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1

High-frequency ac power distribution in Space Station  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

2

Characterization and analysis of electromagnetic interference in a high frequency AC distributed power system  

Microsoft Academic Search

High frequency quasi-square AC distributed power systems simplify the complexity of DC distributed power systems at the expense of greater generated EMI due to high values of dV\\/dt and dI\\/dt displayed in the bus waveform characteristics. To quantify EMI effects, the bus structure of a 300 kHz quasi-square waveform AC distributed power system is analyzed using the partial element equivalent

Michael T. Zhang; R. Watson; F. C. Lee; J. Roudet; J.-L. Schanen; E. Clavel

1996-01-01

3

Power conversion distribution system using a resonant high-frequency AC link  

NASA Technical Reports Server (NTRS)

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.

Sood, P. K.; Lipo, T. A.

1986-01-01

4

Phasor-Domain Modeling of Resonant Inverters for High-Frequency AC Power Distribution Systems  

Microsoft Academic Search

The circuit modeling and analysis of resonant inverters is complex because the state variables such as inductor currents and capacitor voltages are AC dominant. The phasor dynamic modeling method maps the periodical time-varying state variables into stationary frame for each harmonic of interest. Correspondingly, the circuit is decomposed into two DC subcircuits, the state variables of which are the time-varying

Zhongming Ye; Praveen K. Jain; Paresh C. Sen

2009-01-01

5

A Novel AC Uninterruptible Power Supply  

Microsoft Academic Search

This paper introduces a new ac Uninterruptible Power Supply (UPS) that has high efficiency, ac-input voltage regulation, and continuity of output power during any type of commercial ac-input power disturbance. These features are achieved in this UPS without the ac line-frequency energy storage components utilized in other UPSs to maintain output continuity during an ac-input power failure.

Farhad Barzegar; Michael J. Model

1987-01-01

6

AC power system breadboard  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

7

Design and analysis of modern three-phase AC/AC power converters for AC drives and utility interface  

E-print Network

Significant advances in modern ac/ac power converter technologies and demands of industries have reached beyond standard ac/ac power converters with voltage-source inverters fed from diode rectifiers. Power electronics converters have been matured...

Kwak, Sangshin

2005-08-29

8

21 CFR 880.5500 - AC-powered patient lift.  

...2014-04-01 2014-04-01 false AC-powered patient lift. 880.5500 Section 880...Therapeutic Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered...

2014-04-01

9

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false AC-powered patient lift. 880.5500 Section 880...Therapeutic Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered...

2011-04-01

10

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false AC-powered patient lift. 880.5500 Section 880...Therapeutic Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered...

2012-04-01

11

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false AC-powered patient lift. 880.5500 Section 880...Therapeutic Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered...

2013-04-01

12

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880...Therapeutic Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered...

2010-04-01

13

21 CFR 886.1850 - AC-powered slitlamp biomicroscope.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false AC-powered slitlamp biomicroscope. 886.1850...Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an...

2013-04-01

14

21 CFR 886.1850 - AC-powered slitlamp biomicroscope.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false AC-powered slitlamp biomicroscope. 886.1850...Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an...

2011-04-01

15

21 CFR 886.1850 - AC-powered slitlamp biomicroscope.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false AC-powered slitlamp biomicroscope. 886.1850...Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an...

2012-04-01

16

21 CFR 886.1850 - AC-powered slitlamp biomicroscope.  

...2014-04-01 2014-04-01 false AC-powered slitlamp biomicroscope. 886.1850...Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an...

2014-04-01

17

High frequency AC power converter for low voltage circuits  

E-print Network

This thesis presents a novel AC power delivery architecture that is suitable for VHF frequency (50-100MHz) polyphase AC/DC power conversion in low voltage integrated circuits. A complete AC power delivery architecture was ...

Salazar, Nathaniel Jay Tobias

2012-01-01

18

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food...Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that...

2011-04-01

19

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food...Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that...

2013-04-01

20

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food...Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that...

2012-04-01

21

21 CFR 886.4440 - AC-powered magnet.  

...2014-04-01 2014-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food...Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that...

2014-04-01

22

Wide band AC power line characterization  

Microsoft Academic Search

This paper presents data characterizing the household AC power line in the 1-60 MHz band. Two types of measurements were performed: transmission and noise sampling. The transmission measurements were done by using the impulse channel sounding method, so both the line attenuation and the delay spread were obtained. The noise measurements include: power line background noise, appliance noise, and noise

D. Liu; E. Flint; B. Gaucher; Y. Kwark

1999-01-01

23

Active power filter for nonlinear AC loads  

Microsoft Academic Search

This paper describes an active power filter for nonlinear AC loads with the power part carried out in the bridge connection. A theoretical approach to the implementation of the current reference is given for this original solution of the serial active filter. The paper also provides experimental results of the filter application on two specific nonlinear loads, i.e., on the

J. Nastran; R. Cajhen; M. Seliger; P. Jereb

1994-01-01

24

A series compensator based on AC-AC power converters with virtual quadrature modulation  

Microsoft Academic Search

This paper presents a new topology of a three-phase dynamic voltage restorer (DVR) that is based on an ac-ac power converter. Two different operations of realizing of the ac-ac converter are proposed in accordance to the application requirement whether phase shift is involved in the output voltage with respect to the input voltage. For inphase compensation, the ac-ac power converter

Bingsen Wang

2010-01-01

25

A comparative study of electric power distribution systems for spacecraft  

NASA Technical Reports Server (NTRS)

The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems.

Stuart, Thomas A.; King, Roger J.

1990-01-01

26

21 CFR 886.1850 - AC-powered slitlamp biomicroscope.  

Code of Federal Regulations, 2010 CFR

...slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is a microscope intended for use in eye examination that projects into a patient's eye through a control diaphragm a thin, intense...

2010-04-01

27

Thermoelectric AC power sensor by CMOS technology  

Microsoft Academic Search

The authors report the development of a thermoelectric AC power sensor (thermoconverter) realized by industrial CMOS IC technology in combination with postprocessing micromachining. The sensor is based on a polysilicon heating resistor and a polysilicon\\/aluminum thermopile integrated on an oxide microbridge. The thermopile sensitivity is 9.9 mV\\/mW and the burn-out power of the sensor is 50 mW. The time constant

Dominik Jaeggi; Henry Baltes; David Moser

1992-01-01

28

The ac power system testbed  

NASA Technical Reports Server (NTRS)

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.

Mildice, J.; Sundberg, R.

1987-01-01

29

Industrial power distribution  

SciTech Connect

This paper is a broad overview of industrial power distribution. Primary focus will be on selection of the various low voltage components to achieve the end product. Emphasis will be on the use of national standards to ensure a safe and well designed installation.

Sorrells, M.A.

1990-01-01

30

Safe-commutation principle for direct single-phase AC-AC converters for use in audio power  

E-print Network

Safe-commutation principle for direct single-phase AC-AC converters for use in audio power-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source is certainly the audio power amplification. Switching-mode Class D audio power amplifiers are becoming

31

Distributed Intelligent Energy Management System for a Single-Phase High-Frequency AC Microgrid  

Microsoft Academic Search

In this paper, a single-phase high-frequency AC (HFAC) microgrid is shown as a novel solution towards integrating renewable energy sources in a distributed generation system. Better utilization of the Microgrid is achieved by solving power flow and power quality issues using p-q theory-based active filtering called universal active power line conditioner and unified power quality conditioner, respectively. A distributed intelligent

Sudipta Chakraborty; Manoja D. Weiss; M. Godoy Simoes

2007-01-01

32

Resonant AC power system proof-of-concept test program  

NASA Technical Reports Server (NTRS)

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.

Wappes, Loran J.

1986-01-01

33

Electrical Model of Balanced AC HTS Power Cable  

NASA Astrophysics Data System (ADS)

The future electricity grid will be more sustainable and it will have more power transmission and distribution capability with more electrical power added from decentralized sources on distribution level and from wind parks and other large sources on transmission level. More interconnections and more underground transmission and distribution will be put up. Use of high temperature superconducting (HTS) power cables provides solutions to many of the future grid problems caused by these trends. In this paper we present an electrical model of a balanced 6 km-long three phase triaxial HTS power cable for the Dutch project being developed by a consortium of Alliander, Ultera™ and TUD. The cable currents in all three phases are balanced by selecting proper twist pitches and insulation thickness. The paper focuses on determining inductances, capacitances and AC losses of the balanced cable. Using the developed model, we also determine the voltage drop as function of the cable length, the neutral current and the effect of the imbalanced capacitances on the current distribution of the Dutch distribution cable. The model is validated and it can be used for accurate simulation of the electrical behaviour of triaxial HTS cables in electrical grids.

Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Willén, D.; Melnik, I.; Geschiere, A.

34

An integrated high power factor three-phase AC-DC-AC converter for AC-machines implemented in one microcontroller  

Microsoft Academic Search

A high power factor three-phase AC-DC-AC power converter for AC machines has been designed and tested. The AC-DC-AC converter is controlled by one single 16-b microcontroller. The converter has two PWM-VSI bridges with common snubber- and drive-circuit topologies. The high power factor rectifier is space vector controlled and the inverter controls an AC-induction machine by an energy optimized strategy. Common

Frede Blaabjerg; John K. Pedersen

1993-01-01

35

Distributed cooperative control of AC microgrids  

NASA Astrophysics Data System (ADS)

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

Bidram, Ali

36

Inverter design for high frequency power distribution  

NASA Technical Reports Server (NTRS)

A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

King, R. J.

1985-01-01

37

Automated Power-Distribution System  

NASA Technical Reports Server (NTRS)

Automated power-distribution system monitors and controls electrical power to modules in network. Handles both 208-V, 20-kHz single-phase alternating current and 120- to 150-V direct current. Power distributed to load modules from power-distribution control units (PDCU's) via subsystem distributors. Ring busses carry power to PDCU's from power source. Needs minimal attention. Detects faults and also protects against them. Potential applications include autonomous land vehicles and automated industrial process systems.

Thomason, Cindy; Anderson, Paul M.; Martin, James A.

1990-01-01

38

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

SciTech Connect

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)

Halimi, B. [Seoul National Univ., Seoul 151-744 (Korea, Republic of); Suh, K. Y. [Seoul National Univ., Seoul 151-744 (Korea, Republic of); PHILOSOPHIA, 1 Gwanak Ro, Gwanak Gu, Seoul 151-744 (Korea, Republic of)

2012-07-01

39

A hybrid electromechanical solid state switch for ac power control  

NASA Technical Reports Server (NTRS)

Bidirectional thyristor coupled to a series of actuator driven electromechanical contacts generates hybrid electromechanical solid state switch for ac power control. Device is useful in power control applications where zero crossover switching is required.

1972-01-01

40

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2012 CFR

...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 adjustable hospital bed is a...

2012-04-01

41

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false AC-powered medical examination light. 880.6320...Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an...

2010-04-01

42

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false AC-powered medical examination light. 880.6320...Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an...

2013-04-01

43

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false AC-powered medical examination light. 880.6320...Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an...

2012-04-01

44

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false AC-powered medical examination light. 880.6320...Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an...

2011-04-01

45

21 CFR 880.6320 - AC-powered medical examination light.  

...2014-04-01 2014-04-01 false AC-powered medical examination light. 880.6320...Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an...

2014-04-01

46

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

...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 adjustable hospital bed is a...

2014-04-01

47

Automated Power-Distribution System  

NASA Technical Reports Server (NTRS)

Autonomous power-distribution system includes power-control equipment and automation equipment. System automatically schedules connection of power to loads and reconfigures itself when it detects fault. Potential terrestrial applications include optimization of consumption of power in homes, power supplies for autonomous land vehicles and vessels, and power supplies for automated industrial processes.

Ashworth, Barry; Riedesel, Joel; Myers, Chris; Miller, William; Jones, Ellen F.; Freeman, Kenneth; Walsh, Richard; Walls, Bryan K.; Weeks, David J.; Bechtel, Robert T.

1992-01-01

48

Airline requirements on aircraft electrical power generation and distribution  

Microsoft Academic Search

Attention is given to airline requirements to aircraft electrical power generation and distribution, such as electrical power generation, namely, basic consideration of conventional AC generator, the Integrated Drive Generator, and the Variable Frequency Generator, including quality of regulation and mechanical mounting; airworthiness requirements to achieve redundancy for normal, stand-by, and emergency systems; maintainability of components and interconnecting systems; and access

Claus Glashagen

1992-01-01

49

A three-phase ac\\/ac power electronic transformer-based PWM ac drive with lossless commutation of leakage energy  

Microsoft Academic Search

This paper presents a novel three-phase ac\\/ac power converter topology with a high frequency ac-link for adjustable speed PWM ac drives. Such drives find applications in electric power generation from renewable energy sources like wind. This converter has a single power conversion stage with bidirectional power flow capability. The high frequency transformer provides voltage transformation, isolation, noise decoupling and high

Kaushik Basu; Apurva Somani; Krushna K Mohapatra; N. Mohan

2010-01-01

50

21 CFR 886.1630 - AC-powered photostimulator.  

Code of Federal Regulations, 2012 CFR

...photostimulator is an AC-powered device intended to provide light stimulus which allows measurement of retinal or visual function by perceptual or electrical methods (e.g., stroboscope). (b) Classification. Class...

2012-04-01

51

21 CFR 886.1630 - AC-powered photostimulator.  

Code of Federal Regulations, 2013 CFR

...photostimulator is an AC-powered device intended to provide light stimulus which allows measurement of retinal or visual function by perceptual or electrical methods (e.g., stroboscope). (b) Classification. Class...

2013-04-01

52

21 CFR 886.1630 - AC-powered photostimulator.  

...photostimulator is an AC-powered device intended to provide light stimulus which allows measurement of retinal or visual function by perceptual or electrical methods (e.g., stroboscope). (b) Classification. Class...

2014-04-01

53

21 CFR 886.1630 - AC-powered photostimulator.  

Code of Federal Regulations, 2010 CFR

...photostimulator is an AC-powered device intended to provide light stimulus which allows measurement of retinal or visual function by perceptual or electrical methods (e.g., stroboscope). (b) Classification. Class...

2010-04-01

54

21 CFR 886.1630 - AC-powered photostimulator.  

Code of Federal Regulations, 2011 CFR

...photostimulator is an AC-powered device intended to provide light stimulus which allows measurement of retinal or visual function by perceptual or electrical methods (e.g., stroboscope). (b) Classification. Class...

2011-04-01

55

Topologies of single-phase inverters for small distributed power generators: an overview  

Microsoft Academic Search

This paper presents an overview of single-phase inverters developed for small distributed power generators. The functions of inverters in distributed power generation (DG) systems include dc-ac conversion, output power quality assurance, various protection mechanisms, and system controls. Unique requirements for small distributed power generation systems include low cost, high efficiency and tolerance for an extremely wide range of input voltage

Yaosuo Xue; Liuchen Chang; Sren Baekhj Kjaer; J. Bordonau; T. Shimizu

2004-01-01

56

EC417 --Electric Energy, Adapting to Renewable Resources Brief History of Power Systems (the great AC-DC battle)  

E-print Network

EC417 -- Electric Energy, Adapting to Renewable Resources Fall 2014 Topics: · Brief History (generation, transmission, distribution -- electric motors and other loads) · Power Plants with emphasis Power and Power Factor calculations · Transformers · Introduction to Power Electronics and AC/DC and DC

57

Main Injector power distribution system  

SciTech Connect

The paper describes a new power distribution system for Fermilab's Main Injector. The system provides 13.8 kV power to Main Injector accelerator (accelerator and conventional loads) and is capable of providing power to the rest of the laboratory (backfeed system). Design criteria, and features including simulation results are given.

Cezary Jach and Daniel Wolff

2002-06-03

58

Quantitative distribution assessment of HoAcAc microspheres and HoPLLA microspheres after direct injection.  

E-print Network

??This experimental study on interstitial brachytherapy describes the distribution of HoAcAc microspheres and HoPLLA microspheres after direct injection in tissue. The microspheres were injected in… (more)

Steenbeek, I.D.

2014-01-01

59

A distributed static series compensator system for realizing active power flow control on existing power lines  

Microsoft Academic Search

Flexible AC transmission systems (FACTS) devices can control power flow in the transmission system to improve asset utilization, relieve congestion, and limit loop flows. High costs and reliability concerns have restricted their use in these applications. The concept of distributed FACTS (D-FACTS) is introduced as a way to remove these barriers. A new device, the distributed static series compensator (DSSC),

D. Divan; W. Brumsickle; R. Schneider; B. Kranz; R. Gascoigne; D. Bradshaw; M. Ingram; I. Grant

2004-01-01

60

A Distributed Static Series Compensator System for Realizing Active Power Flow Control on Existing Power Lines  

Microsoft Academic Search

Flexible AC transmission systems (FACTS) devices can control power flow in the transmission system to improve asset utilization, relieve congestion, and limit loop flows. High costs and reliability concerns have restricted their use in these applications. The concept of distributed FACTS (D-FACTS) is introduced as a way to remove these barriers. A new device, the distributed static series compensator (DSSC),

Deepak M. Divan; William E. Brumsickle; Robert S. Schneider; Bill Kranz; Randal W. Gascoigne; Dale T. Bradshaw; Michael R. Ingram; Ian S. Grant

2007-01-01

61

Design and Implement of a High-Frequency Bridge Type AC-AC Direct Converter for Contactless Power Transfer Systems  

Microsoft Academic Search

\\u000a Focusing on the defects of traditional contactless power transfer systems with an AC-DC-AC power transition type, a high-frequency\\u000a bridge type bidirectional switch AC-AC direct converter was presented to generate the high-frequency current in the primary\\u000a circuit. Applying the principle of energy injection and free oscillation, the operating state of IGBTS were designed and the\\u000a high frequency current in the primary

Xiaomei Chen; Wangqiang Niu; Xiong Zhang

62

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

NASA Technical Reports Server (NTRS)

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 redundancies and including emergency generators on both ac and dc sides is proposed. The generation frequency is 400 Hz mostly because of the technology maturity at this frequency in the aerospace industry. Power will be distributed to several ac load distribution buses through solid state variable speed, constant frequency converters on the ac side. A segmented dc ring bus supplied from ac/dc converters and with the capability of connecting/disconnecting the segments will supply power to multiple de load distribution buses. The system will have the capability of reverse flow from dc to ac side in the case of an extreme emergency on the main ac generation side.

Chowdhury, Badrul H.

2005-01-01

63

A New High-Frequency AC Link Three-Phase Four-Wire Power Electronic Transformer  

Microsoft Academic Search

In this paper, a new three-phase four-wire high-frequency AC link matrix converter is discussed, and the topology of conventional matrix converter is modified with an additional transformer for three-phase four-wire electronic power distribution application. The proposed approach accomplishes high output voltage transfer ratio which is more than unity, galvanic isolation between both voltage sources and higher power density by employing

Jin Aijuan; Li. Hangtian; Li Shaolong

2006-01-01

64

Resistojet control and power for high frequency ac buses  

NASA Technical Reports Server (NTRS)

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.

Gruber, Robert P.

1987-01-01

65

Power Sharing Control between Load-Side Inverters in DC Microgrid for Super High Quality Electric Power Distribution System  

NASA Astrophysics Data System (ADS)

DC microgrid is a novel power system using dc distribution in order to provide a super high quality electric power. The dc distribution system is suitable for dc output type distributed generations such as photovoltaic and fuel cells, and energy storages such as batteries and electric double layer capacitors. Power is distributed through dc distribution line and converted to required ac or dc voltage by converters placed near loads. Load-side single phase inverters are connected through transformers in order to share active and reactive power. In this paper, a power sharing control scheme was proposed, and the power sharing characteristics were demonstrated by experimental results.

Kakigano, Hiroaki; Nada, Kaho; Miura, Yushi; Ise, Toshifumi; Uchida, Ryohei

66

Control Design of a Three-Phase Matrix-Converter-Based AC–AC Mobile Utility Power Supply  

Microsoft Academic Search

This paper describes the control analysis and design of an ac-to-ac three-phase mobile utility power supply using a matrix converter capable of high-quality 50-, 60-, and 400-Hz output voltage and reduced input harmonic distortion. Instead of the traditional structure employing a diode bridge rectifier, a dc link and a pulsewidth-modulated inverter, a three-phase-to-three-phase direct ac-ac (matrix) converter has been used

Pericle Zanchetta; Patrick W. Wheeler; Jon C. Clare; Michael Bland; Lee Empringham; Dimosthenis Katsis

2008-01-01

67

AC-DC Microgrid Optimal Power Flow.  

E-print Network

??Electricity market deregulation has opened the door for novel electricity production schemes within the existing central production paradigm that dominates the electricity power industry. The… (more)

Duggal, Inderjeet

2012-01-01

68

ac power control in the Core Flow Test Loop  

SciTech Connect

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.

McDonald, D.W.

1980-01-01

69

Forty-eighth annual power distribution conference  

SciTech Connect

This book contains papers presented at the Forty-eighth Annual Power Distribution Conference held in 1995 at Austin, Texas. The topics of the papers include power quality in power distribution systems, methods to improve power quality, power system communications, automation of distribution systems, distributed data acquisition, energy efficiency in industrial plants, weather data in operation of distribution systems, detection and location of failed or failing equipment in power distribution systems, lightning and overvoltage protection, distribution cable research update, and equipment protection devices for residential power distribution systems.

NONE

1995-12-31

70

AC/DC Power Systems with Applications in Future Human Habitat on Lunar and Mars Bases  

NASA Astrophysics Data System (ADS)

As NASA readies itself for new space exploration initiatives starting with a human return to the Moon by the year 2020 eventually leading to human exploration of Mars, the requirements for a safe, efficient and comprehensive power system to support the exploration missions as well human habitat will become important issues to consider. Certain issues dealing with electric power generation and distribution on board Mars-bound vehicles and those on Lunar and Martian surfaces are described. The requirements for lightweight power generation dictates the use of a high frequency ac machine. Preliminary results of investigating the design of a permanent magnet synchronous machine is presented.

Chowdhury, Badrul H.; Hossain, Sabbir A.; Lawrence, James T.; Barave, Sushant

2006-01-01

71

Multi-electrodes in SAW with square wave ac power  

SciTech Connect

Examines the feasibility of using AC square wave power for multi-electrode submerged arc welding (SAW) by arranging 2 power sources for weld test using two-electrode submerged arc welding. Presents figures showing phase relationship between lead arc current and trail arc current for Scott connected multi-electrode SAW, and arc deflection vs. electrical degrees. Suggests that Scott connection is preferred because it balances the primary line draw. Concludes that the multielectrode submerged arc process with constant potential square wave power increases travel speed and deposition rates which can be added to the economies obtained from a narrow groove joint configuration and the SAW process.

Bunker, T.A.

1982-07-01

72

Development of an analytical tool to study power quality of AC power systems for large spacecraft  

NASA Technical Reports Server (NTRS)

A harmonic power flow program applicable to space power systems with sources of harmonic distortion is described. The algorithm is a modification of the Electric Power Research Institute's HARMFLO program which assumes a three phase, balanced, AC system with loads of harmonic distortion. The modified power flow program can be used with single phase, AC systems. Early results indicate that the required modifications and the models developed are quite adequate for the analysis of a 20 kHz testbed built by General Dynamics Corporation. This is demonstrated by the acceptable correlation of present results with published data. Although the results are not exact, the discrepancies are relatively small.

Kraft, L. Alan; Kankam, M. David

1991-01-01

73

Development of an analytical tool to study power quality of ac power systems for large spacecraft  

NASA Technical Reports Server (NTRS)

A harmonic power flow program applicable to space power systems with sources of harmonic distortion is described. The algorithm is a modification of Electric Power Research Institute's HARMFLO program which assumes a three-phase, balanced, ac system with loads of harmonic distortion. The modified power flow program can be used with single phase, ac systems. Early results indicate that the required modifications and the models developed are quite adequate for the analysis of a 20-kHz testbed built by General Dynamics Corporation. This is demonstrated by the acceptable correlation of the present results with published data. Although the results are not exact, the discrepancies are relatively small.

Kraft, L. A.; Kankam, M. D.

1991-01-01

74

Improvement of Electric Power Conversion Efficiency of Magnetic Oscillation-Type DC–AC Converter  

Microsoft Academic Search

This paper describes fundamental characteristics of a direct current\\/alternating current (dc-ac) converter utilizing magnetic oscillation. An ac-voltage source such as the line electric power source is connected to an excitation winding of the magnetic oscillation circuit in series. The dc-ac converter can supply electric power to the ac-voltage source, and can control electric power with small signal current, which flows

Shinichi Okanuma; Yoshitomo Ogata

2009-01-01

75

Power Electronic Transformer based Three-Phase PWM AC Drives  

NASA Astrophysics Data System (ADS)

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-mode voltage suppression at the load end, 3) High quality output voltage waveform (comparable to conventional space vector PWM modulated two level inverter) and 4) Minimization of output voltage loss, common-mode voltage switching and distortion of the load current waveform due to leakage inductance commutation. All of the proposed topologies along with the proposed control schemes have been analyzed and simulated in MATLABSimulink. A hardware prototype has been fabricated and tested. The simulation and experimental results verify the operation and advantages of the proposed topologies and their control.

Basu, Kaushik

76

Control of matrix converters for AC power supplies using genetic algorithms  

Microsoft Academic Search

This paper describes the design philosophy, simulation and testing of AC power supplies using matrix converters. Instead of the classical design using a diode bridge rectifier, a DC link and a PWM inverter, a 3-phase to 3-phase direct AC-AC (matrix) converter has been used as the power conditioning core of the system. An optimizing control design method, using a genetic

Pericle Zanchetta; M. Sumner; J. C. Clare; P. W. Wheeler

2004-01-01

77

Influence of Critical Current Density Distribution on Transport AC Losses for Round Superconducting Wire  

NASA Astrophysics Data System (ADS)

The AC loss per cycle per unit length of a round superconducting wire has been theoretically analyzed based on the critical state model and numerically calculated from the power-law model. By using Bean's critical state model, it is found that the distribution of critical current density J c which increases from the center to the edge along a radial direction lowers the loss value. And the sharper the J c varies, the more significant the loss reduction. After considering the coupling of thermoelectric interaction, the results show that the temperature in superconducting wires gradually increases and finally becomes stable. The temperature of stable state has a dependence on the J c distribution and the rise of temperature has an important effect on the AC loss behavior.

Huang, Chen-Guang; Yong, Hua-Dong; Zhou, You-He

2013-07-01

78

Power Normal Distribution Debasis Kundu1  

E-print Network

Power Normal Distribution Debasis Kundu1 and Rameshwar D. Gupta2 Abstract Recently Gupta and Gupta [10] proposed the power normal distribution for which normal distribution is a special case. The power normal distribution is a skewed distri- bution, whose support is the whole real line. Our main aim

Kundu, Debasis

79

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

NASA Astrophysics Data System (ADS)

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.

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

2004-05-01

80

Power distribution in a Josephson package environment  

Microsoft Academic Search

An ac power supply designed to power 8K Josephson logic circuits has been tested in a package environment for the first time. The test was part of an experiment that utilized the essential package components for a Josephson computer. All accessible chip-level power signals had the predicted amplitude variation with frequency over the range 50-400 MHz when normal fabrication tolerances

P. Arnett

1983-01-01

81

AC loss in a tri-axial HTS cable with balanced current distribution  

NASA Astrophysics Data System (ADS)

High temperature superconductor (HTS) cables have been studied because they are more compact compared to conventional copper cables. In power applications of HTS cable AC loss is significantly important, as it is related with capacity and efficiency of the power line. Recently, a tri-axial cable composed of three concentric phases has been intensively developed, because of their reduced amount of HTS tapes, small leakage field, low heat loss when compared to three coaxial HTS cable. However, it experiences additional losses and large leakage field due to inherent imbalanced currents. Inside the tri-axial cable, each phase is subject to out-of-phase magnetic fields formed by other phase layer currents. Because tapes are twisted on successive layers, axial field by outer layers and azimuthal field by inner layers are produced in a tri-axial HTS cable. Any slab in the cable experiences parallel component of magnetic field on the wide faces of the tapes; induced by currents of all layers. Since the fields on tapes generate magnetization losses, they should be calculated in consideration of the balanced current distribution of the tri-axial cable. In this paper, AC loss in the tri-axial HTS cable consisting of one layer per phase is described, theoretically, where the balanced phase current distribution is satisfied through treating two different cable segments. The average AC losses in the cable are calculated as functions of the segment lengths and the segment twist pitches.

Ozcivan, A. N.; Shimoyama, K.; Soeda, S.; Yagai, T.; Tsuda, M.; Hamajima, T.

2008-09-01

82

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

83

A power electronic transformer for three phase PWM AC\\/AC drive with loss less commutation and common-mode voltage suppression  

Microsoft Academic Search

This paper presents a novel topology for the generation of adjustable frequency and magnitude PWM three phase ac from a balanced three phase ac source with a high frequency ac link. The proposed power electronic transformer system provides single stage power conversion with bidirectional power flow capability. This topology along with the proposed control has the following advantages : 1)

K. Basu; N. Mohan

2010-01-01

84

Airline requirements on aircraft electrical power generation and distribution  

NASA Astrophysics Data System (ADS)

Attention is given to airline requirements to aircraft electrical power generation and distribution, such as electrical power generation, namely, basic consideration of conventional AC generator, the Integrated Drive Generator, and the Variable Frequency Generator, including quality of regulation and mechanical mounting; airworthiness requirements to achieve redundancy for normal, stand-by, and emergency systems; maintainability of components and interconnecting systems; and access to internal subcomponents. Another requirement is interconnection and installation, which involve undervalued efforts required for the maintenance and repair of interconnecting and installation components. This includes hardware selection of cables, clamps, connectors, and terminals. Environmental considerations. Also discussed are electrical power distribution components, involving electro-mechanical switches and remote controlled circuit breakers in a cost-effective distribution system.

Glashagen, Claus

85

Load characteristics analysis of AC and DC arc furnaces using various power definitions and statistic method  

Microsoft Academic Search

Various power definitions and statistics are used to investigate the load characteristics of AC and DC electric arc furnaces, which occupy a major percentage of the Taiwan power system. It is very important to note their effects on power quality. It is also desirable to have an alternative way to study their load behaviors. Since AC and DC arc furnaces

Tsu-Hsun Fu; Chi-Jui Wu

2002-01-01

86

Load Characteristics Analysis of AC and DC Arc Furnaces Using Various Power Definitions and Statistic Method  

Microsoft Academic Search

Various power definitions and statistics are used to investigate the load characteristics of ac and dc electric arc furnaces, which occupy a major percentage of the Taiwan power system. It is very important to note their effect on power quality. It is also desired to have an alternative way to study their load behaviors. Since ac and dc arc furnaces

T. H. Fu; C. J. Wu

2002-01-01

87

Power control of a wind farm with active stall wind turbines and AC grid connection  

E-print Network

Power control of a wind farm with active stall wind turbines and AC grid connection Anca D. Hansen1 on the wind farm level. The ability of active stall wind farms with AC grid connection to regulate the power. Keywords: wind farm control, active stall wind turbine, power system control 1 Introduction The recent

88

Lurching towards markets for power: China's electricity policy 19852007 Xiaoli Zhao a,c,  

E-print Network

Institute for Low Carbon Economy and Trade, North China Electric Power University, Beijing, China a r t i cLurching towards markets for power: China's electricity policy 1985­2007 Xiaoli Zhao a,c, , Thomas P. Lyon b , Cui Song a,c a School of Economics and Management, North China Electric Power University

Lyon, Thomas P.

89

AC and DC arc furnaces: a comparison on some power quality aspects  

Microsoft Academic Search

The paper deals with a comparison between AC and DC arc furnaces taking into account power quality indices. The study is performed using computer simulation based on the ATP program, assuming as reference a real AC arc furnace plant. Flicker phenomenon, harmonic and interharmonic distortion are evaluated for both DC and AC arc furnaces

G. Carpinelli; M. DiManno; P. Verde; E. Tironi; D. Zaninelli

1999-01-01

90

Point of collapse methods applied to AC\\/DC power systems  

Microsoft Academic Search

The authors describe an extension of the point of collapse method developed for studies of AC systems to the determination of saddle-node bifurcations in power systems including high voltage direct current (HVDC) transmission. Bus voltage profiles are illustrated for an AC\\/DC test system. They significantly differ from the profiles of pure AC systems for typical system models. In particular, voltage

C. A. Canizares; Fernando L. Alvarado; Christopher L. DeMarco; Ian Dobson; Willis F. Long

1992-01-01

91

A Comparative Evaluation of Series Power-Flow Controllers Using DC and AC-Link Converters  

Microsoft Academic Search

This paper presents a comparative evaluation of direct AC-AC converters and multipulse voltage source DC-AC converters for providing series compensation of transmission systems. This paper provides a detailed discussion of power circuit design issues related to various performance considerations for both approaches. A benchmark case study is used to demonstrate the operation and performance of both designs in terms of

Fernando Mancilla-David; Subhashish Bhattacharya; Giri Venkataramanan

2008-01-01

92

A three-phase four-wire high-frequency AC link matrix converter for power electronic transformer  

Microsoft Academic Search

In this paper, a new three-phase four-wire high-frequency AC link matrix converter is discussed, and the topology of conventional matrix converter is modified with an additional transformer for three-phase four-wire power distribution application. The proposed approach accomplishes high output voltage transfer ratio which is more than unity, galvanic isolation between both voltage sources and higher power density by employing a

Jin Aijuan; Li Hangtian; Li Shaolong

2005-01-01

93

Transient stability enhancement in power system with distributed static series compensator (DSSC)  

Microsoft Academic Search

Long distance AC transmission system is often subjected to stability problems which limit the transmission capability. Large power systems often suffer from weakly damped swings between synchronous generators. This paper aims to enhance the transient stability of the power system with the use of distributed static series compensator (DSSC). First of all, a detailed simulation model of the DSSC has

S. Golshannavaz; M. Mokhtari; M. Khalilian; D. Nazarpour

2011-01-01

94

Power scalable processing using distributed arithmetic  

Microsoft Academic Search

A recent trend in low power design has been the employment of reduced precision processing methods for decreasing arithmetic activity and average power dissipation. Such designs can trade off power and arithmetic precision as system requirements change. This work explores the potential of Distributed Arithmetic (DA) computation structures for low power precisionon-demand computation. We present two proof-ofconcept VLSI implementations whose

Rajeevan Amirtharajah; Thucydides Xanthopoulos; Anantha Chandrakasan

1999-01-01

95

HF power combining and distributing devices  

Microsoft Academic Search

The work describes the theoretical bases and design principles of bridge-type devices for the power combining and distributing of HF and microwave oscillations. Various types of bridge devices, based on distributed and lumped parameter elements, for various frequency ranges are considered. New solutions are presented for multiterminal and wideband devices, especially of transformer type. Attention is given to power combining

V. V. Zaentsev; V. M. Katushkina; S. E. London; Z. I. Model

1980-01-01

96

Communication Infrastructures for Distributed Control of Power Distribution Networks  

Microsoft Academic Search

Power distribution networks with distributed gener- ators (DGs) can exhibit complex operational regimes which makes conventional management approaches no longer adequate. This paper looks into key communication infrastructure design aspects, and analyzes two representative evolution cases of Active Network Management (ANM) for distributed control. Relevant standard initiatives, communication protocols and technologies are intro- duced and underlying engineering challenges are highlighted.

