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1

High Frequency AC Power Distribution Platforms  

Microsoft Academic Search

High Frequency AC (HFAC) power distribution system concerns the delivery of power at multi-kHz frequency via electric cables.\\u000a Early work on HFAC has demonstrated the many potential benefits of HFAC systems in terms of flexibility to meet loads at different\\u000a voltage levels, ease of electrical isolation using compact high frequency transformers, and the prospect of significant savings\\u000a in component count

Patrick Chi-Kwong Luk; Andy Seng Yim Ng

2

High-frequency AC power distribution in Space Station  

Microsoft Academic Search

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, low-frequency AC voltage from a solar dynamic generator into a regulated, 20-G kHz AC voltage for distribution among various loads. Operations of the components of the system such as driver inverter, DC

FU-SHENG TSAI; FRED C Y. LEE

1990-01-01

3

High-Frequency ac Power-Distribution System  

NASA Technical Reports Server (NTRS)

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

Hansen, Irving G.; Mildice, James

1987-01-01

4

Power flow control with Distributed Flexible AC Transmission System (D-FACTS) devices  

Microsoft Academic Search

Distributed Flexible AC Transmission System (D-FACTS) devices offer many potential benefits to power system operations. This paper illustrates the flexibility of control that is achievable with D-FACTS devices. The impact of installing D-FACTS devices is examined by studying the sensitivities of power system quantities such as voltage magnitude, voltage angle, bus power injections, line power flows, and real power losses

Katherine M. Rogers; Thomas J. Overbye

2009-01-01

5

Various Considerations for Estimating Steady-State Voltage Drop in Low Voltage AC Power Distribution Systems  

Microsoft Academic Search

This paper provides a simplified approach on various considerations to estimate the steady-state voltage drop in low voltage AC power distribution systems. Apart from other parameters, 'load center distance' is critical in most of the cases to determine realistically the voltage drop. This aspect is therefore covered in detail by developing equations to compute the load center distance for various

Shanmuga S. Pandian; A. Al-Saihati; A. Fattani; O. Al-Othman

2006-01-01

6

Two stage resonant inverter for AC distributed power supply-full control of output voltage magnitude and phase angle  

Microsoft Academic Search

Paralleling of multiple resonant inverters is necessary for AC distributed power supply system. However, the multiple module operation (MMO) requires tight regulation of the output voltage of both amplitude and phase angle. Voltage control mode (VCM) has effective control over the amplitude of the output only. Perturbation, component tolerance and other forms of uncertainties cause phase discrepancy in the output

Z. M. Ye; P. K. Jain; P. C. Sen

2004-01-01

7

Evaluating alternatives for integrating distributed DC generation with AC power systems  

Microsoft Academic Search

Distributed generation generally means on site electric power generation devices such as photovoltaics or fuel cells that are installed at the customer end of the electric power system. One complication is that the photovoltaic panel and the fuel cell generate direct current (DC) while the electric power system and thus existing end use equipment has been designed for alternating current

F. Wicks

2000-01-01

8

Modelling and simulation of controlled bi-directional power electronic converters in a DC energy distribution line with AC grid- and motor-side active filtering  

Microsoft Academic Search

The paper deals with the modelling and simulation of the bi-directional power flow through different type of power electronic converters connected to a DC-energy distribution line, which is supplied from the AC grid by means a square-wave rectifier with active current filtering at unity power factor. The DC line is supplying more vector controlled AC drives, like PWM voltage-source inverter-fed

Maria IMECS; Csaba SZABO; l. I. Incze

2007-01-01

9

AC versus DC distribution systems- Did we get it right?  

Microsoft Academic Search

We presently enjoy a predominantly ac electrical distribution system, the engineering basis for which was designed over 100 years ago. While ac distribution systems have served us well, we should periodically pause to assess what opportunities we have accepted or been denied by the overwhelming predominance of ac electrical power distribution systems. What opportunities could be obtained by engineering dc

Hammerstrom; Donald J

2007-01-01

10

Power electronics and ac drives  

NASA Astrophysics Data System (ADS)

An integrated treatment of technological advances in power electronics and ac drives is presented. The topics include: power semiconductor devices, ac machines, phase-controlled converters and cycloconverters, voltage-fed inverter drives, current-fed inverter drives, slip power-controlled drives, control of induction and synchronous machines, and microcomputer control. Both practical and theoretical aspects of the technology are addressed, and numerical examples are given.

Bose, B. K.

11

Optimized restoration of combined ac\\/dc shipboard power systems including distributed generation and islanding techniques  

Microsoft Academic Search

Reconfiguration involves changing the status (OFF\\/ON) of switches, and reconfiguration for restoration involves changing the switch status to maximize the supply to loads that are left unsupplied after fault removal. Shipboard Power Systems (SPS) need automated reconfiguration for restoration schemes to restore vital loads quickly and efficiently in order to improve fight-through and survivability capabilities. The restoration in this paper

Sarika Khushalani; Jignesh Solanki; Noel Schulz

2008-01-01

12

Online monitoring of the distributed lateral displacement in large AC power generators using a high spatial resolution Brillouin optical fiber sensor  

NASA Astrophysics Data System (ADS)

We report for the first time, to the best of our knowledge, online monitoring of the distributed lateral displacement in large AC power generators using high spatial resolution differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA). To perform the measurement of distributed lateral displacements with periods of only a few cm in large AC power generators, a 2 cm spatial resolution strain measurement is realized using the differential pulse pair of 8/8.2 ns in DPP-BOTDA, and then the lateral displacements are reconstructed according to the strain-displacement relation with the assumption of a sine shape function. Using different fiberglass ripple springs, two types of lateral displacement with periods of 3 and 3.25 cm are demonstrated, obtaining a maximum displacement of 0.43 mm with a measurement accuracy of ~ 40 µm. This provides the information on the stator coil tightness through online monitoring of the distributed lateral displacement caused by the fiberglass ripple springs, and ensures safe operating conditions for large AC power generators. In addition, the large number of sensing points associated with distributed optical fiber sensors make it economically and technically practical to monitor large numbers of key components in a generator without any interference from the large magnetic and electrical fields.

Dong, Yongkang; Bao, Xiaoyi; Chen, Liang

2011-11-01

13

AC versus DC distribution systems- Did we get it right?  

SciTech Connect

We presently enjoy a predominantly ac electrical distribution system, the engineering basis for which was designed over 100 years ago. While ac distribution systems have served us well, we should periodically pause to assess what opportunities we have accepted or been denied by the overwhelming predominance of ac electrical power distribution systems. What opportunities could be obtained by engineering dc distribution into at least portions of our present system? What advantages of the present ac distribution system should be recognized and protected? This paper will focus on distribution within premise and low-voltage distribution systems. Specifically, we will address the conversion efficiency costs of adopting various premise ac and dc distribution system topologies. According to a simple predictive model formulated in this paper, premise residential dc distribution will incur unfavorable total conversion efficiency compared with existing ac premise distribution. However, if a residence is supplied by a fuel cell or another dc generator, the total conversion efficiency within a residential dc distribution system could be similar to, or even better than, that for ac distribution.

Hammerstrom, Donald J.

2007-06-28

14

AC Versus DC Distribution SystemsDid We Get it Right?  

Microsoft Academic Search

We presently enjoy a predominantly AC electrical distribution system, the engineering basis for which was designed over 100 years ago. While AC distribution systems have served us well, we should periodically pause to assess what opportunities we have accepted or been denied by the overwhelming predominance of AC electrical power distribution systems. What opportunities could be obtained by engineering DC

Donald J. Hammerstrom

2007-01-01

15

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

16

Distributed energy resources in grid interactive AC microgrids  

Microsoft Academic Search

Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexibility and reliability, becomes an attractive candidate for the configuration of future electrical power system. This paper gives an overview of DER units in the grid interactive ac microgrid. The options in structures and

Xiongfei Wang; Josep M. Guerrero; Zhe Chen; Frede Blaabjerg

2010-01-01

17

A low frequency AC to high frequency AC inverter with build-in power factor correction and soft-switching  

Microsoft Academic Search

This paper presents a full bridge AC-AC inverter for high frequency power distribution system with power factor correction stage controlled by a unified controller. The proposed inverter has the following features: 1) load independent output voltage with constant frequency and very low total harmonic distortion (THD); 2) soft switching of the full bridge switches for a wide range of input

Wennan Guo; Praveen K. Jain

2004-01-01

18

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 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...

2010-04-01

19

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

20

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

E-print Network

to stages toward compact realization, increased high-power handling capability, and improving utility interface. Modern ac/ac power converter topologies with various control strategies have been introduced for the further improvements, such as matrix...

Kwak, Sangshin

2005-08-29

21

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

22

STATE OF CALIFORNIA DISTRIBUTED ENERGY STORAGE DX AC SYSTEMES ACCEPTANCE  

E-print Network

STATE OF CALIFORNIA DISTRIBUTED ENERGY STORAGE DX AC SYSTEMES ACCEPTANCE CEC-MECH-14A (Revised 08/09) CALIFORNIA ENERGY COMMISSION CERTIFICATE OF ACCEPTANCE MECH-14A NA7.5.13 Distributed Energy Storage DX AC DISTRIBUTED ENERGY STORAGE DX AC SYSTEMES ACCEPTANCE CEC-MECH-14A (Revised 08/09) CALIFORNIA ENERGY COMMISSION

23

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

24

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

25

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

26

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

27

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

28

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500...Devices § 880.5500 AC-powered patient lift. (a) Identification. An...or mobile, used to lift and transport patients in the horizontal or other...

2010-04-01

29

HERA-B ELECTRIC POWER Power Distribution  

E-print Network

Notstrom 1 x 25 16 16 Installed power (kVA) 38 x 16 row 1-4, 6 3 x 25 row 5 9 x 16 Room 100: HERAHERA-B ELECTRIC POWER Power Distribution: HV = Hauptverteilung (main distribution frame) UV alarm etc.) 400 A = 400 A * 380 V = 263 kW 1~ = 220 V; 3~ = 380 v Power cable = Emergency power cable

30

Stability enhancement of power system by controlling HVDC power flow through the same AC transmission line  

Microsoft Academic Search

HVDC power transmission employing power electronic device provides a wide range of control in power transmission. Remote generators are sometimes used to supply power to infinite bus through a single circuit long AC transmission line. The system may loose stability after the clearance of a fault if the pre-fault power transfer or the fault clearance time is high. Simultaneous AC-DC

K. P. Basu

2009-01-01

31

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

32

AC\\/DC\\/AC high voltage traction drives with quasi-zero reactive power demand  

Microsoft Academic Search

A novel AC\\/DC\\/AC conversion structure has been developed, referring to single-phase AC (25 kV\\/50 Hz) traction systems using induction motor drives. High-voltage converters delivering multilevel voltage waveforms with lower harmonic content have been employed on both the line side and the motor side. High-performance techniques have been studied for controlling the whole system, assuring a quasi-unitary power factor and a

Sandro Bertini; Tommaso Ghiara; Mario Marchesoni

1993-01-01

33

Monte Carlo simulation of AC\\/DC\\/AC power converter distortion  

Microsoft Academic Search

Probabilistic analyses of AC\\/DC\\/AC power converter harmonic and interharmonic distortion are performed by using the Monte Carlo simulation. Starting from previous experiences of some of the authors, an analytical and simplified conversion system model recently proposed is recalled and discussed. A new model of the control system is presented. Different tests considering both mechanical working condition variability and supplying voltage

Rosario Carbone; Daniele Castaldo; Francesco De Rosa; Roberto Langella; Alfkedo Testa

2001-01-01

34

Static power conditioner using GTO converters for AC electric railway  

Microsoft Academic Search

This paper proposes a static power conditioner (SPC) using self-commutated inverters in order to solve the problems of an AC electric railway. For compensating the voltage unbalance of a three-phase electric power system, the SPC controls the electric power in railway substations. Besides, for compensating the voltage drop in the feeding circuit, the SPC controls the reactive power in sectioning

Y. Mochinaga; Y. Hisamizu; M. Takeda; T. Miyashita; K. Hasuike

1993-01-01

35

A hybrid smart AC\\/DC power system  

Microsoft Academic Search

Recently, a smart grid has been attracted attention from the background of the introduction promotion of natural energy. At present, a smart grid based on AC grid has been proposed. However, no paper or article has been presented or published on a smart grid based on DC grid. This paper presents a AC\\/DC hybrid power system. The system has advantages

Kyohei Kurohane; Tomonobu Senjyu; Akie Uehara; Atsushi Yona; Toshihisa Funabashi; Chul-Hwan Kim

2010-01-01

36

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

37

Electric power processing, distribution and control for advanced aerospace vehicles.  

NASA Technical Reports Server (NTRS)

The results of a current study program to develop a rational basis for selection of power processing, distribution, and control configurations for future aerospace vehicles including the Space Station, Space Shuttle, and high-performance aircraft are presented. Within the constraints imposed by the characteristics of power generation subsystems and the load utilization equipment requirements, the power processing, distribution and control subsystem can be optimized by selection of the proper distribution voltage, frequency, and overload/fault protection method. It is shown that, for large space vehicles which rely on static energy conversion to provide electric power, high-voltage dc distribution (above 100 V dc) is preferable to conventional 28 V dc and 115 V ac distribution per MIL-STD-704A. High-voltage dc also has advantages over conventional constant frequency ac systems in many aircraft applications due to the elimination of speed control, wave shaping, and synchronization equipment.

Krausz, A.; Felch, J. L.

1972-01-01

38

Power factor control system for AC induction motors  

NASA Technical Reports Server (NTRS)

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

Nola, F. J. (inventor)

1977-01-01

39

A single phase high frequency AC microgrid with an unified power quality conditioner  

Microsoft Academic Search

This paper presents a high frequency AC-based microgrid as an interesting step towards integration of renewable energy sources in a distributed generation system. The successful implementation of an HFAC microgrid depends on the best utilization of the sources and the common bus, which can be accomplished using a unified power quality conditioner (UQPC). The UPQC can compensate for current and

J. M. Correa; S. Chakraborty; M. G. Simoes; F. A. Farret

2003-01-01

40

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

41

Power management and distribution technology  

NASA Technical Reports Server (NTRS)

Power management and distribution (PMAD) technology is discussed in the context of developing working systems for a piloted Mars nuclear electric propulsion (NEP) vehicle. The discussion is presented in vugraph form. The following topics are covered: applications and systems definitions; high performance components; the Civilian Space Technology Initiative (CSTI) high capacity power program; fiber optic sensors for power diagnostics; high temperature power electronics; 200 C baseplate electronics; high temperature component characterization; a high temperature coaxial transformer; and a silicon carbide mosfet.

Dickman, John Ellis

1993-01-01

42

Distributed Space Solar Power  

NASA Technical Reports Server (NTRS)

The objective was to assess the feasibility of safely collecting solar power at geostationary orbit and delivering it to earth. A strategy which could harness a small fraction of the millions of gigawatts of sunlight passing near earth could adequately supply the power needs of earth and those of space exploration far into the future. Light collected and enhanced both spatially and temporally in space and beamed to earth provides probably the only practical means of safe and efficient delivery of this space solar power to earth. In particular, we analyzed the feasibility of delivering power to sites on earth at a comparable intensity, after conversion to a usable form, to existing power needs. Two major obstacles in the delivery of space solar power to earth are safety and the development of a source suitable for space. We focused our approach on: (1) identifying system requirements and designing a strategy satisfying current eye and skin safety requirements; and (2) identifying a concept for a potential space-based source for producing the enhanced light.

Fork, Richard L.

2001-01-01

43

AC-DC-AC Power Converters with Novel Approach to Power Factor Correction in Three-Phase Systems  

Microsoft Academic Search

The main goal of this paper is to propose three new three-phase to three-phase ac-dc-ac converters, in which the input side is implemented with three-phase three-level PFC rectifier. This rectifier presents some advantages when compared to the two-level rectifier, i.e.: a) operation with high power level; b) reduced voltage harmonics while operating at lower frequency; and c) better quality in

E. C. dos Santos; E. R. C. da Silva; A. A. M. Bento

2009-01-01

44

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

45

ePOWER Seminar AC solar cells: A new breed of PV power generation  

E-print Network

ePOWER Seminar AC solar cells: A new breed of PV power generation Professor Faisal Khan Assistant will provide a guideline for solar cell designers to fabricate various discrete components in a power converter-junction solar cells. Prof. Khan is the founder of the Power Engineering and Automation Research Lab (PEARL

Abolmaesumi, Purang

46

MULTIFUNCTIONAL CAPABILITY OF A HIGH-VOLTAGE AC POWER CONDITIONER  

Microsoft Academic Search

Recent implementations of direct connected high-voltage ac power conditioners have focused on fundamental frequency power control, while other control objectives have not been exercised. This paper illustrates the multi-functional capability of a prototype high-voltage (11kV) conditioner and discusses the practicalities of building such a unit. Initial laboratory testing confirms that the unit can perform all four of the proposed functions,

Roger Brough; Shayne Crimp; Alister Gardiner

47

Building Block Converter Module for Universal (AC-DC, DC-AC, DC-DC) Fully Modular Power Conversion Architecture  

Microsoft Academic Search

This paper presents the configuration and control methods for a building block module suitable for application in a fully modular, AC-DC, DC-AC and DC-DC power conversion architecture, where the modules can be connected in any combination of series and parallel connections and support bidirectional power flow. The advantages of the proposed configuration, which is a combination of AC PWM full

Harish K. Krishnamurthy; Raja Ayyanar

2007-01-01

48

21 CFR 880.5510 - Non-AC-powered patient lift.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Non-AC-powered patient lift. 880.5510 Section 880.5510...Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or...

2010-04-01

49

Magnetic power inverter: AC voltage generation from DC magnetic fields  

NASA Astrophysics Data System (ADS)

We propose a method that allows power conversion from DC magnetic fields to AC electric voltages using domain wall (DW) motion in ferromagnetic nanowires. The device concept relies on spinmotive force, voltage generation due to magnetization dynamics. Sinusoidal modulation of the nanowire width introduces a periodic potential for a DW, the gradient of which exerts variable pressure on the traveling DW. This results in time variation of the DW precession frequency and the associated voltage. Using a one-dimensional model, we show that the frequency and amplitude of the AC outputs can be tuned by the DC magnetic fields and wire-design.

Ieda, Jun'ichi; Maekawa, Sadamichi

2012-12-01

50

Optimal active power flow incorporating power flow control needs in flexible AC transmission systems  

Microsoft Academic Search

This paper presents a new method to incorporate the power flow control needs of flexible AC transmission system (FACTS) in studying the optimal active power flow problem. The linearized (DC) network model is used in this paper. Three main types of FACTS devices, namely thyristor controlled series compensators (TCSC), thyristor controlled phase shifters (TCPS) and unified power flow controllers (UPFC),

S. Y. Ge; T. S. Chung

1999-01-01

51

A novel stability criterion of AC power system with constant power load  

Microsoft Academic Search

Power electronic converters in AC power system, such as the boost rectifier, behave as constant power loads (CPLs), which have negative impedance characteristics at the input terminals. And this might cause system instability. In small-signal sense, the stability of the system including the CPL is determined by the source output impedance and the load input impedance (admittance). As a result,

Zeng Liu; Jinjun Liu; Weihan Bao; Yalin Zhao; Fangcheng Liu

2012-01-01

52

Simulation based reliability evaluation of AC power supply system of Indian Nuclear Power Plant  

Microsoft Academic Search

Purpose – The purpose of this paper is to demonstrate the potential of simulation approach for performance evaluation in a complex environment with a case of application from Indian Nuclear Power Plant. Design\\/methodology\\/approach – In this work, stochastic simulation approach is applied to availability evaluation of AC Power supply system of Indian Nuclear Power Plant (INPP). In the presently followed

K. Durga Rao; H. S. Kushwaha; A. K. Verma; A. Srividya

2007-01-01

53

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

54

Numerical modeling of MgB2 conductors for high power AC transmission  

NASA Astrophysics Data System (ADS)

Cables made of MgB2 superconductors are currently explored as a viable solution for transporting high electrical power in the AC regime. In order to be competitive against the DC solution, the cables need to have an acceptable level of AC losses. In this contribution, we discuss the main aspects relevant for designing a cable with a sufficiently low AC loss level. To this end, we perform finite-element-method (FEM) simulations to determine the current and field distributions and calculate the AC losses of such cable configuration. For current capacities of 2-5 kA (peak), power cables are assembled from a relatively small number of MgB2 strands. The performance of such cables strongly depends on the current and field distributions, which are in turn influenced by the number and the arrangement of the superconducting components and also by the magnetic properties of supporting materials. Numerical simulations can help to test different cable configurations and provide important insights for optimizing the cable's design. The numerical model includes the field dependence of the superconductor's critical current density Jc(B) as well as the non-linear properties of magnetic materials.

Grilli, F.; Chervyakov, A.; Zermeno, V.; Marian, A.; Grasso, G.; Goldacker, W.; Rubbia, C.

2014-09-01

55

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

56

A novel high input power factor soft-switching single-stage single-phase AC\\/DC\\/AC converter  

Microsoft Academic Search

This paper proposes novel soft-switching single-stage single-phase AC\\/DC\\/AC converter to give high input power factor and low current distortion on the rectifier side and provide clean and stable AC voltage on the inverter side. In the proposed converter, besides operating at constant frequency, all semiconductor devices operate at soft-switching without additional voltage stress and current stress. A significant reduction in

Chien-Ming Wang; Chia-Hao Yang

2005-01-01

57

Solid oxide fuel cell distributed power generation  

SciTech Connect

Fuel cells are electrochemical devices that oxidize fuel without combustion to convert directly the fuel`s chemical energy into electricity. The solid oxide fuel cell (SOFC) is distinguished from other fuel cell types by its all solid state structure and its high operating temperature (1,000 C). The Westinghouse tubular SOFC stack is process air cooled and has integrated thermally and hydraulically within its structure a natural gas reformer that requires no fuel combustion and no externally supplied water. In addition, since the SOFC stack delivers high temperature exhaust gas and can be operated at elevated pressure, it can supplant the combustor in a gas turbine generator set yielding a dry (no steam) combined cycle power system of unprecedented electrical generation efficiency (greater 70% ac/LHV). Most remarkably, analysis indicates that efficiencies of 60 percent can be achieved at power plant capacities as low as 250 kWe, and that the 70 percent efficiency level should be achievable at the two MW capacity level. This paper describes the individual SOFC, the stack, and the power generation system and its suitability for distributed generation.

Veyo, S.E.

1997-12-31

58

FORMOSAT-5 satellite Power Distribution circuitry development  

Microsoft Academic Search

The Power Control and Distribution Unit (PCDU) in FORMOSAT-5 mission acts as the satellite power control and distribution center, is similar to a human heart. One of the modules in the PCDU, named the Power Distribution (PD), the main function provides the rated voltage and current of each power outlet for die satellite unit. When overload or short-circuit happens and

Che Cheng Huang; Chien Kai Tseng; Jia Jing Yeh

2012-01-01

59

Description of a 20 Kilohertz power distribution system  

NASA Technical Reports Server (NTRS)

A single phase, 440 VRMS, 20 kHz power distribution system with a regulated sinusoidal wave form is discussed. A single phase power system minimizes the wiring, sensing, and control complexities required in a multi-sourced redundantly distributed power system. The single phase addresses only the distribution link; mulitphase lower frequency inputs and outputs accommodation techniques are described. While the 440 V operating potential was initially selected for aircraft operating below 50,000 ft, this potential also appears suitable for space power systems. This voltage choice recognizes a reasonable upper limit for semiconductor ratings, yet will direct synthesis of 220 V, 3 power. A 20 kHz operating frequency was selected to be above the range of audibility, minimize the weight of reactive components, yet allow the construction of single power stages of 25 to 30 kW. The regulated sinusoidal distribution system has several advantages. With a regulated voltage, most ac/dc conversions involve rather simple transformer rectifier applications. A sinusoidal distribution system, when used in conjunction with zero crossing switching, represents a minimal source of EMI. The present state of 20 kHz power technology includes computer controls of voltage and/or frequency, low inductance cable, current limiting circuit protection, bi-directional power flow, and motor/generator operating using standard induction machines. A status update and description of each of these items and their significance is presented.

Hansen, I. G.

