The Power Systems branch at JSC faces a number of complex issues as it readies itself for the President's initiative on future space exploration beyond low earth orbit. Some of these preliminary issues - those dealing with electric power generation and distribution on board Mars-bound vehicle and that on Lunar and Martian surface may be summarized as follows: Type of prime mover - Because solar power may not be readily available on parts of the Lunar/Mars surface and also during the long duration flight to Mars, the primary source of power will most likely be nuclear power (Uranium fuel rods) with a secondary source of fuel cell (Hydrogen supply). The electric power generation source - With nuclear power being the main prime mover, the electric power generation source will most likely be an ac generator at a yet to be determined frequency. Thus, a critical issue is whether the generator should generate at constant or variable frequency. This will decide what type of generator to use - whether it is a synchronous machine, an asynchronous induction machine or a switched reluctance machine. The type of power distribution system - the distribution frequency, number of wires (3- wire, 4-wire or higher), and ac/dc hybridization. Building redundancy and fault tolerance in the generation and distribution sub-systems so that the system is safe; provides 100% availability to critical loads; continues to operate even with faulted sub-systems; and requires minimal maintenance. This report descril_es results of a summer faculty fellowship spent in the Power Systems Branch with the specific aim of investigating some of the lessons learned in electric power generation and usage from the terrestrial power systems industry, the aerospace industry as well as NASA's on-going missions so as to recommend novel surface and vehicle-based power systems architectures in support of future space exploration initiatives. A hybrid ac/dc architecture with source side and load side

  9. An Overview of Power Electronics Applications in Fuel Cell Systems: DC and AC Converters

    PubMed Central

    Ali, M. S.; Kamarudin, S. K.; Masdar, M. S.; Mohamed, A.

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  10. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    PubMed

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  11. A New Regulation for Rural Power Grid Low-Voltage Controlling

    NASA Astrophysics Data System (ADS)

    Xian, L.; Wu, L. Z.; Yu, G. K.; Zhou, H.

    To solve the low voltage problem of rural power grid, this paper proposed a new mode of regulating voltage through substation, line and distribute substation. Through establish the mathematics module to analysis the three joint voltage regulation, and the control strategy of three joint regulation is also given in this paper. Through three joint voltage and reactive power compensation regulation, the voltage quality would be improved and the network loss would be reduced.

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

    NASA Astrophysics Data System (ADS)

    Cohn, Julie A.

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

  13. Power-based control with integral action for wind turbines connected to the grid

    NASA Astrophysics Data System (ADS)

    Peña, R. R.; Fernández, R. D.; Mantz, R. J.; Battaiotto, P. E.

    2015-10-01

    In this paper, a power shaping control with integral action is employed to control active and reactive powers of wind turbines connected to the grid. As it is well known, power shaping allows finding a Lyapunov function which ensures stability. In contrast to other passivity-based control theories, the power shaping controller design allows to use easily measurable variables, such as voltages and currents which simplify the physical interpretation and, therefore, the controller synthesis. The strategy proposed is evaluated in the context of severe operating conditions, such as abrupt changes in the wind speed and voltage drops.

  14. Effect of Smart Storage in Ubiquitous Power Grid on Frequency Control

    NASA Astrophysics Data System (ADS)

    Ota, Yutaka; Taniguchi, Haruhito; Nakajima, Tatsuhito; Liyanage, Kithsiri M.; Shimizu, Koichiro; Masuta, Taisuke; Baba, Jumpei; Yokoyama, Akihiko

    Penetrating large amount of renewable energy sources into power system, battery energy storage performs an important role for smoothing their natural intermittency, ensuring grid-wide frequency stability, and suppressing voltage rise caused by reverse power flow. The ubiquitous power grid is one of the concepts as a smart grid in Japanese context, where the total battery capacity can be optimized by coordinating renewable energy sources, controllable distributed generators, and controllable loads on demand side, for example, heat pump based water heater with heat storage, and plug-in hybrid vehicle or electric vehicle with onboard battery, and so on. These controllable devices behave as an autonomous distributed smart storage by charging or discharging against the power system frequency measurement as paying attention to user convenience. In this paper, the effects of the autonomous distributed smart storage on load frequency control of the bulk power system are investigated. And the authors propose a simple coordinated control scheme to the spinning reserve of the thermal power generator.

  15. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  16. Hamiltonian-Based Model to Describe the Nonlinear Physics of Cascading Failures in Power-Grid Networks

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Motter, Adilson

    A local disturbance to the state of a power-grid system can trigger a protective response that disables some grid components, which leads to further responses, and may finally result in large-scale failures. In this talk, I will introduce a Hamiltonian-like model of cascading failures in power grids. This model includes the state variables of generators, which are determined by the nonlinear swing equations and power-flow equations, as well as the on/off status of the network components. This framework allows us to view a cascading failure in the power grid as a phase-space transition from a fixed point with high energy to a fixed point with lower energy. Using real power-grid networks, I will demonstrate that possible cascade outcomes can be predicted by analyzing the stability of the system's equilibria. This work adds an important new dimension to the current understanding of cascading failures.

  17. The influence of bending strains on AC power losses in multifilamentary BSCCO-2223/Ag tapes

    NASA Astrophysics Data System (ADS)

    Tsukamoto, O.; Ciszek, M.; Suzuki, H.; Ogawa, J.

    2006-08-01

    Recent advances in the manufacturing of multifilamentary high temperature superconducting composite wires allow for wider practical applications of the conductors, e.g. in power transmission cables, transformers and motors. The wires, based mainly on BSCCO-2223 and YBCO-123 cuprates, are used in the forms of variously shaped coils; therefore they are subjected to different kinds of mechanical stresses and strains. These, in turn, lead to some changes in the physical parameters of the superconducting material, mainly in the critical current density, and thus in the dissipated electromagnetic energy, when subjected to changing magnetic fields and transport currents. In this work we report some experimental results related to the AC loss characteristics of Bi-2223/Ag multifilamentary tapes and their dependences on bending strains. These losses are compared to the losses of virgin, straight tapes. The total AC losses, i.e. transport current and magnetization losses, in the Bi-2223/Ag tapes, were measured by means of the electrical and calorimetric methods. The experimental data obtained are compared with the critical state model predictions for AC loss behaviour in the experimental conditions presented here.

  18. Single and three-phase AC losses in HTS superconducting power transmission line prototype cables

    SciTech Connect

    Daney, D.E.; Boenig, H.J.; Maley, M.P.; Coulter, J.Y.; Fleshler, S.

    1997-11-01

    AC losses in two, one-meter-long lengths of HTS prototype multi-strand conductors (PMC`s) are measured with a temperature-difference calorimeter. Both single-phase and three-phase losses are examined with ac currents up to 1,000 A rms. The calorimeter, designed specifically for these measurements, has a precision of 1 mW. PMC {number_sign}1 has two helically-wound, non-insulated layers of HTS tape (19 tapes per layer), each layer wrapped with opposite pitch. PMC {number_sign}2 is identical except for insulation between the layers. The measured ac losses show no significant effect of interlayer insulation and depend on about the third power of the current--a result in agreement with the Bean-Norris model adapted to the double-helix configuration. The three-phase losses are a factor of two higher than those exhibited by a single isolated conductor, indicating a significant interaction between phases.

  19. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    NASA Astrophysics Data System (ADS)

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  20. Plasma antennas driven by 5–20 kHz AC power supply

    SciTech Connect

    Zhao, Jiansen Chen, Yuli; Sun, Yang; Wu, Huafeng; Liu, Yue; Yuan, Qiumeng

    2015-12-15

    The experiments described in this work were performed with the aim of introducing a new plasma antenna that was excited by a 5–20 kHz alternating current (AC) power supply, where the antenna was transformed into a U-shape. The results show that the impedance, voltage standing-wave ratio (VSWR), radiation pattern and gain characteristics of the antenna can be controlled rapidly by varying not only the discharge power, but also by varying the discharge frequency in the range from 5 to 20 kHz. When the discharge frequency is adjusted from 10 to 12 kHz, the gain is higher within a relatively broad frequency band and the switch-on time is less than 1 ms when the discharge power is less than 5 W, meaning that the plasma antenna can be turned on and off rapidly.

  1. Development of an AC power source for CSEM method using full-bridge switching configuration

    NASA Astrophysics Data System (ADS)

    Indrasari, Widyaningrum; Srigutomo, Wahyu; Djamal, Mitra; S, Rahmondia N.

    2015-04-01

    The electromagnetic (EM) method has been widely used in geophysical surveys. It is a non-destructive method that utilizes electromagnetic waves in characterizing subsurface profiles. Generally, EM method can be divided into passive EM and active EM. The passive EM uses the natural electromagnetic field sources, while the active EM or Controlled Source EM (CSEM) uses artificial source to generate electromagnetic wave. In this paper, we present the development of AC power source for CSEM transmitter. As the power source we used AC source with sine wave signal. To satisfy a high power and high voltage in the equipment, we used the full-bridge configuration switching. It works on 990 Hz maximum frequency, and can deliver maximum current of 1.9 A at 620 V. The switching is controlled by microcontroller using Pulse Width Modulation (PWM) and the driver of inverter is built using IGBT. The output frequency can be varied from 1 Hz to 990 Hz. For varied frequencies the harmonic distortion is different due to switching speed. As frequency increase the harmonic distortion also increase. We found that the total harmonic distortion can be reduced to 1 % at the output with 330 Hz.

  2. Simulation analysis of three-phase current type AC-to-DC converter with high power factor

    SciTech Connect

    Okui, Yoshiaki; Yamada, Hajime

    1997-03-01

    A new three-phase current type AC-to-DC converter has been developed by the authors. This paper describes the principle of the circuit operation and the circuit configuration of the AC-to-DC converter controlled by PWM. Simulation analysis of each waveform, such as AC and DC voltages and currents, are calculated by Euler`s method. The simulated values of the total power factor agreed with the measured values within the difference of 5.8% on the condition of full load, 10kW. When the AC side voltage is unbalanced, it is found by simulation that the total harmonic distortion controlled by both feedforward control and AC side current feedback control (proportion gain, k{sub 4} = 1) is restrained at only 38% compared with only feedforward control (k{sub 4} = 0).

  3. Vulnerability of the large-scale future smart electric power grid

    NASA Astrophysics Data System (ADS)

    Nasiruzzaman, A. B. M.; Pota, H. R.; Akter, Most. Nahida

    2014-11-01

    The changing power flow pattern of the power system, with inclusion of large-scale renewable energy sources in the distribution side of the network, has been modeled by complex network framework based bidirectional graph. The bidirectional graph accommodates the reverse power flowing back from the distribution side to the grid in the model as a reverse edge connecting two nodes. The capacity of the reverse edge is equal to the capacity of the existing edge between the nodes in the forward directional nominal graph. Increased path in the combined model, built to facilitate grid reliability and efficiency, may serve as a bottleneck in practice with removal of certain percentage of nodes or edges. The effect of removal of critical elements has been analyzed in terms of increased path length, connectivity loss, load loss, and number of overloaded lines.

  4. Development of a smart DC grid model

    NASA Astrophysics Data System (ADS)

    Dalimunthe, Amty Ma'rufah Ardhiyah; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made

    2016-03-01

    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 a 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.

  5. The Emerging Interdependence of the Electric Power Grid & Information and Communication Technology

    SciTech Connect

    Taft, Jeffrey D.; Becker-Dippmann, Angela S.

    2015-08-01

    This paper examines the implications of emerging interdependencies between the electric power grid and Information and Communication Technology (ICT). Over the past two decades, electricity and ICT infrastructure have become increasingly interdependent, driven by a combination of factors including advances in sensor, network and software technologies and progress in their deployment, the need to provide increasing levels of wide-area situational awareness regarding grid conditions, and the promise of enhanced operational efficiencies. Grid operators’ ability to utilize new and closer-to-real-time data generated by sensors throughout the system is providing early returns, particularly with respect to management of the transmission system for purposes of reliability, coordination, congestion management, and integration of variable electricity resources such as wind generation.

  6. Probability-Based Software for Grid Optimization: Improved Power System Operations Using Advanced Stochastic Optimization

    SciTech Connect

    2012-02-24

    GENI Project: Sandia National Laboratories is working with several commercial and university partners to develop software for market management systems (MMSs) that enable greater use of renewable energy sources throughout the grid. MMSs are used to securely and optimally determine which energy resources should be used to service energy demand across the country. Contributions of electricity to the grid from renewable energy sources such as wind and solar are intermittent, introducing complications for MMSs, which have trouble accommodating the multiple sources of price and supply uncertainties associated with bringing these new types of energy into the grid. Sandia’s software will bring a new, probability-based formulation to account for these uncertainties. By factoring in various probability scenarios for electricity production from renewable energy sources in real time, Sandia’s formula can reduce the risk of inefficient electricity transmission, save ratepayers money, conserve power, and support the future use of renewable energy.

  7. Effect of grid design on Cs-Ba tacitron operation and its application to space nuclear power systems

    NASA Astrophysics Data System (ADS)

    Wernsman, Bernard; El-Genk, Mohamed S.

    1995-01-01

    A study of the modulation capabilities of the Cs-Ba tacitron with different grid designs was made. Results showed the ignition grid potential to be independent of grid design at a modulation frequency, fg, of 1 kHz. At fg =22 kHz, discharge ignition with a 26% transparent grid was harder to achieve than at fg=1 kHz. The grid design greatly affects not only the extinguishing potential, but also the forward voltage drop. Increasing the grid transparency and/or aperture size makes it harder to extinguish the discharge (increases ‖ Vg- ‖), but lowers the forward voltage drop across the tacitron. Increasing fg also increases ‖ Vg- ‖, but lowers the forward voltage drop across the tacitron. Increasing fg also increases ‖ Vg- ‖ and lowers the range of Cs pressure for stable current modulation. For a TOPAZ-II type space nuclear reactor power system (SNPS), the lowest electrical power consumption by Cs-Ba tacitrons inverters, employing 34% transparent, 0.5 mm diameter holed grid and operating at IC=10 A or 20 A and fg=1 kHz, is ˜6.5% of the total system output power. This electrical power consumption includes that of the grid power supply and the power loss in the tacitron during discharge.

  8. Numerical study on AC loss characteristics of superconducting power transmission cables comprising coated conductors with magnetic substrates

    NASA Astrophysics Data System (ADS)

    Amemiya, N.; Nakahata, M.

    2007-10-01

    Electromagnetic field analyses were made for mono-layer conductors comprising coated conductors for superconducting power transmission cables in order to evaluate their AC loss characteristics. We focused on the magnetic properties of the substrates of coated conductors. The current distribution in each coated conductor and the magnetic flux profile around each coated conductor were visualized. The influence of relative permeability and the space between coated conductors on the AC loss characteristics of mono-layer conductors were studied based on the visualized current and magnetic flux distributions. The influence of a saturated magnetic property on a calculated AC loss was also discussed.

  9. Voltage Stability Impact of Grid-Tied Photovoltaic Systems Utilizing Dynamic Reactive Power Control

    NASA Astrophysics Data System (ADS)

    Omole, Adedamola

    Photovoltaic (PV) DGs can be optimized to provide reactive power support to the grid, although this feature is currently rarely utilized as most DG systems are designed to operate with unity power factor and supply real power only to the grid. In this work, the voltage stability of a power system embedded with PV DG is examined in the context of the high reactive power requirement after a voltage sag or fault. A real-time dynamic multi-function power controller that enables renewable source PV DGs to provide the reactive power support necessary to maintain the voltage stability of the microgrid, and consequently, the wider power system is proposed. The loadability limit necessary to maintain the voltage stability of an interconnected microgrid is determined by using bifurcation analysis to test for the singularity of the network Jacobian and load differential equations with and without the contribution of the DG. The maximum and minimum real and reactive power support permissible from the DG is obtained from the loadability limit and used as the limiting factors in controlling the real and reactive power contribution from the PV source. The designed controller regulates the voltage output based on instantaneous power theory at the point-of-common coupling (PCC) while the reactive power supply is controlled by means of the power factor and reactive current droop method. The control method is implemented in a modified IEEE 13-bus test feeder system using PSCADRTM power system analysis software and is applied to the model of a Tampa ElectricRTM PV installation at Lowry Park Zoo in Tampa, FL. This dissertation accomplishes the systematic analysis of the voltage impact of a PV DG-embedded power distribution system. The method employed in this work bases the contribution of the PV resource on the voltage stability margins of the microgrid rather than the commonly used loss-of-load probability (LOLP) and effective load-carrying capability (ELCC) measures. The results of

  10. Quantifying baseline emission factors of air pollutants in China's regional power grids.

    PubMed

    Cai, Wenjia; Wang, Can; Jin, Zhugang; Chen, Jining

    2013-04-16

    Drawing lessons from the clean development mechanism (CDM), this paper developed a combined margin methodology to quantify baseline emission factors of air pollutants in China's regional power grids. The simple average of baseline emission factors of SO2, NOX, and PM2.5 in China's six power grids in 2010 were respectively 1.91 kg/MWh, 1.83 kg/MWh and 0.32 kg/MWh. Several low-efficient mitigation technologies, such as low nitrogen oxide burner (LNB), were suggested to be replaced or used together with other technologies in order to virtually decrease the grid's emission factor. The synergies between GHG and air pollution mitigation in China's power sector was also notable. It is estimated that in 2010, that every 1% CO2 reduction in China's power generation sector resulted in the respective coreduction of 1.1%, 0.5%, and 0.8% of SO2, NOX, and PM2.5. Wind is the best technology to achieve the largest amount of coabatement in most parts of China. This methodology is recommended to be used in making comprehensive air pollution control strategies and in cobenefits analysis in future CDM approval processes. PMID:23461797

  11. Integrating Solar Power onto the Electric Grid - Bridging the Gap between Atmospheric Science, Engineering and Economics

    NASA Astrophysics Data System (ADS)

    Ghonima, M. S.; Yang, H.; Zhong, X.; Ozge, B.; Sahu, D. K.; Kim, C. K.; Babacan, O.; Hanna, R.; Kurtz, B.; Mejia, F. A.; Nguyen, A.; Urquhart, B.; Chow, C. W.; Mathiesen, P.; Bosch, J.; Wang, G.

    2015-12-01

    One of the main obstacles to high penetrations of solar power is the variable nature of solar power generation. To mitigate variability, grid operators have to schedule additional reliability resources, at considerable expense, to ensure that load requirements are met by generation. Thus despite the cost of solar PV decreasing, the cost of integrating solar power will increase as penetration of solar resources onto the electric grid increases. There are three principal tools currently available to mitigate variability impacts: (i) flexible generation, (ii) storage, either virtual (demand response) or physical devices and (iii) solar forecasting. Storage devices are a powerful tool capable of ensuring smooth power output from renewable resources. However, the high cost of storage is prohibitive and markets are still being designed to leverage their full potential and mitigate their limitation (e.g. empty storage). Solar forecasting provides valuable information on the daily net load profile and upcoming ramps (increasing or decreasing solar power output) thereby providing the grid advance warning to schedule ancillary generation more accurately, or curtail solar power output. In order to develop solar forecasting as a tool that can be utilized by the grid operators we identified two focus areas: (i) develop solar forecast technology and improve solar forecast accuracy and (ii) develop forecasts that can be incorporated within existing grid planning and operation infrastructure. The first issue required atmospheric science and engineering research, while the second required detailed knowledge of energy markets, and power engineering. Motivated by this background we will emphasize area (i) in this talk and provide an overview of recent advancements in solar forecasting especially in two areas: (a) Numerical modeling tools for coastal stratocumulus to improve scheduling in the day-ahead California energy market. (b) Development of a sky imager to provide short term

  12. Complex Dynamics of the Power Transmission Grid (and other Critical Infrastructures)

    NASA Astrophysics Data System (ADS)

    Newman, David

    2015-03-01

    Our modern societies depend crucially on a web of complex critical infrastructures such as power transmission networks, communication systems, transportation networks and many others. These infrastructure systems display a great number of the characteristic properties of complex systems. Important among these characteristics, they exhibit infrequent large cascading failures that often obey a power law distribution in their probability versus size. This power law behavior suggests that conventional risk analysis does not apply to these systems. It is thought that much of this behavior comes from the dynamical evolution of the system as it ages, is repaired, upgraded, and as the operational rules evolve with human decision making playing an important role in the dynamics. In this talk, infrastructure systems as complex dynamical systems will be introduced and some of their properties explored. The majority of the talk will then be focused on the electric power transmission grid though many of the results can be easily applied to other infrastructures. General properties of the grid will be discussed and results from a dynamical complex systems power transmission model will be compared with real world data. Then we will look at a variety of uses of this type of model. As examples, we will discuss the impact of size and network homogeneity on the grid robustness, the change in risk of failure as generation mix (more distributed vs centralized for example) changes, as well as the effect of operational changes such as the changing the operational risk aversion or grid upgrade strategies. One of the important outcomes from this work is the realization that ``improvements'' in the system components and operational efficiency do not always improve the system robustness, and can in fact greatly increase the risk, when measured as a risk of large failure.

  13. RTDS-Based Design and Simulation of Distributed P-Q Power Resources in Smart Grid

    NASA Astrophysics Data System (ADS)

    Taylor, Zachariah David

    In this Thesis, we propose to utilize a battery system together with its power electronics interfaces and bidirectional charger as a distributed P-Q resource in power distribution networks. First, we present an optimization-based approach to operate such distributed P-Q resources based on the characteristics of the battery and charger system as well as the features and needs of the power distribution network. Then, we use the RTDS Simulator, which is an industry-standard simulation tool of power systems, to develop two RTDS-based design approaches. The first design is based on an ideal four-quadrant distributed P-Q power resource. The second design is based on a detailed four-quadrant distributed P-Q power resource that is developed using power electronics components. The hardware and power electronics circuitry as well as the control units are explained for the second design. After that, given the two-RTDS designs, we conducted extensive RTDS simulations to assess the performance of the designed distributed P-Q Power Resource in an IEEE 13 bus test system. We observed that the proposed design can noticeably improve the operational performance of the power distribution grid in at least four key aspects: reducing power loss, active power peak load shaving at substation, reactive power peak load shaving at substation, and voltage regulation. We examine these performance measures across three design cases: Case 1: There is no P-Q Power Resource available on the power distribution network. Case 2: The installed P-Q Power Resource only supports active power, i.e., it only utilizes its battery component. Case 3: The installed P-Q Power Resource supports both active and reactive power, i.e., it utilizes both its battery component and its power electronics charger component. In the end, we present insightful interpretations on the simulation results and suggest some future works.

  14. A self-powered AC magnetic sensor based on piezoelectric nanogenerator

    NASA Astrophysics Data System (ADS)

    Yu, Aifang; Song, Ming; Zhang, Yan; Kou, Jinzong; Zhai, Junyi; Wang, Zhong Lin

    2014-11-01

    An AC magnetic field, which is a carrier of information, is distributed everywhere and is continuous. How to use and detect this field has been an ongoing topic over the past few decades. Conventional magnetic sensors are usually based on the Hall Effect, the fluxgate, a superconductor quantum interface or magnetoelectric or magnetoresistive sensing. Here, a flexible, simple, low-cost and self-powered active piezoelectric nanogenerator (NG) is successfully demonstrated as an AC magnetic field sensor at room temperature. The amplitude and frequency of a magnetic field can both be accurately sensed by the NG. The output voltage of the NG has a good linearity with a measured magnetic field. The detected minute magnetic field is as low as 1.2 × 10-7 tesla, which is 400 times greater than a commercial magnetic sensor that uses the Hall Effect. In comparison to the existing technologies, an NG is a room-temperature self-powered active sensor that is very simple and very cheap for practical applications.

  15. A self-powered AC magnetic sensor based on piezoelectric nanogenerator.

    PubMed

    Yu, Aifang; Song, Ming; Zhang, Yan; Kou, Jinzong; Zhai, Junyi; Lin Wang, Zhong

    2014-11-14

    An AC magnetic field, which is a carrier of information, is distributed everywhere and is continuous. How to use and detect this field has been an ongoing topic over the past few decades. Conventional magnetic sensors are usually based on the Hall Effect, the fluxgate, a superconductor quantum interface or magnetoelectric or magnetoresistive sensing. Here, a flexible, simple, low-cost and self-powered active piezoelectric nanogenerator (NG) is successfully demonstrated as an AC magnetic field sensor at room temperature. The amplitude and frequency of a magnetic field can both be accurately sensed by the NG. The output voltage of the NG has a good linearity with a measured magnetic field. The detected minute magnetic field is as low as 1.2 × 10(-7) tesla, which is 400 times greater than a commercial magnetic sensor that uses the Hall Effect. In comparison to the existing technologies, an NG is a room-temperature self-powered active sensor that is very simple and very cheap for practical applications. PMID:25333328

  16. Effect of AC target power on AlN film quality

    SciTech Connect

    Knisely, Katherine Grosh, Karl

    2014-09-01

    The influence of alternating current (AC) target power on film stress, roughness, and x-ray diffraction rocking curve full width half maximum (FWHM) was examined for AlN films deposited using S-gun magnetron sputtering on insulative substrates consisting of Si wafers with 575 nm thermal oxide. As the AC target power was increased from 5 to 8 kW, the deposition rate increased from 9.3 to 15.9 A/s, film stress decreased from 81 to −170 MPa, and the rocking curve FWHM increased from 0.98 to 1.03°. AlN film behavior is observed to change with target life; films deposited at 200 kWh target life were approximately 40 MPa more compressive and had 0.02° degree higher rocking curve FWHM values than films deposited at 130 kWh. AlN films deposited in two depositions were compared with films deposited in a single deposition, in order to better characterize the growth behavior and properties of AlN films deposited on an existing AlN film, which is not well understood. Two deposition films, when compared with single deposition films, showed no variation in residual stress trends or grain size behavior, but the average film roughness increased from 0.7 to 1.4 nm and rocking curve FWHM values increased by more than 0.25°.

  17. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-24

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  18. Ac resonant charger with charge rate unrelated to preimary power requency

    DOEpatents

    Not Available

    1979-12-07

    An ac resonant charger for a capacitive load, such as a pulse forming network (PFN), is provided with a variable repetition rate unrelated to the frequency of a multi-phase ac power source by using a control unit to select and couple the phase of the power source to the resonant charger in order to charge the capacitive load with a phase that is the next to begin a half cycle. For optimum range in repetition rate and increased charging voltage, the resonant charger includes a step-up transformer and full-wave rectifier. The next phase selected may then be of either polarity, but is always selected to be of a polarity opposite the polarity of the last phase selected so that the transformer core does not saturate. Thyristors are used to select and couple the correct phase just after its zero crossover in response to a sharp pulse generated by a zero-crossover detector. The thyristor that is turned on then automatically turns off after a full half cycle of its associated phase input. A full-wave rectifier couples the secondary winding of the transformer to the load so that the load capacitance is always charged with the same polarity.

  19. AC Resonant charger with charge rate unrelated to primary power frequency

    DOEpatents

    Watson, Harold

    1982-01-01

    An AC resonant charger for a capacitive load, such as a PFN, is provided with a variable repetition rate unrelated to the frequency of a multi-phase AC power source by using a control unit to select and couple the phase of the power source to the resonant charger in order to charge the capacitive load with a phase that is the next to begin a half cycle. For optimum range in repetition rate and increased charging voltage, the resonant charger includes a step-up transformer and full-wave rectifier. The next phase selected may then be of either polarity, but is always selected to be of a polarity opposite the polarity of the last phase selected so that the transformer core does not saturate. Thyristors are used to select and couple the correct phase just after its zero crossover in response to a sharp pulse generated by a zero-crossover detector. The thyristor that is turned on then automatically turns off after a full half cycle of its associated phase input. A full-wave rectifier couples the secondary winding of the transformer to the load so that the load capacitance is always charged with the same polarity.