Qiang Yang; Javier A. Barria; Tim C. Green

2011-01-01

97

Control of a Matrix Converter-based AC Power Supply for Aircrafts under Unbalanced Conditions  

Microsoft Academic Search

This paper deals with the design, control and implementation of a 10 kVA three-phase ground power supply unit (GPU) for aircraft servicing. Instead of a classical back to back converter configuration, a 3-phase to 3-phase direct AC-AC (matrix) converter has been used as the power conditioning core of the power supply, working in conjunction with input and output LC filters.

S. L. Arevalo; Pericle Zanchetta; P. W. Wheeler

2007-01-01

98

Low cost DC to AC converter for photovoltaic power conversion in residential applications  

Microsoft Academic Search

The development and experimental results of a low-cost 500-W DC-AC power converter for photovoltaic power conversion in residential applications are described. The converter uses low-cost technology usually applied in consumer products. The DC-AC converter is specially designed for operation at a wide DC input voltage range (30-170 V) in order to allow optimal power conversion with an arbitrary number of

U. Herrmann; Hans Georg Langer; Heinz van der Broeck

1993-01-01

99

Control of Distributed Uninterruptible Power Supply Systems  

Microsoft Academic Search

In the last years, the use of distributed uninterruptible power supply (UPS) systems has been growing into the market, becoming an alternative to large conventional UPS systems. In addition, with the increasing interest in renewable energy integration and distributed generation, distributed UPS systems can be a suitable solution for storage energy in micro grids. This paper depicts the most important

Josep M. Guerrero; Lijun Hang; Javier Uceda

2008-01-01

100

Multiinput Direct DC–AC Converter With High-Frequency Link for Clean Power-Generation Systems  

Microsoft Academic Search

This paper proposes a new topology for bidirectional multiinput direct dc-ac converter for clean-power-generation sys- tem, therefore, at the input port, a boost converter is used to meet the requirement of many distributed generation systems, such as photovoltaic, and fuel cell systems. The boost converter can in- crease the dc input voltage. This point results in a turn ratio re-

Mitra Sarhangzadeh; Seyed Hossein Hosseini; Mohammad Bagher Bannae Sharifian; Gevorg B. Gharehpetian

2011-01-01

101

Emergency ac power systems operating experience at US nuclear power plants, 1976 through 1983. [Diesel generator  

SciTech Connect

Success and failure data of test and emergency starts of emergency ac power sources (diesel generators) at US nuclear power plants were collected and evaluated to estimate diesel generator reliability parameters. A regression analysis of the estimates of the probability of failure to start based on surveillance test data from 1976 through 1983 indicates that the probability of failure to start has been decreasing. However, the reliability of diesel generator performance during losses of off-site power for 1981 through 1983 was less than expected based on the test data estimates. The failures that occurred during losses of off-site power were reviewed to determine why the calculated failure to start was greater than expected, and possible explanations for this high value are presented. The subsystems involved in diesel generator subsystem failures were categorized to determine whether there were any dominant failure modes. The results indicate that further significant improvement in diesel generator reliability will require improvement of many subsystems.

Battle, R.E.

1985-01-01

102

Power scalable processing using distributed arithmetic  

Microsoft Academic Search

A recent trend in low power design has been the employment of reduced precision processing methods for decreasing arithmetic activity and average power dissipation. Such designs can trade off power and arithmetic precision as system requirements change. This work explores the potential of Distributed Arithmetic (DA) computation structures for low power precision-on-demand computation. We present two proof-of-concept VLSI implementations whose

Rajeevan Amirtharajah; Thucydides Xanthopoulos; Anantha Chandrakasan

1999-01-01

103

Experimental measurement of non-characteristic harmonic power generated by thyristor pulse-controlled AC\\/DC three phase converters  

Microsoft Academic Search

This paper presents an experimental investigation to measure the noncharacteristic harmonic power caused by network asymmetries in the AC source feeding thyristor-controlled AC\\/DC three-phase power converters. The experimental measurements were made in an AC\\/DC\\/AC transmission link physical model. Two three-phase power converters linked by a lumped parameters transmission line operate in rectifying and inverting modes, respectively. The converter acting in

Alfriedo Nava Segura; P. B. Sanchez

1996-01-01

104

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

Microsoft Academic Search

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

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

2004-01-01

105

Electric power distribution and load transfer system  

NASA Technical Reports Server (NTRS)

A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

1987-01-01

106

Electric power distribution and load transfer system  

NASA Technical Reports Server (NTRS)

A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

1989-01-01

107

A self-powered AC magnetic sensor based on piezoelectric nanogenerator  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

108

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

PubMed

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

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

2014-11-14

109

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2010 CFR

... AC-powered adjustable hospital bed. 880.5100 Section...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use...

2010-04-01

110

Computer Power: Part 1: Distribution of Power (and Communications).  

ERIC Educational Resources Information Center

Discussion of the distribution of power to personal computers and computer terminals addresses options such as extension cords, perimeter raceways, and interior raceways. Sidebars explain: (1) the National Electrical Code; (2) volts, amps, and watts; (3) transformers, circuit breakers, and circuits; and (4) power vs. data wiring. (MES)

Price, Bennett J.

1988-01-01

111

A Simple Three-Phase Model for Distributed Static Series Compensator (DSSC) in Newton Power Flow  

Microsoft Academic Search

Load flow problems have always been an important issue in power system analysis and require proper modeling of system components. In this regard flexible AC transmission system (FACTS) controllers are modern devices that their modeling specially the series type is a challenging topic. This paper describes a three-phase model for distributed static series compensator (DSSC) based on extending the static

Reza Jalayer; Hossein Mokhtari

2009-01-01

112

High-Power Converters and AC Drives IEEE PESC2005 Tutorial  

E-print Network

@ee.ryerson.ca http://www.ee.ryerson.ca/~bwu/ 2 High-Power Converters and AC Drives 1. Introduction 2. Cascaded H-Bridge · Multilevel Voltage Source Inverters N dC Cascaded H-bridge (CHB) Inverter dC Two Level Inverter dC Flying1 High-Power Converters and AC Drives IEEE PESC2005 Tutorial Bin Wu PhD, PEng Professor Ryerson

Wu, Bin

113

Ac-Ac Dual Active Bridge Converter for Solid State Transformer  

E-print Network

converters as distribution transformers [1]. A power electronics-based solid state transformer (SST) providesAc-Ac Dual Active Bridge Converter for Solid State Transformer Hengsi Qin and Jonathan W. Kimball--Solid State Transformer, Dual Active Bridge Converter, Ac-Ac Converter, Zero Voltage Switching I. INTRODUCTION

Kimball, Jonathan W.

114

Cathode power distribution system and method of using the same for power distribution  

DOEpatents

Embodiments include a cathode power distribution system and/or method of using the same for power distribution. The cathode power distribution system includes a plurality of cathode assemblies. Each cathode assembly of the plurality of cathode assemblies includes a plurality of cathode rods. The system also includes a plurality of bus bars configured to distribute current to each of the plurality of cathode assemblies. The plurality of bus bars include a first bus bar configured to distribute the current to first ends of the plurality of cathode assemblies and a second bus bar configured to distribute the current to second ends of the plurality of cathode assemblies.

Williamson, Mark A; Wiedmeyer, Stanley G; Koehl, Eugene R; Bailey, James L; Willit, James L; Barnes, Laurel A; Blaskovitz, Robert J

2014-11-11

115

Power Efficiency in Wireless Network Distributed Computing  

Microsoft Academic Search

Advanced wireless applications such as sensor networks involve a close interaction between the communication and computation processes that deliver the services under stringent power constraints. Wireless network distributed computing (WNDC) is a potential solution to reducing the power consumption per node as well as that of the network. In WNDC, a computational task is executed among a network of collaborative

Dinesh Datla; Xuetao Chen; Timothy R. Newman; Jeffrey H. Reed; Tamal Bose

2009-01-01

116

Expert System Detects Power-Distribution Faults  

NASA Technical Reports Server (NTRS)

Autonomous Power Expert (APEX) computer program is prototype expert-system program detecting faults in electrical-power-distribution system. Assists human operators in diagnosing faults and deciding what adjustments or repairs needed for immediate recovery from faults or for maintenance to correct initially nonthreatening conditions that could develop into faults. Written in Lisp.

Walters, Jerry L.; Quinn, Todd M.

1994-01-01

117

A Distributed Monitoring System For Power Quality  

Microsoft Academic Search

In the present paper, prototype architecture for a distributed system for online power quality parameters monitoring is illustrated. An interconnection between two different server types was performed. The remote processing and exchange of information on geographically distributed systems is a reality that becomes more and more integrating part of the technical and civil life. In this context the automation of

C. Donciu; C. Schreiner; M. Cretu; E. Lunca

118

Intelligent Systems for Power Management and Distribution  

NASA Technical Reports Server (NTRS)

The motivation behind an advanced technology program to develop intelligent power management and distribution (PMAD) systems is described. The program concentrates on developing digital control and distributed processing algorithms for PMAD components and systems to improve their size, weight, efficiency, and reliability. Specific areas of research in developing intelligent DC-DC converters and distributed switchgear are described. Results from recent development efforts are presented along with expected future benefits to the overall PMAD system performance.

Button, Robert M.

2002-01-01

119

Annual Power Distribution Conference, 33rd, 1980  

SciTech Connect

The Conference proceedings comprise 16 papers, 15 of which are indexed separately. The subjects considered are: the EPRI distribution research program review; dynamic on-line control using microcomputer systems; tracing and electrical heating of pipelines; power demand limit control; emergency restoration plan at Dallas Power and Light Company; tornado recovery; recovery from hurricanes; shredding and incineration of PCB capacitors; destruction of organochlorine wastes by a liquid waste incinerator; methods and materials to reduce cable failure due to treeing; thermal performance of underground cable: field tests; a utility's progress towards switching 20/30.5 kV URD; field experience with non-porcelain insulators; improving productivity in distribution; distribution losses.

Not Available

1980-01-01

120

Hierarchical distributed stabilization of power networks  

NASA Astrophysics Data System (ADS)

Large fluctuation of electric power due to high penetration of renewable energy sources such as photovoltaic and wind power generation increases the risk to make the whole power network system unstable. The conventional frequency control called load frequency control is based on PID (proportional-integral-derivative) control or more advanced centralized and decentralized/distributed control. If we could more effectively use information on the state of the other neighbor generators, we can expect to make the whole system more robust against the large frequency fluctuation. This paper proposes a fundamental framework towards the design of hierarchical distributed stabilizing controllers for a network of power generators and loads. This novel type of distributed controller, composed of a global controller and a set of local controllers, takes into account the effect of the interaction among the generators and loads to improve robustness for the variation of locally stabilizing controllers.

Ishizaki, Takayuki; Sadamoto, Tomonori; Imura, Jun-ichi

2014-09-01

121

Hierarchical distributed stabilization of power networks  

NASA Astrophysics Data System (ADS)

Large fluctuation of electric power due to high penetration of renewable energy sources such as photovoltaic and wind power generation increases the risk to make the whole power network system unstable. The conventional frequency control called load frequency control is based on PID (proportional-integral-derivative) control or more advanced centralized and decentralized/distributed control. If we could more effectively use information on the state of the other neighbor generators, we can expect to make the whole system more robust against the large frequency fluctuation. This paper proposes a fundamental framework towards the design of hierarchical distributed stabilizing controllers for a network of power generators and loads. This novel type of distributed controller, composed of a global controller and a set of local controllers, takes into account the effect of the interaction among the generators and loads to improve robustness for the variation of locally stabilizing controllers.

Ishizaki, Takayuki; Sadamoto, Tomonori; Imura, Jun-ichi

2014-10-01

122

Control of parallel connected inverters in standalone AC supply systems  

Microsoft Academic Search

A scheme for controlling parallel-connected inverters in a standalone AC supply system is presented. This scheme is suitable for control of inverters in distributed source environments such as in isolated AC systems, large and distributed uninterruptible power supply (UPS) systems, photovoltaic systems connected to AC grids, and low-voltage DC power transmission meshes. A key feature of the control scheme is

Mukul C. Chandorkar; D. M. Divan; R. Adapa

1993-01-01

123

Optical power distributions through fractal routing  

NASA Astrophysics Data System (ADS)

Several applications in integrated optics require an equal distribution of power from a single input port among many photonic components, whether they be projection components or sensors. One method of achieving such a system is through using progressively more tightly coupled evanescent couplers to route power from a single feeding line [1]. While very compact, this approach requires careful design and characterization of evanescent couplers, and is vulnerable to process variations as the ratio of coupling has a non-linear relation to the couplers' gap size. Fractals, widely present in nature, are recursive objects where each section is geometrically similar to its parent. They find applications in various fields [2], including RF antenna design and feeding [3]. In this paper we propose to use the fractal approach for spreading power evenly over an area using micro-machined photonic waveguides. In the fractal routing demonstrated in this work, an 1×2 multimode interference (MMI) coupler splits the power at each fractal stage. This provides several advantages. First, only one power splitter design is needed. Second, MMI couplers are well known, and more robust to process tolerances than evanescent couplers [3]. Third, they are symmetrical, and therefore provide a theoretically perfect power distribution independent of the fractal depth. We therefore demonstrate that a fractal routing provides a way to evenly and efficiently distribute power over a large area.

Jansen, Roelof; Claes, Tom; Neutens, Pieter; Du Bois, Bert; Helin, Philippe; Severi, Simone; Van Dorpe, Pol; Deshpande, Paru; Rottenberg, Xavier

2014-05-01

124

Fault-tolerant power distribution system  

NASA Technical Reports Server (NTRS)

A fault-tolerant power distribution system which includes a plurality of power sources and a plurality of nodes responsive thereto for supplying power to one or more loads associated with each node. Each node includes a plurality of switching circuits, each of which preferably uses a power field effect transistor which provides a diode operation when power is first applied to the nodes and which thereafter provides bi-directional current flow through the switching circuit in a manner such that a low voltage drop is produced in each direction. Each switching circuit includes circuitry for disabling the power field effect transistor when the current in the switching circuit exceeds a preselected value.

Volp, Jeffrey A. (Inventor)

1987-01-01

125

AC loss in a tri-axial HTS cable with balanced current distribution  

Microsoft Academic Search

High temperature superconductor (HTS) cables have been studied because they are more compact compared to conventional copper cables. In power applications of HTS cable AC loss is significantly important, as it is related with capacity and efficiency of the power line. Recently, a tri-axial cable composed of three concentric phases has been intensively developed, because of their reduced amount of

A. N. Ozcivan; K. Shimoyama; S. Soeda; T. Yagai; M. Tsuda; T. Hamajima

2008-01-01

126

Power distribution studies for CMS forward tracker  

SciTech Connect

The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.; /Fermilab

2009-01-01

127

AC current distribution and losses in multifilamentary superconductors exposed to longitudinal magnetic field  

Microsoft Academic Search

The current distribution and also AC losses, in a multifilamentary superconductor carrying a transport current, are influenced by the self and the external magnetic field. By using the Maxwell equations, a model has been developed in order to calculate the temporal evolution of current distribution in a single wire exposed or not to external magnetic field. This model is based

S. Le Naour; A. Lacaze; Y. Laumond; P. Estop; T. Verhaege

1996-01-01

128

A power electronic transformer-based three-phase PWM ac drive with lossless commutation of leakage energy  

Microsoft Academic Search

This paper proposes a novel dc\\/ac converter topology with a high frequency ac-link for three-phase adjustable speed PWM ac drives. Such drives find applications in UPS systems and renewable energy sources like solar and fuel cells. This topology provides single-stage power conversion with bidirectional power flow capability. The high frequency transformer offers the benefits of galvanic isolation and high power

Kaushik Basu; Apurva Somani; Krushna K Mohapatra; N. Mohan

2010-01-01

129

The Hybrid Power Flow Controller A New Concept for Flexible AC Transmission  

E-print Network

Power and Propulsion Systems Lab GE Global Research Niskayuna, NY, USA Email: bebic flow controller topologies are proposed for flexible AC transmission systems (FACTS). The first one the converters can exchange active power through a common DC circuit. Both topologies make combined use

Lehn, Peter W.

130

Development of software to improve AC power quality on large spacecraft  

NASA Technical Reports Server (NTRS)

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.

Kraft, L. Alan

1991-01-01

131

High efficiency DC/AC power converter for photovoltaic applications  

E-print Network

This thesis presents the development of a microinverter for single-phase photovoltaic applications that is suitable for conversion from low-voltage (25-40V) DC to high voltage AC (e.g. 240VAC,RMS). The circuit topology is ...

Trubitsyn, Aleksey

2010-01-01

132

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

NASA Astrophysics Data System (ADS)

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.

Peak, S. C.

1982-09-01

133

Three-phase, power quality improvement ac\\/dc converters  

Microsoft Academic Search

The generation of harmonics and reactive power flow in a power system is greatly influenced by the widespread use of power electronic converters in addition to other sources of harmonics and reactive power. The design, development and successful application of single-phase, power quality improvement converters in domestic, commercial and industrial environment has made possible the design and development of three-phase,

Abdul Hamid Bhat; Pramod Agarwal

2008-01-01

134

Approaches to building single-stage AC/AC conversion switch-mode audio power Petar Ljusev and Michael A.E. Andersen  

E-print Network

Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers Petar Ljusev and Michael A.E. Andersen �rsted · DTU, Automation, Technical University of Denmark Elektrovej, DTU Building 325, DK-2800 Kgs. Lyngby, Denmark E-mail: pl@oersted.dtu.dk, ma@oersted.dtu.dk Abstract

135

*This project was sponsored in part by NNSF of China (Grant No.69973039) and NSF of USA (Grant No. Low Power DCVSL Circuits Employing AC Power Supply  

E-print Network

, and the energy conversion remains an electric energy to heat conversion. Therefore, circuits supplied with AC. 9988441). Low Power DCVSL Circuits Employing AC Power Supply Xunwei Wu Institute of Circ. and Syst. Ningbo of changing the type of energy conversion in CMOS circuits, this paper investigates low power CMOS circuit

Pedram, Massoud

136

Network integration of distributed power generation  

Microsoft Academic Search

The world-wide move to deregulation of the electricity and other energy markets, concerns about the environment, and advances in renewable and high efficiency technologies has led to major emphasis being placed on the use of small power generation units in a variety of forms. The paper reviews the position of distributed generation (DG, as these small units are called in

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

2002-01-01

137

Power-Law Distributions: Beyond Paretian Fractality  

Microsoft Academic Search

The notion of fractality, in the context of positive-valued probability distributions, is conventionally associated with the class of Paretian probability laws. In this research we show that the Paretian class is merely one out of six classes of probability laws - all equally entitled to be ordained fractal, all possessing a characteristic power-law structure, and all being the unique fixed

Iddo Eliazar; Joseph Klafter

2008-01-01

138

A Study of AC link and DC link Method for Wind Power Generation Connected to Electric Power System  

NASA Astrophysics Data System (ADS)

In this paper, grid-connected of the wind power generator was evaluated from viewpoint of the frequency fluctuation. The wind power generation system is the power generation method that depends on natural energy. Therefore, it is feared to exert a bad influence for the electric power quality. As a result, it is necessary to maintain a high electric power quality to do wind power generation in grid-connected. AC link method,AC-DC link method, and DC link method are enumerated by grid-connected of the wind power generator. The model system was constructed with the use of synchronous generator and induction generator as wind power generator, and the verification experiment was done. The verification experiments that use various grid-connected methods in each generator were conducted. As a result, the steadiest frequency characteristic was obtained in the DC link method. The result in which the stability level is especially the highest in the wind power generation system that adopted DC link method that used wound-rotor induction generator was obtained. Generally, induction generator have grid-connect by AC link method. Therefore, the effectiveness of grid-connected method of induction generator by DC link method could be proven when evaluating it from viewpoint of the frequency fluctuation.

Yukita, Kazuto; Washizu, Shinsuke; Nakano, Hiroyuki; Torii, Akihiro; Ueda, Akiteru; Goto, Yasuyuki; Ichiyanagi, Katsuhiro

139

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 25.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2013-01-01

140

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 25.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2010-01-01

141

14 CFR 23.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 23.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2012-01-01

142

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 25.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2012-01-01

143

14 CFR 23.1310 - Power source capacity and distribution.  

...2014-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 23.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2014-01-01

144

14 CFR 23.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 23.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2013-01-01

145

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 25.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2011-01-01

146

14 CFR 25.1310 - Power source capacity and distribution.  

...2014-01-01 false Power source capacity and distribution...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...General § 25.1310 Power source capacity and distribution...rules and that requires a power supply is an “essential...

2014-01-01

147

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

DOEpatents

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.

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

1987-07-30

148

Microprocessor-based control for an ac-dc power conversion system with dc interrupter protection  

SciTech Connect

The use of microprocessors in power converted controls is of interest, since they could potentially reduce system costs, increase system adaptability, and enhance system reliability where analog circuitry is conventionally used. This report discusses the techniques that were applied in designing a complete microprocessor-controlled ac/dc power conversion system, including thyristor-gating control and closed-loop regulation of system voltages. The project also served as a vehicle for further evaluation of a ringing-bypass valve dc interrupter that had been previously designed in work related to the ac/dc conversion system used here. The microprocessor control techniques described here are applicable to most energy conversion systems where a dc power source exchanges energy with an ac network via line-commutated converters. 4 refs., 33 figs.

Kovalsky, L.J.; Putkovich, R.P.

1982-12-20

149

System for transmitting low frequency analog signals over AC power lines  

DOEpatents

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.

Baker, Steven P. (Powell, TN); Durall, Robert L. (Lenoir City, TN); Haynes, Howard D. (Knoxville, TN)

1989-01-01

150

The ac power line protection for an IEEE 587 Class B environment  

NASA Technical Reports Server (NTRS)

The 587B series of protectors are unique, low clamping voltage transient suppressors to protect ac-powered equipment from the 6000V peak open-circuit voltage and 3000A short circuit current as defined in IEEE standard 587 for Category B transients. The devices, which incorporate multiple-stage solid-state protector components, were specifically designed to operate under multiple exposures to maximum threat levels in this severe environment. The output voltage peaks are limited to 350V under maximum threat conditions for a 120V ac power line, thus providing adequate protection to vulnerable electronic equipment. The principle of operation and test performance data is discussed.

Roehr, W. D.; Clark, O. M.

1984-01-01

151

Non-oxidized porous silicon-based power AC switch peripheries  

PubMed Central

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

2012-01-01

152

Point of collapse methods applied to ac/dc power systems  

SciTech Connect

This paper describes an extension of the Point of Collapse method developed for ac systems studies to the determination of saddle-node bifurcations in power systems including high voltage direct current (HVDC) transmission. Bus voltage profiles are illustrated for an ac/dc test system, which significantly differ from the profiles of pure ac systems for typical system models. In particular, voltage dependent current order limits (VDCOLs) are shown to affect the voltage profiles (nose curves) and the loadability margin of the system. It is also shown that Hopf bifurcations, which are not possible in purely ac lossless systems with second-order generator models, become plausible when the dynamics for the HVDC system are included.

Canizares, C.A.; Alvarado, F.L.; DeMarco, C.L.; Dobson, I.; Long, W.F. (Wisconsin Univ., Madison, WI (United States))

1992-05-01

153

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

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

154

System for conveniently providing load testing termination of an AC power source having at least one battery  

NASA Astrophysics Data System (ADS)

An AC uninterruptible power source is disclosed that provides multiphase power output signals for actual use and a selectable single phase power output signal for use in testing. The AC uninterruptible power source further comprises at least one battery. The single phase output signal is connected to a dummy load by means of a power switch of the break before make type. The invention further includes the dummy load as preferably having metering capabilities to measure the frequency, current, and voltage parameters of the single phase output signal. The arrangement of the present invention allows for the single phase output to be mated to the dummy load without the need of removing input power to the AC uninterruptible power source so as to reduce, or even eliminate, transient caused failures to the AC uninterruptible power source and to its sensitive load equipment which the power source services.

Morell, Wilbert J., III

1995-05-01

155

Reversible unity power factor step-up\\/step-down AC-DC converter controlled by sliding mode  

Microsoft Academic Search

A reversible step-up\\/step-down AC-DC converter is presented in this paper. It is a fifth-order system, capable of managing power transfer from a DC source to an AC one, with any ratio between the DC and the AC voltage levels, and producing a sinusoidal output current, using only one power processing stage. By reversing the energy flow this circuit becomes a

Ivan Eidt Colling; Ivo Barbi

2001-01-01

156

Development of software to improve AC power quality on large spacecraft  

NASA Technical Reports Server (NTRS)

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.

Kraft, L. Alan

1991-01-01

157

A new high performance AC to DC rectifier with input power factor correction and harmonic reduction capacity  

E-print Network

Many conventional switching power supplies in data processing equipment and low power motor drive systems operate by rectifying the input ac line voltage and filtering it with large electrolytic capacitors. Because this process involves both...

Martinez, Roberto

2012-06-07

158

Hardware model of a shipboard zonal electrical distribution system (ZEDS) : alternating current/direct current (AC/DC)  

E-print Network

A hardware model of a shipboard electrical distribution system based on aspects of the DDG 51 Flight IIA, Arleigh Burke class, 60Hz Alternating Current (AC) and the future direct current (DC), zonal electrical distribution ...

Tidd, Chad N. (Chad Norman)

2010-01-01

159

A distributed control approach for power and energy management in a notional shipboard power system  

NASA Astrophysics Data System (ADS)

The main goal of this thesis is to present a power control module (PCON) based approach for power and energy management and to examine its control capability in shipboard power system (SPS). The proposed control scheme is implemented in a notional medium voltage direct current (MVDC) integrated power system (IPS) for electric ship. To realize the control functions such as ship mode selection, generator launch schedule, blackout monitoring, and fault ride-through, a PCON based distributed power and energy management system (PEMS) is developed. The control scheme is proposed as two-layer hierarchical architecture with system level on the top as the supervisory control and zonal level on the bottom as the decentralized control, which is based on the zonal distribution characteristic of the notional MVDC IPS that was proposed as one of the approaches for Next Generation Integrated Power System (NGIPS) by Norbert Doerry. Several types of modules with different functionalities are used to derive the control scheme in detail for the notional MVDC IPS. Those modules include the power generation module (PGM) that controls the function of generators, the power conversion module (PCM) that controls the functions of DC/DC or DC/AC converters, etc. Among them, the power control module (PCON) plays a critical role in the PEMS. It is the core of the control process. PCONs in the PEMS interact with all the other modules, such as power propulsion module (PPM), energy storage module (ESM), load shedding module (LSHED), and human machine interface (HMI) to realize the control algorithm in PEMS. The proposed control scheme is implemented in real time using the real time digital simulator (RTDS) to verify its validity. To achieve this, a system level energy storage module (SESM) and a zonal level energy storage module (ZESM) are developed in RTDS to cooperate with PCONs to realize the control functionalities. In addition, a load shedding module which takes into account the reliability of power supply (in terms of quality of service) is developed. This module can supply uninterruptible power to the mission critical loads. In addition, a multi-agent system (MAS) based framework is proposed to implement the PCON based PEMS through a hardware setup that is composed of MAMBA boards and FPGA interface. Agents are implemented using Java Agent DEvelopment Framework (JADE). Various test scenarios were tested to validate the approach.

Shen, Qunying

160

ACS imaging of star clusters in M51. I. Identification and radius distribution  

E-print Network

We use HST/ACS observations of the spiral galaxy M51 in F435W, F555W and F814W to select a large sample of star clusters with accurate effective radius measurements in an area covering the complete disc of M51. We present the dataset and study the radius distribution and relations between radius, colour, arm/interarm region, galactocentric distance, mass and age. We select a sample of 7698 (F435W), 6846 (F555W) and 5024 (F814W) slightly resolved clusters and derive their effective radii by fitting the spatial profiles with analytical models convolved with the point spread function. The radii of 1284 clusters are studied in detail. We find cluster radii between 0.5 and ~10 pc, and one exceptionally large cluster candidate with a radius of 21.6 pc. The median radius is 2.1 pc. We find 70 clusters in our sample which have colours consistent with being old GC candidates and we find 6 new "faint fuzzy" clusters in, or projected onto, the disc of M51. The radius distribution can not be fitted with a power law, but a log-normal distribution provides a reasonable fit to the data. This indicates that shortly after the formation of the clusters from a fractal gas, their radii have changed in a non-uniform way. We find an increase in radius with colour as well as a higher fraction of redder clusters in the interarm regions, suggesting that clusters in spiral arms are more compact. We find a correlation between radius and galactocentric distance which is considerably weaker than the observed correlation for old Milky Way GCs. We find weak relations between cluster luminosity and radius, but we do not observe a correlation between cluster mass and radius.

R. A. Scheepmaker; M. R. Haas; M. Gieles; N. Bastian; S. S. Larsen; H. J. G. L. M. Lamers

2007-04-26

161

Independent Orbiter Assessment (IOA): Analysis of the Electrical Power Distribution and Control Subsystem, Volume 2  

NASA Technical Reports Server (NTRS)

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C) hardware. The EPD and C hardware performs the functions of distributing, sensing, and controlling 28 volt DC power and of inverting, distributing, sensing, and controlling 117 volt 400 Hz AC power to all Orbiter subsystems from the three fuel cells in the Electrical Power Generation (EPG) subsystem. Volume 2 continues the presentation of IOA analysis worksheets and contains the potential critical items list.

Schmeckpeper, K. R.

1987-01-01

162

Photovoltaic Power System and Power Distribution Demonstration for the Desert RATS Program  

NASA Technical Reports Server (NTRS)

A stand alone, mobile photovoltaic power system along with a cable deployment system was designed and constructed to take part in the Desert Research And Technology Studies (RATS) lunar surface human interaction evaluation program at Cinder Lake, Arizona. The power system consisted of a photovoltaic array/battery system. It is capable of providing 1 kW of electrical power. The system outputs were 48 V DC, 110 V AC, and 220 V AC. A cable reel with 200 m of power cable was used to provide power from the trailer to a remote location. The cable reel was installed on a small trailer. The reel was powered to provide low to no tension deployment of the cable. The cable was connected to the 220 V AC output of the power system trailer. The power was then converted back to 110 V AC on the cable deployment trailer for use at the remote site. The Scout lunar rover demonstration vehicle was used to tow the cable trailer and deploy the power cable. This deployment was performed under a number of operational scenarios, manned operation, remote operation and tele-robotically. Once deployed, the cable was used to provide power, from the power system trailer, to run various operational tasks at the remote location.

Colozza, Anthony; Jakupca, Ian; Mintz, Toby; Herlacher, Mike; Hussey, Sam

2012-01-01

163

Harmonics in DC to AC converters of single phase uninterruptible power supplies  

Microsoft Academic Search

Single phase uninterruptible power supplies (UPS) employ an inverter for DC to AC conversion. Advanced inverters consist of a full bridge transistor topology and an LC filter. An optimal inverter performance can be achieved if the output voltage is controlled by unipolar pulse width modulation (PWM). The paper describes the influence of the unipolar PWM on the voltages and the

H. Van der Broeck; M. Miller

1995-01-01

164

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

165

Microprocessor-based random PWM schemes for DC-AC power conversion  

SciTech Connect

Two classes of microprocessor-based random PWM (RPWM) real-time schemes for dc-ac power conversion are compared and evaluated. Performance of the RPWM schemes based on the mathematical and logical approaches is examined. The proposed schemes exhibit excellent harmonic content with all low and high-order harmonics suppressed and are suitable for both MOSFET and IGBT inverters.

Hui, S.Y.R. [Univ. of Sydney, New South Wales (Australia). Dept. of Electrical Engineering] [Univ. of Sydney, New South Wales (Australia). Dept. of Electrical Engineering; [City Univ. of Hong Kong, Kowloon (Hong Kong). Dept. of Electronic Engineering; Oppermann, I.; Sathiakumar, S. [Univ. of Sydney, New South Wales (Australia). Dept. of Electrical Engineering] [Univ. of Sydney, New South Wales (Australia). Dept. of Electrical Engineering

1997-03-01

166

Electromagnetic interference (EMI) design considerations for a high power AC\\/DC converter  

Microsoft Academic Search

This paper discusses some EMC design aspects for a high power AC\\/DC rectifier, and attempts to present some design guidelines to the rectifiers with the same topology. The major EMI noise sources are identified, and the countermeasures to reduce the level of the noise emissions are proposed. Both conducted and radiated emission tests on the designed rectifier meet CISPR class

Qing Chen

1998-01-01

167

Power spectrum of hadronic multiparticle rapidity distributions  

NASA Astrophysics Data System (ADS)

We discuss issues that arise in studying the power spectrum of rapidity histograms. These questions exist because the correlation functions are typically nontranslation invariant and confined to a finite kinematical interval. It is noted that the event density ?^ referred and normalized to the average single-particle density ?1, leads to (normalized) factorial cumulant bin moments dependent only on the k parameter appearing in the special case of the negative-binomial distribution. An averaged two-particle correlation function is proposed to implement the purpose of the usual Wiener-Khinchin theorem. We then generalize the bin-averaged factorial-moment technique and strip-domain moment approaches to encompass power-spectra methods. The latter connect naturally to the correlation dimensions of fractal sets and evade the problems of nonstationarity at the price of increased computational complexity. Numerical examples of chaotic time series are used to generate data. Their power spectra possess distinct properties in Gaussian and intermittent dynamics. Event averaging smooths out the power spectrum of the Gaussian dynamics, whereas the nontrivial dynamical fluctuations survive the same averaging. We argue that statistically independent events can be generated by uniformly reshuffling the rapidity histograms only if fluctuations themselves are dominantly statistical. In the presence of strongly intermittent dynamical fluctuations, correlations may exist between different events when the event points are generated by a deterministic map. In the Appendix we give the recipe for generalizing the Wiener-Khinchin theorem to calculate the power spectrum of higher-order correlations.

Carruthers, P.; Hakiog¯lu, T.

