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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

Design of AC auxiliary power distribution systems for large TVA thermal power generating plants  

Microsoft Academic Search

This paper discusses TVA's practices in the design of ac auxiliary power distribution systems of large thermal generating plants. Its scope is limited to the primary portions of the system, including the station service transformers which step down the main generator voltage or switchyard voltage, and the switchgear and buses which distribute power from the secondaries of these transformers. Single-line

G. R. Reed; D. R. Webster

1975-01-01

3

AC\\/DC Smart Control and Power Sharing of DC Distribution Systems  

Microsoft Academic Search

The purpose of this research is to develop a grid connected DC distribution system to ensure efficient integration of different alternate sources to the power system. An investigation of different AC and DC converter topologies and their control is conducted. A new converter topology for sharing DC power was developed to enhance the efficiency and stability of the alternate sources

Mohamed A Elshaer

2012-01-01

4

Trolleybus power system for operation with AC or DC distribution networks  

Microsoft Academic Search

This paper presents the development and experimental analysis of a special input stage converter for a Trolleybus type vehicle allowing its operation in AC (two wires, single-phase) or DC distribution networks. The architecture of proposed input stage converter is composed by five interleaved boost rectifiers operating in discontinuous conduction mode. Furthermore, due to the power lines characteristics, the proposed input

G. A. Melo; F. A. S. Gonc?alves; R. N. Oliveira; J. M. Muno; M. Santos; C. A. Canesin

2010-01-01

5

Analysis and design-optimization of LCC resonant inverter for high-frequency AC distributed power system  

Microsoft Academic Search

The analysis and design of an LCC resonant inverter for a 20 kHz AC distributed power system are presented. Several resonant converter topologies are assessed to determine their suitability for high efficiency power conversion, under resistive and reactive loads. Two LCC-resonant inverter designs were implemented. One with all switches operating with zero voltage switching (ZVS), and another with two switches

J. A. Sabate; M. M. Jovanovic; F. C. Lee; R. T. Gean

1995-01-01

6

AC power electronic systems: Stability and power quality  

Microsoft Academic Search

This paper presents an overview of ac power electronic system modeling and analysis methods. Characteristics of such systems are first discussed, and their applications and significance in renewable energy and distributed generation (DG), transportation, and other mobile and autonomous power systems are highlighted. Typical stability and power quality problems encountered in these systems are demonstrated by measurements from several practical

Jian Sun

2008-01-01

7

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

8

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

9

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

10

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

11

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

12

Dual Robust Controller Design for High Power AC Servo Drive  

Microsoft Academic Search

High power AC motors have a highly interacting multivariable control structure, and it is difficult to design high dynamic performance AC drive with traditional PID-like controller for high power AC servo motor. This paper presents analysis, design and simulation of velocity loop dual robust controller for 11 kw permanent magnetic synchronous motor (PMSM) in the AC servo system. By combining

Stone Cheng; Yuan-Yong Huang; Hsin-Hung Chou

2008-01-01

13

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 Food and...Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either...

2010-04-01

14

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false AC-powered patient lift. 880.5500 Section 880.5500 Food and...Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either...

2011-04-01

15

21 CFR 880.5500 - AC-powered patient lift.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false AC-powered patient lift. 880.5500 Section 880.5500 Food and...Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either...

2012-04-01

16

Thermoelectric AC power sensor by CMOS technology  

Microsoft Academic Search

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

Dominik Jaeggi; Henry Baltes; David Moser

1992-01-01

17

Power control for ac motor  

NASA Technical Reports Server (NTRS)

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

Dabney, R. W. (inventor)

1984-01-01

18

Power control for ac motor  

NASA Astrophysics Data System (ADS)

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

Dabney, R. W.

1984-12-01

19

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

20

High Power Electronics and flexible AC Transmission System  

Microsoft Academic Search

During the last decade, higher energy costs, the difficulty in building new power plants and improved converter technology provided an increased Market for HVDC transmission. However, HVDC, due to the high cost of converters, will play a limited role in the overall ac power system. The author discusses the potential of thyristors in ac power systems. The concept of a

N. G. Hingorani

1988-01-01

21

POWER ELECTRONICS HARMONIC ANALYSIS BASED ON THE LINEAR TIME PERIODIC MODELING. APPLICATIONS FOR AC/DC/AC POWER  

E-print Network

1 POWER ELECTRONICS HARMONIC ANALYSIS BASED ON THE LINEAR TIME PERIODIC MODELING. APPLICATIONS FOR AC/DC/AC POWER ELECTRONIC INTERFACE. Vanya Ignatova*, Pierre Granjon**, Seddik Bacha* *LEG in power electronic systems. The considered system is described by a set of differential equations, which

Paris-Sud XI, Université de

22

Hybrid DC and AC-Linked Microgrids: Towards Integration of Distributed Energy Resources  

Microsoft Academic Search

This paper presents a microgrid paradigm with both DC and AC links, which may provide an effective way to integrate a heterogeneous set of small-size distributed energy resources into the existing electric power infrastructure. The collection of aggregated energy resource units at each level represents those distributed resources to the upper level as a single self-regulated entity (as a DC

Zhenhua Jiang; Xunwei Yu

2008-01-01

23

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

24

Electrical Model of Balanced AC HTS Power Cable  

NASA Astrophysics Data System (ADS)

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

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

25

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

26

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

Microsoft Academic Search

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

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

2010-01-01

27

Detailed distribution of AC loss in the NET TF coil  

SciTech Connect

The AC loss in the NET (Next European Torus) TF coil has been computed as a function of space and time using a field map of the DC toroidal field components and AC poloidal field components for three proposed conductor designs. Resolving the field B, field change ..delta..B and field derivative B into components transversal and parallel to the conductors, the value of the coupling, eddy currents and hysteresis losses was computed using a set of simplified expressions. The calculation performed on the whole coil is presented here using the distributions along a developed pancake of the instantaneous and average values of AC loss.

Bottura, L.; Minervini, J.

1989-03-01

28

SSP Power Management and Distribution  

NASA Technical Reports Server (NTRS)

Space Solar Power is a NASA program sponsored by Marshall Space Flight Center. The Paper presented here represents the architectural study of a large power management and distribution (PMAD) system. The PMAD supplies power to a microwave array for power beaming to an earth rectenna (Rectifier Antenna). The power is in the GW level.

Lynch, Thomas H.; Roth, A. (Technical Monitor)

2000-01-01

29

High Voltage AC Power Transmission Lines and Communications Receiver Sites.  

National Technical Information Service (NTIS)

A short discussion of the effects of the Electromagnetic Interference (EMI) radiated from High Voltage AC (HVAC) Power Transmission lines on HF Communications Receivers is followed by the description of a method for choosing communications receiver sites ...

F. R. Hill

1976-01-01

30

Control of Distributed Power Systems  

Microsoft Academic Search

A large number of distributed generation (DG) units are being integrated into power systems at distribution level. The DG units play an essential role in affecting the efficiency and performance of power systems. This paper describes some possible controlling modes of DG units. The operation and control of the power systems consisting of DG units, in particular separated subsystems, are

Z. Chen; Y Hu; F. Blaabjerg

2006-01-01

31

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

32

The Quality of U.S. Commercial AC Power  

Microsoft Academic Search

From May 1977 through September 1979, the Bell System conducted a study of commercial ac power disturbances ¿ To determine their nature and extent ¿ To devise statistical ways of predicting their occurrence ¿ To reduce or eliminate computer downtime through selection of appropriate, cost-effective power-conditioning equipment for use throughout the System. For a total of 270 months, field data

M. Goldstein; P. D. Speranza

1982-01-01

33

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

E-print Network

New Power Electronics Converter Interfacing a Hybrid Dc/Ac Microgrid M. Alibeik, E. C. dos Santos integrated power electronics converter able to connect a Distributed Generation (DG) unit with a hybrid dc microgrid is that it has higher efficiency and lesser power conversion. In this work is proposed a new

Zhou, Yaoqi

34

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

35

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

Microsoft Academic Search

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

Jin Aijuan; Li. Hangtian; Li Shaolong

2006-01-01

36

High power clean DC bus generation using AC-link AC to DC power voltage conversion, DC regulation, and galvanic isolation  

Microsoft Academic Search

The proliferation of large non linear loads such as main propulsion and thruster variable frequency drives (VFDs) on both warships and commercial vessels, high voltage power supplies for lasers and other advanced weapons on warships require both AC voltage transformation and power conversion from AC to DC. For VFDs, rectification from AC to DC and inversion from DC back to

Ian C Evans; Rudy Limpaecher

2009-01-01

37

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

Microsoft Academic Search

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

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

2008-01-01

38

Steady State Stability Analysis of AC-DC Power Systems  

Microsoft Academic Search

This thesis presents a comprehensive approach for the steady state stability analysis of AC-DC power systems. A new method is presented for the evaluation of the system state matrix which is then used to determine system stability and develop new algorithms for the stability analysis and control of large power systems.\\u000aThe method exploits the powerful features of the Component

Farooq Ahmad Qureshy

1985-01-01

39

Ac/dc/ac high voltage traction drives with quasi-zero reactive power demand  

SciTech Connect

The new GTO devices allow the design of forced-commuted high power converters (up to several MVA`s). However, they cannot operate at high switching frequency, thus producing waveforms affected by remarkable harmonic distortion, especially if conventional converter topologies are used. A novel ac/dc/ac conversion structure has been developed referring to single-phase ac (25 kV/50 Hz) traction systems; 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 to control the whole system, assuring a quasi-unitary power factor and a low distorted line current. Simulation results confirm the validity of the methodologies proposed and of the analyses performed.

Bertini, S.; Ghiara, T.; Marchesoni, M. [Univ. of Genova (Italy). Dept. of Electrical Engineering] [Univ. of Genova (Italy). Dept. of Electrical Engineering

1993-10-01

40

Power Law Distribution in Education  

NASA Astrophysics Data System (ADS)

We studied the statistical distribution of student's performance, which is measured through their marks, in university entrance examination (Vestibular) of UNESP (Universidade Estadual Paulista) with respect to (i) period of study-day versus night period (ii) teaching conditions - private versus public school (iii) economical conditions - high versus low family income. We observed long ubiquitous power law tails in physical and biological sciences in all cases. The mean value increases with better study conditions followed by better teaching and economical conditions. In humanities, the distribution is close to normal distribution with very small tail. This indicates that these power law tails in science subjects are due to the nature of the subjects themselves. Further and better study, teaching and economical conditions are more important for physical and biological sciences in comparison to humanities at this level of study. We explain these statistical distributions through Gradually Truncated Power law distributions. We discuss the possible reason for this peculiar behavior.

Gupta, Hari M.; Campanha, José R.; Chavarette, Fábio R.

41

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

42

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

43

Save power in AC induction motors  

NASA Technical Reports Server (NTRS)

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

Nola, F. J.

1977-01-01

44

Measurement of AC magnetic field distribution using magnetic resonance imaging.  

PubMed

Electric currents are applied to body in numerous applications in medicine such as electrical impedance tomography, cardiac defibrillation, electrocautery, and physiotherapy. If the magnetic field within a region is measured, the currents generating these fields can be calculated using the curl operator. In this study, magnetic fields generated within a phantom by currents passing through an external wire is measured using a magnetic resonance imaging (MRI) system. A pulse sequence that is originally designed for mapping static magnetic field inhomogeneity is adapted. AC current in the form of a burst sine wave is applied synchronously with the pulse sequence. The frequency of the applied current is in the audio range with an amplitude of 175-mA rms. It is shown that each voxel value of sequential images obtained by the proposed pulse sequence is modulated similar to a single tone broadband frequency modulated (FM) waveform with the ac magnetic field strength determining the modulation index. An algorithm is developed to calculate the ac magnetic field intensity at each voxel using the frequency spectrum of the voxel signal. Experimental results show that the proposed algorithm can be used to calculate ac magnetic field distribution within a conducting sample that is placed in an MRI system. PMID:9368117

Ider, Y Z; Muftuler, L T

1997-10-01

45

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 Food...880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or...

2010-04-01

46

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Non-AC-powered patient lift. 880.5510 Section 880.5510 Food...880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or...

2012-04-01

47

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

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Non-AC-powered patient lift. 880.5510 Section 880.5510 Food...880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or...

2011-04-01

48

A grid interface for distributed energy resources with integrated energy storage using a high frequency AC link  

Microsoft Academic Search

A multiport converter with a high frequency (hf) ac bus is proposed for use as a distributed energy resource (DER) to grid interface with an integrated energy storage system (ESS). The combination of DER and ESS allows the DER to provide load following, load leveling, power quality compensation, voltage and frequency control, and spinning reserve, as well as savings on

Joseph A. Carr; Juan Carlos Balda

2008-01-01

49

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

50

Distributed vs. Centralized Power Systems Frequency Control  

E-print Network

Distributed vs. Centralized Power Systems Frequency Control Martin Andreasson12 , Dimos V control of electrical power systems. We propose a distributed controller which retains the reference class of large- scale systems are electrical power systems, which employ automatic generation control

Dimarogonas, Dimos

51

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

52

Improved dynamic security assessment for AC\\/DC power systems using energy functions  

Microsoft Academic Search

A method is presented to integrate the dynamics of DC power flow into calculations of transient energy functions of AC\\/DC power systems. This method treats the generator input power as a function of the parameters and the input, output variables of the DC damping power controller. By using this transient energy function, the accuracy of the stability prediction of AC\\/DC

Nilkamal Fernandopulle; Robert T. H. Alden

2003-01-01

53

Space station automation of common module power management and distribution  

NASA Technical Reports Server (NTRS)

The purpose is to automate a breadboard level Power Management and Distribution (PMAD) system which possesses many functional characteristics of a specified Space Station power system. The automation system was built upon 20 kHz ac source with redundancy of the power buses. There are two power distribution control units which furnish power to six load centers which in turn enable load circuits based upon a system generated schedule. The progress in building this specified autonomous system is described. Automation of Space Station Module PMAD was accomplished by segmenting the complete task in the following four independent tasks: (1) develop a detailed approach for PMAD automation; (2) define the software and hardware elements of automation; (3) develop the automation system for the PMAD breadboard; and (4) select an appropriate host processing environment.

Miller, W.; Jones, E.; Ashworth, B.; Riedesel, J.; Myers, C.; Freeman, K.; Steele, D.; Palmer, R.; Walsh, R.; Gohring, J.

1989-01-01

54

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

55

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

Microsoft Academic Search

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

K. Basu; N. Mohan

2010-01-01

56

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

Microsoft Academic Search

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

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

1992-01-01

57

Power distribution for electron beam welding  

NASA Technical Reports Server (NTRS)

The power distribution of an electron seam is analyzed. Digital computer techniques are used to evaluate the radial distribution of power detected by a wire probe circulating through the beam. Results are reported.

Edwards, E.

1980-01-01

58

Power quality and line considerations for variable speed ac drives  

SciTech Connect

Variable speed ac drives are finding their way into all types of industrial and commercial power system applications. Their application to the load (motor) generally is reasonably well selected--at least within heavy industry. However, there are many line (source) design parameters learned in the 1950`s and 1960`s which are now being frequently overlooked. This paper represents many years of experience doing power quality investigations. The authors combined this experience with recent technology and discuss some of the areas of concern which frequently result in serious performance or power quality problems. Finally, basic design guidelines are given to greatly minimize system problems--especially as newer technologies are intermixed with old.

Shipp, D.D.; Vilcheck, W.S. [Westinghouse Electric Corp., Oakdale, PA (United States)] [Westinghouse Electric Corp., Oakdale, PA (United States)

1996-03-01

59

Effect of soft ferromagnetic substrate on ac loss in 2G HTS power transmission cables consisting of coated conductors  

NASA Astrophysics Data System (ADS)

As a model of second-generation high-temperature superconducting (2G HTS) power transmission cable, the effect of soft ferromagnetic (FM) substrate on hysteretic ac loss in a round cable carrying transport current or exposed to radial magnetic field is investigated theoretically. We consider the FM substrates as ideal soft magnets with an infinite permeability, neglecting the magnetic hysteresis. The analytical expressions of field and current distribution around a curved superconductor tape with FM substrate were derived applying the complex-field approach. FM components can strongly influence the ac loss behaviors in a round cable composed of coated conductors. The approximate expressions for ac loss in a round cable at small currents or low fields are obtained. It is shown that at small currents the ac loss QFM in a round cable for FM substrate depended on ac current amplitude ia and central angle ?n as {\\propto }{i}_{{a}}^{2.7}({\\theta }_{n}\\cot {\\theta }_{n})^{1.8 6}, while at low fields ha {Q}_{{FM}}\\propto {h}_{{a}}^{2.7 5}/({\\theta }_{n}\\cot {\\theta }_{n})^{0.3 5}, the order of which differs significantly from QNM for nonmagnetic (NM) substrate. Additionally, the influence of the central angle as well as tape-width of coated conductors on the ac loss characteristic in a round cable is discussed. The ac loss QFM can be reduced by a suitable tape-width of coated conductor at higher fields as compared with QNM.

He, An; Xue, Cun; Yong, Huadong; Zhou, Youhe

2014-02-01

60

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

Microsoft Academic Search

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

Jin Aijuan; Li Hangtian; Li Shaolong

2005-01-01

61

Single-phase ac losses in prototype HTS conductors for superconducting power transmission lines  

SciTech Connect

The authors report single-phase ac loss measurements on 8, 4, and 3-layer, multi-strand, HTS prototype conductors for power transmission lines. They use both calorimetric and electrical techniques. The agreement between the two techniques suggests that the interlayer current distribution in one-meter long conductors are representative of those in long conductors. The losses for the 8 and 4-layer conductors are in rough agreement, with the 8-layer losses being somewhat lower. The 3-layer conductor losses are substantially higher--probably due to unbalanced azimuthal currents for this configuration.