  20. Inspection Robot Based Mobile Sensing and Power Line Tracking for Smart Grid.

    PubMed

    Byambasuren, Bat-Erdene; Kim, Donghan; Oyun-Erdene, Mandakh; Bold, Chinguun; Yura, Jargalbaatar

    2016-01-01

    Smart sensing and power line tracking is very important in a smart grid system. Illegal electricity usage can be detected by remote current measurement on overhead power lines using an inspection robot. There is a need for accurate detection methods of illegal electricity usage. Stable and correct power line tracking is a very prominent issue. In order to correctly track and make accurate measurements, the swing path of a power line should be previously fitted and predicted by a mathematical function using an inspection robot. After this, the remote inspection robot can follow the power line and measure the current. This paper presents a new power line tracking method using parabolic and circle fitting algorithms for illegal electricity detection. We demonstrate the effectiveness of the proposed tracking method by simulation and experimental results. PMID:26907274

  1. Analysis of cascading failure in electric grid based on power flow entropy

    NASA Astrophysics Data System (ADS)

    Bao, Z. J.; Cao, Y. J.; Wang, G. Z.; Ding, L. J.

    2009-08-01

    Large-scale blackouts are an intrinsic drawback of electric power transmission grids. Here we propose a concept of power flow entropy to quantify the overall heterogeneity of load distribution and then investigate the relationship between the power flow entropy and cascading failure. Simulation results, from the small-world 300-node test system and the IEEE 300-bus system, show that the power flow entropy has close relations with the cascading failure in terms of both the dynamic propagation course and the static blackout size. Particularly, at the early stage of failure spreading the potential large blackout can be identified according to the power flow entropy. The power flow entropy can serve as an index not only for long-term planning, but also for short-term operational defense to large-scale blackouts.

  2. Inspection Robot Based Mobile Sensing and Power Line Tracking for Smart Grid

    PubMed Central

    Byambasuren, Bat-erdene; Kim, Donghan; Oyun-Erdene, Mandakh; Bold, Chinguun; Yura, Jargalbaatar

    2016-01-01

    Smart sensing and power line tracking is very important in a smart grid system. Illegal electricity usage can be detected by remote current measurement on overhead power lines using an inspection robot. There is a need for accurate detection methods of illegal electricity usage. Stable and correct power line tracking is a very prominent issue. In order to correctly track and make accurate measurements, the swing path of a power line should be previously fitted and predicted by a mathematical function using an inspection robot. After this, the remote inspection robot can follow the power line and measure the current. This paper presents a new power line tracking method using parabolic and circle fitting algorithms for illegal electricity detection. We demonstrate the effectiveness of the proposed tracking method by simulation and experimental results. PMID:26907274

  3. Solar Energy Grid Integration Systems. Final Report of the Princeton Power Systems Development of the 100kW Demand Response Inverter.

    SciTech Connect

    Bower, Ward Isaac; Heavener, Paul; Sena-Henderson, Lisa; Hammell, Darren; Holveck, Mark; David, Carolyn; Akhil, Abbas Ali; Gonzalez, Sigifredo

    2012-01-01

    Initiated in 2008, the Solar Energy Grid Integration (SEGIS) program is a partnership involving the U.S. Department of Energy, Sandia National Laboratories, electric utilities, academic institutions and the private sector. Recognizing the need to diversify the nation's energy portfolio, the SEGIS effort focuses on specific technologies needed to facilitate the integration of large-scale solar power generation into the nation's power grid Sandia National Laboratories (SNL) awarded a contract to Princeton Power Systems, Inc., (PPS) to develop a 100kW Advanced AC-link SEGIS inverter prototype under the Department of Energy Solar Energy Technologies Program for near-term commercial applications. This SEGIS initiative emphasizes the development of advanced inverters, controllers, communications and other balance-of-system components for photovoltaic (PV) distributed power applications. The SEGIS Stage 3 Contract was awarded to PPS on July 28, 2010. PPS developed and implemented a Demand Response Inverter (DRI) during this three-stage program. PPS prepared a 'Site Demonstration Conference' that was held on September 28, 2011, to showcase the cumulative advancements. This demo of the commercial product will be followed by Underwriters Laboratories, Inc., certification by the fourth quarter of 2011, and simultaneously the customer launch and commercial production sometime in late 2011 or early 2012. This final report provides an overview of all three stages and a full-length reporting of activities and accomplishments in Stage 3.

  4. Message passing for integrating and assessing renewable generation in a redundant power grid

    SciTech Connect

    Zdeborova, Lenka; Backhaus, Scott; Chertkov, Michael

    2009-01-01

    A simplified model of a redundant power grid is used to study integration of fluctuating renewable generation. The grid consists of large number of generator and consumer nodes. The net power consumption is determined by the difference between the gross consumption and the level of renewable generation. The gross consumption is drawn from a narrow distribution representing the predictability of aggregated loads, and we consider two different distributions representing wind and solar resources. Each generator is connected to D consumers, and redundancy is built in by connecting R {le} D of these consumers to other generators. The lines are switchable so that at any instance each consumer is connected to a single generator. We explore the capacity of the renewable generation by determining the level of 'firm' generation capacity that can be displaced for different levels of redundancy R. We also develop message-passing control algorithm for finding switch sellings where no generator is overloaded.

  5. The vulnerabilities of the power-grid system: renewable microgrids as an alternative source of energy.

    PubMed

    Meyer, Victor; Myres, Charles; Bakshi, Nitin

    2010-03-01

    The objective of this paper is to analyse the vulnerabilities of current power-grid systems and to propose alternatives to using fossil fuel power generation and infrastructure solutions in the form of microgrids, particularly those from renewable energy sources. One of the key potential benefits of microgrids, apart from their inherent sustainability and ecological advantages, is increased resilience. The analysis is targeted towards the context of business process outsourcing in India. However, much of the research on vulnerabilities has been derived from the USA and as such many of the examples cite vulnerabilities in the USA and other developed economies. Nevertheless, the vulnerabilities noted are to a degree common to all grid systems, and so the analysis may be more broadly applicable. PMID:20494879

  6. Grid Impacts of Wind Power Variability: Recent Assessments from a Variety of Utilities in the United States; Preprint

    SciTech Connect

    Parsons, B.; Milligan, M.; Smith, J. C.; DeMeo, E.; Oakleaf, B.; Wolf, K.; Schuerger, M.; Zavadil, R.; Ahlstrom, M.; Nakafuji, D. Y.

    2006-07-01

    Because of wind power's unique characteristics, many concerns are based on the increased variability that wind contributes to the grid, and most U.S. studies have focused on this aspect of wind generation. Grid operators are also concerned about the ability to predict wind generation over several time scales. In this report, we quantify the physical impacts and costs of wind generation on grid operations and the associated costs.

  7. Genetic algorithms for optimal reactive power compensation planning on the national grid system

    NASA Astrophysics Data System (ADS)

    Pilgrim, J. D.

    This work investigates the use of Genetic Algorithms (GAs) for optimal Reactive power Compensation Planning (RCP) of practical power systems. In particular, RCP of the transmission system of England and Wales as owned and operated by National Grid is considered. The GA is used to simultaneously solve both the siting problem---optimisation of the installation of new devices---and the operational problem---optimisation of preventive transformer taps and the controller characteristics of dynamic compensation devices. A computer package called Genetic Compensation Placement (GCP) has been developed which uses an Integer coded GA (IGA) to solve the RCP problem. The RCP problem is implemented as a multi-objective optimisation: in the interests of security, the number of system and operational constraint violations and the deviation of the busbar voltages from the ideal are all minimised for the base (intact) case and the contingent cases. In the interests of cost reduction, the reactive power cost is minimised for the base case. The reactive power cost encompasses the costs incurred from the installation of reactive power sources and the utilisation of new and existing dynamic reactive power compensation devices. GCP is compared to SCORPION (a planning program currently being used by National Grid) which uses a combination of linear programming and heuristic back-tracking. Results are presented for a practical test system developed with the cooperation of National Grid, and it is found that GCP produces solutions that are cheaper than solutions found by SCORPION and perform extremely well: an improvement in voltage profiles, a decrease in complex power mismatches, and a reduction in MVolt Amps-reactive (VAr) utilisation were observed.

  8. Increased deposition of polychlorinated biphenyls (PCBs) under an AC high-voltage power line

    NASA Astrophysics Data System (ADS)

    Öberg, Tomas; Peltola, Pasi

    2009-12-01

    There is considerable public concern regarding the potential risks to health of electromagnetic fields in general and high-voltage power lines in particular. As epidemiological findings are not supported by a clearly defined mechanism of direct magnetic field interactions with the human body, potential indirect effects are of interest. It has been suggested that an increased exposure to chemical pollutants could occur near high-voltage power lines due to formation and deposition of charged aerosols. The current study reports empirical evidence that seems to support this hypothesis. The deposition of 18 congeners of polychlorinated biphenyls (PCBs) was studied by collecting samples of pine needles under a 400 kV AC power line and at reference sites in the vicinity. Compared to the reference sites, the average deposition of PCB congeners under the power line was almost double. This difference between the two groups of samples was statistically significant. While it is premature to draw any conclusions regarding the human exposure near high-voltage power lines, the issue deserves attention and further investigations.

  9. 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.

  10. Modeling Framework and Validation of a Smart Grid and Demand Response System for Wind Power Integration

    SciTech Connect

    Broeer, Torsten; Fuller, Jason C.; Tuffner, Francis K.; Chassin, David P.; Djilali, Ned

    2014-01-31

    Electricity generation from wind power and other renewable energy sources is increasing, and their variability introduces new challenges to the power system. The emergence of smart grid technologies in recent years has seen a paradigm shift in redefining the electrical system of the future, in which controlled response of the demand side is used to balance fluctuations and intermittencies from the generation side. This paper presents a modeling framework for an integrated electricity system where loads become an additional resource. The agent-based model represents a smart grid power system integrating generators, transmission, distribution, loads and market. The model incorporates generator and load controllers, allowing suppliers and demanders to bid into a Real-Time Pricing (RTP) electricity market. The modeling framework is applied to represent a physical demonstration project conducted on the Olympic Peninsula, Washington, USA, and validation simulations are performed using actual dynamic data. Wind power is then introduced into the power generation mix illustrating the potential of demand response to mitigate the impact of wind power variability, primarily through thermostatically controlled loads. The results also indicate that effective implementation of Demand Response (DR) to assist integration of variable renewable energy resources requires a diversity of loads to ensure functionality of the overall system.

  11. Geomagnetically induced currents in the Uruguayan high-voltage power grid

    NASA Astrophysics Data System (ADS)

    Caraballo, R.; Sánchez Bettucci, L.; Tancredi, G.

    2013-11-01

    We estimate the influence of the geomagnetically induced currents (GIC) on the Uruguayan electrical distribution grid. The GIC are related to time variations in the geomagnetic field caused by the interaction of the solar wind with the Earth's magnetosphere. These currents may cause several problems in power grids, pipelines, among others. South America is close to the South Atlantic Magnetic Anomaly (SAA). Particle precipitation in the anomaly region could lead to pulsations in the horizontal component of the geomagnetic field, that may contribute to the GIC production. Scarce research has been done to assess the space weather impact on this area. Due to the lack of magnetic field data at the Uruguayan territory, spherical elementary currents system (SECS) was used to interpolate field values with data available from three magnetic observatories located at Vassouras, Trelew and São Martinho da Serra. The simple topology of the Uruguayan power grid provides some advantages in the calculation of GIC. To calculate these currents, a plane wave method combined with a ground conductivity model was used. Estimated GIC suggest peak currents ca. 15 A, at the earthing points of some substations in a 770 km power line during the Halloween Magnetic Storm on 2003 October 29.

  12. Tutorial of Wind Turbine Control for Supporting Grid Frequency through Active Power Control: Preprint

    SciTech Connect

    Aho, J.; Buckspan, A.; Laks, J.; Fleming, P.; Jeong, Y.; Dunne, F.; Churchfield, M.; Pao, L.; Johnson, K.

    2012-03-01

    As wind energy becomes a larger portion of the world's energy portfolio and wind turbines become larger and more expensive, wind turbine control systems play an ever more prominent role in the design and deployment of wind turbines. The goals of traditional wind turbine control systems are maximizing energy production while protecting the wind turbine components. As more wind generation is installed there is an increasing interest in wind turbines actively controlling their power output in order to meet power setpoints and to participate in frequency regulation for the utility grid. This capability will be beneficial for grid operators, as it seems possible that wind turbines can be more effective at providing some of these services than traditional power plants. Furthermore, establishing an ancillary market for such regulation can be beneficial for wind plant owner/operators and manufacturers that provide such services. In this tutorial paper we provide an overview of basic wind turbine control systems and highlight recent industry trends and research in wind turbine control systems for grid integration and frequency stability.

  13. Power Quality Improvement in Bridgeless Ac-Dc Converter Based Multi-output Switched Mode Power Supply

    NASA Astrophysics Data System (ADS)

    Singh, Shihka; Singh, Bhim; Bhuvaneswari, G.; Bist, Vashist

    2014-12-01

    Computer power supplies are required to have multiple isolated regulated dc voltages with low ripple content and high input power factor at the utility interface. A dc-dc converter is used for obtaining these isolated multi-output dc voltages with excellent regulation. In this paper, a non-isolated ac-dc converter is proposed as the first stage converter to obtain a regulated dc output rather than using a simple uncontrolled diode bridge rectifier at the front end. A dc-dc converter is used at the second stage that has a high frequency transformer with multiple secondary windings to obtain different dc voltage levels at the output. The proposed bridgeless converter based power supply is designed using fundamental design equations, and different component values are calculated. Extensive simulations are carried out to demonstrate the improved performance of the proposed bridgeless converter based multi-output computer power supply at varying source voltages and load conditions. Experimental validation of the power supply is carried on a developed hardware prototype, and the test results are compared with the simulated performance for design verification.

  14. Interdisciplinary challenges in the study of power grid resilience and stability and their relation to extreme weather events

    NASA Astrophysics Data System (ADS)

    Heitzig, J.; Fujiwara, N.; Aihara, K.; Kurths, J.

    2014-10-01

    This topical issue collects contributions to the interdisciplinary study of power grid stability in face of increasing volatility of energy production and consumption due to increasing renewable energy infeed and changing climatic conditions. The individual papers focus on different aspects of this field and bring together modern achievements from various disciplines, in particular complex systems science, nonlinear data analysis, control theory, electrical engineering, and climatology. Main topics considered here are prediction and volatility of renewable infeed, modelling and theoretical analysis of power grid topology, dynamics and stability, relationships between stability and complex network topology, and improvements via topological changes or control. Impacts for the design of smart power grids are discussed in detail.

  15. Interdisciplinary challenges in the study of power grid resilience and stability and their relation to extreme weather events

    NASA Astrophysics Data System (ADS)

    Heitzig, J.; Fujiwara, N.; Aihara, K.; Kurths, J.

    2014-09-01

    This topical issue collects contributions to the interdisciplinary study of power grid stability in face of increasing volatility of energy production and consumption due to increasing renewable energy infeed and changing climatic conditions. The individual papers focus on different aspects of this field and bring together modern achievements from various disciplines, in particular complex systems science, nonlinear data analysis, control theory, electrical engineering, and climatology. Main topics considered here are prediction and volatility of renewable infeed, modelling and theoretical analysis of power grid topology, dynamics and stability, relationships between stability and complex network topology, and improvements via topological changes or control. Impacts for the design of smart power grids are discussed in detail.

  16. Grid integration and smart grid implementation of emerging technologies in electric power systems through approximate dynamic programming

    NASA Astrophysics Data System (ADS)

    Xiao, Jingjie

    A key hurdle for implementing real-time pricing of electricity is a lack of consumers' responses. Solutions to overcome the hurdle include the energy management system that automatically optimizes household appliance usage such as plug-in hybrid electric vehicle charging (and discharging with vehicle-to-grid) via a two-way communication with the grid. Real-time pricing, combined with household automation devices, has a potential to accommodate an increasing penetration of plug-in hybrid electric vehicles. In addition, the intelligent energy controller on the consumer-side can help increase the utilization rate of the intermittent renewable resource, as the demand can be managed to match the output profile of renewables, thus making the intermittent resource such as wind and solar more economically competitive in the long run. One of the main goals of this dissertation is to present how real-time retail pricing, aided by control automation devices, can be integrated into the wholesale electricity market under various uncertainties through approximate dynamic programming. What distinguishes this study from the existing work in the literature is that whole- sale electricity prices are endogenously determined as we solve a system operator's economic dispatch problem on an hourly basis over the entire optimization horizon. This modeling and algorithm framework will allow a feedback loop between electricity prices and electricity consumption to be fully captured. While we are interested in a near-optimal solution using approximate dynamic programming; deterministic linear programming benchmarks are use to demonstrate the quality of our solutions. The other goal of the dissertation is to use this framework to provide numerical evidence to the debate on whether real-time pricing is superior than the current flat rate structure in terms of both economic and environmental impacts. For this purpose, the modeling and algorithm framework is tested on a large-scale test case

  17. Global model of a gridded-ion thruster powered by a radiofrequency inductive coil

    SciTech Connect

    Chabert, P.; Arancibia Monreal, J.; Bredin, J.; Popelier, L.; Aanesland, A.

    2012-07-15

    A global (volume-averaged) model of a gridded-ion thruster is proposed. The neutral propellant (xenon gas) is injected into the thruster chamber at a fixed rate and a plasma is generated by circulating a radiofrequency current in an inductive coil. The ions generated in this plasma are accelerated out of the thruster by a pair of DC biased grids. The neutralization downstream is not treated. Xenon atoms also flow out of the thruster across the grids. The model, based on particle and energy balance equations, solves for four global variables in the thruster chamber: the plasma density, the electron temperature, the neutral gas (atom) density, and the neutral gas temperature. The important quantities to evaluate the thruster efficiency and performances are calculated from these variables and from the voltage across the grids. It is found that the mass utilization efficiency rapidly decreases with the gas flow rate. However, the radiofrequency power transfer efficiency increases significantly with the injected gas flow rate. Therefore, there is a compromise to be found between these two quantities.

  18. Using System Dynamics to Define, Study, and Implement Smart Control Strategies on the Electric Power Grid

    SciTech Connect

    Lyle G. Roybal; Robert F Jeffers

    2013-07-01

    The United States electric power grid is the most complex and expansive control system in the world. Local generation control occurs at individual units based on response time and unit economics, larger regional control coordinates unit response to error conditions, and high level large-area regional control is ultimately administered by a network of humans guided by economic and resiliency related factors. Under normal operating conditions, the grid is a relatively slow moving entity that exhibits high inertia to outside stimuli, and behaves along repeatable diurnal and seasonal patterns. However, that paradigm is quickly changing because of the increasing implementation of renewable generation sources. Renewable generators by nature cannot be tightly controlled or scheduled. They appear like a negative load to the system with all of the variability associated with load on a larger scale. Also, grid-reactive loads (i.e. smart devices) can alter their consumption based on price or demand rules adding more variability to system behavior. This paper demonstrates how a systems dynamic modeling approach capable of operating over multiple time scales, can provide valuable insight into developing new “smart-grid” control strategies and devices needed to accommodate renewable generation and regulate the frequency of the grid.

  19. Fiber optic sensors for monitoring sodium circuits and power grid cables

    SciTech Connect

    Kasinathan, M.; Sosamma, S.; Pandian, C.; Vijayakumar, V.; Chandramouli, S.; Nashine, B. K.; Rao, C. B.; Murali, N.; Rajan, K. K.; Jayakumar, T.

    2011-07-01

    At Kalpakkam, India, a programme on development of Raman Distributed Temperature sensor (RDTS) for Fast Breeder Reactors (FBR) application is undertaken. Leak detection in sodium circuits of FBR is critical for the safety and performance of the reactors. It is demonstrated that RDTS can be usefully employed in monitoring sodium circuits and in tracking the percolating sodium in case of any leak. Aluminum Conductor Steel Reinforced (ACSR) cable is commonly used as overhead power transmission cable in power grid. A second application demonstrates the suitability of using RDTS to monitor this transmission cable for any defect. (authors)

  20. Single stage AC-DC converter for Galfenol-based micro-power energy harvesters

    NASA Astrophysics Data System (ADS)

    Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

    2014-06-01

    Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.

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

    PubMed

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

    2015-05-01

    Hydropeaking operations can severely degrade ecosystems. As variable renewable sources (e.g. wind power) are integrated into a power grid, fluctuations in the generation-demand balance are expected to increase. In this context, compensating technologies, notably hydropower reservoir plants, could operate in a stronger peaking scheme. This issue calls for an integrated modeling of the entire power system, including not only hydropower reservoirs, but also all other plants. A novel methodology to study the link between the short-term variability of renewable energies and the subdaily hydrologic alteration, due to hydropower reservoir operations is presented. Grid operations under selected wind power portfolios are simulated using a short-term hydro-thermal coordination tool. The resulting turbined flows by relevant reservoir plants are then compared in terms of the Richard-Baker flashiness index to both the baseline and the natural flow regime. Those are then analyzed in order to: i) detect if there is a significant change in the degree of subdaily hydrologic alteration (SDHA) due to a larger wind penetration, and ii) identify which rivers are most affected. The proposed scheme is applied to Chile's Central Interconnect System (SIC) for scenarios up to 15% of wind energy penetration. Results show a major degree of SDHA under the baseline as compared to the natural regime. As wind power increases, so does the SDHA in two important rivers. This suggests a need for further ecological studies in those rivers, along with an analysis of operational constraints to limit the SDHA. PMID:25728917

  2. A High Performance Computing Network and System Simulator for the Power Grid: NGNS^2

    SciTech Connect

    Villa, Oreste; Tumeo, Antonino; Ciraci, Selim; Daily, Jeffrey A.; Fuller, Jason C.

    2012-11-11

    Designing and planing next generation power grid sys- tems composed of large power distribution networks, monitoring and control networks, autonomous generators and consumers of power requires advanced simulation infrastructures. The objective is to predict and analyze in time the behavior of networks of systems for unexpected events such as loss of connectivity, malicious attacks and power loss scenarios. This ultimately allows one to answer questions such as: “What could happen to the power grid if ...”. We want to be able to answer as many questions as possible in the shortest possible time for the largest possible systems. In this paper we present a new High Performance Computing (HPC) oriented simulation infrastructure named Next Generation Network and System Simulator (NGNS2 ). NGNS2 allows for the distribution of a single simulation among multiple computing elements by using MPI and OpenMP threads. NGNS2 provides extensive configuration, fault tolerant and load balancing capabilities needed to simulate large and dynamic systems for long periods of time. We show the preliminary results of the simulator running approximately two million simulated entities both on a 64-node commodity Infiniband cluster and a 48-core SMP workstation.

  3. Distributed Power Control Network and Green Building Test-Bed for Demand Response in Smart Grid

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Kei; Nguyen, Van Ky; Tao, Yu; Tran, Gia Khanh; Araki, Kiyomichi

    It is known that demand and supply power balancing is an essential method to operate power delivery system and prevent blackouts caused by power shortage. In this paper, we focus on the implementation of demand response strategy to save power during peak hours by using Smart Grid. It is obviously impractical with centralized power control network to realize the real-time control performance, where a single central controller measures the huge metering data and sends control command back to all customers. For that purpose, we propose a new architecture of hierarchical distributed power control network which is scalable regardless of the network size. The sub-controllers are introduced to partition the large system into smaller distributed clusters where low-latency local feedback power control loops are conducted to guarantee control stability. Furthermore, sub-controllers are stacked up in an hierarchical manner such that data are fed back layer-by-layer in the inbound while in the outbound control responses are decentralized in each local sub-controller for realizing the global objectives. Numerical simulations in a realistic scenario of up to 5000 consumers show the effectiveness of the proposed scheme to achieve a desired 10% peak power saving by using off-the-shelf wireless devices with IEEE802.15.4g standard. In addition, a small scale power control system for green building test-bed is implemented to demonstrate the potential use of the proposed scheme for power saving in real life.

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

    SciTech Connect

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

    2002-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Nguyen, Cuong Phuc

    2011-12-01

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

  6. Enhanced Short-Term Wind Power Forecasting and Value to Grid Operations: Preprint

    SciTech Connect

    Orwig, K.; Clark, C.; Cline, J.; Benjamin, S.; Wilczak, J.; Marquis, M.; Finley, C.; Stern, A.; Freedman, J.

    2012-09-01

    The current state of the art of wind power forecasting in the 0- to 6-hour time frame has levels of uncertainty that are adding increased costs and risk on the U.S. electrical grid. It is widely recognized within the electrical grid community that improvements to these forecasts could greatly reduce the costs and risks associated with integrating higher penetrations of wind energy. The U.S. Department of Energy has sponsored a research campaign in partnership with the National Oceanic and Atmospheric Administration (NOAA) and private industry to foster improvements in wind power forecasting. The research campaign involves a three-pronged approach: 1) a 1-year field measurement campaign within two regions; 2) enhancement of NOAA's experimental 3-km High-Resolution Rapid Refresh (HRRR) model by assimilating the data from the field campaign; and 3) evaluation of the economic and reliability benefits of improved forecasts to grid operators. This paper and presentation provides an overview of the regions selected, instrumentation deployed, data quality and control, assimilation of data into HRRR, and preliminary results of HRRR performance analysis.

  7. Power-grid Network Partitioning and Cluster Optimization with Applications to Florida and Texas

    NASA Astrophysics Data System (ADS)

    Rikvold, Per Arne; Abou Hamad, Ibrahim; Israels, Brett; Poroseva, Svetlana V.

    2012-02-01

    Cascading power-grid failures pose serious threats to lives and property, and it is desirable to contain them within a limited geographical area. One method to achieve this is Intelligent Intentional Islanding (I3): the purposeful partitioning of a grid into weakly connected ``islands'' of closely connected generators and loads. If such islands can be quickly isolated, the spread of faults can be limited. An additional constraint is that generating capacity and power demand within each island should be closely balanced to ensure self-sufficiency. I3 thus corresponds to constrained community detection in a network. After a matrix-based initial agglomeration of nearby loads and generators, we implement Monte Carlo simulated annealing to simultaneously optimize load-balance and internal connectivity of the resulting islands. The optimized network of islands is treated as a new network with the first-generation islands as the new nodes (``supergenerators'' and ``superloads''), and the same agglomeration and MC procedures are iteratively applied, reminiscent of real-space renormalization. Applications to the Floridian [1] and Texan high-voltage grids are demonstrated.[4pt] [1] I. Abou Hamad et al., Phys. Proc. 4, 125-129 (2010); Phys. Proc. 15, 2-6 (2011).

  8. Long-term operating characteristics of Japan's first in-grid HTS power cable

    NASA Astrophysics Data System (ADS)

    Nakano, Tetsutaro; Maruyama, Osamu; Honjo, Shoichi; Watanabe, Michihiko; Masuda, Takato; Hirose, Masayuki; Shimoda, Masahiro; Nakamura, Naoko; Yaguchi, Hiroharu; Machida, Akito

    2015-11-01

    Tokyo Electric Power Company, Sumitomo Electric Industries, Ltd and Mayekawa Mfg. Co., Ltd have jointly conducted the first in-grid demonstration test of a high-temperature superconducting (HTS) cable in Japan, from FY2007 to FY2013. The objective of this project is to evaluate the reliability, stability and other characteristics of the system. The cable structure used in this project is the type of three-in-one cable. As a coolant, sub-cooled liquid nitrogen flows through the gap between the corrugated cryostat and the three cable cores. This structure can realize compactness and reduce heat invasion compared with three single-core HTS cables housed in separate cryostats. The cooling system consists of six refrigerators, two circulation pumps and a reservoir tank. Each refrigerator has a cooling power of 1.0 kW at 77 K, 0.8 kW at 67 K. The number of operating refrigerators is controlled so that the coolant temperature at the cable inlet is kept to preset value. The HTS cable was connected to the live electricity grid from October 29, 2012 to December 25, 2013. In-grid operation continued for more than one year without any accidental interruption of operation or other operating issues. During this time, we studied the operating performance of the HTS cable in dependence on the sub-cooled LN2 temperature.

  9. A PWM quadrature-booster phase shifter for ac power transmission

    SciTech Connect

    Lopes, L.A.C.; Joos, G.; Ooi, B.T.