1992-06-01

168

Test report light duty utility arm power distribution system (PDS)  

SciTech Connect

The Light Duty Utility Arm (LDUA) Power Distribution System has completed vendor and post-delivery acceptance testing. The Power Distribution System has been found to be acceptable and is now ready for integration with the overall LDUA system.

Clark, D.A.

1996-03-04

169

Pulse width and pulse frequency modulation pattern controlled ZVS inverter type AC-DC power converter with lowered utility AC grid side harmonic current components for magnetron drive  

Microsoft Academic Search

The grid voltage of commercial utility power source in Japan and USA is 100 V, but in China and European countries, it is 200 V. In recent years, in Japan, 200 V output single-phase three-wire power systems have begun to be used for high power applications. In 100 V utility AC power applications and systems, an active voltage clamped quasi-resonant

M. Ishitobi; S. Moisseev; L. Gamage; M. Nakaoka; D. Bessyo; H. Omori

2002-01-01

170

AC Loss of Ripple Current in Superconducting DC Power Transmission Cable  

NASA Astrophysics Data System (ADS)

As a method of largely reducing the transmission loss in the electric power grid, superconducting direct current (DC) power transmission cable has been investigated. Using superconducting DC power transmission cables, large amounts of current and energy can be transferred compared to conventional copper cables. In this case, an alternating current (AC) is converted to DC and superposed AC which is known as ripple current, and the energy loss by the ripple current is generated. Therefore it is desired to estimate the energy loss density for the case of DC current and superposed AC current for a design of DC transmission cable system. In this study, the hysteresis loss for DC current of 2 kA rectified from 60 Hz alternating current is calculated using the Bean model, and coupling loss was also estimated. The diameter of the cable was 40 mm. The ripple currents generated by multi-pulse rectifiers, 6-pulse, 12-pulse, and 24-pulse were considered. It is found that the total AC loss including the hysteresis loss and the coupling loss is considerably smaller than the supposed heat loss of 0.5 W/m which is obtained with a newly developed cable.

Yoshitomi, K.; Otabe, E. S.; Vyatkin, V. S.; Kiuchi, M.; Matsushita, T.; Hamabe, M.; Yamaguchi, S.; Inada, R.

171

SuperPower's Second Generation HTS Conductor Design for Stability and Low AC Losses  

NASA Astrophysics Data System (ADS)

SuperPower is developing a conductor design for improved mechanical properties, quench stability, and low ac losses. Coated conductors are typically 12 mm wide with a few microns of silver overlayer. SuperPower's design modifies such base conductor designs into geometries more suited for practical applications. Wide conductors are slit into 4 mm wide tapes, in particular for cable applications, but also to reduce ac losses. After slitting, the conductor is stabilized with approximately 20 microns of surround copper stabilizer, completely encapsulating the conductor and providing a hermetic seal. Other advantages of the surround copper stabilizer configuration are rounded edges for dielectric integration and superior over-current handling capability (9X critical current with 300 ms wide pulses). Prototype 1 m cables made by Sumitomo Electric using this practical conductor showed total ac losses under 0.4 W/kA-m. To further reduce ac losses, especially for high frequency applications of the military, SuperPower's conductor design involves striating the current-carrying layers by a photolithography process. Several racetrack coils made with our practical coated conductors have been provided to Rockwell Automation for use in a demonstration motor. Recent results of our practical coated conductor will be discussed.

Hazelton, D. W.; Xie, Y. Y.; Qiao, Y.; Zhang, E.; Selvamanickam, V.

2006-03-01

172

Distributed Power Electronics for PV Systems (Presentation)  

SciTech Connect

An overview of the benefits and applications of microinverters and DC power optimizers in residential systems. Some conclusions from this report are: (1) The impact of shade is greater than just the area of shade; (2) Additional mismatch losses include panel orientation, panel distribution, inverter voltage window, soiling; (3) Per-module devices can help increase performance, 4-12% or more depending on the system; (4) Value-added benefits (safety, monitoring, reduced design constraints) are helping their adoption; and (5) The residential market is growing rapidly. Efficiency increases, cost reductions are improving market acceptance. Panel integration will further reduce price and installation cost. Reliability remains an unknown.

Deline, C.

2011-12-01

173

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

SciTech Connect

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.

Ning, Puqi [ORNL

2012-01-01

174

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

NASA Technical Reports Server (NTRS)

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.

Burrows, Linda M.; Hansen, Irving G.

1992-01-01

175

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

NASA Astrophysics Data System (ADS)

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.

Burrows, Linda M.; Hansen, Irving G.

176

Control and supervisory system for power distribution equipment  

Microsoft Academic Search

A control and supervisory system for power distribution equipment is described including a plurality of terminal control devices each controlling a corresponding power distribution device connected therewith, each of the terminal control devices comprising: control instruction means in each terminal device operable to generate and output a control command for controlling the plurality of power distribution devices, the control command

Ichiro Arinobu; Hirohisa Mizuhara; Yasuhiro Ishii; Katsuya Sakai; Hiromitsu. Takahashi

1993-01-01

177

A new method of linear control for optimum transfer of power from a solar cell array to the distribution network  

NASA Astrophysics Data System (ADS)

The paper describes a new method of linear control for transfer of optimum power from a Solar Cell Array (SCA) to the distribution network. It is shown that the current corresponding to the optimum power varies almost linearly with the level of illumination. By connecting a storage battery in parallel to the SCA, the charging current to the battery is continuously adjusted by sensing the ilumination level and current simultaneously. Variation of the charging current keeps the operating point on the optimum power locus. In the ac distribution network the power is to be fed through a current-source inverter and a step up/down transformer.

Ray, G. C.; Jha, R.

1984-08-01

178

Control and Implementation of a Matrix-Converter-Based AC Ground Power-Supply Unit for Aircraft Servicing  

Microsoft Academic Search

This paper deals with the design, control, and implementation of a three-phase ground power-supply unit for aircraft servicing. Instead of a classical back-to-back converter configuration, a three-phase direct ac-ac (matrix) converter has been used as the power conditioning core of the power supply, working in conjunction with input and output LC filters. An optimized control system in the ABC frame

Saúl López Arevalo; Pericle Zanchetta; Patrick W. Wheeler; Andrew Trentin; Lee Empringham

2010-01-01

179

Study of Structure of Co-axial Multi-layered HTS Power Cable based on Low AC Loss using Efficient 3-D FEM Analysis  

NASA Astrophysics Data System (ADS)

Controlling the current distribution in each layer of a co-axial multi-layered high-T c superconducting (HTS) cable uniformly is important in order to realize a compact and large capacity HTS power cable. The phenomenon of current imbalance should be exactly investigated by the analysis, because the current imbalance causes an increase of AC loss. In this paper, 3-D finite element analysis taking account of the nonlinear E-J characteristic is carried out in order to study the AC loss of a co-axial multi-layered HTS power cable with shield layers. The analysis region is considerably reduced by modeling spirally wound superconducting tapes as conductors having an anisotropic conductivity and using the periodic boundary condition. By using this model, AC transport characteristics of the co-axial three-layers cable (composed of two conductor layers and one shield layer) are studied, and the AC loss is investigated. The structure with low AC loss is also discussed.

Takata, Naoki; Miyagi, Daisuke; Takahashi, Norio; Torii, Shinji

180

Measurement of power frequency AC current using FBG and GMM  

Microsoft Academic Search

There is a potential demand for optical current instrument transformer (OCT) in power industry. In the past two decades, R&D on OCT was focused on Faraday effect based technology. As a sensing technology, Fiber Bragg grating (FBG) was more and more attractive recently. For OCT, FBG and giant magnetostrictive material (GMM) based technology will be another choice. In this paper,

Zhao Hong I; Xiong Yanling; Zhang Jian; Wang Shurong

2005-01-01

181

Design of a Norm-Bounded LQG Controller for Power Distribution Networks with Distributed Generation  

E-print Network

Design of a Norm-Bounded LQG Controller for Power Distribution Networks with Distributed Generation controller. I. INTRODUCTION The interconnection of small scale generation unit to the power distribution future. Traditional distribution networks were not originally designed to connect power generation

Pota, Himanshu Roy

182

DC/AC Student Guide: Solar Energy Power System  

NSDL National Science Digital Library

The purpose of this lab is to be able to measure and calculate basic values such as voltage, current, power, and efficiencies for a power system. Alternative energy is a hot topic these days and much emphasis is being placed on being "green." A "green" system is one that was intentionally designed with high-energy efficiency in mind and also that it be more environmental friendly that previous systems. As time passes more and more alternative energy systems will be placed "on-line." A technician must have the skills to measure such systems and determine if components are in need of replacement and if the systems are operating within operating specifications. Users must create a free account to download this resource.

2014-08-28

183

Improved SCR ac Motor Controller for Battery Powered Urban Electric Vehicles  

NASA Technical Reports Server (NTRS)

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.

Latos, T. S.

1982-01-01

184

Power System Concepts for the Lunar Outpost: A Review of the Power Generation, Energy Storage, Power Management and Distribution (PMAD) System Requirements and Potential Technologies for Development of the Lunar Outpost  

NASA Technical Reports Server (NTRS)

This paper will review potential power system concepts for the development of the lunar outpost including power generation, energy storage, and power management and distribution (PMAD). In particular, the requirements of the initial robotic missions will be discussed and the technologies considered will include cryogenics and regenerative fuel cells (RFC), AC and DC transmission line technology, high voltage and low voltage power transmission, conductor materials of construction and power beaming concepts for transmitting power to difficult to access locations such as at the bottom of craters. Operating conditions, component characteristics, reliability, maintainability, constructability, system safety, technology gaps/risk and adaptability for future lunar missions will be discussed for the technologies considered.

Khan, Z.; Vranis, A.; Zavoico, A.; Freid, S.; Manners, B.

2006-01-01

185

Distributed algorithms for monitoring and control of electric power transmission and distribution systems  

Microsoft Academic Search

The benefits of distributed computing systems are massively increased computing power and improved reliability. Distributed computing systems are particularly attractive for monitoring and control of large-scale electric power transmission and distribution systems. In this dissertation two aspects of distributed computing have been investigated. First, a distributed software model for the implementation of network security functions in energy management systems is

Neyer

1989-01-01

186

AC system stability analysis and assessment for Shipboard Power Systems  

E-print Network

.Sc., Zhejiang University Chair of Advisory Committee: Dr. Karen L. Butler-Purry The electric power systems in U.S. Navy ships supply energy to sophisticated systems for weapons, communications, navigation and operation. The reliability and survivability... me in my entire education. You always trust me in all my endeavors and motivate me to do my best. Your love without end is always the source of my strength. I thank my advisor, Dr. Karen Butler-Purry, for her patience, guidance and support. I...

Qi, Li

2006-04-12

187

Patch Network for Power Allocation and Distribution in Smart Materials  

NASA Technical Reports Server (NTRS)

The power allocation and distribution (PAD) circuitry is capable of allocating and distributing a single or multiple sources of power over multi-elements of a power user grid system. The purpose of this invention is to allocate and distribute power that is collected by individual patch rectennas to a region of specific power-user devices, such as actuators. The patch rectenna converts microwave power into DC power. Then this DC power is used to drive actuator devices. However, the power from patch rectennas is not sufficient to drive actuators unless all the collected power is effectively used to drive another group by allocation and distribution. The power allocation and distribution (PAD) circuitry solves the shortfall of power for devices in a large array. The PAD concept is based on the networked power control in which power collected over the whole array of rectennas is allocated to a sub domain where a group of devices is required to be activated for operation. Then the allocated power is distributed to individual element of power-devices in the sub domain according to a selected run-mode.

Golembiewski, Walter T.

2000-01-01

188

Energy and power fluctuations in ac-driven coherent conductors  

NASA Astrophysics Data System (ADS)

Using a scattering matrix approach we study transport in coherent conductors driven by a time-periodic bias voltage. We investigate the role of electron-like and hole-like excitations created by the driving in the energy current noise and we reconcile previous studies on charge current noise in these kinds of systems. The energy noise reveals additional features due to electron-hole correlations. These features should be observable in power fluctuations. In particular, we show results for the case of a harmonic and biharmonic driving and of Lorentzian pulses applied to a two-terminal conductor, addressing recent experiments [Gabelli and Reulet, Phys. Rev. B 87, 075403 (2013), 10.1103/PhysRevB.87.075403 and Dubois et al., Nature (London) 502, 659 (2013), 10.1038/nature12713].

Battista, Francesca; Haupt, Federica; Splettstoesser, Janine

2014-08-01

189

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

PubMed

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

Dash, P K; Nayak, N

2014-07-01

190

Pulse Width and Pulse Frequency Modulation Pattern Controlled Active Clamp ZVS Inverter Link AC-DC Power Converter Utility AC Side Active Power Filtering Function for Consumer Magnetron Driver  

Microsoft Academic Search

The grid voltage of commercial utility power source in Japan and USA is 100 rms, but in China and European countries, it is 200 Vrms. In recent years, in Japan 200 Vrms out putted single phase three wire system begins to be used for high power applications. In 100 Vrms utility AC power applications and systems, an active voltage clamped

M. Nakaoka; B. Saha; Sang Pil Mun; T. Mishima; Soon Kurl Kwon

2007-01-01

191

Digitally-Signed Distribution Power Lines: A Solution Which Makes Distribution Grid Intelligent  

Microsoft Academic Search

Based on broadband over power line (BPL) infrastructure and transmission control protocol\\/internet protocol (TCP\\/IP), we propose a novel system, which can cover many of the existing challenges in distribution power systems and make distribution grid more intelligent. This solution offers a unified and efficient data exchange platform for many distribution power system applications such as access to up-to-date distribution power

Behzad Daemi; Ali Abdollahi; Babak Amini; Farhad Matinfar

2010-01-01

192

Optimal distributed power generation under network load constraints  

E-print Network

Optimal distributed power generation under network load constraints Marjan van den Akker Gabri.089 3508 TB Utrecht The Netherlands #12;OPTIMAL DISTRIBUTED POWER GENERATION UNDER NETWORK LOAD CONSTRAINTS, mainly because of the development of novel components for decentral power generation (solar panels, small

Utrecht, Universiteit

193

FUTURE POWER GRID INITIATIVE Modeling of Distributed Energy  

E-print Network

FUTURE POWER GRID INITIATIVE Modeling of Distributed Energy Resources in the Smart Grid OBJECTIVE of the aggregated models includes the following steps: » modeling of the individual distributed resources (power/C load power consumption for different house types, as a function of the frequency of Tset, (amplitude

194

Low power distributed MAC for ad hoc sensor radio networks  

Microsoft Academic Search

Targeted at multi-hop wireless sensor networks, a set of low power MAC design principles have been proposed, and a novel ultra-low power MAC is designed to be distributed in nature to support scalability, survivability and adaptability requirements. Simple CSMA and spread spectrum techniques are combined to trade off bandwidth and power efficiency. A distributed algorithm is used to do dynamic

Chunlong Guo; Lizhi Charlie Zhong; J. M. Rabaey

2001-01-01

195

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

NASA Technical Reports Server (NTRS)

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).

Burrows, Linda M.; Hansen, Irving G.

1992-01-01

196

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

SciTech Connect

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. Beyond 7 days, only a few simple actions are needed to cope with the SBO for an indefinite amount of time. The operation of the ICS as the primary success path for mitigation of an SBO, allows for near immediate plant restart once power is restored. (authors)

Barrett, A. J.; Marquino, W. [New Plants Engineering, GE Hitachi Nuclear Energy, M/CA 75, 3901 Castle Hayne Road, Wilmington, NC 28402 (United States)

2012-07-01

197

Voltage Control of Distribution Networks with Distributed Generation using Reactive Power  

E-print Network

Voltage Control of Distribution Networks with Distributed Generation using Reactive Power levels. However, with significant penetration of distributed generation, the power flows may become with power flows and voltages determined by the generation as well as load. Hence, there are dramatic changes

Pota, Himanshu Roy

198

Design and analysis of a simpler DC to AC power transfer circuit for residential size photovoltaic panels  

Microsoft Academic Search

The evolution of photovoltaic (PV) based power generation systems for residential applications has been hindered by the high cost required to operate in a nonisolated mode with respect to the electric power grid. The inverter-type circuits used by some utilities to interface PV energy with the AC power grid are prohibitively expensive for residential use. Thus, in residential applications, the

F. Wicks; J. P. Martino

1996-01-01

199

A power quality transformer for feeding critical loads  

Microsoft Academic Search

In this paper a new single phase distribution transformer concept is proposed to improve power quality for critical loads. The secondary of the proposed transformer is composed of two windings, one of them equipped with a power electronic ac-ac converter. With the choice of proper turns ratio and the design of the PWM ac-ac converter, the proposed transformer has the

E. C. Aeloiza; P. N. Enjeti; L. Palma

2003-01-01

200

Application of microprocessor-based controls in an ac/dc power conversion system  

NASA Astrophysics Data System (ADS)

A description is presented of the application of a microprocessor-based control system in an ac/dc power converter (or inverter). This control system was developed as one of the tasks in a program related to the application of power converters in a utility battery storage system. The program had the objective to design a system in which the microprocessor performs the supervisory control functions of a power converter, and provides closed-loop control of voltage and current by control of the thyristor gating pulses. Attention is given to a system description, the microprocessor-controlled thyristor gating, and the microprocessor closed-loop design. The reported investigation demonstrates the potential usefulness of a microprocessor-based control in power conversion systems, and provides a good base for continued exploration of microprocessor-based products and equipment.

Kovalsky, L. J.

201

Automation in the Space Station module power management and distribution Breadboard  

NASA Technical Reports Server (NTRS)

The Space Station Module Power Management and Distribution (SSM/PMAD) Breadboard, located at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, models the power distribution within a Space Station Freedom Habitation or Laboratory module. Originally designed for 20 kHz ac power, the system is now being converted to high voltage dc power with power levels on a par with those expected for a space station module. In addition to the power distribution hardware, the system includes computer control through a hierarchy of processes. The lowest level process consists of fast, simple (from a computing standpoint) switchgear, capable of quickly safing the system. The next level consists of local load center processors called Lowest Level Processors (LLP's). These LLP's execute load scheduling, perform redundant switching, and shed loads which use more than scheduled power. The level above the LLP's contains a Communication and Algorithmic Controller (CAC) which coordinates communications with the highest level. Finally, at this highest level, three cooperating Artificial Intelligence (AI) systems manage load prioritization, load scheduling, load shedding, and fault recovery and management. The system provides an excellent venue for developing and examining advanced automation techniques. The current system and the plans for its future are examined.

Walls, Bryan; Lollar, Louis F.

1990-01-01

202

OPTIMAL DISTRIBUTED POWER GENERATION UNDER NETWORK LOAD CONSTRAINTS,  

E-print Network

OPTIMAL DISTRIBUTED POWER GENERATION UNDER NETWORK LOAD CONSTRAINTS, MARJAN VAN DEN AKKER, GABRI of novel components for decentral power generation (solar panels, small wind turbines and heat pumps the power consumption and decentral power generation are considered as stochastic variables, which

Frank, Jason

203

A Survey of Mobile Robots for Distribution Power Line Inspection  

Microsoft Academic Search

The purpose of this paper is to present the most important achievements in the field of distribution power line inspection by mobile robots. Stimulated by the need for fast, accurate, safe and low-cost power line inspection, which would increase the quality of power delivery, the field of automated power line inspection has witnessed rapid development over the last decade. This

Jaka Katrasnik; Franjo Pernus

2010-01-01

204

Evolution of power law distributions in science and society.  

PubMed

Power law distributions have been observed in numerous physical and social systems; for example, the size distributions of particles, aerosols, corporations, and cities are often power laws. Each system is an ensemble of clusters, comprising units that combine with or dissociate from the cluster. Constructing models and investigating their properties are needed to understand how such clusters evolve. To describe the growth of clusters, we hypothesize that a distribution obeys a governing population dynamics equation based on a reversible association-dissociation process. The rate coefficients are considered to depend on the cluster size as power expressions, thus providing an explanation for the asymptotic evolution of power law distributions. PMID:16241617

Jeon, Young-Pyo; McCoy, Benjamin J

2005-09-01

205

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

PubMed Central

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

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

2014-01-01

206

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

PubMed

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

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

2014-01-01

207

Power Management and Distribution Trades Studies for a Deep-Space Mission Scientific Spacecraft  

NASA Technical Reports Server (NTRS)

As part of NASA's Project Prometheus, the Nuclear Systems Program, NASA GRC performed trade studies on the various Power Management and Distribution (PMAD) options for a deep-space scientific spacecraft which would have a nominal electrical power requirement of 100 kWe. These options included AC (1000Hz and 1500Hz and DC primary distribution at various voltages. The distribution system efficiency, reliability, mass, thermal, corona, space radiation levels and technology readiness of devices and components were considered. The final proposed system consisted of two independent power distribution channels, sourced by two 3-phase, 110 kVA alternators nominally operating at half-rated power. Each alternator nominally supplies 50kWe to one half of the ion thrusters and science modules but is capable of supplying the total power re3quirements in the event of loss of one alternator. This paper is an introduction to the methodology for the trades done to arrive at the proposed PMAD architecture. Any opinions expressed are those of the author(s) and do not necessarily reflect the views of Project Prometheus.

Kimnach, Greg L.; Soltis, James V.

2004-01-01

208

Dynamic model and control of AC-DC-AC voltage-sourced converter system for distributed resources  

Microsoft Academic Search

This paper introduces a dynamic model of the AC-DC-AC voltage-sourced converter (VSC) system which provides a linear relationship between the input and output variables. The model is developed in two steps. First, the exact abc frame switched model of a VSC is transformed to a Switching Reference Frame (SRF). Then, the SRF model is transformed to an appropriate dqO reference

H. Nikkhajoei; R. Iravani

2008-01-01

209

Dynamic Model and Control of AC–DC–AC Voltage-Sourced Converter System for Distributed Resources  

Microsoft Academic Search

This paper introduces a dynamic model of the ac-dc-ac voltage-sourced converter (VSC) system which provides a linear relationship between the input and output variables. The model is developed in two steps. First, the exact abc frame switched model of a VSC is transformed to a switching reference frame (SRF). Then, the SRF model is transformed to an appropriate dq0 reference

H. Nikkhajoei; R. Iravani

2007-01-01

210

Decision Support The distribution of power in the European Constitution  

E-print Network

of the permanent nations (the United States, Russia, China, the United Kingdom and France) has seven votes and eachDecision Support The distribution of power in the European Constitution E. Algaba, J.M. Bilbao *, J Abstract The aim of this paper is to analyze the distribution of voting power in the Constitution

Bilbao Arrese, Jesús Mario

211

Communication Using Pseudonoise Modulation on Electric Power Distribution Circuits  

Microsoft Academic Search

Localized communication networks for office automation, security monitoring, environmental management of buildings, computer communications, and other applications enjoy every increasing demand. This paper considers communication of data and analog message signals over electric power distribution circuits for such applications, using pseudonoise (PN) modulation. Advantages of power distribution circuits include reasonably universal coverage and easy access via a standard wall plug.

P. van der Gracht; R. W. Donaldson

1985-01-01

212

Low-cost distributed solar-thermal-electric power generation  

E-print Network

Low-cost distributed solar-thermal-electric power generation A. Der Minassians, K. H. Aschenbach discuss the technical and economic feasibility of a low-cost distributed solar-thermal-electric power conversion efficiency, the proposed system can be a cost-effective alternative to solar photovoltaic (PV

Sanders, Seth

213

Distributed Power Generation: Requirements and Recommendations for an ICT Architecture  

E-print Network

. In the future of energy markets, the distributed energy production through wind and hydroelectric power plants distribution faces various new challenges. Most of those challenges have a strong impact on the ICT), distrib- uted generation, energy management systems (EMS) , IEC standards 1 Power Generation

Appelrath, Hans-Jürgen

214

Damping of a parallel ac-dc power system using PID power system stabilizers and rectifier current regulators  

SciTech Connect

A novel approach is presented to improve the dynamic stability of a parallel AC-DC power system. The developed scheme employs a proportional-integral-derivative (PID) power system stabilizer (PSS) and a PID rectifier current regulator (RCR) to enhance the damping for the electromagnetical mode of the system. The parameters of the proposed PID controllers are determined using a unified approach based on modal control theory. Eigenvalue analyses are performed for the system under various operating conditions in order to compare the damping effects provided by the two different control schemes. To demonstrate the effectiveness of the proposed damping schemes under disturbance conditions simulated dynamic response tests based on a nonlinear system model are also performed.

Hsu, Y.Y.; Wang, L. (Dept. of Electrical Engineering, National Taiwan Univ., Taipei (TW))

1988-09-01

215

Method and control for maintaining optimum performance of hvdc power transmission systems at rectifier end during ac system fault  

Microsoft Academic Search

A new and improved control subassembly for hvdc power converters and method of its use during transient faults affecting the ac system employed in the hvdc power transmission system are discussed. The control assures the presence of adequate firing and commutating voltages across the respective hvdc thyristor valves during selected intervals of the alternating current periods of the respective phases.

Leete

1979-01-01

216

An Analysis of Sub Sea Electric Power Transmission Techniques from DC to AC 50\\/60 Hz and Beyond  

Microsoft Academic Search

In the past decade, the significant improvements in high speed, high voltage transistor technology enabled the design of more sophisticated sub sea electrical power transmission systems. This is the case of the power-electronics-based single wire DC and high frequency AC transmission systems that appeared as alternatives to the traditional three phase transmission systems. Although such advanced alternatives have been employed

Michael C. Wrinch; M. A. Tomim; J. Marti

2007-01-01

217

Effect of leakage transformer on laser power and mode pattern of CO 2 laser excited by 60 Hz AC discharges  

Microsoft Academic Search

The 60Hz AC discharges generated by a leakage transformer instead of an isolation one, which is usually used in the power supply of DC CO2 laser, are employed as a pumping source in this experiment. The laser performance characteristics as functions of pressure and discharge current have been investigated. The maximum laser power is about 40W at conditions of 18Torr

Dong-Hoon Lee; Hyun-Ju Chung; Hee-Je Kim

1999-01-01

218

Inverter power module with distributed support for direct substrate cooling  

DOEpatents

Systems and/or methods are provided for an inverter power module with distributed support for direct substrate cooling. An inverter module comprises a power electronic substrate. A first support frame is adapted to house the power electronic substrate and has a first region adapted to allow direct cooling of the power electronic substrate. A gasket is interposed between the power electronic substrate and the first support frame. The gasket is configured to provide a seal between the first region and the power electronic substrate. A second support frame is adapted to house the power electronic substrate and joined to the first support frame to form the seal.

Miller, David Harold (San Pedro, CA); Korich, Mark D. (Chino Hills, CA); Ward, Terence G. (Redondo Beach, CA); Mann, Brooks S. (Redondo Beach, CA)

2012-08-21

219

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

220

LIMITED POWER BURSTS IN DISTRIBUTED MODELS OF NUCLEAR REACTORS  

E-print Network

LIMITED POWER BURSTS IN DISTRIBUTED MODELS OF NUCLEAR REACTORS M. V. Bazhenov and E. F. Sabaev UDC employed for analyzing reactor dynamics. Equations of this type are used for analyzing the stability of the reactor power, etc. Among these problems the question of the boundedness of reactor power bursts

Bazhenov, Maxim

221

Automation of Space Station module power management and distribution system  

NASA Technical Reports Server (NTRS)

Viewgraphs on automation of space station module (SSM) power management and distribution (PMAD) system are presented. Topics covered include: reasons for power system automation; SSM/PMAD approach to automation; SSM/PMAD test bed; SSM/PMAD topology; functional partitioning; SSM/PMAD control; rack level autonomy; FRAMES AI system; and future technology needs for power system automation.

Bechtel, Robert; Weeks, Dave; Walls, Bryan

1990-01-01

222

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)

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.

Kraft, L. Alan; Kankam, M. David

1991-01-01

223

AC Resonant charger with charge rate unrelated to primary power frequency  

DOEpatents

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.

Watson, Harold (Torrance, CA)

1982-01-01

224

A Kalman filtering based control scheme for the improvement of dynamic performance of an AC/DC power system  

NASA Astrophysics Data System (ADS)

In this dissertation, two major accomplishments are achieved. First, the feasibility of a proposed Wyoming to California HVDC system having the ratings of 1000 MW, ±500 kV, 2 kA, 860 miles and 12-pulse bipolar lines is shown for exporting Wyoming's electrical power resources to the heavy loaded western states. The second and the main objective of this dissertation is the development of a Kalman filtering (KF) based control scheme applied to an ac/dc power system. It is shown that the use KF algorithm to estimate some of the system states and utilizing them in a proportional Integral (PI) controller which has a better performance for this specific control scheme have resulted in a better dynamic performance of the proposed system. A set of case studies has shown that the system dynamic performance is improved for most of the contingencies. Ac and dc noisy voltage and current measurements received from the simulated ac/dc power system are sent to the KF estimation algorithm. The noise-separated best estimates of measurable states are computed and sent to a PI controller-based current and firing angle control subsections in order to provide a set of optimum thyristor firing angles for both converter stations during and after contingencies until the normal operation is reached. To evaluate the dynamic performance of the system with the KF algorithm, the model is simulated by a well-known digital simulation package, Electromagnetic Transients DC Program (PSCAD/EMTDC) of Manitoba HVDC Research Center. To apply the KF algorithm, a general, linearized, state-space model of the proposed ac/dc system, appropriate for analyzing both the KF and the electromagnetics transients, is derived first. The derived model enables the representation of an ac power system with two ac sources and one HVDC line with a parallel ac line connecting the two systems. It is shown that system eigenvalues of the discretized system model for a normal operating point are inside the unit circle that enables a stable operation. It is also shown that the system is controllable and observable for that specific point. The severity of a three-phase short circuit in the proposed ac/dc system is greatly reduced due to the HVDC link. One of the aims of this dissertation was to show that the addition of a parallel dc tie into an existing ac line resulted in dynamic performance improvement of the entire ac system, particularly during and after contingencies. It is also shown that a combination of the KF algorithm and PI control provides a stable recovery of the ac/dc system after a set of contingencies.

Pecen, Recayi

225

Distributed Power Network Co-Design with On-Chip Power Supplies and Decoupling Capacitors  

E-print Network

Distributed Power Network Co-Design with On-Chip Power Supplies and Decoupling Capacitors Selc¸uk K computationally complex. The rising number of on-chip power supplies and intentional decoupling capacitors network. Inter- actions among the on-chip power supplies, decoupling capacitors, and load circuitry

Friedman, Eby G.

226

Statistical analyses support power law distributions found in neuronal avalanches.  

PubMed

The size distribution of neuronal avalanches in cortical networks has been reported to follow a power law distribution with exponent close to -1.5, which is a reflection of long-range spatial correlations in spontaneous neuronal activity. However, identifying power law scaling in empirical data can be difficult and sometimes controversial. In the present study, we tested the power law hypothesis for neuronal avalanches by using more stringent statistical analyses. In particular, we performed the following steps: (i) analysis of finite-size scaling to identify scale-free dynamics in neuronal avalanches, (ii) model parameter estimation to determine the specific exponent of the power law, and (iii) comparison of the power law to alternative model distributions. Consistent with critical state dynamics, avalanche size distributions exhibited robust scaling behavior in which the maximum avalanche size was limited only by the spatial extent of sampling ("finite size" effect). This scale-free dynamics suggests the power law as a model for the distribution of avalanche sizes. Using both the Kolmogorov-Smirnov statistic and a maximum likelihood approach, we found the slope to be close to -1.5, which is in line with previous reports. Finally, the power law model for neuronal avalanches was compared to the exponential and to various heavy-tail distributions based on the Kolmogorov-Smirnov distance and by using a log-likelihood ratio test. Both the power law distribution without and with exponential cut-off provided significantly better fits to the cluster size distributions in neuronal avalanches than the exponential, the lognormal and the gamma distribution. In summary, our findings strongly support the power law scaling in neuronal avalanches, providing further evidence for critical state dynamics in superficial layers of cortex. PMID:21720544

Klaus, Andreas; Yu, Shan; Plenz, Dietmar

2011-01-01

227

Power law tails in the Italian personal income distribution  

Microsoft Academic Search

We investigate the shape of the Italian personal income distribution using microdata from the Survey on Household Income and Wealth, made publicly available by the Bank of Italy for the years 1977–2002. We find that the upper tail of the distribution is consistent with a Pareto-power law type distribution, while the rest follows a two-parameter lognormal distribution. The results of

Fabio Clementi; Mauro Gallegati

2005-01-01

228

Single-stage power factor correction ac-dc converter based on continuous input current charge-pump topologies  

Microsoft Academic Search

This paper presents a new single-stage power factor corrected (PFC) AC-DC converter. The topology is based on CIC-CPPFC (continuous input current charge-pump power factor correction) technique, achieving continuous conduction mode (CCM) input current with high power factor and reduced current ripple by using a coupled inductor, meeting IEC 61000-3-2 regulations for wide load range without additional input filter. The converter

Cícero S. Postiglione; Arnaldo J. Perin; Claudinor B. Nascimento

2008-01-01

229

A Three-Phase Unity Power Factor Single-Stage AC–DC Converter Based on an Interleaved Flyback Topology  

Microsoft Academic Search

This paper presents the design and implementation of a three-phase unity-power-factor single-stage ac-dc converter based on an interleaved flyback topology. The primary market target of the converter is within the telecommunications industry where it supplies high-quality dc power to the telecom loads and performs high-capacity battery charging while providing zero har- monic emission and unity power factor to the utility

Bunyamin Tamyurek; David A. Torrey

2011-01-01

230

Modeling the Effect of Hurricanes on Power Distribution Systems  

E-print Network

There are many calamitous events such as earthquakes, hurricanes, tsunamis etc. that occur suddenly and cause great loss of life, damage, or hardship. Hurricanes cause significant damage to power distribution systems, resulting in prolonged customer...

Chanda, Suraj

2012-10-19

231

99. POWER DISTRIBUTION UNITS FOR BATTERIES AND RECTIFIERS, NORTHEAST SIDE ...  

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

99. POWER DISTRIBUTION UNITS FOR BATTERIES AND RECTIFIERS, NORTHEAST SIDE OF LANDLINE INSTRUMENTATION ROOM (106), LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

232

Space Station Freedom power management and distribution system design  

NASA Technical Reports Server (NTRS)

The design is described of the Space Station Freedom Power Management and Distribution (PMAD) System. In addition, the significant trade studies which were conducted are described, which led to the current PMAD system configuration.