1986-01-01

60

Input - output linearization control for a three - phase AC\\/DC\\/AC voltage source converter for bidirectional power flow  

Microsoft Academic Search

In this paper the bidirectional power capability of a three-phase AC\\/DC\\/AC voltage-source converter is studied; based on the input-output linearization control theory, which is applied to the inner current loops that are connected in cascade with the outer loops. Both loops (inner and outer) allow a suitable control of the power flow. The controlled system is linearized and decoupled; based

Janeth Alcalá; Víctor Cárdenas; Nancy Visairo

2010-01-01

61

Power Converters for Feeding Asynchronous Traction Motors of Single-Phase AC Vehicles  

Microsoft Academic Search

Asynchronous induction motors are very well suited to powerful traction drives. For electric locomotives and motor coaches with single-phase supply, a power conversion on the vehicle is necessary. Three different types of static power converters for this application are described. Indirect ac converters with direct voltage link have been developed successfully in the past. For indirect ac converters with direct

Wolfgang Lienau; Adolf Muller-Hellmann; Hans-Christoph Skudelny

1980-01-01

62

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

63

Improved SCR ac-motor controller for battery-powered urban electric vehicles  

Microsoft Academic Search

An electric vehicle propulsion system controller which uses an ac induction electric motor as the electrical to mechanical energy conversion unit was designed and developed. The contract program was to design and test 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

Latos

1982-01-01

64

Low-power clock synchronization using electromagnetic energy radiating from AC power lines  

Microsoft Academic Search

Clock synchronization is highly desirable in many sensor networking applications. It enables event ordering, coordinated actuation, energy-efficient communication and duty cycling. This paper presents a novel low-power hardware module for achieving global clock synchronization by tuning to the magnetic field radiating from existing AC power lines. This signal can be used as a global clock source for battery-operated sensor nodes

Anthony Rowe; Vikram Gupta

2009-01-01

65

Optimal operation of distribution power system including distributed generator  

Microsoft Academic Search

A new model for distribution system reconfiguration (DSR) integrated with optimal power flow (OPF) and optimal capacitor switching (OCS) based on a hybrid approach is proposed in this paper. The objective is to minimize the generation cost of the whole distribution power system, and is subject to constraints such as capacity limit of branches, minimum and maximum power limits of

J. Shu; S. S. Quan; L. Z. Zhang

2010-01-01

66

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

E-print Network

In this dissertation the ac-link universal power converters, which are a new class of power converters, are introduced and studied in detail. The inputs and outputs of these converters may be dc, ac, single phase, or multi-phase. Therefore, they can...

Amirabadi, Mahshid

2013-08-07

67

Experiment and MATLAB simulation of electric power steering system based on permanent magnet AC servo motor  

Microsoft Academic Search

Comparing to traditional mechanical hydraulic steering, electric power steering system has the advantages of high efficiency, fast reaction velocity, safety and pollution free, although DC servo motor is generally adopted at present. This work proposes experiment and MATLAB simulation of electric power steering system based on permanent magnet AC servo motor, to prove that permanent magnet AC servo motor can

Li Hongda; Fengxiang Li

2011-01-01

68

Preliminary study of AC power feeders for AGS booster  

SciTech Connect

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

Meth, M.

1992-07-17

69

Preliminary study of AC power feeders for AGS booster  

SciTech Connect

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

Meth, M.

1992-07-17

70

Optimal reactive power flow with distributed generating plants in electric power distribution systems  

Microsoft Academic Search

This paper presents the solution of reactive power flow optimization for electric power distribution systems integrating with distributed generating (Distributed Generator: DG) plants which can support daily load demand. To reduce the total energy losses of the entire system, transformer tap and reactive power injection from available reactive power source are required. The setting of variables based on a particular

U. Leeton; T. Ratniyomchai; T. Kulworawanichpong

2010-01-01

71

An asynchronous ac\\/dc\\/ac link for wind power application  

Microsoft Academic Search

It is proven that an asynchronous ac\\/dc\\/ac electric link is a practical way of converting the kinetic energy in the wind to electrical energy. The ac\\/dc\\/ac link termed a wind energy conversion system (WECS) consists of a wind driven polyphase alternator, rectifier, inductor, and an inverter tied to the existing utility grid. The laboratory investigations studied various alternator types, types

B. T. Merritt

1977-01-01

72

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

73

Hybrid power system intelligent operation and protection involving distributed architectures and pulsed loads  

NASA Astrophysics Data System (ADS)

Efficient and reliable techniques for power delivery and utilization are needed to account for the increased penetration of renewable energy sources in electric power systems. Such methods are also required for current and future demands of plug-in electric vehicles and high-power electronic loads. Distributed control and optimal power network architectures will lead to viable solutions to the energy management issue with high level of reliability and security. This dissertation is aimed at developing and verifying new techniques for distributed control by deploying DC microgrids, involving distributed renewable generation and energy storage, through the operating AC power system. To achieve the findings of this dissertation, an energy system architecture was developed involving AC and DC networks, both with distributed generations and demands. The various components of the DC microgrid were designed and built including DC-DC converters, voltage source inverters (VSI) and AC-DC rectifiers featuring novel designs developed by the candidate. New control techniques were developed and implemented to maximize the operating range of the power conditioning units used for integrating renewable energy into the DC bus. The control and operation of the DC microgrids in the hybrid AC/DC system involve intelligent energy management. Real-time energy management algorithms were developed and experimentally verified. These algorithms are based on intelligent decision-making elements along with an optimization process. This was aimed at enhancing the overall performance of the power system and mitigating the effect of heavy non-linear loads with variable intensity and duration. The developed algorithms were also used for managing the charging/discharging process of plug-in electric vehicle emulators. The protection of the proposed hybrid AC/DC power system was studied. Fault analysis and protection scheme and coordination, in addition to ideas on how to retrofit currently available protection concepts and devices for AC systems in a DC network, were presented. A study was also conducted on the effect of changing the distribution architecture and distributing the storage assets on the various zones of the network on the system's dynamic security and stability. A practical shipboard power system was studied as an example of a hybrid AC/DC power system involving pulsed loads. Generally, the proposed hybrid AC/DC power system, besides most of the ideas, controls and algorithms presented in this dissertation, were experimentally verified at the Smart Grid Testbed, Energy Systems Research Laboratory. All the developments in this dissertation were experimentally verified at the Smart Grid Testbed.

Mohamed, Ahmed

74

Phosphor-in-glass for high-powered remote-type white AC-LED.  

PubMed

The high-powered alternating current (AC) light-emitting diode (LED) (AC-LED), featuring low cost, high energy utilization efficiency, and long service life, will become a new economic growth point in the field of semiconductor lighting. However, flicker of AC-LED in the AC cycles is not healthy for human eyes, and therefore need to be restrained. Herein we report an innovation of persistent "phosphor-in-glass" (PiG) for the remote-type AC-LED, whose afterglow can be efficiently activated by the blue light. It is experimentally demonstrated that the afterglow decay of PiG in the microsecond range can partly compensate the AC time gap. Moreover, the substitution of inorganic glass for organic resins or silicones as the encapsulants would bring out several technological benefits to AC-LED, such as good heat-dissipation, low glare, and excellent physical/chemical stability. PMID:25329651

Lin, Hang; Wang, Bo; Xu, Ju; Zhang, Rui; Chen, Hui; Yu, Yunlong; Wang, Yuansheng

2014-12-10

75

Dynamic Modeling and Resilience for Power Distribution  

E-print Network

- lytical formulation for large-scale failure and recovery of power distribution induced by severe weather resilience is then defined based on the model. Using the model and large-scale real data from Hurricane Ike--Resilience of power distribution is pertinent to the energy grid under severe weather. This work develops an ana

Ji, Chuanyi

76

Distributed power allocation for vehicle management systems  

Microsoft Academic Search

We consider the problem of designing distributed control protocols -for aircraft vehicle management systems-that cooperatively allocate electric power while meeting certain higher level goals and requirements, and dynamically reacting to the changes in the internal system state and external environment. A decentralized control problem is posed where each power distribution unit is equipped with a controller that implements a local

Necmiye Ozay; Ufuk Topcu; Richard M. Murray

2011-01-01

77

Passive vs. active AC-DC Power conversion in Variable Frequency aerospace applications  

Microsoft Academic Search

The issue of passive vs. active AC-DC power conversion in Variable Frequency (VF) aerospace applications has been addressed. The analysis aimed at examining power quality figures in the two approaches has been performed and performance results against the industry governing standards have been obtained. A Space Vector Pulse-Width-Modulation (SVPWM) switching AC-DC power converter, employing a frequency tracking algorithm and operating

Novica A. Losic

2009-01-01

78

Distributed Power Allocation in Prosumer Thiagarajan Ramachandran,  

E-print Network

@ece.gatech.edu) Abstract: Due to requirements of renewable and distributed energy integration,sustainability and energy to the power grid. As renewable re- sources drop in cost and approach price parity with fossil power blackout. Each type of power system, such electric utilities, microgrids and buildings need to address

Egerstedt, Magnus

79

Power laws, Pareto distributions and Zipf's law  

Microsoft Academic Search

When the probability of measuring a particular value of some quantity varies inversely as a power of that value, the quantity is said to follow a power law, also known variously as Zipf's law or the Pareto distribution. Power laws appear widely in physics, biology, earth and planetary sciences, economics and finance, computer science, demography and the social sciences. For

Mej Newman

2005-01-01

80

Hierarchical analysis of power distribution networks  

Microsoft Academic Search

Careful design and verification of the power distribution network of a chip are of critical importance to ensure its reliable performance. With the increasing number of transistors on a chip, the size of the power network has grown so large as to make the verification task very challenging. The available computational power and memory resources impose limitations on the size

Min Zhao; Rajendran V. Panda; Sachin S. Sapatnekar; Tim Edwards; Rajat Chaudhry; David Blaauw

2000-01-01

81

Hierarchical analysis of power distribution networks  

Microsoft Academic Search

Careful design and verification of the power distribution network of a chip are of critical importance to ensure its reliable performance. With the increasing number of transistors on a chip, the size of the power network has grown so large as to make the verification task very challenging. The available computational power and memory resources impose limitations on the size

Min Zhao; Rajendran V. Panda; Sachin S. Sapatnekar; David T. Blaauw

2002-01-01

82

Distribution Power Flow in IRW Group Meeting  

E-print Network

in GridLabD power flow module #12;Relationships between objects in GridLabD power flow module #12;Line feeder Data: Geometric mean radius of phase lines and the neutral line; Resistance of lines in ohm / mileDistribution Power Flow in GridLabD IRW Group Meeting June 18, 2010 Chengrui Cai #12;Nearly all

Tesfatsion, Leigh

83

Grid-connected distributed solar power systems  

Microsoft Academic Search

This paper discusses some important, though often ignored, technical and economic issues of distributed solar power systems: protection of the utility system and nonsolar customers requires suitable interfaced equipment. Purchase criteria must mirror reality; most analyses use life-cycle costing with low discount rates - most buyers use short payback periods. Distributing, installing, and marketing small, distributed solar systems is more

R. Moyle; H. Chernoff; T. Schweizer

1982-01-01

84

A sensor to detect the DC bias of distribution power transformers  

Microsoft Academic Search

The widespread use of power converters in low- voltage distribution grids has given rise to issues regarding the power quality. In fact, non-linear loads such as AC Drives, switching-mode power supplies and grid-connected converters can cause, besides the generation of several current harmonics, also a DC current component injection into the grid. This DC current component can lead to magnetic

Giampaolo Buticchi; Emilio Lorenzani

2011-01-01

85

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

E-print Network

The Hybrid Power Flow Controller A New Concept for Flexible AC Transmission Jovan Z. Bebic Electric flow controller topologies are proposed for flexible AC transmission systems (FACTS). The first one shunt connected current­sourced converters around a series connected reactive element. In both cases

Lehn, Peter W.

86

Solar power generation and distribution  

NASA Technical Reports Server (NTRS)

The production of electricity from solar energy is discussed. The economics of the proposed generation and distribution systems are analyzed. The use of photovoltaics for converting solar energy to home heating is proposed. The problems of energy distribution are analyzed from the standpoint of equipment costs and complexity.

1973-01-01

87

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

88

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

89

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

90

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false AC-powered adjustable hospital bed. 880.5100 Section 880.5100 ...CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices §...

2010-04-01

91

Power distribution and endogenous segregation  

Microsoft Academic Search

The aim of this paper is to provide a detailed analysis of the process of segregation formation. The claim is that segregation does not originate from prejudice or exogenous psychological factors. Rather it is the product of strategic interactions among social groups in a setting where one group has captured power. While using a model featuring random matching and repeated

Catherine Bros

2008-01-01

92

Channel order and RMS delay spread estimation for AC power line communications  

Microsoft Academic Search

AC power lines have been considered as a convenient and low-cost medium for intra-building automation systems. We investigate the problem of estimating the channel order and root mean squared (RMS) delay spread associated with the power lines, which are channel parameters that provide important information for determining the data transmission rate and designing appropriate equalization techniques for power line communications

Hongbin Li; Zhaoqiang Bi; Duixian Liu; Jian Li; P. Stoica

2000-01-01

93

Power-Law Distributions in Empirical Data  

Microsoft Academic Search

Power-law distributions occur in many situations of scientific interest and\\u000ahave significant consequences for our understanding of natural and man-made\\u000aphenomena. Unfortunately, the detection and characterization of power laws is\\u000acomplicated by the large fluctuations that occur in the tail of the\\u000adistribution -- the part of the distribution representing large but rare events\\u000a-- and by the difficulty of

Aaron Clauset; Cosma Rohilla Shalizi; Mark E. J. Newman

2009-01-01

94

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

95

High frequency power distribution system  

NASA Technical Reports Server (NTRS)

The objective of this project was to provide the technology of high frequency, high power transmission lines to the 100 kW power range at 20 kHz frequency. In addition to the necessary design studies, a 150 m long, 600 V, 60 A transmission line was built, tested and delivered for full vacuum tests. The configuration analysis on five alternative configurations resulted in the final selection of the three parallel Litz straps configuration, which gave a virtually concentric design in the electromagnetic sense. Low inductance, low EMI and flexibility in handling are the key features of this configuration. The final design was made after a parametric study to minimize the losses, weight and inductance. The construction of the cable was completed with no major difficulties. The R,L,C parameters measured on the cable agreed well with the calculated values. The corona tests on insulation samples showed a safety factor of 3.

Patel, Mikund R.

1986-01-01

96

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

97

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

98

Distributed Control System for Cogenerative Power Plants  

Microsoft Academic Search

The paper presents a distributed control system for the realization of cogenerative supply of electricity and heat and, in given case, for their combination with waste heat recovery, particularly in combined (gas-steam) cycle industrial power plants. Modern electric power plants are large complex systems with many processes whose operations need to be optimized. The electrical networks are designed for transmission,

F. Hartescu; I. Miciu

99

Space Solar Power Management and Distribution (PMAD)  

NASA Technical Reports Server (NTRS)

This paper presents, in viewgraph form, SSP PMAD (Space Solar Power Management and Distribution). The topics include: 1) Architecture; 2) Backside Thermal View; 3) Solar Array Interface; 4) Transformer design and risks; 5) Twelve phase rectifier; 6) Antenna (80V) Converters; 7) Distribution Cables; 8) Weight Analysis; and 9) PMAD Summary.

Lynch, Thomas H.

2000-01-01

100

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

101

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

102

Coordinating the dc power injections of a multiterminal HVDC system for dynamic control of AC line flows  

SciTech Connect

As more dc terminals, in the form of links or multiterminal systems, come into operation, the opportunity for controlling ac line flows using the injected dc powers increases. This paper describes a study undertaken to determine the feasibility of using an on-line method to coordinate the dc injections of a multiterminal dc system to dynamically control the power flows in certain ac lines of an integrated ac-dc power system. The proposed controller can be used to steer and to regulate the power flows, and also to damp the power oscillations in these ac lines. The effectiveness of the controller is demonstrated using a transient simulation program.

Hamzei-Nejad, A.; Ong, C.M.

1986-05-01

103

A novel method for recovery of drainage power from distribution transformers  

Microsoft Academic Search

Non-linear loads have become a larger percentage of the total load in commercial facilities. The use of non-linear loads results in excessive injection of harmonic components from the customer facility onto the utility power system. Conventional distribution transformers are of delta-star type, providing 3-phase 4-wire ac distribution. In such a case, the triplen harmonic currents caused due to non-linear loads

P. S. Chandramohanan Nair

2011-01-01

104

Vibration Monitoring of Power Distribution Poles  

SciTech Connect

Some of the most visible and least monitored elements of our national security infrastructure are the poles and towers used for the distribution of our nation’s electrical power. Issues surrounding these elements within the United States include safety such as unauthorized climbing and access, vandalism such as nut/bolt removal or destructive small arms fire, and major vandalism such as the downing of power poles and towers by the cutting of the poles with a chainsaw or torches. The Idaho National Laboratory (INL) has an ongoing research program working to develop inexpensive and sensitive sensor platforms for the monitoring and characterization of damage to the power distribution infrastructure. This presentation covers the results from the instrumentation of a variety of power poles and wires with geophone assemblies and the recording of vibration data when power poles were subjected to a variety of stimuli. Initial results indicate that, for the majority of attacks against power poles, the resulting signal can be seen not only on the targeted pole but on sensors several poles away in the distribution network and a distributed sensor system can be used to monitor remote and critical structures.

Clark Scott; Gail Heath; John Svoboda

2006-04-01

105

Architecture of a Network-in-the-Loop Environment for Characterizing AC Power-System Behavior  

Microsoft Academic Search

This paper describes the method by which a large hardware-in-the-loop environment has been realized for three-phase ac power systems. The environment allows an entire laboratory power-network topology (generators, loads, controls, protection devices, and switches) to be placed in the loop of a large power-network simulation. The system is realized by using a real-time power-network simulator, which interacts with the hardware

Andrew J. Roscoe; Andrew Mackay; Graeme M. Burt; J. R. McDonald

2010-01-01

106

Power and DC link voltage control considerations for indirect AC\\/AC Modular Multilevel Converters  

Microsoft Academic Search

A highly interesting application field of the Modular Multilevel Converter is the interconnection of the European three-phase 50 Hz industrial grid with the single-phase 16 2 =3 Hz railway supply. Contrary to existing technologies, the utilization of a bulky and costly transformer on the low frequency side as well as additional filtering components on the AC lines or DC link

Michail Vasiladiotis; Stephan Kenzelmann; Nicolas Cherix; Alfred Rufer

2011-01-01

107

Research activities on the environmental impact of AC and DC power transmission systems  

Microsoft Academic Search

The panelist speaks about the extensive research carried out by Canadian utilities on the corona and environmental performance ac transmission lines, particularly at 500 kV and 735 kV. Research activities were also pursued to evaluate the technical feasibility of ac transmission at even higher voltages, up to 1500 kV. Significant efforts were devoted in Canada to the investigation of power

P. S. Maruvada

2006-01-01

108

Soft switched capacitively coupled DC-AC converter for high power  

Microsoft Academic Search

A capacitively coupled DC-AC power converter which is capable of zero current soft switching is presented. A form of amplitude modulation is introduced to provide a sinusoidal output waveform. Due to its favorable current stresses on the switches, this converter is suitable for high current high power inductive load applications. With this technique, switching losses can be reduced. The soft

M. Ehsani; T. S. Wu

1993-01-01

109

Nonlinear control for AC\\/DC power system with nonlinear loads  

Microsoft Academic Search

In view of the nonlinearity of loads and HVDC in power systems, the M derivative, M bracket and MIMO feedback linearization based on nonlinear differential algebraic system (NDAS) are introduced into the design of nonlinear controller for parallel AC\\/DC power system. Bronovsky normal form for NDAS is derived when the M relative degree of NDAS is less than its dimension

G. H. Xu; C. Chen; J. Wang; D. D. Li

2004-01-01

110

Channel order and RMS delay spread estimation with application to AC power line communications  

Microsoft Academic Search

AC power lines have been considered as a convenient and low-cost medium for intra-building automation systems. In this paper, we investigate the problem of estimating the channel order and root mean squared (RMS) delay spread associated with the power lines, which are channel parameters that provide important information for determining the data transmission rate and designing appropriate equalization techniques for

Hongbin Li; Duixian Liu; Jian Li; Petre Stoica

2003-01-01

111

Channel order and RMS delay spread estimation with application to AC power line communications  

Microsoft Academic Search

AC power lines have been considered as a convenient and low-cost medium for intra-building automation systems. In this paper, we investigate the problem of estimating the channel order and root mean squared (RMS) delay spread associated with the power lines, which are channel parameters that provide important information for determining the data transmission rate and designing appropriate equalization techniques for

Hongbin Li; Duixian Liu; Jian Li; Petre Stoica

2004-01-01

112

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

NASA Technical Reports Server (NTRS)

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.

1982-01-01

113

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

NASA Technical Reports Server (NTRS)

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

Nola, F. J. (inventor)

1984-01-01

114

AC power quality improvement for line-commutated inverters in photovoltaic applications  

NASA Astrophysics Data System (ADS)

The optimization and testing of a line-commutated inverter (LCI) for linking photovoltaic arrays to utility ac systems are reported. A parity simulator is used to optimize both the basic LCI circuit and the prototype device at the operating parameters, ac line = 240 V ac, single phase; dc voltage = 200 V; dc current = 40 A; and firing angle = 160 deg. The design of the harmonic filter and power-factor-compensation network (using the parity simulator to determine the component values) is explained, and the waveforms obtained with the basic, improved-simulation, and improved-prototype LCIs are shown. Although a power-quality standard has not yet been established, the OEM selling price (in quantities of 1000) of a production LCI with power factor 0.88, ITHD 12 percent, and efficiency 93 percent, is estimated at 25 cents/watt, including the required isolation transformer.

Pautzke, A. W.

115

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

116

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

117

AC\\/DC pulse power conversion from high voltage network to JET loads  

Microsoft Academic Search

The ac-dc pulse power conversion equipment for the Joint European Torus is described; the 1-GW pulse power rating of the conversion equipment is made possible by a flywheel-motor-generator set for the poloidal field load. A power of 500 MW is supplied by a 400-kV interconnected network of large generating capacity. The step-down and rectifier transformers and the filters for current

D. Ciscato; E. Coccorese; K. I. Selin

1977-01-01

118

Modelling HTc superconductors for AC power loss estimation  

SciTech Connect

AC losses in high-temperature superconductors are modelled as a highly non-linear diffusion process. Two empirical expressions for modelling effective resistivity of the conductor are used. Formulations in terms of both H and E are presented and it is argued, using dimensional analysis, that working with E is numerically more efficient. Typical results calculated using a finite-difference scheme are shown.

Sykulski, J.K.; Stoll, R.L.; Mahdi, A.E.; Please, C.P. [Univ. of Southampton (United Kingdom)] [Univ. of Southampton (United Kingdom)

1997-03-01

119

Power factor control system for ac induction motors  

NASA Technical Reports Server (NTRS)

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

Nola, F. J. (inventor)

1981-01-01

120

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

121

Non-oxidized porous silicon-based power AC switch peripheries  

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

122

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

PubMed

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

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

2012-01-01

123

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

124

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

125

Power Management and Distribution System Developed for Thermionic Power Converters  

NASA Technical Reports Server (NTRS)

A spacecraft solar, bimodal system combines propulsion and power generation into a single integrated system. An Integrated Solar Upper Stage (ISUS) provides orbital transfer capabilities, power generation for payloads, and onboard propulsion to the spacecraft. A key benefit of a bimodal system is a greater payload-to-spacecraft mass ratio resulting in lower launch vehicle requirements. Scaling down to smaller launch vehicles increases space access by reducing overall mission cost. NASA has joined efforts with the Air Force Phillips Laboratory to develop enabling technologies for such a system. The NASA/Air Force bimodal concept uses solar concentrators to focus energy into an integrated power plant. This power plant consists of a graphite core that stores thermal energy within a cavity. An array of thermionic converters encircles the graphite cavity and provides electrical energy conversion functions. During the power generation phase of the bimodal system, the thermionic converters are exposed to the heated cavity and convert the thermal energy to electricity. Near-term efforts of the ISUS bimodal program are focused on a ground demonstration of key technologies in order to proceed to a full space flight test. Thermionic power generation is one key technology of the bimodal concept. Thermionic power converters impose unique operating requirements upon a power management and distribution (PMAD) system design. Single thermionic converters supply large currents at very low voltages. Operating voltages can vary over a range of up to 3 to 1 as a function of operating temperature. Most spacecraft loads require regulated 28-volts direct-current (Vdc) power. A combination of series-connected converters and powerprocessing boosters is required to deliver power to the spacecraft's payloads at this level.

Baez, Anastacio N.