    1997-01-01

    The conventional structures used for phase shifters employ quadrature voltage injection controlled by means of on-load tap changers that require considerable maintenance. Line-commutated thyristor structures have been proposed to replace tap changers, but problems related to filter requirements or the number of switches have limited their utilization. This paper proposes a pulse width modulation (PWM) quadrature-booster phase shifter based on a force-commutated ac controller. It offers features such as fast dynamic response, continuous variation of the phase angle with low harmonic injection, and it requires a simple power structure and can be controlled by adjusting the duty cycle of the switches. The operating principles of the proposed phase shifter are analyzed and their feasibility is demonstrated through digital simulation and experimental implementation.

  10. Theory of ac loss in power transmission cables with second generation high temperature superconductor wires

    SciTech Connect

    Clem, J. R.; Malozemoff, A. P.

    2010-02-22

    While a considerable amount of work has been done in an effort to understand ac losses in power transmission cables made of first generation high temperature superconductor (HTS) wires, use of second generation (2G) HTS wires brings in some new considerations. The high critical current density of the HTS layer in 2G wires reduces the surface superconductor hysteretic losses, for which a new formula is derived. Instead, gap and polygonal losses, flux transfer losses in imbalanced two-layer cables and ferromagnetic losses for wires with NiW substrates constitute the principal contributions. A formula for the flux transfer losses is also derived with a paramagnetic approximation for the substrate. Current imbalance and losses associated with the magnetic substrate can be minimized by orienting the substrates of the inner winding inward and the outer winding outward.

  11. Resonant AC power system proof-of-concept test program, volume 2, appendix 1

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This report contains two volumes. The main text (Volume 1) summarizes the tests results and gives a detailed discussion of the response of three early, first generation configurations of ac power system IRAD breadboards to the contracted tests imposed on them. It explains photographs, measurements, and data calculations, as well as any observed anomalies or lessons learned. This volume (No 2, Appendix 1, Test Results and Data), published under separate cover, includes all of the data taken on the 1.0 kW single-phase; 5.0 kW three-phase; and 25.0-kW three-phase system breadboards. The format of this data is raw, i.e., it is a direct copy of the data sheets for the test data notebook.

  12. Transport ac loss of elliptical thin strips with a power-law E(J) relation

    NASA Astrophysics Data System (ADS)

    Jia, Chen-Xi; Chen, Du-Xing; Li, Shuo; Fang, Jin

    2015-10-01

    The transport ac loss Q of an elliptical thin strip of critical current I c with a power-law relation E\\propto {J}n is accurately computed as a function of current amplitude I m and frequency f. The resulting Q({I}m) is normalized to q({i}m) following the Norris critical-state formula, and converted to {q}*({i}m*) at a critical frequency f c based on a transport scaling law. Having a set of {q}*({i}m*) at several values of n as a base, a general expression of {q}*({i}m*,n) is obtained, which can be used to easily calculate q({i}m) for any practical purposes.

  13. Voltage source ac-to-dc converters for high-power transmitters

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1990-01-01

    This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.

  14. High power dc/dc and dc/ac electrical power conversion techniques developed

    NASA Technical Reports Server (NTRS)

    Berryman, G.; White, W. T.

    1967-01-01

    Small magnetic amplifiers pass square waves through transformers and provide regulation by varying the pulse width on the secondary of the output power transformers. This pulse duration modulation is provided by a control rectifier technique or a phase-shift technique.

  15. A random growth model for power grids and other spatially embedded infrastructure networks

    NASA Astrophysics Data System (ADS)

    Schultz, Paul; Heitzig, Jobst; Kurths, Jürgen

    2014-09-01

    We propose a model to create synthetic networks that may also serve as a narrative of a certain kind of infrastructure network evolution. It consists of an initialization phase with the network extending tree-like for minimum cost and a growth phase with an attachment rule giving a trade-off between cost-optimization and redundancy. Furthermore, we implement the feature of some lines being split during the grid's evolution. We show that the resulting degree distribution has an exponential tail and may show a maximum at degree two, suitable to observations of real-world power grid networks. In particular, the mean degree and the slope of the exponential decay can be controlled in partial independence. To verify to which extent the degree distribution is described by our analytic form, we conduct statistical tests, showing that the hypothesis of an exponential tail is well-accepted for our model data.

  16. A random growth model for power grids and other spatially embedded infrastructure networks

    NASA Astrophysics Data System (ADS)

    Schultz, Paul; Heitzig, Jobst; Kurths, Jürgen

    2014-10-01

    We propose a model to create synthetic networks that may also serve as a narrative of a certain kind of infrastructure network evolution. It consists of an initialization phase with the network extending tree-like for minimum cost and a growth phase with an attachment rule giving a trade-off between cost-optimization and redundancy. Furthermore, we implement the feature of some lines being split during the grid's evolution. We show that the resulting degree distribution has an exponential tail and may show a maximum at degree two, suitable to observations of real-world power grid networks. In particular, the mean degree and the slope of the exponential decay can be controlled in partial independence. To verify to which extent the degree distribution is described by our analytic form, we conduct statistical tests, showing that the hypothesis of an exponential tail is well-accepted for our model data.

  17. Development of a single-phase harmonic power flow program to study the 20 kHz AC power system for large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan; Kankam, M. David

    1991-01-01

    The development of software is described to aid in design and analysis of AC power systems for large spacecraft. The algorithm is an important version of harmonic power flow program, HARMFLO, used for the study of AC power quality. The new program is applicable to three-phase systems typified by terrestrial power systems, and single-phase systems characteristic of space power systems. The modified HARMFLO accommodates system operating frequencies ranging from terrestrial 60 Hz to and beyond aerospace 20 kHz, and can handle both source and load-end harmonic distortions. Comparison of simulation and test results of a representative spacecraft power system shows a satisfactory correlation. Recommendations are made for the direction of future improvements to the software, to enhance its usefulness to power system designer and analysts.

  18. Optimal Dispatch of Unreliable Electric Grid-Connected Diesel Generator-Battery Power Systems

    NASA Astrophysics Data System (ADS)

    Xu, D.; Kang, L.

    2015-06-01

    Diesel generator (DG)-battery power systems are often adopted by telecom operators, especially in semi-urban and rural areas of developing countries. Unreliable electric grids (UEG), which have frequent and lengthy outages, are peculiar to these regions. DG-UEG-battery power system is an important kind of hybrid power system. System dispatch is one of the key factors to hybrid power system integration. In this paper, the system dispatch of a DG-UEG-lead acid battery power system is studied with the UEG of relatively ample electricity in Central African Republic (CAR) and UEG of poor electricity in Congo Republic (CR). The mathematical models of the power system and the UEG are studied for completing the system operation simulation program. The net present cost (NPC) of the power system is the main evaluation index. The state of charge (SOC) set points and battery bank charging current are the optimization variables. For the UEG in CAR, the optimal dispatch solution is SOC start and stop points 0.4 and 0.5 that belong to the Micro-Cycling strategy and charging current 0.1 C. For the UEG in CR, the optimal dispatch solution is of 0.1 and 0.8 that belongs to the Cycle-Charging strategy and 0.1 C. Charging current 0.1 C is suitable for both grid scenarios compared to 0.2 C. It makes the dispatch strategy design easier in commercial practices that there are a few very good candidate dispatch solutions with system NPC values close to that of the optimal solution for both UEG scenarios in CAR and CR.

  19. Power Smoothing and MPPT for Grid-connected Wind Power Generation with Doubly Fed Induction Generator

    NASA Astrophysics Data System (ADS)

    Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

    Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation, and variable speed control and power factor control are executed for high efficiently for wind energy capture and high quality for power system voltage. In variable speed control, a wind speed or a generator speed is used for maximum power point tracking. However, performances of a wind generation power fluctuation due to wind speed variation have not yet investigated for those controls. The authors discuss power smoothing by those controls for the DFIG inter-connected to 6.6kV distribution line. The performances are verified using power system simulation software PSCAD/EMTDC for actual wind speed data and are examined from an approximate equation of wind generation power fluctuation for wind speed variation.

  20. Integration of permanent magnet synchronous generator wind turbines into power grid

    NASA Astrophysics Data System (ADS)

    Abedini, Asghar

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

  1. Experience in Developing a Single-Phase Two Winding 5 kW Self-excited Induction Generator for Off-Grid Renewable Energy Based Power Generation

    NASA Astrophysics Data System (ADS)

    Murthy, S. S.; Singh, Bhim; Sandeep, Vuddanti

    2016-06-01

    This paper deals with the design and development of a novel single-phase two winding self-excited squirrel cage induction generator (SEIG) for off-grid renewable energy based power generation. The principles underlying the design process and experience with SPEED design tool are described to design a 5 kW, 50 Hz, 230 V, 4 pole single phase AC generator. All possible configurations to reduce harmonic components of induced e.m.f. are attempted for desired performance and to get an optimum design keeping in view the manufacturing constraints. The development of a prototype based on this design has been completed with the help of an industry. Typical test results on the prototype are presented to demonstrate its performance. Computed results are obtained with a design based computational procedure for performance analysis and a critical comparison is made with test results.

  2. A reliable data delivery mechanism for grid power quality using neural networks in wireless sensor networks.

    PubMed

    Lim, Yujin; Kim, Hak-Man; Kang, Sanggil

    2010-01-01

    Power grids deal with the business of generation, transmission, and distribution of electric power. Current systems monitor basic electrical quantities such as voltage and current from major pole transformers using their temperature. We improve the current systems in order to gather and deliver the information of power qualities such as harmonics, voltage sags, and voltage swells. In the system, data delivery is not guaranteed for the case that a node is lost or the network is congested, because the system has in-line and multi-hop architecture. In this paper, we propose a reliable data delivery mechanism by modeling an optimal data delivery function by employing the neural network concept. PMID:22163411

  3. A Reliable Data Delivery Mechanism for Grid Power Quality Using Neural Networks in Wireless Sensor Networks

    PubMed Central

    Lim, Yujin; Kim, Hak-Man; Kang, Sanggil

    2010-01-01

    Power grids deal with the business of generation, transmission, and distribution of electric power. Current systems monitor basic electrical quantities such as voltage and current from major pole transformers using their temperature. We improve the current systems in order to gather and deliver the information of power qualities such as harmonics, voltage sags, and voltage swells. In the system, data delivery is not guaranteed for the case that a node is lost or the network is congested, because the system has in-line and multi-hop architecture. In this paper, we propose a reliable data delivery mechanism by modeling an optimal data delivery function by employing the neural network concept. PMID:22163411

  4. A grid-connected photovoltaic power conversion system with single-phase multilevel inverter

    SciTech Connect

    Beser, Ersoy; Arifoglu, Birol; Camur, Sabri; Beser, Esra Kandemir

    2010-12-15

    This paper presents a grid-connected photovoltaic (PV) power conversion system based on a single-phase multilevel inverter. The proposed system fundamentally consists of PV arrays and a single-phase multilevel inverter structure. First, configuration and structural parts of the PV assisted inverter system are introduced in detail. To produce reference output voltage waves, a simple switching strategy based on calculating switching angles is improved. By calculated switching angles, the reference signal is produced as a multilevel shaped output voltage wave. The control algorithm and operational principles of the proposed system are explained. Operating PV arrays in the same load condition is a considerable point; therefore a simulation study is performed to arrange the PV arrays. After determining the number and connection types of the PV arrays, the system is configured through the arrangement of the PV arrays. The validity of the proposed system is verified through simulations and experimental study. The results demonstrate that the system can achieve lower total harmonic distortion (THD) on the output voltage and load current, and it is capable of operating synchronous and transferring power values having different characteristic to the grid. Hence, it is suitable to use the proposed configuration as a PV power conversion system in various applications. (author)

  5. A Power Grid Optimization Algorithm by Observing Timing Error Risk by IR Drop

    NASA Astrophysics Data System (ADS)

    Kawakami, Yoshiyuki; Terao, Makoto; Fukui, Masahiro; Tsukiyama, Shuji

    With the advent of the deep submicron age, circuit performance is strongly impacted by process variations and the influence on the circuit delay to the power-supply voltage increases more and more due to CMOS feature size shrinkage. Power grid optimization which considers the timing error risk caused by the variations and IR drop becomes very important for stable and hi-speed operation of system-on-chip. Conventionally, a lot of power grid optimization algorithms have been proposed, and most of them use IR drop as their object functions. However, the IR drop is an indirect metric and we suspect that it is vague metric for the real goal of LSI design. In this paper, first, we propose an approach which uses the “timing error risk caused by IR drop” as a direct objective function. Second, the critical path map is introduced to express the existence of critical paths distributed in the entire chip. The timing error risk is decreased by using the critical path map and the new objective function. Some experimental results show the effectiveness.

  6. Mathematical model of an off-grid hybrid solar and wind power generating system

    NASA Astrophysics Data System (ADS)

    Blasone, M.; Dell'Anno, F.; De Luca, R.; Torre, G.

    2014-12-01

    The dynamics of an off-grid power generating system, coupled to a storage unit and to household appliances, is described by means of an analytic hydrodynamic analog. Following this analogy, by noticing that the effux rate from a leaking bucket is described, in terms of the liquid content, by Torricelli's formula, we denote as "Torricelli's smart consumer" a user being able to calibrate its energy consumption rate with respect to the energy level in the storage unit as if the hydrodynamic model would strictly apply. Simple solutions to the nonlinear dynamic problem associated to this type of smart consumer are found and generalization to other types of smart consumers are sought.

  7. Connections beyond the margins of the power grid Information technology and the evolution of off-grid solar electricity in the developing world

    NASA Astrophysics Data System (ADS)

    Alstone, Peter Michael

    This work explores the intersections of information technology and off-grid electricity deployment in the developing world with focus on a key instance: the emergence of pay-as-you-go (PAYG) solar household-scale energy systems. It is grounded in detailed field study by my research team in Kenya between 2013-2014 that included primary data collection across the solar supply chain from global businesses through national and local distribution and to the end-users. We supplement the information with business process and national survey data to develop a detailed view of the markets, technology systems, and individuals who interact within those frameworks. The findings are presented in this dissertation as a series of four chapters with introductory, bridging, and synthesis material between them. The first chapter, Decentralized Energy Systems for Clean Electricity Access, presents a global view of the emerging off-grid power sector. Long-run trends in technology create "a unique moment in history" for closing the gap between global population and access to electricity, which has stubbornly held at 1-2 billion people without power since the initiation of the electric utility business model in the late 1800's. We show the potential for widespread near-term adoption of off-grid solar, which could lead to ten times less inequality in access and also ten times lower household-level climate impacts. Decentralized power systems that replace fuel-based incumbent lighting can advance the causes of climate stabilization, economic and social freedom and human health. Chapters two and three are focused on market and institutional dynamics present circa 2014 in for off-grid solar with a focus on the Kenya market. Chapter 2, "Off-grid Power and Connectivity", presents our findings related to the widespread influence of information technology across the supply chain for solar and in PAYG approaches. Using digital financing and embedded payment verification technology, PAYG

  8. Study on the SMES Application Solutions for Smart Grid

    NASA Astrophysics Data System (ADS)

    Jin, Jian Xun; Chen, Xiao Yuan

    This paper proposes the application solutions of the superconducting magnetic energy storage (SMES) technology for using in future smart grids. The compensation power arrangements in hybrid energy storage systems (ESSs) using small-scale SMESs have been discussed. The particle swarm optimization (PSO) algorithm is proposed to solve the Pareto optimal solution set in distributed SMES (D-SMES) solution. The practical application schemes for micro grid, flexible AC transmission and distribution systems, and the whole power system including the power generation side, power transmission side, power distribution side and power consumer side have then been proposed and discussed.

  9. Assessing achievement, affiliation, and power motives all at once: the Multi-Motive Grid (MMG).

    PubMed

    Sokolowski, K; Schmalt, H D; Langens, T A; Puca, R M

    2000-02-01

    In this article, we introduce the Multi-Motive Grid (MMG), a new diagnostic tool to measure motives with respect to their hope and fear components. The MMG combines features of the Thematic Apperception Test (TAT) with features of self-report questionnaires. Similar to the TAT, a set of 14 pictures representing a balanced set of achievement-arousing, affiliation-arousing, and power-arousing situations is presented together with a set of statements representing important motivational states. Six motive scores can be calculated: hope of success (HS) and fear of failure (FF) for the achievement motive, hope of affiliation (HA) and fear of rejection (FR) for the affiliation motive, and hope of power (HP) and fear of power (FP) for the power motive. Results of factor analyses suggest a 3-factor solution, with a general fear factor (FF, FR, FP), a factor combining the hope components of achievement and power (HS and HP), and a third factor representing HA, but the 6 a priori factors also reflect a sound structural model. Reliability data show that the internal consistency and retest reliability of the MMG scales satisfy traditional standards. External validity of the MMG has been established in all 3 motive domains. Three separate studies document that (a) individuals high in resultant achievement motivation perform better and report more flow experience, (b) individuals high in resultant power motivation profit more from a leadership training program, and (c) individuals high in resultant affiliation motivation recollect more highly memorable affiliative themes. PMID:10779937

  10. Real power regulation for the utility power grid via responsive loads

    DOEpatents

    McIntyre, Timothy J [Knoxville, TN; Kirby, Brendan J [Knoxville, TN; Kisner, Roger A

    2009-05-19

    A system for dynamically managing an electrical power system that determines measures of performance and control criteria for the electric power system, collects at least one automatic generation control (AGC) input parameter to at least one AGC module and at least one automatic load control (ALC) input parameter to at least one ALC module, calculates AGC control signals and loads as resources (LAR) control signals in response to said measures of performance and control criteria, propagates AGC control signals to power generating units in response to control logic in AGC modules, and propagates LAR control signals to at least one LAR in response to control logic in ALC modules.

  11. Laser ray tracing and power deposition on an unstructured three-dimensional grid

    PubMed

    Kaiser

    2000-01-01

    A scheme is presented for laser beam evolution and power deposition on three-dimensional unstructured grids composed of hexahedra, prisms, pyramids, and tetrahedra. The geometrical-optics approximation to the electromagnetic wave equation is used to follow propagation of a collection of discrete rays used to represent the beam(s). Ray trajectory equations are integrated using a method that is second order in time, exact for a constant electron-density gradient, and capable of dealing with density discontinuities that arise in certain hydrodynamics formulations. Power deposition by inverse-bremsstrahlung is modeled with a scheme based on Gaussian quadrature to accommodate a deposition rate whose spatial variation is highly nonuniform. Comparisons with analytic results are given for a density ramp in three dimensions, and a "quadratic-well" density trough in two dimensions. PMID:11046339

  12. Distributing Power Grid State Estimation on HPC Clusters A System Architecture Prototype

    SciTech Connect

    Liu, Yan; Jiang, Wei; Jin, Shuangshuang; Rice, Mark J.; Chen, Yousu

    2012-08-20

    The future power grid is expected to further expand with highly distributed energy sources and smart loads. The increased size and complexity lead to increased burden on existing computational resources in energy control centers. Thus the need to perform real-time assessment on such systems entails efficient means to distribute centralized functions such as state estimation in the power system. In this paper, we present our early prototype of a system architecture that connects distributed state estimators individually running parallel programs to solve non-linear estimation procedure. The prototype consists of a middleware and data processing toolkits that allows data exchange in the distributed state estimation. We build a test case based on the IEEE 118 bus system and partition the state estimation of the whole system model to available HPC clusters. The measurement from the testbed demonstrates the low overhead of our solution.

  13. A Latency-Tolerant Partitioner for Distributed Computing on the Information Power Grid

    NASA Technical Reports Server (NTRS)

    Das, Sajal K.; Harvey, Daniel J.; Biwas, Rupak; Kwak, Dochan (Technical Monitor)

    2001-01-01

    NASA's Information Power Grid (IPG) is an infrastructure designed to harness the power of graphically distributed computers, databases, and human expertise, in order to solve large-scale realistic computational problems. This type of a meta-computing environment is necessary to present a unified virtual machine to application developers that hides the intricacies of a highly heterogeneous environment and yet maintains adequate security. In this paper, we present a novel partitioning scheme. called MinEX, that dynamically balances processor workloads while minimizing data movement and runtime communication, for applications that are executed in a parallel distributed fashion on the IPG. We also analyze the conditions that are required for the IPG to be an effective tool for such distributed computations. Our results show that MinEX is a viable load balancer provided the nodes of the IPG are connected by a high-speed asynchronous interconnection network.

  14. Nearly Unity Power-Factor of the Modular Three-Phase AC to DC Converter with Minimized DC Bus Capacitor

    NASA Astrophysics Data System (ADS)

    Chunkag, Viboon; Kamnarn, Uthen

    The analysis and design of nearly unity power-factor and fast dynamic response of the modular three-phase ac to dc converter using three single-phase isolated SEPIC rectifier modules with minimized dc bus capacitor is discussed, based on power balance control technique. The averaged small-signal technique is used to obtain the inductor current compensator, thus resulting in the output impedance and audio susceptibility become zero, that is, the output voltage of the converter presented in this paper is independent of the variations of the dc load current and the utility voltage. The proposed system significantly improves the dynamic response of the converter to load steps with minimized dc bus capacitor for Distributed Power System (DPS). A 600W prototype modular three-phase ac to dc converter comprising three 200W single-phase SEPIC rectifier modules with the proposed control scheme has been designed and implemented. The proposed system is confirmed by experimental implementation.

  15. A High Performance Computing Platform for Performing High-Volume Studies With Windows-based Power Grid Tools

    SciTech Connect

    Chen, Yousu; Huang, Zhenyu

    2014-08-31

    Serial Windows-based programs are widely used in power utilities. For applications that require high volume simulations, the single CPU runtime can be on the order of days or weeks. The lengthy runtime, along with the availability of low cost hardware, is leading utilities to seriously consider High Performance Computing (HPC) techniques. However, the vast majority of the HPC computers are still Linux-based and many HPC applications have been custom developed external to the core simulation engine without consideration for ease of use. This has created a technical gap for applying HPC-based tools to today’s power grid studies. To fill this gap and accelerate the acceptance and adoption of HPC for power grid applications, this paper presents a prototype of generic HPC platform for running Windows-based power grid programs on Linux-based HPC environment. The preliminary results show that the runtime can be reduced from weeks to hours to improve work efficiency.

  16. The Feasibility of Moving PMU Data in the Future Power Grid

    SciTech Connect

    Gibson, Tara D.; Kulkarni, Anand V.; Kleese van Dam, Kerstin; Critchlow, Terence J.

    2011-09-07

    The power grid is a complex network connecting electricity providers with their consumers. With an increasing consumer base requiring more resources and the requirement to integrate significant renewable sources, maintaining the network requires new and innovative management solutions. To manage this complexity and provide precise, real-time views of the grid, Phasor Measurement Units (PMUs) are undergoing widespread deployment. These units provide measurements as often as 60 times per second, with an accurate time identifier attached to each reading, enabling real-time monitoring of the network. However, this new capability generates much more data than the current infrastructure is designed to handle. With the expectation that there will eventually be tens of thousands of PMUs monitoring the transmission lines, the power community is looking towards accumulating multiple terabytes of data per day - several orders of magnitude beyond current data acquisition rates. This has led to questions being raised in the power community about whether or not a significant research effort is required to effectively transfer the volume of information generated by these new data streams. This paper answers that question by comparing a worst-case data generation scenario with several alternative networking protocols and historical trends in protocol advancement. Based on this analysis we are able to conclude that transferring the information between the PMUs and the resulting data repositories is feasible. We recognize that there are issues beyond transferring the data that need to be addressed such as effective access to historical data, data transfer latency, cyber security, and data analysis. There is also an extensive engineering trade-off that the power companies will need to make to decide the best mix of networking protocols for their particular PMU deployments, since that requires significant assumptions about proprietary information including deployment cost, deployment

  17. Technical evaluation of the station and instrument ground grid systems at the Davis Besse Nuclear Power Station, Unit 1

    SciTech Connect

    Selan, J.C.

    1981-06-29

    This report documents the technical evaluation of the station and instrument ground grid systems at the Davis Besse Nuclear Power Station, Unit 1. The evaluation is to determine that there are no inadvertent ties between the instrument and station ground grid systems, that any identified inadvertent ties are corrected, and to assure that the installation meets design criteria. The information submitted by the licensee indicates that there are no inadvertent ties between the station and instrument ground grid systems and that the installation meets design criteria.

  18. Implementation of high concentration photovoltaic grid connected power plant for training, research, innovation and solar electricity production

    NASA Astrophysics Data System (ADS)

    Barhdadi, A.; Benazzouz, A.; Fabrizio, B.; Verdilio, D.

    2015-04-01

    In this paper, performance monitoring program is applied to a grid-connected high concentration photovoltaic power plant in order to identify any operational problem and to make sure of its optimal and continuous power generation working conditions. A preventive maintenance plan was also established and proposed for the whole system.

  19. A Measurement and Power Line Communication System Design for Renewable Smart Grids

    NASA Astrophysics Data System (ADS)

    Kabalci, E.; Kabalci, Y.

    2013-10-01

    The data communication over the electric power lines can be managed easily and economically since the grid connections are already spread around all over the world. This paper investigates the applicability of Power Line Communication (PLC) in an energy generation system that is based on photovoltaic (PV) panels with the modeling study in Matlab/Simulink. The Simulink model covers the designed PV panels, boost converter with Perturb and Observe (P&O) control algorithm, full bridge inverter, and the binary phase shift keying (BPSK) modem that is utilized to transfer the measured data over the power lines. This study proposes a novel method to use the electrical power lines not only for carrying the line voltage but also to transmit the measurements of the renewable energy generation plants. Hence, it is aimed at minimizing the additional monitoring costs such as SCADA, Ethernet-based or GSM based systems by using the proposed technique. Although this study is performed with solar power plants, the proposed model can be applied to other renewable generation systems. Consequently, the usage of the proposed technique instead of SCADA or Ethernet-based systems eliminates additional monitoring costs.

  20. PLL Based Energy Efficient PV System with Fuzzy Logic Based Power Tracker for Smart Grid Applications.

    PubMed

    Rohini, G; Jamuna, V

    2016-01-01

    This work aims at improving the dynamic performance of the available photovoltaic (PV) system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results. PMID:27294189

  1. PLL Based Energy Efficient PV System with Fuzzy Logic Based Power Tracker for Smart Grid Applications

    PubMed Central

    Rohini, G.; Jamuna, V.

    2016-01-01

    This work aims at improving the dynamic performance of the available photovoltaic (PV) system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results. PMID:27294189

  2. AC electrokinetic drug delivery in dentistry using an interdigitated electrode assembly powered by inductive coupling.

    PubMed

    Ivanoff, Chris S; Wu, Jie Jayne; Mirzajani, Hadi; Cheng, Cheng; Yuan, Quan; Kevorkyan, Stepan; Gaydarova, Radostina; Tomlekova, Desislava

    2016-10-01

    AC electrokinetics (ACEK) has been shown to deliver certain drugs into human teeth more effectively than diffusion. However, using electrical wires to power intraoral ACEK devices poses risks to patients. The study demonstrates a novel interdigitated electrode arrays (IDE) assembly powered by inductive coupling to induce ACEK effects at appropriate frequencies to motivate drugs wirelessly. A signal generator produces the modulating signal, which multiplies with the carrier signal to produce the amplitude modulated (AM) signal. The AM signal goes through the inductive link to appear on the secondary coil, then rectified and filtered to dispose of its carrier signal, and the positive half of the modulating signal appears on the load. After characterizing the device, the device is validated under light microscopy by motivating carboxylate-modified microspheres, tetracycline, acetaminophen, benzocaine, lidocaine and carbamide peroxide particles with induced ACEK effects. The assembly is finally tested in a common dental bleaching application. After applying 35 % carbamide peroxide to human teeth topically or with the IDE at 1200 Hz, 5 Vpp for 20 min, spectrophotometric analysis showed that compared to diffusion, the IDE enhanced whitening in specular optic and specular optic excluded modes by 215 % and 194 % respectively. Carbamide peroxide absorbance by the ACEK group was two times greater than diffusion as measured by colorimetric oxidation-reduction and UV-Vis spectroscopy at 550 nm. The device motivates drugs of variable molecular weight and structure wirelessly. Wireless transport of drugs to intraoral targets under ACEK effects may potentially improve the efficacy and safety of drug delivery in dentistry. PMID:27565821

  3. Engaging in cross-border power exchange and trade via the Arab Gulf states power grid

    SciTech Connect

    Fraser, Hamish; Al-Asaad, Hassan K.