Daney, D.E.; Maley, M.P.; Boenig, H.J.; Willis, J.O.; Coulter, J.Y. [Los Alamos National Lab., NM (United States); Gherardi, L.; Coletta, G. [Pirelli Cavi SpA (Italy)

1998-12-01

62

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

63

Distribution customer power quality experience  

Microsoft Academic Search

A proactive approach to determining power quality by monitoring voltage disturbances and harmonic levels dictated by a power quality survey program is discussed. The authors present and discuss in detail some of the key objectives of the power quality program. A methodology for quantifying power quality as experienced by customers in a graphical form is presented. Several detailed case studies

Brent M. Hughes; John S. Chan; D. O. Koval

1991-01-01

64

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

65

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

66

Some New Discrete Probability Distributions Derived from Power Series Distributions  

Microsoft Academic Search

Power series distributions (PSD) are well documented in the literature. Some of the well-known theoretical models in statistics, like Poisson, negative binomial, and geometric, belong to this family. Many real-life phenomena are represented by these models. Based on these models, some new probability distributions are obtained in this paper. By means of examples it is demonstrated that the derived distributions

G. Jayasree; R. J. R. Swamy

2006-01-01

67

Distribution of Activator (Ac) Throughout the Maize Genome for Use in Regional Mutagenesis  

PubMed Central

A collection of Activator (Ac)-containing, near-isogenic W22 inbred lines has been generated for use in regional mutagenesis experiments. Each line is homozygous for a single, precisely positioned Ac element and the Ds reporter, r1-sc:m3. Through classical and molecular genetic techniques, 158 transposed Ac elements (tr-Acs) were distributed throughout the maize genome and 41 were precisely placed on the linkage map utilizing multiple recombinant inbred populations. Several PCR techniques were utilized to amplify DNA fragments flanking tr-Ac insertions up to 8 kb in length. Sequencing and database searches of flanking DNA revealed that the majority of insertions are in hypomethylated, low- or single-copy sequences, indicating an insertion site preference for genic sequences in the genome. However, a number of Ac transposition events were to highly repetitive sequences in the genome. We present evidence that suggests Ac expression is regulated by genomic context resulting in subtle variations in Ac-mediated excision patterns. These tr-Ac lines can be utilized to isolate genes with unknown function, to conduct fine-scale genetic mapping experiments, and to generate novel allelic diversity in applied breeding programs. PMID:15520264

Kolkman, Judith M.; Conrad, Liza J.; Farmer, Phyllis R.; Hardeman, Kristine; Ahern, Kevin R.; Lewis, Paul E.; Sawers, Ruairidh J. H.; Lebejko, Sara; Chomet, Paul; Brutnell, Thomas P.

2005-01-01

68

A distributed power generation communication system  

Microsoft Academic Search

A distributed power generation system (DPGS) consists of a number of small-scale power generation sources (SSPGS) that provide electric power at a site closer to the user than the central power generation station. Small-scale power generation technologies currently available include wind turbines, fuel cells, micro gas\\/diesel turbines, small hydro generators and photovoltaic panels. Currently, most SSPGSs are locally controlled and

Julian Meng

2003-01-01

69

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

Microsoft Academic Search

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

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

1993-01-01

70

Group maximum power tracking for distributed power sources  

NASA Astrophysics Data System (ADS)

This paper offers a useful application of Uniform Input Voltage Distribution (UIVD) control [6-9] for Distributed-Input Parallel-Output (DIPO) converter power systems. The primary control objective of UIVD for DIPO converters is to achieve grouped maximum power throughput from non-identical renewable power sources. Secondly, this paper features a revised Maximum Power Tracking (MPT) controller design developed for DIPO configurations that facilitate simultaneous processing of distributed power flows. In earlier research, the distributed source peak powers are individually tracked by converters controlled by independent MPT controllers without UIVD. However, when distributed power sources have similar peak power voltages with an achievable tracking efficiency of greater than 96%, such independent MPT controllers are not necessary. By utilizing UIVD control, near-maximum use of available power is achieved using a single MPT controller. The resulting system and control architectures offer near-maximum power transfer with a lower parts count. Two DIPO power converter bus architectures are described herein: one having a battery-dominated output voltage and the other with a regulated output voltage. Through computer simulation and prototype testing, both power architectures are validated for fault-tolerant grouped UIVD control.

Siri, Kasemsan

71

Advanced Power Electronic Interfaces for Distributed  

E-print Network

Advanced Power Electronic Interfaces for Distributed Energy Systems Part 2: Modeling, Development. Chakraborty, B. Kroposki, and W. Kramer Technical Report NREL/TP-550-44313 November 2008 #12;Advanced Power Electronic Interfaces for Distributed Energy Systems Part 2: Modeling, Development, and Experimental

72

Distribution customer power quality experience  

Microsoft Academic Search

There has been a significant increase in the number of disturbance-producing loads and sensitive loads being utilized, resulting in increased customer complaints being directed at utilities. BC Hydro is taking a proactive approach in determining its own power quality by monitoring voltage disturbances and harmonic levels dictated by a power quality survey program. The authors present and discuss in detail

Brent M. Hughes; John S. Chan; D. O. Koval

1993-01-01

73

Autonomous power management and distribution  

NASA Technical Reports Server (NTRS)

The goal of the Autonomous Power System program is to develop and apply intelligent problem solving and control to the Space Station Freedom's electric power testbed being developed at NASA's Lewis Research Center. Objectives are to establish artificial intelligence technology paths, craft knowledge-based tools and products for power systems, and integrate knowledge-based and conventional controllers. This program represents a joint effort between the Space Station and Office of Aeronautics and Space Technology to develop and demonstrate space electric power automation technology capable of: (1) detection and classification of system operating status, (2) diagnosis of failure causes, and (3) cooperative problem solving for power scheduling and failure recovery. Program details, status, and plans will be presented.

Dolce, Jim; Kish, Jim

1990-01-01

74

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 controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection wind farm control involves both the control on wind turbine level as well as the central control

75

An Advanced Distributed Power Supply for Power Electronic Transformers  

Microsoft Academic Search

The idea of power electronic transformer (PET), which work with solid-state switches, have been considered noticeably recently. Every power electronic transformer has several parts which each of them needs its own reliable supply voltage. So the appropriate performance of a PET depends on the existence of various proper supply voltages. The distributed power supply (DPS), which can produce several different

M. Saghaleini; A. Hekmati; S. Farhangi

2007-01-01

76

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

77

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

78

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

79

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 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 §...

2011-04-01

80

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

...2014-04-01 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 §...

2014-04-01

81

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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 §...

2013-04-01

82

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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 §...

2012-04-01

83

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION...AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND...

2011-04-01

84

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION...AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND...

2010-04-01

85

21 CFR 880.6320 - AC-powered medical examination light.  

...2014-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION...AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND...

2014-04-01

86

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION...AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND...

2012-04-01

87

21 CFR 880.6320 - AC-powered medical examination light.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false AC-powered medical examination light. 880.6320 Section 880.6320 Food and Drugs FOOD AND DRUG ADMINISTRATION...AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND...

2013-04-01

88

Electric power distribution and load transfer system  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

89

Mobile Power Distribution Unit for High Voltages.  

National Technical Information Service (NTIS)

The patent describes a rail-mounted three-phase mobile open distribution unit operating on 220 KV mounted on transportable platforms and containing a power transformer, disconnector units, separator units, a shorting switch, and dischargers. In order to r...

B. M. Gamburg, D. A. Myslin, K. S. Bessonov

1972-01-01

90

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

91

Intelligent Systems for Power Management and Distribution  

NASA Technical Reports Server (NTRS)

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

Button, Robert M.

2002-01-01

92

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

93

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

94

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

95

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

Microsoft Academic Search

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

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

2010-01-01

96

A high power density high voltage distributed power system for pulse power applications  

Microsoft Academic Search

In this paper, a high-density high-voltage distributed power system for pulse power applications is designed and implemented. Different topologies are evaluated for two power stages. According to pulse load condition, system power density is optimized through the tradeoff between power loss and magnetic component size. High power density and high efficiency are verified by the experimental result

Bing Lu; Yarig Qiu; Chuanyun Wang; Yonghan Kang; Juanjuan Sun; Wei Dong; Francisco Canales; Peter Barbosa; Ming Xu; Fred C. Lee; Richard Gean; Wesley C. Tipton; Damian Urciuoli

2005-01-01

97

Optical power distributions through fractal routing  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

98

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

99

Development of software to improve AC power quality on large spacecraft  

Microsoft Academic Search

To insure the reliability of a 20 kHz, alternating current (AC) power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can become a serious problem. It can cause malfunctions in equipment that the power system is supplying, and,

L. Alan Kraft

1991-01-01

100

Very high performance AC\\/DC\\/DC converter architecture for traction power supplies  

Microsoft Academic Search

This paper presents a very high efficiency AC\\/DC\\/DC converter topology suitable for all those applications dealing with high power requirements and good handling of very wide input voltage variations, such as Traction auxiliary services. In particular, to enhance high conversion efficiency together with high reliability and cost reduction, the document addresses the use of a double stage power architecture where

A. Coccia; F. Canales; H.-R. Riniker; G. Knapp; M. Kalbermatten; M. Baldinger; P. Barbosa

2009-01-01

101

Simple Digital-Controlled AC\\/DC Converter with Power Factor Correction for Universal Input Applications  

Microsoft Academic Search

A simple digital-controlled AC\\/DC converter with power factor correction for universal input applications is presented. The presented method provides the following features: (1). easy for digital implementation, (2). universal input applications, (3). high power factor, (4). fast dynamic response, (5). no need of circuit parameter in prior, (6). no need of input voltage sensor. The range of input voltage for

Ko-Yen Lee; Hsiang-Yu Hsu; Yen-shin Lai

2007-01-01

102

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 consists of a shunt connected source of reactive power, and two series connected voltage­sourced converters shunt connected current­sourced converters around a series connected reactive element. In both cases

Lehn, Peter W.

103

Advanced aerospace power distribution and control techniques.  

NASA Technical Reports Server (NTRS)

Conventional power distribution and control systems as employed in Apollo space vehicles and modern aircraft are reviewed, and arguments are presented in favor of applying some new techniques in the design of electric power systems for future manned spacecraft. Current Space Shuttle studies show that each pound of weight for supporting subsystems causes overall vehicle weight at launch to increase by 34.5 lb, with proportional cost penalty. The presently available technology for an improved automatic or semiautomatic distribution and control system should be implemented. A systems approach based on the most current technology is discussed along with a unique method of system development, testing, and evaluation.

Jeffcoat, T. D.; Eastman, F. E.

1972-01-01

104

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

E-print Network

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

Tidd, Chad N. (Chad Norman)

2010-01-01

105

High efficiency DC/AC power converter for photovoltaic applications  

E-print Network

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

Trubitsyn, Aleksey

2010-01-01

106

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

107

Are power-law distributions an equilibrium distribution or a stationary nonequilibrium distribution?  

NASA Astrophysics Data System (ADS)

We examine whether the principle of detailed balance holds for the power-law distributions that are generated from the well-known two-variable Langevin equation and the associated Fokker-Planck equations. With the detailed balance and the generalized fluctuation-dissipation relation, we derive analytically the stationary power-law distribution from the Ito’s, Stratonovich’s and Zwanzig’s Fokker-Planck equations, and conclude that the power-law distributions can either be a stationary nonequilibrium distribution or an equilibrium distribution, which depend on information about the form of the diffusion coefficient function and the existence and uniqueness of an equilibrium state.

Guo, Ran; Du, Jiulin

2014-07-01

108

Power and Locality Aware Request Distribution  

Microsoft Academic Search

With the growing use of cluster systems in file distribution, web servers and database transactions, efficiency and power optimization have realized a lot of significance. Distributor based systems has been widely adopted, which forward the requests from the clients to a set of waiting balanced servers in complete transparency to the clients. The policy employed in forwarding the requests from

Heungki Lee; Gopinath Vageesan; Eun Jung Kim

109

A Power Electronic-Based Distribution Transformer  

Microsoft Academic Search

The distribution transformer has been in use by utilities throughout the twentieth century. Until now, it has consisted of a configuration of iron or steel cores and copper\\/aluminum coils, with mineral oil serving as both coolant and dielectric medium. Inherent in this type of construction are regulation, significant weight, losses, environmental concerns, and power quality issues. A new kind of

E. R. Ronan; S. D. Sudhoff; S. F. Glover; D. L. Galloway

2002-01-01

110

A power electronic-based distribution transformer  

Microsoft Academic Search

The distribution transformer has been in use by utilities throughout the twentieth century. Until now, it has consisted of a configuration of iron or steel cores and copper\\/aluminum coils, with mineral oil serving as both coolant and dielectric medium. Inherent in this type of construction are regulation, significant weight, losses, environmental concerns, and power quality issues. For the 21st century,

Edward R. Ronan; Scott D. Sudhoff; Steven F. Glover; Dudley L. Galloway

2002-01-01

111

Point of collapse methods applied to ac/dc power systems  

SciTech Connect

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

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

1992-05-01

112

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

113

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

114

Analysis of magnetic field distribution and AC losses of a 600 kJ SMES  

NASA Astrophysics Data System (ADS)

Development of a 600 kJ superconducting magnetic energy storage (SMES) system is being in progress by Korea Electrotechnology Research Institute (KERI). 3-ply BSCCO-2223 wire was considered as a conductor for the winding of the SMES system and auto-tuning niching genetic algorithm was adopted for an optimization method of the HTS magnets in the 600 kJ SMES system. Several constraint conditions were considered for optimal design of HTS magnet of SMES system such as operating current, length of HTS wire in piece, gap between double pancake coils, stored magnetic energy, etc. As a result, output parameters for 6 case designs of 600 kJ SEMS were obtained as optimal design results according to the operating currents. In this research, one of the 6 cases was chosen to analyze magnetic field distribution of the 600 kJ SMES system. AC loss for each double pancake module of SMES during discharge period was also calculated. These HTS windings will be applied to the SMES system whose purpose is stabilization of the power grid.

Park, Myung-Jin; Kwak, Sang-Yeop; Kim, Woo-Seok; Lee, Seung-Wook; Lee, Ji-Kwang; Choi, Kyeong-Dal; Jung, Hyun-Kyo; Seong, Ki-Chul; Hahn, Song-yop

2007-07-01

115

Research on digital controlled converter for AC power electronics burn-in test with Energy Feedback  

Microsoft Academic Search

It is necessary to do burn-in test for many power electric products. Compared to conventional resistor method whose consumption is generally huge, equipments with power recycling function in burn-in test are recognized as more thrifty-not only reduce energy loss but also save manufacturing cost. This paper presents a digital controlled converter for AC power electronics burn-in test with energy feedback,

Yufei Zhou; Lei Wang; Xin Chen

2008-01-01

116

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

NASA Astrophysics Data System (ADS)

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

Morell, Wilbert J., III

1995-05-01

117

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

NASA Astrophysics Data System (ADS)

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

Morrell, Wilbert J., III

1994-10-01

118

A Stabilization of Frequency Oscillations in a Parallel AC-DC Interconnected Power System via an HVDC Link  

Microsoft Academic Search

This paper presents a new application of High Voltage Direct Current (HVDC) link to stabilization of frequency oscillations in a parallel AC-DC interconnected power system. When an interconnected AC power system is subjected to a large load with rapid change, system frequency may be considerably disturbed and becomes oscillatory. By utilizing the system interconnections as the control channels of HVDC

Issarachai Ngamroo

2002-01-01

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

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

121

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

2012-06-07

122

Effect of an AC magnetic field on the steady-state magnetization distribution in a weak ferromagnet  

Microsoft Academic Search

Possible steady-state magnetization distributions in a domain wall are found in a weak ferromagnet subjected to an ac magnetic\\u000a field. The character of the rotation of the magnetization vector in the domain wall is determined. It is predicted that domain\\u000a structures can be rearranged and reoriented under an ac magnetic field.

V. S. Gerasimchuk; A. A. Shitov

2008-01-01

123

Intelligent distributed control for nuclear power plants  

Microsoft Academic Search

In September of 1989 work began on the DOE University Program grant DE-FG07-89ER12889. The grant provides support for a three year project to develop and demonstrate Intelligent Distributed Control (IDC) for Nuclear Power Plants. The body of this Second Annual Technical Progress report covers the period from September 1990 to September 1991. It summarizes the second year accomplishments while the

E. H. Klevans; R. M. Edwards; A. Ray; K. Y. Lee; J. A. Turso; A. BenAbdennour

1991-01-01

124

Damping of a parallel AC-DC power system using PID power system stabilizers and rectifier current regulators  

Microsoft Academic Search

A scheme for improving the dynamic stability of a parallel AC-DC power system is presented. It uses a proportional-integral-derivative (PID) power-system stabilizer and a PID rectifier current regulator to enhance the damping for the electromechanical mode of the system. The parameters of the proposed PID controllers are determined using a unified approach based on modal control theory. Eigenvalue analyses are

Yuan-Yih Hsu; L. Wang

1988-01-01

125

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

NASA Technical Reports Server (NTRS)

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

Schmeckpeper, K. R.