Teren, Fred

1989-01-01

233

Do wealth distributions follow power laws? Evidence from ‘rich lists’  

NASA Astrophysics Data System (ADS)

We use data on the wealth of the richest persons taken from the ‘rich lists’ provided by business magazines like Forbes to verify if the upper tails of wealth distributions follow, as often claimed, a power-law behaviour. The data sets used cover the world’s richest persons over 1996-2012, the richest Americans over 1988-2012, the richest Chinese over 2006-2012, and the richest Russians over 2004-2011. Using a recently introduced comprehensive empirical methodology for detecting power laws, which allows for testing the goodness of fit as well as for comparing the power-law model with rival distributions, we find that a power-law model is consistent with data only in 35% of the analysed data sets. Moreover, even if wealth data are consistent with the power-law model, they are usually also consistent with some rivals like the log-normal or stretched exponential distributions.

Brzezinski, Michal

2014-07-01

234

Energy loss analysis of an integrated space power distribution system  

NASA Technical Reports Server (NTRS)

The results of studies related to conceptual topologies of an integrated utility-like space power system are described. The system topologies are comparatively analyzed by considering their transmission energy losses as functions of mainly distribution voltage level and load composition. The analysis is expedited by use of a Distribution System Analysis and Simulation (DSAS) software. This recently developed computer program by the Electric Power Research Institute (EPRI) uses improved load models to solve the power flow within the system. However, present shortcomings of the software with regard to space applications, and incompletely defined characteristics of a space power system make the results applicable to only the fundamental trends of energy losses of the topologies studied. Accountability, such as included, for the effects of the various parameters on the system performance can constitute part of a planning tool for a space power distribution system.

Kankam, M. David; Ribeiro, P. F.

1992-01-01

235

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

236

Power Distribution System Planning with GIS Consideration  

NASA Astrophysics Data System (ADS)

This paper proposes a method for solving radial distribution system planning problems taking into account geographical information. The proposed method can automatically determine appropriate location and size of a substation, routing of feeders, and sizes of conductors while satisfying all constraints, i.e. technical constraints (voltage drop and thermal limit) and geographical constraints (obstacle, existing infrastructure, and high-cost passages). Sequential quadratic programming (SQP) and minimum path algorithm (MPA) are applied to solve the planning problem based on net price value (NPV) consideration. In addition this method integrates planner's experience and optimization process to achieve an appropriate practical solution. The proposed method has been tested with an actual distribution system, from which the results indicate that it can provide satisfactory plans.

Wattanasophon, Sirichai; Eua-Arporn, Bundhit

237

A Distributed Circuit Model for Power-Line Communications  

Microsoft Academic Search

This paper presents a computational efficient distributed circuit model for broadband power-line communications (PLC) in the frequency range of 1 to 30 MHz. The model is derived based on the full wave approach and it takes into account the mutual coupling between the power lines, the effect of the ground plane and the discontinuity along the lines (e.g., PLC line

Wu Qiong Luo; Soon Yim Tan

2007-01-01

238

ORIGINAL PAPER Undersampling power-law size distributions: effect  

E-print Network

Government 2014 Abstract The effect of undersampling on estimating the size of extreme natural hazards fromORIGINAL PAPER Undersampling power-law size distributions: effect on the assessment of extreme to account for estimation dependence between the power-law scaling exponent and the corner size parameter

239

Distributed Detection and Isolation of Topology Attacks in Power Networks  

E-print Network

Distributed Detection and Isolation of Topology Attacks in Power Networks James Weimer ACCESS addresses the issue of detecting and isolating topology attacks in power networks. A topology attack, unlike occurs when incorrect information about the network topology is transmitted to the system estimator

Johansson, Karl Henrik

240

Design of energy management system in distributed power station  

Microsoft Academic Search

This paper presents an energy management system (EMS) for a grid-interactive droop-controlled distributed power station, which adjust inverter output based on the power source. The control architecture consists of two levels of hierarchy: (1) the P\\/Q droop control method of every inverter which can manage the output power of each unit in order to avoid critical communication lines; (2) the

Zilong Yang; Chunsheng Wu; Hua Liao; Honghua Xu

2009-01-01

241

Optimal power allocation in distributed multiple-radar configurations  

Microsoft Academic Search

A performance driven power allocation scheme is proposed for target localization in widely distributed multiple-radar architectures. For a total transmitted power goal, power may be uniformly allocated among all transmit stations. This will result with a specific target location estimation mean-square error (MSE) that may be evaluated using the Cramer-Rao bound (CRB). However, in the case of target tracking, where

Hana Godrich; Athina Petropulu; H. Vincent Poor

2011-01-01

242

Controlling distributed energy constrained resources for power system ancillary services  

Microsoft Academic Search

Demand response, load control and control of distributed energy storage devices are gaining attention as mechanisms to support power system operation in “smart grids”, for example by providing ancillary services such as spinning reserves and regulation. This paper addresses some of the key open questions in developing algorithms to communicate with and control large populations of distributed resources, and borrows

Ashwin Kashyap; Duncan Callaway

2010-01-01

243

Automated fault location and diagnosis on electric power distribution feeders  

Microsoft Academic Search

This paper presents new techniques for locating and diagnosing faults on electric power distribution feeders. The proposed fault location and diagnosis scheme is capable of accurately identifying the location of a fault upon its occurrence, based on the integration of information available from disturbance recording devices with knowledge contained in a distribution feeder database. The developed fault location and diagnosis

Jun Zhu; D. L. Lubkeman; A. A. Girgis

1997-01-01

244

Distributed Control Implementation in CVG EDELCA Hydroelectric Power Plants  

Microsoft Academic Search

From its foundation, in 1963, CVG-EDELCA, has been outstanding by its notable participation in the production, transmission and distribution of electrical energy. In order to fulfil this objective, CVG-EDELCA has maintained its processes under supervisory control systems schemes with vanguard technology, reason why in the Caruachi hydroelectric power plant, a distributed architecture supervisory control system was implemented, including a new

A. R. Aray; J. L. L. Pedrique

2006-01-01

245

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

NASA Technical Reports Server (NTRS)

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.

Cormier, R.

1990-01-01

246

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

NASA Technical Reports Server (NTRS)

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.

1986-01-01

247

AC Loss of a Multi-Layer per Phase TriAxial HTS Cable with Balanced Current Distribution  

Microsoft Academic Search

Recently, high-temperature superconductor (HTS) cables have been widely studied because of their compactness and high power\\u000a capacity compared to conventional copper cables. In HTS cables, AC loss is an important issue since large losses reduce the\\u000a efficiency of the power line.\\u000a \\u000a \\u000a Among HTS cables, tri-axial cable is under intensive investigation recently, since it has a smaller amount of HTS tapes,

A. N. Ozcivan; M. Toda; N. Hu; K. Hoshino; T. Yagai; M. Tsuda; T. Hamajima

2011-01-01

248

Calculated CIM Power Distributions for Coil Design  

SciTech Connect

Excessive bed expansion and material expulsion have occurred during experiments with the 3-inch diameter Cylindrical Induction Melter (CIM). Both events were attributed in part to the high power density in the bottom of the melter and the correspondingly high temperatures there. It is believed that the high temperatures resulted in the generation of gasses at the bottom of the bed which could not escape. The gasses released during heating and the response of the bed to gas evolution depend upon the composition of the bed.

Hardy, B.J.

1999-02-17

249

AC 2009-1451: A FRAMEWORK FOR DEVELOPING A COHESIVE SET OF REMOTE LABORATORIES FOR DISTRIBUTED DISTANCE LEARNING  

E-print Network

AC 2009-1451: A FRAMEWORK FOR DEVELOPING A COHESIVE SET OF REMOTE LABORATORIES FOR DISTRIBUTED Mechanical Engineering masters in design at Georgia Tech. He is interested in working with engineering of Technology in the field of robotics and controls. As a member of the Intelligent Machine Dynamics Laboratory

250

Comparative studies of direct photovoltaic and AC rectified power supplies for battery charging  

SciTech Connect

The Clean Energy and Vehicle Research Center at the University of South Florida (USF) is operating a 20 kW (peak) photovoltaic (PV) system in which PV panels form the roof of a 12 bay carport. 4 of the 12 bays has a potential 6kW output that can be used for simultaneous computer controlled direct DC-DC charging and utility interconnection. The program has been created to evaluate the potential contribution of photovoltaics as a method for offsetting the fuel cost of electric vehicles while reducing air pollution generated by power plants, that are fueled by non-renewable sources. When charging lead acid batteries in an EV, a large percentage (22%--40%) of the charging power is lost, which raises the cost of operation. The charger losses usually include power conditioning, power factor, and heat losses, which cumulatively can range between 3%--25%. However, this loss is not a constant and can be affected by the charging process. To determine the impact that charging has on battery losses, two chargers with different power conditioning and charging algorithms will be used under controlled conditions. The battery pack is a 120V 183Ah (5 hr rate) flooded lead acid system located in a Chevy S-10 EV. The first charger (charger A) derives its power from the 6kW photovoltaic array. This charger is computer controlled and prevents gassing throughout the entire charge. This power is pure DC with no ripple. The second charger (charger B) derives its power from the 208V single phase AC grid. This power is condition through a transformer and then rectified with no filtering. The charger conducts only when the rectified voltage exceeds that of the battery pack, which results in the output consisting of current ripples. Test results will be presented to show the extent the ripple power of charger B causes losses in the battery pack, how it influences the battery temperature and the extra losses associated during the gassing phase.

Lamb, H.; Stefanakos, E.; Arbogast, T.; Smith, T. [Univ. of South Florida, Tampa, FL (United States). Clean Energy and Vehicle Research Center

1995-12-31

251

Main Power Distribution Unit for the Jupiter Icy Moons Orbiter (JIMO)  

NASA Technical Reports Server (NTRS)

Around the year 2011, the Jupiter Icy Moons Orbiter (JIMO) will be launched and on its way to orbit three of Jupiter s planet-sized moons. The mission goals for the JIMO project revolve heavily around gathering scientific data concerning ingredients we, as humans, consider essential: water, energy and necessary chemical elements. The JIM0 is an ambitious mission which will implore propulsion from an ION thruster powered by a nuclear fission reactor. Glenn Research Center is responsible for the development of the dynamic power conversion, power management and distribution, heat rejection and ION thrusters. The first test phase for the JIM0 program concerns the High Power AC Power Management and Distribution (PMAD) Test Bed. The goal of this testing is to support electrical performance verification of the power systems. The test bed will incorporate a 2kW Brayton Rotating Unit (BRU) to simulate the nuclear reactor as well as two ION thrusters. The first module of the PMAD Test Bed to be designed is the Main Power Distribution Unit (MPDU) which relays the power input to the various propulsion systems and scientific instruments. The MPDU involves circuitry design as well as mechanical design to determine the placement of the components. The MPDU consists of fourteen relays of four different variations used to convert the input power into the appropriate power output. The three phase system uses 400 Vo1ts(sub L-L) rms at 1000 Hertz. The power is relayed through the circuit and distributed to the scientific instruments, the ION thrusters and other controlled systems. The mechanical design requires the components to be positioned for easy electrical wiring as well as allowing adequate room for the main buss bars, individual circuit boards connected to each component and power supplies. To accomplish creating a suitable design, AutoCAD was used as a drafting tool. By showing a visual layout of the components, it is easy to see where there is extra room or where the components may interfere with one another. By working with the electrical engineer who is designing the circuit, the specific design requirements for the MPDU were determined and used as guidelines. Space is limited due to the size of the mounting plate therefore each component must be strategically placed. Since the MPDU is being designed to fit into a simulated model of the spacecraft systems on the JIMO, components must be positioned where they are easily accessible to be wired to the other onboard systems. Mechanical and electrical requirements provided equally important limits which are combined to produce the best possible design of the MPDU.

Papa, Melissa R.

2004-01-01

252

Flexible Active Power Control of Distributed Power Generation Systems During Grid Faults  

Microsoft Academic Search

The increasing penetration of distributed power generation into the power system leads to a continuous evolution of grid interconnection requirements. In particular, active power control will play an important role both during grid faults (low-voltage ride-through capability and controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible

Pedro Rodriguez; Adrian V. Timbus; Remus Teodorescu; Marco Liserre; Frede Blaabjerg

2007-01-01

253

Connecting an alternative energy source to the power grid by a DSP controlled DC\\/AC inverter  

Microsoft Academic Search

In times when environmental issues such as global warming and air pollution are in focus, there are more objections to the use of conventional and nuclear power stations. The use of alternative energy sources such as water turbines, solar cells and wind turbines becomes essential for producing clean energy. In this paper, a novel design of a 1 kW DC\\/AC

Yuval Beck; Bishara Bishara; Dror Medini

2005-01-01

254

Estimation in a fluctuating medium and power-law distributions  

NASA Astrophysics Data System (ADS)

We show how recent results by Bening and Korolev in the context of estimation, when linked with a classical result of Fisher concerning the negative binomial distribution, can be used to explain the ubiquity of power-law probability distributions. Beck, Cohen and others have provided plausible mechanisms explaining how power-law probability distributions naturally emerge in scenarios characterized by either finite dimension or fluctuation effects. This Letter tries to further contribute to such an idea. As an application, a new and multivariate version of the central limit theorem is obtained that provides a convenient alternative to the one recently presented in [S. Umarov, C. Tsallis, S. Steinberg, cond-mat/0603593].

Vignat, C.; Plastino, A.

2007-01-01

255

Power distribution system planning with reliability modeling and optimization  

SciTech Connect

A new approach for the systemized optimization of power distribution systems is presented in this paper. Distribution system reliability is modeled in the optimization objective function via outage costs and costs of switching devices, along with the nonlinear costs of investment, maintenance and energy losses of both the substations and the feeders. The optimization model established is multi-stage, mixed-integer and nonlinear, which is solved by a network-flow programming algorithm. A multi-stage interlacing strategy and a nonlinearity iteration method are also designed. Supported by an extensive database, the planning software tool has been applied to optimize the power distribution system of a developing city.

Tang, Y. [Siemens Power Corp., Roswell, GA (United States)] [Siemens Power Corp., Roswell, GA (United States)

1996-02-01

256

Options for Control of Reactive Power by Distributed Photovoltaic Generators  

E-print Network

High penetration levels of distributed photovoltaic(PV) generation on an electrical distribution circuit present several challenges and opportunities for distribution utilities. Rapidly varying irradiance conditions may cause voltage sags and swells that cannot be compensated by slowly responding utility equipment resulting in a degradation of power quality. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We discuss and compare via simulation various design options for control systems to manage the reactive power generated by these inverters. An important design decision that weighs on the speed and quality of communication required is whether the control should be centralized or distributed (i.e. local). In general, we find that local control schemes are capable for maintaining voltage within acceptable bounds. We consider the benefits of choosing different local variables on which to control and how the control system can be continuously tuned between robust voltage control, suitable for daytime operation when circuit conditions can change rapidly, and loss minimization better suited for nighttime operation.

Petr Sulc; Konstantin Turitsyn; Scott Backhaus; Michael Chertkov

2010-08-04

257

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

SciTech Connect

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.

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

2006-08-01

258

Hysteresis, phase transitions, and dangerous transients in electrical power distribution systems.  

PubMed

The majority of dynamical studies in power systems focus on the high-voltage transmission grids where models consider large generators interacting with crude aggregations of individual small loads. However, new phenomena have been observed indicating that the spatial distribution of collective, nonlinear contribution of these small loads in the low-voltage distribution grid is crucial to the outcome of these dynamical transients. To elucidate the phenomenon, we study the dynamics of voltage and power flows in a spatially extended distribution feeder (circuit) connecting many asynchronous induction motors and discover that this relatively simple 1+1 (space+time) dimensional system exhibits a plethora of nontrivial spatiotemporal effects, some of which may be dangerous for power system stability. Long-range motor-motor interactions mediated by circuit voltage and electrical power flows result in coexistence and segregation of spatially extended phases defined by individual motor states, a "normal" state where the motors' mechanical (rotation) frequency is slightly smaller than the nominal frequency of the basic ac flows and a "stalled" state where the mechanical frequency is small. Transitions between the two states can be initiated by a perturbation of the voltage or base frequency at the head of the distribution feeder. Such behavior is typical of first-order phase transitions in physics, and this 1+1 dimensional model shows many other properties of a first-order phase transition with the spatial distribution of the motors' mechanical frequency playing the role of the order parameter. In particular, we observe (a) propagation of the phase-transition front with the constant speed (in very long feeders) and (b) hysteresis in transitions between the normal and stalled (or partially stalled) phases. PMID:23848724

Duclut, Charlie; Backhaus, Scott; Chertkov, Michael

2013-06-01

259

The Origin of Power Law Distributions in Protein Synthesis  

NASA Astrophysics Data System (ADS)

A genetically identical bacteria population will show heterogeneous gene expression due to the stochastic nature of the protein production mechanism. Therefore, the probability distribution of the resulting protein(s) can be used to gain information about these underlying processes. The experiments of Chapman-McQuistion et. al. show that under certain circumstances the protein probability distribution has a power law form p(n) ˜n^-? at small n. Our simulations and analysis find, in agreement with work by Friedlander and Brenner, that a linear protein production rate will produce a power law distribution with the exponent depending on the amplitude of the production rate. We also find that a protein distribution generated by rare occurrences of large bursts will produce a distribution of the form p(n) ˜1/n.

Barker, Jeffrey; Yeung, Chuck; Wu, Xiao-Lun; Chapman-McQuiston, Emily

2009-03-01

260

Power-law tailed statistical distributions and Lorentz transformations  

NASA Astrophysics Data System (ADS)

The present Letter, deals with the statistical theory [G. Kaniadakis, Phys. Rev. E 66 (2002) 056125; G. Kaniadakis, Phys. Rev. E 72 (2005) 036108], which predicts the probability distribution p(E)?exp?(-I), where, I??E-??, is the collision invariant, and exp?(x)=(x+?x)1/?, with ?<1. This, experimentally observed distribution, at low energies behaves as the Maxwell-Boltzmann exponential distribution, while at high energies presents power law tails. Here we show that the function exp?(x) and its inverse ln?(x), can be obtained within the one-particle relativistic dynamics, in a very simple and transparent way, without invoking any extra principle or assumption, starting directly from the Lorentz transformations. The achievements support the idea that the power law tailed distributions are enforced by the Lorentz relativistic microscopic dynamics, like in the case of the exponential distribution which follows from the Newton classical microscopic dynamics.

Kaniadakis, G.

2011-01-01

261

Automation of the Athens (Tennessee) electric power distribution system  

SciTech Connect

A large scale distribution automation research and development project has been conducted at the Athens Utilities Board (AUB) in Athens, Tennessee. The project goal was to experiment with the integrated monitoring and control of an entire distribution system from a central distribution control center. The project was sponsored by the U.S. Department of Energy, Office of Energy Storage and Distribution, Electric Energy Systems Program and managed by the Oak Ridge National Laboratory. The experience with the distribution substation monitoring and control, feeder monitoring, voltage and reactive power (vary) control, system (or circuit) reconfiguration for emergency and maintenance situations, and load control are described. A distribution automation applications software package for assessing system configuration, and volt/var control on automated radial distribution feeders was developed and is also described. 8 refs.

Rizy, D.T.; Stovall, J.P.; Usry, G.H.

1988-01-01

262

Distributed photovoltaic generation in residential distribution systems: Impacts on power quality and anti-islanding  

NASA Astrophysics Data System (ADS)

The past few decades have seen a consistent growth of distributed PV sources. Distributed PV, like other DG sources, can be located at or near load centers and provide benefits which traditional generation may lack. However, distribution systems were not designed to accommodate such power generation sources as these sources might lead to operational as well as power quality issues. A high penetration of distributed PV resources may lead to bi-directional power flow resulting in voltage swells, increased losses and overloading of conductors. Voltage unbalance is a concern in distribution systems and the effect of single-phase residential PV systems on voltage unbalance needs to be explored. Furthermore, the islanding of DGs presents a technical hurdle towards the seamless integration of DG sources with the electricity grid. The work done in this thesis explores two important aspects of grid inte-gration of distributed PV generation, namely, the impact on power quality and anti-islanding. A test distribution system, representing a realistic distribution feeder in Arizona is modeled to study both the aforementioned aspects. The im-pact of distributed PV on voltage profile, voltage unbalance and distribution sys-tem primary losses are studied using CYMDIST. Furthermore, a PSCAD model of the inverter with anti-island controls is developed and the efficacy of the anti-islanding techniques is studied. Based on the simulations, generalized conclusions are drawn and the problems/benefits are elucidated.

Mitra, Parag

263

Power laws, discontinuities and regional city size distributions  

USGS Publications Warehouse

Urban systems are manifestations of human adaptation to the natural environment. City size distributions are the expression of hierarchical processes acting upon urban systems. In this paper, we test the entire city size distributions for the southeastern and southwestern United States (1990), as well as the size classes in these regions for power law behavior. We interpret the differences in the size of the regional city size distributions as the manifestation of variable growth dynamics dependent upon city size. Size classes in the city size distributions are snapshots of stable states within urban systems in flux. ?? 2008.

Garmestani, A.S.; Allen, C.R.; Gallagher, C.M.

2008-01-01

264

High energy-efficient and compact AC-AC converters  

Microsoft Academic Search

AC-AC converters offer much better energy efficiency than conventional two-stage power converters or inverters. This paper reports a new modular phase bank design approach of AC-AC converters that significantly reduces the size and weight of the power converter and improves the power density. The modular approach and integrated AC power modules offer a much improved design for the power circuits

Jie Chang; T. Sun; Anhua Wang

2001-01-01

265

Proposal of an Innovative Electric Power Distribution System based on Packet Power Transactions  

NASA Astrophysics Data System (ADS)

Recently, the introduction of decentralized generators, such as photovoltaic power generations, has been promoted rapidly. In the future, extensive use of PV is thought to give rise to the daytime surplus electricity, and a household will manage the surplus electricity rationally. The purpose of this research is to propose an innovative electric power distribution system based on packet power transactions. First, this paper explains distributed markets of which the price can easily reflect the geographical diversity of renewable energy availability and load curve characteristic within the local area. Second, this paper exemplifies the specific electronic circuit that makes pulse-shaped power transmission to develop the packet power distribution system. Finally, this paper shows the results of multi-agent simulations of electricity trading to evaluate the usefulness of the proposed system.

Inoue, Jun; Fujii, Yasumasa

266

Electrical Power Distribution and Control Modeling and Analysis  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the use of Electrical Power Distribution and Control (EPD&C) Modeling and how modeling can support analysis. The presentation discusses using the EASY5 model to simulate and analyze the Space Shuttle Electric Auxiliary Power Unit. Diagrams of the model schematics are included, as well as graphs of the battery cell impedance, hydraulic load dynamics, and EPD&C response to hydraulic load variations.

Fu, Johnny S.; Liffring, Mark; Mehdi, Ishaque S.

2001-01-01

267

Probability distributions of some power system reliability indices  

E-print Network

PROBABILITY DISTRIBUTIONS OF SOME POWER SYSTEM RELIABILITY INDICES A Thesis by MINH DIP (DIEP) Submitted to the Graduate College of Texas A&M University in p a r t i a l f u l f i l l m e n t of the requirement f o r the degree of MASTER... OF SCIENCE December 1978 Major Subject: E l e c t r i c a l Engineering PROBABILITY DISTRIBUTIONS OF SOME POWER SYSTEM RELIABILITY INDICES A Thesis by MINH DIP (DIEP) Approved as to s t y l e and content by: {Co-Chairman of Committee) December 1978...

Dip, Minh

1978-01-01

268

Electric power scheduling - A distributed problem-solving approach  

NASA Technical Reports Server (NTRS)

Space Station Freedom's power system, along with the spacecraft's other subsystems, needs to carefully conserve its resources and yet strive to maximize overall Station productivity. Due to Freedom's distributed design, each subsystem must work cooperatively within the Station community. There is a need for a scheduling tool which will preserve this distributed structure, allow each subsystem the latitude to satisfy its own constraints, and preserve individual value systems while maintaining Station-wide integrity.

Mellor, Pamela A.; Dolce, James L.; Krupp, Joseph C.

1990-01-01

269

Power-aware applications for scientific cluster and distributed computing  

E-print Network

The aggregate power use of computing hardware is an important cost factor in scientific cluster and distributed computing systems. The Worldwide LHC Computing Grid (WLCG) is a major example of such a distributed computing system, used primarily for high throughput computing (HTC) applications. It has a computing capacity and power consumption rivaling that of the largest supercomputers. The computing capacity required from this system is also expected to grow over the next decade. Optimizing the power utilization and cost of such systems is thus of great interest. A number of trends currently underway will provide new opportunities for power-aware optimizations. We discuss how power-aware software applications and scheduling might be used to reduce power consumption, both as autonomous entities and as part of a (globally) distributed system. As concrete examples of computing centers we provide information on the large HEP-focused Tier-1 at FNAL, and the Tigress High Performance Computing Center at Princeton University, which provides HPC resources in a university context.

David Abdurachmanov; Peter Elmer; Giulio Eulisse; Paola Grosso; Curtis Hillegas; Burt Holzman; Ruben L. Janssen; Sander Klous; Robert Knight; Shahzad Muzaffar

2014-10-22

270

Evaluation of power control concepts using the PMAD systems test bed. [Power Management and Distribution  

NASA Technical Reports Server (NTRS)

The Lewis Research Center's Power Management and Distribution (PMAD) System testbed and its use in the evaluation of control concepts applicable to the NASA Space Station Freedom electric power system (EPS) are described. The facility was constructed to allow testing of control hardware and software in an environment functionally similar to the space station electric power system. Control hardware and software have been developed to allow operation of the testbed power system in a manner similar to a supervisory control and data acquisition (SCADA) system employed by utility power systems for control. The system hardware and software are described.

Beach, R. F.; Kimnach, G. L.; Jett, T. A.; Trash, L. M.

1989-01-01

271

An improved automotive power distribution system using nonlinear resonant switch converters  

Microsoft Academic Search

An improved automotive electrical system is proposed in which the generator is a high-efficiency AC machine connected to the battery by an AC-DC converter. The electrical loads are isolated from the battery by a DC-DC converter. This will allow gradual conversion to higher battery voltage, regulation of DC distribution voltage, and multiple distribution voltage levels. In the low-voltage, high-current, high-temperature

Stephen W. Anderson; Robert W. Erickson; Ronald A. Martin

1991-01-01

272

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

NASA Astrophysics Data System (ADS)

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.

Abdollahi, Rohollah

2012-12-01

273

Load Frequency Control in Power System with Distributed Generation  

NASA Astrophysics Data System (ADS)

This paper proposes a method to improve the load frequency control in a power system with distributed generation (DG). DG is assumed to include photovoltaic generation, wind power generation, fuel cells and etc. In this paper, a simulation is performed using a microgrid model or island model that is composed of a storage system with either wind power generation or photovoltaic generation system as the DG. The effectiveness of load frequency control (LFC) using a storage system is examined using a power transmission simulator. The model for the experiment has been composed of inverter, battery, synchronous generator and load. Using this model, the comparison examination was done in respect of output setting control and the case in which the PI control was used. As a result, when the output set-point control using power demand estimation method is executed, the control characteristic is very excellent.

Yukita, Kazuto; Ota, Takuya; Fujimoto, Koji; Goto, Yasuyuki; Ichiyanagi, Katuhiro

274

Adaptive Active Power Line Harmonic Filter for Industrial and Commercial Power Distribution Systems  

Microsoft Academic Search

Harmonic disturbances caused by non-linear loads such as power switching devices often occur in the industrial and commercial power distribution systems and can damage sensitive equipment connected to the systems, causing tremendous productivity loss. This paper presents an adaptive-harmonic detection-algorithm (AHDA) active filter for effective elimination of harmonic disturbances. This filter consists of a standard power electronic inverter with state-of-the-art

F. Chen; Lin Wang; Weidong Liu; T. Mander; R. Cheung

2006-01-01

275

Adaptive D-based Active Power Line Filter for Industrial and Commercial Power Distribution  

Microsoft Academic Search

Harmonic disturbances caused by non-linear loads such as power switching devices often occur in the industrial and commercial power distribution systems and can damage sensitive equipment connected to the systems, causing tremendous productivity loss. This paper presents a novel adaptive-harmonic- detection active filter, consisting of an industry-type power electronic inverter controlled by state-of-the-art digital signal processor (DSP). This adaptive-detection DSP-based

Frank Chen; Helen Cheung; Lin Wang; Todd Mander; Weidong Liu; Richard Cheung

2007-01-01

276

Distributional Information: A Powerful Cue for Acquiring Syntactic Categories  

Microsoft Academic Search

Many theorists have dismissed a priori the idea that distributional information could play a significant role in syntactic category acquisition. We demonstrate empirically that such information provides a powerful cue to syntactic category membership, which can be exploited by a variety of simple, psychologically plausible mechanisms. We present a range of results using a large corpus of child-directed speech and

Martin Redington; Nick Chater; Steven Finch

1998-01-01

277

Pointers and linked lists in electric power distribution circuit analysis  

Microsoft Academic Search

Electric power distribution circuit analysis programs must efficiently manage a large quantity of system and equipment data. Utility engineers now wish to use integrated software packages with several functions that work efficiently and share data. The use of data structures stored in linked lists and processed through pointers is described. The pointers and linked lists compact the data storage and

R. P. Broadwater; J. C. Thompson; T. E. McDermott

1991-01-01

278

Rooftop Solar Potential Distributed Solar Power in NW  

E-print Network

Energy Data System (SEDS) #12;6/19/2013 4 0.06% 0.07% Solar As Percent of Total Energy Consumption 2010 Based State Energy Data System (includes Solar thermal and PV) 10 #12;6/19/2013 6 Using EIA 8616/19/2013 1 Rooftop Solar Potential Distributed Solar Power in NW Massoud Jourabchi June 2013 1

279

Rooftop Solar Potential Distributed Solar Power in NW  

E-print Network

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Based State Energy Data System (includes Solar1 Rooftop Solar Potential Distributed Solar Power in NW Massoud Jourabchi June 2013 1 Renewables;3 Regional Growth In Solar Energy Consumption Solar consumption both Thermal and PV h b t d i i lhas been

280

Estimation of Wind Power Potential Using Weibull Distribution  

Microsoft Academic Search

The main objective of the present study is to estimate wind power potential using the two Weibull parameters of the wind speed distribution function, the shape parameter k (dimensionless) and the scale parameter c (m\\/s). In this regard, a methodology that uses three various techniques (maximum likelihood, least squares, and method of moments) for estimating the Weibull parameters was given

Asir Genc; Murat Erisoglu; Ahmet Pekgor; Galip Oturanc; Arif Hepbasli; Koray Ulgen

2005-01-01

281

Clock and Power Distribution Networks for 3-D Integrated Circuits  

Microsoft Academic Search

Global interconnect design for three- dimensional integrated circuits is a crucial task. Despite the importance of this task, limited results related to global issues have been presented. Challenges in reliably distributing power, ground, and the clock signal within a multi-plane integrated system are discussed in this pa- per. The design of two 3-D test circuits addressing these issues is described.

Ioannis Savidis; Eby G. Friedman; Vasilis F. Pavlidis; Giovanni De Micheli

282

Electron beam machining using rotating and shaped beam power distribution  

DOEpatents

An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.

Elmer, John W. (Pleasanton, CA); O'Brien, Dennis W. (Livermore, CA)

1996-01-01

283

Electron beam machining using rotating and shaped beam power distribution  

DOEpatents

An apparatus and method are disclosed for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: (1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and (2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1,000 {micro}m (1 mm or larger), compared to the 250 {micro}m diameter of laser drilling. 5 figs.

Elmer, J.W.; O`Brien, D.W.

1996-07-09

284

Statistical Models of Power-law Distributions in Homogeneous Plasmas  

SciTech Connect

A variety of in-situ measurements in space plasmas point out to an intermittent formation of distribution functions with elongated tails and power-law at high energies. Power-laws form ubiquitous signature of many complex systems, plasma being a good example of a non-Boltzmann behavior for distribution functions of energetic particles. Particles, which either undergo mutual collisions or are scattered in phase space by electromagnetic fluctuations, exhibit statistical properties, which are determined by the transition probability density function of a single interaction, while their non-asymptotic evolution may determine the observed high-energy populations. It is shown that relaxation of the Brownian motion assumptions leads to non-analytical characteristic functions and to generalization of the Fokker-Planck equation with fractional derivatives that result in power law solutions parameterized by the probability density function.

Roth, Ilan [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

2011-01-04

285

Multi-kw dc power distribution system study program  

NASA Technical Reports Server (NTRS)

The first phase of the Multi-kw dc Power Distribution Technology Program is reported and involves the test and evaluation of a technology breadboard in a specifically designed test facility according to design concepts developed in a previous study on space vehicle electrical power processing, distribution, and control. The static and dynamic performance, fault isolation, reliability, electromagnetic interference characterisitics, and operability factors of high distribution systems were studied in order to gain a technology base for the use of high voltage dc systems in future aerospace vehicles. Detailed technical descriptions are presented and include data for the following: (1) dynamic interactions due to operation of solid state and electromechanical switchgear; (2) multiplexed and computer controlled supervision and checkout methods; (3) pulse width modulator design; and (4) cable design factors.

Berkery, E. A.; Krausz, A.

1974-01-01

286

Analysis and design of a direct AC to AC matrix converter topology  

E-print Network

with the conven- tional switching method (b)Extended waveform of the load volt- age 30 Voltage and current waveforms across the switch with the conven- tional switching method CHAPTERI INTRODUCTION A. Introduction to AC to AC Conviuter Electric utilities... generate, transmit and distribute electrical power of a fixed frequency snd voltage. Several industrial loads, such as motors, require a variable voltage, vari- able frequency or variable voltage fixed frequency power supply for their efficien op...

Choi, Sewan

2012-06-07

287

Learning geotemporal nonstationary failure and recovery of power distribution.  