1998-01-01

126

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

E-print Network

, this thesis examines the cause and effects of low power factor and harmonic current in single phase rectifiers; provides a thorough review of previous correction techniques; and presents a new approach for ac to dc rectification with input power factor...

Martinez, Roberto

1994-01-01

127

Relativity, nonextensivity, and extended power law distributions.  

PubMed

A proof of the relativistic theorem by including nonextensive effects is given. As it happens in the nonrelativistic limit, the molecular chaos hypothesis advanced by Boltzmann does not remain valid, and the second law of thermodynamics combined with a duality transformation implies that the parameter lies on the interval [0,2]. It is also proven that the collisional equilibrium states (null entropy source term) are described by the relativistic power law extension of the exponential Juttner distribution which reduces, in the nonrelativistic domain, to the Tsallis power law function. As a simple illustration of the basic approach, we derive the relativistic nonextensive equilibrium distribution for a dilute charged gas under the action of an electromagnetic field . Such results reduce to the standard ones in the extensive limit, thereby showing that the nonextensive entropic framework can be harmonized with the space-time ideas contained in the special relativity theory. PMID:16383791

Silva, R; Lima, J A S

2005-11-01

128

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

129

High-Power Converters and AC Drives IEEE PESC2005 Tutorial  

E-print Network

Current Source Inverters 6. PWM Current Source Rectifiers 7. Voltage Source Inverter (VSI) Fed Drives 8 · Multilevel Voltage Source Inverters N dC Cascaded H-bridge (CHB) Inverter dC Two Level Inverter dC Flying. Current Source Inverter (CSI) Fed Drives Main Topics High-Power Converters and AC Drives Bin Wu 3 Topic 1

Wu, Bin

130

AC Grid with Embedded VSC-HVDC for Secure and Efficient Power Delivery  

Microsoft Academic Search

Increased bulk power transactions in competitive energy markets together with large scale integration of renewable energy sources are posing challenges to high-voltage transmission systems. Environmental constraints and energy efficiency requirements also have significant effects on future transmission infrastructure development. This paper reviews the recent development in HVDC technologies and discusses the needs of the hybrid AC\\/DC grid structure for future

Jiuping Pan; Reynaldo Nuqui; Kailash Srivastava; Tomas Jonsson; Per Holmberg; Ying-Jiang Hafner

2008-01-01

131

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

Microsoft Academic Search

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 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

S. Y. R. Hui; I. Oppermann; S. Sathiakumar

1997-01-01

132

Comparative study of asynchronous and synchronous discrete delta modulation schemes for DC-AC power conversion  

Microsoft Academic Search

This paper presents a comparative study on the performance of two discrete delta modulation (DDM) schemes for DC-AC power conversion, namely the asynchronous (ADDM) scheme and the synchronous (SDDM) scheme. The ADDM scheme operates with asynchronous switching frequency and generates harmonics that spread over a wide range of frequency. The SDDM scheme operates with constant switching frequency and generates harmonics

S. Sathiakumar; F. Pasalic; S. Y. R. Hui

1995-01-01

133

Application of SMES Unit in Improving the Performance of an AC\\/DC Power System  

Microsoft Academic Search

This paper investigates the use of a superconducting magnetic energy storage (SMES) unit to improve the performance of an ac\\/dc power system. In this context, investigations have been conducted on a large turbine-generator unit connected to a high- voltage direct current (HVDC) system. The impact of HVDC con- verter station faults on the torsional torques induced in turbine- generator shafts

A. Abu-Siada; Syed Islam

2011-01-01

134

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

135

Feedback stabilization for AC\\/DC power system with nonlinear loads  

Microsoft Academic Search

In view of the nonlinearity of loads and HVDC in power systems, the M derivative, M bracket and multi-input multi-output (MIMO) feedback linearization based on nonlinear differential algebraic system (NDAS) are introduced into the design of nonlinear controller for parallel AC\\/DC power system. Bronovsky normal form for NDAS is derived when the M relative degree of NDAS is less than

Guanghu Xu; Jie Wang; Chen Chen

2005-01-01

136

A DC-AC Power Conversion Technique Using Twin Resonant High-Frequency Links  

Microsoft Academic Search

The advantages of load commUtated high-frequency (HF) sinusoidal inverters as link stiiges in power conversion are well-known. An inverter configuration that employs parallel connection of the load to the resonating capacitor can be employed to realize the high- frequency link. A technique of dc to low-frequency ac power conversion using two, such high-fre4uency links is presented. The frequencies of the

V. T. Ranganathan; Phoivos D. Ziogas

1983-01-01

137

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

Microsoft Academic Search

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

L. J. Kovalsky; R. P. Putkovich

1982-01-01

138

Apparatus for dc\\/ac power conversion by electromagnetic induction  

Microsoft Academic Search

The invention discloses an apparatus for direct current to alternating current power conversion by means of progressive variation of magnetic flux in associated magnetic paths. A direct current input is subdivided into power pulses in two permeance controlled transformers. The pulses are modified, stabilized and recombined in phase opposition to produce a single alternating current output.

Moerman

1979-01-01

139

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

140

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

141

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

142

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

143

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.

144

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

145

Implementation of a Hybrid AC–AC Direct Power Converter With Unity Voltage Transfer  

Microsoft Academic Search

This paper presents a novel hybrid direct power converter (HDPC) which overcomes the two main disadvantages of matrix converters: limited voltage transfer ratio and low immunity to grid disturbance. The proposed converter is formed by integrating a reversible auxiliary boost converter in the dc link of the two-stage matrix converter. Therefore, the HDPC can provide unity voltage transfer ratio even

Thiwanka Wijekoon; Christian Klumpner; Pericle Zanchetta; Patrick W. Wheeler

2008-01-01

146

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

147

COMMUNICATION SYSTEMS AND STUDY METHOD FOR ACTIVE DISTRIBUTION POWER SYSTEMS  

E-print Network

to the distribution power system with active renewable energy based generation units is discussed. Subsequently is configured and studied by the OPNET, and the performance of an active distribution power system integrated1 COMMUNICATION SYSTEMS AND STUDY METHOD FOR ACTIVE DISTRIBUTION POWER SYSTEMS Mu Wei, Zhe Chen

Chen, Zhe

148

Suitable single-phase to three-phase AC-DC-AC power conversion system  

Microsoft Academic Search

This paper presents a single-phase to three-phase power conversion system with parallel rectifier and series inverter to cope with single-phase to three-phase asymmetry. Such converter guarantees both reduction in the input current processed by rectifier circuit and reduction of the output voltage processed by inverter circuit. It is worth to mention that, in spite of proposing a topology with features

E. C. dos Santos; N. Rocha; C. B. Jacobina; R. S. Macena

2012-01-01

149

Distributed power flow calculation for whole networks including transmission and distribution  

Microsoft Academic Search

Traditionally, transmission and distribution power flows are studied separately. But lots of large cities have their hybrid transmission and distribution networks. In order to achieve a global unified power flow solution, transmission and distribution networks are studied as a whole in this paper. Global power flow (GPF) equation is built as a mathematical model for the global power system. Based

Hongbin Sun; Boming Zhang

2008-01-01

150

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

151

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

152

Robust distribution and use of electric power  

NASA Astrophysics Data System (ADS)

One of the major problems related to the simultaneous operation of electrical converters in a wide open power system is the concordance between the characteristics of the feeder itself and the load. Nowadays we usually call Electric Power Quality or Electromagnetic Compatibility to this Concordance Degree. Currently, the most important non concordance are voltage sag (voltage dip) and short time interruptions, that is: decreasings in voltage RMS value lasting from some tenths of a second to several seconds. Current analysis usually study this problem from the feeder side, by means of morphological or stadistical approaches, or from the load side in order to evaluate immunity, emission or specific solutions. This line of research, undoubtly needed provided we need to know the current state of the power system and to increase the concordance degree, is not enough because of the huge variability between power lines and from one instant to another. Moreover, the legal boundaries that can support business decisions are not developed yet. The proposed new theory is widely contrasted by field and laboratory measurement. Detailed analysis include instant voltage, instant current, power system and load effects from many places inside the power system of Spain. This theory is a novel approach to the determination of Concordance Degree (CG) of a whole system (be it a distribution line or a single machine) and to the corrective steps needed to increase it. In addition, the proposed model allow a quantitative evaluation of corrective actions like the increase of energy system storage (in a mechanical to electrical convertible form) or/and the increase of the supplied reactive power. Profitability of corrective actions is mainly a function of the number of voltage dips (sags) and short time interruptions that happen in a given period of time. To reduce this number we have studied and developed new fault characterization and location algorithms designed specifically for medium voltage networks. These algorithms, applied to the recorded faults obtained in the widespread measure campaign we have performed, have allowed the analysis of the Fault Repeatness. Last, new lines of research are suggested, mainly focused on more detailed analytical models together with laboratory and field experiences, in order to provide a solid ground for the development of a realistic standard environment able to provide the highest Concordance Degree at the lowest system-as-a-whole cost.

Catalan Izquierdo, Saturnino

2001-07-01

153

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.

154

http://power.itp.ac.cn/~suncp/quantum.htm Our Motivation and Recent Studies  

E-print Network

http://power.itp.ac.cn/~suncp/quantum.htm 20108 3()Zeno #12;Our Motivation and Recent Studies 1. D. Z. Xu, Q. Ai, C. P. Sun arXiv:1007.4634 : Derence-Based Quantum Zeno Effect in a Cavity-QED System 2. P.Zhang, Q.Ai, C.P.Sun in preparation Geaneral approach to quatum Zeno/anti-Zeno efect without

Sun, Chang-Pu

155

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

Microsoft Academic Search

This paper compares and evaluates two classes of microprocessor-based random PWM (RPWM) real-time generation schemes for DC-AC power conversion. The practical performance of the RPWM schemes based on mathematical and logical approaches are examined. The proposed schemes exhibit excellent EMC and harmonic content with all low and high order harmonics suppressed, and are suitable for both MOSFET and IGBT inverters

S. Y. R. Hui; I. Oppermann; F. Pasalic; S. Sathiakumar

1995-01-01

156

Interaction between MHD generator and DC-AC power conversion system  

Microsoft Academic Search

Transient characteristics of an MHD power generating system including a DC-AC inverter are analyzed using a time-dependent quasi-one-dimensional approximation. The generator model considered is Faraday type of U-25 class with heavy-oil and air combustion gas. It is found that a short-circuited fault of the invertor may become more serious than an open-circuited fault, resulting in significant gas velocity reduction. An

D. Tanaka

1982-01-01

157

Power quality assessment in electrical utilities including distributed generation unit & hybrid filters under non-ideal source voltage  

Microsoft Academic Search

This paper deals with a hybrid compensation system in electrical utility including a distributed generation (DG) unit under non-ideal source voltages condition. The DG unit consists of a Solid Oxide Fuel Cell (SOFC) as active power source and a three-phase full-bridge DC-AC inverter for power conversion. DG unit is controlled to deliver balanced and sinusoidal current in phase with fundamental

S. H. Hosseini; T. Nouri

2011-01-01

158

A new flexible distributed generation unit for active power generation and harmonic compensation under non-ideal source voltages condition  

Microsoft Academic Search

In this paper a flexible distributed generation (FDG) with a new control scheme is proposed for the purpose of contributing to power generation and harmonic compensation under non-ideal source voltages. The proposed FDG consists of a Solid Oxide Fuel Cell unit (SOFC) as power source and a three-arm full bridge DC-AC PWM inverter as utility interface. The new control scheme

Tohid Nouri; Saeid Ghasemzadeh

2011-01-01

159

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

160

AC/DC Power Flow Computation Based on Improved Levenberg-Marquardt Method  

NASA Astrophysics Data System (ADS)

Under the case of ill-conditioning system, this paper is concerned with the AC/DC power flow calculation. The improved Levenberg-Marquardt (ILM) method with adaptive damping factor selection is applied to solve the AC/DC power flow problem. The main purpose of this paper is as follows: one is to provide comparison reference between Newton method, classical LM method (CLM) and ILM method under the well-conditioning system; the other is to research what is the maximal load withstood by power system, under the case of ill-conditioning. Finally, those methods are tested on the 22-bus, the IEEE 118-bus AC/DC system, respectively. Numerical results indicate that the ILM method has the advantage of fast convergent speed. When expanding loads in a certain extent, ILM method can at least find least square solutions, whereas Newton method and CLM method would divergent, and the convergent property of Newton method can be improved by taking some measurements using the information of a least square solution obtained by ILM method.

Cao, Jia; Yan, Zheng; Fan, Xiang; Xu, Xiaoyuan; Li, Jianhua; Cao, Lu

2015-02-01

161

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

162

A new generalized two-stage direct power conversion topology to independently supply multiple AC loads from multiple power grids with adjustable power loading  

Microsoft Academic Search

Normally, a power converter has one supply port to connect to the power grid and one output port to connect to an AC load that requires variable voltage and variable frequency. Converter topologies with multiple output ports, the so-called multi-drive converters are also used in order to share the cost of an active front-end rectifier. As the trend on the

C. Klumpner; F. Blaabjerg

2004-01-01

163

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

164

Satellite control of electric power distribution  

NASA Technical Reports Server (NTRS)

An L-band frequencies satellite link providing the medium for direct control of electrical loads at individual customer sites from remote central locations is described. All loads supplied under interruptible-service contracts are likely condidates for such control, and they can be cycled or switched off to reduce system loads. For every kW of load eliminated or deferred to off-peak hours, the power company reduces its need for additional generating capacity. In addition, the satellite could switch meter registers so that their readings automatically reflected the time of consumption. The system would perform load-shedding operations during emergencies, disconnecting large blocks of load according to predetermined priorities. Among the distribution operations conducted by the satellite in real time would be: load reconfiguration, voltage regulation, fault isolation, and capacitor and feeder load control.

Bergen, L.

1981-01-01

165

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

166

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

167

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

168

Pulse pattern modulated soft commutation inverter-type AC-DC power converter with harmonic current components reduction in utility power side  

Microsoft Academic Search

In this paper, a circuit topology of a half bridge quasi-resonant ZVS-PWM high frequency inverter type AC-DC converter using IGBTs for the consumer magnetron drive is presented, which can use the high frequency high voltage transformer, voltage doubler and power semiconductor switching devices (IGBTs) used in active voltage clamped quasi-resonant PWM inverters suitable for 100 V utility AC power systems.

Hidenori Shirai; Takayuki Matsushige; Manabu Ishitobi; Takeshi Myoui; Mutsuo Nakaoka; Daisuke Bessyo; Hideki Omori

2002-01-01

169

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. Some of these are sustainable (wind and hydroelectric power plants, solar cells), some are controllableDistributed Power Generation: Requirements and Recommendations for an ICT Architecture Ludger

Appelrath, Hans-Jürgen

170

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

171

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

172

LARGE POWER TRANSFORMER RELIABILITY IMPROVEMENT IN ESKOM DISTRIBUTION  

Microsoft Academic Search

With re-regulation of the electricity distribution industry, growing demand for electricity and aging infrastructure, reliability delivery in South Africa has become a concern. Eskom Distribution recognized that reliability improvement required a lifespan performance study on large power transformers. The paper provides results of a performance study on large power transformers on a section of the Eskom Distribution network. The data

Lester GELDENHUIS; Janine JAGERS; Trevor GAUNT

2007-01-01

173

Testing parameter of the power series distribution of a zero inflated power series model  

Microsoft Academic Search

The Zero Inflated Power Series Distribution (ZIPSD) contains two parameters. The first parameter indicates inflation of zero and the other parameter is that of the Power Series distribution. We provide three asymptotic tests for testing the parameter of Power Series distribution, using an unconditional (standard) likelihood approach, a conditional likelihood approach and a test based on sample mean, respectively. The

M. K. Patil; D. T. Shirke

2007-01-01

174

Input/output harmonic free current link three-phase AC power supply  

NASA Astrophysics Data System (ADS)

The three-phase current link AC to AC power supply, a relatively new topology for AC power supply application, has several potential advantages such as smaller number of magnetic components, lower switching frequency and more rugged operation. Despite this, it has received very little attention by the researchers, and the majority of work found in the literature is confined to the application of voltage type converters in this area. This thesis presents a comprehensive systematic approach for steady state/dynamic analysis and design of three-phase current link AC to AC power supplies. Concept of PWM methods in three-phase current type converters (CTC) is explained and the associated constraints in PWM pattern generation are addressed. Several PWM techniques are described and their performance from different aspects are compared. A steady state analysis is presented based on the Fourier representation of PWM waveforms which allows an accurate prediction of the relationships between the fundamental/harmonic components of the waveforms and other system parameters. Expressions governing various steady state characteristics of the system are derived. A dynamic model using the concept of local average of signals is established. The agreement between the dynamic behavior of switching system and derived model is illustrated. Phenomenon of multiple crossing is explained and the necessary requirement for avoiding such a phenomenon is obtained. The concept of internal model controllers is introduced and its application in the inverter control system for achieving zero steady state error is described. A detailed design procedure is presented. Root-locus method is used to design the system controllers. The applicability of different models in different design problems is discussed. All s-domain designs are verified by time-domain simulations. Experiments are conducted on a 2 KVA, 60 Hz to 50 Hz power supply. A 32 bit DSP-base high performance controller is used to implement the control system. The predicted steady state and dynamic results as well as the time-domain simulations are experimentally verified.

Karshenas, Hamid Reza

175

The AC photovoltaic module is here!  

SciTech Connect

This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module{close_quote}s output is connected directly to the building{close_quote}s conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding). {copyright} {ital 1997 American Institute of Physics.}

Strong, S.J. [Solar Design Associates, Inc., Harvard, Massachusetts 01451-0242 (United States); Wohlgemuth, J.H. [Solarex, 630 Solarex Court, Frederick, Maryland 21701 (United States); Wills, R.H. [Advanced Energy Systems, Inc., P.O. Box 262, Wilton, New Hampshire 03086 (United States)

1997-02-01

176

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

177

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

178

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

179

Distributed power control for cooperative relaying with fixed amplifying gain  

Microsoft Academic Search

To reduce interference and fading effect, the use of power control is the most eligible way. We consider power control in a cooperative communication system consisting of multiple sources and multiple relays and the relay is assumed to be amplify-and-forward. We proposes a new distributed power control algorithm for cooperative relaying(DPCCR). In this distributed algorithm, each source updates its power

Young-Keum Song; Dongwoo Kim

2009-01-01

180

Evolution of power law distributions in science and society  

NASA Astrophysics Data System (ADS)

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.

Jeon, Young-Pyo; McCoy, Benjamin J.

2005-09-01

181

Three Level DC-to-AC Power Inverter for Power Grid Operation  

Microsoft Academic Search

In case of medium voltage (several tens up to hundred volts on DC-side) solar inverter applications a DC- to-DC converter for voltage level adaptation is required in front of the DC-to-AC inverter. This leads to a two-stage concept with accumulation of the losses. In our case a concept was chosen, where the efficiency in each stage is maximized by usage

K. H. EDELMOSER

182

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

183

Space Power Management and Distribution Status and Trends  

NASA Technical Reports Server (NTRS)

An overview of space power management and distribution (PMAD) is provided which encompasses historical and current technology trends. The PMAD components discussed include power source control, energy storage control, and load power processing electronic equipment. The status of distribution equipment comprised of rotary joints and power switchgear is evaluated based on power level trends in the public, military, and commercial sectors. Component level technology thrusts, as driven by perceived system level trends, are compared to technology status of piece-parts such as power semiconductors, capacitors, and magnetics to determine critical barriers.

Reppucci, G. M.; Biess, J. J.; Inouye, L.

1984-01-01

184

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

Microsoft Academic Search

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

Darren Hammell; Mark Holveck; DOE Project Officer

2006-01-01

185

Learning classifiers shape reactive power to decrease losses in power distribution networks  

Microsoft Academic Search

Energy is continuously dissipated in power systems due to electrical resistances in transmission and distribution lines. Part of the losses is due to reactive power that travels back and forth in power lines, all the way from power sources to load points. Capacitors can provide local complementary reactive power that decrease losses. As energy loads vary in intensity and characteristics

J. Federico; V. Gonzalez; C. Lyra

2005-01-01

186

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

187

An AC motor drive with power factor control for low cost applications  

NASA Astrophysics Data System (ADS)

The front-end rectifier followed by a pulse-width modulated voltage source inverter (PWM-VSI) has been a well-established power converter configuration for many industrial drives. The increasing costs on the utility usage, due to power quality regulations, and the need to improve the VA capacity of systems, e.g. off-shore drilling rigs, have increased the interest in the development of power electronic equipment with power factor control capability. Electrical motors consume a large amount of the available electrical energy, and this energy tends to increase due to the massive emerging applications of electrical motor drives in appliances and in industrial processes. Therefore, the improvement of the power factor of these low power drive systems, usually in the range from fractional horse-power (hp) to 1 hp, is of particular interest. For these power ratings, the system configuration usually comprises a single-phase to three-phase type of converter with additional circuitry for power factor control (PFC). However, this approach has an impact on the system cost and packaging. In this work, a new concept of integrating motor and power factor controls by using a single-phase to three-phase DSP based six-switch converter topology is presented. Unlike other configurations using extra switch(es) and/or extra boost inductor, in this circuit the boost action, for input current shaping, is done by the motor leakage inductances. The power factor control and inverter operation are performed by applying two modulating signals to the SPWM control logic of the converter. In this dissertation, the converter operation and a proposed control strategy will be explained. Simulation and experimental results for a DSP based induction motor drive will be provided as proof of concept. The feasibility and potential of this configuration for ac motor drive applications will be established. The impact of this scheme on the machine operation will also be discussed.

Bellar, Maria Dias

2000-10-01

188

Integration of Photovoltaic Distributed Generation in the Power Distribution Grid  

Microsoft Academic Search

Numerous North American utilities are integrating growing numbers of investor-owned photovoltaic distributed generation (PV-DG) plants into their distribution systems to comply with state-mandated Renewable Portfolio Standards (RPS). Given the fact that distribution systems have been designed to be operated in a radial fashion, interconnection of PV-DG may lead to significant impacts on planning and operations that need to be studied

Miroslav M. Begovic; Insu Kim; Damir Novosel; Julio Romero Aguero; Ajeet Rohatgi

2012-01-01

189

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 relative cost, solar electric energy systems have yet to be exploited on a widespread basis. It is believed

Sanders, Seth

190

Two samples test for discrete power-law distributions  

E-print Network

Power-law distributions occur in wide variety of physical, biological, and social phenomena. In this paper, we propose a statistical hypothesis test based on the log-likelihood ratio to assess whether two samples of discrete data are drawn from the same power-law distribution.

Bessi, Alessandro

2015-01-01

191

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

192

Enhancement of power system quality using distributed generation  

Microsoft Academic Search

The global demand for energy is increasing at a breathtaking pace. This sharp increase in world energy demand will require significant investment in new power generating capacity and grid infrastructure. Considering the present energy scenario and the degrading environmental conditions, distributed generation seems to be a promising option. Distributed Generation generally refers to small-scale electric power generators that produce electricity

H. D. Mathur

2010-01-01

193

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

194

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

195

Beijing heat-power-gas co-distribution system  

Microsoft Academic Search

Beijing heat-power-gas network couples through coal-fired cogeneration power plants, gas-fired combined cycle cogeneration power plants and gas-fired peak-load boilers. With the development of Beijing urban natural gas popularization, the local imbalance of gas demand and supply proves to be particularly pronounced, which arouses the necessity of co­ distribution from a systematic perspective. The structure and functions of co-distribution platform was

Yang Jinning; Xue Yali; Li Zheng; Tian Yunfeng; Huang Baohua

2011-01-01

196

SELFMONITORING DISTRIBUTED MONITORING SYSTEM FOR NUCLEAR POWER PLANTS (PRELIMINARY VERSION)  

E-print Network

SELF­MONITORING DISTRIBUTED MONITORING SYSTEM FOR NUCLEAR POWER PLANTS (PRELIMINARY VERSION) Aldo and identification are extremely important activities for the safety of a nuclear power plant. In particular inside huge and complex production plants. 1 INTRODUCTION Safety in nuclear power plants requires

197

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

198

Power Flow Control of a Single Distributed Generation Unit  

Microsoft Academic Search

This research addresses power flow control problem of a grid-connected inverter in distributed generation applications. A real and reactive power control solution is proposed on the basis of an existing voltage control strategy developed for island operations. The power control solution takes advantage of a newly designed system parameter identification method and a nonlinear feedforward algorithm, both of which are

Min Dai; Mohammad Nanda Marwali; Jin-Woo Jung; Ali Keyhani

2008-01-01

199

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

200

Local control of reactive power by distributed photovoltaic generators  

SciTech Connect

High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may severely degrade power quality due to voltage sags and swells caused by rapidly varying PV generation during cloud transients coupled with the slow response of existing utility compensation and regulation equipment. 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 suggest a local control scheme that dispatches reactive power from each PV inverter based on local instantaneous measurements of the real and reactive components of the consumed power and the real power generated by the PVs. Using one adjustable parameter per circuit, we balance the requirements on power quality and desire to minimize thermal losses. Numerical analysis of two exemplary systems, with comparable total PV generation albeit a different spatial distribution, show how to adjust the optimization parameter depending on the goal. Overall, this local scheme shows excellent performance; it's capable of guaranteeing acceptable power quality and achieving significant saving in thermal losses in various situations even when the renewable generation in excess of the circuit own load, i.e. feeding power back to the higher-level system.