1987-01-01

126

A high performance single phase AC to DC rectifier with input power factor correction  

Microsoft Academic Search

A high performance single phase AC to DC rectifier with input power factor correction is proposed. The proposed approach has many advantages which include fewer semiconductor components, simplified control, high performance features and satisfaction of IEC 555 harmonic current standards. Simulation and experimental results obtained on a laboratory prototype are discussed

P. N. Enjeti; R. Martinez

1993-01-01

127

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

128

Motor power control circuit for ac induction motors  

NASA Astrophysics Data System (ADS)

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

Nola, F. J.

1983-03-01

129

Long-Lifetime Power Inverter for Photovoltaic AC Modules  

Microsoft Academic Search

This paper presents a power inverter tailored for low-power photovoltaic (PV) systems. The inverter features high reliability, thanks to a circuit topology that obviates aluminum electrolytic capacitors from the circuit. Moreover, all components, including logic and control, have been designed to exhibit high reliability at high temperatures. Three conversion stages form the power topology. First, a full bridge connected to

Cuauhtemoc Rodriguez; Gehan A. J. Amaratunga

2008-01-01

130

Motor power control circuit for ac induction motors  

NASA Technical Reports Server (NTRS)

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

Nola, F. J. (inventor)

1983-01-01

131

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

132

Novel AC-DC\\/DC-AC, DC-AC\\/AC-DC and AC-AC macrocommutators for intelligent main battle tank propulsion and dispulsion  

Microsoft Academic Search

One of the trends in integrated high- and medium-power electronics (macroand mesoelectronics) in transportation is towards novel AC-DC\\/DC-AC, DC-AC\\/AC-DC and AC-AC macrocommutators for electrically-powered and mechatronically-controlled intelligent main battle tank propulsion and dispulsion spheres, incorporating two automotive gas turbo- autoabsorb- or autodriveable flywheels that are based on the Fijalkowski turbine boosting system with the brushless AC commutatorless or AC-DC\\/DC-AC macrocommutator

Bogdan T. Fijalkowski

1996-01-01

133

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.

134

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

135

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

Microsoft Academic Search

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

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

2010-01-01

136

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

137

Full-chip verification methods for DSM power distribution systems  

Microsoft Academic Search

Power distribution verification is rapidly becoming a necessary step in deep submicron (DSM) design of high performance integrated circuits. With the increased load and reduced tolerances of DSM circuits, more failures are being seen due to poorly designed power distribution systems. This paper describes an efficient approach for the verification of power distribution at the full-chip transistor level based on

Gregory Steele; David Overhauser; Steffen Rochel; Syed Zakir Hussain

1998-01-01

138

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

139

Electric power processing, distribution, management and energy storage  

NASA Technical Reports Server (NTRS)

Power distribution subsystems are required for three elements of the SPS program: (1) orbiting satellite, (2) ground rectenna, and (3) Electric Orbiting Transfer Vehicle (EOTV). Power distribution subsystems receive electrical power from the energy conversion subsystem and provide the power busses rotary power transfer devices, switchgear, power processing, energy storage, and power management required to deliver control, high voltage plasma interactions, electric thruster interactions, and spacecraft charging of the SPS and the EOTV are also included as part of the power distribution subsystem design.

Giudici, R. J.

1980-01-01

140

DC/AC Student Guide: Solar Energy Power System  

NSDL National Science Digital Library

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

2014-08-28

141

Spectral and Power Stability Tests of Deep UV LEDs for AC Charge Management  

NASA Astrophysics Data System (ADS)

Deep ultraviolet (UV) LEDs have recently been used in AC charge management experiments to support gravitational reference sensors for future space missions. The UV LED based charge management system offers compact size, light weight, and low power consumption compared to plasma sources. The AC charge management technique, which is enabled by easy modulation of UV LED output, achieves higher dynamic range for charge control. Further, the high modulation frequency, which is out of the gravitational wave detection band, reduces disturbances to the proof mass. However, there is a need to test and possibly improve the lifetime of UV LEDs, which were developed only a year ago. We have initiated a series of spectral and power stability tests for UV LEDs and designed experiments according to the requirements of AC charge management. We operate UV LEDs with a modulated current drive and maintain the operating temperature at 22 °C,28 similar to the LISA spacecraft working condition. The testing procedures involve measuring the baseline spectral shape and output power level prior to the beginning of the tests and then re-measuring the same quantities periodically. As of the date of submission (August 28th, 2006), we have operated a UV LED for more than 2,700 hours.

Sun, Ke-Xun; Higuchi, Sei; Goh, Allex; Allard, Brett; Gill, Dale; Buchman, Saps; Byer, Robert

2006-11-01

142

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

143

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

144

Theoretical and Experimental Analysis of AC Loss Characteristic of Bifilar Pancake Coil With Coated Conductor  

Microsoft Academic Search

According to recent studies, economical feasibility of resistive superconducting fault current limiters (FCLs) in transmission and distribution power line is confirmed. Since the SFCL is operated under alternating current (AC), it causes power loss, so-called AC loss, during normal operation condition even though it is superconductor. Bifilar pancake winding with coated conductor (CC) is expected to reduce AC loss of

Dong Keun Park; Joo Seok Bang; Seong Eun Yang; Tae Kuk Ko; Yong Soo Yoon; Min Cheol Ahn; Kideok Sim

2008-01-01

145

The universal power electronics based distribution transformer, an unified approach  

Microsoft Academic Search

A high frequency switched, power electronics based distribution transformer is introduced and described. Besides the definition of appropriate voltage and power ratings also several preferred topologies are discussed, favorable to replace the typical power frequency distribution transformer by a high frequency switched one with low number of variants. Special attention is paid to modularity and automated production capability of all

Lothar Heinemann; Gerhard Mauthe

2001-01-01

146

Low power distributed MAC for ad hoc sensor radio networks  

Microsoft Academic Search

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

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

2001-01-01

147

Automation in the Space Station module power management and distribution Breadboard  

NASA Technical Reports Server (NTRS)

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

Walls, Bryan; Lollar, Louis F.

1990-01-01

148

Distributed energy store powered railguns for hypervelocity launch  

NASA Astrophysics Data System (ADS)

Highly distributed power supplies are proposed as a basis for current difficulties with hypervelocity railgun power-supply compactness. This distributed power supply configuration reduces rail-to-rail voltage behind the main armature, thereby reducing the tendency for secondary armature current formation; secondary current elimination is essential for achieving the efficiencies associated with muzzle velocity above 6 km/sec. Attention is given to analytical and experimental results for two distributed energy storage schemes.

Maas, Brian L.; Bauer, David P.; Marshall, Richard A.

1993-01-01

149

Applications of an electronic transformer in a power distribution system  

E-print Network

In electrical power distribution and power electronic applications, a transformer is an indispensable component which performs many functions. At its operating frequency (60/50 Hz), it is one of the most bulky and expensive components. The concept...

Ratanapanachote, Somnida

2005-11-01

150

14 CFR 23.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2013 CFR

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2013-01-01

151

14 CFR 23.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2012 CFR

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2012-01-01

152

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2011 CFR

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2011-01-01

153

14 CFR 23.1310 - Power source capacity and distribution.  

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2014-01-01

154

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2012 CFR

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2012-01-01

155

14 CFR 25.1310 - Power source capacity and distribution.  

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2014-01-01

156

14 CFR 25.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2013 CFR

...in any one power supply system, distribution system, or other utilization system. (b) In determining...of this section, the power loads may be assumed to...Loads not required in controlled flight need not be...

2013-01-01

157

Gastric MUC5AC and MUC6 are large oligomeric mucins that differ in size, glycosylation and tissue distribution.  

PubMed Central

Gastric MUC5AC and MUC6 mucins were studied using polyclonal antibodies. Immunohistochemistry showed MUC5AC to originate from the surface epithelium, whereas MUC6 was produced by the glands. Mucins from the surface epithelium or glands of corpus and antrum were purified using CsCl/4M guanidinium chloride density-gradient centrifugation. MUC5AC appeared as two distinct populations at 1.4 and 1.3 g/ml, whereas MUC6, which was enriched in the gland tissue, appeared at 1.45 g/ml. Reactivity with antibodies against the Le(b) structure (where Le represents the Lewis antigen) followed the MUC5AC distribution, whereas antibodies against the Le(y) structure and reactivity with the GlcNAc-selective Solanum tuberosum lectin coincided with MUC6, suggesting that the two mucins are glycosylated differently. Rate-zonal centrifugation of whole mucins and reduced subunits showed that both gastric MUC5AC and MUC6 are oligomeric glycoproteins composed of disulphide-bond linked subunits and that oligomeric MUC5AC was apparently smaller than MUC6. A heterogeneous population of 'low-density' MUC5AC mucins, which were smaller than the 'high-density' ones both before and after reduction, reacted with an antibody against a variable number tandem repeat sequence within MUC5AC, suggesting that they represent precursor forms of this mucin. Following ion-exchange HPLC, both MUC5AC and MUC6 appeared as several distinct populations, probably corresponding to 'glycoforms' of the mucins, the most highly charged of which were found in the gland tissue. PMID:11988092

Nordman, Henrik; Davies, Julia R; Lindell, Gert; de Bolós, Carme; Real, Francisco; Carlstedt, Ingemar

2002-01-01

158

Distributed Power Generation: Requirements and Recommendations for an ICT Architecture  

E-print Network

possible to generate energy efficiently in large-scale power plants, a complex infrastructure is needed as the final storage of the conversion products in the nuclear power case imply severe environmental problems production and distribution costs [1]. Unlike consumption power, balance power is not used to operate elec

Appelrath, Hans-Jürgen

159

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

160

PowerAntz: Ant behavior inspired power budget distribution scheme for Network-on-Chip systems  

Microsoft Academic Search

In Network-on-Chip (NoC) based complex system design on-chip power management is a challenging issue. Most power management schemes fail to provide optimal power sharing among on-chip routers when the power budget distribution varies significantly due to their non-uniform placement on chip. This paper presents PowerAntz, an ant system inspired distributed power management strategy for NoC based systems. This is an

Suman Kalyan Mandal; Rabi N. Mahapatra

2010-01-01

161

Developments in space power components for power management and distribution  

NASA Technical Reports Server (NTRS)

Advanced power electronic components development for space applications is discussed. The components described include transformers, inductors, semiconductor devices such as transistors and diodes, remote power controllers, and transmission lines.

Renz, D. D.

1984-01-01

162

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

163

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

164

ac losses and field and current density distribution during a full cycle of a stack of superconducting tapes  

NASA Astrophysics Data System (ADS)

Starting from an existing model by Clem et al., this paper has analyzed how the current density and magnetic field distribution of a stack of superconducting tapes with ac transport currents or applied fields will change in a full cycle. This paper assumes when the ac current or field starts to change in the other direction, a new penetrated region will begin to penetrate from the superconductor surface. If we assume Jc is constant in the critical region, this paper demonstrates that the Claassen formula (7) can be used to calculate the exact ac losses. If Jc depends on local Bz, we can use Eq. (9) to quickly predict the ac losses. This approach does not need to calculate a complete ac cycle. This saves considerably computation time while gives a result which is in close agreement with that calculated from a complete ac cycle. The calculation method can be applied for calculating a superconducting pancake coil if the coil radius is much larger than the tape width.

Yuan, Weijia; Campbell, A. M.; Coombs, T. A.

2010-05-01

165

Local Control of Reactive Power by Distributed Photovoltaic Generators  

Microsoft Academic Search

High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may 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. Fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage

Konstantin S. Turitsyn; Petr Sulc; Scott Backhaus; Misha Chertkov

2010-01-01

166

Evaluation of the power of the distributed blast type explosive  

Microsoft Academic Search

Many works have been done on power evaluation of explosives and some evaluation methods presented. However, because of the differences of the explosion characteristics between distributed blast and common condensed explosive, a more reasonable way for evaluating the power of distributed blast is needed. In the paper, for a given range in space, a TNT equivalency method is proposed. Both

Huang Rui; Yang Lizhong; Chen Wanghua; Liu Jiacong; Fan Weicheng

2002-01-01

167

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

168

Power and Weight Distribution Design Criteria for Cooperative Diversity Channels  

Microsoft Academic Search

The paper considers the single relay orthogonal cooperative diversity decode and forward scenario as a block fading channel model. A closed form expression for the pairwise error probability is derived which leads to design criteria for full diversity and coding gain. Furthermore, the power distribution between the source and relay units is introduced as a design parameter. Fixed power distribution

Paul Lusina; Robert Schober; Lutz Lampe

2007-01-01

169

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

170

Sequentially controlled distributed solar-array power system with maximum power tracking  

Microsoft Academic Search

Presented herein is the sequentially controlled distributed solar-array power system with maximum power tracking (MPT). The power system controller sequentially activates sufficient solar-array sourced dc-dc converter power-processing channels, of which paralleled-outputs supply power to a common load. A \\

Kasemsan Siri; Kenneth A. Conner

2004-01-01

171

IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 7, NO. 2, MAY 1992, PP. 673 683. POINT OF COLLAPSE METHODS APPLIED TO AC DC POWER SYSTEMS  

E-print Network

to determine the distance in state space to the point of collapse, so that better estimates of the loadabilityIEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 7, NO. 2, MAY 1992, PP. 673 683. POINT OF COLLAPSE METHODS APPLIED TO AC DC POWER SYSTEMS Claudio A. Ca~nizares Fernando L. Alvarado Christopher L. DeMarco Ian

Cañizares, Claudio A.

172

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

173

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

174

Power and Conflict in Jordanian Food Distribution Channels  

Microsoft Academic Search

The purpose of this study is to examine power and conflict relationshios in food distribution channels in Jordan. A random sample of 178 food retailers has been selected from three major cities in Jordan. The results of the analyses indicate that food retailers attribute more power to those wholesalers who provide high quality assistances (noncoercive power sources) and who are

Raef T. A. Hussein; Robert A. Robicheaux

1990-01-01

175

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

176

Distributed simulation for power system analysis including shipboard systems  

Microsoft Academic Search

Power systems are distributed in nature. Often they can be divided into sections or groups and treated separately. Terrestrial power systems are divided into separate utilities and are controlled by different regional transmission organization (RTO). Each RTO has detailed data for the area under its control, but only limited data and boundary measurements of the external network. Additionally, shipboard power

Jian Wu; Noel N. Schulz; Wenzhong Gao

2007-01-01

177

Distributed power-a solution for the 90s  

Microsoft Academic Search

The telecommunication industry has witnessed several major technological changes within the system equipment, architectures and the operating topologies. For power equipment vendors however, it is only with the trend towards network decentralization that system or equipment changes have triggered interest for different approaches to powering. This paper presents a distributed power plant (DPP) architecture which can be deployed effectively in

B. Ashdown; J. Poulin

1993-01-01

178

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

179

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

180

f-beta Power Spectrum and Stable Distribution  

Microsoft Academic Search

The fractional integral of white noise produces a fractal fluctuation with a f-beta power spectrum. By generalizing Holtzmark's method, we can exactly calculate the distribution function of the fluctuation. The obtained distribution is the Levy's stable distribution of which the characteristic exponent is a simple function of beta. This result may give a new insight to the basic study of

Hideki Takayasu

1987-01-01

181

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

NASA Astrophysics Data System (ADS)

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

Öberg, Tomas; Peltola, Pasi

2009-12-01

182

A New Power Flow Method in Radial Distribution Systems  

NASA Astrophysics Data System (ADS)

In this paper, a new efficient method is proposed for power flow calculation in radial distribution systems. The distribution busines is changing the need to plan and respond to technical change, growth in distributed generation and deregulated power markets. Thus, it is important to improve fundamental analytical tools in distribution systems. This paper proposes a new method for the power flow calculation in distribution systems. The Newton-Raphson method does not work in some distribution systems. As a result, DistFlow that focuses on the network topology was developed to overcome the problem. However, there is still room for improvement in terms of computational efficiency. In this paper, a method is proposed to improve the efficiency in creating the Jacobian.

Ohyoshi, Wataru; Mori, Hiroyuki

183

Power Transmission Control Using Distributed Max Flow  

Microsoft Academic Search

Existing maximum flow algorithms use one proces- sor for all calculations or one processor per vertex in a graph to calculate the maximum possible flow through a graph's vertices. This is not suitable for practical implementation. We extend the max-flow work of Goldberg and Tarjan to a distributed algorithm to calculate maximum flow where the number of processors is less

Austin Armbruster; Michael R. Gosnell; Bruce M. Mcmillin; M. L. Crow

2005-01-01

184

Technology spin-off from space power automation to terrestrial electrical power distribution control and operation  

NASA Astrophysics Data System (ADS)

Areas which hold potential for technology spin-off from space power automation into terrestrial electrical power distribution control and automation are investigated. Areas touched upon include load management, loss reduction, trend analysis, energy storage, and fault diagnosis and analysis with expert systems. A brief overview of terrestrial electric power technology and automation in terrestrial distribution is provided. Power handling capabilities, hardware, loads, and goals of terrestrial and space systems are compared.

Callis, C. T.; Broadwater, R. P.; Chandrasekaran, A.