PubMed

Smart energy grid is an emerging area for new applications of machine learning in a nonstationary environment. Such a nonstationary environment emerges when large-scale failures occur at power networks because of external disruptions such as hurricanes and severe storms. Power distribution networks lie at the edge of the grid, and are especially vulnerable to external disruptions. Quantifiable approaches are lacking and needed to learn nonstationary behaviors of large-scale failure and recovery of power distribution. This paper studies such nonstationary behaviors in three aspects. First, a novel formulation is derived for an entire life cycle of large-scale failure and recovery of power distribution. Second, spatial-temporal models of failure and recovery of power distribution are developed as geolocation-based multivariate nonstationary GI(t)/G(t)/? queues. Third, the nonstationary spatial-temporal models identify a small number of parameters to be learned. Learning is applied to two real-life examples of large-scale disruptions. One is from Hurricane Ike, where data from an operational network is exact on failures and recoveries. The other is from Hurricane Sandy, where aggregated data is used for inferring failure and recovery processes at one of the impacted areas. Model parameters are learned using real data. Two findings emerge as results of learning: 1) failure rates behave similarly at the two different provider networks for two different hurricanes but differently at the geographical regions and 2) both the rapid and slow-recovery are present for Hurricane Ike but only slow recovery is shown for a regional distribution network from Hurricane Sandy. PMID:24806656

Wei, Yun; Ji, Chuanyi; Galvan, Floyd; Couvillon, Stephen; Orellana, George; Momoh, James

2014-01-01

288

Application of search methods in modeling integral horsepower AC motors with microprocessor-based power electronic controllers  

Microsoft Academic Search

An optimum model is found for a three-horsepower AC motor and load controlled by a modern microprocessor-based power electronic controller. The proposed model includes the introduction of an integration term into the linear dynamics as well as two nonlinear terms, one of which depends upon user-selected parameters in the controller. The model form for a particular motor-load combination is optimized

Robert L. Drake

1997-01-01

289

Distributed algorithms for monitoring and control of electric power transmission and distribution systems  

SciTech Connect

The benefits of distributed computing systems are massively increased computing power and improved reliability. Distributed computing systems are particularly attractive for monitoring and control of large-scale electric power transmission and distribution systems. In this dissertation two aspects of distributed computing have been investigated. First, a distributed software model for the implementation of network security functions in energy management systems is proposed. Second, a theoretical framework for the development of distributed algorithms is developed. The framework is applied to some of the functions necessary for the operation of an automated power distribution system. The proposed distributed model for the software of energy management systems is based on the object-oriented methodology. A prototype implementation of the power flow function is described as a concrete example for the application of the model. Other network security functions discussed are state estimation and bad data detection. The proposed model reduces the effort of development and maintenance of large-scale energy management system software. It provides a tool for coping with the constantly increasing complexity of these software systems. A framework for the development of distributed algorithms is proposed. A special class of separable continuous constrained optimization problems is considered. A class of asynchronous iterative algorithms is developed. The solution of the separable continuous constrained optimization problem is emphasized because many problems arising in the operation of an automated distribution system can be formulated as constrained optimization problems. It is shown that these optimization problems can be solved with a set of largely independent processors which exchange a minimum of information.

Neyer, A.F.

1989-01-01

290

Automatic control system by power distribution in a power-generating reactor  

SciTech Connect

The development of the theoretical principles of construction of these systems and of sufficiently detailed nonlinear dynamic numerical models of a power-generation unit with an RBMK reactor have allowed a consistent procedure to be produced for the engineering synthesis of an (local automated control) LAC-LEP (local emergency protection) system. The LAC system facilitates the shaping and maintenance of the desired power distribution in the whole volume of the reactor. In emergency situations, the LAC-LEP system qualitatively reduces the power to a safe level and effectively suppresses the power warpings in one-half of the reactor, which are characteristic for these reactors.

Aleksakov, A.N.; Podlazov, L.N.; Ryabov, V.I.; Shevchenko, V.V.; Postnikov, V.V.

1980-12-01

291

Photovoltaic powered 20-hp DC/AC irrigation system and a 3-kW nitrogen generator  

SciTech Connect

A 25-kWp photovoltaic power system has been providing power for irrigation and crop drying since July 1977 at an agricultural field station of the University of Nebraska, located at Mead, Nebraska. The system was designed and built by Massachusetts Institute of Technology's Lincoln Laboratory under US Department of Energy sponsorship and is being operated jointly by the university and MIT Lincoln Laboratory. The system consists of a 25-kWp PV array, a battery subsystem, a power dump, an inverter, a controller and a data acquisition system. This photovoltaic power system has been used as a test facility in order to test and evaluate a variety of PV-related agricultural applications, including irrigation, crop drying and fertilizer manufacturing. Two interesting applications presently under evaluation are a 20-hp DC/AC-powered irrigation system and an on-site nitrogen fertilizer production unit.

Hopkinson, R.F.

1980-01-01

292

Efficient Macromodeling of Power Distribution Planes using Delay Extraction based Transmission Line Representation  

E-print Network

Efficient Macromodeling of Power Distribution Planes using Delay Extraction based Transmission Line, accurate broadband macromodeling of power planes is required. Prominent techniques in macromodeling power in power distribution networks (PDN) [1]. Since PDN supply power to core logic and I/O circuits, such power

Roy, Sourajeet

293

Lift-and-Project Relaxations of AC Microgrid Distribution System Planning  

E-print Network

We apply relaxation procedures to polynomial optimization problems that originate in transmission system planning, and obtain new convex formulations for the AC case. The approach is novel because the optimization is ...

Taylor, Joshua A.

2011-01-01

294

Implementation and control of grid connected AC-DC-AC power converter for variable speed wind energy conversion system  

Microsoft Academic Search

30 kW electrical power conversion system is developed for a variable speed wind turbine system. In the wind energy conversion system (WECS) a synchronous generator converts the mechanical energy into electrical energy. As the voltage and frequency of generator output vary along the wind speed change, a DC-DC boosting chopper is utilized to maintain constant DC link voltage. The input

Seung-Ho Song; Shin-il Kang; Nyeon-kun Hahm

2003-01-01

295

Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors  

NASA Technical Reports Server (NTRS)

Optoelectronic systems designed according to time-sharing scheme distribute optical power to multiple integrated-circuit-based sensors in fiber-optic networks. Networks combine flexibility of electronic sensing circuits with advantage of electrical isolation afforded by use of optical fibers instead of electrical conductors to transmit both signals and power. Fiber optics resist corrosion and immune to electromagnetic interference. Sensor networks of this type useful in variety of applications; for example, in monitoring strains in aircraft, buildings, and bridges, and in monitoring and controlling shapes of flexible structures.

Kirkham, Harold

1996-01-01

296

Electric power scheduling: A distributed problem-solving approach  

NASA Technical Reports Server (NTRS)

Space Station Freedom's power system, along with the spacecraft's other subsystems, needs to carefully conserve its resources and yet strive to maximize overall Station productivity. Due to Freedom's distributed design, each subsystem must work cooperatively within the Station community. There is a need for a scheduling tool which will preserve this distributed structure, allow each subsystem the latitude to satisfy its own constraints, and preserve individual value systems while maintaining Station-wide integrity. The value-driven free-market economic model is such a tool.

Mellor, Pamela A.; Dolce, James L.; Krupp, Joseph C.

1990-01-01

297

Probabilistic analysis of the distributed power generation in weakly meshed distribution systems  

Microsoft Academic Search

This paper presents an approach for probabilistic analysis of unbalanced three-phase weakly meshed distribution systems considering uncertainty in load demand. In order to achieve high computational efficiency this approach uses both an efficient method for probabilistic analysis and a radial power flow. The probabilistic approach used is the well-known Two-Point Estimate Method. Meanwhile, the compensation-based radial power flow is used

C. A. Peñuela; G. E. Mauricio; J. R. S. Mantovani

2010-01-01

298

Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration  

SciTech Connect

We show how distributed control of reactive power can serve to regulate voltage and minimize resistive losses in a distribution circuit that includes a significant level of photovoltaic (PV) generation. To demonstrate the technique, we consider a radial distribution circuit with a single branch consisting of sequentially-arranged residential-scale loads that consume both real and reactive power. In parallel, some loads also have PV generation capability. We postulate that the inverters associated with each PV system are also capable of limited reactive power generation or consumption, and we seek to find the optimal dispatch of each inverter's reactive power to both maintain the voltage within an acceptable range and minimize the resistive losses over the entire circuit. We assume the complex impedance of the distribution circuit links and the instantaneous load and PV generation at each load are known. We compare the results of the optimal dispatch with a suboptimal local scheme that does not require any communication. On our model distribution circuit, we illustrate the feasibility of high levels of PV penetration and a significant (20% or higher) reduction in losses.

Chertkov, Michael [Los Alamos National Laboratory; Turitsyn, Konstantin [Los Alamos National Laboratory; Backhaus, Scott [Los Alamos National Laboratory; Sule, Petr [NEW MEXICO CONSORTIUM

2009-01-01

299

Power system distributed oscilation detection based on Synchrophasor data  

NASA Astrophysics Data System (ADS)

Along with increasing demand for electricity, integration of renewable energy and deregulation of power market, power industry is facing unprecedented challenges nowadays. Within the last couple of decades, several serious blackouts have been taking place in United States. As an effective approach to prevent that, power system small signal stability monitoring has been drawing more interests and attentions from researchers. With wide-spread implementation of Synchrophasors around the world in the last decade, power systems real-time online monitoring becomes much more feasible. Comparing with planning study analysis, real-time online monitoring would benefit control room operators immediately and directly. Among all online monitoring methods, Oscillation Modal Analysis (OMA), a modal identification method based on routine measurement data where the input is unmeasured ambient excitation, is a great tool to evaluate and monitor power system small signal stability. Indeed, high sampling Synchrophasor data around power system is fitted perfectly as inputs to OMA. Existing methods in OMA for power systems are all based on centralized algorithms applying at control centers only; however, with rapid growing number of online Synchrophasors the computation burden at control centers is and will be continually exponentially expanded. The increasing computation time at control center compromises the real-time feature of online monitoring. The communication efforts between substation and control center will also be out of reach. Meanwhile, it is difficult or even impossible for centralized algorithms to detect some poorly damped local modes. In order to avert previous shortcomings of centralized OMA methods and embrace the new changes in the power systems, two new distributed oscillation detection methods with two new decentralized structures are presented in this dissertation. Since the new schemes brought substations into the big oscillation detection picture, the proposed methods could achieve faster and more reliable results. Subsequently, this claim is tested and approved by test results of IEEE Two-area simulation test system and real power system historian synchrophasor data case studies.

Ning, Jiawei

300

I-BIEM calculations of the frequency dispersion and AC current distribution at disk and ring-disk electrodes  

NASA Technical Reports Server (NTRS)

The Iterative Boundary Integral Equation Method (I-BIEM) has been applied to the problem of frequency dispersion at a disk electrode in a finite geometry. The I-BIEM permits the direct evaluation of the AC potential (a complex variable) using complex boundary conditions. The point spacing was made highly nonuniform, to give extremely high resolution in those regions where the variables change most rapidly, i.e., in the vicinity of the edge of the disk. Results are analyzed with respect to IR correction, equipotential surfaces, and reference electrode placement. The current distribution is also examined for a ring-disk configuration, with the ring and the disk at the same AC potential. It is shown that the apparent impedance of the disk is inductive at higher frequencies. The results are compared to analytic calculations from the literature, and usually agree to better than 0.001 percent.

Cahan, Boris D.

1991-01-01

301

I-BIEM calculations of the frequency dispersion and ac current distribution at disk and ring-disk electrodes  

NASA Technical Reports Server (NTRS)

The Iterative Boundary Integral Equation Method (I-BIEM) has been applied to the problem of frequency dispersion at a disk electrode in a finite geometry. The I-BIEM permits the direct evaluation of the AC potential (a complex variable) using complex boundary conditions. The point spacing was made highly nonuniform, to give extremely high resolution in those regions where the variables change most rapidly, i.e., in the vicinity of the edge of the disk. Results are analyzed with respect to IR correction, equipotential surfaces, and reference electrode placement. The current distribution is also examined for a ring-disk configuration, with the ring and the disk at the same AC potential. It is shown that the apparent impedance of the disk is inductive at higher frequencies. The results are compared to analytic calculations from the literature, and usually agree to better than 0.001 percent.

Cahan, Boris D.

1991-01-01

302

Reliability Improvement Programs in Steam Distribution and Power Generation Systems  

E-print Network

Steam Group of failed open traps affecting Trap the differential pressures. Insufficient Heat Low differential pressure affecting Transfer the steam trap flow rate. Freezing Bottlenecks in the condensate system. Water Hammer Trap discharge over ~OF...REI:IABILITY IMPROVEMENT PROGRAMS IN STEAM DISTRIBUTION AND POWER GENERATION SYSTEMS Robert D. Atlas Tech/Serv Corporation Blue Bell, PA This paper will present alternatives to costly corrective maintenance repairs of the steam trap...

Atlas, R. D.

303

London house prices are power-law distributed  

E-print Network

In this pilot study we explore the house price distributions for London, Manchester, Bristol, Newcastle, Birmingham and Leeds. We find Pareto (power law) behaviour in their upper tails, which is clearly distinct from lognormal behaviour in the cases of London and Manchester. We propose an index of Housing Wealth Inequality based on the Pareto exponent and analogous to the Gini coefficient, and comment on its possible uses.

MacKay, Niall

2010-01-01

304

Discussion on Modulation Methods for Flyback-type Single-Phase Inverters with Enhanced Power Decoupling for Photovoltaic AC Module Systems  

NASA Astrophysics Data System (ADS)

A photovoltaic AC module system has been expected to be installed on the private residences. The AC module inverter needs an active power decoupling circuit in order to enlarge the lifetimes of the inverter by eliminating a large electrolytic capacitor on the DC input bus. This paper proposes a novel modulation method, which we call Time-shared Magnetizing Modulation (TMM) method, realizing the power decoupling in the AC module flyback inverter as well as improving the efficiency conversion. The Sequential Magnetizing Modulation (SMM) method, which the authors have proposed earlier, are compared with the proposed method in operation principle and conversion efficiency point of view. It is verified that the TMM method has advantage with respect to the conversion efficiency. This paper concludes that the flyback inverter with the TMM method for the power decoupling is one of the suitable method for a single-phase grid interactive inverter used in the AC module system.

Hirao, Takashi; Shimizu, Toshihisa; Ishikawa, Mutsuo; Yasui, Kiyoto

305

Power-law velocity distributions in granular gases  

NASA Astrophysics Data System (ADS)

The kinetic theory of granular gases is studied for spatially homogeneous systems. At large velocities, the equation governing the velocity distribution becomes linear, and it admits stationary solutions with a power-law tail, f(v)˜v-? . This behavior holds in arbitrary dimension for arbitrary collision rates including both hard spheres and Maxwell molecules. Numerical simulations show that driven steady states with the same power-law tail can be realized by injecting energy into the system at very high energies. In one dimension, we also obtain self-similar time-dependent solutions where the velocities collapse to zero. At small velocities there is a steady state and a power-law tail but at large velocities, the behavior is time dependent with a stretched exponential decay.

Ben-Naim, E.; Machta, B.; Machta, J.

2005-08-01

306

The AC photovoltaic module concept  

SciTech Connect

The concept of the AC photovoltaic module--a photovoltaic module with an integral dc to ac inverter--was conceived 20 years ago at Caltech`s Jet Propulsion Laboratory, but is only now reaching commercial realization. Advances in power electronics, integrated circuits, microprocessors and communications were needed before AC photovoltaic modules could become a reality. Advanced Energy Systems and Solarex (the largest US-owned PV manufacturer) are now bringing the first commercial AC PV module to market. This is a 240 Watt peak large-area (6 feet, 3 inches x 3 feet, 8 inches) PV module with an integral 240 Watt inverter (4 Amps, 60 V dc input to 120V ac, 60 Hz, 2A output). The AC Module concept has many advantages over central inverter systems--the main ones being a low minimum system size (and hence a low barrier to market entry) and the ability to site individual modules without concern for shading and orientation. The authors believe that the AC PV module will become a significant consumer product and will have wide application as part of the emerging distributed electric utility.

Wills, R.H. [Advanced Energy Systems, Inc., Wilton, NH (United States); Krauthamer, S. [California Inst. of Tech., Pasadena, CA (United States). Jet Propulsion Lab.; Bulawka, A. [Dept. of Energy, Washington, DC (United States); Posbic, J.P. [Solarex, Frederick, MD (United States)

1997-12-31

307

Full Bridge-full Wave Mode Three-level AC\\/AC Converter with High Frequency Link  

Microsoft Academic Search

At present, the primary methods of realizing AC\\/AC voltage transformation are frequency transformer, AC-DC-AC converter, matrix converter, high-frequency link AC\\/AC converters and single-stage AC\\/AC converters. In areas of high power conversion, taking into account to converter's cost and the quality of output voltage, bridge mode AC\\/AC converter has some advantages. This converter can realize electrical isolation, high input power factor

Kaiming Yang; Lei Li

2009-01-01

308

A planning scheme for penetrating embedded generation in power distribution grids  

E-print Network

Penetrating Embedded Generation, or Distributed Generation (DG), in power distribution grids presents great benefits and substantial positive social impacts to utilities, system operators and electricity consumers. Existing ...

Wang, Jiankang, Ph. D. Massachusetts Institute of Technology

2013-01-01

309

Time series power flow analysis for distribution connected PV generation.  

SciTech Connect

Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating potential PV impacts.

Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J. [Georgia Institute of Technology, Atlanta, GA; Smith, Jeff [Electric Power Research Institute, Knoxville, TN; Dugan, Roger [Electric Power Research Institute, Knoxville, TN

2013-01-01

310

Intraluminal ultrasound intensity distribution and backscattered Doppler power.  

PubMed

Ultrasound (US) incident obliquely on a cylindrical vessel is redistributed in space when the propagation path includes walls with acoustic impedance different from that of the surrounding media. We investigated this using low-density polyethylene (PE) as the vessel wall material. Both simulations and experiments were carried out. Direct hydrophone measurements of the acoustic field were made within a half section of the PE tube, and the distribution of backscattered Doppler power along a scan line was obtained using a range-Doppler instrument. Both simulation and hydrophone results demonstrate lateral shadow regions within the lumen. In every one of various Doppler flow experiments conducted, the backscattered Doppler power, compensated for on-axis transducer behaviour, increased with depth. Simulation results for an incident continuous-wave (CW) plane wave show that it tends to be focused by the curvature of the PE tube walls. The wall interactions are, however, angle-dependent and so the behaviour of a focused US beam depends on the beam as well as the walls. This study demonstrates alterations in the spatial distribution of US within a cylindrical vessel as a result of known vessel wall properties. It also provides evidence that local intensity variations within the lumen affect the relative Doppler power backscattered from small sample volumes. PMID:15588959

Thompson, Rosemary S; Bambi, Giacomo; Steel, Robin; Tortoli, Piero

2004-11-01

311

Distribution of power output when establishing a breakaway in cycling.  

PubMed

A number of laboratory-based performance tests have been designed to mimic the dynamic and stochastic nature of road cycling. However, the distribution of power output and thus physical demands of high-intensity surges performed to establish a breakaway during actual competitive road cycling are unclear. Review of data from professional road-cycling events has indicated that numerous short-duration (5-15 s), high-intensity (~9.5-14 W/kg) surges are typically observed in the 5-10 min before athletes' establishing a breakaway (ie, riding away from a group of cyclists). After this initial high-intensity effort, power output declined but remained high (~450-500 W) for a further 30 s to 5 min, depending on race dynamics (ie, the response of the chase group). Due to the significant influence competitors have on pacing strategies, it is difficult for laboratory-based performance tests to precisely replicate this aspect of mass-start competitive road cycling. Further research examining the distribution of power output during competitive road racing is needed to refine laboratory-based simulated stochastic performance trials and better understand the factors important to the success of a breakaway. PMID:23539668

Abbiss, Chris R; Menaspà, Paolo; Villerius, Vincent; Martin, David T

2013-07-01

312

A Study on Collaborative Operation Method for a New Energy Type Dispersed Power Supply System by AC-EMAP Model  

NASA Astrophysics Data System (ADS)

Application of a dispersed power supply system combined with a large scale photovoltaic system (PV), a fuel cell (FC) and an electric double layer capacitor (EDLC) is studied in this paper. This system is operated in autonomous mode, taking account of time delay characteristics of FC. The modified Euler type Moving Average Prediction (EMAP) model is improved using short time fast fourier transform (ST-FFT). The Adaptive Control type EMAP (AC-EMAP) model is introduced to reduce the capacity of EDLC. This system can meet the multi-quality electric power requirements of customers, and compensate voltage stability and uninterruptible power supply (UPS) function as well. Moreover, the required capacity of EDLC to compensate the fluctuation of both PV output and load demand is clarified by the simulation based on collaborative operation method by a prediction model using software MATLAB/Simulink.

Hidese, Koichi; Takano, Ichiro; Nishikawa, Hisao; Sawada, Yoshio

313

Autonomous adaptive agents for distributed control of the electric power grid in a competitive electric power industry  

Microsoft Academic Search

A generic model of a complete electric power grid (including generation, transmission, distribution and loads), based on multiple adaptive, intelligent agents, is being developed by the Electric Power Research Institute (EPRT). Its ultimate purpose is to model the computational intelligence required for distributed control of a geographically dispersed but globally interconnected power network. The current worldwide trend toward free competition

A. Martin Wildberger

1997-01-01

314

A Multi-Agent Design for Power Distribution Systems Automation  

NASA Astrophysics Data System (ADS)

A new Multi Agent System (MAS) design for fault location, isolation and restoration in power distribution systems is presented. In proposed approach, when there is a fault in the Power Distribution System (PDS), MAS quickly isolates the fault and restores the service to fault-free zones. Hierarchical coordination strategy is introduced to manage the agents which integrate the advantages of both centralized and decentralized coordination strategies. In this framework, Zone Agent (ZA) locate and isolate the fault based on the locally available information and assist the Feeder Agent (FA) for reconfiguration and restoration. FA can solve the restoration problem using the existing algorithms for the 0-1 Knapsack problem. A novel Q-learning mechanism is also introduced to support the FAs in decision making for restoration. Also a distributed MAS-Based Load Shedding (LS) technique has been used to supply as many of higher priority customers as possible, in case there is more demand than generation. The design is illustrated by the use of simulation case studies for fault location, isolation and restoration on West Virginia Super Circuit (WVSC) and hardware implementation for fault location and isolation in a laboratory platform. The results from the case studies indicate the performance of proposed MAS designs.

Ghorbani, M. Jawad

315

A majorization-minimization approach to design of power distribution networks  

SciTech Connect

We consider optimization approaches to design cost-effective electrical networks for power distribution. This involves a trade-off between minimizing the power loss due to resistive heating of the lines and minimizing the construction cost (modeled by a linear cost in the number of lines plus a linear cost on the conductance of each line). We begin with a convex optimization method based on the paper 'Minimizing Effective Resistance of a Graph' [Ghosh, Boyd & Saberi]. However, this does not address the Alternating Current (AC) realm and the combinatorial aspect of adding/removing lines of the network. Hence, we consider a non-convex continuation method that imposes a concave cost of the conductance of each line thereby favoring sparser solutions. By varying a parameter of this penalty we extrapolate from the convex problem (with non-sparse solutions) to the combinatorial problem (with sparse solutions). This is used as a heuristic to find good solutions (local minima) of the non-convex problem. To perform the necessary non-convex optimization steps, we use the majorization-minimization algorithm that performs a sequence of convex optimizations obtained by iteratively linearizing the concave part of the objective. A number of examples are presented which suggest that the overall method is a good heuristic for network design. We also consider how to obtain sparse networks that are still robust against failures of lines and/or generators.

Johnson, Jason K [Los Alamos National Laboratory; Chertkov, Michael [Los Alamos National Laboratory

2010-01-01

316

Modeling and characterization of an aircraft electric power system with a fuel cell-equipped APU paralleled at main AC bus  

Microsoft Academic Search

In this paper a More Electric Aircraft (MEA) electric power system is modeled and simulated with a fuel cell\\/battery hybrid Auxiliary Power Unit (APU). Fuel cell\\/battery hybrid power source is connected at the AC-load bus bar of 200-VAC and 400-Hz. Due to the DC output of the hybrid power source, a 12-pulse inverter is used at the output of the

A. Eid; H. El-Kishky; M. Abdel-Salam; T. El-Mohandes

2010-01-01

317

Measurement of the temperature distribution inside the power cable using distributed temperature system  

NASA Astrophysics Data System (ADS)

Nowadays, the power cables are manufactured to fulfill the following condition - the highest allowable temperature of the cable during normal operation and the maximum allowable temperature at short circuit conditions cannot exceed the condition of the maximum allowable internal temperature. The distribution of the electric current through the conductor leads to the increase of the amplitude of electrons in the crystal lattice of the cables material. The consequence of this phenomenon is the increase of friction and the increase of collisions between particles inside the material, which causes the temperature increase of the carrying elements. The temperature increase is unwanted phenomena, because it is causing losses. In extreme cases, the long-term overload leads to the cable damaging or fire. This paper deals with the temperature distribution measurement inside the power cables using distributed temperature system. With cooperation with Kabex company, the tube containing optical fibers was installed into the center of power cables. These fibers, except telecommunications purposes, can be also used as sensors in measurements carrying out with distributed temperature system. These systems use the optical fiber as a sensor and allow the continual measurement of the temperature along the whole cable in real time with spatial resolution 1 m. DTS systems are successfully deployed in temperature measurement applications in industry areas yet. These areas include construction, drainage, hot water etc. Their advantages are low cost, resistance to electromagnetic radiation and the possibility of real time monitoring at the distance of 8 km. The location of the optical fiber in the center of the power cable allows the measurement of internal distribution of the temperature during overloading the cable. This measurement method can be also used for prediction of short-circuit and its exact location.

Jaros, Jakub; Liner, Andrej; Papes, Martin; Vasinek, Vladimir; Mach, Veleslav; Hruby, David; Kajnar, Tomas; Perecar, Frantisek

2015-01-01

318

Tomographic determination of the power distribution in electron beams  

DOEpatents

A tomographic technique for determining the power distribution of an electron beam using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams is disclosed. A refractory metal disk with a number of radially extending slits is placed above a Faraday cup. The beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. Also, a single computer is used to generate the signals actuating the sweep, to acquire that data, and to do the reconstruction, thus reducing the time and equipment necessary to complete the process. 4 figs.

Teruya, A.T.; Elmer, J.W.

1996-12-10

319

Probability distributions and confidence intervals for simulated power law noise.  

PubMed

A method for simulating power law noise in clocks and oscillators is presented based on modification of the spectrum of white phase noise, then Fourier transforming to the time domain. Symmetric real matrices are introduced whose traces-the sums of their eigenvalues-are equal to the Allan variances, in overlapping or non-overlapping forms, as well as for the corresponding forms of the modified Allan variance. We show that the standard expressions for spectral densities, and their relations to Allan variance, are obtained with this method. The matrix eigenvalues determine probability distributions for observing a variance at an arbitrary value of the sampling interval ?, and hence for estimating confidence in the measurements. Examples are presented for the common power-law noises. Extension to other variances such as the Hadamard variance, and variances with dead time, are discussed. PMID:25585396

Ashby, Neil

2015-01-01

320

Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation  

SciTech Connect

This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the July 2003 to December 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

Faress Rahman; Nguyen Minh

2004-01-04

321

Tomographic determination of the power distribution in electron beams  

DOEpatents

A tomographic technique for determining the power distribution of an electron beam using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. A refractory metal disk with a number of radially extending slits is placed above a Faraday cup. The beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. Also, a single computer is used to generate the signals actuating the sweep, to acquire that data, and to do the reconstruction, thus reducing the time and equipment necessary to complete the process.

Teruya, Alan T. (Livermore, CA); Elmer, John W. (Pleasanton, CA)

1996-01-01

322

Automated fault location and diagnosis on electric power distribution feeders  

SciTech Connect

This paper presents new techniques for locating and diagnosing faults on electric power distribution feeders. The proposed fault location and diagnosis scheme is capable of accurately identifying the location of a fault upon its occurrence, based on the integration of information available from disturbance recording devices with knowledge contained in a distribution feeder database. The developed fault location and diagnosis system can also be applied to the investigation of temporary faults that may not result in a blown fuse. The proposed fault location algorithm is based on the steady-state analysis of the faulted distribution network. To deal with the uncertainties inherent in the system modeling and the phasor estimation, the fault location algorithm has been adapted to estimate fault regions based on probabilistic modeling and analysis. Since the distribution feeder is a radial network, multiple possibilities of fault locations could be computed with measurements available only at the substation. To identify the actual fault location, a fault diagnosis algorithm has been developed to prune down and rank the possible fault locations by integrating the available pieces of evidence. Testing of the developed fault location and diagnosis system using field data has demonstrated its potential for practical use.

Zhu, J. [Advanced Control Systems, Inc., Norcross, GA (United States); Lubkeman, D.L.; Girgis, A.A. [Clemson Univ., SC (United States). Dept. of Electrical and Computer Engineering

1997-04-01

323

Single-phase power distribution system power flow and fault analysis  

NASA Technical Reports Server (NTRS)

Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques.

Halpin, S. M.; Grigsby, L. L.

1992-01-01

324

A new concept of electrical power supply for AC arc furnaces  

Microsoft Academic Search

Electrical arc furnaces (EAFs) cause many power quality problems on the power network. Static var compensator or STATCOM are typically used for power quality requirements. In this paper the authors evaluate different STATCOM control strategy on the power system for two points of view: power quality requirements and furnace productivity enhancement. Simulation results, based on a new arc furnace electrical

G. Postiglione; P. Ladoux

2006-01-01

325

Subsystem Interaction Analysis in Power Distribution Systems of Next Generation Airlifters  

E-print Network

1 Subsystem Interaction Analysis in Power Distribution Systems of Next Generation Airlifters Sriram power distribution system of a next generation transport aircraft is addressed. Detailed analysis with the analysis of subsystem integration in power distribution systems of next generation transport aircraft

Lindner, Douglas K.

326

Automated di/dt Stressmark Generation for Microprocessor Power Distribution Networks  

E-print Network

Automated di/dt Stressmark Generation for Microprocessor Power Distribution Networks Youngtaek Kim for automated di/dt stressmark generation to test maximum voltage droop in a microprocessor power distribution and typical benchmarks in experiments covering three micro-processor architectures and five power distribution

John, Lizy Kurian

327

Study of the longitudinal distribution of power generated in a random distributed feedback Raman fibre laser with unidirectional pumping  

SciTech Connect

The longitudinal distribution of the Stokes-component power in a Raman fibre laser with a random distributed feedback and unidirectional pumping is measured. The fibre parameters (linear loss and Rayleigh backscattering coefficient) are calculated based on the distributions obtained. A numerical model is developed to describe the lasing power distribution. The simulation results are in good agreement with the experimental data. (optical fibres, lasers and amplifiers. properties and applications)

Churkin, D V; El-Taher, A E; Vatnik, I D; Babin, Sergei A

2012-09-30

328

Abstract--Distributed generation (DG) has brought great attention from the power community, especially  

E-print Network

1 Abstract-- Distributed generation (DG) has brought great attention from the power community, such distributed generation (DG). DG applications in the vicinity of the load show great operational and power, it produces changes on the power flow pattern. The natural and renewable power generation coming from wind

Catholic University of Chile (Universidad Católica de Chile)

329

Power Distribution Paths in 3-D ICs Vasilis F. Pavlidis Giovanni De Micheli  

E-print Network

to a vertically integrated system is a complex and difficult task. Interplane communication and power delivery power distribution networks have been developed with power grids being a commonly used topology [2Power Distribution Paths in 3-D ICs Vasilis F. Pavlidis Giovanni De Micheli LSI-EPFL 1015-Lausanne

De Micheli, Giovanni

330

DC/AC Circuits Student Guide: Agilent U3000 Power Supply Lab Activity Part 1  

NSDL National Science Digital Library

This lab activity introduces you to the basic theory and operation of a lab power supply. The lab is focused on using the power supply as a tool to power electronic systems. Power supply theory, terminology, and operation are stressed. Since all systems require a power supply, a technician needs to understand the basic theory of operation, the common terminology used with all power supplies, and, ultimately, their efficient use. Technicians setup, use, and test power supplies in virtually all job classifications. Therefore, power supply functionally becomes a required skill of the job.

Brixen, Roy

2014-08-04

331

Fuel cycle comparison of distributed power generation technologies.  

SciTech Connect

The fuel-cycle energy use and greenhouse gas (GHG) emissions associated with the application of fuel cells to distributed power generation were evaluated and compared with the combustion technologies of microturbines and internal combustion engines, as well as the various technologies associated with grid-electricity generation in the United States and California. The results were primarily impacted by the net electrical efficiency of the power generation technologies and the type of employed fuels. The energy use and GHG emissions associated with the electric power generation represented the majority of the total energy use of the fuel cycle and emissions for all generation pathways. Fuel cell technologies exhibited lower GHG emissions than those associated with the U.S. grid electricity and other combustion technologies. The higher-efficiency fuel cells, such as the solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC), exhibited lower energy requirements than those for combustion generators. The dependence of all natural-gas-based technologies on petroleum oil was lower than that of internal combustion engines using petroleum fuels. Most fuel cell technologies approaching or exceeding the DOE target efficiency of 40% offered significant reduction in energy use and GHG emissions.

Elgowainy, A.; Wang, M. Q.; Energy Systems

2008-12-08

332

The investigation of an electric arc in the long cylindrical channel of the powerful high-voltage AC plasma torch  

NASA Astrophysics Data System (ADS)

The comparison of conductivity obtained in experiments with calculated values is made in this paper. Powerful stationary plasma torches with prolonged period of continuous work are popular for modern plasmachemical applications. The maximum electrode lifetime with the minimum erosion can be reached while working on rather low currents. Meanwhile it is required to provide voltage arc drop for the high power achievement. Electric field strength in the arc column of the high-voltage plasma torch, using air as a plasma-forming gas, does not exceed 15 V/cm. It is possible to obtain the high voltage drop in the long arc stabilized in the channel by the intensive gas flow under given conditions. Models of high voltage plasma torches with rod electrodes with power up to 50 kW have been developed and investigated. The plasma torch arcs are burning in cylindrical channels. Present investigations are directed at studying the possibility of developing long arc plasma torches with higher power. The advantage of AC power supplies usage is the possibility of the loss minimization due to the reactive power compensation. The theoretical maximum of voltage arc drop for power supplies with inductive current limitations is about 50 % of the no-load voltage for a single-phase circuit and about 30 % for the three-phase circuit. Burning of intensively blown arcs in the long cylindrical channel using the AC power supply with 10 kV no-load voltage is experimentally investigated in the work. Voltage drops close to the maximum possible had been reached in the examined arcs in single-phase and three-phase modes. Operating parameters for single-phase mode were: current -30 A, voltage drop -5 kV, air flow rate 35 g/s; for three-phase mode: current (40-85) A, voltage drop (2.5-3.2) kV, air flow rate (60-100) g/s. Arc length in the installations exceeded 2 m.

Rutberg, Ph G.; Popov, S. D.; Surov, A. V.; Serba, E. O.; Nakonechny, Gh V.; Spodobin, V. A.; Pavlov, A. V.; Surov, A. V.

2012-12-01

333

AC loss properties of a 1 MVA single-phase HTS power transformer  

Microsoft Academic Search

We designed and built a single-phase 1 MVA-22\\/6.9 kV HTS transformer with the multi-layered cylindrical windings composed of Bi2223 parallel conductors. In advance of the design, the AC loss induced in the windings was estimated on the basis of the observed results in a strand. A subcooled liquid nitrogen cryogenic system with the corresponding cooling capacity was developed and attached

M. Iwakuma; K. Funaki; K. Kajikawa; H. Tanaka; T. Bohno; A. Tomioka; H. Yamada; S. Nose; M. Konno; Y. Yagi; H. Maruyama; T. Ogata; S. Yoshida; K. Ohashi; K. Tsutsumi; K. Honda

2001-01-01

334

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

SciTech Connect

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.