Chertkov, Michael [Los Alamos National Laboratory; Turitsyn, Konstantin [Los Alamos National Laboratory; Sulc, Petr [Los Alamos National Laboratory; Backhaus, Scott [Los Alamos National Laboratory

2010-01-01

201

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

202

Effect of AC target power on AlN film quality  

SciTech Connect

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

Knisely, Katherine, E-mail: kknisely@umich.edu; Grosh, Karl [Department of Mechanical Engineering, University of Michigan, 2026 GG Brown—2350 Hayward St., Ann Arbor, Michigan 48109 (United States)

2014-09-01

203

Fault Current Issues for Market Driven Power Systems with Distributed Generation  

E-print Network

1 Fault Current Issues for Market Driven Power Systems with Distributed Generation Natthaphob of installing distributed generation (DG) to electric power systems. The proliferation of new generators creates Terms--Distributed / dispersed generation, power distri- bution, power system protection, fault

204

Voltage control of distribution networks with distributed generation using reactive power compensation  

Microsoft Academic Search

Voltage profile of distribution networks with distributed generation are affected significantly due to the integration of distributed generation (DG) on it. This paper presents a way to control voltage of distribution networks with DG using reactive power compensation approach. In this paper, the voltage control approach is shown based on the worst case scenario of the network. To keep the

M. A. Mahmud; M. J. Hossain; H. R. Pota; A. B. M. Nasiruzzaman

2011-01-01

205

Reconfigurable instrumentation system for power distribution modeling  

Microsoft Academic Search

Power transformers' failures carry great costs to electric companies since they need resources to recover from them and to perform periodical maintenance. To avoid this problem in four working 40 MVA transformers, the authors have implemented the measurement system of a failure prediction tool that is the basis of a predictive maintenance infrastructure. The prediction models obtain their inputs from

P. Mariiio; C. Siguenza; F. Poza; M. Ubeira; F. Machado

2003-01-01

206

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

207

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

208

Interaction between MHD generator and dc-ac power conversion system  

NASA Astrophysics Data System (ADS)

Transient characteristics of an MHD power generating system including a DC-AC inverter are analyzed using a time-dependent quasi-one-dimensional approximation. The generator model considered is Faraday type of U-25 class with heavy-oil and air combustion gas. It is found that a short-circuited fault of the invertor may become more serious than an open-circuited fault, resulting in significant gas velocity reduction. An open-circuited fault, if retained for more than 5-8 ms, can substantially increase the gas velocity at the upstream end of the fault region. A protection system composed of a fast-acting DC circuit-breaker and an emergency load resistance is proposed. The switching speed of the DC breaker must be about 500 microsec to stop a pressure increase, resulting, for example, from the short-circuiting of 20 electrode pairs, before it reaches 120% of the initial level.

Tanaka, D.

1983-10-01

209

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

210

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

211

Mecomtronics Module J: Electrical Power Distribution and Loading  

NSDL National Science Digital Library

Initially developed by NJCATE and a team of math, science, communications and technology faculty, this learning module employs the NJCATE Integrated Curriculum Model to integrate core and technical material. Accessing just-in-time learning concepts in which instructors function as coach/facilitators, the module guides students through core and technical activities built around a main project. Module activities present students with hands-on situations which simulate the workplace both in terms of the knowledge and skills required as well as the ethical concerns they will inevitably address. Specifically, Module J's End Cut Saw Machine Station project focuses on electrical power distribution and loading. Students will design a new power distribution system to support the needs of the saw motors and related equipment. The system will consist of a 480-volt feeder and motor control center. A step-down transformer will be provided to supply 120-Volt convenience outlets and general lighting to the area. Using their knowledge of power source, primary Distribution, motors, wiring, and lighting, students will: Design a power distribution system configuration Select, size and specify required power distribution equipment Size and specify required power distribution conduit and cable Size and specify heat tracing cable Produce equipment installation layout drawings Develop project manual and present a project report Target Audience 2-4 Year College Students Self Evaluation DataExcellent instructional module to support a new or existing Engineering Technology course or program.

212

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

213

Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices  

DOEpatents

Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

Chassin, David P. (Pasco, WA); Donnelly, Matthew K. (Kennewick, WA); Dagle, Jeffery E. (Richland, WA)

2006-12-12

214

Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices  

DOEpatents

Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

Chassin, David P. (Pasco, WA); Donnelly, Matthew K. (Kennewick, WA); Dagle, Jeffery E. (Richland, WA)

2011-12-06

215

Independent Orbiter Assessment (IOA): Analysis of the electrical power distribution and control subsystem, volume 1  

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. 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. Of the 1671 failure modes analyzed, 9 single failures were determined to result in loss of crew or vehicle. Three single failures unique to intact abort were determined to result in possible loss of the crew or vehicle. A possible loss of mission could result if any of 136 single failures occurred. Six of the criticality 1/1 failures are in two rotary and two pushbutton switches that control External Tank and Solid Rocket Booster separation. The other 6 criticality 1/1 failures are fuses, one each per Aft Power Control Assembly (APCA) 4, 5, and 6 and one each per Forward Power Control Assembly (FPCA) 1, 2, and 3, that supply power to certain Main Propulsion System (MPS) valves and Forward Reaction Control System (RCS) circuits.

Schmeckpeper, K. R.

1987-01-01

216

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

217

PAD: Power-Aware Directory Placement in Distributed Caches  

E-print Network

PAD: Power-Aware Directory Placement in Distributed Caches Technical Report NWU-EECS-10 structures (i.e., directories) for the purpose of maintaining data coherence in the presence of conflicting and data-access-oblivious placement of the directory structures on chip. In this paper, we propose Power

Shahriar, Selim

218

The need for distribution transformers in Macedonian Power System  

Microsoft Academic Search

In the Macedonian Power System currently are approximately 6000 distribution transformers in exploitation for more than five years. Since their exploitation up to now the makeup of the load served by a transformer change. The numbers energy saving devices, equipment based on power electronics, has drastically increasing, series connected FACTS controllers are more in demand. Extensive use of all this

J. Shikoski; K. Najdenkoski; V. Katic; U. Shikoska; R. Rechkoski

2003-01-01

219

Eocnomic Operation of Distributed Power Systems Within an Electric Utility  

Microsoft Academic Search

The authors evaluate the economic operation of distributed power systems within regional synthetic utilities, analyzing the interactions with the utility of customers who can both buy and sell power. These analyses utilize a linked set of economic, financial and engineering models. SYSGEN, an electric utility system operating model, optimizes annual capacity utilization. SYSGEN provides the operation and maintenance data required

Richard Tabors; Susan Finger; Alan Cox

1981-01-01

220

Intelligent distributed simulation and control of power plants  

Microsoft Academic Search

This paper presents summaries of five research and development activities in intelligent distributed simulation and control of power plants which were presented in a panel session of the same name at the IEEE Power Engineering Society Winter Meeting on February 6, 1997 in New York City. Each of the panelists discussed methods of how they have incorporated intelligent systems techniques

Kwang Y. Lee; Mark Perakis; Donald R. Sevcik; N. I. Santoso; G. K. Lauslerer; Tariq Samad

2000-01-01

221

Impacts of energy storage in distributed Power Generation: A review  

Microsoft Academic Search

Distributed Generation (DG) in the form of Renewable Power Generation systems are currently preferred for clean power generation. However due to their intermittent and unpredictable nature, energy storage needs to be used to ensure that the load is met at all times. There are many possible options for energy storage and the most popular and technologically matured option, batteries, is

G. Coppez; S. Chowdhury

2010-01-01

222

Pricing and Control in the Next Generation Power Distribution System  

Microsoft Academic Search

Smart grid technologies are gaining acceptance and are being integrated into power distribution systems as a result of public and private investment and funding. However, costs of these technologies appear to be a clear obstacle in the widespread integration and maximal use of these technologies. In this paper, the utilization of dollar pricing signals is proposed and illustrated for power

Gerald Thomas Heydt; Badrul H. Chowdhury; Mariesa L. Crow; Daniel Haughton; Brian D. Kiefer; Fanjun Meng; Bharadwaj R. Sathyanarayana

2012-01-01

223

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

224

A study of power conditioning and power distribution and components  

NASA Technical Reports Server (NTRS)

A comprehensive simulation and analysis performed on the operation of the regulator part of the Charger/Battery/Regulator Module (CBRM) are detailed. The CBRM is utilized as an integral component of the Skylab/Apollo Telescope Mount (ATM) electrical power system and contains a switching mode electronic regulator. Implementing circuit analysis techniques, pertinent voltages and currents are calculated; these, in turn, are incorporated into the regulator system study. Investigation of the turn-on and turn-off times associated with the switching circuitry is performed and an examination is made on these calculations. A simulation model computer program is utilized to generate graphs that relate various CBRM parameters to one another.

Horton, H. M.; Honnell, M. A.

1973-01-01

225

Integration of Distributed Generation with Electrical Power System  

Microsoft Academic Search

Distributed Generation is a back-up electric power generating unit that is used in many industrial facilities, hospitals,\\u000a campuses, commercial buildings and department stores. Most of these back-up units are used primarily by customers to provide\\u000a emergency power during times when grid-connected power is unavailable and they are installed within the consumer premises\\u000a where the electric demand is needed. The installation

Khaled Nigim; Doon Campus; Doon Valley

226

Non–zero inflated modified power series distributions  

Microsoft Academic Search

In this paper, we study the class of inflated modified power series distributions (IMPSD) where inflation occurs at any of the support points. This class include among other the generalized Poisson, the generalized negative binomial, the generalized logarithmic series and the lost games distributions. We give expressions for the moments, factorial moments and central moments of the IMPSD. The maximum

M. Murat; D. Szynal

1998-01-01

227

Integrating distribution automation and control techniques into power system curriculum  

Microsoft Academic Search

This panel summary will discuss the integration of research on distribution automation and control techniques into power system curriculum. Specific examples of the classroom and laboratory module enhancements at Drexel University will be discussed. Lecture modules covering advanced techniques for improving distribution operating conditions will be presented. Classroom activities are coupled with hardware and software laboratory modules for students to

Karen Miu; Anthony Deese; Xiaoguang Yang; Valentina Cecchi; Michael Kleinberg; Christian Schegan

2009-01-01

228

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

229

An integrated dc-dc power converter for use in distributed generation power systems  

Microsoft Academic Search

Distributed generation (DG) power systems are becoming increasingly attractive as alternatives to traditional centralized power systems. Fuel cells are an important resource that can be used in such systems, but power electronic converter interfaces are needed to ensure that fuel cells can provide fixed and regulated output voltages as the output of a fuel cell can vary with load. Given

Pritam Das; Gerry Moschopoulos

2008-01-01

230

Influence of distributed generations and renewable energy resources power plant on power system transient stability  

Microsoft Academic Search

This paper analyzing influence of distributed generation (DG) on transient stability of power system network operating parallel with large renewable energy resources (RES) power plant. The study is performed in hypothetical power system network envision in the future which contains a large number of DG. Network behavior when subjected to disturbance is compared with different level of DG penetration. The

Mohd Zamri Che Wanik; István Erlich; Azah Mohamed; Azuki Abdul Salam

2010-01-01

231

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

232

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

233

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

234

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

NASA Astrophysics Data System (ADS)

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.

Duclut, Charlie; Backhaus, Scott; Chertkov, Michael

2013-06-01

235

Wilkinson power divider for antenna distribution networks  

NASA Astrophysics Data System (ADS)

The design, fabrication and experimental evaluation of a Ku-Band 3 dB Wilkinson power divider on high resistivity silicon (HRS) are presented in this paper. The measured insertion for the powder divider is 3.5 dB and isolation between port 2 and 3 is 12 dB respectively. CPW lines were fabricated on two different silicon substrates (HRS, and CMOS grade silicon) and it is shown that the loss characteristics for a 50? CPW patterned on the surface-stabilized HRS is only 0.16 dB at 15GHz. In contrast, the insertion loss for CPW line on CMOS grade silicon is 8.3 dB at 15 GHz. Thus, the low insertion loss could be achieved by stabilizing the surface of HRS with a thin polysilicon layer.

Ji, Taeksoo; Yoon, Hargsoon; Jose, K. A.; Varadan, Vijay K.

2005-05-01

236

A novel four-branches-inverter-based-active-filter for harmonic suppression and reactive compensation of an unbalanced three-phase four-wires electrical distribution systems, feeding AC\\/DC loads  

Microsoft Academic Search

This paper deals with the design, analysis and digital simulation of a novel four-branches-inverter-based-active-filter, that compensates the reactive power and suppress the harmonic currents in the phases and neutral of an unbalanced three-phase four-wires electrical distribution system, feeding AC\\/DC loads. That is, the filter has the capability to instantaneously suppress the harmonics currents, in both the three-phases and the neutral,

Alfredo Nava-Segura; G. Mino-Aguilar

2000-01-01

237

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

238

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

239

Ac-Ac Dual Active Bridge Converter for Solid State Transformer  

E-print Network

converter topologies have been proposed for SST in literatures. A multi-stage ac-dc-ac-dc-ac SST scheme flow. The advantages of direct ac-ac conversion include fewer power conversion stages and minimized single-stage direct ac-ac power conversion to an SST. Fewer conversion stages reduce conduction loss

Kimball, Jonathan W.

240

VST primary mirror active optics power distribution system  

NASA Astrophysics Data System (ADS)

The VST (VLT Survey Telescope), a 2.6 m class Alt-Az telescope in installation phase on Cerro Paranal in Northern Chile, at the European Southern Observatory (ESO) site, is provided with a distributed control system based on electro-mechanical actuators, aimed at implementing the main mirror active optics. Due to the requirement of dissipated power reduction under the mirror, a regulated power bus has been chosen, avoiding the use of voltage regulators mounted on the actuators control board. Because the parallel connection of the all control boards power lines makes this solution critical from the point of view of cabling drop voltage and fault propagation, a Power Distribution System (PDS) provided with remote monitoring and control capabilities has been designed. The PDS configuration is based on several Power Distribution Boxes (PDBs), connected in two separate benches. The harness accommodation was estimated by means of 3D CAD, to evaluate the length of the single power connections. The cabling drop voltage was verified by means of PSpice simulation. The single PDS bench has been provided with drop voltage remote sensing function for all the power supply voltages, while the single PDB has been provided with control and monitoring electronics to disconnect via tele-command the faulty control boards and to monitor in real time voltages and current consumption.

Molfese, C.; Busatta, A.

2008-07-01

241

Comparison of Wind Power and Load Forecasting Error Distributions: Preprint  

SciTech Connect

The introduction of large amounts of variable and uncertain power sources, such as wind power, into the electricity grid presents a number of challenges for system operations. One issue involves the uncertainty associated with scheduling power that wind will supply in future timeframes. However, this is not an entirely new challenge; load is also variable and uncertain, and is strongly influenced by weather patterns. In this work we make a comparison between the day-ahead forecasting errors encountered in wind power forecasting and load forecasting. The study examines the distribution of errors from operational forecasting systems in two different Independent System Operator (ISO) regions for both wind power and load forecasts at the day-ahead timeframe. The day-ahead timescale is critical in power system operations because it serves the unit commitment function for slow-starting conventional generators.

Hodge, B. M.; Florita, A.; Orwig, K.; Lew, D.; Milligan, M.

2012-07-01

242

Determining and exploiting the distribution function of wind power forecasting error for the economic operation of autonomous power systems  

Microsoft Academic Search

Many efforts have been presented in the bibliography for wind power forecasting in power systems and few of them have been used for autonomous power systems. The impact of knowing the distribution function of wind power forecasting error in the economic operation of a power system is studied in this paper. The papers proposes that the distribution of the wind

Antonis G. Tsikalakis; Yiannis A. Katsigiannis; Pavlos S. Georgilakis; Nikos D. Hatziargyriou

2006-01-01

243

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

244

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

245

Impact studies of distributed generation on power quality and protection setup of an existing distribution network  

Microsoft Academic Search

The increasing amount of distributed generation (DG) in distribution networks (DNs) is giving rise to power quality and protection coordination problems. Issues like voltage regulation, flicker, harmonics and loss of coordination between circuit breaker and fuse need to be addressed for integration of DG into DN. This paper discusses these issues with a special emphasis on protection coordination problems. A

B. Hussain; S. M. Sharkh; S. Hussain

2010-01-01

246

Modeling and Verification of Distributed Generation and Voltage Regulation Equipment for Unbalanced Distribution Power Systems; Annual Subcontract Report, June 2007  

SciTech Connect

This report summarizes the development of models for distributed generation and distribution circuit voltage regulation equipment for unbalanced power systems and their verification through actual field measurements.

Davis, M. W.; Broadwater, R.; Hambrick, J.

2007-07-01

247

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

248

Virtual Power Plant: New Solution for Managing Distributed Generations in Decentralized Power Systems  

Microsoft Academic Search

The presence of distributed generation poses new challenges in the management and operation of electrical grids. Distributed generation (wind, combined heat and power, etc.) already accounts for 20% or more of total generation in some electric utilities and this figure is constantly increasing worldwide. With the advent of environmental friendly, small size and efficient generators close to the loads new

Mohamad Amin Salmani; Arash Anzalchi; Soudeh Salmani

2010-01-01

249

Power consumption measurements for ac and pulsed dc for electrostatic coalescence of water-in-oil emulsions  

Microsoft Academic Search

True root mean square power consumption measurements for coalescence of well-defined water-in-oil (W\\/O) emulsions [reverse osmosis water dispersed in Isopar M and stabilized with Paranox 100 surfactant] are presented for a 2-l Teflon insulated electrostatic coalescer. Estimated electricity costs for processing 1000 barrels (42gal basis) of the emulsion were as low as $0.37 and $0.39 under 60Hz ac and pulsed

C.-M Lee; G. W Sams; J. P Wagner

2001-01-01

250

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

251

Pump wavelength and power distribution algorithm in Raman amplifier  

Microsoft Academic Search

An algorithm is discussed to achieve target gain and gain flatness in Raman amplifier through adjusting the pump wavelength and power distribution. It is convenient for Raman amplifier designer to decide the pump wavelength accounting of the trade-off between the gain flattening and gain efficiency. The algorithm based on both the effective interaction lengths and propagation equation, as well as

Xiaobin Hong

2004-01-01

252

Distributional uncertainty analysis using power series and polynomial chaos expansions  

Microsoft Academic Search

This paper provides an overview of computationally efficient approaches for quantifying the influence of parameter uncertainties on the states and outputs of nonlinear dynamical systems with finite-time control trajectories, focusing primarily on computing probability distributions. The advantages and disadvantages of various uncertainty analysis approaches, which use approximate representations of the full nonlinear model using power series or polynomial chaos expansions,

Z. K. Nagy; R. D. Braatz

2007-01-01

253

CDMA based distribution power net automatization and data transmission system  

Microsoft Academic Search

Taking the opportunity of fast growing mobile data communication, this paper proposes a kind of CDMA network based distribution power net automatization and data transmission system, analyzes economic, security, feasibility and up-to-date aspects of the system, and it also carries out simulations on time delay for MAC layer. Based on China Unicorn's CDMA public mobile network platform, this system provides

Wang Hankang; Li Quancheng; Jiang Hai

2005-01-01

254

Using Model Checking for Analyzing Distributed Power Control Problems  

E-print Network

. Realizing that the distributed power control (PC) problem can be modeled by a timed game between a given there is a solution to this conflict of interests. In the literature of PC games the most used solution concept PC. It turns out that it can be applied successfully and allows one to analyze realistic scenarii

Paris-Sud XI, Université de

255

Rooftop Solar Potential Distributed Solar Power in NW  

E-print Network

1 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 on steady increase since early 1990s. From 2000-2010 Solar PV grow at annual rate of 13% and solar thermal

256

Rooftop Solar Potential Distributed Solar Power in NW  

E-print Network

6/19/2013 1 Rooftop Solar Potential Distributed Solar Power in NW Massoud Jourabchi June 2013 1 in 2012 4 #12;6/19/2013 3 Regional Growth In Solar Energy Consumption Solar consumption both Thermal and PV h b t d i i lhas been on steady increase since early 1990s. From 2000-2010 Solar PV grow

257

Islanding detection in power electronic converter based distributed generation  

Microsoft Academic Search

Abstract During the last decades the global warming,and climate changes have been discussed in the media. Simultaneously the electricity consumers ,have experienced higher energy prices and the producers of electricity a rise in the energy consumption.,These factors have strong impacts in the community ,and stimulate further integration of sustainable energy generation in the power system. Significant for distributed energy resources

Daniel Persson

2007-01-01

258

Power flow in distribution networks with earth return  

Microsoft Academic Search

The problems of wave propagation and power flow in the distribution network composed of an overhead wire parallel to the surface of the ground have not been satisfactorily solved. While a complete solution of the actual problem is impossible, as it is explained in the famous Carson's paper (1926), the solution of the problem, where the actual earth is replaced

Rade M. Ciric; Luis F. Ochoa; Antonio Padilha

2004-01-01

259

A Neural Network Based Fault Detector for Power Distribution Systems  

Microsoft Academic Search

This paper presents a fault detector for power distribution systems based on the use of feedforward neural networks. The described method is successfully tested through several simulations. The efficiency of the algorithm to recognize faulty feeders without measuring any voltage in the network and without any threshold is emphasized. Moreover, the sampling frequency of signals and the errors that measuring

Yasmine Assef; Patrick Bastard; Michel Meunier

1997-01-01

260

Fuzzy ARTMAP based forecast of renewable generation for a high frequency AC microgrid  

Microsoft Academic Search

A single phase high frequency AC (HFAC) microgrid is a novel solution towards integration of renewable energy sources in a distributed generation system. Power flow and power quality issues in the HFAC microgrid are controlled by the active filtering solutions called universal active power line conditioner (UPLC) and unified power quality conditioner (UPQC) respectively. After power quality and power flow

Sudipta Chakraborty; Marcelo G. Simões

2005-01-01

261

Econophysical Dynamics of Market-Based Electric Power Distribution Systems  

E-print Network

As energy markets begin clearing at sub-hourly rates, their interaction with load control systems becomes a potentially important consideration. A simple model for the control of thermal systems using market-based power distribution strategies is proposed, with particular attention to the behavior and dynamics of electric building loads and distribution-level power markets. Observations of dynamic behavior of simple numerical model are compared to that of an aggregate continuous model. The analytic solution of the continuous model suggests important deficiencies in each. The continuous model provides very valuable insights into how one might design such load control system and design the power markets they interact with. We also highlight important shortcomings of the continuous model which we believe must be addressed using discrete models.

Nicolas Ho; David P. Chassin

2006-02-09

262

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

263

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

264

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

265

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

266

Experimental study of loss mechanisms of AgAu\\/PbBi-2223 tapes with twisted filaments under perpendicular AC magnetic fields at power frequencies  

Microsoft Academic Search

AC losses under perpendicular AC fields have been measured at 77 K and power frequencies for multifilamentary AgAu (10 wt.%)\\/Bi-2223 tapes with filaments twisted at different pitches. Using simultaneous measurements of the first and higher harmonics of the voltage induced in the pick-up coil, the main loss contributions (superconductor and coupling current losses) have been obtained separately. At power frequencies,

E. Mart??nez; Y. Yang; C. Beduz; Y. B. Huang

2000-01-01

267

Experimental Research on the Effect of Axial Power Distribution on Critical Power  

NASA Astrophysics Data System (ADS)

This paper concerns experimental research to ascertain the effect of axial power distribution on critical power in the positive quality region. Experiments took place at atmospheric pressure in a circular tube. Axial uniform heating and two other axial non - uniform heating cases were selected for detailed evaluation. The effects of relative power ratio on critical power, critical quality and critical boiling length were ascertained in detailed evaluations. Using the experimental data, we evaluated existing correlating concepts with critical power. Result showed a combination of the overall power concept (?BT - LB) and the local conditions concept (?BT - qBT) appearing to be promising in correlating present critical power data in axial non - uniform heating conditions.