185

Air ion mobility spectra and concentrations upwind and downwind of overhead AC high voltage power lines  

NASA Astrophysics Data System (ADS)

Corona ions produced by high-voltage power lines (HVPLs) can alter the nearby electrical environment, potentially increasing aerosol charge levels downwind. However, there is a lack of knowledge concerning the concentration and mobility of ions from AC HVPLs and their dispersion away from the line. We present ion concentration and mobility measurements made near AC HVPLs in South-West England. Examples of typical mobility spectra are shown highlighting features commonly observed. Corona was observed during 33 of 46 measurements, at 9 of 11 sites, with positive or ‘bipolar' (both polarities) ion production commonly seen. Ion production usually increases atmospheric concentrations by only a modest amount, but extreme cases can enhance concentration by an order of magnitude or more. A polarity imbalance is required to increase aerosol charge via ion attachment; this was observed on 15 of 24 days when positive corona was observed, but was not seen for negative ions. Ion mobility was higher downwind compared with upwind for both ion polarities, but the increase was not statistically significant. Future work should focus on identifying and characterising ‘heavy-producing' HVPLs, and obtaining results in conditions which may favour negative ion production e.g. high humidity, inclement weather or during nighttime.

Wright, Matthew D.; Buckley, Alison J.; Matthews, James C.; Shallcross, Dudley E.; Henshaw, Denis L.

2014-10-01

186

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

187

Comprehensive Diagnosis of Complex Electrical Power Distribution Systems  

E-print Network

Comprehensive Diagnosis of Complex Electrical Power Distribution Systems Indranil Roychoudhury subsystems. This heterogeneity introduces significant challenges for model-based diagnosis, such as building and modeling errors. In this paper, we present a comprehensive methodology for the diagnosis of parametric

Daigle, Matthew

188

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

189

On the Packet Delay Distribution in Power-Law Networks  

Microsoft Academic Search

Measurement studies of the Internet topology have revealed that the degree distribution exhibits a power-law attribute. That is, the probability P(k) that a node has k outgoing links follows P(k) ~ k-gamma. However, it is known that the power-law degree distribution alone does not determine traffic-level behaviors in Internet topologies. In this paper, we investigate packet-level delay behavior of topologies

Takahiro Hirayama; S. Arakawa; K.-i. Arai; M. Murata

2009-01-01

190

System Design of Compact Low-Power Inverters for the Applica- tion in Photovoltaic AC-Modules  

Microsoft Academic Search

Photovoltaic ac-modules may become a future trend in PV system technology. For a reliable integration of the power electronic converter into the PV panel (also called PV module) the thermal mission profile of the photo- voltaic system has to be analysed. In this paper, a mechatronic integration strategy is introduced and a thermal test setup is presented showing the need

Benjamin Sahan; Norbert Henze; Alfred Engler; Peter Zacharias; Thomas Licht

191

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

192

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

193

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

194

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

195

Hierarchical Power Distribution with 20 Power Domains in 90-nm Low-Power Multi-CPU Processor  

Microsoft Academic Search

Hierarchical power distribution using a power tree is developed. It supports fine-grained power gating with dozens of power domains like fine-grained clock gating and effectively reduces leakage currents for 1-million-gate power domains to 1\\/4000 in multi-CPU processors with minimal area overhead. This paper demonstrates the integration of 20 power domains in a 90nm single-chip 3G cellular phone processor

Y. Kanno; H. Mizuno; Y. Yasu; K. Hirose; Y. Shimazaki; T. Hoshi; Y. Miyairi; T. lshii; T. Yamada; T. Irita; T. Hattori; K. Yanagisawa; N. lrie

2006-01-01

196

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.

2009-11-11

197

Azimuthal Distribution of ULF Wave Power in the Magnetosphere  

NASA Astrophysics Data System (ADS)

The Van Allen radiation belts contain highly energetic particles which interact with a variety of plasma and MHD waves. ULF waves play an important role in loss and acceleration of energetic particles. There is still much to be understood about the interaction between charged particles and ULF waves and how these waves influence diffusion of charged particles. We will investigate how ULF wave power distribution in azimuth affects radial diffusion of charged particles. We will present results from CRRES (Combined Release and Radiation Effect Satellite) magnetometer data study regarding the azimuthal distribution of wave power in the geomagnetic field. Current theoretical treatments of radial diffusion assume a constant power distribution in azimuth while our results show that this is clearly not the case. Our ongoing investigation includes further study of azimuthal distribution of wave power as well as the distribution of wave power across different mode numbers. In order to use the in situ point measurements such as from a spacecraft, it is necessary to assume that all of the wave power exists in the first mode. But how valid is this assumption? How much power is contained in the higher modes? These are some of the questions we wish to investigate as a part of our ongoing study to better our understanding of particle dynamics in the magnetosphere.

Ali, A.; Elkington, S. R.

2013-12-01

198

62. View of amplifiermodulator control system with power distribution panel ...  

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

62. View of amplifier-modulator control system with power distribution panel on left, control power supply in middle, and amplifier modulator on right, second floor in transmitter building no. 102. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

199

Power-law mass distribution of aggregation systems with injection  

Microsoft Academic Search

We introduce a new family of aggregation models with constant interjection. In our models, the asymptotic distribution of particle mass, s, always follows a power law, P(>=s)~s-alpha, where (1\\/3<=alpha<= 1) \\/ 2 . It is clarified that this power law is realized by a balance of two effects, injection and aggregation.

Hideki Takayasu; Ikuko Nishikawa; Hal Tasaki

1988-01-01

200

Influence of Subsea Cables on Offshore Power Distribution Systems  

Microsoft Academic Search

Subsea cable applications for the offshore power distribution systems create technical challenges in the system design, operation and maintenance. Harmonic parallel resonance introduced by subsea cables is one of the main concerns. In this paper, parallel resonance is investigated for an offshore distribution system with lengthy subsea cables on four interconnected platforms. Variable frequency drives are the dominant loads on

Xiaodong Liang; William Jackson

2008-01-01

201

Influence of Subsea Cables on Offshore Power Distribution Systems  

Microsoft Academic Search

Subsea cable applications for the offshore power distribution systems create technical challenges in the system design, operation, and maintenance. Harmonic parallel resonance introduced by subsea cables is one of the main concerns. In this paper, parallel resonance is investigated for an offshore distribution system with lengthy subsea cables on four interconnected platforms. Variable frequency drives (VFDs) are the dominant loads

Xiaodong Liang; William Michael Jackson

2009-01-01

202

An AC-to-DC Converter with Improved Input Power Factor and High Power Density  

Microsoft Academic Search

A novel single-phase switch-mode rectifier (SMR) structure is proposed and analyzed. The proposed converter structure employs a synchronous front-end rectifier (SFER) stage which provides high-quality input characteristics with small input filtering. Consequently the proposed converter structure exhibits high power density and has low implementation cost.

Stefanos Manias; Phoivos D. Ziogas; Guy Olivier

1986-01-01

203

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

204

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

205

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

206

Options for Control of Reactive Power by Distributed Photovoltaic Generators  

E-print Network

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

Petr Sulc; Konstantin Turitsyn; Scott Backhaus; Michael Chertkov

2010-08-04

207

AC to DC power converter and method with integrated line current control for improving power factor  

SciTech Connect

This patent describes a power converter for converting alternating line current provided at an input to direct current delivered at an output of the power converter. It comprises: filtering means for filtering the input alternating line current, rectifying means responsive to the input current filtering means for rectifying the filtered input line current, direct current control means, operated at a substantially higher frequency than the frequency of the input alternating line current, for controlling the direct current delivered to the output of the power converter. The direct current control means particularly comprising current switching means for switching the filtered and rectified line current at high frequency and a control circuit for providing a control signal output for controlling the current switching means and an integrating means, line current sensing means, responsive to an output of the current rectifying means, for sensing the filtered and rectified line current and the integrating means responsive to the line current sensing means and to the control signal output of the control circuit of the direct current control means for integrating the sensed line current and for providing a first control signal input to the control circuit of the direct current control means.

Severinsky, A.J.

1990-07-24

208

Power distribution practices in USA and Europe: impact on power quality  

Microsoft Academic Search

Design practices for electric power distribution systems in USA and Europe are compared and the differences are identified. The differences have a profound impact on several aspects such as safety, protection and power quality. This paper concentrates on the impact of the European and USA practice on power quality. The paper reviews the design practices in the USA and in

A. P. Sakis Meliopoulos; John Kennedy; C. A. Nucci; A. Borghetti; George Contaxis

1998-01-01

209

Industrial Power Distribution System Reliability Assessment utilizing Markov Approach  

NASA Astrophysics Data System (ADS)

A method to perform power system reliability analysis using Markov Approach, Reliability Block Diagrams and Fault Tree analysis has been presented. The Markov method we use is a state space model and is based on state diagrams generated for a one line industrial power distribution system. The Reliability block diagram (RBD) method is a graphical and calculation tool used to model the distribution power system of an industrial facility. Quantitative reliability estimations on this work are based on CARMS and Block Sim simulations as well as state space, RBD's and Failure Mode analyses. The power system reliability was assessed and the main contributors to power system reliability have been identified, both qualitatively and quantitatively. Methods to improve reliability have also been provided including redundancies and protection systems that might be added to the system in order to improve reliability.

Guzman-Rivera, Oscar R.

210

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

211

Distributed power supply with power factor correction: A solution to feed all modules in power electronic transformers  

Microsoft Academic Search

The idea of power electronic transformer (PET), which works with solid-state switches, has been considered noticeably recently. Every power electronic transformer has several parts which each of them needs its own reliable supply voltage. So the appropriate performance of a PET depends on the existence of various proper supply voltages. The distributed power supply (DPS), which can produce several different

M. Saghaleini; S. Farhangi

2007-01-01

212

Power law tails in the Italian personal income distribution  

NASA Astrophysics Data System (ADS)

We investigate the shape of the Italian personal income distribution using microdata from the Survey on Household Income and Wealth, made publicly available by the Bank of Italy for the years 1977-2002. We find that the upper tail of the distribution is consistent with a Pareto-power law type distribution, while the rest follows a two-parameter lognormal distribution. The results of our analysis show a shift of the distribution and a change of the indexes specifying it over time. As regards the first issue, we test the hypothesis that the evolution of both gross domestic product and personal income is governed by similar mechanisms, pointing to the existence of correlation between these quantities. The fluctuations of the shape of income distribution are instead quantified by establishing some links with the business cycle phases experienced by the Italian economy over the years covered by our dataset.

Clementi, F.; Gallegati, M.

2005-05-01

213

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

NASA Astrophysics Data System (ADS)

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

Abdollahi, Rohollah

2012-12-01

214

DETERMINATION OF INVENTORIES AND POWER DISTRIBUTIONS FOR THE NSBR.  

SciTech Connect

This memo presents the details of the methodology for developing fuel inventories for the NBSR along with power distributions predicted with this set of inventories. Several improvements have been made to the MCNP model of the NBSR since a set of calculations was performed in 2002 in support of the NBSR relicensing and SAR update. One of the most significant changes in the model was to divide the fuel elements into upper and lower halves so the effects of uneven burn between the two halves (due to the shim arms) can be determined. The present set of power distributions are provided for comparison with the previous safety analyses.

HANSON, A.L.; DIAMOND, D.J.

2005-09-12

215

Electric power scheduling - A distributed problem-solving approach  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

216

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

2014-04-28

217

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

NASA Astrophysics Data System (ADS)

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

Inoue, Jun; Fujii, Yasumasa

218

Power-law time distribution of large earthquakes.  

PubMed

We study the statistical properties of time distribution of seismicity in California by means of a new method of analysis, the diffusion entropy. We find that the distribution of time intervals between a large earthquake (the main shock of a given seismic sequence) and the next one does not obey Poisson statistics, as assumed by the current models. We prove that this distribution is an inverse power law with an exponent mu=2.06+/-0.01. We propose the long-range model, reproducing the main properties of the diffusion entropy and describing the seismic triggering mechanisms induced by large earthquakes. PMID:12786049

Mega, Mirko S; Allegrini, Paolo; Grigolini, Paolo; Latora, Vito; Palatella, Luigi; Rapisarda, Andrea; Vinciguerra, Sergio

2003-05-01

219

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

220

Application of optical communications for power distribution companies  

Microsoft Academic Search

Optical fibers used in electric power distribution companies are described. There are two kinds of optical fibers used along with grounding wires; one is called the built-in type, in which optical fibers are inserted in the core part of one grounding wire, and one other is called the winding type, in which the optical fiber cable is wound around existing

H. Murata

1990-01-01

221

FUTURE POWER GRID INITIATIVE Modeling of Distributed Energy  

E-print Network

, and » validation and uncertainty quantification Validation will compare the results from the aggregated model include state transition model and Dynamic Bayesian Network. IMPACT Models representingFUTURE POWER GRID INITIATIVE Modeling of Distributed Energy Resources in the Smart Grid OBJECTIVE

222

An architecture for a power-aware distributed microsensor node  

Microsoft Academic Search

Networks of distributed microsensors are emerging as a compelling solution for a wide range of data gathering applications. Perhaps the most substantial challenge facing designers of small but long-lived microsensor nodes is the need for significant reductions in energy consumption. We propose a power-aware design methodology that emphasizes the graceful scalability of energy consumption with factors such as available resources,

Rex Min; Manish Bhardwaj; Seong-Hwan Cho; Amit Sinha; Eugene Shih; Alice Wang; Anantha Chandrakasan

2000-01-01

223

COMMUNICATION SYSTEMS AND STUDY METHOD FOR ACTIVE DISTRIBUTION POWER SYSTEMS  

E-print Network

of Intelligent Electronic Devices (IED) in modern distributed power system need to exchange large amount of information for system monitoring, protection and control. Therefore the alternative communication techniques toward Smart Grid, which means an electricity network that can intelligently integrate the actions of all

Chen, Zhe

224

Struggle over the pie? The gendered distribution of power and  

E-print Network

. Some policy implications are also discussed. Keywords: gender differences, household bargaining, income of different genders have on the decisions that their households make and the effect that this hasStruggle over the pie? The gendered distribution of power and subjective financial well

de Gispert, Adrià

225

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

226

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

227

General Formulation for Force Distribution in Power Grasp  

Microsoft Academic Search

A general formulation of the force distribution equations for three-dimensional power grasp is presented. It allows for any number of contacts on the finger surfaces and the palm. The formulation not only includes the active forces and moments applied at the contacts, but also the passive forces resulting from frictional and geometric constraints, such as wedging effects. A grasp matrix

Khalid Mirza; David E. Orin

1994-01-01

228

Hierarchical microgrid paradigm for integration of distributed energy resources  

Microsoft Academic Search

This paper describes an approach to hierarchical integration of DC and AC microgrids containing distributed energy resources (DERs) into the existing electric power distribution infrastructure. Power electronic interfaces and controls permit the aggregated units at each level to represent themselves to a higher level as a single self-controlled entity (DC or AC, load or generator). At the top level of

Zhenhua Jiang; Roger A. Dougal

2008-01-01

229

Statistical Models of Power-law Distributions in Homogeneous Plasmas  

SciTech Connect

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

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

2011-01-04

230

Exploring empowerment in settings: mapping distributions of network power.  

PubMed

This paper brings together two trends in the empowerment literature-understanding empowerment in settings and understanding empowerment as relational-by examining what makes settings empowering from a social network perspective. Specifically, extending Neal and Neal's (Am J Community Psychol 48(3/4):157-167, 2011) conception of network power, an empowering setting is defined as one in which (1) actors have existing relationships that allow for the exchange of resources and (2) the distribution of network power among actors in the setting is roughly equal. The paper includes a description of how researchers can examine distributions of network power in settings. Next, this process is illustrated in both an abstract example and using empirical data on early adolescents' peer relationships in urban classrooms. Finally, implications for theory, methods, and intervention related to understanding empowering settings are explored. PMID:24213301

Neal, Jennifer Watling

2014-06-01

231

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

232

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

233

Junction current distributions and ac impedances of thin resistive films on semiconductor junctions  

Microsoft Academic Search

Certain aspects of the blocking layer behavior in semiconductor heterojunction lasers can be modeled as a thin resistive film overlaying a semiconductor forward biased junction. The dc behavior of such a model has been studied previously by W. B. Joyce and S. H. Wemple [J. Appl. Phys. 41, 3818 (1970)]. This paper studies the ac aspects of that model, and

G. A. Baraff

1995-01-01

234

Distributed Power Allocation for Vehicle Management Systems Necmiye Ozay Ufuk Topcu Richard M. Murray  

E-print Network

Distributed Power Allocation for Vehicle Management Systems Necmiye Ozay Ufuk Topcu Richard M vehicle management systems- that cooperatively allocate electric power while meeting certain higher level and external environment. A decentralized control problem is posed where each power distribution unit

Murray, Richard M.

235

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

236

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

237

* jafleeman@aep.com EHV AC and HVDC Transmission Working Together to Integrate Renewable Power  

E-print Network

or underground links, where AC connections are difficult or impractical. Underground HVDC can provide easier in many settings. A long term view with a broader planning scope requires coordination and recognition

McCalley, James D.

238

Modeling Uncertainties in Power System by Generalized Lambda Distribution  

NASA Astrophysics Data System (ADS)

This paper employs the generalized lambda distribution (GLD) to model random variables with various probability distributions in power system. In the context of the probability weighted moment (PWM), an optimization-free method is developed to assess the parameters of GLD. By equating the first four PWMs of GLD with those of the target random variable, a polynomial equation with one unknown is derived to solve for the parameters of GLD. When employing GLD to model correlated multivariate random variables, a method of accommodating the dependency is put forward. Finally, three examples are worked to demonstrate the proposed method.