None

2010-09-01

335

Development of a low cost integrated 15 kW AC solar tracking subarray for grid connected PV power system applications  

Microsoft Academic Search

The Utility Power Group has reduced the installation cost of grid connected photovoltaic power systems through a two step approach of integrating and packaging all sub-array power conversion and control functions within a single factory produced enclosure and utilizing large area factory assembled photovoltaic panels. A modular 15 kW AC single axis solar tracking sub-array was designed to meet the

M. J. Stern; R. T. West

1996-01-01

336

SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION  

SciTech Connect

This report summarizes the work performed by Honeywell during the October 2001 to December 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The conceptual and demonstration system designs were proposed and analyzed, and these systems have been modeled in Aspen Plus. Work has also started on the assembly of dynamic component models and the development of the top-level controls requirements for the system. SOFC stacks have been fabricated and performance mapping initiated.

Kurt Montgomery; Nguyen Minh

2003-08-01

337

Molecular clouds have power-law probability distribution functions  

E-print Network

In this Letter we investigate the shape of the probability distribution of column densities (PDF) in molecular clouds. Through the use of low-noise, extinction-calibrated \\textit{Herschel}/\\textit{Planck} emission data for eight molecular clouds, we demonstrate that, contrary to common belief, the PDFs of molecular clouds are not described well by log-normal functions, but are instead power laws with exponents close to two and with breaks between $A_K \\simeq 0.1$ and $0.2\\,\\mathrm{mag}$, so close to the CO self-shielding limit and not far from the transition between molecular and atomic gas. Additionally, we argue that the intrinsic functional form of the PDF cannot be securely determined below $A_K \\simeq 0.1\\,\\mathrm{mag}$, limiting our ability to investigate more complex models for the shape of the cloud PDF.

Lombardi, Marco; Lada, Charles J

2015-01-01

338

SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION  

SciTech Connect

This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the January 2003 to June 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. This report summarizes the results obtained to date on: System performance analysis and model optimization; Reliability and cost model development; System control including dynamic model development; Heat exchanger material tests and life analysis; Pressurized SOFC evaluation; and Pre-baseline system definition for coal gasification fuel cell system concept.

Faress Rahman; Nguyen Minh

2003-07-01

339

Soft-Switching High-Frequency AC-Link Universal Power Converters with Galvanic Isolation  

E-print Network

be used in a variety of applications, including photovoltaic power generation, wind power generation, and electric vehicles. In these converters the link current and voltage are both alternating and their frequency can be high, which leads...

Amirabadi, Mahshid

2013-08-07

340

Aging Management Guideline for commercial nuclear power plants: Power and distribution transformers  

SciTech Connect

This Aging Management Guideline (AMG) provides recommended methods for effective detection and mitigation of age-related degradation mechanisms in power and distribution transformers important to license renewal in commercial nuclear power plants. The intent of this AMG to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner which allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

Toman, G.; Gazdzinski, R. [Sandia National Labs., Albuquerque, NM (United States)

1994-05-01

341

Simultaneous Co-Design of Distributed On-Chip Power Supplies and Decoupling Capacitors  

E-print Network

Simultaneous Co-Design of Distributed On-Chip Power Supplies and Decoupling Capacitors Selc¸uk K-chip power supplies and intentional decoupling capacitors inserted throughout an integrated circuit further and decoupling capacitors, a new design methodology is required to simultaneously design the power distribution

Friedman, Eby G.

342

Validating MCNP for LEU Fuel Design via Power Distribution Comparisons  

SciTech Connect

The mission of the Reduced Enrichment for Research and Test Reactors (RERTR) Program is to minimize and, to the extent possible, eliminate the use of highly enriched uranium (HEU) in civilian nuclear applications by working to convert research and test reactors, as well as radioisotope production processes, to low enriched uranium (LEU) fuel and targets. Oak Ridge National Lab (ORNL) is reviewing the design bases and key operating criteria including fuel operating parameters, enrichment-related safety analyses, fuel performance, and fuel fabrication in regard to converting the fuel of the High Flux Isotope Reactor (HFIR) from HEU to LEU. The purpose of this study is to validate Monte Carlo methods currently in use for conversion analyses. The methods have been validated for the prediction of flux values in the reactor target, reflector, and beam tubes, but this study focuses on the prediction of the power density profile in the core. A current 3-D Monte Carlo N-Particle (MCNP) model was modified to replicate the HFIR Critical Experiment 3 (HFIRCE-3) core of 1965. In this experiment, the power profile was determined by counting the gamma activity at selected locations in the core. Foils (chunks of fuel meat and clad) were punched out of the fuel elements in HFIRCE-3 following irradiation and experimental relative power densities were obtained by measuring the activity of these foils and comparing each foil s activity to the activity of a normalizing foil. The current work consisted of calculating corresponding activities by inserting volume tallies into the modified MCNP model to represent the punchings. The average fission density was calculated for each foil location and then normalized to the normalizing foil. Power distributions were obtained for the clean core (no poison in moderator and symmetrical rod position at 17.5 inches) and fully poisoned-moderator (1.35 g B/liter in moderator and rods fully withdrawn) conditions. The observed deviations between the experimental and calculated values for both conditions were within the reported experimental uncertainties except for some of the foils located on the top and bottom edges of the fuel plates.

Primm, Trent [ORNL; Maldonado, G Ivan [ORNL; Chandler, David [ORNL

2008-11-01

343

ELSEVIER Physica A 242 (1997) 90-94 New evidence for the power-law distribution  

E-print Network

PHYSiCA ELSEVIER Physica A 242 (1997) 90-94 New evidence for the power-law distribution of wealth the distribution of wealth in society. We analyze data from the 1996 Forbes 400 list of the richest people in the US. Our results confirm that wealth is distributed according to a power law. The measured exponent

344

Fast Numerical Computation of Current Distribution and AC Losses in Helically Wound Thin Tape Conductors: Single-Layer Coaxial Arrangement  

Microsoft Academic Search

In this paper, we introduce a very fast method to compute the current distribution in helically wound thin conductors when one or many of them are arranged in a symmetrical manner to form a single-layer power cable. The method relies on two different approaches to find the magnetic vector potential due to helically wound current sheets. By invoking relevant symmetry

Majid Siahrang; Frédéric Sirois; Doan N. Nguyen; Slobodan Babic; Stephen P. Ashworth

2010-01-01

345

Flyback-Type Single-Phase Utility Interactive Inverter With Power Pulsation Decoupling on the DC Input for an AC Photovoltaic Module System  

Microsoft Academic Search

In recent years, interest in natural energy has grown in response to increased concern for the environment. Many kinds of inverter circuits and their control schemes for photovoltaic (PV) power generation systems have been studied. A conventional system employs a PV array in which many PV modules are connected in series to obtain sufficient dc input voltage for generating ac

Toshihisa Shimizu; Keiji Wada; Naoki Nakamura

2006-01-01

346

A Service Oriented Architecture for Exploring High Performance Distributed Power Models  

SciTech Connect

Power grids are increasingly incorporating high quality, high throughput sensor devices inside power distribution networks. These devices are driving an unprecedented increase in the volume and rate of available information. The real-time requirements for handling this data are beyond the capacity of conventional power models running in central utilities. Hence, we are exploring distributed power models deployed at the regional scale. The connection of these models for a larger geographic region is supported by a distributed system architecture. This architecture is built in a service oriented style, whereby distributed power models running on high performance clusters are exposed as services. Each service is semantically annotated and therefore can be discovered through a service catalog and composed into workflows. The overall architecture has been implemented as an integrated workflow environment useful for power researchers to explore newly developed distributed power models.

Liu, Yan; Chase, Jared M.; Gorton, Ian

2012-11-12

347

Inference of Statistical Patterns in Complex Geosystems: Fitting Power-law Distributions.  

NASA Astrophysics Data System (ADS)

Power-law distributions contain precious information about a large variety of physical processes. Although there are sound theoretical grounds for these distributions, the empirical evidence giving support to power laws has been traditionally weak. Recently, Clauset et al. have proposed a systematic method to find over which range (if any) a certain distribution behaves as a power law. However, their method fails to recognize true (simulated) power-law tails in some instances, rejecting the power-law hypothesis. Moreover, the method does not perform well when it is extended to power-law distributions with an upper truncation. We present an alternative procedure, valid for truncated as well as for non-truncated power-law distributions, based in maximum likelihood estimation, the Kolmogorov-Smirnov goodness-of-fit test, and Monte Carlo simulations. We will test the performance of our method on several empirical data which were previously analyzed with less systematic approaches.

Deluca, Anna; Corral, Alvaro

2014-05-01

348

Transport ac loss in a rectangular thin strip with power-law E (J) relation  

NASA Astrophysics Data System (ADS)

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.

Li, Shuo; Chen, Du-Xing; Fan, Yu; Fang, Jin

2015-01-01

349

Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation  

SciTech Connect

This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) under Cooperative Agreement DE-FC2601NT40779 for the US Department of Energy, National Energy Technology Laboratory (DoE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a gas turbine. A conceptual hybrid system design was selected for analysis and evaluation. The selected system is estimated to have over 65% system efficiency, a first cost of approximately $650/kW, and a cost of electricity of 8.4 cents/kW-hr. A control strategy and conceptual control design have been developed for the system. A number of SOFC module tests have been completed to evaluate the pressure impact to performance stability. The results show that the operating pressure accelerates the performance degradation. Several experiments were conducted to explore the effects of pressure on carbon formation. Experimental observations on a functioning cell have verified that carbon deposition does not occur in the cell at steam-to-carbon ratios lower than the steady-state design point for hybrid systems. Heat exchanger design, fabrication and performance testing as well as oxidation testing to support heat exchanger life analysis were also conducted. Performance tests of the prototype heat exchanger yielded heat transfer and pressure drop characteristics consistent with the heat exchanger specification. Multicell stacks have been tested and performance maps were obtained under hybrid operating conditions. Successful and repeatable fabrication of large (>12-inch diameter) planar SOFC cells was demonstrated using the tape calendering process. A number of large area cells and stacks were successfully performance tested at ambient and pressurized conditions. A 25 MW plant configuration was selected with projected system efficiency of over 65% and a factory cost of under $400/kW. The plant design is modular and can be scaled to both higher and lower plant power ratings. Integrated gasification fuel cell systems or IGFCs were developed and analyzed for plant sizes in excess of 200 MW. Two alternative integration configurations were selected with projected system efficiency of over 53% on a HHV basis, or about 10 percentage points higher than that of the state-of-the-art Integrated Gasification Combined Cycle (IGCC) systems.

Nguyen Minh

2005-12-01

350

A comparative study of AC\\/DC converters for high-power DC arc furnace  

Microsoft Academic Search

Today, dc arc furnaces are supplied by thyristor rectifiers. Because of the phase control strategy on the rectifiers, the arc voltage swings induce large reactive power variations on the power network and a static VAr compensator (SVC) or a static synchronous compensator (STATCOM) is always added to avoid flicker effect. In this paper, the authors present a new control strategy

Philippe Ladoux; Gianluca Postiglione; Henri Foch; Jacques Nuns

2005-01-01

351

Development of a low-cost integrated 20-kW-AC solar tracking subarray for grid-connected PV power system applications. Final technical report  

Microsoft Academic Search

This report chronicles Utility Power Group's (UPG) successful two-year Photovoltaic Manufacturing Technology (PVMaT) Phase 4A1 work effort which began in July, 1995. During this period, UPG completed design, fabrication, testing and demonstration of a modular and fully integrated 15-kW-ac, solar tracking PV power system sub-array. The two key and innovative components which were developed are a Modular Panel which optimizes

M. Stern; G. Duran; G. Fourer; K. Mackamul; W. Whalen; M. van Loo

1998-01-01

352

Development of a low cost integrated 15 kW A.C. solar tracking sub-array for grid connected PV power system applications  

Microsoft Academic Search

Utility Power Group has achieved a significant reduction in the installed cost of grid-connected PV systems. The two part technical approach focused on 1) The utilization of a large area factory assembled PV panel, and 2) The integration and packaging of all sub-array power conversion and control functions within a single factory produced enclosure. Eight engineering prototype 15kW ac single

M. Stern; G. Fourer; W. Whalen; M. van Loo; G. Duran

1997-01-01

353

The place of solar power: an economic analysis of concentrated and distributed solar power  

PubMed Central

Background This paper examines the cost and benefits, both financial and environmental, of two leading forms of solar power generation, grid-tied photovoltaic cells and Dish Stirling Systems, using conventional carbon-based fuel as a benchmark. Methods First we define how these solar technologies will be implemented and why. Then we delineate a model city and its characteristics, which will be used to test the two methods of solar-powered electric distribution. Then we set the constraining assumptions for each technology, which serve as parameters for our calculations. Finally, we calculate the present value of the total cost of conventional energy needed to power our model city and use this as a benchmark when analyzing both solar models’ benefits and costs. Results The preeminent form of distributed electricity generation, grid-tied photovoltaic cells under net-metering, allow individual homeowners a degree of electric self-sufficiency while often turning a profit. However, substantial subsidies are required to make the investment sensible. Meanwhile, large dish Stirling engine installations have a significantly higher potential rate of return, but face a number of pragmatic limitations. Conclusions This paper concludes that both technologies are a sensible investment for consumers, but given that the dish Stirling consumer receives 6.37 dollars per watt while the home photovoltaic system consumer receives between 0.9 and 1.70 dollars per watt, the former appears to be a superior option. Despite the large investment, this paper deduces that it is far more feasible to get few strong investors to develop a solar farm of this magnitude, than to get 150,000 households to install photovoltaic arrays in their roofs. Potential implications of the solar farm construction include an environmental impact given the size of land require for this endeavour. However, the positive aspects, which include a large CO2 emission reduction aggregated over the lifespan of the farm, outweigh any minor concerns or potential externalities. PMID:22540991

2012-01-01

354

MODELING OF A DSTATCOM WITH ULTRA-CAPACITOR ENERGY STORAGE FOR POWER DISTRIBUTION SYSTEM APPLICATIONS  

Microsoft Academic Search

Summary - This paper describes the dynamic modeling of a distribution static synchronous compensator (DSTATCOM) coupled with ultra-capacitor energy storage (UCES) for improving the power quality of power distribution systems. Two modes of operation are assessed, i.e. voltage control for voltage fluctuations ride-through and dynamic active power control for power flow compensation. New detailed models and dynamic control schemes are

M. G. MOLINA; Puerto Iguazú Argentina

355

Advanced Power Electronics Interfaces for Distributed Energy Workshop Summary: August 24, 2006, Sacramento, California  

SciTech Connect

The Advanced Power Electronics Interfaces for Distributed Energy Workshop, sponsored by the California Energy Commission Public Interest Energy Research program and organized by the National Renewable Energy Laboratory, was held Aug. 24, 2006, in Sacramento, Calif. The workshop provided a forum for industry stakeholders to share their knowledge and experience about technologies, manufacturing approaches, markets, and issues in power electronics for a range of distributed energy resources. It focused on the development of advanced power electronic interfaces for distributed energy applications and included discussions of modular power electronics, component manufacturing, and power electronic applications.

Treanton, B.; Palomo, J.; Kroposki, B.; Thomas, H.

2006-10-01

356

Distributed Bspline Electrothermal Models of SCR Devices for Power Applications and Bulk CMOS Latch-Up Characterizations.  

NASA Astrophysics Data System (ADS)

In this work, a distributed BSpline electrothermal model of a thyristor is developed to realistically count for the electrothermal spreading effect and the interaction between the electrical and thermal responses in a compiler -based and SPICE-like circuit simulator, MISIM. A comprehensive and systematic methodology is introduced to provide a guideline for realizing the BSpline electrothermal model of a thyristor from either simulated or experimental electrothermal characteristics. The topology of the temperature-dependent electrical model for a general thyristor is developed from the physical three-junction representation and the Ebers-Moll BJT model. To model the transient thermal behavior, the topology of the thermal model is represented by connecting a heat source, a thermal resistor, and a thermal capacitor in parallel. For obtaining the numerical representation of the characteristics associated with each element in both the electrical and thermal topologies, we employ a fitting technique based on the analytical, one-dimensional BSpline, and Tensor Product Spline numerical methods. The main purpose for using the BSpline fitting technique is to ensure the continuity of the first order derivative of the numerical representation. This continuity of the first order derivative prevents any potential non-convergence problem during the MISIM simulation. The detailed fitting processes for the characteristics associated with the DC, AC, and thermal models are described. The experimental used to obtain the parameters in the analytical equations for the DC, AC, and thermal models are presented. To implement the thermal model in MISIM, the elements in the thermal topology is transferred to a electrical analogue. The realization of our electrothermal model is achieved by simply merging the electrical and thermal models together. However, the electrothermal interaction is established by exchanging the instantaneous power and temperature information between the electrical and thermal models. Because our BSpline electrothermal model is scalable, a large area thyristor is represented by several scaled electrothermal models arranging in a two-dimensional distributed manner. The representation of a large area thyristor with the two-dimensional distributed electrothermal model is described in detail. With the MISIM input deck based on two-dimensional distributed electrothermal model, the inherent electrothermal spreading effect during the turn-on process of a large area thyristor is simulated by MISIM. The excellent agreements between the MISIM and PISCES simulated DC, AC, and electrothermal characteristics are shown.

Hung, Chih-Ju.

357

Future electronic power distribution systems a contemplative view  

Microsoft Academic Search

Although it has long been argued that electronic power converters can help improve system controllability, reliability, size, and efficiency, their penetration in power systems is still quite low. The often-cited barriers of higher cost and lower reliability of the power converters are quite high if power electronics is used as direct, one-to-one, replacement for the existing electromechanical equipment. However, if

Dushan Boroyevich; I. Cvetkovic; Dong Dong; R. Burgos; Fei Wang; F. Lee

2010-01-01

358

Improving Power Quality in Low-Voltage Networks Containing Distributed Energy Resources  

NASA Astrophysics Data System (ADS)

Severe power quality problems can arise when a large number of single-phase distributed energy resources (DERs) are connected to a low-voltage power distribution system. Due to the random location and size of DERs, it may so happen that a particular phase generates excess power than its load demand. In such an event, the excess power will be fed back to the distribution substation and will eventually find its way to the transmission network, causing undesirable voltage-current unbalance. As a solution to this problem, the article proposes the use of a distribution static compensator (DSTATCOM), which regulates voltage at the point of common coupling (PCC), thereby ensuring balanced current flow from and to the distribution substation. Additionally, this device can also support the distribution network in the absence of the utility connection, making the distribution system work as a microgrid. The proposals are validated through extensive digital computer simulation studies using PSCADTM.

Mazumder, Sumit; Ghosh, Arindam; Zare, Firuz

2013-05-01

359

Analysis and Steady-State Behavior of an Optimized AC Converter Machine  

Microsoft Academic Search

AC machines presently designed to operate from a solid state power converter retain a sinusoidal winding distribution even though such machines were originally intended only for operation with sinusoidal rather than rectangular power supplies. This paper describes a unique type of concentrated winding machine in which the winding distribution is intentionally rectangular to better accomodate the rectangular waveforms of conventional

F. X. Wang; T.A. Lipo

1983-01-01

360

AC loss of a model 5m 2G HTS power cable using wires with NiW substrates  

NASA Astrophysics Data System (ADS)

A model 5 m cable prototype was constructed using American Superconductor second generation (2G) high temperature superconductor (HTS) wires - 344 superconductors, produced with the MOD/RABiTSTM process. The model cable consists of two helically counterwound layers of brass-laminated tapes. Twist pitches were calculated to provide uniform current distribution between the two cable layers. The NiW substrates of the tapes were oriented to face radially inward and radially outward for the inner and outer layers of the cable, respectively, to minimize the spacing between the HTS layers and any effects of the weak substrate magnetism. To verify the calculations and design principles, the model cable was instrumented with potential taps and sensors, including Rogowski coils and Hall probes, to measure the current distribution among layers, voltage - current characteristics and other parameters. AC losses in this cable model have been measured and analyzed by use of digital measurements of current and voltage. At low to intermediate currents, they are in the range of a few tenths of a watt per meter, consistent with the ferromagnetic loss of the substrate. Analysis of the individual contributions of the Ni-W substrate and the superconductor hysteresis loss is given.

Vysotsky, V. S.; Shutov, K. A.; Nosov, A. A.; Polyakova, N. V.; Fetisov, S. S.; Zubko, V. V.; Sytnikov, V. E.; Carter, W. L.; Fleshler, S.; Malozemoff, A. P.; Snitchler, G.

2010-06-01

361

Power distribution in complex environmental negotiations: Does balance matter?  

USGS Publications Warehouse

We studied six interagency negotiations covering Federal Energy Regulatory Commission (FERC) hydroelectric power licenses. Negotiations occurred between state and federal resource agencies and developers over project operations and natural resource mitigation. We postulated that a balance of power among parties was necessary for successful negotiations. We found a complex relationship between balanced power and success and conclude that a balance of power was associated with success in these negotiations. Power played a dynamic role in the bargaining and illuminates important considerations for regulatory design.

Burkardt, N.; Lamb, B.L.; Taylor, J.G.

1997-01-01

362

Reliability and availability data collection program for power distribution, power generation, and HVAC components of commercial, industrial, and utility installations  

Microsoft Academic Search

This work presents an effort to collect operational and maintenance data on 240 power generation, power distribution and heating, ventilation, and air conditioning (HVAC) items, including gas turbine generators, diesel engine generators, electrical switchgear, cables, circuit breakers, boilers, piping, valves, pumps, motors and chillers. The data collection process and the resultant data are the subject of this paper.

P. S. Hale; R. G. Arno; D. D. Dylis

2004-01-01

363

Reliability and availability data collection program for power distribution, power generation, and HVAC components of commercial industrial, and utility installations  

Microsoft Academic Search

This paper presents an effort to collect operational and maintenance data on 240 power generation, power distribution and heating, ventilation, and air conditioning (HVAC) items, including gas turbine generators, diesel engine generators, electrical switchgear, cables, circuit breakers, boilers, piping, valves, pumps, motors and chillers. The data collection process and the resultant data are the subject of this paper

P. S. Hale; R. G. Arno; D. D. Dylis

2005-01-01

364

The power law character of off-site power failures  

E-print Network

A study on the behavior of off-site AC power failure recovery times at three nuclear plant sites is presented. It is shown, that power law is appropriate for the representation of failure frequency-duration correlation function of off-site power failure events, based on simple assumptions about component failure and repair rates. It is also found that the annual maxima of power failure duration follow Frechet distribution, which is a type II asymptotic distribution, strengthening our assumption of power law for the parent distribution. The extreme value distributions obtained are used to extrapolate for failure durations beyond the observed range.

Arul, A J; Marimuthu, S; Singh, O P; Singh, Om Pal

2003-01-01

365

Modified Newton-Raphson load flow analysis for integrated AC\\/DC power systems  

Microsoft Academic Search

The significant increase in planned offshore wind parks and the tendency towards large parks in considerable distances offshore, make the well established HVDC technology a favorable solution for the connection of these large & distant offshore wind parks to the main power grid onshore. It is therefore necessary to adequately model the HVDC transmission links and integrate them in the

A. Panosyan; B. R. Oswald

2004-01-01

366

An investigation of harmonics attenuation and diversity among distributed single-phase power electronic loads  

Microsoft Academic Search

Widely distributed single-phase power electronic loads arc an increasingly important source of harmonics in power distribution systems. The objective of this paper is to investigate the cumulative harmonic current characteristics of a large number of such loads. A complete analytical model for the most common load type is derived. This model is then used to investigate the impact of (1)

A. Mansoor; W. M. Grady; A. H. Chowdhury; M. J. Samotyj

1995-01-01

367

Systems analysis of the space shuttle. [communication systems, computer systems, and power distribution  

NASA Technical Reports Server (NTRS)

Developments in communications systems, computer systems, and power distribution systems for the space shuttle are described. The use of high speed delta modulation for bit rate compression in the transmission of television signals is discussed. Simultaneous Multiprocessor Organization, an approach to computer organization, is presented. Methods of computer simulation and automatic malfunction detection for the shuttle power distribution system are also described.

Schilling, D. L.; Oh, S. J.; Thau, F.

1975-01-01

368

A Better Steam Engine: Designing a Distributed Concentrating Solar Combined Heat and Power System  

E-print Network

A Better Steam Engine: Designing a Distributed Concentrating Solar Combined Heat and Power System of analysis of Distributed Concentrating Solar Combined Heat and Power (DCS-CHP) systems is a design that is predicted to convert sunlight to heat at 8-10% solar-electric efficiency while simultaneously capturing ~60

California at Berkeley, University of

369

ADAPTIVE DISTRIBUTED ALGORITHMS FOR POWER-EFFICIENT DATA GATHERING IN SENSOR NETWORKS  

E-print Network

ADAPTIVE DISTRIBUTED ALGORITHMS FOR POWER-EFFICIENT DATA GATHERING IN SENSOR NETWORKS Jugoslava A In this work, we consider the problem of designing adaptive distributed processing algorithms in large sensor, in sensor networks, since the sensors are strongly con- strained in terms of battery power [4], a meaningful

Cristescu, Razvan

370

Injection-Locked Clocking: A Low-Power Clock Distribution Scheme for High-End Microprocessors  

E-print Network

Injection-Locked Clocking: A Low-Power Clock Distribution Scheme for High-End Microprocessors Hui-performance microprocessors. Clocking circuitry accounts for an overwhelming amount of total power consumption in multi is a crucial aspect of modern multi- GHz microprocessor design. Conventional distribution schemes are more

Wu, Hui

371

Atmospheric Environment 40 (2006) 55085521 Air quality impacts of distributed power generation in the South  

E-print Network

. Keywords: Distributed power generation; Air quality modeling; Ozone; PM2.5; South Coast Air BasinAtmospheric Environment 40 (2006) 5508­5521 Air quality impacts of distributed power generation lead to increased levels of in-basin pollutants and adversely impact urban air quality. This study

Dabdub, Donald

372

Power flow control of a single distributed generation unit with nonlinear local load  

Microsoft Academic Search

Distributed generation units with small energy sources, such as fuel cells, micro-turbines, and photovoltaic devices, can be connected to utility grid as alternative energy sources besides providing power to their local loads. The distributed generation units are interfaced with utility grid using three phase inverters. With inverter control, both active and reactive power pumped into the utility grid from the

Min Dai; Mohammad N. Marwali; Jin-woo Jung; Ali Keyhani

2004-01-01

373

Advanced voltage regulation method of power distribution systems interconnected with dispersed storage and generation systems  

Microsoft Academic Search

This paper deals with an issue of voltage regulation for power distribution systems interconnected with dispersed storage and generation (DSG) systems. Since DSGs within power distribution systems impact on the conventional voltage regulation method, there is a possibility that customers' voltages violate the permissible limits. A multiple line drop compensation (MLDC) voltage regulation method that determines tap positions of under-load

Joon-Ho Choi; Jae-Chul Kim

2001-01-01

374

Voltage regulator modeling for the three-phase power flow in distribution networks  

Microsoft Academic Search

In this paper a three-phase power flow for electrical distribution systems considering different models of voltage regulators is presented. A voltage regulator (VR) is an equipment that maintains the voltage level in a predefined value in a distribution line in spite of the load variations within its nominal power. Three different types of connections are analyzed: 1) wye- connected regulators,

L. A. Gallego; A. Padilha-Feltrin

2008-01-01

375

Analysis and design of electronic transformers for electric power distribution system  

Microsoft Academic Search

A transformer performs many functions such as voltage transformation, isolation and noise decoupling, and it is an indispensable component in electric power distribution systems. However, at low frequencies (60\\/50 Hz), it is a bulky and expensive component. In this paper, the concept of electronic transformers is further extended and explored for its suitability in power distribution systems. It should be

Moonshik Kang; Prasad N. Enjeti; Ira J. Pitel

1999-01-01

376

Cascaded 5-level inverter type DSTATCOM for power quality improvement  

Microsoft Academic Search

In energy transmission systems, effective equipments on power control are generally known as Flexible AC Transmission System (FACTS). In addition, the power electronics-based equipment, which are called power conditioners are use to solve power quality problems. Since the topologies of these equipments are similar to those used in FACTS equipment, power conditioners are also called Distribution FACTS (DFACTS). DSTATCOM is

G. V. R. Satyanarayana; S. N. V. Ganesh

2010-01-01

377

Integrated power conversion for DC power system by flying capacitor multi-level converter  

Microsoft Academic Search

In a modern electrical power system, most of equipments have dc terminals as an interface or inside of them, but the electric power is distributed by ac. Therefore, they have to employ a power converter suitable for their circumstances to trade the electric power. However, as the converters cannot avoid conversion losses inherently, it is important to reduce the number

M. Hojo; K. Minato

2010-01-01

378

AC powered reactive magnetron deposition of indium tin oxide (ITO) films from a metallic target  

Microsoft Academic Search

Transparent highly conductive indium tin oxide (ITO) films for low cost applications were deposited by a reactive dual magnetron sputter process using metallic targets. The magnetrons were equipped with rectangular (130×400 mm2) In:Sn targets (90 wt.% In\\/10 wt.% Sn). A sine wave power supply was used at a frequency of about 70 kHz. All experiments were done in the transition mode at a constant

H. Kupfer; R. Kleinhempel; B. Graffel; Th. Welzel; Th. Dunger; F. Richter; W.-M. Gnehr; T. Kopte

2006-01-01

379

A High Power Density DC-DC Converter for Distributed PV Architectures  

SciTech Connect

In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

Mohammed S. Agamy; Song Chi; Ahmed Elasser; Maja Harfman-Todorovic; Yan Jiang; Frank Mueller; Fengfeng Tao

2012-06-01

380

Distributed topology control for power efficient operation in multihop wireless ad hoc networks  

Microsoft Academic Search

The topology of wireless multihop ad hoc networks can be controlled by varying the transmission power of each node. We propose a simple distributed algorithm where each node makes local decisions about its transmission power and these local decisions collectively guarantee global connectivity. Specifically, based on the directional information, a node grows it transmission power until it finds a neighbor

Roger Wattenhofer; L. Li; P. Bahl; Y.-M. Wang

2001-01-01

381

1464 IEEE TRANSACTIONS ON SMART GRID, VOL. 4, NO. 3, SEPTEMBER 2013 Distributed Optimal Power Flow  

E-print Network

1464 IEEE TRANSACTIONS ON SMART GRID, VOL. 4, NO. 3, SEPTEMBER 2013 Distributed Optimal Power Flow for Smart Microgrids Emiliano Dall'Anese, Member, IEEE, Hao Zhu, Member, IEEE, and Georgios B. Giannakis of minimizing either the power distribu- tion losses, or, the cost of power drawn from the substation and sup

Giannakis, Georgios

382

Smart power flow control in DC distribution systems involving sustainable energy sources  

Microsoft Academic Search

In this paper, a detailed description of a proposed technique for power flow control in DC distribution systems has been presented. The DC system under study is assumed mainly dependent on renewable energy sources. The proposed topology utilizes a controlled series current compensator (CSCC) technique for connection and power flow control among buses. The proposed topology allows full power flow

A. Mohamed; O. Mohammed

2010-01-01

383

Study of temperature distribution of a pyramidal EM-wave absorber under high power injection  

Microsoft Academic Search

Utilization of electromagnetic absorbers under high power is increasing. The absorbers are used in anechoic chambers for estimation of performance of high power radars. Variation of the absorption characteristics of the absorbers under such condition is expected, due to the generation of heat or temperature change. In this paper, first temperature distribution of a pyramidal EM-wave absorber under high power

Shinya Watanabe; Tetsuhiro Sasagawa; Osamu Hashimoto; Toshifumi Saito

2007-01-01

384

Analysis and minimization of losses in electric-power transmission and distribution systems  

Microsoft Academic Search

A comprehensive approach is taken to the loss analysis and minimization in electrical power systems at both transmission and distribution levels. New methods were developed to calculate the power and energy losses in bulk-power transmission systems. The methods incorporate the effect of the actual on-line control and operation of the system to improve the accuracy of calculations. To calculate the

Baran

1988-01-01

385

A Refined Regulation Model for Incentive Regulation of Electric Power Transmission and Distribution  

Microsoft Academic Search

After the reform of the electrical power industry, the vertical integration management control method has been accepted by the electric power transmission and distribution firms in China, where necessary supervision and control are needed. In this paper, the author firstly investigates the existing research studies and the current regulation methods of international electric power market and then proposes a refined

Liu Faquan; Zhang Huifeng

2009-01-01

386

A Partitioning Approach for Parallel Simulation of AC-Radial Shipboard Power Systems  

E-print Network

............................................. 122 Fig. 3.3.10. Interaction between C# and Mathematica ................................................... 127 Fig. 3.3.11. Activity diagram illustrating steps to balance graph ................................... 128 Fig. 3.3.12. Component sets... output file from Mathematica ........................................... 129 Fig. 3.4.1. Illustration of subsystem simulation on a multicore processor ..................... 131 Fig. 3.4.2. Examples of various subsystem/thread distributions on four cores...

Uriarte, Fabian Marcel

2011-08-08

387

Integrated Network Security Protocol Layer for Open-Access Power Distribution Systems  

Microsoft Academic Search

Power distribution system cyber-security concerns are increasing rapidly with growing demands for open accesses to the distribution systems for electricity generation and trading imposed by new government deregulations. This paper proposes a new integrated network security protocol layer, located below the data-link layer of DNP3 - a popular utility protocol, to enhance the data transmission cyber-security for power distribution systems.