Liu, Wei; Kureta, Masatoshi; Takase, Kazuyuki

268

Power  

NASA Technical Reports Server (NTRS)

The space station requires an increase in power or energy of at least several orders of magnitude compared to previous space missions. With the requirement up in the range of 10 kilowatt hours, this obviiously requires the development of new technology. Although the power area is very well integrated in the spacecraft itself, it represents a diverse set of components necessary for energy conversion, electronics, and energy distribution. Considerable work is ongoing at NASA Lewis in the power devices development area, including transformers, large area solid-state chips, transistors, and fast recovery diodes. This work is oriented toward eventual application to both AC and DC power conversion approaches. In the energy storage area, there are many options available to fit into the space station representing various degrees of risk and leverage combination, such as the near-term integral-pressure-vessel nickel hydrogen battery, an advanced Ni-H2 battery concept, and the regenrative hydrogen-oxygen system utilizing essentially the Shuttle orbiter type of fuel cell.

Corbett, R.

1984-01-01

269

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

270

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

E-print Network

. Initial testing made on the prototype prove the feasibility of the approach. I. INTRODUCTION increasingly popular, as more and more commercial products with appealing efficiency, audio quality, weight heat sinks, less weight, better integration and thus smaller packages. Due to this, power supply

271

Distributed Power Flow Control: Distributed Power Flow Control using Smart Wires for Energy Routing  

SciTech Connect

GENI Project: Smart Wire Grid is developing a solution for controlling power flow within the electric grid to better manage unused and overall transmission capacity. The 300,000 miles of high-voltage transmission line in the U.S. today are congested and inefficient, with only around 50% of all transmission capacity utilized at any given time. Increased consumer demand should be met in part with more efficient and an economical power flow. Smart Wire Grid’s devices clamp onto existing transmission lines and control the flow of power within—much like how internet routers help allocate bandwidth throughout the web. Smart wires could support greater use of renewable energy by providing more consistent control over how that energy is routed within the grid on a real-time basis. This would lessen the concerns surrounding the grid’s inability to effectively store intermittent energy from renewables for later use.

None

2012-04-24

272

Methods to Mitigate Harmonics In Residential Power Distribution Systems  

NASA Astrophysics Data System (ADS)

The excessive waveform distortions in the present power distribution systems are produced mainly by the large number of residential loads. Such distributed sources of harmonics cannot be easily treated by the traditional mitigation methods, which have been commonly applied for concentrated and easily detectable industrial distorting loads. This thesis presents new harmonic mitigation techniques necessary for managing this new situation. The proposed strategies are supported by several analytical and simulation studies. Different options for both active and passive centralized and distributed filters are investigated and compared to determine their different technical and economic aspects. Overall, the results of extensive studies confirm that the novel zero-sequence harmonic filter and the new scheme of the low-voltage distributed active filters introduced in this thesis are promising solutions for the increasing harmonic problems in residential feeders.

Bagheri, Pooya

273

Distributed renewable power from biomass and other waste fuels  

NASA Astrophysics Data System (ADS)

The world population is continually growing and putting a burden on our fossil fuels. These fossil fuels such as coal, oil and natural gas are used for a variety of critical needs such as power production and transportation. While significant environmental improvements have been made, the uses of these fuels are still causing significant ecological impacts. Coal power production efficiency has not improved over the past thirty years and with relatively cheap petroleum cost, transportation mileage has not improved significantly either. With the demand for these fossil fuels increasing, ultimately price will also have to increase. This presentation will evaluate alternative power production methods using localized distributed generation from biomass, municipal solid waste and other waste sources of organic materials. The presentation will review various gasification processes that produce a synthetic gas that can be utilized as a fuel source in combustion turbines for clean and efficient combined heat and power. This fuel source can produce base load renewable power. In addition tail gases from the production of bio-diesel and methanol fuels can be used to produce renewable power. Being localized can reduce the need for long and costly transmission lines making the production of fuels and power from waste a viable alternative energy source for the future.

Lyons, Chris

2012-03-01

274

Power management and distribution considerations for a lunar base  

NASA Technical Reports Server (NTRS)

Design philosophies and technology needs for the power management and distribution (PMAD) portion of a lunar base power system are discussed. A process is described whereby mission planners may proceed from a knowledge of the PMAD functions and mission performance requirements to a definition of design options and technology needs. Current research efforts at the NASA LRC to meet the PMAD system needs for a Lunar base are described. Based on the requirements, the lunar base PMAD is seen as best being accomplished by a utility like system, although with some additional demands including autonomous operation and scheduling and accurate, predictive modeling during the design process.

Kenny, Barbara H.; Coleman, Anthony S.

1991-01-01

275

An attractive new converter topology for AC\\/DC, DC\\/DC & DC\\/AC power conversion  

Microsoft Academic Search

A new power converter topology is proposed. The new converter is essentially a four-quadrant converter offering several advantages. These include high efficiency, reduced size and weight, excellent dynamic performance, and inherent galvanic isolation. The new topology proposed has the potential for a wide range of applications such as: inverters, rectifiers, and step-up step-down four quadrant converters for special applications. The

G. Cimador; P. Prestifilippo

1990-01-01

276

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

SciTech Connect

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

Kern, G.

1999-04-01

277

A generalized power flow analysis for distribution systems with high penetration of distributed generation  

Microsoft Academic Search

In this paper, the element incidence matrix has been extended to develop a comprehensive three-phase distribution system power flow program for radial topology. Three-phase overhead or underground primary feeders and double-phase or single-phase line sections near the end of the feeder laterals have been considered. Unbalanced loads with different types including constant power, constant current and constant impedance are modeled

Hany E. Farag; E. F. El-Saadany; Ramadan El Shatshat; Aboelsood Zidan

2011-01-01

278

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

279

Power distribution for an Am/Cm bushing melter  

SciTech Connect

Decades of nuclear material production at the Savannah River Site (SRS) has resulted in the generation of large quantities of the isotopes Am{sup 243} and Cm{sup 244}. Currently, the Am and Cm isotopes are stored as a nitric acid solution in a tank. The Am and Cm isotopes have great commercial value but must be transferred to ORNL for processing. The nitric acid solution contains other isotopes and is intensely radioactive, which makes storage a problem and precludes shipment in the liquid form. In order to stabilize the material for onsite storage and to permit transport the material from SRS to ORNL, it has been proposed that the Am and Cm be separated from other isotopes in the solution and vitrified. Vitrification will be effected by depositing a liquid feed stream containing the isotopes in solution, together with a stream of glass frit, onto the top of a molten glass pool in a melter. The glass is non-conducting and the melter is a Platinum/Rhodium alloy vessel which is heated by passing an electric current through it. Because most of the power is required to evaporate the liquid feed at the top of the glass pool, power demands differ for the upper and lower parts of the melter. In addition, the melter is batch fed so that the local power requirements vary with time. In order to design a unique split power supply, which ensures adequate local power delivery, an analysis of the melter power distribution was performed with the ABAQUS finite element code. ABAQUS was used to calculate the electric potential and current density distributions in the melter for a variety of current and potential boundary conditions. The results of the calculation were compared with test data and will be used to compute power densities for input to a computational fluid dynamics model for the melter.

Gong, C.; Hardy, B.J.

1996-12-31

280

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

281

Power-law distribution in Japanese racetrack betting  

E-print Network

Gambling is one of the basic economic activities that humans indulge in. An investigation of gambling activities provides deep insights into the economic actions of people and sheds lights on the study of econophysics. In this paper we present an analysis of the distribution of the final odds of the races organized by the Japan Racing Association. The distribution of the final odds $P_o(x)$ indicates a clear power law $P_o(x)\\propto 1/x$, where $x$ represents the final odds. This power law can be explained on the basis of the assumption that that every bettor bets his money on the horse that appears to be the strongest in a race.

Ichinomiya, T

2006-01-01

282

Robust Distributed Power Control in Cognitive Radio Networks  

E-print Network

We propose a robust distributed uplink power allocation algorithm for underlay cognitive radio networks (CRNs) with a view to maximizing the total utility of secondary users (SUs) when channel gains from SUs to primary base stations, and interference caused by primary users (PUs) to the SUs' base station are uncertain. In doing so, we utilize the worst-case robust optimization to keep the interference caused by SUs to each primary base station below a given threshold, and satisfy the SUs' quality of service for all realizations of uncertainty. We model each uncertain parameter by a bounded distance between its estimated and exact values, and formulate the robust power allocation problem via protection values for constraints. We demonstrate that the convexity of our problem is preserved, and in some cases converts into a geometric programming problem, which we solve via a distributed algorithm by using Lagrange dual decomposition. To reduce the cost of robustness, defined as the reduction in the total utility ...

fard, Saeideh Parsaei

2011-01-01

283

{sky6174, kilmd55}@ccl.snu.ac.kr, jsno@snu.ac.kr, habchung@hongik.ac.kr On the Approximate Maximum Distribution for  

E-print Network

), (cumulative distribution function: cdf) (moment generating function: mgf) Meijer G Gauss F . Pad´e pdf s ) Gm,n p,q [·] 2F1(·, ·; ·; ·) [4] Meijer G-function Gauss hypergeometric function. Ym, m = 1) ] mgf , Meijer G-function . 0 0.5 1 1.5 2 2.5 3 3.5 4 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0

No, Jong-Seon

284

A study of power electronic building block (PEBB)-based integrated shipboard power systems during reconfiguration  

E-print Network

concept with electric propulsion, direct current (DC) distribution, and modular technology. In the all electric ship concept, ship propulsion and ship service loads are powered by alternating current (AC) generation. For the IPS, power electronics...

Adediran, Adeoti Taiwo

2004-09-30

285

Modeling and Analysis of Power Distribution Networks for Gigabit Applications  

Microsoft Academic Search

As the operating frequency of digital systems increases and voltage swing decreases, it becomes increasingly important to accurately characterize and analyze power distribution networks (PDN). This paper presents the modeling, simulation, and measurement of a PDN in a high-speed FR4 printed circuit board (PCB) designed for chip-to-chip communication at a data rate of 3.2 Gbps and above. The test board

Chuck Yuan; Joong-ho Kim; Madhavan Swaminathan

2003-01-01

286

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

E-print Network

of minimizing either the power distribu- tion losses, or, the cost of power drawn from the substation and sup MICROGRIDS are portions of a power distribution net- work located downstream of the distribution substation at the distribution substation [5]. To this end, optimal power flow (OPF) approaches are in- creasingly advocated also

Giannakis, Georgios

287

Klystron Cluster Scheme for ILC High Power RF Distribution  

SciTech Connect

We present a concept for powering the main linacs of the International Linear Collider (ILC) by delivering high power RF from the surface via overmoded, low-loss waveguides at widely spaced intervals. The baseline design employs a two-tunnel layout, with klystrons and modulators evenly distributed along a service tunnel running parallel to the accelerator tunnel. This new idea eliminates the need for the service tunnel. It also brings most of the warm heat load to the surface, dramatically reducing the tunnel water cooling and HVAC requirements. In the envisioned configuration, groups of 70 klystrons and modulators are clustered in surface buildings every 2.5 km. Their outputs are combined into two half-meter diameter circular TE{sub 01} mode evacuated waveguides. These are directed via special bends through a deep shaft and along the tunnel, one upstream and one downstream. Each feeds approximately 1.25 km of linac with power tapped off in 10 MW portions at 38 m intervals. The power is extracted through a novel coaxial tap-off (CTO), after which the local distribution is as it would be from a klystron. The tap-off design is also employed in reverse for the initial combining.

Nantista, Christopher; Adolphsen, Chris; /SLAC

2009-07-06

288

Inverse Power Law distribution and failure initiation of subaerial landslides  

NASA Astrophysics Data System (ADS)

Landslides are sometimes considered together with other natural hazards, such as earthquakes and fires, as a cascading avalanche or self-organized critical process, where the disturbance initiates in one or a few locations and propagates to the entire region. This view stems from numerous studies of subaerial landslides that show an inverse power law size distribution. Inverse power law distributions are the result of additive avalanche processes, in which the final size cannot be predicted at the onset of the disturbance. However, the observation of a large number of small separate subaerial landslides being triggered by a single earthquake, such as the 1994 Northridge earthquake, is incompatible with a cascading hypothesis and suggests instead that failure occurs simultaneously in many locations within the area affected by ground shaking. Unlike submarine landslides, which are found on large uniformly dipping slopes, a single large landslide scarp cannot form on land because of the heterogeneous morphology and short slope distances of tectonically-active subaerial regions. However, for a given earthquake magnitude, the total area affected by subaerial landslides is shown to be comparable to the affected area calculated by slope stability analysis for submarine landslides and is thus predictable. We show a statistical similarity between morphological attributes of the affected area and area distribution of the landslides from the Northridge earthquake, which suggests that area distribution of subaerial landslides may be determined by the morphology of the affected area, not by the initiation process.

ten Brink, U. S.; Barkan, R.; Andrews, B. D.; Chaytor, J. D.

2009-12-01

289

A Three-Phase Single-Stage AC-DC Full Bridge Converter with High Power Factor and Phase-Shift PWM  

Microsoft Academic Search

Converters that integrate the functions of power factor correction (PFC) and isolated dc-dc conversion in a single power converter have been proposed to reduce the cost associated with operating two separate switch-mode converters. Many low power ac-dc single-stage converters have been proposed in the power electronics literature, but very few three-phase single-stage full-bridge converters and these require sophisticated methods of

Dunisha Wijeratne; Gerry Moschopoulos

2009-01-01

290

Abstract--The reliability and quality of power distribution systems are usually affected by many different distribution faults.  

E-print Network

to assist power distribution engineers to design a more effective tree-fault prevention strategy analysis, tree-caused distribution faults. I. INTRODUCTION OWER systems play a very important role in our, and will investigate the influence of several selected factors on the tree faults occurrence. II. POWER DISTRIBUTION

Chow, Mo-Yuen

291

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

292

Voltage Oscillations in Power Distribution Networks in the Presence of DFIGs and Induction Motor Loads  

E-print Network

Voltage Oscillations in Power Distribution Networks in the Presence of DFIGs and Induction Motor, DFIG, eigenvalue, in- duction motor, small-signal stability. I. INTRODUCTION Distributed generation (DG

Pota, Himanshu Roy

293

RF Impedance of United States and European Power Lines  

Microsoft Academic Search

Impedance measurements were made of 86 commercial 50-Hz AC power distribution systems throughout the LF-HF (0.02-30 MHz) spectrum in six European countries. The impedances are those presented to devices\\/appliances connected to the ac power source. The European results are presented in graphic and tabular form and are compared to impedances of U.S. power lines.

John Malack; John Engstrom

1976-01-01

294

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

295

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

296

Application of pulse doubling in delta\\/polygon-connected transformer-based 36-pulse ac-dc converter for power quality improvement  

Microsoft Academic Search

This paper presents a pulse doubling technique in a 36-pulse ac-dc converter which supplies direct torque-controlled motor drives (DTCIMD's) 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

Rohollah Abdollahi; Alireza Jalilian

2012-01-01

297

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

298

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

299

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... and d i s t r i b u t i o n system r e l i a b i l i t y i n d i c e s , namely the number of service interruptions per year and the duration of service i n t e r r u p t i o n , are important for evaluating power system worth and for determining...

Dip, Minh

1978-01-01

300

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

301

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

302

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 January to June 2004 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.

Nguyen Minh

2004-07-04

303

Tailoring Modal Power Distribution in Common-Core Waveguide Arrays  

NASA Astrophysics Data System (ADS)

In this paper, the scattering matrix method (SMM) is used to analyze the modal properties of evanescently coupled waveguide arrays with cores spaced equidistant from a common central core. Propagation constants and field distributions of the fundamental in-phase supermodes are obtained for waveguide arrays comprising three, four, five, six, and seven cores. The authors show how the coupling strength among individual cores can be controlled by adjusting the properties of the central core, thereby providing a means of tailoring the near-field mode profile. By properly selecting the parameters of the central core, the authors also show how an equal power distribution among all cores can be achieved. A seven-core waveguide array is discussed in detail including the effects of varying core spacing and central core parameters on the supermodes and dispersion properties of the array.

Nguyen, Michael; Church, Kenneth

2006-06-01

304

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

305

Utility Grid-Connected Distributed Power Systems National Solar Energy Conference  

E-print Network

Utility Grid-Connected Distributed Power Systems National Solar Energy Conference ASES Solar 96 substation sited, grid-support PV systems totaling 860 kW bringing the SMUD distributed PV power system energy, distributed generation resource. Investments made in solar power today are expected to provide

306

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.

307

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

308

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

309

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)

310

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

311

Power superconducting power transmission cable  

DOEpatents

The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

Ashworth, Stephen P. (Cambridge, GB)

2003-01-01

312

Impact of Increasing Distributed Wind Power and Wind Turbine Siting on Rural Distribution Feeder Voltage Profiles: Preprint  

SciTech Connect

Many favorable wind energy resources in North America are located in remote locations without direct access to the transmission grid. Building transmission lines to connect remotely-located wind power plants to large load centers has become a barrier to increasing wind power penetration in North America. By connecting utility-sized megawatt-scale wind turbines to the distribution system, wind power supplied to consumers could be increased greatly. However, the impact of including megawatt-scale wind turbines on distribution feeders needs to be studied. The work presented here examined the impact that siting and power output of megawatt-scale wind turbines have on distribution feeder voltage. This is the start of work to present a general guide to megawatt-scale wind turbine impact on the distribution feeder and finding the amount of wind power that can be added without adversely impacting the distribution feeder operation, reliability, and power quality.

Allen, A.; Zhang, Y. C.; Hodge, B. M.

2013-09-01

313

Optimal interface based on power electronics in distributed generation systems for fuel cells  

Microsoft Academic Search

A hybrid system comprising a fuel cell stack and a battery bank was developed, built and tested in this research work. This hybrid system was built to supply both DC and AC outputs. The voltage levels set on electrical interconnection points are achieved with several power conditioning stages controlled by Pulse Width Modulation (PWM). The main advantage of this system

J. M. Andújar; F. Segura; E. Durán; L. A. Rentería

2011-01-01

314

Distributed Optimal Power and Rate Control in Wireless Sensor Networks  

PubMed Central

With the rapid development of wireless sensor networks, reducing energy consumption is becoming one of the important factors to extend node lifetime, and it is necessary to adjust the launching power of each node because of the limited energy available to the sensor nodes in the networks. This paper proposes a power and rate control model based on the network utility maximization (NUM) framework, where a weighting factor is used to reflect the influence degree of the sending power and transmission rate to the utility function. In real networks, nodes interfere with each other in the procedure of transmitting signal, which may lead to signal transmission failure and may negatively have impacts on networks throughput. Using dual decomposition techniques, the NUM problem is decomposed into two distributed subproblems, and then the conjugate gradient method is applied to solve the optimization problem with the calculation of the Hessian matrix and its inverse in order to guarantee fast convergence of the algorithm. The convergence proof is also provided in this paper. Numerical examples show that the proposed solution achieves significant throughput compared with exiting approaches. PMID:24895654

Tang, Meiqin; Bai, Jianyong; Li, Jing; Xin, Yalin

2014-01-01

315

Distributed optimal power and rate control in wireless sensor networks.  

PubMed

With the rapid development of wireless sensor networks, reducing energy consumption is becoming one of the important factors to extend node lifetime, and it is necessary to adjust the launching power of each node because of the limited energy available to the sensor nodes in the networks. This paper proposes a power and rate control model based on the network utility maximization (NUM) framework, where a weighting factor is used to reflect the influence degree of the sending power and transmission rate to the utility function. In real networks, nodes interfere with each other in the procedure of transmitting signal, which may lead to signal transmission failure and may negatively have impacts on networks throughput. Using dual decomposition techniques, the NUM problem is decomposed into two distributed subproblems, and then the conjugate gradient method is applied to solve the optimization problem with the calculation of the Hessian matrix and its inverse in order to guarantee fast convergence of the algorithm. The convergence proof is also provided in this paper. Numerical examples show that the proposed solution achieves significant throughput compared with exiting approaches. PMID:24895654

Tang, Meiqin; Bai, Jianyong; Li, Jing; Xin, Yalin

2014-01-01

316

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

317

Reactive power generation by DFIG based wind farms with AC grid connection  

Microsoft Academic Search

Balancing reactive power within a grid is one of the fundamental tasks of transmission system operators. With increasing portion of wind power, wind turbines have to contribute to reactive power generation during steady state as well as during transient conditions. First, this paper provides an overview about the available options to supply reactive power by wind farms typically connected to

I. Erlich; M. Wilch; C. Feltes

2007-01-01

318

Reactive Power Generation by DFIG Based Wind Farms with AC Grid Connection  

Microsoft Academic Search

Reactive power generation by wind farms, which must operate similar to other conventional power plants, is a major concern during both steady state and fault conditions. This paper addresses the reactive power generation of offshore wind parks using doubly-fed induction generators (DFIGs) connected to the main grid with long cables along with reactive power compensating devices. During steady-state operation, reactive

M. Wilch; V. S. Pappala; S. N. Singh; I. Erlich

2007-01-01

319

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

320

Electrochemical characterization and modeling of fuel cells via AC impedance and residence time distribution  

NASA Astrophysics Data System (ADS)

The performance of commercially available fuel cells was tested under a variety of test conditions and models were formulated to explain the experimental results. Several techniques were applied to single cells and groups of cells, each probing a different phenomenon responsible for limiting the power output of the cells. Nonuiformity of fuel cells in a stack can drastically affect the total power output, because a stack of cells in series can only provide as much electrical current as the weakest cell. Uniformity of polymer electrolyte membrane (PEM) fuel cell voltage was measured for each cell of the 47 cells in a Nexa(TM) stack operating with 0 W and 800W supplied to an external load. Manufacturing consistency was assessed by comparing the mean cell potential of 10 different stacks. To minimize the cost of operating a stack, PEM fuel cells must be capable of withstanding higher impurity concentrations, which was accomplished by adding a manual purge line into the fuel exhaust line of a Nexa(TM) stack. The critical flow rate of the anode exhaust was determined by feeding gas diluted with up to 7% N2 to a stack supplying up to 200 W to an external load. The residence time distribution (RTD) of impurities in the stack was evaluated by injecting a pulse of inert gas and simultaneously measuring the time dependent voltage of each cell in the stack. A number of different compartmental flow models were developed to replicate the experimental data, but with minimal success; however, the added exhaust line successfully improved the impurity tolerance of the stack. Determining which and to what extent physical processes limit the electrical output of fuel cells is critical for evaluating system designs and performing diagnostics. Impedance spectroscopy was applied to cells to test the dynamic response of fuel cells and stacks thereof. Equivalent circuit models were fitted to the data, with each circuit element representing a different physical phenomenon. Data were measured at load currents for individual and groups of cells in the Nexa(TM) stack and to solid oxide button cells and larger cells in a 5-cell planar stack. A pulsed load was applied to individual NEXA(TM) stacks and stack pairs in series and parallel, and the dynamic potential response was measured. A similar pulsed load was applied to the stack model to simulate the resulting potential wave, which compared favorably with the experimental data. By testing uniformity, impurity tolerance, and dynamic load response, valuable information about fuel cells has been obtained and may be predicted from the formulated models.

Payne, Robert R. U.