Xiao, Qing

2014-06-01

239

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

240

Method for Improving Power Quality in Distribution System by Static Capacitors based on Power Line Loss  

NASA Astrophysics Data System (ADS)

Recent rapid introduction of photovoltaic power generations (PVs) causes several issues of power quality. First, reverse flow causes voltage rise of distribution lines. Second, since almost of residential PVs are connected to the distribution lines by single-phase, voltage imbalance is occurred by imbalance current of PVs. On the other hand, in Japan, almost high voltage consumers set up Static capacitors (SCs) to improve the power factor at their receiving points. However, the capacity of SC becomes excessive than required amount of capacity. Hence, the excessive amount of SCs may also cause voltage rise and harmonic voltage problems that is Ferranti Effect and harmonic resonance between SCs and inductance of lines. Under these backgrounds, the purpose of this study is to propose the new control method of SCs not only improving power factor but also solving power quality problems. The major point of the proposed method is to determine the capacity of three-phase type SCs and single-phase type SCs so as to minimize power loss of distribution line in a limitation condition of each power quality.

Uejima, Hiroaki; Naruse, Taichi; Aoki, Mutsumi; Ukai, Hiroyuki; Kobayashi, Hiroshi

241

Modeling of high power LED illumination distribution using ANN  

Microsoft Academic Search

High power light emitting diodes (HP-LEDs) are more suitable for energy saving applications and have becoming replacing traditional fluorescent and incandescent bulbs for its energy efficient. Therefore, HP-LED lighting has been regarded in the next-generation lighting. In this study, illumination distribution of white color HP-LED was examined and modeled by artificial neural network (ANN) to use at the different lighting

I. Kiyak; V. Topuz; B. Oral

2009-01-01

242

London house prices are power-law distributed  

E-print Network

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

MacKay, Niall

2010-01-01

243

Power-Law Testing for Fault Attributes Distributions  

NASA Astrophysics Data System (ADS)

This paper is devoted to statistical analysis of faults' attributes. The distributions of lengths, widths of damage zones, displacements and thicknesses of fault cores are studied. Truncated power-law (TPL) is considered in comparison with commonly used simple power-law (PL) (or Pareto) distribution. The maximal likelihood and the confidence interval of the exponent for both PL and TPL are estimated by appropriate statistical methods. The Kolmogorov-Smirnov (KS) test and the likelihood ratio test with alternative non-nested hypothesis for exponential distribution are used to verify the statistical approximation. Furthermore, the advantage of TPL is proved by Bayesian information criterion. Our results suggest that a TPL is more suitable for describing fault attributes, and that its condition is satisfied for a wide range of fault scales. We propose that using truncated power laws in general might eliminate or relax the bias related to sampling strategy and the resolution of measurements (such as censoring, truncation, and cut effect) and; therefore, the most reliable range of data can be considered for the statistical approximation of fault attributes.

Kolyukhin, Dmitry; Torabi, Anita

2013-12-01

244

Power Management and Distribution (PMAD) Model Development: Final Report  

NASA Technical Reports Server (NTRS)

Power management and distribution (PMAD) models were developed in the early 1990's to model candidate architectures for various Space Exploration Initiative (SEI) missions. They were used to generate "ballpark" component mass estimates to support conceptual PMAD system design studies. The initial set of models was provided to NASA Lewis Research Center (since renamed Glenn Research Center) in 1992. They were developed to estimate the characteristics of power conditioning components predicted to be available in the 2005 timeframe. Early 90's component and device designs and material technologies were projected forward to the 2005 timeframe, and algorithms reflecting those design and material improvements were incorporated into the models to generate mass, volume, and efficiency estimates for circa 2005 components. The models are about ten years old now and NASA GRC requested a review of them to determine if they should be updated to bring them into agreement with current performance projections or to incorporate unforeseen design or technology advances. This report documents the results of this review and the updated power conditioning models and new transmission line models generated to estimate post 2005 PMAD system masses and sizes. This effort continues the expansion and enhancement of a library of PMAD models developed to allow system designers to assess future power system architectures and distribution techniques quickly and consistently.

Metcalf, Kenneth J.

2011-01-01

245

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

246

Power-law distribution of pressure fluctuations in multiphase flow  

NASA Astrophysics Data System (ADS)

Bubbling fluidized beds are granular systems, in which a deep layer of particles is set in motion by a vertical gas stream, with the excess gas rising as bubbles through the bed. We show that pressure fluctuations in such a system have non-Gaussian statistics. The probability density function has a power-law drop-off and is very well represented by a Tsallis distribution. Its shape is explained through the folding of the Gaussian distribution of pressure fluctuations produced by a monodisperse set of bubbles, onto the actual distribution of bubble sizes in the bed, assuming that bubbles coalesce via a Smoluchowski-type aggregation process. Therefore, the Tsallis statistics arise as a result of bubble polydispersity, rather than system nonextensivity.

Gheorghiu, S.; van Ommen, J. R.; Coppens, M.-O.

2003-04-01

247

Power-law distribution of pressure fluctuations in multiphase flow.  

PubMed

Bubbling fluidized beds are granular systems, in which a deep layer of particles is set in motion by a vertical gas stream, with the excess gas rising as bubbles through the bed. We show that pressure fluctuations in such a system have non-Gaussian statistics. The probability density function has a power-law drop-off and is very well represented by a Tsallis distribution. Its shape is explained through the folding of the Gaussian distribution of pressure fluctuations produced by a monodisperse set of bubbles, onto the actual distribution of bubble sizes in the bed, assuming that bubbles coalesce via a Smoluchowski-type aggregation process. Therefore, the Tsallis statistics arise as a result of bubble polydispersity, rather than system nonextensivity. PMID:12786360

Gheorghiu, S; van Ommen, J R; Coppens, M-O

2003-04-01

248

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

249

An optimal power flow based dispatch model for distributed generation embedded network  

Microsoft Academic Search

The installation of distributed generation (DG) introduces challenges to distribution systems operation. The distribution network operator needs to schedule DG outputs considering some constraints, such as DG characteristics, reactive power control mode of generators, automatic voltage regulation, compensator and power quality standard, etc. Based on an optimal power flow model, this paper proposes a dispatch model for DG embedded distribution

Yufeng Lin; Jin Zhong; Math H. J. Bollen

2010-01-01

250

Flexible AC transmission  

Microsoft Academic Search

The operation and components of the flexible AC transmission system (FACTS) are described. FACTS, designed to overcome the limitations of the present mechanically controlled AC power transmission systems, uses reliable, high-speed power electronic controllers. Its benefits are examined. These include greater control of power, so that it flows on the prescribed transmission routes; secure loading of transmission lines to levels

N. G. Hingorani

1993-01-01

251

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 April to October 2004 reporting period in Task 2.3 (SOFC Scaleup for Hybrid and Fuel Cell Systems) 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''. This study analyzes the performance and economics of power generation systems for central power generation application based on Solid Oxide Fuel Cell (SOFC) technology and fueled by natural gas. The main objective of this task is to develop credible scale up strategies for large solid oxide fuel cell-gas turbine systems. System concepts that integrate a SOFC with a gas turbine were developed and analyzed for plant sizes in excess of 20 MW. 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. Technology gaps and required engineering development efforts were identified and evaluated.

David Deangelis; Rich Depuy; Debashis Dey; Georgia Karvountzi; Nguyen Minh; Max Peter; Faress Rahman; Pavel Sokolov; Deliang Yang

2004-09-30

252

Performance analysis of a high frequency multistage power conversion system  

Microsoft Academic Search

A novel high frequency multistage power conversion system is investigated to harness clean energy from distributed resources. The proposed power conversion system controls the output voltage irrespective of variations in the source voltage frequency. A multi-loop control scheme is proposed for the multistage AC-AC conversion system in order to provide a regulated power supply despite source voltage disturbances. A detailed

Maryclaire Peterson; Brij N. Singh

2008-01-01

253

Application of power electronics to the distribution transformer  

NASA Astrophysics Data System (ADS)

This dissertation describes the design and prototype construction of a novel Solid State Transformer (SST). Conventional distribution transformers are in many ways relics of turn-of-the-century technology. While efficient and inexpensive, their secondary voltage waveforms are tightly coupled to the applied primary voltage waveforms, and primary currents are dictated by the load currents. This can cause power quality problems for both the source and the load. Conventional distribution transformers also have inherent voltage drop which increases with load. Replacement of conventional distribution transformers with solid-state devices could provide control over the magnitudes and waveforms of the load voltage and input current. Self-protection would be a natural byproduct of the controls. At the same time, a solid-state transformer would perform all the functions of conventional devices. Previous efforts to develop a solid-state transformer, including one recently sponsored by the Electric Power Research Institute (EPRI), have been limited and comparatively crude demonstration projects. They did not provide isolation and have proven to be impractical when applied to utility distribution voltage levels. These efforts did, however, provide the level of interest sufficient to encourage design of the practical solid-state transformer described herein and eventual construction of a prototype. In this dissertation, an SST architecture is set forth that is specifically designed to operate at utility distribution voltages. It provides a sinusoidal secondary voltage regardless of the primary voltage waveform, provides a secondary voltage magnitude that is independent of either load current or primary voltage magnitude, and at the same time draws sinusoidal input current which is in phase with the primary voltage regardless of secondary current or primary voltage waveshapes.

Ronan, Edward Robert, Jr.

254

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

255

Instantaneous active and nonactive power control of distributed energy resources with a current limiter  

Microsoft Academic Search

Distributed energy resources (DER) with a power electronics inverter interface can provide both active power and nonactive power simultaneously and independently. A decoupled control algorithm of active power and nonactive power is developed based on the instantaneous active power and nonactive power theory. A current limiter is combined to the control algorithm, and it ensures that the inverter is not

Yan Xu; Huijuan Li; D. Tom Rizy; Fangxing Li; John D. Kueck

2010-01-01

256

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

257

Probability distributions of some power system reliability indices  

E-print Network

1241035 11 ABSTRACT Probability Distributions of Some Power System R e l i a b i l i t y Indices (December 1978) Minn Dip (Diep), B.S., Texas A&M University Co-Chairmen of Advisory Committee: Dr. A. D. Patton Dr. A. K. Ayoub Two power transmission.... ACKNOWLEDGMENTS The author i s espe c i a l l y indebted to Dr. Alton D. Patton f o r his guidance and encouragement. He also wishes to thank Dr. A. K. Ayoub and Dr. L. J . Ringer f o r t h e i r advice. He would l i k e to express his g r a t i tude to the E...

Dip, Minh

2012-06-07

258

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

259

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

260

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 October 2002 to December 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The following activities have been carried out during this reporting period: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} Part-load performance analysis was conducted {lg_bullet} Primary system concept was down-selected {lg_bullet} Dynamic control model has been developed {lg_bullet} Preliminary heat exchanger designs were prepared {lg_bullet} Pressurized SOFC endurance testing was performed

Nguyen Minh; Faress Rahman

2002-12-31

261

Power Scheduling for a Network of Distributed Generators  

NASA Astrophysics Data System (ADS)

Growing concerns over the economic and environmental costs of fossil fuels have spurred renewed interest in the area of renewable energy. The Atlantic Sustainable Power Research Initiative (ASPRI) aims to integrate low- and no-emission technology into Atlantic Canada's energy generation mix. This research focuses on the scheduling of distributed generators to improve their aggregate performance while maintaining a small ecological footprint. Combining renewable units with low-emission units using conventional fuels promises improved profitability and reliability over any single technology. Four Unit Commitment methods have been considered for the Energy Control Center (ECC), one of them novel. The novel solution appears to be the first to successfully solve the static Unit Commitment problem in less than exponential time with respect to the number of units - this is especially important when incorporating numerous distributed generators. The stochastic Unit Commitment problem is also considered in an effort to maximize the advantages of intermittent, renewable generators.

Dupuis, Etienne Jacques

262

Evidence of a Gamma Distribution for Prime Powers  

E-print Network

If the prime numbers are pseudo-randomly distributed, then analogy with quantum systems suggests that counting primes might be modeled by a non-homogeneous Poisson process. Consequently, postulating underlying gamma statistics, more-or-less standard heuristic arguments borrowed from quantum mechanics in the context of functional integration allows to derive analytic expressions of several average counting functions associated with prime numbers. The expressions are certain sums of incomplete gamma functions that are closely related to logarithmic-type integral functions --- which in turn are well-known to give the asymptotic dependence of the various counting functions up to error terms. The relatively broad success of quantum heuristics applied to functional integrals in general along with the excellent numerical accuracy of the analytic expressions for the average counting functions provide strong evidence of a gamma distribution for prime powers.

J. LaChapelle

2013-07-05

263

Predicting the Power Output of Distributed Renewable Energy Resources within a Broad Geographical Region  

E-print Network

Predicting the Power Output of Distributed Renewable Energy Resources within a Broad Geographical potentially dis- tributed renewable energy resources (su years, estimating the power output of in- herently intermittent and potentially distributed renewable

Chalkiadakis, Georgios

264

Uniform current distribution conductor of HTS power cable with variable tape-winding pitches  

Microsoft Academic Search

In the multilayer conductor, the inner layers have higher impedance than the outer layers. As a result, the current concentrates in the outer layers. Our early study showed that its AC losses were reduced to one-tenth by making the current of each layer uniform. From such a point of view, a trial to realize the uniform current distribution was made

S. Mukoyama; K. Miyoshi; H. Tsubouti; T. Yoshida; M. Mimura; N. Uno; M. Ikeda; H. Ishii; S. Honjo; Y. Iwata

1999-01-01

265

Comparison of AC losses, magnetic field\\/current distributions and critical currents of superconducting circular pancake coils and infinitely long stacks using coated conductors  

Microsoft Academic Search

A model is presented for calculating the AC losses, magnetic field\\/current density distribution and critical currents of a circular superconducting pancake coil. The assumption is that the magnetic flux lines will lie parallel to the wide faces of tapes in the unpenetrated area of the coil. Instead of using an infinitely long stack to approximate the circular coil, this paper

Weijia Yuan; A. M. Campbell; Z. Hong; M. D. Ainslie; T. A. Coombs

2010-01-01

266

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

267

Power law distributions and dynamic behaviour of stock markets  

NASA Astrophysics Data System (ADS)

A simple agent model is introduced by analogy with the mean field approach to the Ising model for a magnetic system. Our model is characterised by a generalised Langevin equation = F ? + G ? t where t is the usual Gaussian white noise, i.e.: t t' = 2D? t-t' and t = 0. Both the associated Fokker Planck equation and the long time probability distribution function can be obtained analytically. A steady state solution may be expressed as P ? = exp{ - ? ? - ln G(?)} where ? ? = - F/ G d? and Z is a normalization factor. This is explored for the simple case where F ? = J? + b?2 - c?3 and fluctuations characterised by the amplitude G ? = ? + ? when it readily yields for ?>>?, a distribution function with power law tails, viz: P ? = exp{ 2b?-c?2 /D}. The parameter c ensures convergence of the distribution function for large values of ?. It might be loosely associated with the activity of so-called value traders. The parameter J may be associated with the activity of noise traders. Output for the associated time series show all the characteristics of familiar financial time series providing J < 0 and D | J|.

Richmond, P.

2001-04-01

268

Magnetic properties and AC-losses of superconductors with power law current-voltage characteristics  

Microsoft Academic Search

In many high-Tc superconductors the critical current density jc is an ill-defined quantity due to the smooth current-voltage characteristic. Since jc is the basic parameter entering the critical state model, its application to such materials becomes problematic. In this paper, a theory of magnetic properties and AC-losses in superconductors with smooth current-voltage characteristics is proposed. It is applied to superconductors

Jakob Rhyner

1993-01-01

269

Subsystem Interaction Analysis in Power Distribution Systems of Next Generation Airlifters  

E-print Network

electrically. In other words, electrical power will be utilized for driving aircraft subsystems currently1 Subsystem Interaction Analysis in Power Distribution Systems of Next Generation Airlifters Sriram Chandrasekaran, Douglas K. Lindner, Konstantin Louganski and, Dushan Boroyevich Center for Power Electronics

Lindner, Douglas K.

270

Stable Distributed Power Control with High SIR Target for Cellular Wireless Communication Systems Jiayuan Chen1  

E-print Network

Stable Distributed Power Control with High SIR Target for Cellular Wireless Communication Systems station is needed to control all the links in a cellular system. A good paper on centralized power control systems. In distributed power control (DPC), each base station controls and updates the transmitted powers

Haddadi, Hamed

271

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

272

Three-dimensional base distributed effects of long stripe BJT's: AC effects on input characteristics  

Microsoft Academic Search

The small-signal voltage and current distributed effects in the polysilicon and intrinsic base regions of long stripe bipolar junction transistors (BJT's) at high frequencies are investigated, and simple analytic equations describing the voltage and current distribution in these regions are derived. It is shown that the frequency-dependent debiasing effects in the polysilicon contacts and intrinsic base region change the current

Ming-Yeh Chuang; M. E. Law

1998-01-01

273

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

NSDL National Science Digital Library

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

Brixen, Roy

2014-08-04

274

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

275

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

276

Noise powered amplification in CV quantum key distribution  

E-print Network

Amplification plays a key role in classical communication protocols, where it compensates the unavoidable loss of the signal. However, when we enter the quantum domain this approach starts being problematic as the standard kinds of amplifiers are usually accompanied by excess noise which detrimentally affects the quantum features of used states. Recently, several kinds of "noiseless" amplifiers that do not suffer from this feature have been proposed. Among these amplifiers, one that stands out is the noise powered amplifier, which acts incoherently, amplifying the signal by adding the "right" kind of noise. Here we show that despite the incoherence, which makes the amplifier unsuitable for protocols such as entanglement distillation, the added noise is not a big problem in quantum key distribution tasks and can be in some situations beneficial.