    2008-12-15

    When construction is complete in 2010, an interconnector established among the Gulf states will enhance their electricity infrastructure while increasing reliability and security of power supply. The interconnector will also foster exchanges of energy and facilitate cross-border trade. (author)

  4. Pulse doubling in zigzag-connected autotransformer-based 12-pulse ac-dc converter for power quality improvement

    NASA Astrophysics Data System (ADS)

    Abdollahi, Rohollah

    2012-12-01

    This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMDs) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse acdc converters each of them consisting of three-phase diode bridge rectifiers. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.

  5. Evolutionary programming-based methodology for economical output power from PEM fuel cell for micro-grid application

    NASA Astrophysics Data System (ADS)

    El-Sharkh, M. Y.; Rahman, A.; Alam, M. S.

    This paper presents a methodology for finding the optimal output power from a PEM fuel cell power plant (FCPP). The FCPP is used to supply power to a small micro-grid community. The technique used is based on evolutionary programming (EP) to find a near-optimal solution of the problem. The method incorporates the Hill-Climbing technique (HCT) to maintain feasibility during the solution process. An economic model of the FCPP is used. The model considers the production cost of energy and the possibility of selling and buying electrical energy from the local grid. In addition, the model takes into account the thermal energy output from the FCPP and the thermal energy requirement for the micro-grid community. The results obtained are compared against a solution based on genetic algorithms. Results are encouraging and indicate viability of the proposed technique.

  6. Investigation of a family of power conditioners integrated into a utility grid: final report Category I

    SciTech Connect

    Wood, P.; Putkovich, R.P.

    1981-07-01

    A study was conducted of the requirements for and technologies applicable to power conditioning equipment in residential solar photovoltaic systems. A survey of companies known or thought to manufacture power conditioning equipment was conducted to asses the technology. Technical issues regarding ac and dc interface requirements were studied. A baseline design was selected to be a good example of existing technology which would not need significant development effort for its implementation. Alternative technologies are evaluated to determine which meet the baseline specification, and their costs and losses are evaluated. Areas in which cost improvements can be obtained are studied, and the three best candidate technologies--the current-sourced converter, the HF front end converter, and the programmed wave converter--are compared. It is concluded that the designs investigated will meet, or with slight improvement could meet, short term efficiency goals. Long term efficiency goals could be met if an isolation transformer were not required in the power conditioning equipment. None of the technologies studied can meet cost goals unless further improvements are possible. (LEW)

  7. Establishing the Geomagnetic Disturbance Benchmark Event for Evaluation of the Space Weather Hazard on Power Grids

    NASA Astrophysics Data System (ADS)

    Pulkkinen, A. A.; Bernabeu, E.; Eichner, J.

    2014-12-01

    The awareness about potential major impact geomagnetically induced currents (GIC) can have on the North American high-voltage power transmission system has prompted Federal Energy Regulatory Commission (FERC) to launch a geomagnetic disturbances (GMD) standards drafting process. The goals of the GMD standards are to quantify and mitigate the GMD hazard on the North American grid. North American Electric Reliability Corporation's (NERC) is coordinating the standards drafting process that is now entering Phase II involving quantification of the impact GIC can have on individual parts of the North American grid. As a part of the Phase II GMD standards drafting process, substantial effort has been made for generating benchmark GMD scenarios. These scenarios that quantify extreme geoelectric field magnitudes and temporal waveforms of the field fluctuations are the foundation for subsequent engineering and impacts analyses. The engineering analyses will include the transmission system voltage stability and transformer heating assessments. The work on the GMD scenarios has been a major collaboration between a number of international entities involved in GMD research and transmission system operations. We will discuss in this paper the key elements of the benchmark GMD generation process and show the latest results from our work on the topic.

  8. Thread Group Multithreading: Accelerating the Computation of an Agent-Based Power System Modeling and Simulation Tool -- C GridLAB-D

    SciTech Connect

    Jin, Shuangshuang; Chassin, David P.

    2014-01-06

    GridLAB-DTM is an open source next generation agent-based smart-grid simulator that provides unprecedented capability to model the performance of smart grid technologies. Over the past few years, GridLAB-D has been used to conduct important analyses of smart grid concepts, but it is still quite limited by its computational performance. In order to break through the performance bottleneck to meet the need for large scale power grid simulations, we develop a thread group mechanism to implement highly granular multithreaded computation in GridLAB-D. We achieve close to linear speedups on multithreading version compared against the single-thread version of the same code running on general purpose multi-core commodity for a benchmark simple house model. The performance of the multithreading code shows favorable scalability properties and resource utilization, and much shorter execution time for large-scale power grid simulations.

  9. Challenges and opportunities of power systems from smart homes to super-grids.

    PubMed

    Kuhn, Philipp; Huber, Matthias; Dorfner, Johannes; Hamacher, Thomas

    2016-01-01

    The world's power systems are facing a structural change including liberalization of markets and integration of renewable energy sources. This paper describes the challenges that lie ahead in this process and points out avenues for overcoming different problems at different scopes, ranging from individual homes to international super-grids. We apply energy system models at those different scopes and find a trade-off between technical and social complexity. Small-scale systems would require technological breakthroughs, especially for storage, but individual agents can and do already start to build and operate such systems. In contrast, large-scale systems could potentially be more efficient from a techno-economic point of view. However, new political frameworks are required that enable long-term cooperation among sovereign entities through mutual trust. Which scope first achieves its breakthrough is not clear yet. PMID:26667060

  10. Large-Scale Distributed Computational Fluid Dynamics on the Information Power Grid Using Globus

    NASA Technical Reports Server (NTRS)

    Barnard, Stephen; Biswas, Rupak; Saini, Subhash; VanderWijngaart, Robertus; Yarrow, Maurice; Zechtzer, Lou; Foster, Ian; Larsson, Olle

    1999-01-01

    This paper describes an experiment in which a large-scale scientific application development for tightly-coupled parallel machines is adapted to the distributed execution environment of the Information Power Grid (IPG). A brief overview of the IPG and a description of the computational fluid dynamics (CFD) algorithm are given. The Globus metacomputing toolkit is used as the enabling device for the geographically-distributed computation. Modifications related to latency hiding and Load balancing were required for an efficient implementation of the CFD application in the IPG environment. Performance results on a pair of SGI Origin 2000 machines indicate that real scientific applications can be effectively implemented on the IPG; however, a significant amount of continued effort is required to make such an environment useful and accessible to scientists and engineers.

  11. System and Battery Charge Control for PV-Powered AC Lighting Systems

    SciTech Connect

    Kern, G.

    1999-04-01

    This report reviews a number of issues specific to stand-alone AC lighting systems. A review of AC lighting technology is presented, which discusses the advantages and disadvantages of various lamps. The best lamps for small lighting systems are compact fluorescent. The best lamps for intermediate-size systems are high- or low-pressure sodium. Specifications for battery charging and load control are provided with the goal of achieving lamp lifetimes on the order of 16,000 to 24,000 hours and battery lifetimes of 4 to 5 years. A rough estimate of the potential domestic and global markets for stand-alone AC lighting systems is presented. DC current injection tests were performed on high-pressure sodium lamps and the test results are presented. Finally, a prototype system was designed and a prototype system controller (with battery charger and DC/AC inverter) was developed and built.

  12. Alpha Power Increase After Transcranial Alternating Current Stimulation at Alpha Frequency (α-tACS) Reflects Plastic Changes Rather Than Entrainment

    PubMed Central

    Vossen, Alexandra; Gross, Joachim; Thut, Gregor

    2015-01-01

    Background Periodic stimulation of occipital areas using transcranial alternating current stimulation (tACS) at alpha (α) frequency (8–12 Hz) enhances electroencephalographic (EEG) α-oscillation long after tACS-offset. Two mechanisms have been suggested to underlie these changes in oscillatory EEG activity: tACS-induced entrainment of brain oscillations and/or tACS-induced changes in oscillatory circuits by spike-timing dependent plasticity. Objective We tested to what extent plasticity can account for tACS-aftereffects when controlling for entrainment “echoes.” To this end, we used a novel, intermittent tACS protocol and investigated the strength of the aftereffect as a function of phase continuity between successive tACS episodes, as well as the match between stimulation frequency and endogenous α-frequency. Methods 12 healthy participants were stimulated at around individual α-frequency for 11–15 min in four sessions using intermittent tACS or sham. Successive tACS events were either phase-continuous or phase-discontinuous, and either 3 or 8 s long. EEG α-phase and power changes were compared after and between episodes of α-tACS across conditions and against sham. Results α-aftereffects were successfully replicated after intermittent stimulation using 8-s but not 3-s trains. These aftereffects did not reveal any of the characteristics of entrainment echoes in that they were independent of tACS phase-continuity and showed neither prolonged phase alignment nor frequency synchronization to the exact stimulation frequency. Conclusion Our results indicate that plasticity mechanisms are sufficient to explain α-aftereffects in response to α-tACS, and inform models of tACS-induced plasticity in oscillatory circuits. Modifying brain oscillations with tACS holds promise for clinical applications in disorders involving abnormal neural synchrony. PMID:25648377

  13. Circadian analysis of large human populations: inferences from the power grid.

    PubMed

    Stowie, Adam C; Amicarelli, Mario J; Crosier, Caitlin J; Mymko, Ryan; Glass, J David

    2015-03-01

    Few, if any studies have focused on the daily rhythmic nature of modern industrialized populations. The present study utilized real-time load data from the U.S. Pacific Northwest electrical power grid as a reflection of human operative household activity. This approach involved actigraphic analyses of continuously streaming internet data (provided in 5 min bins) from a human subject pool of approximately 43 million primarily residential users. Rhythm analyses reveal striking seasonal and intra-week differences in human activity patterns, largely devoid of manufacturing and automated load interference. Length of the diurnal activity period (alpha) is longer during the spring than the summer (16.64 h versus 15.98 h, respectively; p < 0.01). As expected, significantly more activity occurs in the solar dark phase during the winter than during the summer (6.29 h versus 2.03 h, respectively; p < 0.01). Interestingly, throughout the year a "weekend effect" is evident, where morning activity onset occurs approximately 1 h later than during the work week (5:54 am versus 6:52 am, respectively; p < 0.01). This indicates a general phase-delaying response to the absence of job-related or other weekday morning arousal cues, substantiating a preference or need to sleep longer on weekends. Finally, a shift in onset time can be seen during the transition to Day Light Saving Time, but not the transition back to Standard Time. The use of grid power load as a means for human actimetry assessment thus offers new insights into the collective diurnal activity patterns of large human populations. PMID:25286134

  14. Sub-micrometer particles produced by a low-powered AC electric arc in liquids.

    PubMed

    Jaworski, Jacek A; Fleury, Eric

    2012-01-01

    The article presents the report of the production of composites of sub-micrometer metal particles in matrix consisted of the metal compounds by means of an AC electric arc in water and paraffin solutions using electrodes carbon-metal and metal-metal (metal: Ni, Fe, Co, Cu). The advantage of this method is the low electric power (from 5 to 10 W) needed in comparison to standard DC arc-discharge methods (0.8 to 3 kW). This method enables the production of particles from conductive material also in wide range of temperature and in solvent which could be either transparent to light or opaque. Moreover the solvent can be electrolyte or insulating liquid. The microstructure of the composite layer was investigated by scanning electron microscopy (SEM), Electron Probe Microanalysis (EPMA) and X-ray. During particles production in water metal oxides were created. Additionally using cobalt-copper, nickel-copper as couple electrodes, insoluble in water copper (II) hydroxide crystal grains were created additionally which crystals shape was depended on transition metal. For iron-copper couple electrodes system the copper (II) hydroxide was not formed. Experiments with sequence production of Ni and Fe particles with C electrode assisting in molten paraffin let to obtain both Ni and Fe particles surrounded by paraffin. After solidification the material was insulator but if locally magnetic field influenced on the liquid solution in that place after solidification a new composite was created which was electric current conductor with resistivity around 0.1 omega x m, was attracted by magnetic field and presented magneto resistance around 0.4% in changing magnetic field in a range 150 mT. After mixing the concentrated paraffin with normal paraffin resistivity of the mixture increased and it became photosensitive and created small voltage under light influence. PMID:22524027

  15. What day-ahead reserves are needed in electric grids with high levels of wind power?

    NASA Astrophysics Data System (ADS)

    Mauch, Brandon; Apt, Jay; Carvalho, Pedro M. S.; Jaramillo, Paulina

    2013-09-01

    Day-ahead load and wind power forecasts provide useful information for operational decision making, but they are imperfect and forecast errors must be offset with operational reserves and balancing of (real time) energy. Procurement of these reserves is of great operational and financial importance in integrating large-scale wind power. We present a probabilistic method to determine net load forecast uncertainty for day-ahead wind and load forecasts. Our analysis uses data from two different electric grids in the US with similar levels of installed wind capacity but with large differences in wind and load forecast accuracy, due to geographic characteristics. We demonstrate that the day-ahead capacity requirements can be computed based on forecasts of wind and load. For 95% day-ahead reliability, this required capacity ranges from 2100 to 5700 MW for ERCOT, and 1900 to 4500 MW for MISO (with 10 GW of installed wind capacity), depending on the wind and load forecast values. We also show that for each MW of additional wind power capacity for ERCOT, 0.16-0.30 MW of dispatchable capacity will be used to compensate for wind uncertainty based on day-ahead forecasts. For MISO (with its more accurate forecasts), the requirement is 0.07-0.13 MW of dispatchable capacity for each MW of additional wind capacity.

  16. Naturalistic Decision Making in Power Grid Operations: Implications for Dispatcher Training and Usability Testing

    SciTech Connect

    Greitzer, Frank L.; Podmore, Robin

    2008-11-17

    The focus of the present study is on improved training approaches to accelerate learning and improved methods for analyzing effectiveness of tools within a high-fidelity power grid simulated environment. A theory-based model has been developed to document and understand the mental processes that an expert power system operator uses when making critical decisions. The theoretical foundation for the method is based on the concepts of situation awareness, the methods of cognitive task analysis, and the naturalistic decision making (NDM) approach of Recognition Primed Decision Making. The method has been systematically explored and refined as part of a capability demonstration of a high-fidelity real-time power system simulator under normal and emergency conditions. To examine NDM processes, we analyzed transcripts of operator-to-operator conversations during the simulated scenario to reveal and assess NDM-based performance criteria. The results of the analysis indicate that the proposed framework can be used constructively to map or assess the Situation Awareness Level of the operators at each point in the scenario. We can also identify the mental models and mental simulations that the operators employ at different points in the scenario. This report documents the method, describes elements of the model, and provides appendices that document the simulation scenario and the associated mental models used by operators in the scenario.

  17. Analysis and experimental verification of new power flow control for grid-connected inverter with LCL filter in microgrid.

    PubMed

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method. PMID:24672304

  18. Location, duration, and power; How Americans' driving habits and charging infrastructure inform vehicle-grid interactions

    NASA Astrophysics Data System (ADS)

    Pearre, Nathaniel S.

    The substitution of electrical energy for gasoline as a transportation fuel is an initiative both with a long history, and one made both pressing and important in today's policy discussion by renewed interest in plug-in vehicles. The research presented in this dissertation attempts to inform the policy discussion for governments, for electric utilities, for the makers of electric cars, and for the industries developing and planning charging infrastructure. To that end, the impacts of variations to several possible system design parameters, on several metrics of evaluation, are assessed. The analysis is based on a dataset of vehicle trips collected by Georgia Institute of Technology, tracking almost 500 vehicles that commute to, from or within the Atlanta city center, comprising Atlanta `commuter-shed'. By assuming that this dataset of trips defines the desired travel behavior of urban and suburban American populations, the effects of travel electrification in personal vehicles can be assessed. Several significant and novel findings have emerged from this research. These include the conclusion that at-work charging is not necessarily the logical next step beyond home-charging, as it will in general add little to the substitutability of electric vehicles. In contrast, high power en-route charging, combined with modest power home charging is shown to be surprisingly effective, potentially requiring of EV drivers a total time spent at en-route recharging stations similar to that for liquid fueled cars. From the vehicle marketing perspective, a quantification of the hybrid household effect, wherein multi-vehicle households own one EV, showed that about a quarter of all households could adopt a vehicle with 80 miles of range with no changes to travel patterns. Of interest to grid management, this research showed an apparent maximum fleet-wide load from unregulated charging of about 1 kW per vehicle, regardless of EVSE power or EV battery size. This contrasts with a

  19. Modeling of High-Power Gas Switch for Electric Grid System

    NASA Astrophysics Data System (ADS)

    Khrabrov, Alexander V.; Carlsson, Johan; Kaganovich, Igor D.; Sommerer, Timothy; Zalubovsky, Sergey

    2014-10-01

    There has been recent interest in utilizing gas switches in high-power AC/DC conversion for the purpose of power transmission over long distances. These devices would be based on a glow discharge with magnetically insulated cold cathode. Their operation is similar to sputtering magnetrons [2,3], but at much higher pressures (0.1 to 1 Torr) in order to achieve high current densities. We present results of numerical (the particle-in-cell code EDIPIC 1d3v PIC) and analytical investigation of a gas switch in the conduction phase. The important properties of the high-pressure magnetron discharge are a very narrow cathode sheath and a considerable voltage drop in the magnetized pre-sheath where most of the ionization takes place due to Joule heating. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000298.

  20. Characterization of combined power plasma jet using AC high voltage and nanosecond pulse for reactive species composition control

    NASA Astrophysics Data System (ADS)

    Takashima, Keisuke; Konishi, Hideaki; Kato, Toshiaki; Kaneko, Toshiro

    2014-10-01

    In the application studies for both bio-medical and agricultural applications, the roles of the reactive oxide and/or nitride species generated in the plasma has been reported as a key to control the effects and ill-effects on the living organism. The correlation between total OH radical exposure from an air atmospheric pressure plasma jet and the sterilization threshold on Botrytis cinerea is presented. With the increase of the OH radical exposure to the Botrytis cinerea, the probability of sterilization is increased. In this study, to resolve the roles of reactive species including OH radicals, a combined power plasma jet using nanosecond pulses and low-frequency sinusoidal AC high voltage (a few kHz) is studied for controlling the composition of the reactive species. The nanosecond pulses are superimposed on the AC voltage which is in synchronization with the AC phase. The undergoing work to characterize the combined power discharge with electric charge and voltage cycle on the plasma jet will also be presented to discuss the discharge characteristics to control the composition of the reactive species.

  1. A Study of Energy Management Systems and its Failure Modes in Smart Grid Power Distribution

    NASA Astrophysics Data System (ADS)

    Musani, Aatif

    The subject of this thesis is distribution level load management using a pricing signal in a smart grid infrastructure. The project relates to energy management in a spe-cialized distribution system known as the Future Renewable Electric Energy Delivery and Management (FREEDM) system. Energy management through demand response is one of the key applications of smart grid. Demand response today is envisioned as a method in which the price could be communicated to the consumers and they may shift their loads from high price periods to the low price periods. The development and deployment of the FREEDM system necessitates controls of energy and power at the point of end use. In this thesis, the main objective is to develop the control model of the Energy Management System (EMS). The energy and power management in the FREEDM system is digitally controlled therefore all signals containing system states are discrete. The EMS is modeled as a discrete closed loop transfer function in the z-domain. A breakdown of power and energy control devices such as EMS components may result in energy con-sumption error. This leads to one of the main focuses of the thesis which is to identify and study component failures of the designed control system. Moreover, H-infinity ro-bust control method is applied to ensure effectiveness of the control architecture. A focus of the study is cyber security attack, specifically bad data detection in price. Test cases are used to illustrate the performance of the EMS control design, the effect of failure modes and the application of robust control technique. The EMS was represented by a linear z-domain model. The transfer function be-tween the pricing signal and the demand response was designed and used as a test bed. EMS potential failure modes were identified and studied. Three bad data detection meth-odologies were implemented and a voting policy was used to declare bad data. The run-ning mean and standard deviation analysis method proves to be

  2. Power management and frequency regulation for microgrid and smart grid: A real-time demand response approach

    NASA Astrophysics Data System (ADS)

    Pourmousavi Kani, Seyyed Ali

    Future power systems (known as smart grid) will experience a high penetration level of variable distributed energy resources to bring abundant, affordable, clean, efficient, and reliable electric power to all consumers. However, it might suffer from the uncertain and variable nature of these generations in terms of reliability and especially providing required balancing reserves. In the current power system structure, balancing reserves (provided by spinning and non-spinning power generation units) usually are provided by conventional fossil-fueled power plants. However, such power plants are not the favorite option for the smart grid because of their low efficiency, high amount of emissions, and expensive capital investments on transmission and distribution facilities, to name a few. Providing regulation services in the presence of variable distributed energy resources would be even more difficult for islanded microgrids. The impact and effectiveness of demand response are still not clear at the distribution and transmission levels. In other words, there is no solid research reported in the literature on the evaluation of the impact of DR on power system dynamic performance. In order to address these issues, a real-time demand response approach along with real-time power management (specifically for microgrids) is proposed in this research. The real-time demand response solution is utilized at the transmission (through load-frequency control model) and distribution level (both in the islanded and grid-tied modes) to provide effective and fast regulation services for the stable operation of the power system. Then, multiple real-time power management algorithms for grid-tied and islanded microgrids are proposed to economically and effectively operate microgrids. Extensive dynamic modeling of generation, storage, and load as well as different controller design are considered and developed throughout this research to provide appropriate models and simulation

  3. 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 ...

  4. Reduced-Order Models for Load Management in the Power Grid

    NASA Astrophysics Data System (ADS)

    Alizadeh, Mahnoosh

    In recent years, considerable research efforts have been directed towards designing control schemes that can leverage the inherent flexibility of electricity demand that is not tapped into in today's electricity markets. It is expected that these control schemes will be carried out by for-profit entities referred to as aggregators that operate at the edge of the power grid network. While the aggregator control problem is receiving much attention, more high-level questions of how these aggregators should plan their market participation, interact with the main grid and with each other, remain rather understudied. Answering these questions requires a large-scale model for the aggregate flexibility that can be harnessed from the a population of customers, particularly for residences and small businesses. The contribution of this thesis towards this goal is divided into three parts: In Chapter 3, a reduced-order model for a large population of heterogeneous appliances is provided by clustering load profiles that share similar degrees of freedom together. The use of such reduced-order model for system planning and optimal market decision making requires a foresighted approximation of the number of appliances that will join each cluster. Thus, Chapter 4 provides a systematic framework to generate such forecasts for the case of Electric Vehicles, based on real-world battery charging data. While these two chapters set aside the economic side that is naturally involved with participation in demand response programs and mainly focus on the control problem, Chapter 5 is dedicated to the study of optimal pricing mechanisms in order to recruit heterogeneous customers in a demand response program in which an aggregator can directly manage their appliances' load under their specified preferences. Prices are proportional to the wholesale market savings that can result from each recruitment event.

  5. System and method for design and optimization of grid connected photovoltaic power plant with multiple photovoltaic module technologies

    DOEpatents

    Thomas, Bex George; Elasser, Ahmed; Bollapragada, Srinivas; Galbraith, Anthony William; Agamy, Mohammed; Garifullin, Maxim Valeryevich

    2016-03-29

    A system and method of using one or more DC-DC/DC-AC converters and/or alternative devices allows strings of multiple module technologies to coexist within the same PV power plant. A computing (optimization) framework estimates the percentage allocation of PV power plant capacity to selected PV module technologies. The framework and its supporting components considers irradiation, temperature, spectral profiles, cost and other practical constraints to achieve the lowest levelized cost of electricity, maximum output and minimum system cost. The system and method can function using any device enabling distributed maximum power point tracking at the module, string or combiner level.

  6. The Optimized Operation of Gas Turbine Combined Heat and Power Units Oriented for the Grid-Connected Control

    NASA Astrophysics Data System (ADS)

    Xia, Shu; Ge, Xiaolin

    2016-04-01

    In this study, according to various grid-connected demands, the optimization scheduling models of Combined Heat and Power (CHP) units are established with three scheduling modes, which are tracking the total generation scheduling mode, tracking steady output scheduling mode and tracking peaking curve scheduling mode. In order to reduce the solution difficulty, based on the principles of modern algebraic integers, linearizing techniques are developed to handle complex nonlinear constrains of the variable conditions, and the optimized operation problem of CHP units is converted into a mixed-integer linear programming problem. Finally, with specific examples, the 96 points day ahead, heat and power supply plans of the systems are optimized. The results show that, the proposed models and methods can develop appropriate coordination heat and power optimization programs according to different grid-connected control.

  7. Relative accuracy of grid references derived from postcode and address in UK epidemiological studies of overhead power lines.

    PubMed

    Swanson, J; Vincent, T J; Bunch, K J

    2014-12-01

    In the UK, the location of an address, necessary for calculating the distance to overhead power lines in epidemiological studies, is available from different sources. We assess the accuracy of each. The grid reference specific to each address, provided by the Ordnance Survey product Address-Point, is generally accurate to a few metres, which will usually be sufficient for calculating magnetic fields from the power lines. The grid reference derived from the postcode rather than the individual address is generally accurate to tens of metres, and may be acceptable for assessing effects that vary in the general proximity of the power line, but is probably not acceptable for assessing magnetic-field effects. PMID:25325707

  8. Co-optimizing Generation and Transmission Expansion with Wind Power in Large-Scale Power Grids Implementation in the US Eastern Interconnection

    DOE PAGESBeta

    You, Shutang; Hadley, Stanton W.; Shankar, Mallikarjun; Liu, Yilu

    2016-01-12

    This paper studies the generation and transmission expansion co-optimization problem with a high wind power penetration rate in the US Eastern Interconnection (EI) power grid. In this paper, the generation and transmission expansion problem for the EI system is modeled as a mixed-integer programming (MIP) problem. Our paper also analyzed a time series generation method to capture the variation and correlation of both load and wind power across regions. The obtained series can be easily introduced into the expansion planning problem and then solved through existing MIP solvers. Simulation results show that the proposed planning model and series generation methodmore » can improve the expansion result significantly through modeling more detailed information of wind and load variation among regions in the US EI system. Moreover, the improved expansion plan that combines generation and transmission will aid system planners and policy makers to maximize the social welfare in large-scale power grids.« less

  9. Towards Real-Time High Performance Computing For Power Grid Analysis

    SciTech Connect

    Hui, Peter SY; Lee, Barry; Chikkagoudar, Satish

    2012-11-16

    Real-time computing has traditionally been considered largely in the context of single-processor and embedded systems, and indeed, the terms real-time computing, embedded systems, and control systems are often mentioned in closely related contexts. However, real-time computing in the context of multinode systems, specifically high-performance, cluster-computing systems, remains relatively unexplored. Imposing real-time constraints on a parallel (cluster) computing environment introduces a variety of challenges with respect to the formal verification of the system's timing properties. In this paper, we give a motivating example to demonstrate the need for such a system--- an application to estimate the electromechanical states of the power grid--- and we introduce a formal method for performing verification of certain temporal properties within a system of parallel processes. We describe our work towards a full real-time implementation of the target application--- namely, our progress towards extracting a key mathematical kernel from the application, the formal process by which we analyze the intricate timing behavior of the processes on the cluster, as well as timing measurements taken on our test cluster to demonstrate use of these concepts.

  10. Design and development of 500 m long HTS cable system in the KEPCO power grid, Korea

    NASA Astrophysics Data System (ADS)

    Sohn, S. H.; Lim, J. H.; Yang, B. M.; Lee, S. K.; Jang, H. M.; Kim, Y. H.; Yang, H. S.; Kim, D. L.; Kim, H. R.; Yim, S. W.; Won, Y. J.; Hwang, S. D.

    2010-11-01

    In Korea, two long-term field demonstrations for high temperature superconducting (HTS) cable have been carried out for several years; Korea Electric Power Corporation (KEPCO) and LS Cable Ltd. (LSC) independently. Encouraged at the result of the projects performed in parallel, a new project targeting the real grid operation was launched in the fourth quarter of 2008 with the Korean government’s financial support. KEPCO and LSC are jointly collaborating in the selection of substation, determination of cable specification, design of cryogenic system, and the scheme of protection coordination. A three phase 500 m long HTS cable at a distribution level voltage of 22.9 kV is to be built at 154/22.9 kV Icheon substation located in near Seoul. A hybrid cryogenic system reflecting the contingency plan is being designed including cryocoolers. The HTS cable system will be installed in the second quarter of 2010, being commissioned by the fall of 2010. This paper describes the objectives of the project and design issues of the cable and cryogenic system in detail.