321

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

NASA Astrophysics Data System (ADS)

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

Taylor, Zachariah David

322

Integrating Power Management into Distributed Real-time Systems at Very Low Implementation Cost  

Microsoft Academic Search

The development cost of low-power embedded systems can be significantly reduced by reusing legacy designs and applying proper modifications to meet the new power constraints. The proposed power management techniques in the literature for implementing distributed power managers in multi-processor systems are very costly in terms of hardware and software modifications. For example, extra software code for power management must

Bita Gorjiara; Nader Bagherzadeh; Pai H. Chou

2007-01-01

323

2236 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 22, NO. 4, OCTOBER 2007 Direct Lightning Strikes to Test Power Distribution  

E-print Network

and outages [1]. The design of lightning protection for distribution lines involves weighing the initial cost2236 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 22, NO. 4, OCTOBER 2007 Direct Lightning Strikes of rocket-triggered lightning with two unenergized power distribution lines of about 800 m length

Florida, University of

324

Design of a power management and distribution system for a thermionic-diode powered spacecraft  

NASA Technical Reports Server (NTRS)

The Electrical Systems Development Branch of the Power Technology Division at the NASA Lewis Research Center in Cleveland, Ohio is designing a Power Management and Distribution (PMAD) System for the Air Force's Integrated Solar Upper Stage (ISUS) Engine Ground Test Demonstration (EGD). The ISUS program uses solar-thermal propulsion to perform orbit transfers from Low Earth Orbit (LEO) to Geosynchronous Orbit (GEO) and from LEO to Molnya. The ISUS uses the same energy conversion receiver to perform the LEO to High Earth Orbit (HEO) transfer and to generate on-orbit electric power for the payloads. On-orbit power generation is accomplished via two solar concentrators heating a dual-cavity graphite-core which has Thermionic Diodes (TMD's) encircling each cavity. The graphite core and concentrators together are called the Receiver and Concentrator (RAC). The TDM-emitters reach peak temperatures of approximately 2200K, and the TID-collectors are run at approximately 1000K. Because of the high Specific Impulse (I(sup sp)) of solar thermal propulsion relative to chemical propulsion, and because a common bus is used for communications, GN&C, power, etc., a substantial increase in payload weight is possible. This potentially allows for a stepdown in the required launch vehicle size or class for similar payload weight using conventional chemical propulsion and a separate spacecraft bus. The ISUS power system is to provide 1000W(sub e) at 28+/-6V(sub dc) to the payload/spacecraft from a maximum TID generation capability of 1070W(sub e) at 2200K. Producing power with this quality, protecting the spacecraft from electrical faults and accommodating operational constraints of the TID's are the responsibilities of the PMAD system. The design strategy and system options examined along with the proposed designs for the Flight and EGD configurations are discussed herein.

Kimnach, Greg L.

1996-01-01

325

Molecular clouds have power-law probability distribution functions  

NASA Astrophysics Data System (ADS)

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 Herschel/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 AK ? 0.1 and 0.2 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 AK ? 0.1 mag, limiting our ability to investigate more complex models for the shape of the cloud PDF.

Lombardi, Marco; Alves, João; Lada, Charles J.

2015-04-01

326

Development of a hardware-based AC microgrid for AC stability assessment  

NASA Astrophysics Data System (ADS)

As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

Swanson, Robert R.

327

Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation  

NASA Astrophysics Data System (ADS)

Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified by simulation and experimental tests under various conditions considering all possible cases such as different amounts of voltage sag depth (VSD), different amounts of point-on-wave (POW) at which voltage sag occurs, harmonic distortion, line frequency variation, and phase jump (PJ). Furthermore, the ripple amount of fundamental voltage amplitude calculated by the proposed method and its error is analyzed considering the line frequency variation together with harmonic distortion. The best and worst detection time of proposed method were measured 1ms and 8.8ms, respectively. Finally, the proposed method has been compared with other voltage sag detection methods available in literature. Part 2: Power System Modeling for Renewable Energy Integration: As power distribution systems are evolving into more complex networks, electrical engineers have to rely on software tools to perform circuit analysis. There are dozens of powerful software tools available in the market to perform the power system studies. Although their main functions are similar, there are differences in features and formatting structures to suit specific applications. This creates challenges for transferring power system circuit models data (PSCMD) between different software and rebuilding the same circuit in the second software environment. The objective of this part of thesis is to develop a Unified Platform (UP) to facilitate transferring PSCMD among different software packages and relieve the challenges of the circuit model conversion process. UP uses a commonly available spreadsheet file with a defined format, for any home software to write data to and for any destination software to read data from, via a script-based application called PSCMD transfer application. The main considerations in developing the UP are to minimize manual intervention and import a one-line diagram into the destination software or export it from the source software, with all details to allow load flow, short circuit and other analyses. In this study, ETAP, OpenDSS, and GridLab-D are considered, and PSCMD trans

Khoshkbar Sadigh, Arash

328

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

329

Control of Parallel-Connected Bidirectional AC-DC Converters in Stationary Frame for Microgrid  

E-print Network

-- With the penetration of renewable energy in modern power system, microgrid has become a popular application worldwide energy sources [3-6]. A hybrid microgrid can be made up of distributed renewable source, AC and DC commonControl of Parallel-Connected Bidirectional AC-DC Converters in Stationary Frame for Microgrid

Teodorescu, Remus

330

Study on Fuzzy Dynamic Programming for Optimization of Reactive Power Compensation of Power System Including Distributed Generation  

Microsoft Academic Search

According to limitation of traditional methods, a new optimization model of reactive power compensation of power system including distributed generation is proposed, in which investment of the equipment, electrovalence and other factors of the complex power network are considered. According to the optimization model, an optimization scheme of fuzzy dynamic programming is introduced, in which fuzzy theory is used to

Peng Peng; Shi-ping Su; Xi Luo; Li-quan Fan

2008-01-01

331

An impedance profile of a commercial power grid and a tester power distribution system is developed in this paper.  

E-print Network

in measurement resolution derives from the fil- tering characteristics of the resistive, capacitive and inducAbstract An impedance profile of a commercial power grid and a tester power distribution system is developed in this paper. The profile is used to identify the measurable frequency range of the power supply

Plusquellic, James

332

Sensorless Operation of a PWM Rectifier for a Distributed Generation  

Microsoft Academic Search

This paper presents a power converter configuration interfaced with the distributed ac power generation system to regulate the dc bus voltage. It is composed of a pulsewidth modulation (PWM) rectifier directly tied to the generator's terminals without ac reactors. Hence terminal voltages are not useful due to the switched pulse of the PWM rectifier and also it is not the

Hyunjae Yoo; Jang-Hwan Kim; Seung-Ki Sul

2007-01-01

333

Space vehicle electrical power processing distribution and control study. Volume 1: Summary  

NASA Technical Reports Server (NTRS)

A concept for the processing, distribution, and control of electric power for manned space vehicles and future aircraft is presented. Emphasis is placed on the requirements of the space station and space shuttle configurations. The systems involved are referred to as the processing distribution and control system (PDCS), electrical power system (EPS), and electric power generation system (EPGS).

Krausz, A.

1972-01-01

334

An approach to determine Distributed Generation (DG) benefits in power networks  

Microsoft Academic Search

In this paper, an approach to determine the value-added benefits of distributed generation (DGs) on the performance of power system is proposed. It utilizes a robust optimization technique to compute marginal price contributions of distributed generation (DGs) in a typical power system network. An approach that is based on optimal power flow has been shown. It also features incorporating DG

James A. Momoh; Yan Xia; Garfield D. Boswell

2008-01-01

335

Transient stability evaluation of power systems with large amounts of distributed generation  

Microsoft Academic Search

It is expected that increasing amount of distributed generation (DG) will be connected to electrical power systems in the near future. When these generations are in small amounts, their impacts on power system dynamics will be negligible. But if the penetration level becomes higher, distributed generations may start to influence the dynamic behavior of a power system as a whole

A. Khosravi; M. Jazaeri; S. A. Mousavi

2010-01-01

336

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

337

Power Quality of Distributed Wind Projects in the Turbine Verification Program  

SciTech Connect

The Electric Power Research Institute/U.S. Department of Energy (EPRI/DOE) Turbine Verification Program (TVP) includes four distributed wind generation projects connected to utility distribution feeders located in Algona, Iowa; Springview, Nebraska; Glenmore, Wisconsin; and Kotzebue, Alaska. The TVP has undertaken power quality measurements at each project to assess the impact that power quality has on the local utility grids. The measurements and analysis were guided by the draft IEC 61400-21 standard for power quality testing of wind turbines. The power quality characteristics measured include maximum power, distribution feeder voltage regulation, reactive power, and harmonics. This paper describes the approach to the measurements, the unique electrical system features of the four projects, and an assessment of measured power quality relative to limits prescribed by standards. It also gives anecdotal stories from each project regarding the impact of power quality on the respective distribution feeders.

Green, J; VandenBosche, J.; Lettenmaier, T.; Randall, G; Wind, T

2001-09-13

338

The need for a distributed algorithm for control of the electrical power infrastructure  

Microsoft Academic Search

The move towards renewable energy and the deregulation of the market changes the infrastructure for power transport and distribution from centralised to distributed. This requires a new algorithm for control of the electrical power infrastructure. This paper describes a possible new algorithm: a distributed, emergent algorithm that provides additional dependability and resilience to failures. The trade-offs of this algorithm, faults

Jan Van de Vyver; Geert Deconinck; Ronnie Belmans

2003-01-01

339

Vulnerability Evaluation of Power System Integrated with Large-scale Distributed Generation  

E-print Network

Vulnerability Evaluation of Power System Integrated with Large-scale Distributed Generation Based is integrated with distributed generation (DG), decentralized generation at distribution level replaces some of the centralized generation at transmission level. DG units are able to improve the reliability of the power system

Bak, Claus Leth

340

DSP-Controlled Power Electronic Interface for Fuel-Cell-Based Distributed Generation  

Microsoft Academic Search

The private power producers are increasing rapidly to meet rising load demand in domestic, commercial, and industrial sectors. In this scenario, the distributed generation systems (DGs) play an important role over fossil fuel generation. Among different distributed generation technologies such as fuel cell, wind power, and solar; the fuel-cell-based distributed generation is becoming more popular due to its high efficiency,

Annamalai Kirubakaran; Shailendra Jain; Rajesh Kumar Nema

2011-01-01

341

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

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

An AC motor drive with power factor control for low cost applications  

Microsoft Academic Search

The front-end rectifier followed by a pulse-width modulated voltage source inverter (PWM-VSI) has been a well-established power converter configuration for many industrial drives. The increasing costs on the utility usage, due to power quality regulations, and the need to improve the VA capacity of systems, e.g. off-shore drilling rigs, have increased the interest in the development of power electronic equipment

Maria Dias Bellar

2000-01-01

344

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

345

A Comparison of the AC and DC Power Flow Models for LMP Calculations  

E-print Network

larger 12,965 bus model of the Midwest U.S. transmission grid. Results are provided comparing both of balanced, three phase, electric power transmission networks is through the solution of the power flow. From determine the correct values for large number of discrete and/or limited automatic controls. These controls

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

Wind Power Forecasting Error Distributions over Multiple Timescales: Preprint  

SciTech Connect

In this paper, we examine the shape of the persistence model error distribution for ten different wind plants in the ERCOT system over multiple timescales. Comparisons are made between the experimental distribution shape and that of the normal distribution.

Hodge, B. M.; Milligan, M.

2011-03-01

348

Submodule Integrated Distributed Maximum Power Point Tracking for Solar Photovoltaic Applications  

E-print Network

This paper explores the benefits of distributed power electronics in solar photovoltaic applications through the use of submodule integrated maximum power point trackers (MPPT). We propose a system architecture that provides ...

Pilawa-Podgurski, Robert C. N.

349

Distribution of MdACS3 null alleles in apple (Malus × domestica Borkh.) and its relevance to the fruit ripening characters  

PubMed Central

Expression of MdACS3a, one of the ripening-related ACC synthase genes, plays a pivotal role in initiating the burst of ethylene production by MdACS1 in apple fruit. Although previous studies have demonstrated the presence of MdACS3a-null alleles through deficiency of transcription activity or loss of enzyme activity due to amino acid substitution, which may affect the storage properties of certain fruit cultivars, an overall picture of these null alleles in cultivars is still lacking. The present study investigated the distribution of null allelic genes in 103 cultivars and 172 breeding selections by using a simple sequence repeat (SSR) marker linked to them. The results indicated that both allelic genes were widely distributed throughout the examined cultivars and selections, some occurring as the null genotype, either homozygously or heterozygously, with each null allele. The implications of MdACS3a distribution results and the influence of its null allelotypes in fruit characters are discussed. PMID:23136513

Bai, Songling; Wang, Aide; Igarashi, Megumi; Kon, Tomoyuki; Fukasawa-Akada, Tomoko; Li, Tianzhong; Harada, Takeo; Hatsuyama, Yoshimichi

2012-01-01

350

Effect of stroke rate on the distribution of net mechanical power in rowing  

Microsoft Academic Search

The aim of this study was to assess the effect of manipulating stroke rate on the distribution of mechanical power in rowing. Two causes of inefficient mechanical energy expenditure were identified in rowing. The ratio between power not lost at the blades and generated mechanical power () and the ratio between power not lost to velocity fluctuations and were used

Mathijs J. Hofmijster; Erik H. J. Landman; Richard M. Smith

2007-01-01

351

Power Management Strategies for a Microgrid With Multiple Distributed Generation Units  

Microsoft Academic Search

This paper addresses real and reactive power management strategies of electronically interfaced distributed generation (DG) units in the context of a multiple-DG microgrid system. The emphasis is primarily on electronically interfaced DG (EI-DG) units. DG controls and power management strategies are based on locally measured signals without communications. Based on the reactive power controls adopted, three power management strategies are

F. Katiraei; M. R. Iravani

2006-01-01

352

Fuzzy system control for combined wind and solar power distributed generation unit  

Microsoft Academic Search

For renewable energy generation in the distributed and co-generation (DCG) scheme, photovoltaics and wind power are already in service at many installations. Basically, these types of energy generation are very favourable for the environment but do not produce power on customers load demands, have long intervals of lacking power generation due to absence of power input (no sunshine, no wind),

Helmut WEISS; Jian Xiao

2003-01-01

353

Transient polarity comparison based protection for system with power electronic interfaced distributed generation units  

Microsoft Academic Search

Various distributed generation units (DGs) are connected to utility power grid. With the advances in power electronics technology, many electronics converter interfaces have been utilized in DGs. The power balance control strategies can be achieved by the flexible control modes of the power electronics converter. However, because of the dynamic response and adjustment ability of the electronics converter interface, the

Wei Kong; Z. Chen; Z. Q. Bo; X. Z. Dong; A. Klimek

2007-01-01

354

Load Balancing for Distributed and Integrated Power Systems using Grid Computing  

Microsoft Academic Search

The need for renewable power generation in power systems is becoming more importance. This need requires geographically-distributed power systems to be integrated as a single entity where among the main features of this integration are large data base and computing intensive. Grid Computing is a gateway to virtual storage media and processing power, this paper describes how grid computing can

R. Al-Khannak; B. Bitzer

2007-01-01

355

Small inverter-interfaced distributed energy resources for reactive power support  

Microsoft Academic Search

The use of small inverter-interfaced distributed energy resources for reactive power support is discussed. While the primary function of these resources is to deliver active power, they can also be used to provide reactive power, often identified as an ancillary service by a utility. Given the large and increasing number of small grid-connected inverters, the total reactive power that can

Alejandro D. Dominguez-Garcia; Christoforos N. Hadjicostis; Philip T. Krein; Stanton T. Cady

2011-01-01

356

An Integrated Hybrid Power Supply for Distributed Generation Applications Fed by Nonconventional Energy Sources  

Microsoft Academic Search

A new, hybrid integrated topology, fed by photovoltaic (PV) and fuel cell (FC) sources and suitable for distributed generation applications, is proposed. It works as an uninterruptible power source that is able to feed a certain minimum amount of power into the grid under all conditions. PV is used as the primary source of power operating near maximum power point

Sachin Jain; Vivek Agarwal

2008-01-01

357

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

358

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

359

A power regulator for the generators on the A.C. network calculator  

E-print Network

is the detector. The power output of the unit must be accurately measured in order to detect any variations. Many devices will accomplish this purpose. At the be- ginning of this investigation the detectors under consideration were: 1. watt-hour meter 2...- tween the output and the actual power measured 2. freedom from affects of extraneous variables - its accuracy must not be affected by such things as power factor 3. sensitivity 4. require little maintenance 5. low cost The watt-hour meter is a...

Francis, Lawrence Gregg

1956-01-01

360

Status of 20 kHz space station power distribution technology  

NASA Technical Reports Server (NTRS)

Power Distribution on the NASA Space Station will be accomplished by a 20 kHz sinusoidal, 440 VRMS, single phase system. In order to minimize both system complexity and the total power coversion steps required, high frequency power will be distributed end-to-end in the system. To support the final design of flight power system hardware, advanced development and demonstrations have been made on key system technologies and components. The current status of this program is discussed.

Hansen, Irving G.

1988-01-01

361

Powerful Cherenkov oscillators with 2D distributed feedback  

NASA Astrophysics Data System (ADS)

The feasibility of using 2D distributed feedback based on 2D planar and coaxial Bragg structures for generating spatially coherent radiation from rectilinear ribbon and tubular electron beams is studied. One-section and sectional Cherenkov masers are analyzed. In the former design, a 2D Bragg structure acts as a resonator and a periodic slow-wave system simultaneously. In the latter (sectional) design, radiation is synchronized in a 2D Bragg structure that is placed at the cathode end of the interaction space and couples longitudinal and transverse (azimuthal) wave flows. The wave is amplified by the electron beam mainly in the fairly long middle section. The output (collector) part contains a standard 1D Bragg structure that partially reflects the amplified radiation toward the cathode and closes the feedback circuit. It is shown that dissipation introduced into the 2D Bragg structure of the sectional design makes it possible to increase one of the transverse sizes of the system to ˜103 wavelengths with the energy exchange efficiency and one-frequency masing mode stability remaining the same. With such an overdimension, the millimeter-wave radiation integral power may reach a gigawatt level.

Ginzburg, N. S.; Zaslavskii, V. Yu.; Ilyakov, E. V.; Kulagin, I. S.; Malkin, A. M.; Peskov, N. Yu.; Sergeev, A. S.

2011-12-01

362

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

363

Network-integrated stability enhancement strategy for power system with distributed generations  

Microsoft Academic Search

This paper proposes a new computer network-integrated stability enhancement strategy for electricity power system connected with renewable-energy distributed generations. The proposed strategy aims to save a distribution system from imminent voltage collapse due to contingencies occurring in the subtransmission network, distribution network, or distributed generation circuit, by executing appropriate operations. The operations include coordinated generator controls, load tap changing, load

Lin Wang; Helen Cheung; Alexander Hamlyn; Richard Cheung

2008-01-01

364

An AC motor drive with power factor control for low cost applications  

Microsoft Academic Search

In this work, a new concept of integrating motor and power factor controls, by using a single-phase to three-phase DSP based six-switch converter topology, is presented. Unlike other configurations which use extra switch(es) and\\/or extra boost inductor, in the proposed topology the boost action, for input current shaping, is done by the motor leakage inductances. The power factor control and

M. D. Bellar; B. K. Lee; B. Fahimi; M. Ehsani

2001-01-01

365

Electrochemical characterization and modeling of fuel cells via AC impedance and residence time distribution  

Microsoft Academic Search

The performance of commercially available fuel cells was tested under a variety of test conditions and models were formulated to explain the experimental results. Several techniques were applied to single cells and groups of cells, each probing a different phenomenon responsible for limiting the power output of the cells. Nonuiformity of fuel cells in a stack can drastically affect the

Robert R. U. Payne

2008-01-01

366

Distributed solid state programmable thermostat/power controller  

NASA Technical Reports Server (NTRS)

A self-contained power controller having a power driver switch, programmable controller, communication port, and environmental parameter measuring device coupled to a controllable device. The self-contained power controller needs only a single voltage source to power discrete devices, analog devices, and the controlled device. The programmable controller has a run mode which, when selected, upon the occurrence of a trigger event changes the state of a power driver switch and wherein the power driver switch is maintained by the programmable controller at the same state until the occurrence of a second event.

Alexander, Jane C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

2008-01-01

367

Distribution of the traction return current in AC and DC electric railway systems  

Microsoft Academic Search

The problem of the determination of the real distribution of the return current in electric railway traction systems is considered. One or more conductors (depending on the specific supply system) are purposely set up to carry the traction return current flowing from the rolling stock axles back to the supply (i.e., substation); yet, part of the return current flows through

Andrea Mariscotti

2003-01-01

368

Fish method: Interaction between AC-machines and switching power converters  

NASA Astrophysics Data System (ADS)

When studying the complex interaction between AC-machines and converters, proper simulation models are necessary. This thesis is devoted to a new viewpoint on this complex matter: the Fish Method. Based on a seemingly reckless simplification of the machine model, the fish method provides a simple approximate mathematical description between switching pattern and stator current in terms of flux. A coordinate transformation of the stator flux orbit renders a graph that can be seen as a unique switching pattern's signature: the flux-fish. The transformed current orbit of almost the same shape is called the current-fish. Some size-related flux-fish characteristics are incorporated into a generally applicable quality criterion, independent of machine parameters, enabling straightforward switching pattern comparison. The performance of any switching converter that operates at a fixed frequency output can be evaluated in a graphical and numerical way by means of transforming the terminal voltages into a flux fish. At a single glance, the graphical flux fish shows a lot of information to the trained eye.

Veltman, A.

1994-01-01

369

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

370

Lightning protection of 1000 kV AC power transmission lines and substations  

Microsoft Academic Search

First of all, in combination with characteristics of the lightning performance of UHV power transmission lines and on the basis of the analysis of experiences and lessons concerning excessively high lightning trip-out rate on 1000 kV transmission lines in Japan and the former Soviet Union, authors of this paper put forward that one of the critical points in the key

Gu Dingxie; Dai Min; He Huiwen

2011-01-01

371

An Analog Computer Study of a Parallel AC and DC Power System  

Microsoft Academic Search

Overall critical evaluation of the dynamics of EHV dc-power transmission requires that a variety of system conditions and effects of many parameters be studied. Problems can be strictly electrical or electromechanical. In general, those that fall in the former category are of short time duration, while those in the latter may be either of intermediate duration, on the order of

H. A. Peterson; P. C. Jr. Krause; J. F. Luini; C. H. Thomas

1966-01-01

372

Calculated effect of central DC\\/AC power conversion from PV generators with different orientations  

Microsoft Academic Search

The energy production of two PV\\/inverter configurations for a grid-connected PV power system consisting of roof and facade integrated subarrays with five different orientations and tilt angles was predicted by computer simulations. These calculations show that the total DC energy production of the system is practically not affected if the subarrays have one central inverter and all operate at the

T. C. J. van der Weiden; A. J. Kil

1994-01-01

373

New approaches to provide ride-through for critical loads in electric power distribution systems  

NASA Astrophysics Data System (ADS)

The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly-phase voltage sags. Algorithms capable of detecting voltage disturbances such as voltage sags, voltage swells, flicker, frequency change, and harmonics in a fast and reliable way are investigated and developed in this dissertation as an essential part of the approaches previously described. Simulation and experimental work has been done to validate the feasibility of all approaches under the most common voltage disturbances such as single-phase voltage sags and three-phase voltage sags.

Montero-Hernandez, Oscar C.