Petr Marek; Radim Filip

2014-07-29

277

SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION  

SciTech Connect

This report summarizes the work performed by Honeywell during the July 2001 to September 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. An internal program kickoff was held at Honeywell in Torrance, CA. The program structure was outlined and the overall technical approach for the program was presented to the team members. Detail program schedules were developed and detailed objectives were defined. Initial work has begun on the system design and pressurized SOFC operation.

Unknown

2002-03-01

278

SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION  

SciTech Connect

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

Kurt Montgomery; Nguyen Minh

2003-08-01

279

Modeling and Simulation of an Asynchronous Generator with AC\\/DC\\/AC Converter Fed RLC Series Circuit in an Isolated Power Generation System  

Microsoft Academic Search

This paper expounds a simulation model of a self-excited asynchronous generator (SEASG) feeding R L load in conjunction with an AC\\/DC\\/AC converter fed RLC series circuit connected at the point of common coupling (PCC). Simulation model of the proposed system have been developed by using Matlab\\/Simulink. The result shows that the effect of RLC series circuit when operated at variable

K. Subramanian; K. K. Ray

2010-01-01

280

Power Law Distributions of Patents as Indicators of Innovation  

PubMed Central

The total number of patents produced by a country (or the number of patents produced per capita) is often used as an indicator for innovation. Here we present evidence that the distribution of patents amongst applicants within many countries is well-described by power laws with exponents that vary between 1.66 (Japan) and 2.37 (Poland). We suggest that this exponent is a useful new metric for studying innovation. Using simulations based on simple preferential attachment-type rules that generate power laws, we find we can explain some of the variation in exponents between countries, with countries that have larger numbers of patents per applicant generally exhibiting smaller exponents in both the simulated and actual data. Similarly we find that the exponents for most countries are inversely correlated with other indicators of innovation, such as research and development intensity or the ubiquity of export baskets. This suggests that in more advanced economies, which tend to have smaller values of the exponent, a greater proportion of the total number of patents are filed by large companies than in less advanced countries. PMID:23227144

O'Neale, Dion R. J.; Hendy, Shaun C.

2012-01-01

281

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

282

Power Law Distributions of Patents as Indicators of Innovation  

E-print Network

The total number of patents produced by a country (or the number of patents produced per capita) is often used as an indicator for innovation. Here we present evidence that the distribution of patents amongst applicants within many OECD countries is well-described by power laws with exponents that vary between 1.66 (Japan) and 2.37 (Poland). Using simulations based on simple preferential attachment-type rules that generate power laws, we find we can explain some of the variation in exponents between countries, with countries that have larger numbers of patents per applicant generally exhibiting smaller exponents in both the simulated and actual data. Similarly we find that the exponents for most countries are inversely correlated with other indicators of innovation, such as R&D intensity or the ubiquity of export baskets. This suggests that in more advanced economies, which tend to have smaller values of the exponent, a greater proportion of the total number of patents are filed by large companies than in...

O'Neale, D R J

2012-01-01

283

Exponential and power-law mass distributions in brittle fragmentation.  

PubMed

Generic arguments, a minimal numerical model, and fragmentation experiments with gypsum disk are used to investigate the fragment-size distribution that results from dynamic brittle fragmentation. Fragmentation is initiated by random nucleation of cracks due to material inhomogeneities, and its dynamics are pictured as a process of propagating cracks that are unstable against side-branch formation. The initial cracks and side branches both merge mutually to form fragments. The side branches have a finite penetration depth as a result of inherent damping. Generic arguments imply that close to the minimum strain (or impact energy) required for fragmentation, the number of fragments of size s scales as s(-(2D-1)/D) f(1) (- (2/lambda)(D) s)+ f(2) (- s(-1 )(0 ) (lambda+ s(1/D) )(D) ), where D is the Euclidean dimension of the space, lambda is the penetration depth, and f(1) and f(2) can be approximated by exponential functions. Simulation results and experiments can both be described by this theoretical fragment-size distribution. The typical largest fragment size s(0) was found to diverge at the minimum strain required for fragmentation as it is inversely related to the density of initially formed cracks. Our results also indicate that scaling of s(0) close to this divergence depends on, e.g., loading conditions, and thus is not universal. At the same time, the density of fragment surface vanishes as L-1, L being the linear dimension of the brittle solid. The results obtained provide an explanation as to why the fragment-size distributions found in nature can have two components, an exponential as well as a power-law component, with varying relative weights. PMID:15447542

Aström, J A; Linna, R P; Timonen, J; Møller, Peder Friis; Oddershede, Lene

2004-08-01

284

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

285

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

286

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

E-print Network

A Better Steam Engine: Designing a Distributed Concentrating Solar Combined Heat and Power System of analysis of Distributed Concentrating Solar Combined Heat and Power (DCS-CHP) systems is a design of a theoretical solar CHP system. Then, we explore the economic and technological impetus for a solar powered

California at Berkeley, University of

287

A game theoretic analysis of distributed power control for spread spectrum ad hoc networks  

Microsoft Academic Search

We consider a distributed power control scheme in a spread spectrum (SS) wireless ad hoc network, in which each user announces a price that reflects his current interference level. Given these prices, we present an asynchronous distributed algorithm for updating power levels, and provide conditions under which this algorithm converges to an optimal power allocation. We relate this algorithm to

Jianwei Huang; Randall A. Berry; Michael L. Honig

2005-01-01

288

Reverse-Link Power Control in CDMA Distributed Antenna Systems Arif Obaid Halim Yanikomeroglu  

E-print Network

= = L j iji 1 ( )1 ( )2 Reverse-Link Power Control in CDMA Distributed Antenna Systems Arif Obaid power control is an essential component of any CDMA system. In conventional cellular systems requirements in a CDMA system that employs power control with a distributed antenna architecture. Computer

Yanikomeroglu, Halim

289

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

290

Neural learning algorithm based power quality enhancement for three phase three wire distribution system utilizing shunt active power filter strategy  

Microsoft Academic Search

This paper explores the application of artificial intelligence on solving the power quality problems by using the shunt active power filter strategy for three phase three wire distribution system. The unit vector template generation control technique is modeled as current controller for the shunt active power filter strategy. The proportional and integral (PI) controller is designed to minimize error between

A. Senthil Kumar; P. Ajay-D-Vimal Raj

2011-01-01

291

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

292

Distributed interactive power system simulator using Web technology  

Microsoft Academic Search

Power-system simulator is considered an essential tool for design, operation, and control of electrical power systems. The nature of power-system enforces its simulation into sophisticated mathematical models and matrix calculations. Consequently, several research efforts were directed to develop numerical techniques that include efficient mathematical methods for various power system problems. Along with these developments, valuable research efforts are directed to

Mamdouh Abdel-Akher; M. K. El-Nemr; W. Abdel-Galil

2010-01-01

293

Improved power quality converter fed permanent magnet AC motor for air-conditioning  

Microsoft Academic Search

This paper presents the performance analysis of interior permanent magnet synchronous motor (IPMSM) fed from improved power quality converter–inverter system as a variable speed drive for air-conditioning (Air-Con). The improved power quality converter (IPQC) makes the input power factor unity and also reduces the total harmonic distortion (THD) of input supply current. This converter consists of two uncontrolled unidirectional and

Bhim Singh; S. S. Murthy; Manoj Kumar

2003-01-01

294

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

E-print Network

s pair of thyratrons which operate s set of relays, The relays connect the power source to a servo control motor on the phase. shifter. Thyratrons ware chosen over ordinary vacmjm tubes because of their ability to control large amounts of power... s pair of thyratrons which operate s set of relays, The relays connect the power source to a servo control motor on the phase. shifter. Thyratrons ware chosen over ordinary vacmjm tubes because of their ability to control large amounts of power...

Francis, Lawrence Gregg

2012-06-07

295

Automatic Switching of AC Power in Larger Telephone Exchanges Equipped with Standby Generating Equipment  

Microsoft Academic Search

A concept of switchgear with drawout air circuit breakers used as transfer equipment between commercial utility power and a stand-by power plant is described. The advantages of drawout type air circuit breakers are discussed over the use of commercially available automatic transfer switches. This applies especially to larger exchanges in metropolitan areas. Pictures of actual installations are included to show

Hermann A. Spicker

1984-01-01

296

Optical and thermodynamic analysis and optimization of a novel solar concentrating system for distributed power generation.  

E-print Network

??A novel central receiver power system utilizing linked-tracking heliostats is analyzed for distributed-scale concentrated solar power. Smaller linkage groupings are typically found to have a… (more)

Dunham, Marc Tyler Deo

2012-01-01

297

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.

298

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

299

Characterization of underground cable incipient failures from on-line monitoring of underground distribution power systems  

E-print Network

Electric's underground power distribution systems; b. controlled experiments on field aged cable samples and on new intentionally damaged distribution cable sections at the TAMU Downed Conductor Test Facility. 2. Analysis of data recorded at TAMU and TU...

Cardoso, Jesus

2012-06-07

300

A study of electric power quality using storage system in distributed generation  

Microsoft Academic Search

This paper describes a method to improve the power quality of a distributed generation (DG) power system. The proposed method uses a power storage system with DG. Here, DG is assumed the renewable energy systems such as photovoltaic generation (PV), wind power generation (WG) and fuel cells (FC), etc. The effect to use the storage battery is shown by the

K. Yukita; Y. Goto; K. Ichiyanagi; K. Hirose

2007-01-01

301

Voltage and Frequency Stability of Weak Power Distribution Networks with Droop-Controlled  

E-print Network

Voltage and Frequency Stability of Weak Power Distribution Networks with Droop to improve power quality and reliability of power grids. These DG's, however, may cause voltage and frequency with rated power level (stressful). Weak networks complicate voltage stability and frequency synchronization

Lemmon, Michael

302

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

303

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

304

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

305

Proposal for Wireless Power Distribution System with Capacitive Coupling Using One-Pulse Switching Active Capacitor  

NASA Astrophysics Data System (ADS)

Wireless electric power distribution is an attractive means of supplying power to mobile equipment such as mobile phones and electric vehicles. Magnetic field coupling is the most popular method for wireless power distribution. However, this method has certain disadvantages such as power decrease in the case of inexact placement of couplings. Wireless power distribution with capacitive coupling has been proposed to overcome the disadvantages of wireless power distribution with magnetic field coupling. It is, however, difficult to transfer high power owing to the small capacitance of capacitive coupling. The authors propose a new power converter suitable for wireless power distribution with capacitive coupling using a novel one-pulse switching active capacitor (OPSAC) to enhance power transfer. The proposed system improves the power transfer efficiency without LC resonance and is hence robust to parameter change. In this paper, a wireless power distribution system with improved OPSAC (I-OPSAC) is proposed. In the I-OPSAC, the dc voltage source for the inverter is replaced by a capacitor because the OPSAC behaves like a reactive element. The I-OPSAC shows stable operation without any feedback loop including dc capacitor voltage control. In this paper, a control scheme and the detailed operational characteristics are reported, in addition to the simulations and experimental results.

Funato, Hirohito; Chiku, Yuki; Harakawa, Ken-Ichi

306

Numerical Electric Field Analysis of Power Status Sensor Observing Power Distribution System Taking into Account Voltage Divider Measurement Circuit  

NASA Astrophysics Data System (ADS)

We have proposed and preproducted the voltage-current waveform sensor of resin molded type for measuring the power factor and harmonics in power distribution systems. We have executed numerical electromagnetic analyses using the finite element method to estimate the characteristics and behaviours of the sensor. Although the magnetic field analyses for the current sensor have involved the measurement circuit, the electric field analyses have not included the measurement circuit for measuring voltage waveforms of power lines. In this paper, we describe the electric field analyses with the measurement circuit and prove the insulating strength of the proposed sensor permissible to the use in 22kV power distribution systems.

Kubo, Takuro; Furukawa, Tatsuya; Itoh, Hideaki; Fukumoto, Hisao; Wakuya, Hiroshi; Ohchi, Masashi

307

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

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

308

Optimal distributed power generation under network load constraints  

E-print Network

, mainly because of the development of novel components for decentral power generation (solar panels, small wind turbines and heat pumps). This gives rise to the question how many units of each type (solar panel (DPG) refers to an electric power source such as solar, wind or combined heat power (CHP) connected

Utrecht, Universiteit

309

OPTIMAL DISTRIBUTED POWER GENERATION UNDER NETWORK LOAD CONSTRAINTS,  

E-print Network

of novel components for decentral power generation (solar panels, small wind turbines and heat pumps). This gives rise to the question how many units of each type (solar panel, small wind turbine or central-producers. Decentralized Power Generation (DPG) refers to an electric power source such as solar, wind or combined heat

Frank, Jason

310

Abstract--Many studies comparing AC and DC systems have focused on efficiency, stability, and controllability, but have not  

E-print Network

system has a separate distribution system providing protection to the overall ship power systems when be achieved by moving to a DC system with three lines. Index Terms-DC power systems, power system modeling. These alternative energies are prevailingly DC. However, the power infrastructure is presently based on an AC system

Tolbert, Leon M.

311

Power distribution in complex environmental negotiations: Does balance matter?  

USGS Publications Warehouse

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

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

1997-01-01

312

Analysis of volume distribution of power loss in ferrite cores  

NASA Astrophysics Data System (ADS)

We present a technique to estimate the inhomogeneities of magnetic loss across the section of ferrite cores under ac excitation. The technique is based on two distinct calorimetric methods that we presented elsewhere. Both methods are based on the measurement of the rate of increase of the sample temperature under adiabatic condition. The temperature ramp is recorded either measuring the sample bulk resistivity or using a platinum probe pasted on the sample surface. As an example we apply the procedure to an industrial sample of Mn-Zn ferrite under controlled sinusoidal excitation with a peak induction of 50 mT in the range between 100 kHz and 2 MHz. The results are discussed by comparison with simulations of the dissipation field profile through the sample, calculated using a finite element method (FEM) code.

LoBue, M.; Loyau, V.; Mazaleyrat, F.

2011-04-01

313

An Evaluation of Power-Proportional Data Placement for Hadoop Distributed File Systems  

Microsoft Academic Search

Power-saving storage in data centers is now gaining much interest because of the increase in power requirements. In particular, with the expansion of services requiring distributed-processing frameworks, power proportionality in power-aware file systems is attracting great attention from academia and industry. The concept of power proportionality is that a system should perform work in proportion to the energy it consumes.

Hieu Hanh Le; Satoshi Hikida; Haruo Yokota

2011-01-01

314

Power components for the Space Station 20-kHz power distribution system  

NASA Technical Reports Server (NTRS)

Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of the Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed.

Renz, David D.

1988-01-01

315

Power components for the space station 20-kHz power distribution system  

NASA Technical Reports Server (NTRS)

Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of The Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed.

Renz, David D.

1988-01-01

316

Analysis and design of electronic transformers for electric power distribution system  

Microsoft Academic Search

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

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

1999-01-01

317

Design of a solid state fault isolation device for implementation in power electronics based distribution systems  

Microsoft Academic Search

This paper addresses the timely issues of modeling of, and defining selection criteria for, a solid state fault isolation device (SSFID) to be used in power electronic based distribution systems. The paper derives the SSFID parameters by mapping the characteristics of a conventional medium-voltage distribution system onto that of the power electronic based Future Renewable Electric Energy Delivery and Management

O. Vodyakho; M. Steurer; C. Edrington; G. Karady; B. Chowdhury; S. Bhattacharya

2009-01-01

318

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

Microsoft Academic Search

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

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

1995-01-01

319

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

Microsoft Academic Search

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

A. Panosyan; B. R. Oswald

2004-01-01

320

Assessment of distributed photovoltair electric-power systems  

NASA Astrophysics Data System (ADS)

The development of a methodology to assess the potential impacts of distributed photovoltaic (PV) systems on electric utility systems, including subtransmission and distribution networks, and to apply that methodology to several illustrative examples was developed. The investigations focused upon five specific utilities. Impacts upon utility system operations and generation mix were assessed using accepted utility planning methods in combination with models that simulate PV system performance and life cycle economics. Impacts on the utility subtransmission and distribution systems were also investigated. The economic potential of distributed PV systems was investigated for ownership by the utility as well as by the individual utility customer.

Neal, R. W.; Deduck, P. F.; Marshall, R. N.

1982-10-01

321

Analysis and design of electronic transformer for electric power distribution and utility interface of power electronic systems  

Microsoft Academic Search

In electric power distribution and power electronics applications, a transformer is an indispensable component and performs many functions. However, at low frequencies, it is one of the most bulky and expensive components. In this dissertation, the concept of electronic transformer is proposed which results in a considerable reduction in the size and weight of the transformer. 4-quadrant converters are employed

Moonshik Kang

2000-01-01

322

Issues of thermal testing of AC LEDs  

Microsoft Academic Search

In this paper we aim at highlighting different aspects of thermal testing of AC LEDs, especially of retrofit LED lamps which are directly driven from the AC mains supply. The main focus is the concept of thermal impedance applied for AC driven LEDs and the AC heating power. The paper gives an overview of the different representations of the thermal

Andras Poppe; Bernie Siegal; Gabor Farkas

2011-01-01

323

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

324

Centralized and Distributed Generated Power Systems -A Comparison Approach  

E-print Network

White Paper Power Systems Engineering Research Center Empowering Minds to Engineer the Future Electric information about this white paper, contact: James A. Momoh Professor of Electrical & Computer Engineering Research Center The Power Systems Engineering Research Center (PSERC) is a multi-university Center

325

Multi-agent based Distributed Reactive Power Control Method  

NASA Astrophysics Data System (ADS)

In order to maintain system voltage within the optimal range and prevent voltage instability phenomena before they occur, a variety of phase modifying equipment is installed in optimal locations throughout the power system network and a variety of methods of voltage reactive control are employed. In this paper, the voltage reactive control problem is considered as the two sub problems such as voltage control and reactive power control. The proposed multi-agent system intends to resolve the reactive power control sub problem. In this system, three types of agents are installed in substations in order to maintain the primary bus voltage within the operation limit by allocating the reactive power. In order to verify the performance of the proposed method, it has been applied to the model network system. The simulation results show that the proposed method is a promising approach to keep the primary bus voltage within the operational limit by changing the reactive power allocation.