  11. Management of the geomagnetically induced current risks on the national grid company's electric power transmission system

    NASA Astrophysics Data System (ADS)

    Erinmez, I. Arslan; Kappenman, John G.; Radasky, William A.

    2002-03-01

    The National Grid Company plc (NGC) is the owner and operator of one of the world's largest privatised high-voltage electric power transmission systems in England and Wales at 400 and 275kV. As owner operator it is responsible for the secure and reliable delivery of electrical energy to all the 25 million electricity supply customers in England and Wales. The transmission and distribution systems in UK have experienced significant effects during past geomagnetic storm events especially during solar cycles 21 and 22. These effects included generator reactive power output swings, voltage dips, negative sequence alarms and transformer failures. Geomagnetically induced current (GIC) monitoring was installed in 1989 and operational procedures were put in place based on global solar weather forecasts. These measures were not capable of delivering reliable information and thus gave many false operational alarms. Their only real use was for post event forensic purposes. Since the cycle 22 solar peak activity the UK transmission system has developed to become more meshed, heavily loaded and dependent on the availability of reactive compensation equipment for voltage control. NGC carried out GIC impact risk assessment in 1998. This reviewed available options for managing this risk including investigation of blocking measures, a reliable local GIC forecast, GIC monitoring, a review of transmission equipment capabilities to withstand GIC conditions and operational procedures to manage the risk. As a result of the risk assessment NGC completed installation of a Metatech Spacecast/Powercast space weather forecasting system in May 1999. EPRI Sunburst 2000 based transformer monitoring systems were fully integrated in January 2000 in time for peak solar storm activity in solar cycle 23. This paper will describe the risk analysis undertaken, the risk management processes put in place and the performance of the forecasting and monitoring systems, respectively.

  12. SIMULATION OF DISPERSION OF A POWER PLANT PLUME USING AN ADAPTIVE GRID ALGORITHM

    EPA Science Inventory

    A new dynamic adaptive grid algorithm has been developed for use in air quality modeling. This algorithm uses a higher order numerical scheme?the piecewise parabolic method (PPM)?for computing advective solution fields; a weight function capable of promoting grid node clustering ...

  13. Advanced simulation for analysis of critical infrastructure : abstract cascades, the electric power grid, and Fedwire.

    SciTech Connect

    Glass, Robert John, Jr.; Stamber, Kevin Louis; Beyeler, Walter Eugene

    2004-08-01

    heterogeneous scale-free (fractal) network. For the stylized electric power grid, our initial simulations demonstrate that the addition of geographically unrestricted random transactions can eventually push a grid to cascading failure, thus supporting the hypothesis that actions of unrestrained power markets (without proper security coordination on market actions) can undermine large scale system stability. We also find that network topology greatly influences system robustness. Homogeneous networks that are 'fish-net' like can withstand many more transaction perturbations before cascading than can scale-free networks. Interestingly, when the homogeneous network finally cascades, it tends to fail in its entirety, while the scale-free tends to compartmentalize failure and thus leads to smaller, more restricted outages. In the case of stylized Fedwire, initial simulations show that as banks adaptively set their individual reserves in response to random transactions, the ratio of the total volume of transactions to individual reserves, or 'turnover ratio', increases with increasing volume. The removal of a bank from interaction within the network then creates a cascade, its speed of propagation increasing as the turnover ratio increases. We also find that propagation is accelerated by patterned transactions (as expected to occur within real markets) and in scale-free networks, by the 'attack' of the most highly connected bank. These results suggest that the time scale for intervention by the Federal Reserve to divert a cascade in Fedwire may be quite short. Ongoing work in our cascade analysis effort is building on both these specific stylized applications to enhance their fidelity as well as embracing new applications. We are implementing markets and additional network interactions (e.g., social, telecommunication, information gathering, and control) that can impose structured drives (perturbations) comparable to those seen in real systems. Understanding the interaction of

  14. PhotoVoltaic distributed generation for Lanai power grid real-time simulation and control integration scenario.

    SciTech Connect

    Robinett, Rush D., III; Kukolich, Keith; Wilson, David Gerald; Schenkman, Benjamin L.

    2010-06-01

    This paper discusses the modeling, analysis, and testing in a real-time simulation environment of the Lanai power grid system for the integration and control of PhotoVoltaic (PV) distributed generation. The Lanai Island in Hawaii is part of the Hawaii Clean Energy Initiative (HCEI) to transition to 30% renewable green energy penetration by 2030. In Lanai the primary loads come from two Castle and Cook Resorts, in addition to residential needs. The total peak load profile is 12470 V, 5.5 MW. Currently there are several diesel generators that meet these loading requirements. As part of the HCEI, Lanai has initially installed 1.2 MW of PV generation. The goal of this study has been to evaluate the impact of the PV with respect to the conventional carbon-based diesel generation in real time simulation. For intermittent PV distributed generation, the overall stability and transient responses are investigated. A simple Lanai 'like' model has been developed in the Matlab/Simulink environment (see Fig. 1) and to accommodate real-time simulation of the hybrid power grid system the Opal-RT Technologies RT-Lab environment is used. The diesel generators have been modelled using the SimPowerSystems toolbox swing equations and a custom Simulink module has been developed for the High level PV generation. All of the loads have been characterized primarily as distribution lines with series resistive load banks with one VAR load bank. Three-phase faults are implemented for each bus. Both conventional and advanced control architectures will be used to evaluate the integration of the PV onto the current power grid system. The baseline numerical results include the stable performance of the power grid during varying cloud cover (PV generation ramping up/down) scenarios. The importance of assessing the real-time scenario is included.

  15. Grid oscillators

    NASA Technical Reports Server (NTRS)

    Popovic, Zorana B.; Kim, Moonil; Rutledge, David B.

    1988-01-01

    Loading a two-dimensional grid with active devices offers a means of combining the power of solid-state oscillators in the microwave and millimeter-wave range. The grid structure allows a large number of negative resistance devices to be combined. This approach is attractive because the active devices do not require an external locking signal, and the combining is done in free space. In addition, the loaded grid is a planar structure amenable to monolithic integration. Measurements on a 25-MESFET grid at 9.7 GHz show power-combining and frequency-locking without an external locking signal, with an ERP of 37 W. Experimental far-field patterns agree with theoretical results obtained using reciprocity.

  16. Study on AC-DC Electrical Conductivities in Warm Dense Matter Generated by Pulsed-power Discharge with Isochoric Vessel

    NASA Astrophysics Data System (ADS)

    Sasaki, Toru; Ohuchi, Takumi; Takahashi, Takuya; Kawaguchi, Yoshinari; Saito, Hirotaka; Miki, Yasutoshi; Takahashi, Kazumasa; Kikuchi, Takashi; Aso, Tsukasa; Harada, Nob.

    2016-03-01

    To observe AC and DC electrical conductivity in warm dense matter (WDM), we have demonstrated to apply the spectroscopic ellipsometry for a pulsed-power discharge with isochoric vessel. At 10 μs from the beginning of discharge, the generated parameters by using pulsed-power discharge with isochoric vessel are 0.1 ρ s (ρ s: solid density) of density and 4000 K of temperature, respectively. The DC electrical conductivity for above parameters is estimated to be 104 S/m. In order to measure the AC electrical conductivity, we have developed a four-detector spectroscopic ellipsometer with a multichannel spectrometer. The multichannel spectrometer, in which consists of a 16-channel photodiode array, a two-stages voltage adder, and a flat diffraction grating, has 10 MHz of the frequency response with covered visible spectrum. For applying the four-detector spectroscopic ellipsometer, we observe the each observation signal evolves the polarized behavior compared to the ratio as I 1/I 2.

  17. An Advanced User Interface Approach for Complex Parameter Study Process Specification in the Information Power Grid

    NASA Technical Reports Server (NTRS)

    Yarrow, Maurice; McCann, Karen M.; Biswas, Rupak; VanderWijngaart, Rob; Yan, Jerry C. (Technical Monitor)

    2000-01-01

    The creation of parameter study suites has recently become a more challenging problem as the parameter studies have now become multi-tiered and the computational environment has become a supercomputer grid. The parameter spaces are vast, the individual problem sizes are getting larger, and researchers are now seeking to combine several successive stages of parameterization and computation. Simultaneously, grid-based computing offers great resource opportunity but at the expense of great difficulty of use. We present an approach to this problem which stresses intuitive visual design tools for parameter study creation and complex process specification, and also offers programming-free access to grid-based supercomputer resources and process automation.

  18. Maximum power tracking

    SciTech Connect

    O'Sullivan, G.

    1983-03-01

    By definition, a maximum power tracking device causes the photovoltaic array to operate on the locus of maximum power points within a specified accuracy. There are limitations to the application of maximum power tracking. A prerequisite is that the load be capable of absorbing all of the power availble at all times. Battery chargers, electrical heaters, water pumps, and most significantly, returning power to the utility grid, are prime examples of applications that are adaptable to maximum power tracking. Maximum power tracking is available to either dc or ac loads. An inverter equipped with a means of changing input voltage by controlling its input impedance can deliver maximum power to ac loads. The inverter can be fixed or variable frequency and fixed or variable voltage, but must be compatible with the ac load. The discussion includes applications, techniques, and cost factors.

  19. A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard

    NASA Astrophysics Data System (ADS)

    Vennemann, T.; Frye, T.; Liu, Z.; Kahmann, M.; Mathis, W.

    2015-11-01

    In this paper we present an analytical formulation of a Zero Position Coding (ZePoC) encoder for an AC power standard based on class-D topologies. For controlling a class-D power stage a binary signal with special spectral characteristics will be generated by this ZePoC encoder for sinusoidal signals. These spectral characteristics have a predictable accuracy within a separated baseband to keep the noise floor below a specified level. Simulation results will validate the accuracy of this novel ZePoC encoder. For a real-time implementation of the encoder on a DSP/FPGA hardware architecture a trade-off between accuracy and speed of the ZePoC algorithm has to be made. Therefore the numerical effects of different floating point formats will be analyzed.

  20. Constructing criteria to diagnose the likelihood of extreme events in the case of the electric power grid.

    PubMed

    van Milligen, B Ph; Carreras, B A; Newman, D E

    2016-03-01

    A set of new criteria for the diagnosis of the possible occurrence of a large blackout are constructed, using the output from a model for the dynamics of the electric power grid (the OPA model). The approach used is to look for maximum values of the Transfer Entropy between time series of the system variables and the time series of large blackouts. The best criterion is found by looking at the number of overloaded lines at the beginning of the day. PMID:27036187

  1. Constructing criteria to diagnose the likelihood of extreme events in the case of the electric power grid

    NASA Astrophysics Data System (ADS)

    van Milligen, B. Ph.; Carreras, B. A.; Newman, D. E.

    2016-03-01

    A set of new criteria for the diagnosis of the possible occurrence of a large blackout are constructed, using the output from a model for the dynamics of the electric power grid (the OPA model). The approach used is to look for maximum values of the Transfer Entropy between time series of the system variables and the time series of large blackouts. The best criterion is found by looking at the number of overloaded lines at the beginning of the day.

  2. Stability, Transient Response, Control, and Safety of a High-Power Electric Grid for Turboelectric Propulsion of Aircraft

    NASA Technical Reports Server (NTRS)

    Armstrong, Michael; Ross, Christine; Phillips, Danny; Blackwelder, Mark

    2013-01-01

    This document contains the deliverables for the NASA Research and Technology for Aerospace Propulsion Systems (RTAPS) regarding the stability, transient response, control, and safety study for a high power cryogenic turboelectric distributed propulsion (TeDP) system. The objective of this research effort is to enumerate, characterize, and evaluate the critical issues facing the development of the N3-X concept aircraft. This includes the proposal of electrical grid architecture concepts and an evaluation of any needs for energy storage.

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

    SciTech Connect

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

    2006-03-01

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

  4. Powering a Home with Just 25 Watts of Solar PV. Super-Efficient Appliances Can Enable Expanded Off-Grid Energy Service Using Small Solar Power Systems

    SciTech Connect

    Phadke, Amol A.; Jacobson, Arne; Park, Won Young; Lee, Ga Rick; Alstone, Peter; Khare, Amit

    2015-04-01

    Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africa and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.

  5. A Study of the Relationship between Weather Variables and Electric Power Demand inside a Smart Grid/Smart World Framework

    PubMed Central

    Hernández, Luis; Baladrón, Carlos; Aguiar, Javier M.; Calavia, Lorena; Carro, Belén; Sánchez-Esguevillas, Antonio; Cook, Diane J.; Chinarro, David; Gómez, Jorge

    2012-01-01

    One of the main challenges of today's society is the need to fulfill at the same time the two sides of the dichotomy between the growing energy demand and the need to look after the environment. Smart Grids are one of the answers: intelligent energy grids which retrieve data about the environment through extensive sensor networks and react accordingly to optimize resource consumption. In order to do this, the Smart Grids need to understand the existing relationship between energy demand and a set of relevant climatic variables. All smart “systems” (buildings, cities, homes, consumers, etc.) have the potential to employ their intelligence for self-adaptation to climate conditions. After introducing the Smart World, a global framework for the collaboration of these smart systems, this paper presents the relationship found at experimental level between a range of relevant weather variables and electric power demand patterns, presenting a case study using an agent-based system, and emphasizing the need to consider this relationship in certain Smart World (and specifically Smart Grid and microgrid) applications.

  6. Micro-grid for on-site wind-and-hydrogen powered generation

    NASA Astrophysics Data System (ADS)

    Suskis, P.; Andreiciks, A.; Steiks, I.; Krievs, O.; Kleperis, J.

    2014-02-01

    The authors propose a micro-grid for autonomous wind-and-hydrogen power generation thus replacing such traditional fossil-fuelled equipment as domestic diesel generators, gas micro-turbines, etc. In the proposed microgrid the excess of electrical energy from a wind turbine is spent on electrolytic production of hydrogen which is then stored under low-pressure in absorbing composite material. The electrolyser has a non-traditional feeding unit and electrode coatings. The proposed DC/DC conversion topologies for different micro-grid nodes are shown to be well-designed. The prototypes elaborated for the converters and hydrogen storage media were tested and have demonstrated a good performance. Rakstā piedāvātā mikrotīkla izpēte ir veikta ar mērķi izstrādāt autonomu, uz vēja un ūdeņraža enerģiju balstītu elektroapgādes sistēmu, kas varētu aizvietot tradicionālās fosilā kurināmā sistēmas, piemēram, mājsaimniecību dīzeļa ģeneratorus, gāzes mikroturbīnas u.c. Mikrotīkla elektroapgādes sistēmā vēja agregāta saražotā elektroenerģija tiek pārveidota atbilstoši standarta maiņsprieguma elektroapgādes parametriem un piegādāta slodzei. Pārpalikusī enerģija tiek pārveidota un uzkrāta ūdeņraža formā, izmantojot elektrolīzes iekārtu un kompozītmateriālu uzkrājēju. Ja pieejamā vēja enerģija nenosedz slodzes enerģijas patēriņu, elektroenerģijas padeves funkciju ar atbilstoša energoelektronikas pārveidotāja palīdzību pārņem ūdeņraža degvielas elements. Ja, savukārt, slodzei nav nepieciešama enerģija, no vēja saražoto enerģiju izmanto elektrolīzes iekārta un tā tiek uzkrāta ūdeņraža formā, atbilstoši uzkrājēja ietilpībai. Piedāvātajā mikrotīklā ir izmantota elektrolīzes iekārta ar netradicionāliem elektrodu pārklājumiem un barošanas bloku, kā arī zemspiediena kompozītmateriālu ūdeņraža uzkrājējs. Galvenie mikrotīkla elektriskās enerģijas pārveidošanas mezgli ir

  7. Assessing the impact of space weather on the electric power grid based on insurance claims for industrial electrical equipment

    NASA Astrophysics Data System (ADS)

    Schrijver, C. J.; Dobbins, R.; Murtagh, W.; Petrinec, S. M.

    2014-07-01

    Geomagnetically induced currents are known to induce disturbances in the electric power grid. Here we perform a statistical analysis of 11,242 insurance claims from 2000 through 2010 for equipment losses and related business interruptions in North American commercial organizations that are associated with damage to, or malfunction of, electrical and electronic equipment. We find that claim rates are elevated on days with elevated geomagnetic activity by approximately 20% for the top 5% and by about 10% for the top third of most active days ranked by daily maximum variability of the geomagnetic field. When focusing on the claims explicitly attributed to electrical surges (amounting to more than half the total sample), we find that the dependence of claim rates on geomagnetic activity mirrors that of major disturbances in the U.S. high-voltage electric power grid. The claim statistics thus reveal that large-scale geomagnetic variability couples into the low-voltage power distribution network and that related power-quality variations can cause malfunctions and failures in electrical and electronic devices that, in turn, lead to an estimated 500 claims per average year within North America. We discuss the possible magnitude of the full economic impact associated with quality variations in electrical power associated with space weather.

  8. Cygrid: A fast Cython-powered convolution-based gridding module for Python

    NASA Astrophysics Data System (ADS)

    Winkel, B.; Lenz, D.; Flöer, L.

    2016-06-01

    Context. Data gridding is a common task in astronomy and many other science disciplines. It refers to the resampling of irregularly sampled data to a regular grid. Aims: We present cygrid, a library module for the general purpose programming language Python. Cygrid can be used to resample data to any collection of target coordinates, although its typical application involves FITS maps or data cubes. The FITS world coordinate system standard is supported. Methods: The regridding algorithm is based on the convolution of the original samples with a kernel of arbitrary shape. We introduce a lookup table scheme that allows us to parallelize the gridding and combine it with the HEALPix tessellation of the sphere for fast neighbor searches. Results: We show that for n input data points, cygrids runtime scales between O(n) and O(nlog n) and analyze the performance gain that is achieved using multiple CPU cores. We also compare the gridding speed with other techniques, such as nearest-neighbor, and linear and cubic spline interpolation. Conclusions: Cygrid is a very fast and versatile gridding library that significantly outperforms other third-party Python modules, such as the linear and cubic spline interpolation provided by SciPy. http://https://github.com/bwinkel/cygrid

  9. Transport ac loss in a rectangular thin strip with power-law E (J) relation

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Chen, Du-Xing; Fan, Yu; Fang, Jin

    2015-01-01

    Transport ac losses of a rectangular thin strip obeying relation E /Ec =(J /Jc) n with a fixed critical current Ic and n = 5, 10, 20, 30 , and 40 are accurately computed at a fixed frequency f as functions of the current amplitude Im . The results may be interpolated and scaled to those at any values of Ic, f , and 5 ⩽ n ⩽ 40 . Normalized in the same way as that in Norris' analytical formula derived from the critical-state model and converting f to a critical frequency fc , the modeling results may be better compared with the Norris formula and experimental data. A complete set of calculated modeling data are given with necessary formulas to be easily used by experimentalists in any particular case.

  10. Towards risk-based management of critical infrastructures : enabling insights and analysis methodologies from a focused study of the bulk power grid.

    SciTech Connect

    Richardson, Bryan T.; LaViolette, Randall A.; Cook, Benjamin Koger

    2008-02-01

    This report summarizes research on a holistic analysis framework to assess and manage risks in complex infrastructures, with a specific focus on the bulk electric power grid (grid). A comprehensive model of the grid is described that can approximate the coupled dynamics of its physical, control, and market components. New realism is achieved in a power simulator extended to include relevant control features such as relays. The simulator was applied to understand failure mechanisms in the grid. Results suggest that the implementation of simple controls might significantly alter the distribution of cascade failures in power systems. The absence of cascade failures in our results raises questions about the underlying failure mechanisms responsible for widespread outages, and specifically whether these outages are due to a system effect or large-scale component degradation. Finally, a new agent-based market model for bilateral trades in the short-term bulk power market is presented and compared against industry observations.

  11. Modelling and control synthesis of a micro-combined heat and power interface for a concentrating solar power system in off-grid rural power applications

    NASA Astrophysics Data System (ADS)

    Prinsloo, Gerro; Dobson, Robert; Brent, Alan; Mammoli, Andrea

    2016-05-01

    Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

  12. Hiding objects in AC magnetic fields of power grid frequency by two-shell ferromagnetic/superconducting cloak

    NASA Astrophysics Data System (ADS)

    Šouc, J.; Solovyov, M.; Gömöry, F.

    2016-07-01

    Performance of magnetic cloak made from commercially available materials has been tested by verifying its ability to suppress the magnetic signatures of metallic and ferromagnetic objects. The range of magnetic field amplitudes from 0.1 to 10 mT and frequencies around 50-60 Hz were used. The cloak combines the inner tube from high-temperature superconductor that should be cooled by liquid nitrogen, with the outer tube made from MnZn ferrite powder mixed in plastic matter. Superconductor is in the form of tapes wound in helical manner on a round former. Such design is promising when the objects with dimensions reaching several centimeters should be cloaked. Performance of the small model manufactured following this design was demonstrated by observing ˜20 times reduction of the magnetic signature of metallic or ferromagnetic objects.

  13. The power of structural modeling of sub-grid scales - application to astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Georgiev Vlaykov, Dimitar; Grete, Philipp

    2015-08-01

    In numerous astrophysical phenomena the dynamical range can span 10s of orders of magnitude. This implies more than billions of degrees-of-freedom and precludes direct numerical simulations from ever being a realistic possibility. A physical model is necessary to capture the unresolved physics occurring at the sub-grid scales (SGS).Structural modeling is a powerful concept which renders itself applicable to various physical systems. It stems from the idea of capturing the structure of the SGS terms in the evolution equations based on the scale-separation mechanism and independently of the underlying physics. It originates in the hydrodynamics field of large-eddy simulations. We apply it to the study of astrophysical MHD.Here, we present a non-linear SGS model for compressible MHD turbulence. The model is validated a priori at the tensorial, vectorial and scalar levels against of set of high-resolution simulations of stochastically forced homogeneous isotropic turbulence in a periodic box. The parameter space spans 2 decades in sonic Mach numbers (0.2 - 20) and approximately one decade in magnetic Mach number ~(1-8). This covers the super-Alfvenic sub-, trans-, and hyper-sonic regimes, with a range of plasma beta from 0.05 to 25. The Reynolds number is of the order of 103.At the tensor level, the model components correlate well with the turbulence ones, at the level of 0.8 and above. Vectorially, the alignment with the true SGS terms is encouraging with more than 50% of the model within 30° of the data. At the scalar level we look at the dynamics of the SGS energy and cross-helicity. The corresponding SGS flux terms have median correlations of ~0.8. Physically, the model represents well the two directions of the energy cascade.In comparison, traditional functional models exhibit poor local correlations with the data already at the scalar level. Vectorially, they are indifferent to the anisotropy of the SGS terms. They often struggle to represent the energy

  14. Review of the Structure of Bulk Power Markets Grid of the Future White Paper

    SciTech Connect

    Kirby, B.J.

    2000-05-02

    This paper is intended to provide an understanding of the needs of a restructured electricity market and some of the market methods and systems that have developed to address those needs. Chapter 2 discusses the historic market framework of vertically integrated utilities. Chapter 3 introduces the changes to the vertically integrated utility brought about by restructuring. It discusses generation and transmission planning, control and the regulatory process. It also summarizes reliability, security and adequacy. Chapter 4 discusses the basic structures of generation and transmission markets along with transmission-congestion contracts (TCCs) and transmission pricing principles. A discussion is given of the 12 ancillary services needed to reliably operate the power system. Chapter 4 also deals with the role of transmission in opening up markets to competition. In California increments (incs) and decrements (decs) are bid to overcome price differences in different zones caused by congestion. In PJM, any member can purchase Fixed Transmission Rights (FTRs) which allows the member to ''collect rent'' on congested lines and essentially obtain a hedge against congestion. There has been a worrisome slowdown in the growth of the transmission system in the United States since about the mid 70's. However, there are methods for providing incentives for construction of new transmission using tariffs. The California and PJM transmission planning processes are outlined. The Federal Energy Regulatory Commission (FERC) has recently issued a proposed rulemaking on Regional Transmission Organizations (RTOs) which stated that the traditional methods of grid management are showing signs of strain and may be inadequate to support efficient and reliable transmission operations. Chapter 5 provides examples of market implementations and a discussion of the price spikes seen in the Midwest in the summers of 1998 and 1999. An examination of six restructured market systems is performed in

  15. Four Federal Grid-Connected Photovoltaic Systems: Powering Our Nation's Capital with Solar

    SciTech Connect

    Plympton, P.; Kappaz, P.; Kroposki, B.; Stafford, B.; Thornton, J.

    2001-04-16

    One of the fastest growing markets for photovoltaics (PV) is the urban sector. Municipal planners have discovered that PV systems operate favorably in their urban areas, and can be aesthetically integrated into the urban landscape. The federal government has a long history of using PV in a variety of applications, but until recently few applications have been in urban environments. During the last five years, four grid-connected PV systems have been installed on federally owned or federally leased facilities in the Washington, D.C. area: (1) Earth Day Park, (2) U.S. Department of Energy Headquarters, (3) the Pentagon, and (4) Federal Energy Regulatory Commission Headquarters. This paper reviews these four urban, grid-connected systems-particularly the issues of siting, permitting, and grid interconnection.

  16. NPSS on NASA's Information Power Grid: Using CORBA and Globus to Coordinate Multidisciplinary Aeroscience Applications

    NASA Technical Reports Server (NTRS)

    Lopez, Isaac; Follen, Gregory J.; Gutierrez, Richard; Foster, Ian; Ginsburg, Brian; Larsson, Olle; Martin, Stuart; Tuecke, Steven; Woodford, David

    2000-01-01

    This paper describes a project to evaluate the feasibility of combining Grid and Numerical Propulsion System Simulation (NPSS) technologies, with a view to leveraging the numerous advantages of commodity technologies in a high-performance Grid environment. A team from the NASA Glenn Research Center and Argonne National Laboratory has been studying three problems: a desktop-controlled parameter study using Excel (Microsoft Corporation); a multicomponent application using ADPAC, NPSS, and a controller program-, and an aviation safety application running about 100 jobs in near real time. The team has successfully demonstrated (1) a Common-Object- Request-Broker-Architecture- (CORBA-) to-Globus resource manager gateway that allows CORBA remote procedure calls to be used to control the submission and execution of programs on workstations and massively parallel computers, (2) a gateway from the CORBA Trader service to the Grid information service, and (3) a preliminary integration of CORBA and Grid security mechanisms. We have applied these technologies to two applications related to NPSS, namely a parameter study and a multicomponent simulation.

  17. Building resilient power grids from integrated risk governance perspective: A lesson learned from china's 2008 Ice-Snow Storm disaster

    NASA Astrophysics Data System (ADS)

    Ye, Qian

    2014-10-01

    In the past three decades, the electric energy industry made great contribution to support rapid social and economic development in China, and meanwhile has been grown at the highest rate in the human history owing to the economic reform. In its new national development plan, more investment has been put into installation of both electricity generating capacity and transmitting capacity in order to meet fast growing demand of electric energy. However, energy resources, both fossil fuel and renewable types, and energy consumption and load centers in China are not evenly distributed in both spatial and temporal dimensions. Moreover, dominated by coal as its primary energy source, the whole eastern China is now entering an environmental crisis in which pollutants emitted by coal power plants contribute a large part. To balance the regional differences in energy sources and energy consumption while meeting the steadily increasing demands for electric energy for the whole country, in addition to increase electric generating capacity, building large-scale, long-distance ultra high voltage power grids is the top priority for next five years. China is a country prone to almost all kinds of natural disasters due to its vast, complex geographical and climatic conditions. In recent years, frequent natural disasters, especially extreme weather and climate events, have threatened the safety, reliability and stability of electric energy system in China. Unfortunately, with fast growth rate but lacking of risk assessing and prevention mechanism, many infrastructure constructions, including national power grids, are facing integrated and complex economic, social, institutional and ecological risks. In this paper, based on a case analysis of the Great Ice Storm in southern China in January 2008, risks of building a resilient power grid to deal with increasing threats from extreme weathers are discussed. The paper recommends that a systematic approach based on the social

  18. Power conversion distribution system using a resonant high-frequency AC link

    NASA Technical Reports Server (NTRS)

    Sood, P. K.; Lipo, T. A.