Todd Mander; Farhad Nabhani; Lin Wang; Richard Cheung

2007-01-01

388

Modeling and Analysis of Power Distribution Networks for Gigabit Applications  

E-print Network

, the macromodel of the planes, transmission lines, and nonlinear drivers have been simulated in standard SPICE-based circuit simulators for computing power supply noise. In addition to noise computation, the self an alarming increase in the power consumed by microprocessors. Since computers are broadband systems

Swaminathan, Madhavan

389

Distributed algorithms for transmission power control in wireless sensor networks  

Microsoft Academic Search

In a wireless, multi-hop sensor network, choosing transmission power levels has an important impact on energy efficiency and network lifetime. Two algorithms for dynamically adjusting transmission power level on a per-node basis are proposed here. Network lifetime, convergence speed as well as resulting network connectivity are used as figures of merit for these two algorithms. They have been evaluated in

Martin Kubisch; Holger Karl; Adam Wolisz; Lizhi Charlie Zhong; Jan Rabaey

2003-01-01

390

An intelligent on line voltage regulation in power distribution system  

Microsoft Academic Search

In a reliable power system one of the most important requirements is to maintain the voltage at consumer premises within permissible ranges to ensure high quality of customer service. Since the voltage profile is consistently varied by load fluctuations hence it should be controlled by voltage regulators. Voltage stability and power quality of electrical systems depend on the proper voltage

Shrabani Pal; Sudipta Nath

2010-01-01

391

Ac-ac dual active bridge converter for solid state transformer  

Microsoft Academic Search

This work investigates the application of an ac-ac dual active bridge converter for solid state transformer. The proposed converter topology consists of two active H-bridges and one high frequency transformer. Four-quadrant switch cells are used to ensure bi-directional power flow. The advantages of direct ac-ac conversion include fewer power conversion stages and minimized passive components. The ac-ac dual active bridge

Hengsi Qin; Jonathan W. Kimball

2009-01-01

392

Mini-Scale Power Distribution Network Feeding Trapezoidal-Wave Voltages to Power Electronic Loads with Diode Rectifiers  

NASA Astrophysics Data System (ADS)

This paper proposes a novel three-phase power distribution system feeding trapezoidal voltages to various power electronic loads with diode rectifier front-ends. The network distributes trapezoidal voltages generated by synchronous superposition of wave-shaping voltages onto sinusoidal voltages available from a utility power grid. The power distribution by the trapezoidal voltages allows reducing harmonics of the line currents without electronic switching devices because of a spontaneously widened conduction period of the current waveforms. The reduction of the harmonic currents also contributes to improve total power factor at the load input terminals and efficiency of the power transmission cables. Since the diodes of the rectifiers successively commutate the trapezoidal waves during periods of their flat parts, not only total harmonic distortion of the currents is improved, but also voltage ripple across the dc-buses of the rectifiers can effectively be reduced with less filter capacitors. In addition, the system offers an uninterruptible power supply function by immediately changing its outputs from the wave-shaping voltages to the trapezoidal voltages when interruption occurs in the power grid. In this paper, a prototype of the system is experimentally examined from various angles of operating characteristics and test results are presented to prove feasibility of the proposed system.

Noguchi, Toshihiko; Imoto, Masaru; Sato, Yoshikazu

393

Low Insertion HVDC Circuit Breaker: Magnetically Pulsed Hybrid Breaker for HVDC Power Distribution Protection  

SciTech Connect

GENI Project: General Atomics is developing a direct current (DC) circuit breaker that could protect the grid from faults 100 times faster than its alternating current (AC) counterparts. Circuit breakers are critical elements in any electrical system. At the grid level, their main function is to isolate parts of the grid where a fault has occurred—such as a downed power line or a transformer explosion—from the rest of the system. DC circuit breakers must interrupt the system during a fault much faster than AC circuit breakers to prevent possible damage to cables, converters and other grid-level components. General Atomics’ high-voltage DC circuit breaker would react in less than 1/1,000th of a second to interrupt current during a fault, preventing potential hazards to people and equipment.

None

2012-01-09

394

Modeling and analysis of AC line conditioner based on three-phase PWM Cuk AC-AC converter  

Microsoft Academic Search

In this paper, the characteristics of an AC line conditioner based on three-phase PWM Cuk AC-AC converter are analyzed. The PWM Cuk AC-AC converter is modeled by using complex D Q circuit transformation whereby the important characteristic equations such as voltage gain, input power factor, and the interested voltages and\\/or currents can be analytically obtained. Moreover, AC analysis is given

Nam-Sup Choi; Yulong Liz

2004-01-01

395

Power components for the space station 20kHz power distribution system  

Microsoft Academic Search

Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of The Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus

David D. Renz

1988-01-01

396

Impact of Winding Layer Number and Slot\\/Pole Combination on AC Armature Losses of Synchronous Surface PM Machines Designed for Wide Constant-Power Speed Range Operation  

Microsoft Academic Search

This paper examines the impact of the winding layer number (single- and double-layer), and magnet type (sintered and bonded), as well as slot\\/pole combinations on AC stator losses in surface permanent magnet (SPM) synchronous machines equipped with fractional-slot concentrated windings that are designed for wide speed ranges of constant-power operation. It is shown that the use of bonded magnets instead

Patel B. Reddy; T. M. Jahns; Ayman M. El-Refaie

2008-01-01

397

AC-DC Power-Factor-Corrected Switching Converter Based on Air-Gap Transformer and Pulse Position Modulator for Lighting Applications  

Microsoft Academic Search

In this paper an AC-DC power-factor-corrected switching converter based on pulse position modulator (PPM) is realized and applied to drive LED array. The PPM is realized using a Timer, which consists of a comparator and one RS flip-flop. The Timer is connected as an oscillator of lowfrequency around 5 kHz. The pulse position varies with the input rectified-voltage as modulating

Roberto Baca; Gabriel Romero Paredes; Ramon Pena

2011-01-01

398

A single-stage power factor correction AC\\/DC converter based on zero voltage switching full bridge topology with two series-connected transformers  

Microsoft Academic Search

A single-stage power factor correction ac\\/dc converter based on zero voltage switching (ZVS) full bridge topology with two series-connected transformers is proposed in this paper. The proposed converter offers a very wide ZVS range due to the configuration of two series-connected transformers. It features a high efficiency over wide load ranges. Furthermore, it shows the low voltage stress on a

Tae-Sung Kim; Gwan-Bon Koo; Gun-Woo Moon; Myung-Joong Youn

2006-01-01

399

A novel multicell DC-AC converter for applications in renewable energy systems  

Microsoft Academic Search

This paper presents a novel DC-AC converter for applications in the area of distributed energy generation systems, e.g., solar power systems, fuel-cell power systems in combination with supercapacitor or battery energy storage. The proposed converter is realized using an isolated multicell topology where the total AC output of the system is formed by series connection of several full-bridge converter stages.

Hans Ertl; Johann W. Kolar; Franz C. Zach

2002-01-01

400

Power distribution control coordinating ultracapacitors and batteries for electric vehicles  

Microsoft Academic Search

Electrical energy storage is a central element to any electric-drivetrain technology - whether hybrid-electric, fuel-cell, or all-electric. A particularly cost-sensitive issue with energy storage is the high replacement cost of depleted battery banks. One possibility to ease the power burden on batteries and fuel cells is to use ultra-capacitors as load-leveling devices. The high power density of ultra-capacitors allows a

Evren Ozatay; Ben Zile; Joel Anstrom; Sean Brennan

2004-01-01

401

Globally Optimal Distributed Power Control for Nonconcave Utility Maximization  

Microsoft Academic Search

Future wireless networks are expected to operate in dense environments where\\u000athe system capacity is fundamentally limited by severe co-channel interference\\u000aamong neighboring links. Transmit-power control has been recently explored as\\u000aan important interference-mitigation technique that aims to maximize a system\\u000aefficiency metric, which is often measured by a system utility function.\\u000aOptimal power control is known to be difficult

Li Ping Qian; Ying Jun Zhang; Mung Chiang

2010-01-01

402

Mixed-signal noise-decoupling via simultaneous power distribution design and cell customization in RAIL  

Microsoft Academic Search

An important and largely unexplored aspect of power distribution synthesis is cell customization. Through cell customization, power I\\/O cell assignments and local substrate and power supply decoupling may be tailored to reduce deleterious noise effects on analog circuits in mixed-signal environments. In this paper, we describe techniques for simultaneous power grid design (topology and sizing) and cell configuration\\/customization which allow

B. R. Stanisic; Rob A. Rutenbar; L. Richard Carley

1994-01-01

403

Development of Ada language control software for the NASA power management and distribution test bed  

NASA Technical Reports Server (NTRS)

The Ada language software developed to control the NASA Lewis Research Center's Power Management and Distribution testbed is described. The testbed is a reduced-scale prototype of the electric power system to be used on space station Freedom. It is designed to develop and test hardware and software for a 20-kHz power distribution system. The distributed, multiprocessor, testbed control system has an easy-to-use operator interface with an understandable English-text format. A simple interface for algorithm writers that uses the same commands as the operator interface is provided, encouraging interactive exploration of the system.

Wright, Ted; Mackin, Michael; Gantose, Dave

1989-01-01

404

Power factor improvement study for an electrical power distribution system for University of California, Lawrence Livermore National Laboratory, Livermore, California  

SciTech Connect

This report summarizes the results, findings, methods of analysis, and recommendations of a power factor improvement study for the site electrical distribution system of the University of California, Lawrence Livermore National at Livermore, California. The purpose of this study is to determine a suitable means to improve the site power factor to at least an average of 95% in order to preserve the economic advantage of WAPA service.

Not Available

1983-12-01

405

Anode-cathode power distribution systems and methods of using the same for electrochemical reduction  

DOEpatents

Power distribution systems are useable in electrolytic reduction systems and include several cathode and anode assembly electrical contacts that permit flexible modular assembly numbers and placement in standardized connection configurations. Electrical contacts may be arranged at any position where assembly contact is desired. Electrical power may be provided via power cables attached to seating assemblies of the electrical contacts. Cathode and anode assembly electrical contacts may provide electrical power at any desired levels. Pairs of anode and cathode assembly electrical contacts may provide equal and opposite electrical power; different cathode assembly electrical contacts may provide different levels of electrical power to a same or different modular cathode assembly. Electrical systems may be used with an electrolyte container into which the modular cathode and anode assemblies extend and are supported above, with the modular cathode and anode assemblies mechanically and electrically connecting to the respective contacts in power distribution systems.

Koehl, Eugene R; Barnes, Laurel A; Wiedmeyer, Stanley G; Williamson, Mark A; Willit, James L

2014-01-28

406

Analysis of Power Quality Based on Real Data and Quality Improvement at Campus Distribution System  

NASA Astrophysics Data System (ADS)

In recent years, a lot of equipments have been made using the inverter technology from home electric appliances to office automation apparatuses and industrial equipments with the development of power electronics technology. The voltage distortion of a distribution system has increased due to the harmonic currents generated from these apparatuses, and the increase in harmonics continues to be expected. In addition, the distribution system forms the circuit of harmonic distortion expansion by the prevalence of static capacitor without L for power factor improvement. Moreover, the voltage imbalance occurs by diversification of loads or imbalanced connection of single-phase loads. The deterioration of power quality in the distribution system causes various problems such as the overheating of equipments and malfunction of rotating machines. Since the power quality changes according to air temperature and date, it is desirable to measure the voltages and currents continuously for a long time. In this study, the authors focus attention on the distribution system in the University of Fukui campus, and the authors have measured the voltages and currents in the distribution system for a long period with WAMS (Wide Area Measurement System) using NCT (Network Computing Terminal). Based on the obtained data, the authors analyzed the power quality of the campus distribution system from viewpoints of voltage imbalance, current imbalance, voltage THD (Total Harmonic Distortion), and current THD. Furthermore, the improvement effect of power quality of the campus distribution system by exchange of single-phase load connection is described.

Kawasaki, Shoji; Matsuki, Junya; Hayashi, Yasuhiro; Ito, Akitoshi

407

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

SciTech Connect

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

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

2002-11-01

408

82 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS, PART 1, VOL. 47, NO. 1, JANUARY 2000 Fig. 5. Output voltage waveform in the closed-loop dc-ac power inverter.  

E-print Network

devices from dc sources, such as cars or recreational vehicles, or in uninterruptible power supplies voltage waveform in the closed-loop dc-ac power inverter. Horizontal scale: 5 ms/div.; vertical scale: 0.2 V/div. Fig. 6. Bode plots of the closed-loop power inverter . Packard 4194A Network Analyzer, Bode

Leuciuc, Adrian

409

COMMUNICATION SYSTEMS AND STUDY METHOD FOR ACTIVE DISTRIBUTION POWER SYSTEMS  

E-print Network

of communication systems, and the main communication technologies and protocols on each corresponding layer are introduced. Some newly developed communication techniques, like Ethernet, are discussed with reference and the power system depend on many aspects, such as related protocols, access technologies, and transmission

Chen, Zhe

410

Protecting Intelligent Distributed Power Grids against Cyber Attacks  

SciTech Connect

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.

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

2010-12-31

411

Distributed SCADA system for optimization of power generation  

Microsoft Academic Search

According to the International Energy Agency (IEA) the worldpsilas energy needs would be well over 50% higher in 2030 than today at an average annual rate of 1.8% per year. Modern Information Technology based Supervisory Control and Data Acquisition Systems (SCADA) assume greater significance in this context to derive maximum efficiency in power plant operations by ensuring optimal use of

S. R. Valsalam; A. Sathyan; S. S. Shankar

2008-01-01

412

Microgrids, virtual power plants and our distributed energy future  

SciTech Connect

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

Asmus, Peter

2010-12-15

413

Voltage multi-stability in distribution grids with power flow reversal  

E-print Network

High levels of penetration of distributed generation and aggressive reactive power compensation with modern power electronics may result in the reversal of active and reactive power flows in future distribution grids. The voltage stability of these operating conditions may be very different from the more traditional power consumption regime. We study the stability characteristics of distribution networks with reversed power flow. After introducing a universal algebraic approach to characterize all the solutions of the power flow equations, we show that new solutions appear in the reversed power flow regime even in the simplest three bus systems. We show that the some of these solutions are stable and the system may exhibit a phenomenon of multistability, where multiple stable equilibria co-exist at the given set of parameters, and the system may converge to an undesirable equilibrium after a disturbance. These predictions are validated with dynamic simulations of two different systems. Under certain conditions the new states are viable and may be characterized by relatively high voltages. Possible approaches towards reactive power/voltage regulation as well as permissible distributed generation capacity in future power systems are proposed and discussed in the end of the paper.

Hung D. Nguyen; Konstantin Turitsyn

2014-07-08

414

A new numerical approach to find current distribution and AC losses in coaxial assembly of twisted HTS tapes in single layer arrangement  

NASA Astrophysics Data System (ADS)

This paper presents a novel technique for evaluating AC losses and current distribution in single layer assemblies of coaxially wound thin conductors, such as YBCO coated conductors. The proposed approach takes into account the twisted geometry of the individual superconducting tapes by considering the integral relation between the magnetic vector potential and the current density in the tapes (Biot-Savart formula). The integrals are solved numerically and semi-analytically, and the results are used to generate a discretized system of equations based on the magnetic flux diffusion equation (eddy current problem). The latter is solved using an efficient time transient solver (DASPK). It is assumed that, due to the helical symmetry of the problem, it is sufficient to solve for the current distribution in half of a single tape cross-section, even if many tapes are present, which allows a drastic reduction of the 3-D problem to a simple 1-D domain. The method was used to evaluate the AC losses of a HTS cable made of coated conductors, and it was observed that for a given radius of the former and number of tapes, twisted tapes with smaller pitch have lower AC losses.

Siahrang, Majid; Sirois, Frédéric; Grilli, Francesco; Babic, Slobodan; Brault, Simon

2010-06-01

415

Asynchronous Distributed Power Iteration with Gossip-based Normalization  

E-print Network

the iteration component. The norm of the re- sulting vector is an unknown finite constant by default; however the correctness, the performance and the fault tolerance of the protocol. 1 Introduction The calculation. In recent years, eigenvector calculation has found new and important applications in fully distributed

Jelasity, Márk

416

Distributed Leadership: The Uses and Abuses of Power  

ERIC Educational Resources Information Center

In about a decade the theory of distributed leadership has moved from a tool to better understand the ecology of leadership to a widely prescribed practice. This article considers how to account for its spread and dominance and what purpose it serves. The concept offers an enticing suggestion of including more in leadership, and even sometimes…

Lumby, Jacky

2013-01-01

417

Constraining the Power Spectrum Using the Column Density Distribution: a Status Report  

E-print Network

We review the arguments for how the slope of the column density distribution of the Lyman-alpha forest should depend on the matter power spectrum. The latest progress, presented by various groups in this conference and elsewhere, is summarized.

Lam Hui

1997-12-04

418

GENERIC VERIFICATION PROTOCOL: DISTRIBUTED GENERATION AND COMBINED HEAT AND POWER FIELD TESTING PROTOCOL  

EPA Science Inventory

This report is a generic verification protocol by which EPA?s Environmental Technology Verification program tests newly developed equipment for distributed generation of electric power, usually micro-turbine generators and internal combustion engine generators. The protocol will ...

419

On the distributions of seasonal river flows: Lognormal or power law?  

NASA Astrophysics Data System (ADS)

Distributional analysis of river discharge time series is an important task in many areas of hydrological engineering, including optimal design of water storage and drainage networks, management of extreme events, risk assessment for water supply, and environmental flow management, among many others. Having diverging moments, heavy-tailed power law distributions have attracted widespread attention, especially for the modeling of the likelihood of extreme events such as floods and droughts. However, straightforward distributional analysis does not connect well with the complicated dynamics of river flows, including fractal and multifractal behavior, chaos-like dynamics, and seasonality. To better reflect river flow dynamics, we propose to carry out distributional analysis of river flow time series according to three "flow seasons": dry, wet, and transitional. We present a concrete statistical procedure to partition river flow data into three such seasons and fit data in these seasons using two types of distributions, power law and lognormal. The latter distribution is a salient property of the cascade multiplicative multifractal model, which is among the best models for turbulence and rainfall. We show that while both power law and lognormal distributions are relevant to dry seasons, river flow data in wet seasons are typically better fitted by lognormal distributions than by power law distributions.

Bowers, M. C.; Tung, W. W.; Gao, J. B.

2012-05-01

420

The Column Density Distribution of the Lyman-Alpha Forest: A Measure of Small Scale Power  

E-print Network

Absorption lines in the Lyman-alpha forest can be thought of as peaks in neutral hydrogen density along lines of sight. The column density distribution (the number density of absorption lines as a function of column density) is then a statistic of density peaks, which contains information about the underlying power spectrum. In particular, we show that the slope of the distribution provides a measure of power on scales smaller than those probed by studies of present-day large scale structure.

Lam Hui; Nickolay Y. Gnedin; Yu Zhang

1997-02-19

421

An adaptive algorithm for the detection of high impedance faults on power distribution systems  

E-print Network

AN ADAPTIVE ALGORITHM FOR THE DETECTION OF HIGH IMPEDANCE FAULTS ON POWER DISTRIBUTION SYSTEMS A Thesis by KURT ERIC MCCALL Submitted to the Office of Graduate Studies of Texas AkM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1990 Major Subject, : Electrical Engineering AN ADAPTIVE ALGORITHM FOR THE DETECTION OF HIGH IMPEDANCE FAULTS ON POWER DISTRIBUTION SYSTEMS A thesis by KURT ERIC MCCALL Approved as to style and content by...

McCall, Kurt Eric

1990-01-01

422

Explaining the Power-law Distribution of Human Mobility Through Transportation Modality Decomposition  

E-print Network

Human mobility has been empirically observed to exhibit Levy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we analyze urban human mobility and we propose to explain the Levy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bicycle, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an e...

Zhao, Kai; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

2014-01-01

423

Space power distribution system technology. Volume 1: Reference EPS design  

NASA Technical Reports Server (NTRS)

The multihundred kilowatt electrical power aspects of a mannable space platform in low Earth orbit is analyzed from a cost and technology viewpoint. At the projected orbital altitudes, Shuttle launch and servicing are technically and economically viable. Power generation is specified as photovoltaic consistent with projected planning. The cost models and trades are based upon a zero interest rate (the government taxes concurrently as required), constant dollars (1980), and costs derived in the first half of 1980. Space platform utilization of up to 30 years is evaluated to fully understand the impact of resupply and replacement as satellite missions are extended. Such lifetimes are potentially realizable with Shuttle servicing capability and are economically desirable.

Decker, D. K.; Cannady, M. D.; Cassinelli, J. E.; Farber, B. F.; Lurie, C.; Fleck, G. W.; Lepisto, J. W.; Massner, A.; Ritterman, P. F.

1983-01-01

424

A power electronic transformer for PWM AC drive with lossless commutation and common-mode voltage suppression  

Microsoft Academic Search

This paper presents a novel dc\\/ac converter topology with a high frequency transformer-link for three-phase adjustable magnitude and frequency PWM ac drives. Such drives find wide range of applications including UPS systems and drives involving renewable energy sources like solar and fuel cells. One recent potential area of application is renewable energy sources like wind or wave connected with HVDC

Kaushik Basu; N. Mohan

2010-01-01

425

The Impact of Distributed Generation on Power Transmission Grid Dynamics D. E. Newman B. A. Carreras M. Kirchner I. Dobson  

E-print Network

The Impact of Distributed Generation on Power Transmission Grid Dynamics D. E. Newman B. A. The generation power is automatically increased when the capacity margin is below a given critical level. Using allows us to vary: 1) fraction of power from distributed generation 2) fraction of nodes with distributed

Dobson, Ian

426

SELECTING THE BEST POINT OF CONNECTION FOR SHUNT ACTIVE FILTERS IN MULTI-BUS POWER DISTRIBUTION SYSTEMS  

E-print Network

by considering the power system topology and load distribution. It is important to note, that if the shunt active to the power distribution system, the point of connection must be carefully selected so the generated harmonic an analytical procedure based in the power distribution system voltage and current transfer matrices is derived

Catholic University of Chile (Universidad Católica de Chile)

427

Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants  

DOEpatents

A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

2014-09-09

428

Independent Orbiter Assessment (IOA): Analysis of the electrical power distribution and control/electrical power generation subsystem  

NASA Technical Reports Server (NTRS)

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C)/Electrical Power Generation (EPG) hardware. The EPD and C/EPG hardware is required for performing critical functions of cryogenic reactant storage, electrical power generation and product water distribution in the Orbiter. Specifically, the EPD and C/EPG hardware consists of the following components: Power Section Assembly (PSA); Reactant Control Subsystem (RCS); Thermal Control Subsystem (TCS); Water Removal Subsystem (WRS); and Power Reactant Storage and Distribution System (PRSDS). The IOA analysis process utilized available EPD and C/EPG hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode.

Patton, Jeff A.

1986-01-01

429

Magnetic Resonant Wireless Power Delivery for Distributed Sensor and Wireless Systems  

E-print Network

Magnetic Resonant Wireless Power Delivery for Distributed Sensor and Wireless Systems Brian J. Lee, Pittsburgh, PA 15213 Abstract-- In this paper we report on a resonant wireless power delivery system using a resonant circuit and one or more repeater, or relay, resonant tanks that couple energy from source coil

Cervesato, Iliano

430

Synchronization Methods for Three Phase Distributed Power Generation Systems. An Overview and Evaluation  

Microsoft Academic Search

Nowadays, it is a general trend to increase the electricity production using distributed power generation systems (DPGS) based on renewable energy resources such as wind, sun or hydrogen. Jf these systems are not properly controlled, their connection to the utility network can generate problems on the grid side. Therefore, considerations about power generation, safe running and grid synchronization must be

Adrian Timbus; Remus Teodorescu; Frede Blaabjerg; Marco Liserre

2005-01-01

431

Power distribution system design methodology and capacitor selection for modern CMOS technology  

Microsoft Academic Search

Power systems for modern complementary metal-oxide-semiconductor (CMOS) technology are becoming harder to design. One design methodology is to identify a target impedance to be met across a broad frequency range and specify components to meet that impedance. The impedance versus frequency profiles of the power distribution system components including the voltage regulator module, bulk decoupling capacitors and high frequency ceramic

Larry D. Smith; Raymond E. Anderson; Douglas W. Forehand; Thomas J. Pelc; Tanmoy Roy

1999-01-01

432

Maximum Effective Distance of On-Chip Decoupling Capacitors in Power Distribution Grids  

E-print Network

Maximum Effective Distance of On-Chip Decoupling Capacitors in Power Distribution Grids Mikhail@freescale.com ABSTRACT Decoupling capacitors are widely used to reduce power sup- ply noise. On-chip decoupling capacitors have traditionally been allocated into the available white space on a die. The efficacy

Friedman, Eby G.

433

A Study on Optimal Sizing of Superconducting Magnetic Energy Storage in Distribution Power System  

Microsoft Academic Search

This paper proposes a method to determine the optimal size of superconducting magnetic energy storage (SMES) to improve the stability of distribution power system with photovoltaic (PV) generation. The output power of PV system fluctuates according to changing weather conditions. Then, the system is subject to be unstable. In order to improve its stability, the SMES is applied. In general,

Byung-Kwan Kang; Seung-Tak Kim; Byung-Chul Sung; Jung-Wook Park

2012-01-01

434

Using Batteries to Reduce the Power Costs of Internet-scale Distributed  

E-print Network

Using Batteries to Reduce the Power Costs of Internet-scale Distributed Networks Darshan SDemand(KWs) Energy (KWHs) #12;Key Idea: Use batteries to reduce the power supply from Psupply to Pbatt (+ safety), cb = cost of battery ($/KWH), B= battery size, L = battery lifetime. #12;Alternate view: Use

Berger, Emery

435

Distributing Power to Electric Vehicles on a Smart Grid Yingjie Zhou*,  

E-print Network

Distributing Power to Electric Vehicles on a Smart Grid Yingjie Zhou*, , Student Member, IEEE.edu Abstract--Electric vehicles create a demand for additional electrical power. As the popularity of electric. However, in the interim the rate at which electric vehicles can be deployed will depend on our ability

Maxemchuk, Nicholas F.

436

Experimental determination of the MHD-EMP effects on power distribution transformers  

Microsoft Academic Search

It is a well-established fact that geomagnetic storms influence electrical power transmission and distribution systems. Previous cases of such storms in the northern latitudes have resulted in occasional power disruptions, and in some cases, damage to transformers. These effects are caused by a time variation of the earth's magnetic field creating an induced electric field along the surface of the

B. W. McConnell; Paul R. Barnes; Frederick M. Tesche

1991-01-01

437

A fully integrated 60GHz distributed transformer power amplifier in bulky CMOS 45nm  

Microsoft Academic Search

This paper describes a fully integrated differential power amplifier (PA) operating at 60 GHz ISM band and implemented in 45nm CMOS technology. The PA is based on a distributed active transformer (DAT) topology which enables simultaneous power combining and realization of an efficient impedance matching. To cope with the asymmetric nature of DAT, resulting in common-mode and unequal differential voltage-

Jaap Essing; Reza Mahmoudi; Yu Pei; Arthur van Roermund

2011-01-01

438

Performance for passive and active power filter in reducing harmonics in the distribution system  

Microsoft Academic Search

This paper presents the results for the performance of passive and active power filter to reduce harmonics in the distribution system. The harmonics analysis is performed in order to observe the percentage reduction of amplitude current harmonics and total harmonic distortion for passive and active power filter at various loads. In addition to that the bidirectional switching is used as

M. Izhar; C. M. Hadzer; M. Syafrudin; S. Taib; S. Idris

2004-01-01

439

Smart Wires — A distributed, low-cost solution for controlling power flows and monitoring transmission lines  

Microsoft Academic Search

Smart Wires is a family of three Distributed FACTS (D-FACTS) technologies able to realize low-cost transmission line monitoring and power flow control in meshed networks. Smart Wires will allow utilities to increase power transfers in meshed networks by increasing average line utilization. The technology is projected to have significantly lower cost and lead time than alternatives, namely new line construction,

Frank Kreikebaum; Debrup Das; Yi Yang; Frank Lambert; Deepak Divan

2010-01-01

440

Model predictive control for Cascaded H-bridge multilevel inverters with even power distribution  

Microsoft Academic Search

Cascaded H-bridge inverters are commonly controlled using linear control and Phase Shifted Pulse Width Modulation, since it allows an even power distribution among the cells, which reduces the harmonic distortion by means of isolation phase-shifted transformers. Recently, predictive control schemes for power electronic converters have been developed, featuring its simplicity, flexibility using different control objectives and an improved dynamic performance.

Alan Wilson; P. Corte?s; Samir Kouro; J. Rodri?guez; H. Abu-Rub

2010-01-01

441

Power distribution networks for system-on-package: status and challenges  

Microsoft Academic Search

The power consumption of microprocessors is increasing at an alarming rate leading to 2X reduction in the power distribution impedance for every product generation. In the last decade, high I\\/O ball grid array (BGA) packages have replaced quad flat pack (QFP) packages for lowering the inductance. Similarly, multilayered printed circuit boards loaded with decoupling capacitors are being used to meet

Madhavan Swaminathan; Joungho Kim; Istvan Novak; James P. Libous

2004-01-01

442

Power harvesting for smart sensor networks in monitoring water distribution system  

Microsoft Academic Search

Recently, there has been a growing interest in using wireless sensor networks for monitoring water distribution infrastructure to help drinking water utilities to have better understanding of hydraulic and water quality statement of their underground assets. One of the challenges is limited power resources for operating the smart sensors and sensor networks. Current common used power supplies for sensor node

M. I. Mohamed; W. Y. Wu; M. Moniri

2011-01-01

443

TRANSIENT CURRENTSAM) VOLTAGES IN A POWER DISTRIBUTION SYSTEM DUE TO NATURAL LIGHTNING  

E-print Network

aspectsof lightningand lightning protection. The facility is equipped with an unenergized, test powerTRANSIENT CURRENTSAM) VOLTAGES IN A POWER DISTRIBUTION SYSTEM DUE TO NATURAL LIGHTNING M and ComputerEngineering University of Florida Gainesville,Florida USA Abstract: Natural lightning occurred six

Florida, University of

444

Analysis and design of electronic transformers for electric power distribution system  

Microsoft Academic Search

A power transformer performs many functions such as voltage transformation, isolation, noise decoupling and is an indispensable component in electricity distribution systems. However, at low frequencies (60\\/50 Hz) it is a bulky and expensive component. In this paper, the concept of electronic transformers is further discussed. Several possible topologies employing static power converters connected on the primary and secondary side

Moonshik Kang; Prasad N. Enjeti; Ira J. Pitel

1997-01-01

445

The harmonic impact of variable speed air conditioners on residential power distribution  

Microsoft Academic Search

Power electronic circuits fed directly from electric utility power systems are often the source of significant harmonic currents. The susceptibility of residential power distribution systems to harmonics generated by inverter-driven variable-speed air conditioners, which are expected to see wider application in the future, is examined. In general, variable-speed air conditioners are 15-40% more energy efficient than comparable single-speed air conditioners.

Richard S. Wallace; A. Variable-Speed Air Conditioners

1992-01-01

446

Impact of Distributed Wind on Bulk Power System Operations in ISO-NE (Presentation)  

SciTech Connect

The work presented in the paper corresponding to this presentation aims to study the impact of a range of penetration levels of distributed wind on the operation of the electric power system at the transmission level. This presentation is an overview of a case study on the power system in Independent System Operator New England. It is analyzed using PLEXOS, a commercial power system simulation tool

Brancucci Martinez-Anido, C.; Hodge, B. M.; Palchak, D.; Miettinen, J.

2014-11-01

447

Calculated power distribution of a thermionic, beryllium oxide reflected, fast-spectrum reactor  

NASA Technical Reports Server (NTRS)

A procedure is developed and used to calculate the detailed power distribution in the fuel elements next to a beryllium oxide reflector of a fast-spectrum, thermionic reactor. The results of the calculations show that, although the average power density in these outer fuel elements is not far from the core average, the power density at the very edge of the fuel closest to the beryllium oxide is about 1.8 times the core avearge.

Mayo, W.; Lantz, E.

1973-01-01

448

A Distributed Channel Access Protocol for Ad Hoc Networks with Feedback Power Control  

Microsoft Academic Search

Distributed power control schemes are extensively employed in the cellular networks and are capable of improving the capacity of the network. However, the power control schemes from the cellular networks suffer from performance degradation due to self and direct-interference and hidden-terminal problems when directly employed in ad hoc networks. Most of the existing channel reservation-based power control protocols for ad

S. Hasan Raza Naqvi; Lalit M. Patnaik

2006-01-01

449

Distributed Internet-based Load Altering Attacks against Smart Power Grids  

E-print Network

distribution system. Keywords: Smart grid security, Internet-based load altering attacks, demand sideDistributed Internet-based Load Altering Attacks against Smart Power Grids Amir-Hamed Mohsenian management, cost-efficient load protection. I. INTRODUCTION The recent advancements in smart grid systems

Mohsenian-Rad, Hamed

450

A model of sturgeon distribution under a dam of a hydro-electric power plant  

Microsoft Academic Search

This article is dedicated to the question of passage of sturgeon through a dam of a hydro-electric power plant (HPP) during spawning migrations. A model of distribution of water velocity in the tail water of HPP was constructed. On the basis of this model a model of sturgeon distribution under a dam of HPP was created. The latter model was

V. I. Gertsev; V. V. Gertseva

1999-01-01

451

Optimal Power Allocation and Load Distribution for Multiple Heterogeneous Multicore Server  

E-print Network

Optimal Power Allocation and Load Distribution for Multiple Heterogeneous Multicore Server, and Ivan Stojmenovic, Fellow, IEEE Abstract--For multiple heterogeneous multicore server processors across distribution and balancing. Energy efficiency is one of the most important issues for large- scale server

Stojmenovic, Ivan

452

Assessment the connecting style of power distribution network based on fuzzy and blind number theory  

Microsoft Academic Search

The selection of the distribution network connection mode is the precondition and key base work for improving the technical and economic of the distribution system. To take into account the influence of uncertainties in power network expansion planning, the fuzzy and blind number theory is deduced and used for measurement and calculation of uncertain information which influence the final decision.

Yong-Xiu He; Wei Wang; Liang-Qi Wu; Fu-Rong Li

2008-01-01

453

LARVAL FISH DISTRIBUTIONS IN SOUTHWESTERN LAKE ERIE NEAR THE MONROE POWER PLANT  

EPA Science Inventory

This paper presents and discusses studies of larval fish distribution near a large power plant on western Lake Erie using methods that attempt to account for the confounding effect of environmental variation on technique effectiveness. Distributions in the coastal zone were sampl...

454

Distributed control for automatic fire detection and monitoring system for a nuclear power plant  

Microsoft Academic Search

The design of a three-level distributed control system for fire detection and monitoring in a nuclear power plant is presented. The system design fully satisfies the requirements of the US NRC Regulatory Guides and the provisions of the latest National Fire Codes. The three levels of distributed control are: (1) Local Fire Detection Control Panel, (2) Main Control Room Fire

C. N. Bagchi; A. K. Chakraberti

1984-01-01

455

Development of Power Supply System with Distributed Generators using Parallel Processing Method  

NASA Astrophysics Data System (ADS)

This paper describes a novel power system which consists of distributed energy resources (DER) with a static switch at the point of common coupling. Usage of the static switch with a parallel processing control is a new application of line interactive type uninterruptible power supply (UPS). In recent years, various ways of design, operation, and control methods have been studied in order to find more effective ways to utilize renewable energy and to reduce impact for environment. One of features of a proposed power system can interconnect to existing utility grid without interruption. Electrical power distribution to the loads by the power system can be continued between the states of interconnection and isolate operation seamlessly. The novel power system has other benefits such as more efficiency, demand site management, easy to control power system inside, improvement of reliability for power distribution, the minimum requirement of protection relays for grid interconnection. The proposed power system has been operated with the actual loads of 20kW in the campus of the Aichi Institute of Technology since 2007.