Nagata, Takeshi; Kunisa, Daisuke; Saiki, Hiroshi; Hatano, Ryousuke

326

Equivalent circuits for power system studies on the A-C network calculator  

E-print Network

~ ~ ~ 1 I. Fundamental Features of the Network Calculator . . . 3 II ' Load Representation 12 III. Transmission Line Networks ~ ~ ~ ~ ~ ~ ~ 14 IV. Synchronous Machines and Static Capacitors . . . . , 25 V. Transformer Equivalent Circuits 36 VI... are employed to illustrate the methods used to convert power system elements to the circuit elements and networks which represent them on the Network Calculator. The characteristics and constants of all transmission lines, transformers, and synchronous...

Kolb, Walter Jean

2012-06-07

327

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

328

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

Microsoft Academic Search

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

Todd Mander; Farhad Nabhani; Lin Wang; Richard Cheung

2007-01-01

329

Design Concepts for Power Distribution Equipment Serving Non-Linear Loads  

E-print Network

, transformers, and power capacitors. SYMMETRICAL COMPONENT ANALYSIS The phase currents on a balanced, three-phase, four-wire, grounded-neutral distribution system, separated by 120? and equal in magnitude, add vectorially and cancel in the grounded... conductor overload, high neutral-to-ground voltage drop, and circulating current in the delta primary winding of delta-wye connected distribution transformers. Symmetrical Components and Non-Linear Loads A balanced load on a power distribution system...

Massey, G. W.

330

Fokker–Planck equation of distributions of financial returns and power laws  

Microsoft Academic Search

Our purpose is to relate the Fokker–Planck formalism proposed by [Friedrich et al., Phys. Rev. Lett. 84 (2000) 5224] for the distribution of stock market returns to the empirically well-established power-law distribution with an exponent in the range 3–5. We show how to use Friedrich et al.'s formalism to predict that the distribution of returns is indeed asymptotically a power

Didier Sornette

2001-01-01

331

Z-Source-Inverter-Based Flexible Distributed Generation System Solution for Grid Power Quality Improvement  

Microsoft Academic Search

Distributed generation (DG) systems are usually connected to the grid using power electronic converters. Power delivered from such DG sources depends on factors like energy availability and load demand. The converters used in power conversion do not operate with their full capacity all the time. The unused or remaining capacity of the converters could be used to provide some ancillary

Chandana Jayampathi Gajanayake; D. Mahinda Vilathgamuwa; Poh Chiang Loh; Remus Teodorescu; Frede Blaabjerg

2009-01-01

332

Distributed PI-Control with Applications to Power Systems Frequency Control  

E-print Network

Distributed PI-Control with Applications to Power Systems Frequency Control Martin Andreasson12 to frequency control of power transmission systems. Sufficient stability criteria are derived, and it is shown, decentralized PI-control is known to destabilize the system, as is the case for power transmission systems [3

Dimarogonas, Dimos

333

Power cable fault management with fiber optic distributed sensors: future technological trends  

Microsoft Academic Search

This paper presents an analysis of fiber distributed sensors applied to power cable fault management, and proposes a more suitable solution for the future. In tomorrow's fast-paced deregulated environment, exploiting new technologies for competitive advantage has become a major incentive in the power business delivery. In power lines, the main parameters that need real time checking are temperature, partial discharges,

Stephane R. Teral; Marcos Kleinerman; Patrice Malavielle

1998-01-01

334

A Tri-directional power electronic transformer for photo voltaic based distributed generation application  

Microsoft Academic Search

Expanding the size and demand of the electrical network, make the use of distributed generation inevitable especially, when the produced power can be expected as a green power. Furthermore, this growth in size brings up the importance of volume and weight of instruments, used in. Power electronic transformer is an attempt to reduce the weight and occupied space of the

S. H. Hosseini; M. B. B. Sharifian; M. Sabahi; Z. Hooshi; G. B. Gharehpetian

2009-01-01

335

Reactive Protocols for Aircraft Electric Power Distribution Huan Xu, Ufuk Topcu, and Richard M. Murray  

E-print Network

Reactive Protocols for Aircraft Electric Power Distribution Huan Xu, Ufuk Topcu, and Richard M. Murray Abstract-- The increasing complexity of electric power sys- tems leads to integration power system that meets these system requirements and reacts dynamically to changes in internal system

Murray, Richard M.

336

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

337

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

338

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

339

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

340

Distributed Abstract State Machines and Their Expressive Power  

E-print Network

benefits for the specification and analysis of real-world systems [4, 3]. Gurevich introduced in [7 Introduction Abstract State Machines have been introduced as a "computation model that is more powerful

Freytag, Johann-Christoph

341

Distributed power control in ad-hoc wireless networks  

Microsoft Academic Search

Mobile ad-hoc networking involves peer-to-peer communication in a network with a dynamically changing topology. Achieving energy efficient communication in such a network is more challenging than in cellular networks since there is no centralized arbiter such as a base station that can administer power management. We propose and evaluate a power control loop, similar to those commonly found in cellular

Sharad Agarwal; Randy H. Katz; Srikanth V. Krishnamurthy; Son K. Dao

2001-01-01

342

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

343

Fuzzy logic based operated device identification in power distribution systems  

E-print Network

Fault location in distribution systems is a challenging task because of the lack of homogeneity in the system and due to uncertainity in the data used for estimating the faulted sections. Fuzzy logic has widely been applied for handling...

Manivannan, Karthick Muthu

2012-06-07

344

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

345

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

2014-11-01

346

Superconductive AC current limiter  

Microsoft Academic Search

This patent describes an AC current limiter for a power transport line including a power supply circuit and feeding a load circuit via an overload circuit-breaker member. The limiter comprises a transformer having a primary winding connected in series between the power supply circuit and the load circuit and at least one secondary winding of superconductor material contained in a

Bekhaled

1987-01-01

347

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

348

Reliability Improvement Programs in Steam Distribution and Power Generation Systems  

E-print Network

savings, are steam trap, valve and condensate return systems. Such systems can be found in power generation, steam distri bution, and in all types of durable and non-durable in dustrial production. Figure 1 explains that the costs to maintain steam... savings, are steam trap, valve and condensate return systems. Such systems can be found in power generation, steam distri bution, and in all types of durable and non-durable in dustrial production. Figure 1 explains that the costs to maintain steam...

Atlas, R. D.

349

The probability distribution of wind power from a dispersed array of wind turbine generators  

NASA Astrophysics Data System (ADS)

A method is presented for estimating the probability distribution of wind power from a dispersed array of wind turbine sites where the correlation between wind speeds at distinct sites is less than unity. The distribution is obtained from a model for the joint probability distribution of wind speeds. This is able to incorporate arbitrary inter-site correlations. It is shown that this joint distribution reduces in the single site case to a wind speed distribution closely approximating the widely used Weibull; the multiple site power distribution is also shown to fit adequately to data on wind speeds from four sites in Western Australia. Results presented in graphical and tabular form for a range of representative cases show that a significant reduction in the variability of total wind power output may result from dispersion of aerogenerator sites; a quantitative guide to the magnitude of these effects is also provided.

Carlin, J.; Haslett, J.

1982-03-01

350

Modeling the Effect of Hurricanes on Power Distribution Systems  

E-print Network

: : : : : : : : : : : : : : : : : 9 III Conductor sizing in Micropolis : : : : : : : : : : : : : : : : : : : : : 24 IV Sequence impedance and capacitance values for three phase single circuit overhead lines : : : : : : : : : : : : : : : : : : : : : : : : : : : 28 V Resistance... : : : : : : : : 19 8 Fragility curve showing number of industries losing power for a given wind speed in the absence of routing : : : : : : : : : : : : : : : 20 9 Three phase single circuit overhead line conductor con guration : : : 25 10 Single phase overhead...

Chanda, Suraj

2012-10-19

351

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

352

Microgrids, virtual power plants and our distributed energy future  

SciTech Connect

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

Asmus, Peter

2010-12-15

353

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

354

Distributed Leadership: The Uses and Abuses of Power  

ERIC Educational Resources Information Center

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

Lumby, Jacky

2013-01-01

355

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

Microsoft Academic Search

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

Kaushik Basu; N. Mohan

2010-01-01

356

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

SciTech Connect

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

Choi, Woo-Young; Lai, Jih-Sheng (Jason) [Future Energy Electronics Center, Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States)

2010-04-15

357

A compact DC-to-DC power converter for distributed power processing  

SciTech Connect

This paper presents a compact (55 W/in[sup 3]), efficient (86% power train), 1 MHz switch-mode, dc-to-dc power converter contained in a 2 in by 2 in by 0.25 in, 1 in[sup 3] package. It also describes the interleaved forward topology, steady-state analysis, switch transitions, capacitor substrate, planar printed-wiring-board transformer, packaging, electrical performance, power loss analysis, thermal analysis, reliability, and efficiency and power density improvements.

Lo, D.S.; Mulkern, J.H.; Henze, C.P. (Paramax Systems Corp., A Unisys Co., St. Paul, MN (United States))

1992-10-01

358

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

359

Voltage multi-stability in distribution grids with power flow reversal  

E-print Network

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

Hung D. Nguyen; Konstantin Turitsyn

2014-04-25

360

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 ...

361

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

362

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

363

DCM Boost interleaved converter for operation in AC and DC to trolleybus application  

Microsoft Academic Search

This paper is based on the development and experimental analysis of a DCM Boost interleaved converter suitable for application in traction systems of electrical vehicles pulled by electrical motors (Trolleybus), which are powered by urban DC or AC distribution networks. This front-end structure is capable of providing significant improvements in trolleybuses systems and in the urban distribution network costs, and

Carlos A. Canesin; Flávio A. S. Gonçalves; Guilherme A. Melo; Luiz C. G. de Freitas

2009-01-01

364

Impact of V2G on Distribution Feeder: A Power Loss Reduction Approach  

NASA Astrophysics Data System (ADS)

The penetration of Vehicle-to-Grid (V2G) into the electrical distribution system has potential to create room for many operational benefits. A V2G facility installed on a distribution feeder line segment may affect power loss in the distribution system. Mathematical models are developed to study how magnitude of V2G reactive power injection and different mixes of uniformly distributed loads and lumped loads can impact power loss on a distribution system feeder. The V2G facilities assumed in this research are V2G parking lots with provision for injecting reactive currents into the feeder of a distribution network. It is shown that loss reduction can be greatly influenced by the pattern of loading, the amount of V2G reactive injection as well as position and number of V2G parking lot along the feeder segment. Useful results are obtained, with a promise that more than 95% power loss reduction (relative to power loss in the system without V2G installed) is possible by optimally locating a V2G parking lot along the feeder. It is observed that location and capacity injection of a V2G facility are the most critical for loss reduction. It was concluded that proper system planning and operational practice are required in order to reduce power losses.

Chukwu, Uwakwe C.; Mahajan, Satish M.

2013-08-01

365

Distributed clock gating for power reduction of a programmable waveform generator for neural stimulation.  

PubMed

This paper describes how to employ distributed clock gating to achieve an overall low power design of a programmable waveform generator intended for a neural stimulator. The power efficiency is enabled using global timing control combined with local amplitude distribution over a bus to the local stimulator frontends. This allows the combination of local and global clock gating for complete sub-blocks of the design. A counter and a shifter employed at the local digital stimulator reduce the design complexity for the waveform generation and thus the overall power consumptions. The average power results indicate that 63% power can be saved for the global stimulator control unit and 89-96% power can be saved for the local digital stimulator by using the proposed approach. The circuit has been implemented and successfully tested in a 0.35 µm AMS HVCMOS technology. PMID:23366775

Noorsal, Emilia; Sooksood, Kriangkrai; Bihr, Ulrich; Becker, Joachim; Ortmanns, Maurits

2012-01-01

366

Multiobjective allocation of remotely controlled switches in an electric distribution power system  

Microsoft Academic Search

Because of the growing necessity of decreasing restoration time of electric power services after a failure, it becomes extremely relevant to look for new optimization techniques. This work proposes a new method to solve the remotely controlled switches devices allocating problem in an electric power distribution system. An Evolutionary Multiobjective Algorithm inspired the proposed technique. The Strength Pareto Evolutionary Algorithm

A. Villasanti; B. Baran; P. Gardel

2008-01-01

367

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

368

Robotics applied to work conditions improvement in power distribution lines maintenance  

Microsoft Academic Search

Based on the analysis of the tasks concerning maintenance of power distribution networks from the Ergonomics point of view, Paulista Power & Light Company (CPFL, Brazil) and the University of Sao Paulo (USP, Brazil) started a project focused on the application of Mechatronics and Robotics techniques and knowledge to improve the maintenance activity, also establishing a roadmap of developments to

R. A. Roncolatto; N. W. Romanelli; A. Hirakawa; O. Horikawa; D. M. Vieira; R. Yamamoto; V. C. Finotto; V. Sverzuti; I. P. Lopes

2010-01-01

369

Distributed Learning Strategies for Collaborative Agents in Adaptive Decen-tralized Power Systems  

E-print Network

Distributed Learning Strategies for Collaborative Agents in Adaptive Decen- tralized Power Systems is obsolete, due to the wide dispersion and high unpredictability of wind and solar based power facilities. In this paper the main contribution is to make the negotiation strategies themselves adaptive across periods. We

Wedde, Horst F.

370

Distributed Energy Resources and Control: A power system point of view  

E-print Network

Distributed Energy Resources and Control: A power system point of view Oliver Gehrke, Stephanie Ropenus, Philippe Venne Abstract The power grid is currently facing tremendous changes in the way the energy is produced, transmitted and consumed. The increasing number of actors and the demand for more

371

Assessment of the Impact of SFCL on Voltage Sags in Power Distribution System  

Microsoft Academic Search

This paper assesses and analyses the effects of super- conducting fault current limiter (SFCL) installed in power dis- tribution system on voltage sags. First of all, resistor-type SFCL is modeled using PSCAD\\/EMTDC to represent the quench and recovery characteristics based on the experimental results. Next, typical power distribution system of Korea is modeled. When the SFCLisinstalledinvariouslocationsfromthestartingpointtoend point of feeders, improvement

Jong-Fil Moon; Sung-Hun Lim; Jae-Chul Kim; Sang-Yun Yun

2011-01-01

372

Electrical Power Transmission and Distribution Safety. Module SH-40. Safety and Health.  

ERIC Educational Resources Information Center

This student module on electrical power transmission and distribution safety is one of 50 modules concerned with job safety and health. This module focuses on some of the general safety rules, techniques, and procedures that are essential in establishing a safe environment for the electrical power transmission worker. Following the introduction,…

Center for Occupational Research and Development, Inc., Waco, TX.

373

Power quality improvement based on novel power electronic transformer  

Microsoft Academic Search

This paper presents a novel topology of power electronic transformer. In the design process, the AC\\/DC, DC\\/AC, AC\\/AC converters and high frequency transformer have been used. One matrix converter operates as AC\\/AC converter in power electronic transformer. The proposed power electronic transformer performs typical functions and has advantages such as power factor correction, voltage sag and swell elimination, voltage flicker

M. R. Banaei; E. Salary

2011-01-01

374

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...

375

Improvement of Power Quality and Reliability with multifunctional PV-inverters in distributed energy systems  

Microsoft Academic Search

The share of distributed generation (DG) within the distribution network increases strongly. A lot of these DG units are driven by renewable energy sources (RES). Up to now, these units only inject active power depending from the availability of their primary source. In future on the one hand DG units have to contribute to grid stability, but on the other

D. Geibel; T. Degner; C. Hardt; M. Antchev; A. Krusteva

2009-01-01

376

On-line Power Savings in a Distributed Multi-stage Router Architecture  

E-print Network

On-line Power Savings in a Distributed Multi-stage Router Architecture Andrea Bianco, Fikru on a distributed multi-stage software router (MSSR) architecture internally composed by several per- sonal computers (PCs) to overcome scalability and performance issues of software routers (SRs) based on a single

377

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

378

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

Microsoft Academic Search

The design of a three-level distributed control system for fire detection and monitoring in a nuclear power plant is presented. The system design fully satisfies the requirements of the US NRC Regulatory Guides and the provisions of the latest National Fire Codes. The three levels of distributed control are: (1) Local Fire Detection Control Panel, (2) Main Control Room Fire

C. N. Bagchi; A. K. Chakraberti

1984-01-01

379

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

E-print Network

, are placing new challenges to the power grid. Now the grid is more constrained and it is expected to perform. Those variations on generation, if not properly accounted for, may bring different challenges, including and their location. Choi [3] shows that inclusion of distributed generation in a distribution system would reduce

Catholic University of Chile (Universidad Católica de Chile)

380

Learning Price-Elasticity of Smart Consumers in Power Distribution Systems  

E-print Network

Learning Price-Elasticity of Smart Consumers in Power Distribution Systems Vicenc¸ G´omez1, Michael comprised of many small individual consumers on distribution grids. However, to utilize these re- sources rely on consumers and/or loads responding to exogenous signals, typically in the form of energy pricing

Gómez, Vicenç

381

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 a resonant circuit and one or more repeater, or relay, resonant tanks that couple energy from source coil of sensor and wireless networks. I. INTRODUCTION Distributed wireless systems are extremely useful in many

Cervesato, Iliano

382

Industry sector analysis: Electric power distribution and transmission equipment, Brazil, October 1993. Export trade information  

SciTech Connect

The report is an assessment of the Brazilian market for electric power distribution and transmission equipment principally comprising the following equipment: Transformers; Automatic circuit breakers; Lightning arresters; Electrical switching and circuit protection apprts; Electrical panel and distribution boards; and Electrical insulators.