    1986-01-01

    Static power conversion systems based on a resonant high frequency (HF) link offers a significant reduction in the size and weight of the equipment over that achieved with conventional approaches, especially when multiple sources and loads are to be integrated. A faster system response and absence of audible noise are the other principal characteristics of such systems. A conversion configuration based on a HF link which is suitable for applications requiring distributed power is proposed.

  19. Validation of the Efficacy of a Solar-Thermal Powered Autoclave System for Off-Grid Medical Instrument Wet Sterilization

    PubMed Central

    Kaseman, Tremayne; Boubour, Jean; Schuler, Douglas A.

    2012-01-01

    This work describes the efficacy of a solar-thermal powered autoclave used for the wet sterilization of medical instruments in off-grid settings where electrical power is not readily available. Twenty-seven trials of the solar-thermal powered system were run using an unmodified non-electric autoclave loaded with a simulated bundle of medical instruments and biological test agents. Results showed that in 100% of the trials the autoclave achieved temperatures in excess of 121°C for 30 minutes, indicator tape displayed visible reactions to steam sterilization, and biological tests showed that microbial agents had been eliminated, in compliance with the Centers for Disease Control and Prevention requirements for efficacious wet sterilization. PMID:22848098

  20. Validation of the efficacy of a solar-thermal powered autoclave system for off-grid medical instrument wet sterilization.

    PubMed

    Kaseman, Tremayne; Boubour, Jean; Schuler, Douglas A

    2012-10-01

    This work describes the efficacy of a solar-thermal powered autoclave used for the wet sterilization of medical instruments in off-grid settings where electrical power is not readily available. Twenty-seven trials of the solar-thermal powered system were run using an unmodified non-electric autoclave loaded with a simulated bundle of medical instruments and biological test agents. Results showed that in 100% of the trials the autoclave achieved temperatures in excess of 121°C for 30 minutes, indicator tape displayed visible reactions to steam sterilization, and biological tests showed that microbial agents had been eliminated, in compliance with the Centers for Disease Control and Prevention requirements for efficacious wet sterilization. PMID:22848098

  1. A Technical, Economic, and Environmental Performance of Grid-Connected Hybrid (Photovoltaic-Wind) Power System in Algeria

    PubMed Central

    Saheb-Koussa, Djohra; Koussa, Mustapha; Said, Nourredine

    2013-01-01

    This paper studies the technical, economic, and environmental analysis of wind and photovoltaic power systems connected to a conventional grid. The main interest in such systems is on-site consumption of the produced energy, system hybridization, pooling of resources, and contribution to the environment protection. To ensure a better management of system energy, models have been used for determining the power that the constituting subsystems can deliver under specific weather conditions. Simulation is performed using MATLAB-SIMULINK. While, the economic and environmental study is performed using HOMER software. From an economic point of view, this allows to compare the financial constraints on each part of the system for the case of Adrar site which is located to the northern part of the south of Algeria. It also permits to optimally size and select the system presenting the best features on the basis of two parameters, that is, cost and effectiveness. From an environmental point of view, this study allows highlighting the role of renewable energy in reducing gas emissions related to greenhouse effects. In addition, through a set of sensitivity analysis, it is found that the wind speed has more effects on the environmental and economic performances of grid-connected hybrid (photovoltaic-wind) power systems. PMID:24489488

  2. Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: II. Solutions and applications

    SciTech Connect

    Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

    2014-10-01

    In a companion manuscript, we developed a novel optimization method for placement, sizing, and operation of Flexible Alternating Current Transmission System (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide Series Compensation (SC) via modification of line inductance. In this manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (~ 2700 nodes and ~ 3300 lines). The results on the 30-bus network are used to study the general properties of the solutions including non-locality and sparsity. The Polish grid is used as a demonstration of the computational efficiency of the heuristics that leverages sequential linearization of power flow constraints and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, the algorithm is able to solve an instance of Polish grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (a) uniform load growth, (b) multiple overloaded configurations, and (c) sequential generator retirements.

  3. Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: II. Solutions and applications

    NASA Astrophysics Data System (ADS)

    Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

    2014-10-01

    In a companion manuscript (Frolov et al 2014 New J. Phys. 16 art. no.) , we developed a novel optimization method for the placement, sizing, and operation of flexible alternating current transmission system (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide series compensation (SC) via modification of line inductance. In this sequel manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (˜2700 nodes and ˜3300 lines). The results from the 30-bus network are used to study the general properties of the solutions, including nonlocality and sparsity. The Polish grid is used to demonstrate the computational efficiency of the heuristics that leverage sequential linearization of power flow constraints, and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, we can use the algorithm to solve a Polish transmission grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (i) uniform load growth, (ii) multiple overloaded configurations, and (iii) sequential generator retirements.

  4. Information Power Grid: Distributed High-Performance Computing and Large-Scale Data Management for Science and Engineering

    NASA Technical Reports Server (NTRS)

    Johnston, William E.; Gannon, Dennis; Nitzberg, Bill; Feiereisen, William (Technical Monitor)

    2000-01-01

    The term "Grid" refers to distributed, high performance computing and data handling infrastructure that incorporates geographically and organizationally dispersed, heterogeneous resources that are persistent and supported. The vision for NASN's Information Power Grid - a computing and data Grid - is that it will provide significant new capabilities to scientists and engineers by facilitating routine construction of information based problem solving environments / frameworks that will knit together widely distributed computing, data, instrument, and human resources into just-in-time systems that can address complex and large-scale computing and data analysis problems. IPG development and deployment is addressing requirements obtained by analyzing a number of different application areas, in particular from the NASA Aero-Space Technology Enterprise. This analysis has focussed primarily on two types of users: The scientist / design engineer whose primary interest is problem solving (e.g., determining wing aerodynamic characteristics in many different operating environments), and whose primary interface to IPG will be through various sorts of problem solving frameworks. The second type of user if the tool designer: The computational scientists who convert physics and mathematics into code that can simulate the physical world. These are the two primary users of IPG, and they have rather different requirements. This paper describes the current state of IPG (the operational testbed), the set of capabilities being put into place for the operational prototype IPG, as well as some of the longer term R&D tasks.

  5. Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: II. Solutions and applications

    DOE PAGESBeta

    Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

    2014-10-01

    In a companion manuscript, we developed a novel optimization method for placement, sizing, and operation of Flexible Alternating Current Transmission System (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide Series Compensation (SC) via modification of line inductance. In this manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (~ 2700 nodes and ~ 3300 lines). The results on the 30-bus network are used to study the general properties of the solutions including non-locality and sparsity. The Polishmore » grid is used as a demonstration of the computational efficiency of the heuristics that leverages sequential linearization of power flow constraints and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, the algorithm is able to solve an instance of Polish grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (a) uniform load growth, (b) multiple overloaded configurations, and (c) sequential generator retirements.« less

  6. Pilot evaluation of electricity-reliability and power-quality monitoring in California's Silicon Valley with the I-Grid(R) system

    SciTech Connect

    Eto, Joseph; Divan, Deepak; Brumsickle, William

    2004-02-01

    Power-quality events are of increasing concern for the economy because today's equipment, particularly computers and automated manufacturing devices, is susceptible to these imperceptible voltage changes. A small variation in voltage can cause this equipment to shut down for long periods, resulting in significant business losses. Tiny variations in power quality are difficult to detect except with expensive monitoring equipment used by trained technicians, so many electricity customers are unaware of the role of power-quality events in equipment malfunctioning. This report describes the findings from a pilot study coordinated through the Silicon Valley Manufacturers Group in California to explore the capabilities of I-Grid(R), a new power-quality monitoring system. This system is designed to improve the accessibility of power-quality in formation and to increase understanding of the growing importance of electricity reliability and power quality to the economy. The study used data collected by I-Grid sensors at seven Silicon Valley firms to investigate the impacts of power quality on individual study participants as well as to explore the capabilities of the I-Grid system to detect events on the larger electricity grid by means of correlation of data from the sensors at the different sites. In addition, study participants were interviewed about the value they place on power quality, and their efforts to address electricity-reliability and power-quality problems. Issues were identified that should be taken into consideration in developing a larger, potentially nationwide, network of power-quality sensors.

  7. Distribution of AC loss in a HTS magnet for SMES with different operating conditions

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Tang, Y.; Ren, L.; Jiao, F.; Song, M.; Cao, K.; Wang, D.; Wang, L.; Dong, H.

    2013-11-01

    The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

  8. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport a.... The device includes straps and a sling to support the patient. (b) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of...

  9. Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

    PubMed Central

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  10. Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

    PubMed

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  11. Integration of HTS Cables in the Future Grid of the Netherlands

    NASA Astrophysics Data System (ADS)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Aanhaanen, G.; Melnik, I.; Geschiere, A.

    Due to increasing power demand, the electricity grid of the Netherlands is changing. The future transmission grid will obtain electrical power generated by decentralized renewable sources, together with large scale generation units located at the coastal region. In this way electrical power has to be distributed and transmitted over longer distances from generation to end user. Potential grid issues like: amount of distributed power, grid stability and electrical loss dissipation merit particular attention. High temperature superconductors (HTS) can play an important role in solving these grid problems. Advantages to integrate HTS components at transmission voltages are numerous: more transmittable power together with less emissions, intrinsic fault current limiting capability, lower ac loss, better control of power flow, reduced footprint, less magnetic field emissions, etc. The main obstacle at present is the relatively high price of HTS conductor. However as the price goes down, initial market penetration of several HTS components (e.g.: cables, fault current limiters) is expected by year 2015. In the full paper we present selected ways to integrate EHV AC HTS cables depending on a particular future grid scenario in the Netherlands.

  12. The response of local power grid at low-latitude to geomagnetic storm: An application of the Hilbert Huang transform

    NASA Astrophysics Data System (ADS)

    Liu, Jin; Wang, Chuan-Bing; Liu, Lu; Sun, Wei-Huai

    2016-04-01

    The Hilbert-Huang transform (HHT) is an adaptive data analysis method that can accommodate the variety of data generated by nonlinear and nonstationary processes in nature. In this paper, we focus on the small geomagnetically induced current (GIC) at the local substations in low-latitude power grid of China, responding to a moderate storm on 14-18 July 2012. The HHT is applied to analyze the neutral point currents (NPCs) of transformers measured at different substations, and the GIC indices converted from local geomagnetic field measurements. The original data are decomposed into intrinsic mode functions (IMFs) using the ensemble empirical mode decomposition. After removal of the quasi-diurnal components related with the solar quiet variation, the IMFs representing storm disturbances are transformed into Hilbert energy spectra. The results show that some transformers have more or less responses to the moderate storm in the form of Hilbert energy spectra with the frequency around 2-3 mHz. A comparison on the amplitude changes of the spectra total energy of NPCs' perturbation during storm time intervals at different sites suggests that a shell type of three-phase single transformer group seems to be more vulnerable in the storm. Although the low-latitude power grids usually show very small GIC, these can be used to investigate the potential risk of space weather to the system.

  13. The Power Semantics in Self and Other Repertory Grid Representations: A Comparison between Obese and Normal-Weight Adult Women

    PubMed Central

    Faccio, Elena; Belloni, Eleonora; Castelnuovo, Gianluca

    2012-01-01

    According to systemic-constructivist theory, all psycho-pathological organizations are linked to specific meanings which are developed by the individual within problematic situations in the context of learning, particularly within the family. The aim of this empirical study is to support the theory that eating disorders are linked to the “power semantics,” concept developed by Ugazio. The hypothesis that the bipolar construct “winner/loser” and the associated meanings are predominant for obese people, has been verified by interviewing 44 women (22 obese/overweight; 22 controls) using the Repertory Grid Test developed by Kelly. The participants’ elicited constructs were classified according to their semantic content and the data compared using statistical techniques. The power semantics were more prevalent and important in the Obese Group than in the Control Group. These results are critically discussed, highlighting possible clinical developments. PMID:23267334

  14. Consumer participation in power market balancing. A real-life step towards smart grids

    NASA Astrophysics Data System (ADS)

    Per, Lund

    2014-09-01

    With the increasing role of wind and solar power, the power balance authorities are facing a big challenge: How to manage the increasing need for fast balancing power brought on by increased penetration of variable and difficult-to-forecast renewable generation? Could more active participation by the residential customers in managing electricity demand be a smart way to go?

  15. Cygrid: Cython-powered convolution-based gridding module for Python

    NASA Astrophysics Data System (ADS)

    Winkel, B.; Lenz, D.; Flöer, L.

    2016-06-01

    The Python module Cygrid grids (resamples) data to any collection of spherical target coordinates, although its typical application involves FITS maps or data cubes. The module supports the FITS world coordinate system (WCS) standard; its underlying algorithm is based on the convolution of the original samples with a 2D Gaussian kernel. A lookup table scheme allows parallelization of the code and is combined with the HEALPix tessellation of the sphere for fast neighbor searches. Cygrid's runtime scales between O(n) and O(nlog n), with n being the number of input samples.

  16. Cost related sensitivity analysis for optimal operation of a grid-parallel PEM fuel cell power plant

    NASA Astrophysics Data System (ADS)

    El-Sharkh, M. Y.; Tanrioven, M.; Rahman, A.; Alam, M. S.

    Fuel cell power plants (FCPP) as a combined source of heat, power and hydrogen (CHP&H) can be considered as a potential option to supply both thermal and electrical loads. Hydrogen produced from the FCPP can be stored for future use of the FCPP or can be sold for profit. In such a system, tariff rates for purchasing or selling electricity, the fuel cost for the FCPP/thermal load, and hydrogen selling price are the main factors that affect the operational strategy. This paper presents a hybrid evolutionary programming and Hill-Climbing based approach to evaluate the impact of change of the above mentioned cost parameters on the optimal operational strategy of the FCPP. The optimal operational strategy of the FCPP for different tariffs is achieved through the estimation of the following: hourly generated power, the amount of thermal power recovered, power trade with the local grid, and the quantity of hydrogen that can be produced. Results show the importance of optimizing system cost parameters in order to minimize overall operating cost.

  17. Impact Assessment of Plug-in Hybrid Vehicles on the U.S. Power Grid

    SciTech Connect

    Kintner-Meyer, Michael CW; Nguyen, Tony B.; Jin, Chunlian; Balducci, Patrick J.; Secrest, Thomas J.

    2010-09-30

    The US electricity grid is a national infrastructure that has the potential to deliver significant amounts of the daily driving energy of the US light duty vehicle (cars, pickups, SUVs, and vans) fleet. This paper discusses a 2030 scenario with 37 million plug-in hybrid electric vehicles (PHEVs) on the road in the US demanding electricity for an average daily driving distance of about 33 miles (53 km). The paper addresses the potential grid impacts of the PHEVs fleet relative to their effects on the production cost of electricity, and the emissions from the electricity sector. The results of this analysis indicate significant regional difference on the cost impacts and the CO2 emissions. Battery charging during the day may have twice the cost impacts than charging during the night. The CO2 emissions impacts are very region-dependent. In predominantly coal regions (Midwest), the new PHEV load may reduce the CO2 emission intensity (ton/MWh), while in others regions with significant clean generation (hydro and renewable energy) the CO2 emission intensity may increase. Discussed will the potential impact of the results with the valuation of carbon emissions.

  18. A Vector Control for Grid-connected Wind Power Generation with Doubly Fed Induction Generator

    NASA Astrophysics Data System (ADS)

    Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

    Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation due to high efficiently for wind energy capture. An inverter system is required to control wind turbine speed and power factor in those generators. The inverter rating of the synchronous generator equals to generator rating. However, DFIG has the advantage that the inverter rating is about 25% to the generator rating. The paper describes a vector control of DFIG inter-connected to power line. The performance of proposed vector control is examined using power system simulation software PSCAD/EMTDC for the DFIG inter-connected to 6.6kv distribution line. The results show good dynamic responses and high accuracy to the stator active power control and the stator reactive power control.

  19. High-Power Zinc-Air Energy Storage: Enhanced Metal-Air Energy Storage System with Advanced Grid-Interoperable Power Electronics Enabling Scalability and Ultra-Low Cost

    SciTech Connect

    2010-10-01

    GRIDS Project: Fluidic is developing a low-cost, rechargeable, high-power module for Zinc-air batteries that will be used to store renewable energy. Zinc-air batteries are traditionally found in small, non-rechargeable devices like hearing aids because they are well-suited to delivering low levels of power for long periods of time. Historically, Zinc-air batteries have not been as useful for applications which require periodic bursts of power, like on the electrical grid. Fluidic hopes to fill this need by combining the high energy, low cost, and long run-time of a Zinc-air battery with new chemistry providing high power, high efficiency, and fast response. The battery module could allow large grid-storage batteries to provide much more power on very short demand—the most costly kind of power for utilities—and with much more versatile performance.

  20. A novel approach to smart grid technology for electrical power transmission lines by a self-organized optical network node based on optical bistability

    NASA Astrophysics Data System (ADS)

    Nakanishi, Soichiro; Sasaki, Wakao

    2011-01-01

    In this work, we have demonstrated a new smart grid model by our novel green photonics technology based on selforganized optical networks realizing an autonomous peer-to-peer electric power transmissions without centralized control for the power grid. In this optical network, we introduced an adaptive algorithm for concurrent peer-to-peer communications, by utilizing optical nonlinearity depending only on the signal strength passing through the network. This method is applicable for autonomous organization of functions for ad-hoc electric power distribution systems for the power grid. For this purpose, a simple optical- electrical hybrid bistable circuit composed of such as light emitting diode (LED) and photo diode (PD), has been incorporated into the network node. In the experiment, the method uses a simple, local adaptation of transmission weights at each network node, which enables self-organizing functions of the network, such as self-routing, self-optimization, self-recovery and self-protection. Based on this method, we have demonstrated experimentally a new smart grid model applicable for ad-hoc electric power distribution systems mediated by power comsumptions. In this model, electric power flow is controlled autonomously through the self-organized network nodes associated with individual power facilities having photovoltaics and electric storage devices, etc., and the nodes convert the amounts of electric power supply and/or comsumption to the light intensity values using above mentioned transmission weights at each node. As a consequence, we have experimentally demonstrated a simple shorthaul system model for ad-hoc electric power distribution with a self-organized optical network as a novel green photonics technology application for smart grid.

  1. Fuzzy Logic Based Controller for a Grid-Connected Solid Oxide Fuel Cell Power Plant.

    PubMed

    Chatterjee, Kalyan; Shankar, Ravi; Kumar, Amit

    2014-10-01

    This paper describes a mathematical model of a solid oxide fuel cell (SOFC) power plant integrated in a multimachine power system. The utilization factor of a fuel stack maintains steady state by tuning the fuel valve in the fuel processor at a rate proportional to a current drawn from the fuel stack. A suitable fuzzy logic control is used for the overall system, its objective being controlling the current drawn by the power conditioning unit and meet a desirable output power demand. The proposed control scheme is verified through computer simulations. PMID:25053926

  2. GridLAB-D/SG

    2011-08-30

    GridLAB-D is a new power system simulation tool that provides valuable information to users who design and operate electric power transmission and distribution systems, and to utilities that wish to take advantage of the latest smart grid technology. This special release of GridLAB-D was developed to study the proposed Smart Grid technology that is used by Battelle Memorial Institute in the AEP gridSMART demonstration project in Northeast Columbus, Ohio.

  3. Electrical Power Grid Delivery Dynamic Analysis: Using Prime Mover Engines to Balance Dynamic Wind Turbine Output

    SciTech Connect

    Diana K. Grauer; Michael E. Reed

    2011-11-01

    This paper presents an investigation into integrated wind + combustion engine high penetration electrical generation systems. Renewable generation systems are now a reality of electrical transmission. Unfortunately, many of these renewable energy supplies are stochastic and highly dynamic. Conversely, the existing national grid has been designed for steady state operation. The research team has developed an algorithm to investigate the feasibility and relative capability of a reciprocating internal combustion engine to directly integrate with wind generation in a tightly coupled Hybrid Energy System. Utilizing the Idaho National Laboratory developed Phoenix Model Integration Platform, the research team has coupled demand data with wind turbine generation data and the Aspen Custom Modeler reciprocating engine electrical generator model to investigate the capability of reciprocating engine electrical generation to balance stochastic renewable energy.

  4. Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

    SciTech Connect

    Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

    2014-10-24

    We explore optimization methods for planning the placement, sizing and operations of Flexible Alternating Current Transmission System (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to Series Compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of Linear Programs (LP) which are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPower Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed up that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically-sized networks that suffer congestion from a range of causes including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically-sized network.

  5. Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

    DOE PAGESBeta

    Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

    2014-10-24

    We explore optimization methods for planning the placement, sizing and operations of Flexible Alternating Current Transmission System (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to Series Compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of Linear Programs (LP) which are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPower Polishmore » Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed up that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically-sized networks that suffer congestion from a range of causes including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically-sized network.« less

  6. Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

    NASA Astrophysics Data System (ADS)

    Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

    2014-10-01

    We explore optimization methods for planning the placement, sizing and operations of flexible alternating current transmission system (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to series compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of linear programs (LP) that are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPower Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically sized networks that suffer congestion from a range of causes, including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically sized network.

  7. Securing smart grid technology

    NASA Astrophysics Data System (ADS)

    Chaitanya Krishna, E.; Kosaleswara Reddy, T.; Reddy, M. YogaTeja; Reddy G. M., Sreerama; Madhusudhan, E.; AlMuhteb, Sulaiman

    2013-03-01

    In the developing countries electrical energy is very important for its all-round improvement by saving thousands of dollars and investing them in other sector for development. For Growing needs of power existing hierarchical, centrally controlled grid of the 20th Century is not sufficient. To produce and utilize effective power supply for industries or people we should have Smarter Electrical grids that address the challenges of the existing power grid. The Smart grid can be considered as a modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure along with modern IT services, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability and so on. The main objective of this paper is to provide a contemporary look at the current state of the art in smart grid communications as well as critical issues on smart grid technologies primarily in terms of information and communication technology (ICT) issues like security, efficiency to communications layer field. In this paper we propose new model for security in Smart Grid Technology that contains Security Module(SM) along with DEM which will enhance security in Grid. It is expected that this paper will provide a better understanding of the technologies, potential advantages and research challenges of the smart grid and provoke interest among the research community to further explore this promising research area.

  8. Opportunities for ice storage to provide ancillary services to power grids incorporating wind turbine generation

    NASA Astrophysics Data System (ADS)

    Finley, Christopher

    Power generation using wind turbines increases the electrical system balancing, regulation and ramp rate requirements due to the minute to minute variability in wind speed and the difficulty in accurately forecasting wind speeds. The addition of thermal energy storage, such as ice storage, to a building's space cooling equipment increases the operational flexibility of the equipment by allowing the owner to choose when the chiller is run. The ability of the building owner to increase the power demand from the chiller (e.g. make ice) or to decrease the power demand (e.g. melt ice) to provide electrical system ancillary services was evaluated.

  9. Modeling and Control of VSC Based DC Connection for Active Stall Wind Farms to Grid

    NASA Astrophysics Data System (ADS)

    Iov, Florin; Sørensen, Poul; Hansen, Anca Daniela; Blaabjerg, Frede

    Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Therefore the power system becomes more vulnerable and dependent on the wind energy production. At the same time requirements that focus on the influence of the farms on the grid stability and power quality, and on the control capabilities of wind farms have already been established. The main trends of modern wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid does not have such control capabilities. They produce maximum possible power in continuous operation and are becoming disconnected in the case of a grid fault. Moreover, these wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection of the active stall wind farms to the grid can be a solution to these problems. Such a system has special regulating properties e.g. decoupled control of active and reactive power, continuous AC voltage regulation, variable frequency control, black-start capability, etc. This paper focuses on the modeling of such systems and proposes a control method of a voltage source converter based DC transmission system for connecting active stall wind farms to the grid.

  10. Impacts of Improved Day-Ahead Wind Forecasts on Power Grid Operations: September 2011

    SciTech Connect

    Piwko, R.; Jordan, G.

    2011-11-01

    This study analyzed the potential benefits of improving the accuracy (reducing the error) of day-ahead wind forecasts on power system operations, assuming that wind forecasts were used for day ahead security constrained unit commitment.

  11. Information Power Grid: Distributed High-Performance Computing and Large-Scale Data Management for Science and Engineering

    NASA Technical Reports Server (NTRS)

    Johnston, William E.; Gannon, Dennis; Nitzberg, Bill

    2000-01-01

    We use the term "Grid" to refer to distributed, high performance computing and data handling infrastructure that incorporates geographically and organizationally dispersed, heterogeneous resources that are persistent and supported. This infrastructure includes: (1) Tools for constructing collaborative, application oriented Problem Solving Environments / Frameworks (the primary user interfaces for Grids); (2) Programming environments, tools, and services providing various approaches for building applications that use aggregated computing and storage resources, and federated data sources; (3) Comprehensive and consistent set of location independent tools and services for accessing and managing dynamic collections of widely distributed resources: heterogeneous computing systems, storage systems, real-time data sources and instruments, human collaborators, and communications systems; (4) Operational infrastructure including management tools for distributed systems and distributed resources, user services, accounting and auditing, strong and location independent user authentication and authorization, and overall system security services The vision for NASA's Information Power Grid - a computing and data Grid - is that it will provide significant new capabilities to scientists and engineers by facilitating routine construction of information based problem solving environments / frameworks. Such Grids will knit together widely distributed computing, data, instrument, and human resources into just-in-time systems that can address complex and large-scale computing and data analysis problems. Examples of these problems include: (1) Coupled, multidisciplinary simulations too large for single systems (e.g., multi-component NPSS turbomachine simulation); (2) Use of widely distributed, federated data archives (e.g., simultaneous access to metrological, topological, aircraft performance, and flight path scheduling databases supporting a National Air Space Simulation systems}; (3

  12. A simple mathematical description of an off-grid hybrid solar-wind power generating system

    NASA Astrophysics Data System (ADS)

    Blasone, M.; Dell'Anno, F.; De Luca, R.; Torre, G.

    2013-05-01

    We give a detailed description of the energy balance equation for a stand-alone hybrid solar-wind power generating system. The dimensions of the power generator and the energy capacity of a buffer battery (used as an energy storage system) are chosen to suit a known consumer's profile. Future applications of the mathematical model developed and analogies with a similar hydrodynamic problem are discussed.

  13. Framework for Modeling High-Impact, Low-Frequency Power Grid Events to Support Risk-Informed Decisions

    SciTech Connect

    Veeramany, Arun; Unwin, Stephen D.; Coles, Garill A.; Dagle, Jeffery E.; Millard, W. David; Yao, Juan; Glantz, Clifford S.; Gourisetti, Sri Nikhil Gup

    2015-12-03

    Natural and man-made hazardous events resulting in loss of grid infrastructure assets challenge the electric power grid’s security and resilience. However, the planning and allocation of appropriate contingency resources for such events requires an understanding of their likelihood and the extent of their potential impact. Where these events are of low likelihood, a risk-informed perspective on planning can be problematic as there exists an insufficient statistical basis to directly estimate the probabilities and consequences of their occurrence. Since risk-informed decisions rely on such knowledge, a basis for modeling the risk associated with high-impact low frequency events (HILFs) is essential. Insights from such a model can inform where resources are most rationally and effectively expended. The present effort is focused on development of a HILF risk assessment framework. Such a framework is intended to provide the conceptual and overarching technical basis for the development of HILF risk models that can inform decision makers across numerous stakeholder sectors. The North American Electric Reliability Corporation (NERC) 2014 Standard TPL-001-4 considers severe events for transmission reliability planning, but does not address events of such severity that they have the potential to fail a substantial fraction of grid assets over a region, such as geomagnetic disturbances (GMD), extreme seismic events, and coordinated cyber-physical attacks. These are beyond current planning guidelines. As noted, the risks associated with such events cannot be statistically estimated based on historic experience; however, there does exist a stable of risk modeling techniques for rare events that have proven of value across a wide range of engineering application domains. There is an active and growing interest in evaluating the value of risk management techniques in the State transmission planning and emergency response communities, some of this interest in the context of

  14. Environmental and economic assessment of a cracked ammonia fuelled alkaline fuel cell for off-grid power applications

    NASA Astrophysics Data System (ADS)

    Cox, Brian; Treyer, Karin

    2015-02-01

    Global mobile telecommunication is possible due to millions of Base Transceiver Stations (BTS). Nearly 1 million of these are operating off-grid, typically powered by diesel generators and therefore leading to significant CO2 emissions and other environmental burdens. A novel type of Alkaline Fuel Cell (AFC) powered by cracked ammonia is being developed for replacement of these generators. This study compares the environmental and economic performance of the two systems by means of Life Cycle Assessment (LCA) and Levelised Cost of Electricity (LCOE), respectively. Results show that the production of ammonia dominates the LCA results, and that renewable ammonia production pathways greatly improve environmental performance. Sensitivity analyses reveal that the fuel cell parameters that most affect system cost and environmental burdens are cell power density and lifetime and system efficiency. Recycling of anode catalyst and electrode substrate materials is found to have large impacts on environmental performance, though without large cost incentives. For a set of target parameter values and fossil sourced ammonia, the AFC is calculated to produce electricity with life cycle CO2 eq emissions of 1.08 kg kWh-1, which is 23% lower than a diesel generator with electricity costs that are 14% higher in the same application.