Hirose, Kenichi; Takeda, Takashi; Okui, Yoshiaki; Yukita, Kazuto; Goto, Yasuyuki; Ichiyanagi, Katsuhiro; Matsumura, Toshiro

456

A Variable Directional Coupler for an Alternate ILC High-Power RF Distribution Scheme  

SciTech Connect

We describe the design and functionality of an RF directional coupler for which the power division between the output ports is mechanically variable. In an alternate power distribution scheme for the ILC, power is delivered to cavities in pairs, through hybrids. Four pairs, or eight cavities, are fed from one waveguide feed, from which one fourth, one third, and one half of the power is coupled out at consecutive directional couplers. Three such feeds are powered by a single 10 MW klystron. Experience suggests that cavities considered useable will display some variation in the operational accelerating gradient they can sustain. With fixed distribution, the klystron power must be kept below the level at which the weakest cavity out of 24 receives its power limit. This problem can be solved by installing variable attenuators, but that means wasting precious power. With adjustable coupling, distribution can be optimized for more efficient use both of available power and of the accelerating cavities. This novel device, feeding cavities paired by similar performance, can provide such benefit to the ILC.

Nantista, Christopher D.; Adophsen, Chris; /SLAC

2007-03-16

457

Power flow analysis for DC voltage droop controlled DC microgrids  

E-print Network

of "smart grid". According to the source type, microgrids can be divided into AC microgrids and DC microgrids. To cope with inherent problems related to AC microgrids, such as the need for synchronization of the distributed generators, the inrush currents due to transformers, reactive-power flow, harmonic currents

Chaudhary, Sanjay

458

Three AC\\/AC single phase voltage regulators analysed in a comparative way  

Microsoft Academic Search

This paper presents a comparative analysis of three AC\\/AC single-phase voltage regulators. Two of these regulators are active series filters, one being the dual of the other. These AC\\/AC series regulators are compared with the boost\\/inverter converter, the most common topology employed as AC\\/AC single-phase regulator in electronics equipment. The boost\\/inverter regulator has the advantage of input unity power factor.

J. C. de Oliveira; V. J. Farias; Luiz Carlos de Freitas

2001-01-01

459

On-line test of power distribution prediction system for boiling water reactors  

SciTech Connect

A power distribution prediction system for boiling water reactors has been developed and its on-line performance test has proceeded at an operating commercial reactor. This system predicts the power distribution or thermal margin in advance of control rod operations and core flow rate change. This system consists of an on-line computer system, an operator's console with a color cathode-ray tube, and plant data input devices. The main functions of this system are present power distribution monitoring, power distribution prediction, and power-up trajectory prediction. The calculation method is based on a simplified nuclear thermal-hydraulic calculation, which is combined with a method of model identification to the actual reactor core state. It has been ascertained by the on-line test that the predicted power distribution (readings of traversing in-core probe) agrees with the measured data within 6% root-mean-square. The computing time required for one prediction calculation step is less than or equal to 1.5 min by an HIDIC-80 on-line computer.

Nishizawa, Y.; Kiguchi, T.; Kobayashi, S.; Takumi, K.; Tanaka, H.; Tsutsumi, R.; Yokomi, M.

1982-07-01

460

Stress measurement with fiber optical sensors using modal power distribution: A comparison of power-meter and CCD camera techniques  

NASA Astrophysics Data System (ADS)

In this paper, we investigate modal power distribution (MPD)-based fiber optical stress measurement, and compare power-meter and CCD camera-based techniques. We also consider the sensor location selection problem in the power-meter-based approach, which consists of placing sensor(s) in different locations. We first show that power-meter measurement data can be estimated from CCD camera images by using image processing techniques. As a second result, we also show that the lengthy process of placing sensors in different locations in search of best sensor placement can be totally avoided. We formulate this as a max-min problem, and propose a computer-based solution.

Efendioglu, H. S.; Esen, M. E.; Toker, O.; Fidanboylu, K.

2010-04-01

461

Impact of Distributed Wind on Bulk Power System Operations in ISO-NE: Preprint  

SciTech Connect

The work presented in this paper aims to study the impact of a range of penetration levels of distributed wind on the operation of the electric power system at the transmission level. This paper presents a case study on the power system in Independent System Operator New England. It is analyzed using PLEXOS, a commercial power system simulation tool. The results show that increasing the integration of distributed wind reduces total variable electricity generation costs, coal- and gas-fired electricity generation, electricity imports, and CO2 emissions, and increases wind curtailment. The variability and uncertainty of wind power also increases the start-up and shutdown costs and ramping of most conventional power plants.

Brancucci Martinez-Anido, C.; Hodge, B. M.; Palchak, D.; Miettinen, J.

2014-09-01

462

Distribution of power output during cycling: impact and mechanisms.  

PubMed

We aim to summarise the impact and mechanisms of work-rate pacing during individual cycling time trials (TTs). Unlike time-to-exhaustion tests, a TT provides an externally valid model for examining how an initial work rate is chosen and maintained by an athlete during self-selected exercise. The selection and distribution of work rate is one of many factors that influence cycling speed. Mathematical models are available to predict the impact of factors such as gradient and wind velocity on cycling speed, but only a few researchers have examined the inter-relationships between these factors and work-rate distribution within a TT. When environmental conditions are relatively stable (e.g. in a velodrome) and the TT is >10 minutes, then an even distribution of work rate is optimal. For a shorter TT (< or = 10 minutes), work rate should be increased during the starting effort because this proportion of total race time is significant. For a very short TT (< or = 2 minutes), the starting effort should be maximal, since the time saved during the starting phase is predicted to outweigh any time lost during the final metres because of fatigue. A similar 'time saving' rationale underpins the advice that work rate should vary in parallel with any changes in gradient or wind speed during a road TT. Increasing work rate in headwind and uphill sections, and vice versa, decreases the variability in speed and, therefore, the total race time. It seems that even experienced cyclists naturally select a supraoptimal work rate at the start of a longer TT. Whether such a start can be 'blunted' through coaching or the monitoring of psychophysiological variables is unknown. Similarly, the extent to which cyclists can vary and monitor work rate during a TT is unclear. There is evidence that sub-elite cyclists can vary work rate by +/-5% the average for a TT lasting 25-60 minutes, but such variability might be difficult with high-performance cyclists whose average work rate during a TT is already extremely high (>350 watts). During a TT, pacing strategy is regulated in a complex anticipatory system that monitors afferent feedback from various physiological systems, and then regulates the work rate so that potentially limiting changes do not occur before the endpoint of exercise is reached. It is critical that the endpoint of exercise is known by the cyclist so that adjustments to exercise work rate can be made within the context of an estimated finish time. Pacing strategies are thus the consequence of complex regulation and serve a dual role: they are both the result of homeostatic regulation by the brain, as well as being the means by which such regulation is achieved. The pacing strategy 'algorithm' is sited in the brain and would need afferent input from interoceptors, such as heart rate and respiratory rate, as well as exteroceptors providing information on local environmental conditions. Such inputs have been shown to induce activity in the thalamus, hypothalamus and the parietal somatosensory cortex. Knowledge of time, modulated by the cerebellum, basal ganglia and primary somatosensory cortex, would also input to the pacing algorithm as would information stored in memory about previous similar exercise bouts. How all this information is assimilated by the different regions of the brain is not known at present. PMID:17645369

Atkinson, Greg; Peacock, Oliver; St Clair Gibson, Alan; Tucker, Ross

2007-01-01

463

Power quality enhancement at distribution level utilizing the unified power quality conditioner (UPQC)  

NASA Astrophysics Data System (ADS)

The present doctoral work is based on the philosophy of optimal utilization of the available resources in a most effective and efficient way to improve the product efficiency and to reduce the overall cost. This work proposes a novel control philosophy termed as power angle control (PAC), in which both the series and shunt inverters share the load reactive power in co-ordination with each other without affecting the basic UPQC compensation capabilities. This eventually results in a better utilization of the series inverter, reduction in the shunt inverter rating to some extent and ultimately in the reduction of the overall cost of UPQC. Moreover, in this thesis work several other control approaches are also proposed, such as, unit vector template generation, quadrature voltage injection, generalized single-phase p-q theory and novel current unbalance compensation approach. All the developed concepts are successfully validated through digital simulation as well as extensive experimental investigations. Keywords. power quality, active power filter, unified power quality conditioner, reactive power compensation, harmonics compensation.

Khadkikar, Vinod

464

Power distribution in the snowflake divertor in TCV  

NASA Astrophysics Data System (ADS)

TCV experiments demonstrate the basic power exhaust properties of the snowflake (SF) plus and SF minus divertor configurations by measuring the heat fluxes at each of their four divertor legs. The measurements indicate an enhanced transport into the private flux region and a reduction of peak heat fluxes compared to a similar single null configuration. There are indications that this enhanced transport cannot be explained by the modified field line geometry alone and likely requires an additional or enhanced cross-field transport channel. The measurements, however, do not show a broadening of the scrape-off layer (SOL) and, hence, no increased cross-field transport in the common flux region. The observations are consistent with the spatial limitation of several characteristic SF properties, such as a low poloidal magnetic field in the divertor region and a long connection length to the inner part of the SOL closest to the separatrix. Although this limitation is typical in a medium sized tokamak like TCV, it does not apply to significantly larger devices where the SF properties are enhanced across the entire expected extent of the SOL.

Reimerdes, H.; Canal, G. P.; Duval, B. P.; Labit, B.; Lunt, T.; Vijvers, W. A. J.; Coda, S.; De Temmerman, G.; Morgan, T. W.; Nespoli, F.; Tal, B.; the TCV Team

2013-12-01

465

Low-cost distributed solar-thermal-electric power generation  

NASA Astrophysics Data System (ADS)

Due to their high relative cost, solar electric energy systems have yet to be exploited on a widespread basis. It is believed in the energy community that a technology similar to photovoltaic (PV), but offered at about $1/W would lead to widespread deployment at residential and commercial sites. This paper addresses the investigation and feasibility study of a low-cost solar thermal electricity generation technology, suitable for distributed deployment. Specifically, we discuss a system based on nonimaging solar concentrators, integrated with free-piston Stirling engine devices incorporating integrated electric generation. We target concentrator-collector operation at moderate temperatures, in the range of 125°C to 150°C. This temperature is consistent with use of optical concentrators with concentration ratios on the order of 1-2. These low ratio concentrators admit wide angles of radiation acceptance and are thus compatible with no diurnal tracking, and no or only a few seasonal adjustments. Thus, costs and reliability hazards associated with tracking hardware systems are avoided. Further, we note that in the intended application, there is no shortage of incident solar energy, but rather it is the capital cost of the solar-electric system that is most precious. Thus, we outline a strategy for exploiting solar resources in a cost constrained manner. The paper outlines design issues, and a specific design for an appropriately dimensioned free-piston Stirling engine. Only standard low-cost materials and manufacturing methods are required to realize such a machine.

Der Minassians, Artin; Aschenbach, Konrad H.; Sanders, Seth R.

2004-01-01

466

Power quality improvement based on novel power electronic transformer  

Microsoft Academic Search

This paper presents a novel topology of power electronic transformer. In the design process, the AC\\/DC, DC\\/AC, AC\\/AC converters and high frequency transformer have been used. One matrix converter operates as AC\\/AC converter in power electronic transformer. The proposed power electronic transformer performs typical functions and has advantages such as power factor correction, voltage sag and swell elimination, voltage flicker

M. R. Banaei; E. Salary

2011-01-01

467

Recognizing animal-caused faults in power distribution systems using artificial neural networks  

SciTech Connect

Faults are likely to occur in most power distribution systems. If the causes of the faults are known, specific action can be taken to eliminate the fault sources as soon as possible to avoid unnecessary costs, such as power system down-time cost, that are caused by failing to identify the fault sources. However, experts that can accurately recognize the causes of distribution faults are scarce and the knowledge about the nature of these faults is easily transferable from person to person. Therefore, artificial neural networks are used in this paper to recognize the causes of faults in power distribution systems, based on fault currents information collected for each outage. Actual field data collected by Duke Power Company are used in this paper. The methodology and implementation of artificial neural networks and fuzzy logic for the identification of animal-caused distribution faults will be presented. Satisfactory results have been obtained, and the developed methodology can be easily generalized and used to identify other causes of faults in power distribution systems.

Chow, Mo Yuen; Yee, S.O. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Electrical and Computer Engineering); Taylor, L.S. (Duke Power Co., Charlotte, NC (United States). Distribution Engineering)

1993-07-01

468

Augmentation of the space station module power management and distribution breadboard  

NASA Technical Reports Server (NTRS)

The space station module power management and distribution (SSM/PMAD) breadboard models power distribution and management, including scheduling, load prioritization, and a fault detection, identification, and recovery (FDIR) system within a Space Station Freedom habitation or laboratory module. This 120 VDC system is capable of distributing up to 30 kW of power among more than 25 loads. In addition to the power distribution hardware, the system includes computer control through a hierarchy of processes. The lowest level consists of fast, simple (from a computing standpoint) switchgear that is capable of quickly safing the system. At the next level are local load center processors, (LLP's) which execute load scheduling, perform redundant switching, and shed loads which use more than scheduled power. Above the LLP's are three cooperating artificial intelligence (AI) systems which manage load prioritizations, load scheduling, load shedding, and fault recovery and management. Recent upgrades to hardware and modifications to software at both the LLP and AI system levels promise a drastic increase in speed, a significant increase in functionality and reliability, and potential for further examination of advanced automation techniques. The background, SSM/PMAD, interface to the Lewis Research Center test bed, the large autonomous spacecraft electrical power system, and future plans are discussed.

Walls, Bryan; Hall, David K.; Lollar, Louis F.

1991-01-01

469

Intelligent Monitoring System With High Temperature Distributed Fiberoptic Sensor For Power Plant Combustion Processes  

SciTech Connect

The objective of the proposed work is to develop an intelligent distributed fiber optical sensor system for real-time monitoring of high temperature in a boiler furnace in power plants. Of particular interest is the estimation of spatial and temporal distributions of high temperatures within a boiler furnace, which will be essential in assessing and controlling the mechanisms that form and remove pollutants at the source, such as NOx. The basic approach in developing the proposed sensor system is three fold: (1) development of high temperature distributed fiber optical sensor capable of measuring temperatures greater than 2000 C degree with spatial resolution of less than 1 cm; (2) development of distributed parameter system (DPS) models to map the three-dimensional (3D) temperature distribution for the furnace; and (3) development of an intelligent monitoring system for real-time monitoring of the 3D boiler temperature distribution. Under Task 1, we set up a dedicated high power, ultrafast laser system for fabricating in-fiber gratings in harsh environment optical fibers, successfully fabricated gratings in single crystal sapphire fibers by the high power laser system, and developed highly sensitive long period gratings (lpg) by electric arc. Under Task 2, relevant mathematical modeling studies of NOx formation in practical combustors. Studies show that in boiler systems with no swirl, the distributed temperature sensor may provide information sufficient to predict trends of NOx at the boiler exit. Under Task 3, we investigate a mathematical approach to extrapolation of the temperature distribution within a power plant boiler facility, using a combination of a modified neural network architecture and semigroup theory. The 3D temperature data is furnished by the Penn State Energy Institute using FLUENT. Given a set of empirical data with no analytic expression, we first develop an analytic description and then extend that model along a single axis. Extrapolation capability was demonstrated for estimating enthalpy in a power plant.

Kwang Y. Lee; Stuart S. Yin; Andre Boheman

2005-12-26

470

Space station electrical power distribution analysis using a load flow approach  

NASA Technical Reports Server (NTRS)

The space station's electrical power system will evolve and grow in a manner much similar to the present terrestrial electrical power system utilities. The initial baseline reference configuration will contain more than 50 nodes or busses, inverters, transformers, overcurrent protection devices, distribution lines, solar arrays, and/or solar dynamic power generating sources. The system is designed to manage and distribute 75 KW of power single phase or three phase at 20 KHz, and grow to a level of 300 KW steady state, and must be capable of operating at a peak of 450 KW for 5 to 10 min. In order to plan far into the future and keep pace with load growth, a load flow power system analysis approach must be developed and utilized. This method is a well known energy assessment and management tool that is widely used throughout the Electrical Power Utility Industry. The results of a comprehensive evaluation and assessment of an Electrical Distribution System Analysis Program (EDSA) is discussed. Its potential use as an analysis and design tool for the 20 KHz space station electrical power system is addressed.

Emanuel, Ervin M.

1987-01-01

471

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

SciTech Connect

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.

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

2011-07-09

472

An Encoding Technique for Multiobjective Evolutionary Algorithms Applied to Power Distribution System Reconfiguration  

PubMed Central

Network reconfiguration is an alternative to reduce power losses and optimize the operation of power distribution systems. In this paper, an encoding scheme for evolutionary algorithms is proposed in order to search efficiently for the Pareto-optimal solutions during the reconfiguration of power distribution systems considering multiobjective optimization. The encoding scheme is based on the edge window decoder (EWD) technique, which was embedded in the Strength Pareto Evolutionary Algorithm 2 (SPEA2) and the Nondominated Sorting Genetic Algorithm II (NSGA-II). The effectiveness of the encoding scheme was proved by solving a test problem for which the true Pareto-optimal solutions are known in advance. In order to prove the practicability of the encoding scheme, a real distribution system was used to find the near Pareto-optimal solutions for different objective functions to optimize. PMID:25401144

Guardado, J. L.; Rivas-Davalos, F.; Torres, J.; Maximov, S.; Melgoza, E.

2014-01-01

473

Decoupling Capacitors for Power Distribution Systems with Multiple Power Supply Voltages  

E-print Network

target timing constraints) while permitting modules along the non-critical paths to use a lower voltage by the Semiconductor Research Corporation under Contract No. 2003-TJ-1068, the DARPA/ITO under AFRL Contract F29601 a small fraction of the power supply voltage (about 5%) is permitted as ripple voltage (noise), a target

Friedman, Eby G.

474

Ion distribution and electronic stopping power for Au ions in silicon carbide  

SciTech Connect

Accurate knowledge of ion distribution and electronic stopping power for heavy ions in light targets is highly desired due to the large errors in prediction by the widely used Stopping and Range of Ions in Matter (SRIM) code. In this study, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) are used as complementary techniques to determine the distribution of Au ions in SiC with energies from 700 keV to 15 MeV. In addition, a single ion technique with an improved data analysis procedure is applied to measure the electronic stopping power for Au ions in SiC with energies up to 70 keV/nucleon. Large overestimation of the electronic stopping power is found by SRIM prediction in the low energy regime up to 50 keV/nucleon. The stopping power data and the ion ranges are crosschecked with each other and a good agreement is achieved.

Jin, Ke [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL; Xue, Haizhou [University of Tennessee, Knoxville (UTK); Zhu, Zihua [Pacific Northwest National Laboratory (PNNL); Weber, William J [ORNL

2013-01-01

475

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

SciTech Connect

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.

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

2012-08-20

476

Advanced electrical power, distribution and control for the Space Transportation System  

NASA Technical Reports Server (NTRS)

High frequency power distribution and management is a technology ready state of development. As such, a system employs the fewest power conversion steps, and employs zero current switching for those steps. It results in the most efficiency, and lowest total parts system count when equivalent systems are compared. The operating voltage and frequency are application specific trade off parameters. However, a 20 kHz Hertz system is suitable for wide range systems.

Hansen, Irving G.; Brandhorst, Henry W., Jr.

1990-01-01

477

The research of Power Electronic Transformer (PET) in Smart distribution network  

Microsoft Academic Search

The transformers have been widely used in traditional power system, the primary functions of which are voltage-transformation, isolation and energy-transfer. Now with the development of Smart-Grid, power system requires an increasing penetration of the renewable energy resources and other distributed generations around loads, and an active role for DSOs in controlling the network stability, optimizing central and security. Owing to

Zhibing Wang; Kunshan Yu

2010-01-01

478

Intensity and absorbed-power distribution in a cylindrical solar-pumped dye laser  

NASA Technical Reports Server (NTRS)

The internal intensity and absorbed-power distribution of a simplified hypothetical dye laser of cylindrical geometry is calculated. Total absorbed power is also calculated and compared with laboratory measurements of lasing-threshold energy deposition in a dye cell to determine the suitability of solar radiation as a pump source or, alternatively, what modifications, if any, are necessary to the hypothetical system for solar pumping.

Williams, M. D.

1984-01-01

479

A power law distribution in patients’ lengths of stay in hospital  

NASA Astrophysics Data System (ADS)

The distribution of patients’ lengths of stay in English hospitals is measured by using routinely collected data from 11 years. It is found to be well approximated by a power law distribution spanning over more than three decades. To explain this observation, a theoretical resource allocation model is presented. It is based on iterative long-term scheduling of hospital beds, and its main assumption is that future beds are allocated preferentially. This represents a situation where different parts of the health care system compete for resources, with bargaining powers proportional to current resource levels.

Hellervik, A.; Rodgers, G. J.

2007-06-01

480

Power-like corrections and the determination of the gluon distribution  

E-print Network

Power-suppressed corrections to parton evolution may affect the theoretical accuracy of current determinations of parton distributions. We study the role of multigluon-exchange terms in the extraction of the gluon distribution for the Large Hadron Collider (LHC). Working in the high-energy approximation, we analyze multi-gluon contributions in powers of 1/Q^2. We find a moderate, negative correction to the structure function's derivative d F_2 / d \\ln Q^2, characterized by a slow fall-off in the region of low to medium Q^2 relevant for determinations of the gluon at small momentum fractions.

F. Hautmann

2006-10-06

481

Optimum operating strategies of future electric power distribution systems with various load control alternatives  

SciTech Connect

An electric power distribution system model was developed to determine the best operating strategies for future power distribution systems with single or multiple objectives. Load control alternatives such as storage devices, dispersed generators and cogenerators, load curtailment, and time of day pricing were included in the model. Then, a digital computer program (called OLCP for Optimal Load Control Program) was developed and used to determine optimum operating strategies for multiple objectives as well as a single objective. Finally, a number of sample runs were conducted to demonstrate the various capabilities of the model.

Muslu, M.

1986-01-01

482

On the application of a machine learning technique to fault diagnosis of power distribution lines  

SciTech Connect

This paper presents one method for fault diagnosis of power distribution lines by using a decision tree. The conventional method, using a decision tree, applies only to discrete attribute values. To apply it to fault diagnosis of power distribution lines, in practice it must be revised in order to treat attributes whose values range over certain widths. This is because the sensor value or attribute value varies owing to the resistance of the fault point or is influenced by noise. The proposed method is useful when the attribute value has such a property, and it takes into consideration the cost of acquiring the information and the probability of the occurrence of a fault.

Togami, Masato [Nagoya MFG (Japan)] [Nagoya MFG (Japan); Abe, Norihiro [Kyushu Inst. of Tech., Iizuka (Japan)] [Kyushu Inst. of Tech., Iizuka (Japan); Kitahashi, T. [Osaka Univ., Ibaraki (Japan)] [Osaka Univ., Ibaraki (Japan); Ogawa, Harunao [Togami Electric, Saga (Japan)] [Togami Electric, Saga (Japan)

1995-10-01

483

Power distributions in fresh and depleted LEU and HEU cores of the MITR reactor.  

SciTech Connect

The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. It delivers a neutron flux comparable to current LWR power reactors in a compact 6 MW core using Highly Enriched Uranium (HEU) fuel. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context, most research and test reactors both domestic and international have started a program of conversion to the use of Low Enriched Uranium (LEU) fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (UMo) is expected to allow the conversion of U.S. domestic high performance reactors like the MITR-II reactor. Toward this goal, core geometry and power distributions are presented. Distributions of power are calculated for LEU cores depleted with MCODE using an MCNP5 Monte Carlo model. The MCNP5 HEU and LEU MITR models were previously compared to experimental benchmark data for the MITR-II. This same model was used with a finer spatial depletion in order to generate power distributions for the LEU cores. The objective of this work is to generate and characterize a series of fresh and depleted core peak power distributions, and provide a thermal hydraulic evaluation of the geometry which should be considered for subsequent thermal hydraulic safety analyses.

Wilson, E.H.; Horelik, N.E.; Dunn, F.E.; Newton, T.H., Jr.; Hu, L.; Stevens, J.G. (Nuclear Engineering Division); (2MIT Nuclear Reactor Laboratory and Nuclear Science and Engineering Department)

2012-04-04

484

Examination on Temperature Distribution of a Pyramidal EM-wave Absorber Under High Power Injection  

Microsoft Academic Search

In this research, temperature distribution of a pyramidal EM-absorber under high power injection is computed by a coupled method called FDTD-SIMPLE-MR method. In this method, both electromagnetic field and all the heat transmission phenomena such as heat transportation, heat transfer by air convention and heat radiation can be calculated. Moreover, temperature distribution of a pyramidal EM-absorber is examined experimentally by

Tetsuhiro Sasagawa; O. Hashimoto; S. Watanabe; T. Saito; H. Kurihara

2007-01-01

485

Large-scale distributed computational fluid dynamics on the information power grid using Globus  

Microsoft Academic Search

This paper describes an experiment in which a large-scale scientific application developed 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

S. Barnard; R. Biswas; S. Saini; R. Van der Wijngaart; M. Yarrow; L. Zechtzer; I. Foster; O. Larsson

1999-01-01

486

Stopping power of extended cluster and ion charge distributions in an arbitrarily degenerate electron fluid  

Microsoft Academic Search

The stopping power of an extended charge distribution at any velocity by a free-electron gas is calculated in the random-phase approximation at any degeneracy. Asymptotic expressions are given in the low- and high-velocity range for any charge distribution with spherical symmetry. We pay attention to the determination of the critical distances of pointlike behavior for an extended charge and uncorrelated

A. Bret; C. Deutsch

1993-01-01

487

Co-modeling, Experimental Verification, and Analysis of Chip-Package Hierarchical Power Distribution Network  

Microsoft Academic Search

In this paper, we present and verify a new chip-package co-modeling and simulation approach for a low-noise chip-package hierarchical power distribution network (PDN) design. It is based on a hierarchical modeling to combine distributed circuit models at both chip-level PDN and package-level PDN. In particular, it includes all on- and off-chip parasitic circuit elements in the hierarchical PDN with a

Hyungsoo Kim; Jun So Pak; Changwook Yoon; Kyoungchoul Koo; Joungho Kim

2008-01-01

488

Fully integrated distributed power amplifier in CMOS technology, optimized for UWB transmitters  

Microsoft Academic Search

A power amplifier (PA) using the distributed amplifier technique for the ultra wideband (UWB) standard is presented. The amplifier is fabricated in a standard 0.13 ?m CMOS technology and comes with on-chip biasing circuitry and a non-distributed input stage. Measurement results are given for a chip-on-board module to take any influence of product assembly into account. It achieves a transmission

Christian Grewing; Kay Winterberg; Stefan van Waasen; Martin Friedrich; Giuseppe Li Puma; A. Wiesbauer; C. Sandner

2004-01-01

489

Optimized Design of Distributed Power Systems for High Efficiency, High Power Density and Low EMI Noise  

Microsoft Academic Search

This paper first discussed the EMI issues and solutions for boost PFC converters. The parasitic cancellation technique is then introduced to improve EMI filter's high frequency performance. A two-stage PFC topology is introduced to improve the power density of PFC. LLC topology is recommended for front-end DC\\/DC converters due to it high efficiency. For onboard DC\\/DC converters, one-stage approach is

Fred C. Lee; Shuo Wang; Ming Xu; Bing Lu; Chuanyun Wang; Pengju Kong

2006-01-01

490

Influence of solid state electrical distribution on aircraft power generation solid state power controller compatibility  

Microsoft Academic Search

A compatibility study and engineering test evaluation on solid state power controllers (SSPC) was conducted to provide documentation and technical information to the Air Force of the factors needed for the technical decision of compatibility of SSPC on the B-1 air vehicle. Part I of this report documents the Baseline, Analysis, Weight-Volume NA-72-229-1. The Supplement to the report contains a

S. Dawson; J. E. Phillips; R. Urdanivia

1974-01-01

491

Space Station Power System issues  

NASA Technical Reports Server (NTRS)

A number of attractive options are available for the Space Station Power System. These include a photovoltaic system or solar dynamic system for power generation, batteries or fuel cells for energy storage and ac or dc for power management and distribution. These options are being explored during the present preliminary design and definition phase of the Space Station Program. Final selections are presently targeted for January 1986.

Forestieri, A. F.

1985-01-01

492

Thermal power systems, point-focusing distributed receiver technology project. Volume 2: Detailed report  

NASA Technical Reports Server (NTRS)

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver technology is the goal of this Project. The energy thus produced must be economically competitive with other sources. The Project supports the industrial development of technology and hardware for extracting energy from solar power to achieve the stated goal. Present studies are working to concentrate the solar energy through mirrors or lenses, to a working fluid or gas, and through a power converter change to an energy source useful to man. Rankine-cycle and Brayton-cycle engines are currently being developed as the most promising energy converters for our near future needs.

Lucas, J.

1979-01-01

493

Three dimensional microwave heating power distribution in an electron cyclotron resonance processing plasma  

SciTech Connect

The authors are currently investigating the mechanisms of microwave power absorption in an ECR plasma. Relative microwave power measurements are made in the vicinity of the quartz window where 2.45 GHz heating power enters the plasma chamber. One dimensional measurements along the axis have been reported in which Faraday rotation of the incident electric field has been observed. Here, 3-D profiles of the microwave heating power distribution will be presented, as well as profiles of each electric field component. The purpose of this study is to explain how microwave power is absorbed in the plasma, especially the electric field component that is not resonant with electron cyclotron motion. They also try to clarify the transition between the low and high density mode. The low mode is characterized by an E field configuration with peaks and nodes throughout the plasma chamber. This is like a standing wave in a circular cavity with a weak plasma dielectric. In the high mode there is no detectable power beyond the resonance zone. The microwave field intensity is greatest in front of the waveguide opening, 2 to 5 cm from the quartz plate. Finally, the 3-D power distribution will be used in a computer simulation of this ECR reactor to accurately model the electron heat source.

Douglass, S.R.; Eddy, C.; Weber, B.V. [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.

1996-12-31

494

Power Hardware-in-the-Loop (PHIL) Testing Facility for Distributed Energy Storage (Poster)  

SciTech Connect

The growing deployment of distributed, variable generation and evolving end-user load profiles presents a unique set of challenges to grid operators responsible for providing reliable and high quality electrical service. Mass deployment of distributed energy storage systems (DESS) has the potential to solve many of the associated integration issues while offering reliability and energy security benefits other solutions cannot. However, tools to develop, optimize, and validate DESS control strategies and hardware are in short supply. To fill this gap, NREL has constructed a power hardware-in-the-loop (PHIL) test facility that connects DESS, grid simulator, and load bank hardware to a distribution feeder simulation.

Neubauer.J.; Lundstrom, B.; Simpson, M.; Pratt, A.

2014-06-01

495

GEOMAGNETIC STORM RISKS TO ELECTRIC POWER DISTRIBUTION AND SUPPLY SYSTEMS AT MIDLATITUDE LOCATIONS AND THEIR VULNERABILITY FROM SPACE WEATHER  

Microsoft Academic Search

The effects of space weather on power distribution and supply systems are briefly described. Results of studies on the impact of geomagnetic storms of various strengths on electric power supply systems in Azerbaijan (mid latitudes) are provided. Perspectives of study of space weather effects on operational conditions of the regional electric power industry as well vulnerability of electric power systems

E. S. Babayev; A. M. Hashimov; N. A. Yusifbeyli

496

In Proceedings IEEE International Parallel and Distributed Processing Syposium (IPDPS) 2013 Time-Power Tradeoffs for Sorting on a  

E-print Network

constraints on their layout. In an abstract model, we show that a pyramidal layout and a new power simultaneously powered decreases. Previous algorithms assumed fully powered systems, hence pyramid sortingIn Proceedings IEEE International Parallel and Distributed Processing Syposium (IPDPS) 2013 Time-Power

Stout, Quentin F.

497

Spatial and temporal distributions of U.S. winds and wind power at 80 m derived from measurements  

E-print Network

Spatial and temporal distributions of U.S. winds and wind power at 80 m derived from measurements 2002; published 13 May 2003. [1] This is a study to quantify U.S. wind power at 80 m (the hub height methods previously used to obtain elevated data for U.S. wind power maps, a logarithmic law and a power

498

Social Power as an Exchangeable Resource for Distributed Multi-Agent Systems Department of Computer Engineering and  

E-print Network

Social Power as an Exchangeable Resource for Distributed Multi-Agent Systems Don Hayes Department and decay are explored. KEYWORDS: Multi-Agent Systems, Social Power, Power, Tokens, Fault-Tolerance 1 of agents increases [1]. Ben- Ami and Shehory do not address the concept of social power. Techniques have

Hexmoor, Henry

499

Heterogeneity of Human Activity Levels Gives Rise to Power-Law Distribution in Online Social Networks  

NASA Astrophysics Data System (ADS)

It is well established that the distribution of social ties (degree) of an individual in a social network follows a power-law. How this heavy-tailed distribution arises in practice, however, has not been conclusively demonstrated. Mechanisms of ``preferential-attachment'' and optimization are often cited as the origin of heavy-tailed degree distributions. Our data indicate that there is a different cause for these phenomena. For different social networks we find an intrinsic relationship degree and activity (number of posts, edits etc): The degree distribution is entirely random except for its mean value which depends deterministically on the volume of the users' activity. This suggests that heavy-tailed degree distribution is a consequence of the intrinsic activity of users. More importantly, human activity deterministically affects the mean success at establishing links in a social network, and the specific degree of a given user is otherwise random following a ``maximum entropy attachment'' model.

Muchnik, Lev; Pei, Sen; Parra, Lucas; Reis, Saulo; Andrade, José., Jr.; Havlin, Shlomo; Makse, Hernan

2013-03-01

500

A distributed remote simulation system for electric power supply system of subway  

Microsoft Academic Search

In this paper we present an approach to build up a simulation system for power supply system of subway on the World Wide Web based on a distributed processing architecture. There are several advantages to this approach. First of all, users can employ this tool through a Web browser without any investment in maintenance of expensive hard- and software at

Zheng Yongping; Qian Qingquan

2000-01-01