2001-07-01

374

Feasibility study of a 270V dc flat cable aircraft electrical power distributed system  

Microsoft Academic Search

This report documents the efforts of a one man-year feasibility study to evaluate the usage of flat conductors in place of conventional round wires for a 270 volt direct current aircraft power distribution system. This study consisted of designing electrically equivalent power distribution harnesses in flat conductor configurations for a currently operational military aircraft. Harness designs were established for installation

M. J. Musga; R. J. Rinehart

1982-01-01

375

Battery Energy Storage for Enabling Integration of Distributed Solar Power Generation  

Microsoft Academic Search

As solar photovoltaic power generation becomes more commonplace, the inherent intermittency of the solar resource poses one of the great challenges to those who would design and implement the next generation smart grid. Specifically, grid-tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large

Cody A. Hill; Matthew Clayton Such; Dongmei Chen; W. Mack Grady

2012-01-01

376

Integrating distributed generation into electric power systems: A review of drivers, challenges and opportunities  

Microsoft Academic Search

It is now more than a decade since distributed generation (DG) began to excite major interest amongst electric power system planners and operators, energy policy makers and regulators as well as developers. This paper presents an overview of the key issues concerning the integration of distributed generation into electric power systems that are of most interest today. The main drivers

J. A. Peças Lopes; N. Hatziargyriou; J. Mutale; P. Djapic; N. Jenkins

2007-01-01

377

Multilevel current source inverter to improve power quality in a distribution network  

Microsoft Academic Search

This paper deals with the problem of reactive power and harmonics in a standard medium voltage (MV) distribution network. It presents the design of a shunt active filter implemented with a multilevel current source inverter (MCSI) connected to the medium voltage level of a power distribution system. The proposed MCSI is made by identical modules where all inductors carry the

Miguel Aguirre; Laura Calviño; V. Fabián Corasaniti; María Inés Valla

2010-01-01

378

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

379

Impacts of Distributed Generators on the Oscillatory Stability of Interconnected Power Systems  

Microsoft Academic Search

Integration of distributed generation is continually and gradually aecting the stability of intercon- nected power systems. In this paper, the impacts of distributed synchronous generators on oscillatory stability are studied. In various parameter sub-spaces of interest, feasibility regions can be calculated to determine the conditions to sustain the stable operation of an interconnected power system. Through com- putations of the

Istemihan GENC; Omer USTA

2005-01-01

380

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

381

Integration of distributed generation in the networks of Latvian power system  

Microsoft Academic Search

Distributed (dispersed) generation (DG) entities are private and operated independently upon the main grid in Latvia. In the paper the impact of connected DG to the distribution network is analysed in regard to network operation modes and network operation parameters: voltage losses, power flows and overflows, energy losses per year etc. As research objects private electric power plants have been

Z. Krishans; A. Mutule; A. Kutjuns

2005-01-01

382

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

Microsoft Academic Search

For extensive utilization of distributed generation with the objectives of more efficient use of energy and introduction of renewable energy sources, the construction of a micro grid at demand end is inevitable. The micro grid should operate independently and have a good neighbor relation with the power grid, which supplies base power to it. A coordinate control scheme of distributed

S. Kusagawa; E. Masada; J. Baba; M. Ohshima; I. Nagy

2005-01-01

383

On-Line Stability Control of Power Systems Integrated with Distributed Generation Systems  

Microsoft Academic Search

Because of the certain stochastic nature of renewable generation, large-scale distributed generation systems can impose unpredictable impact on the stability of their integrated transmission systems. This paper demonstrates that power system oscillations can be caused by unpredictable changes of operating conditions of integrated distributed generation systems and hence presents a novel method of power system damping control by applying the

X. Jin; J. Zhao; H. F. Wang

2006-01-01

384

Impact of distributed generation on the stability of electrical power system  

Microsoft Academic Search

This paper aims at analysing the potential impacts that distributed generation might have on the stability of electrical power networks. In particular, the performance of a power system with significant penetration of distributed resources is described to assess different types of stability of the bulk network. For this purpose, a hypothetical network is simulated, assuming a large number of fuel

Ahmed M. Azmy; István Erlich

2005-01-01

385

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

386

A novel integrated AC choke for common-mode voltage suppression in power converter systems  

Microsoft Academic Search

This paper presents a novel three-phase choke that integrates the common-mode (CM) suppression and differential- mode (DM) filtering functions. The proposed choke provides a transformerless solution to issues caused by the switching common-mode voltage (CMV) in power converter systems. The magnetic core involves three bridge legs and a peripheral part on which one set (three-phase) of coils are wound. While

Ning Zhu; Jinsong Kang; Dewei Xu; Bin Wu; Yuan Xiao

2011-01-01

387

Power Quality of Distributed Wind Projects in the Turbine Verification Program  

Microsoft Academic Search

The Electric Power Research Institute\\/U.S. Department of Energy (EPRI\\/DOE) Turbine Verification Program (TVP) includes four distributed wind generation projects connected to utility distribution feeders located in Algona, Iowa; Springview, Nebraska; Glenmore, Wisconsin; and Kotzebue, Alaska. The TVP has undertaken power quality measurements at each project to assess the impact that power quality has on the local utility grids. The measurements

J Green; J. VandenBosche; T. Lettenmaier; G Randall; T Wind

2001-01-01

388

HA2TSD: hierarchical time slack distribution for ultra-low power CMOS VLSI  

Microsoft Academic Search

This paper describes an efficient hierarchical design and optimization approach for ultra-low power CMOS logic circuits. We introduce the Hierarchical Activity-Aware Time Slack Distribution (HA2TSD) algorithm, which distributes the surplus time slack into the most power-hungry modules hierarchically. HA2TSD ensures that the total slack budget is maximal and the total power is near-minimal. Based on these time slacks, we have

Kyu-won Choi; Abhijit Chatterjee

2002-01-01

389

HA 2 TSD: hierarchical time slack distribution for ultra-low power CMOS VLSI  

Microsoft Academic Search

This paper describes an efficient hierarchical design and optimization approach for ultra-low power CMOS logic circuits. We introduce the Hierarchical Activity-Aware Time Slack Distribution (HA2TSD) algorithm, which distributes the surplus time slack into the most power-hungry modules hierarchically. HA2TSD ensures that the total slack budget is maximal and the total power is near-minimal. Based on these time slacks, we have

Kyu-won Choi; Abhijit Chatterjee

2002-01-01

390

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

391

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 to the function generator and the load resistance to the load coils. II. MAGNETIC RESONANT POWER DELIVERY, Pittsburgh, PA 15213 Abstract-- In this paper we report on a resonant wireless power delivery system using

Cervesato, Iliano

392

Active Islanding Detection for Inverter-Based Distributed Generation Systems With Power Control Interface  

Microsoft Academic Search

Conventional active islanding detection methods (IDMs) are designed for the inverter-based distributed gen- eration systems (DGSs) with current control interface. Such strategies can hardly be extended to the DGS with power con- trol interface because the power control loop can affect the IDMs by enlarging the nondetection zones (NDZs). This paper presents an active IDM based on negative-sequence power injections

Hua Geng; Bin Wu; Geng Yang

2011-01-01

393

Limited-Feedback-Based Channel-Aware Power Allocation for Linear Distributed Estimation  

E-print Network

Limited-Feedback-Based Channel-Aware Power Allocation for Linear Distributed Estimation Mohammad observations, the study of the allo- cation of transmit power to the sensors becomes important. Most optimal power-allocation schemes in the literature require the feedback of the exact instantaneous channel state

Valenti, Matthew C.

394

A distributed scheme for integrated predictive dynamic channel and power allocation in cellular radio networks  

Microsoft Academic Search

We propose a distributed dynamic channel and power allocation (DCPA) scheme based on a novel predictive power control algorithm. The minimum interference dynamic channel assignment algorithm is employed, while simple Kalman filters are designed to provide the predicted measurements of both the channel gains and the interference levels, which are then used to update the power levels. Extensive computer simulations

Kambiz Shoarinejad; Jason L. Speyer; Gregory J. Pottie

2001-01-01

395

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

396

A Generalized Iterative Water-filling Algorithm for Distributed Power Control in the Presence  

E-print Network

1 A Generalized Iterative Water-filling Algorithm for Distributed Power Control in the Presence iterative water-filling algorithm whereby the users and the jammer update their power allocations and a jammer share a common spectrum of N orthogonal tones. Both the users and the jammer have limited power

Luo, Zhi-Quan "Tom"

397

Analysis of PI and PR controllers for distributed power generation system under unbalanced grid faults  

Microsoft Academic Search

It is the general trend to increase the electricity production using distributed power system (DPGS), which is based on renewable energy sources such as wind, solar, fuel cell etc. These systems are to be properly controlled in order to provide reliable power to the utility network. For that power electronics converters are used as an interfacing device between DPGS and

Ashish Ranjan Dash; B. Chitti Babu; K. B. Mohanty; Rahul Dubey

2011-01-01

398

Transport coefficients in Lorentz plasmas with the power-law kappa-distribution  

SciTech Connect

Transport coefficients in Lorentz plasma with the power-law ?-distribution are studied by means of using the transport equation and macroscopic laws of Lorentz plasma without magnetic field. Expressions of electric conductivity, thermoelectric coefficient, and thermal conductivity for the power-law ?-distribution are accurately derived. It is shown that these transport coefficients are significantly modified by the ?-parameter, and in the limit of the parameter ??? they are reduced to the standard forms for a Maxwellian distribution.

Jiulin, Du [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China)] [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China)

2013-09-15

399

The MLP Distribution: A Modified Lognormal Power-Law Model for the Stellar Initial Mass Function  

E-print Network

This work explores the mathematical properties of a distribution introduced by Basu & Jones (2004), and applies it to model the stellar initial mass function (IMF). The distribution arises simply from an initial lognormal distribution, requiring that each object in it subsequently undergoes exponential growth but with an exponential distribution of growth lifetimes. This leads to a modified lognormal with a power-law tail (MLP) distribution, which can in fact be applied to a wide range of fields where distributions are observed to have a lognormal-like body and a power-law tail. We derive important properties of the MLP distribution, like the cumulative distribution, the mean, variance, arbitrary raw moments, and a random number generator. These analytic properties of the distribution can be used to facilitate application to modeling the IMF. We demonstrate how the MLP function provides an excellent fit to the IMF compiled by Chabrier (2005) and how this fit can be used to quickly identify quantities like...

Basu, Shantanu; Auddy, Sayantan

2015-01-01

400

Distributed Energy Resources, Power Quality and Reliability - Background  

SciTech Connect

Power quality [PQ] and power reliability [PR] gained importance in the industrialized world as the pace of installation of sensitive appliances and other electrical loads by utility customers accelerated, beginning in the mid 1980s. Utility-grid-connected customers rapidly discovered that this equipment was increasingly sensitive to various abnormalities in the electricity supply.

Schienbein, Lawrence A.; DeSteese, John G.

2002-01-31

401

Power system management and distribution for future spacecraft  

Microsoft Academic Search

Spacecraft power requirements have grown throughout the last years from 0.6 Kw to 20 Kw for communication and sensor spacecraft and up-to 100 Kw for space platforms such as Space Station Freedom. This growth in power was due to the increase in services supplied by present spacecraft and the increase in complexity of future space systems which are linked to

Hassan M. Yousef

1991-01-01

402

Distributed computing power : from local function to global computing  

Microsoft Academic Search

We show here a natural extension of finite graph automata, by allowing each node of a network to store in its memory some pieces of information that are only bounded by the size of the underlying network (like a unique address). Depending of the power of the new local tran- sition function, we show results about the power of the

Laurent Bienvenu; Christophe Papazian

403

Impact of electric vehicles on power distribution networks  

Microsoft Academic Search

The market for battery powered and plug-in hybrid electric vehicles is currently limited, but this is expected to grow rapidly with the increased concern about the environment and advances in technology. Due to their high energy capacity, mass deployment of electrical vehicles will have significant impact on power networks. This impact will dictate the design of the electric vehicle interface

G. A. Putrus; P. Suwanapingkarl; D. Johnston; E. C. Bentley; M. Narayana

2009-01-01

404

High voltage-high power components for large space power distribution systems  

NASA Technical Reports Server (NTRS)

Space power components including a family of bipolar power switching transistors, fast switching power diodes, heat pipe cooled high frequency transformers and inductors, high frequency conduction cooled transformers, high power-high frequency capacitors, remote power controllers and rotary power transfer devices were developed. Many of these components such as the power switching transistors, power diodes and the high frequency capacitor are commercially available. All the other components were developed to the prototype level. The dc/dc series resonant converters were built to the 25 kW level.

Renz, D. D.

1984-01-01

405

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

406

Voltage Stability and Frequency Synchronization of Weak Power Distribution Networks with Inverter-Based  

E-print Network

Voltage Stability and Frequency Synchronization of Weak Power Distribution Networks with Inverter not apply to truly weak networks. Key words: Weak networks, inverter-based distributed generator, voltage and frequency stability. 1 INTRODUCTION Inverter-based distributed generation (DG) sources are usually a part

Lemmon, Michael

407

Distributed Intelligence: Extending the Power of the Unaided, Individual Human Mind  

E-print Network

Distributed Intelligence: Extending the Power of the Unaided, Individual Human Mind Gerhard Fischer surroundings in which cognition and human activity take place. Distributed intelligence provides an effective-technical environments supporting distributed intelligence. Categories and Subject Descriptors H.5.3 Group

Fischer, Gerhard

408

Planning with MIP for Supply Restoration in Power Distribution Systems Sylvie Thiebaux1  

E-print Network

Planning with MIP for Supply Restoration in Power Distribution Systems Sylvie Thi´ebaux1 , Carleton. This is especially acute in distribution systems, where re- newable integration often occurs. This paper in in the operation of distribution systems. PSR consists in generating a sequence of switching operations

Thiébaux, Sylvie

409

Simulation of a Lunar Surface Base Power Distribution Network for the Constellation Lunar Surface Systems  

NASA Technical Reports Server (NTRS)

The Lunar Surface Power Distribution Network Study team worked to define, breadboard, build and test an electrical power distribution system consistent with NASA's goal of providing electrical power to sustain life and power equipment used to explore the lunar surface. A testbed was set up to simulate the connection of different power sources and loads together to form a mini-grid and gain an understanding of how the power systems would interact. Within the power distribution scheme, each power source contributes to the grid in an independent manner without communication among the power sources and without a master-slave scenario. The grid consisted of four separate power sources and the accompanying power conditioning equipment. Overall system design and testing was performed. The tests were performed to observe the output and interaction of the different power sources as some sources are added and others are removed from the grid connection. The loads on the system were also varied from no load to maximum load to observe the power source interactions.

Mintz, Toby; Maslowski, Edward A.; Colozza, Anthony; McFarland, Willard; Prokopius, Kevin P.; George, Patrick J.; Hussey, Sam W.

2010-01-01

410

An AC processing pickup for IPT systems  

Microsoft Academic Search

This paper presents a new type of Inductive Power Transfer (IPT) pickup which directly regulates power in AC form, hence producing a controllable high-frequency AC source. The pickup has significant advantages in terms of increasing system efficiency, reducing pickup size and lowering production cost compared to traditional pickups that also produce a controlled AC output using complex AC-DC-AC conversion circuits.

Hunter Hanzhuo Wu; J. Boys; G. Covic; Saining Ren; P. Hu

2009-01-01

411

Distributed generation system based on single-phase grid, induction generator and solar photovoltaic panel  

Microsoft Academic Search

This paper studies a distributed generation electrical system. It is composed of an induction generator with a prime mover, a single-phase utility grid and a solar panel. All energy sources are connected by using a reduced switch count AC-AC converters. A hydraulic power or an other power controlled source is adopted to drive the induction generator, operating as a prime

E. C. dos Santos; C. B. Jacobina; M. B. R. Correa; N. Rocha

2008-01-01

412

Design and analysis of power distribution networks in PowerPC microprocessors  

Microsoft Academic Search

We present a methodology for the design and analysis of power grids in the PowerPC#8482; microprocessors. The methodology covers the need for power grid analysis across all stages of the design process. A case study showing the application of this methodology to the PowerPC#8482; 750 microprocessor is presented.

Abhijit Dharchoudhury; Rajendran Panda; David Blaauw; Ravi Vaidyanathan; Bogdan Tutuianu; David Bearden

1998-01-01

413

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

414

Space power distribution system technology. Volume 3: Test facility design  

NASA Technical Reports Server (NTRS)

The AMPS test facility is a major tool in the attainment of more economical space power. The ultimate goals of the test facility, its primary functional requirements and conceptual design, and the major equipment it contains are discussed.

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

1983-01-01

415

Power systems analysis for direct current (dc) distribution systems  

SciTech Connect

Many standards, guidelines, etc., currently exist which provide guidance for dc power systems analysis. These documents are scattered throughout the industry (i.e., IEEE, UL, NEMA, GE, etc.), and primarily treat the subject as though hand calculations are being performed. It is the intent of this paper to provide guidance for performing computer aided dc power systems analyzes. This paper will cover load flow/voltage drop and short circuit calculations.

Fleischer, K. [Public Service Electric and Gas, Hancock`s Bridge, NJ (United States). Salem Nuclear Generating Station] [Public Service Electric and Gas, Hancock`s Bridge, NJ (United States). Salem Nuclear Generating Station; Munnings, R.S. [VECTRA Technologies, Inc., Lincolnshire, IL (United States)] [VECTRA Technologies, Inc., Lincolnshire, IL (United States)

1996-09-01

416

Distributed and coupled electrothermal model of power semiconductor devices  

Microsoft Academic Search

Electro-thermal model of power semiconductor devices are of key importance in order to optimize their thermal design and increase their reliability. The development of such an electro-thermal model for power MOSFET transistors (COOLMOS™) based on the coupling between two computation softwares (Matlab and Cast3M) is described in the paper. The elaborated 2D electro-thermal model is able to predict i) the

G. Belkacem; D. Labrousse; S. Lefebvre; P-Y Joubert; U. Kuhne; L. Fribourg; R. Soulat; E. Florentin; C. Rey

2012-01-01

417

Unified power quality conditioner for distribution system without reference calculations  

Microsoft Academic Search

Power quality is an important measure of the performance of electric power system. The main concerns include voltage quality and the current quality. The voltage may contain amplitude errors, harmonics, phase unbalance, sag\\/dips, swells, flicks, impulses and interrupt\\/outage. As for the current quality is concerned, harmonics, reactive component, unbalance, excessive neutral\\/zero-sequence current are the main issues. This paper proposes a

Guozhu Chen; Yang Chen; Luis Felipe Sanchez; Keyue M. Smedley

2004-01-01

418

Power-Demand Routing in massive geo-distributed systems  

E-print Network

There is an increasing trend toward massive, geographically distributed systems. The largest Internet companies operate hundreds of thousands of servers in multiple geographic locations, and are growing at a fast clip. A ...

Qureshi, Asfandyar

2010-01-01

419

Distributed generation technology in a newly competitive electric power industry  

SciTech Connect

The electric utility industry is in the midst of enormous changes in market structure. While the generation sector faces increasing competition, the utilities` transmission and distribution function is undergoing a transition to more unbundled services and prices. This article discusses the extent to which these changes will affect the relative advantage of distributed generation technology. Although the ultimate market potential for distributed generation may be significant, the authors find that the market will be very heterogeneous with many small and only a few medium-sized market segments narrowly defined by operating requirements. The largest market segment is likely to develop for distributed generation technology with operational and economical characteristics suitable for peak-shaving. Unbundling of utility costs and prices will make base- and intermediate-load equipment, such as fuel cells, significantly less attractive in main market segments unless capital costs fall significantly below $1,000/kW.

Pfeifenberger, J.P.; Ammann, P.R.; Taylor, G.A. [Brattle Group, Cambridge, MA (United States)

1996-10-01

420

Ag incorporated Mn3O4/AC nanocomposite based supercapacitor devices with high energy density and power density.  

PubMed

Silver incorporated Mn3O4/amorphous carbon (AC) nanocomposites are synthesized by a green chemistry method. X-ray diffraction studies revealed the structural changes in Mn3O4/AC nanocomposites attributable to the addition of silver. Cyclic voltammetry, charge-discharge and ac-impedance studies indicated that the Ag-Mn3O4/AC-5 electrode was the most suitable candidate for supercapacitor applications. From the galvanostatic charge-discharge studies, a higher specific capacitance of 981 F g(-1) at a specific current of 1 A g(-1) was obtained. An Ag-Mn3O4/AC-symmetric supercapacitor consisting of an Ag-incorporated Mn3O4/AC composite as an anode as well as a cathode, and an asymmetric supercapacitor consisting of an Ag-incorporated Mn3O4/AC composite as a cathode and an activated carbon as an anode have been fabricated. The symmetric device exhibits a specific cell capacitance of 72 F g(-1) at a specific current of 1 A g(-1) whereas the asymmetric device delivers a specific cell capacitance of 180 F g(-1) at a high current rate of 10 A g(-1). The asymmetric supercapacitor device yields a high energy density of 81 W h kg(-1). This is higher than that of lead acid batteries and comparable with that of nickel hydride batteries. PMID:25347031

Nagamuthu, S; Vijayakumar, S; Muralidharan, G

2014-12-14

421

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

422

Research on Super Capacitor Energy Storage System for Power Network  

Microsoft Academic Search

A Super Capacitor Energy Storage (SCES) system applied to distributed generation system and distribution network is presented, which is mainly composed of three parts: the electrical double-layer capacitors array that stores energy, the AC\\/DC-DC\\/AC power converter system and the integrated control system composed of microprocessors. Application studies of the SCES system for active power supply, voltage control, voltage oscillation elimination

Jiancheng Zhang

2005-01-01

423

Distributed Processing System for Restoration of Electric Power Distribution Network Using Two-Layered Contract Net Protocol  

NASA Astrophysics Data System (ADS)

Distributed processing system for restoration of electric power distribution network using two-layered CNP is proposed. The goal of this study is to develop the restoration system which adjusts to the future power network with distributed generators. The state of the art of this study is that the two-layered CNP is applied for the distributed computing environment in practical use. The two-layered CNP has two classes of agents, named field agent and operating agent in the network. In order to avoid conflicts of tasks, operating agent controls privilege for managers to send the task announcement messages in CNP. This technique realizes the coordination between agents which work asynchronously in parallel with others. Moreover, this study implements the distributed processing system using a de-fact standard multi-agent framework, JADE(Java Agent DEvelopment framework). This study conducts the simulation experiments of power distribution network restoration and compares the proposed system with the previous system. We confirmed the results show effectiveness of the proposed system.

Kodama, Yu; Hamagami, Tomoki

424

Modelling and Computation of AC Fields and Losses in  

E-print Network

is a crucial factor for any future power applications, and needs exploring. High Temperature Superconductors and efficient HTS step-down transformers will be used by distribution utilities. Environmentally friendlyModelling and Computation of AC Fields and Losses in High Temperature Superconductors Principal

Sóbester, András

425

A Bayesian test for excess zeros in a zero-inflated power series distribution  

E-print Network

Power series distributions form a useful subclass of one-parameter discrete exponential families suitable for modeling count data. A zero-inflated power series distribution is a mixture of a power series distribution and a degenerate distribution at zero, with a mixing probability $p$ for the degenerate distribution. This distribution is useful for modeling count data that may have extra zeros. One question is whether the mixture model can be reduced to the power series portion, corresponding to $p=0$, or whether there are so many zeros in the data that zero inflation relative to the pure power series distribution must be included in the model i.e., $p\\geq0$. The problem is difficult partially because $p=0$ is a boundary point. Here, we present a Bayesian test for this problem based on recognizing that the parameter space can be expanded to allow $p$ to be negative. Negative values of $p$ are inconsistent with the interpretation of $p$ as a mixing probability, however, they index distributions that are physic...

Bhattacharya, Archan; Datta, Gauri S

2008-01-01

426

Multiple voltage electrical power distribution system for automotive applications  

Microsoft Academic Search

Over the course of the 20th Century, the automobile electrical system has experienced one architectural change, one significant electrical power plant change and one notable change in the electrical storage component. There is now growing disparity in voltage level requirements between electronic and electrical loads to the point that a single voltage system may no longer be the most efficient

John M. Miller

1996-01-01

427

Topic 5: Renewable Power 1Networking and Distributed Systems  

E-print Network

-Rad Texas Tech UniversityCommunications and Control in Smart Grid 4 · Annual greenhouse gas emissions UniversityCommunications and Control in Smart Grid · Carbon Footprint is usually defined as: · Usually in Smart Grid 3 · We are interested in power plants with low carbon footprint: · Both CO2 and CH4

Mohsenian-Rad, Hamed

428

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

429

Distribution of infrared light power for indoor broadband wireless communications  

Microsoft Academic Search

There has been a growing interest in using infrared light for broadband indoor wireless communications. There are two major limitations for establishing a wideband infrared communications link. The first and most important limit is the power requirements of such a link. The second important impairment is the intersymbol interference caused by multipath dispersion. We address the issue of designing an

M. R. Pakravan; M. Kavehrad

1995-01-01

430

Assessing the power law distribution of TGFs Andrew B. Collier,1,2,3  

E-print Network

field required for RREA is appreciably smaller than that for conventional dielectric breakdown. While with a power law model for the distribution of TGF intensities. Finally it was found that the matched TGFs were

Bergen, Universitetet i

431

Design Concepts for Power Distribution Equipment Serving Non-Linear Loads  

E-print Network

This paper explores the effects of power system harmonics induced by non-sinusoidal loads on electrical distribution equipment. The first portion examines the harmonic phenomenon to more fully understand harmonic current behavior from an intuitive...

Massey, G. W.

432

PDA simulator for the power distribution analyses of discharge-excited gaseous media  

NASA Astrophysics Data System (ADS)

Compact programs have been implemented to the information devices of PDA, personal digital assistants, in order to analyze the power distribution of discharge excited gaseous media. The simulation codes are cross-developed between Macintosh computers and PDA.

Takatsu, Yohei; Maekawa, Yoshitaka; Iyoda, Mitsuhiro; Taniwaki, Manabu; Shimizu, Kouki; Sato, Shunichi

2003-11-01

433

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 ...

434

Applying epoch-era analysis for homeowner selection of distributed generation power systems  

E-print Network

The current shift from centralized energy generation to a more distributed model has opened a number of choices for homeowners to provide their own power. While there are a number of systems to purchase, there are no tools ...