  15. Optimal RTP Based Power Scheduling for Residential Load in Smart Grid

    NASA Astrophysics Data System (ADS)

    Joshi, Hemant I.; Pandya, Vivek J.

    2015-12-01

    To match supply and demand, shifting of load from peak period to off-peak period is one of the effective solutions. Presently flat rate tariff is used in major part of the world. This type of tariff doesn't give incentives to the customers if they use electrical energy during off-peak period. If real time pricing (RTP) tariff is used, consumers can be encouraged to use energy during off-peak period. Due to advancement in information and communication technology, two-way communications is possible between consumers and utility. To implement this technique in smart grid, home energy controller (HEC), smart meters, home area network (HAN) and communication link between consumers and utility are required. HEC interacts automatically by running an algorithm to find optimal energy consumption schedule for each consumer. However, all the consumers are not allowed to shift their load simultaneously during off-peak period to avoid rebound peak condition. Peak to average ratio (PAR) is considered while carrying out minimization problem. Linear programming problem (LPP) method is used for minimization. The simulation results of this work show the effectiveness of the minimization method adopted. The hardware work is in progress and the program based on the method described here will be made to solve real problem.

  16. Voltage controller/current limiter for ac

    NASA Technical Reports Server (NTRS)

    Wu, T. T.

    1980-01-01

    Circuit protects ac power systems for overload failures, limits power surge and short-circuit currents to 150 percent of steady state level, regulates ac output voltage, and soft starts loads. Limiter generates dc error signal in response to line fluctuations and dumps power when overload is reached. Device is inserted between ac source and load.

  17. New online voltage stability margins and risk assessment for multi-bus smart power grids

    NASA Astrophysics Data System (ADS)

    Aldeen, M.; Saha, S.; Alpcan, T.; Evans, R. J.

    2015-07-01

    This paper presents a quantitative framework for assessment of voltage stability in smart power networks. First, new stability indices similar to gain and phase margins in linear time invariant control systems are introduced. These indices can be computed online in conjunction with load-flow calculations. Then, a novel risk assessment framework incorporating the new stability indices is developed to methodologically quantify the voltage stability risks a power system faces at any given operating condition. In contrast to existing local stability indices and qualitative risk approaches, the indices and framework introduced provide analytical and quantitative evaluation of voltage stability and associated risks. The results are illustrated with a numerical example.

  18. Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

    NASA Astrophysics Data System (ADS)

    Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

    In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

  19. Assessing I-Grid(TM) web-based monitoring for power quality and reliability benchmarking

    SciTech Connect

    Divan, Deepak; Brumsickle, William; Eto, Joseph

    2003-04-30

    This paper presents preliminary findings from DOEs pilot program. The results show how a web-based monitoring system can form the basis for aggregation of data and correlation and benchmarking across broad geographical lines. A longer report describes additional findings from the pilot, including impacts of power quality and reliability on customers operations [Divan, Brumsickle, Eto 2003].

  20. Incorporation of wind generation to the Mexican power grid: Steady state analysis

    SciTech Connect

    Tovar, J.H.; Guardado, J.L.; Cisneros, F.; Cadenas, R.; Lopez, S.

    1997-09-01

    This paper describes a steady state analysis related with the incorporation of large amounts of eolic generation into the Mexican power system. An equivalent node is used to represent individual eolic generators in the wind farm. Possible overloads, losses, voltage and reactive profiles and estimated severe contingencies are analyzed. Finally, the conclusions of this study are presented.

  1. Implementing a Nuclear Power Plant Model for Evaluating Load-Following Capability on a Small Grid

    NASA Astrophysics Data System (ADS)

    Arda, Samet Egemen

    A pressurized water reactor (PWR) nuclear power plant (NPP) model is introduced into Positive Sequence Load Flow (PSLF) software by General Electric in order to evaluate the load-following capability of NPPs. The nuclear steam supply system (NSSS) consists of a reactor core, hot and cold legs, plenums, and a U-tube steam generator. The physical systems listed above are represented by mathematical models utilizing a state variable lumped parameter approach. A steady-state control program for the reactor, and simple turbine and governor models are also developed. Adequacy of the isolated reactor core, the isolated steam generator, and the complete PWR models are tested in Matlab/Simulink and dynamic responses are compared with the test results obtained from the H. B. Robinson NPP. Test results illustrate that the developed models represents the dynamic features of real-physical systems and are capable of predicting responses due to small perturbations of external reactivity and steam valve opening. Subsequently, the NSSS representation is incorporated into PSLF and coupled with built-in excitation system and generator models. Different simulation cases are run when sudden loss of generation occurs in a small power system which includes hydroelectric and natural gas power plants besides the developed PWR NPP. The conclusion is that the NPP can respond to a disturbance in the power system without exceeding any design and safety limits if appropriate operational conditions, such as achieving the NPP turbine control by adjusting the speed of the steam valve, are met. In other words, the NPP can participate in the control of system frequency and improve the overall power system performance.

  2. A NEW CROWBAR SYSTEM FOR THE PROTECTION OF HIGH POWER GRIDDED TUBES AND MICROWAVE DEVICES

    SciTech Connect

    S.G.E. PRONKO; T.E.HARRIS

    2001-04-01

    As part of the electron cyclotron heating (ECH) facility upgrade at the DIII-D National Fusion Facility, two 8.4 MW modulator/regulator power systems were designed and constructed (Ref. 1). Each power system uses a high power tetrode to modulate and regulate the cathode voltage for two 1 MW-class 110 GHz gyrotrons (Ref. 2). A critical element in the power system is the fault energy divertor, or crowbar switch, that protects the tetrode and the gyrotrons in the event of an arc fault. Traditionally, mercury filled ignitron switches are used for this application, but it was desired to eliminate hazardous materials and improve overall switching performance. The new crowbar switch system was required to meet the following requirements: Operating voltage: -105 kVdc; Peak current (750 ms e-fold): 1.6 kA; Follow-on current: <1 kA (25 ms); Charge transfer per shot: <15 Cb; and Turn-on time: <1 {micro}s. The switch that was chosen for the new design is a low pressure deuterium filled device, called a metal-arc thyratron, manufactured by Marconi Applied Technologies (Ref. 3). In addition to the new crowbar switch assembly, improved fault signal processing circuitry was developed. This new circuitry uses fiber-optics for signal and trigger transmission and a complex programmable logic device for high speed signal and logic processing. Two generations of metal-arc thyratrons have been commissioned in the two ECH power systems constructed at DIII-D. In the first, the crowbar system performed extremely well, meeting all of the operating requirements and demonstrating its ability to protect a 36 gauge copper wire from fusing (energy let-through <10 J). However, after accumulating over 500 shots, the metal-arc thyratrons lost their ability to reliably hold-off voltage. This problem was solved by Marconi with a design modification of the thyratron electrodes. The second generation tubes were installed in the second ECH power system. The crowbar system was fully commissioned and all

  3. AC Loss Measurements on a 2G YBCO Coil

    SciTech Connect

    Rey, Christopher M; Duckworth, Robert C; Schwenterly, S W

    2011-01-01

    The Oak Ridge National Laboratory (ORNL) is collaborating with Waukesha Electric Systems (WES) to continue development of HTS power transformers. For compatibility with the existing power grid, a commercially viable HTS transformer will have to operate at high voltages in the range of 138 kV and above, and will have to withstand 550-kV impulse voltages as well. Second-generation (2G) YBCO coated conductors will be required for an economically-competitive design. In order to adequately size the refrigeration system for these transformers, the ac loss of these HTS coils must be characterized. Electrical AC loss measurements were conducted on a prototype high voltage (HV) coil with co-wound stainless steel at 60 Hz in a liquid nitrogen bath using a lock-in amplifier technique. The prototype HV coil consisted of 26 continuous (without splice) single pancake coils concentrically centered on a stainless steel former. For ac loss measurement purposes, voltage tap pairs were soldered across each set of two single pancake coils so that a total of 13 separate voltage measurements could be made across the entire length of the coil. AC loss measurements were taken as a function of ac excitation current. Results show that the loss is primarily concentrated at the ends of the coil where the operating fraction of critical current is the highest and show a distinct difference in current scaling of the losses between low current and high current regimes.

  4. Integrating Renewable Electricity on the Grid

    NASA Astrophysics Data System (ADS)

    Crabtree, George; Misewich, Jim; Ambrosio, Ron; Clay, Kathryn; DeMartini, Paul; James, Revis; Lauby, Mark; Mohta, Vivek; Moura, John; Sauer, Peter; Slakey, Francis; Lieberman, Jodi; Tai, Humayun

    2011-11-01

    The demand for carbon-free electricity is driving a growing movement of adding renewable energy to the grid. Renewable Portfolio Standards mandated by states and under consideration by the federal government envision a penetration of 20-30% renewable energy in the grid by 2020 or 2030. The renewable energy potential of wind and solar far exceeds these targets, suggesting that renewable energy ultimately could grow well beyond these initial goals. The grid faces two new and fundamental technological challenges in accommodating renewables: location and variability. Renewable resources are concentrated at mid-continent far from population centers, requiring additional long distance, high-capacity transmission to match supply with demand. The variability of renewables due to the characteristics of weather is high, up to 70% for daytime solar due to passing clouds and 100% for wind on calm days, much larger than the relatively predictable uncertainty in load that the grid now accommodates by dispatching conventional resources in response to demand. Solutions to the challenges of remote location and variability of generation are needed. The options for DC transmission lines, favored over AC lines for transmission of more than a few hundred miles, need to be examined. Conventional high voltage DC transmission lines are a mature technology that can solve regional transmission needs covering one- or two-state areas. Conventional high voltage DC has drawbacks, however, of high loss, technically challenging and expensive conversion between AC and DC, and the requirement of a single point of origin and termination. Superconducting DC transmission lines lose little or no energy, produce no heat, and carry higher power density than conventional lines. They operate at moderate voltage, allowing many "on-ramps" and "off-ramps" in a single network and reduce the technical and cost challenges of AC to DC conversion. A network of superconducting DC cables overlaying the existing

  5. Large-scale data analysis of power grid resilience across multiple US service regions

    NASA Astrophysics Data System (ADS)

    Ji, Chuanyi; Wei, Yun; Mei, Henry; Calzada, Jorge; Carey, Matthew; Church, Steve; Hayes, Timothy; Nugent, Brian; Stella, Gregory; Wallace, Matthew; White, Joe; Wilcox, Robert

    2016-05-01

    Severe weather events frequently result in large-scale power failures, affecting millions of people for extended durations. However, the lack of comprehensive, detailed failure and recovery data has impeded large-scale resilience studies. Here, we analyse data from four major service regions representing Upstate New York during Super Storm Sandy and daily operations. Using non-stationary spatiotemporal random processes that relate infrastructural failures to recoveries and cost, our data analysis shows that local power failures have a disproportionally large non-local impact on people (that is, the top 20% of failures interrupted 84% of services to customers). A large number (89%) of small failures, represented by the bottom 34% of customers and commonplace devices, resulted in 56% of the total cost of 28 million customer interruption hours. Our study shows that extreme weather does not cause, but rather exacerbates, existing vulnerabilities, which are obscured in daily operations.

  6. Capturing Dynamics in the Power Grid: Formulation of Dynamic State Estimation through Data Assimilation

    SciTech Connect

    Zhou, Ning; Huang, Zhenyu; Meng, Da; Elbert, Stephen T.; Wang, Shaobu; Diao, Ruisheng

    2014-03-31

    With the increasing complexity resulting from uncertainties and stochastic variations introduced by intermittent renewable energy sources, responsive loads, mobile consumption of plug-in vehicles, and new market designs, more and more dynamic behaviors are observed in everyday power system operation. To operate a power system efficiently and reliably, it is critical to adopt a dynamic paradigm so that effective control actions can be taken in time. The dynamic paradigm needs to include three fundamental components: dynamic state estimation; look-ahead dynamic simulation; and dynamic contingency analysis (Figure 1). These three components answer three basic questions: where the system is; where the system is going; and how secure the system is against accidents. The dynamic state estimation provides a solid cornerstone to support the other 2 components and is the focus of this study.

  7. Utility-Scale Solar Power Converter: Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices

    SciTech Connect

    2012-01-25

    Solar ADEPT Project: Satcon is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels—eliminating the need for large transformers. Transformers “step up” the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually “stepped down” to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Satcon’s new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Satcon’s modular devices are designed to ensure reliability—if one device fails it can be bypassed and the system can continue to run.

  8. The interconnection of photovoltaic power systems with the utility grid: An overview for utility engineers

    SciTech Connect

    Wills, R.H.

    1994-06-01

    Utility-interactive (UI) photovoltaic power systems mounted on residences and commercial buildings are likely to become a small, but important source of electric generation in the next century. This is a new concept in utility power production--a change from large-scale central generation to small-scale dispersed generation. As such, it requires a re-examination of many existing standards and practices to enable the technology to develop and emerge into the marketplace. Much work has been done over the last 20 years to identify and solve the potential problems associated with dispersed power generation systems. This report gives an overview of these issues and also provides a guide to applicable codes, standards and other related documents. The main conclusion that can be drawn from this work is that there are no major technical barriers to the implementation of dispersed PV generating systems. While more technical research is needed in some specific areas, the remaining barriers are fundamentally price and policy.

  9. Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications.

    PubMed

    Khan, Farid Ullah

    2016-01-01

    For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters' wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented. PMID:27579343

  10. Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications

    PubMed Central

    2016-01-01

    For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters' wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented. PMID:27579343

  11. PowerGrid - A Computation Engine for Large-Scale Electric Networks

    SciTech Connect

    Chika Nwankpa

    2011-01-31

    This Final Report discusses work on an approach for analog emulation of large scale power systems using Analog Behavioral Models (ABMs) and analog devices in PSpice design environment. ABMs are models based on sets of mathematical equations or transfer functions describing the behavior of a circuit element or an analog building block. The ABM concept provides an efficient strategy for feasibility analysis, quick insight of developing top-down design methodology of large systems and model verification prior to full structural design and implementation. Analog emulation in this report uses an electric circuit equivalent of mathematical equations and scaled relationships that describe the states and behavior of a real power system to create its solution trajectory. The speed of analog solutions is as quick as the responses of the circuit itself. Emulation therefore is the representation of desired physical characteristics of a real life object using an electric circuit equivalent. The circuit equivalent has within it, the model of a real system as well as the method of solution. This report presents a methodology of the core computation through development of ABMs for generators, transmission lines and loads. Results of ABMs used for the case of 3, 6, and 14 bus power systems are presented and compared with industrial grade numerical simulators for validation.

  12. GRIDS: Grid-Scale Rampable Intermittent Dispatchable Storage

    SciTech Connect

    2010-09-01

    GRIDS Project: The 12 projects that comprise ARPA-E’s GRIDS Project, short for “Grid-Scale Rampable Intermittent Dispatchable Storage,” are developing storage technologies that can store renewable energy for use at any location on the grid at an investment cost less than $100 per kilowatt hour. Flexible, large-scale storage would create a stronger and more robust electric grid by enabling renewables to contribute to reliable power generation.

  13. Engineering the Implementation of Pumped Hydro Energy Storage in the Arizona Power Grid

    NASA Astrophysics Data System (ADS)

    Dixon, William Jesse J.

    This thesis addresses the issue of making an economic case for bulk energy storage in the Arizona bulk power system. Pumped hydro energy storage (PHES) is used in this study. Bulk energy storage has often been suggested for large scale electric power systems in order to levelize load (store energy when it is inexpensive [energy demand is low] and discharge energy when it is expensive [energy demand is high]). It also has the potential to provide opportunities to avoid transmission and generation expansion, and provide for generation reserve margins. As the level of renewable energy resources increases, the uncertainty and variability of wind and solar resources may be improved by bulk energy storage technologies. For this study, the MATLab software platform is used, a mathematical based modeling language, optimization solvers (specifically Gurobi), and a power flow solver (PowerWorld) are used to simulate an economic dispatch problem that includes energy storage and transmission losses. A program is created which utilizes quadratic programming to analyze various cases using a 2010 summer peak load from the Arizona portion of the Western Electricity Coordinating Council (WECC) system. Actual data from industry are used in this test bed. In this thesis, the full capabilities of Gurobi are not utilized (e.g., integer variables, binary variables). However, the formulation shown here does create a platform such that future, more sophisticated modeling may readily be incorporated. The developed software is used to assess the Arizona test bed with a low level of energy storage to study how the storage power limit effects several optimization outputs such as the system wide operating costs. Large levels of energy storage are then added to see how high level energy storage affects peak shaving, load factor, and other system applications. Finally, various constraint relaxations are made to analyze why the applications tested eventually approach a constant value. This

  14. System efficiency of a tap transformer based grid connection topology applied on a direct driven generator for wind power.

    PubMed

    Apelfröjd, Senad; Eriksson, Sandra

    2014-01-01

    Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed. PMID:25258733

  15. System Efficiency of a Tap Transformer Based Grid Connection Topology Applied on a Direct Driven Generator for Wind Power

    PubMed Central

    2014-01-01

    Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed. PMID:25258733

  16. Potential for Distributed and Central Electrolysis to Provide Grid Support Services (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    This NREL Hydrogen and Fuel Cell Technical Highlight describes how NREL operated both commercially available low-temperature electrolyzer technologies (PEM and alkaline) to evaluate their response to commands to increase and decrease stack power that shorten frequency disturbances on an alternating current (AC) mini-grid. Results show that both the PEM and alkaline electrolyzers are capable of adding or removing stack power to provide sub-second response that reduced the duration of frequency disturbances.

  17. Open-phase operating modes of power flow control topologies in a Smart Grid Distribution Network

    NASA Astrophysics Data System (ADS)

    Astashev, M. G.; Novikov, M. A.; Panfilov, D. I.; Rashitov, P. A.; Remizevich, T. V.; Fedorova, M. I.

    2015-12-01

    The power flow regulating circuit node in an alternating current system is reviewed. The circuit node is accomplished based on a thyristor controlled phase angle regulator (TCPAR) with controlled thyristor switch. Research results of the individual phase control of the output voltage for the TCPAR are presented. Analytical expressions for the overvoltage factor calculation in the thyristor switch circuit for open-phase operating modes are received. Based on evaluation of overvoltage in operational and emergency modes, the implementability conditions of the individual phase control of the output voltage are determined. Under these conditions, maximal performance and complete controllability are provided.

  18. Making the grid the backup: Utility applications for fuel cell power

    SciTech Connect

    Eklof, S.L.

    1996-12-31

    Fuel cells are recognized as a versatile power generation option and accepted component of SMUD`s ART Program. SMUD has received wide support and recognition for promoting and implementing fuel cell power plants, as well as other innovative generation, based primarily on technological factors. Current economic and technical realities in the electric generation market highlight other important factors, such as the cost involved to develop a slate of such resources. The goal now is to develop only those select quality resources most likely to become commercially viable in the near future. The challenge becomes the identification of candidate technologies with the greatest potential, and then matching the technologies with the applications that will help to make them successful. Utility participation in this development is critical so as to provide the industry with case examples of advanced technologies that can be applied in a way beneficial to both the utility and its customers. The ART resource acquisitions provide the experience base upon which to guide this selection process, and should bring about the cost reductions and reliability improvements sought.

  19. Green Power Grids: How Energy from Renewable Sources Affects Networks and Markets.

    PubMed

    Mureddu, Mario; Caldarelli, Guido; Chessa, Alessandro; Scala, Antonio; Damiano, Alfonso

    2015-01-01

    The increasing attention to environmental issues is forcing the implementation of novel energy models based on renewable sources. This is fundamentally changing the configuration of energy management and is introducing new problems that are only partly understood. In particular, renewable energies introduce fluctuations which cause an increased request for conventional energy sources to balance energy requests at short notice. In order to develop an effective usage of low-carbon sources, such fluctuations must be understood and tamed. In this paper we present a microscopic model for the description and for the forecast of short time fluctuations related to renewable sources in order to estimate their effects on the electricity market. To account for the inter-dependencies in the energy market and the physical power dispatch network, we use a statistical mechanics approach to sample stochastic perturbations in the power system and an agent based approach for the prediction of the market players' behavior. Our model is data-driven; it builds on one-day-ahead real market transactions in order to train agents' behaviour and allows us to deduce the market share of different energy sources. We benchmarked our approach on the Italian market, finding a good accordance with real data. PMID:26335705

  20. Green Power Grids: How Energy from Renewable Sources Affects Networks and Markets

    PubMed Central

    Mureddu, Mario; Caldarelli, Guido; Chessa, Alessandro; Scala, Antonio; Damiano, Alfonso

    2015-01-01

    The increasing attention to environmental issues is forcing the implementation of novel energy models based on renewable sources. This is fundamentally changing the configuration of energy management and is introducing new problems that are only partly understood. In particular, renewable energies introduce fluctuations which cause an increased request for conventional energy sources to balance energy requests at short notice. In order to develop an effective usage of low-carbon sources, such fluctuations must be understood and tamed. In this paper we present a microscopic model for the description and for the forecast of short time fluctuations related to renewable sources in order to estimate their effects on the electricity market. To account for the inter-dependencies in the energy market and the physical power dispatch network, we use a statistical mechanics approach to sample stochastic perturbations in the power system and an agent based approach for the prediction of the market players’ behavior. Our model is data-driven; it builds on one-day-ahead real market transactions in order to train agents’ behaviour and allows us to deduce the market share of different energy sources. We benchmarked our approach on the Italian market, finding a good accordance with real data. PMID:26335705

  1. Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

    PubMed

    Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

    2014-04-01

    Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system. PMID:24807951

  2. Wind Energy Management System EMS Integration Project: Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

    SciTech Connect

    Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

    2010-01-01

    unique features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. Currently, uncertainties associated with wind and load forecasts, as well as uncertainties associated with random generator outages and unexpected disconnection of supply lines, are not taken into account in power grid operation. Thus, operators have little means to weigh the likelihood and magnitude of upcoming events of power imbalance. In this project, funded by the U.S. Department of Energy (DOE), a framework has been developed for incorporating uncertainties associated with wind and load forecast errors, unpredicted ramps, and forced generation disconnections into the energy management system (EMS) as well as generation dispatch and commitment applications. A new approach to evaluate the uncertainty ranges for the required generation performance envelope including balancing capacity, ramping capability, and ramp duration has been proposed. The approach includes three stages: forecast and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence levels. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis, incorporating all sources of uncertainties of both continuous (wind and load forecast errors) and discrete (forced generator outages and start-up failures) nature. A new method called the “flying brick” technique has been developed to evaluate the look-ahead required generation performance envelope for the worst case scenario within a user-specified confidence level. A self-validation algorithm has been developed to validate the accuracy of the confidence intervals.

  3. Effect on the condition of the metal in A K-300-3.5 turbine owing to multicycle fatigue from participation of a power generating unit in grid frequency and power regulation

    SciTech Connect

    Lebedeva, A. I.; Zorchenko, N. V.; Prudnikov, A. A.

    2011-09-15

    The effect on the condition of the rotor material owing to multicycle fatigue caused by variable stresses during participation of a power generating unit in grid frequency and power regulation is evaluated using the K-300-23.5 steam turbine as an example. It is shown that during normalized primary frequency regulation the safety factor is at least 50, while during automatic secondary regulation of frequency and power there is essentially no damage to the metal.

  4. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  5. Operative and technological management of super-large united power grids: lessons of major world's blackouts

    NASA Astrophysics Data System (ADS)

    Brinkis, K.; Kreslins, V.; Mutule, A.

    2014-02-01

    Power system (PS) blackouts still persist worldwide, evidencing that the existing protective structures need to be improved. The discussed requirements and criteria to be met for joint synchronous operation of large and super-large united PSs should be based on close co-ordination of operative and technological management of all PSs involved in order to ensure secure and stable electricity supply and minimise or avoid the threat of a total PS blackout. The authors analyse the July 2012 India blackout - the largest power outage in history, which affected over 620 million people, i.e. half of India's population and spread across its 22 states. The analysis is of a general character, being applicable also to similar blackouts that have occurred in Europe and worldwide since 2003. The authors summarise and develop the main principles and methods of operative and technological management aimed at preventing total blackouts in large and super-large PSs. Neskatoties uz sasniegumiem elektroenerģētikas jomā un energosistēmu nepārtrauktu modernizāciju, pasaulē regulāri notiek sabrukumu avārijas. Rakstā apskatīti lielu un superlielu energosistēmu apvienību savstarpējas sinhronas darbības nodrošinājuma prasības un kritēriji, kas pamatojas uz operatīvās un tehnoloģiskās vadības ciešu koordināciju starp energosistēmām. Savstarpējas sinhronas darbības nodrošinājuma prasībām un kritērijiem ir izšķiroša nozīme, lai panāktu elektroapgādes drošumu un stabilitāti katrā energosistēmā, kas darbojas apvienotas energosistēmas sastāvā. Šo prasību un kritēriju ievērošana sekmē totālo avāriju izcelšanās iespēju samazināšanu un to novēršanu. Indijas 2012.gada totālo avāriju un citu analogo avāriju Eiropā un Amerikā analīze un izvērtējums laika posmā no 2003.gada, deva iespēju apkopot un izstrādāt lielu un superlielu energosistēmu operatīvās un tehnoloģiskās vadības principus un metodoloģiju, lai novērstu vai

  6. 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.

  7. Information Power Grid: Distributed High-Performance Computing and Large-Scale Data Management for Science and Engineering

    NASA Technical Reports Server (NTRS)

    Johnston, William E.; Gannon, Dennis; Nitzberg, Bill

    2000-01-01

    We use the term "Grid" to refer to distributed, high performance computing and data handling infrastructure that incorporates geographically and organizationally dispersed, heterogeneous resources that are persistent and supported. This infrastructure includes: (1) Tools for constructing collaborative, application oriented Problem Solving Environments / Frameworks (the primary user interfaces for Grids); (2) Programming environments, tools, and services providing various approaches for building applications that use aggregated computing and storage resources, and federated data sources; (3) Comprehensive and consistent set of location independent tools and services for accessing and managing dynamic collections of widely distributed resources: heterogeneous computing systems, storage systems, real-time data sources and instruments, human collaborators, and communications systems; (4) Operational infrastructure including management tools for distributed systems and distributed resources, user services, accounting and auditing, strong and location independent user authentication and authorization, and overall system security services The vision for NASA's Information Power Grid - a computing and data Grid - is that it will provide significant new capabilities to scientists and engineers by facilitating routine construction of information based problem solving environments / frameworks. Such Grids will knit together widely distributed computing, data, instrument, and human resources into just-in-time systems that can address complex and large-scale computing and data analysis problems. Examples of these problems include: (1) Coupled, multidisciplinary simulations too large for single systems (e.g., multi-component NPSS turbomachine simulation); (2) Use of widely distributed, federated data archives (e.g., simultaneous access to metrological, topological, aircraft performance, and flight path scheduling databases supporting a National Air Space Simulation systems}; (3

  8. Optimization and Analysis of High-Power Hydrogen/Bromine-Flow Batteries for Grid-Scale Energy Storage

    SciTech Connect

    Cho, KT; Albertus, P; Battaglia, V; Kojic, A; Srinivasan, V; Weber, AZ

    2013-10-07

    For storage of grid-scale electrical energy, redox-flow batteries (RFBs) are considered promising technologies. This paper explores the influence of electrolyte composition and ion transport on cell performance by using an integrated approach of experiments and cost modeling. In particular, the impact of the area-specific resistance on system capability is elucidated for the hydrogen/bromine RFB. The experimental data demonstrate very good performance with 1.46 W cm(-2) peak power and 4 A cm(-2) limiting current density at ambient conditions for an optimal cell design and reactant concentrations. The data and cost model results show that higher concentrations of RFB reactants do not necessarily result in lower capital cost as there is a tradeoff between cell performance and storage (tank) requirements. In addition, the discharge time and overall efficiency demonstrate nonlinear effects on system cost, with a 3 to 4 hour minimum discharge time showing a key transition to a plateau in terms of cost for typical RFB systems. The presented results are applicable to many different RFB chemistries and technologies and highlight the importance of ohmic effects and associated area-specific resistance on RFB viability.

  9. Multimode power processor

    DOEpatents

    O'Sullivan, George A.; O'Sullivan, Joseph A.

    1999-01-01

    In one embodiment, a power processor which operates in three modes: an inverter mode wherein power is delivered from a battery to an AC power grid or load; a battery charger mode wherein the battery is charged by a generator; and a parallel mode wherein the generator supplies power to the AC power grid or load in parallel with the battery. In the parallel mode, the system adapts to arbitrary non-linear loads. The power processor may operate on a per-phase basis wherein the load may be synthetically transferred from one phase to another by way of a bumpless transfer which causes no interruption of power to the load when transferring energy sources. Voltage transients and frequency transients delivered to the load when switching between the generator and battery sources are minimized, thereby providing an uninterruptible power supply. The power processor may be used as part of a hybrid electrical power source system which may contain, in one embodiment, a photovoltaic array, diesel engine, and battery power sources.

  10. Multimode power processor

    DOEpatents

    O'Sullivan, G.A.; O'Sullivan, J.A.

    1999-07-27

    In one embodiment, a power processor which operates in three modes: an inverter mode wherein power is delivered from a battery to an AC power grid or load; a battery charger mode wherein the battery is charged by a generator; and a parallel mode wherein the generator supplies power to the AC power grid or load in parallel with the battery. In the parallel mode, the system adapts to arbitrary non-linear loads. The power processor may operate on a per-phase basis wherein the load may be synthetically transferred from one phase to another by way of a bumpless transfer which causes no interruption of power to the load when transferring energy sources. Voltage transients and frequency transients delivered to the load when switching between the generator and battery sources are minimized, thereby providing an uninterruptible power supply. The power processor may be used as part of a hybrid electrical power source system which may contain, in one embodiment, a photovoltaic array, diesel engine, and battery power sources. 31 figs.

  11. Observer-based higher order sliding mode control of power factor in three-phase AC/DC converter for hybrid electric vehicle applications

    NASA Astrophysics Data System (ADS)

    Liu, Jianxing; Laghrouche, Salah; Wack, Maxime

    2014-06-01

    In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.

  12. Export of reactive nitrogen from coal-fired power plants in the U.S.: Estimates from a plume-in-grid modeling study - article no. D04308

    SciTech Connect

    Vijayaraghavan, K.; Zhang, Y.; Seigneur, C.; Karamchandani, P.; Snell, H.E.

    2009-02-15

    The export of reactive nitrogen (nitrogen oxides and their oxidation products, collectively referred to as NOy) from coal-fired power plants in the U.S. to the rest of the world could have a significant global contribution to ozone. Traditional Eulerian gridded air quality models cannot characterize accurately the chemistry and transport of plumes from elevated point sources such as power plant stacks. A state-of-the-science plume-in-grid (PinG) air quality model, a reactive plume model embedded in an Eulerian gridded model, is used to estimate the export of NOy from 25 large coal-fired power plants in the U. S. (in terms of NOx and SO{sub 2} emissions) in July 2001 to the global atmosphere. The PinG model used is the Community Multiscale Air Quality Model with Advanced Plume Treatment (CMAQ-APT). A benchmark simulation with only the gridded model, CMAQ, is also conducted for comparison purposes. The simulations with and without advanced plume treatment show differences in the calculated export of NOy from the 25 plants considered reflecting the effect of using a detailed and explicit treatment of plume transport and chemistry. The advanced plume treatment results in 31% greater simulated export of NOy compared to the purely grid-based modeling approach. The export efficiency of NOy (the fraction of NOy emitted that is exported) is predicted to be 21% without APT and 27% with APT. When considering only export through the eastern boundary across the Atlantic, CMAQ-APT predicts that the export efficiency is 24% and that 2% of NOy is exported as NOx, 49% as inorganic nitrate, and 25% as PAN. These results are in reasonably good agreement with an analysis reported in the literature of aircraft measurements over the North Atlantic.

  13. A grid amplifier

    NASA Technical Reports Server (NTRS)

    Kim, Moonil; Weikle, Robert M., II; Hacker, Jonathan B.; Delisio, Michael P.; Rutledge, David B.; Rosenberg, James J.; Smith, R. P.

    1991-01-01

    A 50-MESFET grid amplifier is reported that has a gain of 11 dB at 3.3 GHz. The grid isolates the input from the output by using vertical polarization for the input beam and horizontal polarization for the transmitted output beam. The grid unit cell is a two-MESFET differential amplifier. A simple calibration procedure allows the gain to be calculated from a relative power measurement. This grid is a hybrid circuit, but the structure is suitable for fabrication as a monolithic wafer-scale integrated circuit, particularly at millimeter wavelengths.

  14. Numerical simulation of a powered-lift landing, tracking flow features using overset grids, and simulation of high lift devices on a fighter-lift-and-control wing

    NASA Technical Reports Server (NTRS)

    Chawla, Kalpana

    1993-01-01

    Attached as appendices to this report are documents describing work performed on the simulation of a landing powered-lift delta wing, the tracking of flow features using overset grids, and the simulation of flaps on the Wright Patterson Lab's fighter-lift-and-control (FLAC) wing. Numerical simulation of a powered-lift landing includes the computation of flow about a delta wing at four fixed heights as well as a simulated landing, in which the delta wing descends toward the ground. Comparison of computed and experimental lift coefficients indicates that the simulations capture the qualitative trends in lift-loss encountered by thrust-vectoring aircraft operating in ground effect. Power spectra of temporal variations of pressure indicate computed vortex shedding frequencies close to the jet exit are in the experimentally observed frequency range; the power spectra of pressure also provide insights into the mechanisms of lift oscillations. Also, a method for using overset grids to track dynamic flow features is described and the method is validated by tracking a moving shock and vortices shed behind a circular cylinder. Finally, Chimera gridding strategies were used to develop pressure coefficient contours for the FLAC wing for a Mach no. of 0.18 and Reynolds no. of 2.5 million.

  15. Development of V2G and G2V Power Profiles and Their Implications on Grid Under Varying Equilibrium of Aggregated Electric Vehicles

    NASA Astrophysics Data System (ADS)

    Jain, Prateek; Jain, Trapti

    2016-04-01

    The objective of this paper is to examine the vehicle-to-grid (V2G) power capability of aggregated electric vehicles (EV) in the manner that they are being adopted by the consumers with their growing infiltration in the vehicles market. The proposed modeling of V2G and grid-to-vehicle (G2V) energy profiles blends the heterogeneous attributes namely, driven mileages, arrival and departure times, travel and parking durations, and speed dependent energy consumption of mobility trends. Three penetration percentages of 25 %, 50 % and 100 % resulting in varied compositions of battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) in the system, as determined by the consumers' acceptance, have been considered to evaluate the grid capacity for V2G. Distinct charge-discharge powers have been selected as per charging standards to match contemporary vehicles and infrastructure requirements. Charging and discharging approaches have been devised to replicate non-linear characteristics of Li-ion battery. Effects of simultaneous conjunction of V2G and G2V power curves with daily conventional load profile are quantified drawn upon workplace-discharging home-charging scheme. Results demonstrated a marked drop in load and hence in market price during morning hours which is hurriedly overcompensated by the hike during evening hours with rising penetration level and charge-discharge power.

  16. Evaluation of a binary optimization approach to find the optimum locations of energy storage devices in a power grid with stochastically varying loads and wind generation

    NASA Astrophysics Data System (ADS)

    Dar, Zamiyad

    The prices in the electricity market change every five minutes. The prices in peak demand hours can be four or five times more than the prices in normal off peak hours. Renewable energy such as wind power has zero marginal cost and a large percentage of wind energy in a power grid can reduce the price significantly. The variability of wind power prevents it from being constantly available in peak hours. The price differentials between off-peak and on-peak hours due to wind power variations provide an opportunity for a storage device owner to buy energy at a low price and sell it in high price hours. In a large and complex power grid, there are many locations for installation of a storage device. Storage device owners prefer to install their device at locations that allow them to maximize profit. Market participants do not possess much information about the system operator's dispatch, power grid, competing generators and transmission system. The publicly available data from the system operator usually consists of Locational Marginal Prices (LMP), load, reserve prices and regulation prices. In this thesis, we develop a method to find the optimum location of a storage device without using the grid, transmission or generator data. We formulate and solve an optimization problem to find the most profitable location for a storage device using only the publicly available market pricing data such as LMPs, and reserve prices. We consider constraints arising due to storage device operation limitations in our objective function. We use binary optimization and branch and bound method to optimize the operation of a storage device at a given location to earn maximum profit. We use two different versions of our method and optimize the profitability of a storage unit at each location in a 36 bus model of north eastern United States and south eastern Canada for four representative days representing four seasons in a year. Finally, we compare our results from the two versions of our

  17. SU-E-J-102: Separation of Metabolic Supply and Demand: From Power Grid Economics to Cancer Metabolism

    SciTech Connect

    Epstein, T; Xu, L; Gillies, R; Gatenby, R

    2014-06-01

    Purpose: To study a new model of glucose metabolism which is primarily governed by the timescale of the energetic demand and not by the oxygen level, and its implication on cancer metabolism (Warburg effect) Methods: 1) Metabolic profiling of membrane transporters activity in several cell lines, which represent the spectrum from normal breast epithelium to aggressive, metastatic cancer, using Seahorse XF reader.2) Spatial localization of oxidative and non-oxidative metabolic components using immunocytochemical imaging of the glycolytic ATP-producing enzyme, pyruvate kinase and mitochondria. 3) Finite element simulations of coupled partial differential equations using COMSOL and MATLAB. Results: Inhibition or activation of pumps on the cell membrane led to reduction or increase in aerobic glycolysis, respectively, while oxidative phosphorylation remained unchanged. These results were consistent with computational simulations of changes in short-timescale demand for energy by cell membrane processes. A specific model prediction was that the spatial distribution of ATP-producing enzymes in the glycolytic pathway must be primarily localized adjacent to the cell membrane, while mitochondria should be predominantly peri-nuclear. These predictions were confirmed experimentally. Conclusion: The results in this work support a new model for glucose metabolism in which glycolysis and oxidative phosphorylation supply different types of energy demand. Similar to power grid economics, optimal metabolic control requires the two pathways, even in normoxic conditions, to match two different types of energy demands. Cells use aerobic metabolism to meet baseline, steady energy demand and glycolytic metabolism to meet short-timescale energy demands, mainly from membrane transport activities, even in the presence of oxygen. This model provides a mechanism for the origin of the Warburg effect in cancer cells. Here, the Warburg effect emerges during carcinogenesis is a physiological

  18. Final report for %22High performance computing for advanced national electric power grid modeling and integration of solar generation resources%22, LDRD Project No. 149016.

    SciTech Connect

    Reno, Matthew J.; Riehm, Andrew Charles; Hoekstra, Robert John; Munoz-Ramirez, Karina; Stamp, Jason Edwin; Phillips, Laurence R.; Adams, Brian M.; Russo, Thomas V.; Oldfield, Ron A.; McLendon, William Clarence, III; Nelson, Jeffrey Scott; Hansen, Clifford W.; Richardson, Bryan T.; Stein, Joshua S.; Schoenwald, David Alan; Wolfenbarger, Paul R.

    2011-02-01

    Design and operation of the electric power grid (EPG) relies heavily on computational models. High-fidelity, full-order models are used to study transient phenomena on only a small part of the network. Reduced-order dynamic and power flow models are used when analysis involving thousands of nodes are required due to the computational demands when simulating large numbers of nodes. The level of complexity of the future EPG will dramatically increase due to large-scale deployment of variable renewable generation, active load and distributed generation resources, adaptive protection and control systems, and price-responsive demand. High-fidelity modeling of this future grid will require significant advances in coupled, multi-scale tools and their use on high performance computing (HPC) platforms. This LDRD report demonstrates SNL's capability to apply HPC resources to these 3 tasks: (1) High-fidelity, large-scale modeling of power system dynamics; (2) Statistical assessment of grid security via Monte-Carlo simulations of cyber attacks; and (3) Development of models to predict variability of solar resources at locations where little or no ground-based measurements are available.

  19. Utility-Scale Silicon Carbide Power Transistors: 15 kV SiC IGBT Power Modules for Grid Scale Power Conversion

    SciTech Connect

    2010-09-01

    ADEPT Project: Cree is developing silicon carbide (SiC) power transistors that are 50% more energy efficient than traditional transistors. Transistors act like a switch, controlling the electrical energy that flows through an electrical circuit. Most power transistors today use silicon semiconductors to conduct electricity. However, transistors with SiC semiconductors operate at much higher temperatures, as well as higher voltage and power levels than their silicon counterparts. SiC-based transistors are also smaller and require less cooling than those made with traditional silicon power technology. Cree's SiC transistors will enable electrical circuits to handle higher power levels more efficiently, and they will result in much smaller and lighter electrical devices and power converters. Cree, an established leader in SiC technology, has already released a commercially available SiC transistor that can operate at up to 1,200 volts. The company has also demonstrated a utility-scale SiC transistor that operates at up to 15,000 volts.

  20. 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.

  1. Scaling Up Renewable Energy Generation: Aligning Targets and Incentives with Grid Integration Considerations, Greening The Grid

    SciTech Connect

    Katz, Jessica; Cochran, Jaquelin

    2015-05-27

    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. This document, part of a Greening the Grid toolkit, provides power system planners with tips to help secure and sustain investment in new renewable energy generation by aligning renewable energy policy targets and incentives with grid integration considerations.

  2. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  3. Ion Engine Grid Gap Measurements

    NASA Technical Reports Server (NTRS)

    Soulas, Gerge C.; Frandina, Michael M.

    2004-01-01

    A simple technique for measuring the grid gap of an ion engine s ion optics during startup and steady-state operation was demonstrated with beam extraction. The grid gap at the center of the ion optics assembly was measured with a long distance microscope that was focused onto an alumina pin that protruded through the center accelerator grid aperture and was mechanically attached to the screen grid. This measurement technique was successfully applied to a 30 cm titanium ion optics assembly mounted onto an NSTAR engineering model ion engine. The grid gap and each grid s movement during startup from room temperature to both full and low power were measured. The grid gaps with and without beam extraction were found to be significantly different. The grid gaps at the ion optics center were both significantly smaller than the cold grid gap and different at the two power levels examined. To avoid issues associated with a small grid gap during thruster startup with titanium ion optics, a simple method was to operate the thruster initially without beam extraction to heat the ion optics. Another possible method is to apply high voltage to the grids prior to igniting the discharge because power deposition to the grids from the plasma is lower with beam extraction than without. Further testing would be required to confirm this approach.

  4. Decentral Smart Grid Control

    NASA Astrophysics Data System (ADS)

    Schäfer, Benjamin; Matthiae, Moritz; Timme, Marc; Witthaut, Dirk

    2015-01-01

    Stable operation of complex flow and transportation networks requires balanced supply and demand. For the operation of electric power grids—due to their increasing fraction of renewable energy sources—a pressing challenge is to fit the fluctuations in decentralized supply to the distributed and temporally varying demands. To achieve this goal, common smart grid concepts suggest to collect consumer demand data, centrally evaluate them given current supply and send price information back to customers for them to decide about usage. Besides restrictions regarding cyber security, privacy protection and large required investments, it remains unclear how such central smart grid options guarantee overall stability. Here we propose a Decentral Smart Grid Control, where the price is directly linked to the local grid frequency at each customer. The grid frequency provides all necessary information about the current power balance such that it is sufficient to match supply and demand without the need for a centralized IT infrastructure. We analyze the performance and the dynamical stability of the power grid with such a control system. Our results suggest that the proposed Decentral Smart Grid Control is feasible independent of effective measurement delays, if frequencies are averaged over sufficiently large time intervals.

  5. Wind Energy Management System Integration Project Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

    SciTech Connect

    Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

    2010-09-01

    features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. In this report, a new methodology to predict the uncertainty ranges for the required balancing capacity, ramping capability and ramp duration is presented. Uncertainties created by system load forecast errors, wind and solar forecast errors, generation forced outages are taken into account. The uncertainty ranges are evaluated for different confidence levels of having the actual generation requirements within the corresponding limits. The methodology helps to identify system balancing reserve requirement based on a desired system performance levels, identify system “breaking points”, where the generation system becomes unable to follow the generation requirement curve with the user-specified probability level, and determine the time remaining to these potential events. The approach includes three stages: statistical and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence intervals. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis incorporating all sources of uncertainty and parameters of a continuous (wind forecast and load forecast errors) and discrete (forced generator outages and failures to start up) nature. Preliminary simulations using California Independent System Operator (California ISO) real life data have shown the effectiveness of the proposed approach. A tool developed based on the new methodology described in this report will be integrated with the California ISO systems. Contractual work is currently in place to integrate the tool with the AREVA EMS system.

  6. A framework to identify Pareto-efficient subdaily environmental flow constraints on hydropower reservoirs using a grid-wide power dispatch model

    NASA Astrophysics Data System (ADS)

    Olivares, Marcelo A.; Haas, Jannik; Palma-Behnke, Rodrigo; Benavides, Carlos

    2015-05-01

    Hydrologic alteration due to hydropeaking reservoir operations is a main concern worldwide. Subdaily environmental flow constraints (ECs) on operations can be promising alternatives for mitigating negative impacts. However, those constraints reduce the flexibility of hydropower plants, potentially with higher costs for the power system. To study the economic and environmental efficiency of ECs, this work proposes a novel framework comprising four steps: (i) assessment of the current subdaily hydrologic alteration; (ii) formulation and implementation of a short-term, grid-wide hydrothermal coordination model; (iii) design of ECs in the form of maximum ramping rates (MRRs) and minimum flows (MIFs) for selected hydropower reservoirs; and (iv) identification of Pareto-efficient solutions in terms of grid-wide costs and the Richard-Baker flashiness index for subdaily hydrologic alteration (SDHA). The framework was applied to Chile's main power grid, assessing 25 EC cases, involving five MIFs and five MRRs. Each case was run for a dry, normal, and wet water year type. Three Pareto-efficient ECs are found, with remarkably small cost increase below 2% and a SDHA improvement between 28% and 90%. While the case involving the highest MIF worsens the flashiness of another basin, the other two have no negative effect on other basins and can be recommended for implementation.

  7. Grid pulser for an electron gun with a thermionic cathode for the high-power operation of a terahertz free-electron laser

    NASA Astrophysics Data System (ADS)

    Suemine, Shoji; Kawase, Keigo; Sugimoto, Naoya; Kashiwagi, Shigeru; Furukawa, Kazuya; Kato, Ryukou; Irizawa, Akinori; Fujimoto, Masaki; Ohsumi, Hiroki; Yaguchi, Masaki; Funakoshi, Sousuke; Tsutsumi, Ryouta; Kubo, Kumiko; Tokuchi, Akira; Isoyama, Goro

    2015-02-01

    A grid pulser for a thermionic-cathode electron gun for an L-band electron linac with an RF frequency of 1.3 GHz was developed in an effort to increase the power of a terahertz (THz) free-electron laser (FEL) based on the linac. The grid pulser can generate a train of electron pulses with a 5-ns duration at intervals of 36.9 ns or at a repetition frequency of 27 MHz, which is the 48th sub-harmonic of the RF frequency, and with a peak current of up to 2.4 A or higher, which is four times higher than the current that can be obtained with the conventional grid pulser. In combination with the sub-harmonic buncher (SHB) system, whose fundamental frequency is 108 MHz (the 12th sub-harmonic of the RF frequency), an electron beam that comprises electron bunches separated by 36.9-ns intervals for a period of 8 μs can be successfully accelerated using the linac to an energy of 15 MeV under the condition that the average beam current or, correspondingly, the beam loading in the acceleration tube of the linac is the same as that obtained using the conventional grid pulser. The time-resolved energy spectrum indicates that the energy is constant over the latter 6 μs and that the energy spread is 1.2% (FWHM); this performance satisfies the requirements for the FEL. The bunch charge measured at the end of the FEL beamline is 4 nC, which is four times higher than that obtained using the conventional grid pulser.

  8. 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.

  9. Spatial evolution of the helical behavior and the 2/3 power-law in single-square-grid-generated turbulence

    NASA Astrophysics Data System (ADS)

    Zhou, Yi; Nagata, Kouji; Sakai, Yasuhiko; Ito, Yasumasa; Hayase, Toshiyuki

    2016-04-01

    Direct numerical simulations are performed to investigate the helical properties of single-square-grid-generated turbulence. The streamwise evolution of the probability density functions of the relative helicity density h reveals the existence of a transition from a quasi-two-dimensional state to a three-dimensional state. The correlations between the helicity and the enstrophy level as well as the dissipation level are examined. When conditioned on a high level of dissipation or enstrophy, in the energy decay region the velocity and vorticity vectors in both instantaneous and fluctuating fields become more aligned. However, this correlation does not hold in the production region. We also study the second-order structure function and reveal that a well-defined 2/3 power-law can be found at a location quite close to the grid, where the turbulent flow is still in the transition state.

  10. Composite rod insulators for ac power lines; Electrical performance of various designs at a coastal testing station

    SciTech Connect

    Houlgate, R.G.; Swift, D.A. )

    1990-10-01

    The electrical performance of thirty-six composite insulators - of four commercial types for each AC system level of 34.5 kV, 230 kV and 500 kV - has been determined at the CEGB insulator testing station, Brighton, England. The weathershed materials were epoxy-resin, ethylene propylene rubber and silicone rubber; half of the 230 kV insulators had no stress rings. Surface leakage current was recorded for surge levels of 25 mA, 150 mA and 500 mA; a special technique was developed to obtain the flashover statistics of the 500 kV insulators, thereby enabling performance of the composite insulator to be quantified relative to that of a string of cap and pin porcelain insulators of anti-fog design, the deterioration of the insulators was observed by making regular visual inspections. The practical consequences of the findings and the causes of the degradation are discussed.

  11. Wireless transmission of power and information through one high-frequency resonant AC link inverter for robot manipulator applications

    SciTech Connect

    Kawamura, Atsuo; Ishioka, K.; Hirai, J.

    1996-05-01

    A contactless decentralized power supply is proposed with communication capability through only one transformer. A prototype of wireless transmission system of power and information (WTPI system) was built, and the two-axis position controls of servo motors were achieved by transferring the power and signal through one rotatable high-frequency transformer. The proposed concept can be applied for robotics and numerical control (NC) machines.

  12. HTS DC Transmission Line for Megalopolis Grid Development

    NASA Astrophysics Data System (ADS)

    Kopylov, S.; Sytnikov, V.; Bemert, S.; Ivanov, Yu; Krivetskiy, I.; Romashov, M.; Shakaryan, Yu; Keilin, V.; Shikov, A.; Patrikeev, V.; Lobyntsev, V.; Shcherbakov, V.

    2014-05-01

    Using of HTS AC and DC cables in electric power grids allows increasing of the transferred power, losses diminishing, decreasing of exclusion zone areas, the enhancement of the environmental conditions and fire/explosion safety of electric power systems. However, the use of DC superconducting cable lines together with converters brings additional advantages as reduction of losses in cables and suitable lowering of refrigerating plant capacity, as well as the realization of the function of short-circuit currents limitation by means of the appropriate setting of converter equipment. Russian Federal Grid Company and its R&D Center started the construction of the DC HTS power transmission line which includes the cable itself, cryogenic equipment, AC/DC converters, terminals and cable coupling boxes. This line will connect two substations in Saint-Petersburg - 330 kV "Centralnaya" and 220 kV "RP-9". The length of this HTS transmission line will be about 2500 meters. Nowadays are developed all the elements of the line and technologies of the cable manufacturing. Two HTS cable samples, each 30 m length, have been made. This paper describes the results of cables tests.

  13. 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.

  14. Hall-effect based semi-fast AC on-board charging equipment for electric vehicles.

    PubMed

    Milanés-Montero, María Isabel; Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; González-Romera, Eva

    2011-01-01

    The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented. PMID:22163697

  15. Hall-Effect Based Semi-Fast AC On-Board Charging Equipment for Electric Vehicles

    PubMed Central

    Milanés-Montero, María Isabel; Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; González-Romera, Eva

    2011-01-01

    The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented. PMID:22163697

  16. Scaling law and general expression for transport ac loss of a rectangular thin strip with power-law E(J) relation

    NASA Astrophysics Data System (ADS)

    Chen, Du-Xing; Li, Shuo; Fang, Jin

    2015-12-01

    Transport ac loss Q of a superconducting rectangular thin strip obeying a power-law relation E∝Jn as a function of current amplitude Im may be, following Norris, expressed by normalized quantities as q(im). A scaling law is deduced that if Icf, Ic and f being the critical current and frequency, is multiplied by a positive constant C, then im and qm are multiplied by C 1 /(n - 1)and C 2 /(n - 1) , respectively. Based on this scaling law and the well-known Norris formula, the general function of q(im, n, f) is obtained graphically or analytically for any practical purpose, after accurate numerical computations on a set of q(im) at several values of n and a fixed value of f.

  17. Grid-Optimization Program for Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Daniel, R. E.; Lee, T. S.

    1986-01-01

    CELLOPT program developed to assist in designing grid pattern of current-conducting material on photovoltaic cell. Analyzes parasitic resistance losses and shadow loss associated with metallized grid pattern on both round and rectangular solar cells. Though performs sensitivity studies, used primarily to optimize grid design in terms of bus bar and grid lines by minimizing power loss. CELLOPT written in APL.

  18. 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.

  19. Power Delivery from an Actual Thermoelectric Generation System

    NASA Astrophysics Data System (ADS)

    Kaibe, Hiromasa; Kajihara, Takeshi; Nagano, Kouji; Makino, Kazuya; Hachiuma, Hirokuni; Natsuume, Daisuke

    2014-06-01

    Similar to photovoltaic (PV) and fuel cells, thermoelectric generators (TEGs) supply direct-current (DC) power, essentially requiring DC/alternating current (AC) conversion for delivery as electricity into the grid network. Use of PVs is already well established through power conditioning systems (PCSs) that enable DC/AC conversion with maximum-power-point tracking, which enables commercial use by customers. From the economic, legal, and regulatory perspectives, a commercial PCS for PVs should also be available for TEGs, preferably as is or with just simple adjustment. Herein, we report use of a PV PCS with an actual TEG. The results are analyzed, and proper application for TEGs is proposed.

  20. Scalable Real Time Data Management for Smart Grid

    SciTech Connect

    Yin, Jian; Kulkarni, Anand V.; Purohit, Sumit; Gorton, Ian; Akyol, Bora A.

    2011-12-16

    This paper presents GridMW, a scalable and reliable data middleware for smart grids. Smart grids promise to improve the efficiency of power grid systems and reduce green house emissions through incorporating power generation from renewable sources and shaping demand to match the supply. As a result, power grid systems will become much more dynamic and require constant adjustments, which requires analysis and decision making applications to improve the efficiency and reliability of smart grid systems.