Piña, Alexander L

2014-01-01

435

Partial discharge amplitude distribution of power transformer oils  

Microsoft Academic Search

The most commonly used criteria for PDIV (partial-discharge inception voltage) determination are examined using three synthetic transformer oils as test fluids. It is shown that the PD amplitude distribution changes both with increasing applied voltage and with test duration. The use of a multichannel analyzer was shown to be most helpful in rendering the PDIV statistically more meaningful. It is

M. Pompili; C. Mazzetti; R. Schifani

1990-01-01

436

Tailoring modal power distribution in common-core waveguide arrays  

Microsoft Academic Search

In this paper, the scattering matrix method (SMM) is used to analyze the modal properties of evanescently coupled waveguide arrays with cores spaced equidistant from a common central core. Propagation constants and field distributions of the fundamental in-phase supermodes are obtained for waveguide arrays comprising three, four, five, six, and seven cores. The authors show how the coupling strength among

Michael Nguyen; Kenneth Church

2006-01-01

437

A low-power filtering scheme for distributed sensor networks  

Microsoft Academic Search

Because the energy required for communications tasks is much greater than that required for computational tasks, estimation algorithms designed for distributed networks of sensors must attempt to reduce the communications overhead that they require. We suggest a simple mechanism for implementing Luenberger observers that allows estimates to be constructed from transmissions generated at a slower rate than the measurements are

Jonathan D. Wolfe; Jason L. Speyer

2003-01-01

438

On-line test of power distribution prediction system for boiling water reactors  

Microsoft Academic Search

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,

Y. Nishizawa; T. Kiguchi; S. Kobayashi; K. Takumi; H. Tanaka; R. Tsutsumi; M. Yokomi

1982-01-01

439

Power-Aware Design Synthesis Techniques for Distributed Real-Time Systems  

Microsoft Academic Search

This paper presents an end-to-end synthesis technique for low-power distributed real-time system design. This technique synthesizes supply voltages of resources to optimize system-level power consumption while satisfying end-to-end hard real-time latency bounds. A system is modeled as a set of distributed task chains (or pipelines). Each task chain is given its own end-to-end constraints. Task chains may share resources. Our

Dong-In Kang; Stephen Crago; Jinwoo Suh

2001-01-01

440

Application of the mobility power flow approach to structural response from distributed loading  

NASA Technical Reports Server (NTRS)

The problem of the vibration power flow through coupled substructures when one of the substructures is subjected to a distributed load is addressed. In all the work performed thus far, point force excitation was considered. However, in the case of the excitation of an aircraft fuselage, distributed loading on the whole surface of a panel can be as important as the excitation from directly applied forces at defined locations on the structures. Thus using a mobility power flow approach, expressions are developed for the transmission of vibrational power between two coupled plate substructures in an L configuration, with one of the surfaces of one of the plate substructures being subjected to a distributed load. The types of distributed loads that are considered are a force load with an arbitrary function in space and a distributed load similar to that from acoustic excitation.

Cuschieri, J. M.

1988-01-01

441

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

442

Selecting the best point of connection for shunt active filters in multi-bus power distribution systems  

Microsoft Academic Search

Since shunt active power filters operate as controlled current sources injecting current harmonic components to the power distribution system, the point of connection must be carefully selected so the generated harmonic components flow to the nonlinear loads and do not propagate through the distribution system. In this paper an analytical procedure based in the power distribution system voltage and current

L. Moran; J. Mahomar; J. Dixon

2002-01-01

443

PEV-based P-Q Control in Line Distribution Networks with High Requirement for Reactive Power Compensation  

E-print Network

, in particular, as distributed generation (DG) units become more popular. Currently, reactive power compensation1 PEV-based P-Q Control in Line Distribution Networks with High Requirement for Reactive Power impact of distribution level wind turbines. Our design is based on a nonlinear power flow analysis

Huang, Jianwei

444

Optimal reactive power planning for distribution systems considering intermittent wind power using Markov model and genetic algorithm  

NASA Astrophysics Data System (ADS)

Wind farms, photovoltaic arrays, fuel cells, and micro-turbines are all considered to be Distributed Generation (DG). DG is defined as the generation of power which is dispersed throughout a utility's service territory and either connected to the utility's distribution system or isolated in a small grid. This thesis addresses modeling and economic issues pertaining to the optimal reactive power planning for distribution system with wind power generation (WPG) units. Wind farms are inclined to cause reverse power flows and voltage variations due to the random-like outputs of wind turbines. To deal with this kind of problem caused by wide spread usage of wind power generation, this thesis investigates voltage and reactive power controls in such a distribution system. Consequently static capacitors (SC) and transformer taps are introduced into the system and treated as controllers. For the purpose of getting optimum voltage and realizing reactive power control, the research proposes a proper coordination among the controllers like on-load tap changer (OLTC), feeder-switched capacitors. What's more, in order to simulate its uncertainty, the wind power generation is modeled by the Markov model. In that way, calculating the probabilities for all the scenarios is possible. Some outputs with consecutive and discrete values have been used for transition between successive time states and within state wind speeds. The thesis will describe the method to generate the wind speed time series from the transition probability matrix. After that, utilizing genetic algorithm, the optimal locations of SCs, the sizes of SCs and transformer taps are determined so as to minimize the cost or minimize the power loss, and more importantly improve voltage profiles. The applicability of the proposed method is verified through simulation on a 9-bus system and a 30-bus system respectively. At last, the simulation results indicate that as long as the available capacitors are able to sufficiently compensate the reactive power demand, the DG operation no longer imposes a significant effect on the voltage fluctuations in the distribution system. And the proposed approach is efficient, simple and straightforward.

Li, Cheng

445

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

446

Distributed power from solar tower systems: a MIUS approach  

Microsoft Academic Search

One of the short-term priorities for renewable energies in Europe is their integration into communities and energy islands for local power supply (blocks of buildings, new neighborhoods in residential areas, shopping centers, hospitals, recreational areas, eco-parks, small rural areas or isolated ones such as islands or mountain communities). Following this strategy, the integration of small solar tower fields into so-called

Manuel Romero; Mar??a J. Marcos; Félix M. Téllez; Manuel Blanco; Valerio Fernández; Francisco Baonza; Sebastien Berger

1999-01-01

447

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

448

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

449

Impact of amorphous metal based transformers on efficiency and quality of electric power distribution  

Microsoft Academic Search

The dramatic increase in the use of power electronics and conditioning devices in addition to ubiquitous nonlinear electrical equipment such as motor drives has resulted in a considerable amount of higher harmonics of the line frequency. These high frequency harmonics lead to increased transformer core losses, especially in power distribution transformers that use conventional steel core materials. Amorphous metal core

R. Hasegawa

2001-01-01

450

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

451

High-power high-speed velocity-matched distributed photodetectors  

Microsoft Academic Search

The velocity-matched distributed photodetectors (VMDP) with high saturation power and large bandwidth have been proposed and demonstrated. The theoretical analysis on the trade-off between saturation power and bandwidth shows that VMDP provides fundamental advantages over conventional photodetectors. The theory for designing and simulating the performance of the VMDP is developed comprehensively from the aspect of microwave transmission line, optical waveguide,

Lih-Yuan Lin; Ming C. Wu; Tatsuo Itoh; Timothy A. Vang; Richard E. Muller; Deborah L. Sivco; Alfred Y. Cho

1997-01-01

452

Software development with computer graphics, distributed data base and OOP for deregulated power systems analysis  

Microsoft Academic Search

In this paper is reported the software development for power systems analysis using several techniques combining the object oriented programming paradigm, computer graphics techniques, distributed data base and software engineering. Three software packages have been implemented: CAPS, SIGVNS and TREINOM. CAPS package is oriented for interactive analysis of power systems and electric markets. SIGVNS is intended for calculation of the

V. L. Paucar; I. O. Almeida; M. J. Rider; M. F. Bedrinana; J. H. Santos

2004-01-01

453

Study of hydraulic power recovery from New Mexico water distribution systems  

Microsoft Academic Search

The results of a survey of New Mexico water distribution systems suitable for hydroelectric power development are reported. The objectives of the survey were to determine the potential for hydraulic power recovery from existing and planned water systems, to identify potential sites, and to study and recommend promising sites for further development. The survey found eleven sites in New Mexico

Schoenmackers

1984-01-01

454

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

455

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

456

A majorization-minimization approach to design of power distribution networks  

Microsoft Academic Search

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

Jason K Johnson; Michael Chertkov

2010-01-01

457

Fuzzy dynamic programming approach to reactive power\\/voltage control in a distribution substation  

Microsoft Academic Search

A fuzzy dynamic programming (FDP) approach is proposed for solving the reactive power\\/voltage control problem in a distribution substation. The main purpose is to improve the voltage profile on the secondary bus and restrain the reactive power flow into a main transformer at the same time. To reach our objectives, the load tap changer (LTC) usually installed in a main

Feng-Chang Lu; Yuan-Yih Hsu

1997-01-01

458

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

459

Probabilistic load flow in distribution systems containing dispersed wind power generation  

Microsoft Academic Search

A probabilistic model for the active power produced and the reactive power absorbed by wind turbines (WTs) equipped with induction generators is developed which takes into account the probabilistic nature of short-term wind velocity forecasts. The model is incorporated in a radial distribution load flow program which allows probabilistic modeling of loads at the MV\\/LV substation level and of voltage

N. D. Hatziargyriou; T. S. Karakatsanis; M. Papadopoulos

1993-01-01

460

Innovative training techniques to account for power quality issues when deploying distributed energy resources  

Microsoft Academic Search

Sizing and optimizing an investment in distributed energy resources (DER) must take into account power quality issues: it is then a matter of defining the right balance between the end-user's energy supply expectations and their financial capabilities to launch the investment. This requires a minimum understanding of power quality constraints during the DER unit optimization process: bridging the knowledge gaps

C. Coujard; A. Vafeas; S. Galant; R. Rodriguez; M. Bollen; S. Grenard

2007-01-01

461

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

462

An Electricity Trade Model for Multiple Power Distribution Networks in Smart Energy Systems  

E-print Network

and solar [5]. This however is very challenging due to the fact that power demand depends on a varietyAn Electricity Trade Model for Multiple Power Distribution Networks in Smart Energy Systems University of Southern California, Los Angeles, CA, USA {tcui, yanzhiwa, snazaria, pedram}@usc.edu Abstract

Pedram, Massoud

463

Modeling and measurement of a high-performance computer power distribution system  

Microsoft Academic Search

This paper describes a study whose purpose was to provide a methodology to accurately model entire high-performance computer power distribution systems, from power supply to load. Simulation and measurement results for a CMOS microprocessor system are shown to compare favorably

R. Evans; M. Tsuk

1994-01-01

464

Active and reactive power control of Proton Electrolyte Membrane Fuel Cell based Distributed Generation System  

Microsoft Academic Search

This paper deals with the design, a and control of Fuel Cell based Distributed G This includes the modeling of Proton Electrolyt Cell and the Power Conditioning Unit interfaci the Utility Grid with proper power flow contr the Fuel Cell Stack is connected to the DC si Source Inverter for interfacing to the Grid. transfer is based on the phase

Gitanjali Mehta; S. P. Singh

2011-01-01

465

A laboratory based microgrid and distributed generation infrastructure for studying connectivity issues to operational power systems  

Microsoft Academic Search

This paper presents an infrastructure and laboratory implementation of a hardware test-bed system emulating alternate sources and conventional power plant emulators connected as a complete power system. The distributed generation components were connected to the test-bed to study the issues of connecting alternates and various types of loads during operations. The various sources and loads can be connected in varying

O. A. Mohammed; M. A. Nayeem; A. K. Kaviani

2010-01-01

466

Dynamic simulation of microturbine distributed generators integrated with multi-machines power system network  

Microsoft Academic Search

This paper describing modellings and dynamic simulations of microturbine generation system (MTGS) in distribution system connected to multi-machines network. MTGS model is developed with the consideration of simulating a large number of these units in a large interconnected power system. Simulations are performed considering grid codes requirement. Dynamics of this integrated power system when subjected to a disturbance is studied

M. Z. C. Wanik; I. Erlich

2008-01-01

467

Effect of substrate resistivity on switching noise in on-chip power distribution networks  

Microsoft Academic Search

This paper describes the effect of substrate loss on simultaneous switching noise (SSN) in on-chip power distribution networks (PDN). Conformal mapping and first-order Debye approximation based Finite Difference Time Domain (FDTD) have been used for model extraction and time domain simulation with frequency dependent parameters, respectively. The importance of substrate loss on power supply noise has been quantified in this

Jifeng Mao; M. Swaminathan; J. Libous; D. O'Connor

2003-01-01

468

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

469

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

470

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

471

Technology survey of electrical power generation and distribution for MIUS application  

NASA Technical Reports Server (NTRS)

Candidate electrical generation power systems for the modular integrated utility systems (MIUS) program are described. Literature surveys were conducted to cover both conventional and exotic generators. Heat-recovery equipment associated with conventional power systems and supporting equipment are also discussed. Typical ranges of operating conditions and generating efficiencies are described. Power distribution is discussed briefly. Those systems that appear to be applicable to MIUS have been indicated, and the criteria for equipment selection are discussed.

Gill, W. L.; Redding, T. E.

1975-01-01

472

Progress in Development of a Low Energy Reaction Cell for Distributed Power Applications  

Microsoft Academic Search

Power units using Low Energy Nuclear Reactions (LENRs) potentially offer a radical new approach to power units that could provide distributed power units in the 1-50 kW range. As described in prior ICONE papers [9, 23] these cells employ thin metallic film cathodes (order of 500 Angstrom, using variously Ni, Pd and Ti) with electrolytes such as 0.5-1 molar lithium

G. H. Miley; C. Castano; A. Lipson; S. O. Kim; N. Luo

2002-01-01

473

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...

474

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

475

Influence of Channel Power and Pumping Configuration on the Gain Profile of Distributed Raman Fibre Amplifier  

Microsoft Academic Search

The influence of channel power and pumping configuration on the gain profile of a distributed Raman fibre amplifier has been experimentally measured. The experimental results show that the influence is significant and should be considered during the gain flatness optimization of the distributed Raman fibre amplifier.

Xiang-Jun Xin; Chong-Xiu Yu; Ru Zhang; Jian-Hua Ren; An-Jian Li; Qiang Wu; Yu Xin; Chuan-Lin Wang; Wen-Xiao Zheng; Shuang-Chen Ruan; Ge-Guo Du; Gang Xin; Xiao-Qiang Yang

2003-01-01

476

Modern Electric-Power-Distribution Ideas as Applied in a Large War Plant  

Microsoft Academic Search

It may be concluded, without reservation, that the application of load-center distribution principles as herein described was responsible for an amazing reduction in material investment, principally copper and steel, compared with that which would have been required by power-distribution methods employed only a short time ago. In the planning of this project, the greatest emphasis constantly was placed on conservation

R. H. Kaufmann; N. A. Kieb

1945-01-01

477

Relationship between Statistical Distributions of Impinging and Stressing Overvoltages in Power Cable Lines  

Microsoft Academic Search

The knowledge of the statistical distribution of the overvoltages stressing the insulation of a cable line is fundamental for the insulation coordination. The estimation of such distributions requires the utilization of complex numerical programs. In this paper a simplified method which takes into account a typical configuration in a power system \\

M. Marzinotto

2007-01-01

478

Maximum load distribution between turbo units of thermal power plants by computers  

Microsoft Academic Search

It is concluded that the optimum load distribution between the turbo units of thermal power plants is an important source of increase for their efficiency. The load between the turbo units should be distributed based on the most representative characteristics reflecting all the features of operation of the turbo units under different conditions. The operative and exact solution of the

L. S. Foshko; L. B. Zusmanovich; S. L. Flos; V. A. Palchi; B. I. Kovevski

1979-01-01

479

Current control method for distributed generation power generation plants under grid fault conditions  

Microsoft Academic Search

The operation of distributed power generation systems under grid fault conditions is a key issue for the massive integration of renewable energy systems. Several studies have been conducted to improve the response of such distributed generation systems under voltage dips. In spite of being less severe, unbalanced fault cause a great number of disconnections, as it may produce the injection

Pedro Rodriguez; Alvaro Luna; Juan Ramon Hermoso; Ion Etxeberria-Otadui; Remus Teodorescu; Frede Blaabjerg

2011-01-01

480

SmartGrid: Future networks for New Zealand power systems incorporating distributed generation  

Microsoft Academic Search

The concept of intelligent electricity grids, which primarily involves the integration of new information and communication technologies with power transmission lines and distribution cables, is being actively explored in the European Union and the United States. Both developments share common technological developmental goals but also differ distinctly towards the role of distributed generation for their future electrical energy security. This

Nirmal-Kumar C. Nair; Lixi Zhang

2009-01-01

481

A Two-Stage Distributed Architecture for Voltage Control in Power Distribution Systems  

E-print Network

can collectively provide the reactive power estimated by the local controller, they are instructed, the additional power demand introduced by massive charging of PHEVs can potentially cause unacceptable voltage drops [8]. Voltage violations are traditionally handled by automatically- controlled tap-changing under

Hadjicostis, Christoforos

482

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

483

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

E-print Network

with a certain polarity across the combination of a filter and a loudspeaker, as decided by the control algorithm of the mains power into acoustic output in one simplified topological stage, like in the active loudspeaker

484

Progress in L-Band Power Distribution System R&D at SLAC  

SciTech Connect

We report on the L-band RF power distribution system (PDS) developed at SLAC for Fermilab's NML superconducting test accelerator facility. The makeup of the system, which allows tailoring of the power distribution to cavities by pairs, is briefly described. Cold test measurements of the system and the results of high power processing are presented. We also investigate the feasibility of eliminating the expensive, lossy circulators from the PDS by pair-feeding cavities through custom 3-dB hybrids. A computational model is used to simulate the impact on cavity field stability due to the reduced cavity-to-cavity isolation.

Nantista, Christopher; Adolphsen, Chris; Wang, Faya; /SLAC

2008-10-20

485

Low-power clock distribution circuits for the Macro Pixel ASIC  

NASA Astrophysics Data System (ADS)

Clock distribution circuits account for a significant fraction of the power dissipation of the Macro Pixel ASIC (MPA), designed for the pixel layer readout of the so-called Pixel-Strip module in the innermost part of the CMS tracker at the HL-LHC. This work reviews different CMOS circuit architectures envisioned for low power clock distribution in the MPA. Two main topologies will be discussed, based on standard supply voltage and on auxiliary, reduced supply. Circuit performance, in terms of power consumption and speed, is evaluated for each of the proposed solutions and compared with that relevant to standard CMOS drivers.

Gaioni, L.; De Canio, F.; Manghisoni, M.; Ratti, L.; Re, V.; Traversi, G.; Marchioro, A.; Kloukinas, K.

2015-01-01

486

Power quality enhancement at distribution level utilizing the unified power quality conditioner (UPQC)  

Microsoft Academic Search

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

Vinod Khadkikar

2008-01-01

487

Adding damping in power distribution systems by means of power electronic converters  

Microsoft Academic Search

The amount of non-linear and unbalanced loads (such as adjustable speed drives and personal computers) connected to the electric power system is steadily growing. As a result, the power quality i.e. the reliability of the energy supply and the quality of the voltage waveform, may be severely degraded. Especially in the case of resonances, severe voltage distortion can be the

Wouter R. Ryckaert; K. De Gusseme; D. M. Van de Sype; J. J. Desmet; J. A. Melkebeek

2005-01-01

488

Distributed control for automatic fire detection and monitoring system for a nuclear power plant  

SciTech Connect

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 Control Panel, and (3) Nuclear Power Plant Security Control Panel. The technical details of the main components, including computer specifications, is described. The advantages and disadvantages of using a distributed control system for this specific application are painted out.

Bagchi, C.N.; Chakraberti, A.K.

1984-01-01

489

Universal inverse power-law distribution for temperature and rainfall in the UK region  

NASA Astrophysics Data System (ADS)

Meteorological parameters, such as temperature, rainfall, pressure, etc., exhibit selfsimilar space-time fractal fluctuations generic to dynamical systems in nature such as fluid flows, spread of forest fires, earthquakes, etc. The power spectra of fractal fluctuations display inverse power-law form signifying long-range correlations. A general systems theory model predicts universal inverse power-law form incorporating the golden mean for the fractal fluctuations. The model predicted distribution was compared with observed distribution of fractal fluctuations of all size scales (small, large and extreme values) in the historic month-wise temperature (maximum and minimum) and total rainfall for the four stations Oxford, Armagh, Durham and Stornoway in the UK region, for data periods ranging from 92 years to 160 years. For each parameter, the two cumulative probability distributions, namely cmax and cmin starting from respectively maximum and minimum data value were used. The results of the study show that (i) temperature distributions (maximum and minimum) follow model predicted distribution except for Stornowy, minimum temperature cmin. (ii) Rainfall distribution for cmin follow model predicted distribution for all the four stations. (iii) Rainfall distribution for cmax follows model predicted distribution for the two stations Armagh and Stornoway. The present study suggests that fractal fluctuations result from the superimposition of eddy continuum fluctuations.

Selvam, A. M.

2014-06-01

490

The integration of renewable energy sources into electric power distribution systems. Volume 1: National assessment  

SciTech Connect

Renewable energy technologies such as photovoltaic, solar thermal electricity, and wind turbine power are environmentally beneficial sources of electric power generation. The integration of renewable energy sources into electric power distribution systems can provide additional economic benefits because of a reduction in the losses associated with transmission and distribution lines. Benefits associated with the deferment of transmission and distribution investment may also be possible for cases where there is a high correlation between peak circuit load and renewable energy electric generation, such as photovoltaic systems in the Southwest. Case studies were conducted with actual power distribution system data for seven electric utilities with the participation of those utilities. Integrating renewable energy systems into electric power distribution systems increased the value of the benefits by about 20 to 55% above central station benefits in the national regional assessment. In the case studies presented in Vol. II, the range was larger: from a few percent to near 80% for a case where costly investments were deferred. In general, additional savings of at least 10 to 20% can be expected by integrating at the distribution level. Wind energy systems were found to be economical in good wind resource regions, whereas photovoltaic systems costs are presently a factor of 2.5 too expensive under the most favorable conditions.

Barnes, P.R.; Van Dyke, J.W. [Oak Ridge National Lab., TN (United States); Tesche, F.M. [6714 Norway Road, Dallas, TX (United States); Zaininger, H.W. [Zaininger Engineering Co., San Jose, CA (United States)

1994-06-01

491

Hysteresis, Phase Transitions and Dangerous Transients in Electrical Power Distribution Systems  

E-print Network

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 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 spatio-temporal 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 ...

Duclut, Charlie; Chertkov, Michael

2012-01-01

492

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

E-print Network

for air conditioning, refrigeration, water pumping, ventilation etc. Accurate knowledge of these motor. Conventional excitation controllers coupled with power system stabilisers (PSSs) for centralised generation parameters and their dependency on operating conditions is critical to identify [3]. Any robust controller

Pota, Himanshu Roy

493

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

494

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

495

Learning Geo-Temporal Non-Stationary Failure and Recovery of Power Distribution  

E-print Network

Smart energy grid is an emerging area for new applications of machine learning in a non-stationary environment. Such a non-stationary environment emerges when large-scale failures occur at power distribution networks due to external disturbances 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 non-stationary behaviors of large-scale failure and recovery of power distribution. This work studies such non-stationary 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 geo-location based multivariate non-stationary GI(t)/G(t)/Infinity queues. Third, the non-stationary spatial-temporal models identify a small number of parameters to be learned. Learning is applied to two ...

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

2013-01-01

496

Integration of distributed generation in the power system - a power quality approach  

Microsoft Academic Search

This paper gives an overview of the design and operation issues in distribution and transmission systems due to the integration of distributed generation. The hosting-capacity approach has been developed to obtain a quantitative measure on the amount of generation that can be connected without impairing the performance of the system. The hosting-capacity approach requires a set of well-defined performance indices

M. H. J. Bollen; Y. Yang; F. Hassan

2008-01-01

497

New Power Electronics Converter Interfacing a Hybrid Dc/Ac Microgrid M. Alibeik, E. C. dos Santos Jr.  

E-print Network

Jr. Department of Electrical and Computer Engineering, School of Engineering and Technology Indiana switch and drive circuitry. However the proposed circuit maintains the same features of the conventional, (ii) independent control in both ac and dc parts, and (iii) different operation conditions using

Zhou, Yaoqi

498

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

499

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 Electric