Cunha, R.

1994-01-01

383

A high-density modular power processor for distributed military power systems  

Microsoft Academic Search

A high-density power processor in a SEM (standard electronic module) Format-E package is described. The power converter features a full-bridge PWM (pulse-width modulated) topology that uses transition resonance to achieve zero-voltage switching. The switching sequence of the phase-shifted topology simplifies the MOSFET drive circuitry. The converter's tolerance to low magnetizing inductance reduces the volume required for the power transformer. A

M. M. Walters; W. M. Polivka

1989-01-01

384

Evaluation of 400V DC distribution in telco and data centers to improve energy efficiency  

Microsoft Academic Search

In a typical data center, less than half the energy consumed is delivered to the compute load, with the rest lost in power conversion, distribution and cooling. Traditionally power distribution is at 400\\/480 V AC in data centers and at -48 V DC in telco facilities. Higher voltage DC has been proposed as an energy efficient distribution option for both

Annabelle Pratt; Pavan Kumar; Tomm V. Aldridge

2007-01-01

385

The ion energy distributions and ion flux composition from a high power impulse magnetron sputtering discharge  

Microsoft Academic Search

The energy distribution of sputtered and ionized metal atoms as well as ions from the sputtering gas is reported for a high power impulse magnetron sputtering (HIPIMS) discharge. High power pulses were applied to a conventional planar circular magnetron Ti target. The peak power on the target surface was 1–2 kW\\/cm2 with a duty factor of about 0.5%. Time resolved, and

J. Bohlmark; M. Lattemann; J. T. Gudmundsson; A. P. Ehiasarian; Y. Aranda Gonzalvo; N. Brenning; U. Helmersson

2006-01-01

386

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

387

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

388

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

389

Monitoring and optimization of power transmission and distribution systems  

NASA Astrophysics Data System (ADS)

We investigate the state estimation application and present details of the modified implementation to account for two types of power flow controllers. Issues of observability, robustness against bad data, initialization and convergence characteristics are discussed within this dissertation. We present a tracking state estimator for systems operating under non-sinusoidal but periodic steady state conditions. The proposed estimator is designed to be computationally efficient by transforming the measurement equations in a special manner so that the sparsity of the corresponding discrete time matrix equations is significantly enhanced. Zero injection constraints are also included to take advantage of the increased redundancy. We present an algebraic method that uses the triangular factors of singular, symmetric gain matrix to determine the observable islands of a measured power system. This is accomplished in a non-iterative manner via the use of selected rows of the inverse factors. Implementation of the proposed method presents little additional effort, since sparse triangular factorization and forward/back substitution procedures common to existing state estimators, are the only required functions. A multiple measurement placement algorithm is developed based on the observability analysis algorithms described above. This algorithm has the ability to update the measurement set of an unobservable system by placing multiple measurements in a non-iterative manner. This is an improvement over the conventional approach where measurements are added one at a time until full observability is attained. The newly proposed observability analysis algorithms are also extended to the Hachtel's formulation of state estimation. This extension facilitates the use and integration of developed techniques in commonly used programs by industry. This study accounts for the voltage harmonic distortion brought about by the placement of capacitors. The optimal capacitor placement problem is formulated as a mixed integer nonlinear programming problem which determines the location, type and size of the shunt capacitors to minimize the harmonic levels, losses and the capacitance costs. A heuristic method is used to obtain a near optimal solution for realistic size systems.

Gou, Bei

2000-10-01

390

Simplified mantle architecture and distribution of radiogenic power  

NASA Astrophysics Data System (ADS)

The mantle components that represent the source region of ocean island basalts (OIB) and feed hotspot volcanism are predicted to contain 160 ± 20 (2?m) ng/g Th, a heat-producing element. This critical model composition indicates that the OIB source region (OSR) comprises a significant amount of recycled oceanic crust and constitutes 19+3-2 (2?m)% of the mantle by mass. The mass fraction of this reservoir supports a mantle architecture with a basal thermochemical layering at an average depth of 2000 ± 100 (2?m) km or two thermochemical piles that extend up to midmantle levels. The hotspot source described here generates 10 pW/kg of radiogenic heat and supplies 7.3 TW to the planet's total surface heat flux. Given that the silicate portion of the Earth produces some 20.4 TW of radiogenic power, with 7.2 TW derived from the continental crust, the mantle source responsible for mid-ocean ridge volcanism provides only 5.9 TW of radiogenic power (or <2 pW/kg). As a result, the source of hotspots generates >5x more radiogenic heat than the source of mid-ocean ridges, thus contributing to the energetics that drive mantle convection and potentially the formation of long-lived plumes via bottom heating of the modern mantle. The potential for a sequestered or unsampled mantle reservoir would impact the relative mass fractions of the source regions of OIB and mid-ocean ridge volcanism but not the compositional model of the OSR presented here.

Arevalo, Ricardo; McDonough, William F.; Stracke, Andreas; Willbold, Matthias; Ireland, Thomas J.; Walker, Richard J.

2013-07-01

391

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

392

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

393

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

394

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

395

Design Considerations for Series-Connected Distributed FACTS Converters  

Microsoft Academic Search

The power grid is aging, and getting increasingly congested. Conventional solutions, such as flexible ac transmission systems (FACTS) can be used to control power flow on the grid. However, widespread adoption of this technology has been hampered by high costs and reliability concerns. The concept of distributed FACTS devices, as an alternative approach to realizing cost-effective power flow control, has

Harjeet Johal; Deepak Divan

2007-01-01

396

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

397

Power distribution in the snowflake divertor in TCV  

NASA Astrophysics Data System (ADS)

TCV experiments demonstrate the basic power exhaust properties of the snowflake (SF) plus and SF minus divertor configurations by measuring the heat fluxes at each of their four divertor legs. The measurements indicate an enhanced transport into the private flux region and a reduction of peak heat fluxes compared to a similar single null configuration. There are indications that this enhanced transport cannot be explained by the modified field line geometry alone and likely requires an additional or enhanced cross-field transport channel. The measurements, however, do not show a broadening of the scrape-off layer (SOL) and, hence, no increased cross-field transport in the common flux region. The observations are consistent with the spatial limitation of several characteristic SF properties, such as a low poloidal magnetic field in the divertor region and a long connection length to the inner part of the SOL closest to the separatrix. Although this limitation is typical in a medium sized tokamak like TCV, it does not apply to significantly larger devices where the SF properties are enhanced across the entire expected extent of the SOL.

Reimerdes, H.; Canal, G. P.; Duval, B. P.; Labit, B.; Lunt, T.; Vijvers, W. A. J.; Coda, S.; De Temmerman, G.; Morgan, T. W.; Nespoli, F.; Tal, B.; the TCV Team

2013-12-01

398

Finite-Element Model Predicts Current Density Distribution for Clinical Applications of tDCS and tACS  

PubMed Central

Transcranial direct current stimulation (tDCS) has been applied in numerous scientific studies over the past decade. However, the possibility to apply tDCS in therapy of neuropsychiatric disorders is still debated. While transcranial magnetic stimulation (TMS) has been approved for treatment of major depression in the United States by the Food and Drug Administration (FDA), tDCS is not as widely accepted. One of the criticisms against tDCS is the lack of spatial specificity. Focality is limited by the electrode size (35?cm2 are commonly used) and the bipolar arrangement. However, a current flow through the head directly from anode to cathode is an outdated view. Finite-element (FE) models have recently been used to predict the exact current flow during tDCS. These simulations have demonstrated that the current flow depends on tissue shape and conductivity. To face the challenge to predict the location, magnitude, and direction of the current flow induced by tDCS and transcranial alternating current stimulation (tACS), we used a refined realistic FE modeling approach. With respect to the literature on clinical tDCS and tACS, we analyzed two common setups for the location of the stimulation electrodes which target the frontal lobe and the occipital lobe, respectively. We compared lateral and medial electrode configuration with regard to their usability. We were able to demonstrate that the lateral configurations yielded more focused stimulation areas as well as higher current intensities in the target areas. The high resolution of our simulation allows one to combine the modeled current flow with the knowledge of neuronal orientation to predict the consequences of tDCS and tACS. Our results not only offer a basis for a deeper understanding of the stimulation sites currently in use for clinical applications but also offer a better interpretation of observed effects. PMID:23015792

Neuling, Toralf; Wagner, Sven; Wolters, Carsten H.; Zaehle, Tino; Herrmann, Christoph S.

2012-01-01

399

Comparison of AC losses, magnetic field/current distributions and critical currents of superconducting circular pancake coils and infinitely long stacks using coated conductors  

NASA Astrophysics Data System (ADS)

A model is presented for calculating the AC losses, magnetic field/current density distribution and critical currents of a circular superconducting pancake coil. The assumption is that the magnetic flux lines will lie parallel to the wide faces of tapes in the unpenetrated area of the coil. Instead of using an infinitely long stack to approximate the circular coil, this paper gives an exact circular coil model using elliptic integrals. A new efficient numerical method is introduced to yield more accurate and fast computation. The computation results are in good agreement with the assumptions. For a small value of the coil radius, there is an asymmetry along the coil radius direction. As the coil radius increases, this asymmetry will gradually decrease, and the AC losses and penetration depth will increase, but the critical current will decrease. We find that if the internal radius is equal to the winding thickness, the infinitely long stack approximation overestimates the loss by 10% and even if the internal radius is reduced to zero, the error is still only 60%. The infinitely long stack approximation is therefore adequate for most practical purposes. In addition, the comparison result shows that the infinitely long stack approximation saves computation time significantly.

Yuan, Weijia; Campbell, A. M.; Hong, Z.; Ainslie, M. D.; Coombs, T. A.

2010-08-01

400

Recognizing animal-caused faults in power distribution systems using artificial neural networks  

SciTech Connect

Faults are likely to occur in most power distribution systems. If the causes of the faults are known, specific action can be taken to eliminate the fault sources as soon as possible to avoid unnecessary costs, such as power system down-time cost, that are caused by failing to identify the fault sources. However, experts that can accurately recognize the causes of distribution faults are scarce and the knowledge about the nature of these faults is easily transferable from person to person. Therefore, artificial neural networks are used in this paper to recognize the causes of faults in power distribution systems, based on fault currents information collected for each outage. Actual field data collected by Duke Power Company are used in this paper. The methodology and implementation of artificial neural networks and fuzzy logic for the identification of animal-caused distribution faults will be presented. Satisfactory results have been obtained, and the developed methodology can be easily generalized and used to identify other causes of faults in power distribution systems.

Chow, Mo Yuen; Yee, S.O. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Electrical and Computer Engineering); Taylor, L.S. (Duke Power Co., Charlotte, NC (United States). Distribution Engineering)

1993-07-01

401

Performance testing of a high frequency link converter for Space Station power distribution system  

NASA Technical Reports Server (NTRS)

The testing of a brassboard version of a 20-kHz high-frequency ac voltage link prototype converter dynamics for Space Station application is presented. The converter is based on a three-phase six-pulse bridge concept. The testing includes details of the operation of the converter when it is driving an induction machine source/load. By adapting a field orientation controller (FOC) to the converter, four-quadrant operation of the induction machine from the converter has been achieved. Circuit modifications carried out to improve the performance of the converter are described. The performance of two 400-Hz induction machines powered by the converter with simple V/f regulation mode is reported. The testing and performance results for the converter utilizing the FOC, which provides the capability for rapid torque changes, speed reversal, and four-quadrant operation, are reported.

Sul, S. K.; Alan, I.; Lipo, T. A.

1989-01-01

402

Power for Genetic Association Studies with Random Allele Frequencies and Genotype Distributions  

PubMed Central

One of the first and most important steps in planning a genetic association study is the accurate estimation of the statistical power under a proposed study design and sample size. In association studies for candidate genes or in fine-mapping applications, allele and genotype frequencies are often assumed to be known when, in fact, they are unknown (i.e., random variables from some distribution). For example, if we consider a diallelic marker with allele frequencies of 0.5 and 0.5 and Hardy-Weinberg proportions, the three genotype frequencies are often assumed to be 0.25, 0.50, and 0.25, and the statistical power is calculated. Unfortunately, ignoring this source of variation can inflate the estimated power of the study. In the present article, we propose averaging the estimates of power over the distribution of the genotype frequencies to calculate the true estimate of power for a fixed allele frequency. For the usual situation, in which allele frequencies in a population are not known, we propose placing a prior distribution on the allele frequency, taking advantage of any available genotype information. This Bayesian approach provides a more accurate estimate of power. We present examples for quantitative and qualitative traits in cohort studies of unrelated individuals and results from an extensive series of examples that show that ignoring the uncertainty in allele frequencies can inflate the estimated power of the study. We also present the results from case-control studies and show that standard methods may also overestimate power. As discussed in this article, the approach of fixing allele frequencies even if they are not known is the common approach to power calculations. We show that ignoring the sources of variation in allele frequencies tends to result in overestimates of power and, consequently, in studies that are underpowered. Software in C is available at http://www.ambrosius.net/Power/. PMID:15024689

Ambrosius, Walter T.; Lange, Ethan M.; Langefeld, Carl D.

2004-01-01

403

Personnel safety requirements for electric distribution systems with dispersed storage and generation  

Microsoft Academic Search

Safety practices and hardware currently employed by electric utilities in electric distribution systems have evolved based on the central production of electric power and delivery of that power to dispersed loads. This evolution has provided for a unidirectional flow of electric power from generation level to loads. The interconnection of dispersed storage and generation (DSG) devices, such as wind-powered ac

Rizy

1982-01-01

404

Space station electrical power distribution analysis using a load flow approach  

NASA Technical Reports Server (NTRS)

The space station's electrical power system will evolve and grow in a manner much similar to the present terrestrial electrical power system utilities. The initial baseline reference configuration will contain more than 50 nodes or busses, inverters, transformers, overcurrent protection devices, distribution lines, solar arrays, and/or solar dynamic power generating sources. The system is designed to manage and distribute 75 KW of power single phase or three phase at 20 KHz, and grow to a level of 300 KW steady state, and must be capable of operating at a peak of 450 KW for 5 to 10 min. In order to plan far into the future and keep pace with load growth, a load flow power system analysis approach must be developed and utilized. This method is a well known energy assessment and management tool that is widely used throughout the Electrical Power Utility Industry. The results of a comprehensive evaluation and assessment of an Electrical Distribution System Analysis Program (EDSA) is discussed. Its potential use as an analysis and design tool for the 20 KHz space station electrical power system is addressed.

Emanuel, Ervin M.

1987-01-01

405

Integrated Computing, Communication, and Distributed Control of Deregulated Electric Power Systems  

SciTech Connect

Restructuring of the electricity market has affected all aspects of the power industry from generation to transmission, distribution, and consumption. Transmission circuits, in particular, are stressed often exceeding their stability limits because of the difficulty in building new transmission lines due to environmental concerns and financial risk. Deregulation has resulted in the need for tighter control strategies to maintain reliability even in the event of considerable structural changes, such as loss of a large generating unit or a transmission line, and changes in loading conditions due to the continuously varying power consumption. Our research efforts under the DOE EPSCoR Grant focused on Integrated Computing, Communication and Distributed Control of Deregulated Electric Power Systems. This research is applicable to operating and controlling modern electric energy systems. The controls developed by APERC provide for a more efficient, economical, reliable, and secure operation of these systems. Under this program, we developed distributed control algorithms suitable for large-scale geographically dispersed power systems and also economic tools to evaluate their effectiveness and impact on power markets. Progress was made in the development of distributed intelligent control agents for reliable and automated operation of integrated electric power systems. The methodologies employed combine information technology, control and communication, agent technology, and power systems engineering in the development of intelligent control agents for reliable and automated operation of integrated electric power systems. In the event of scheduled load changes or unforeseen disturbances, the power system is expected to minimize the effects and costs of disturbances and to maintain critical infrastructure operational.

Bajura, Richard; Feliachi, Ali

2008-09-24

406

An Encoding Technique for Multiobjective Evolutionary Algorithms Applied to Power Distribution System Reconfiguration  

PubMed Central

Network reconfiguration is an alternative to reduce power losses and optimize the operation of power distribution systems. In this paper, an encoding scheme for evolutionary algorithms is proposed in order to search efficiently for the Pareto-optimal solutions during the reconfiguration of power distribution systems considering multiobjective optimization. The encoding scheme is based on the edge window decoder (EWD) technique, which was embedded in the Strength Pareto Evolutionary Algorithm 2 (SPEA2) and the Nondominated Sorting Genetic Algorithm II (NSGA-II). The effectiveness of the encoding scheme was proved by solving a test problem for which the true Pareto-optimal solutions are known in advance. In order to prove the practicability of the encoding scheme, a real distribution system was used to find the near Pareto-optimal solutions for different objective functions to optimize. PMID:25401144

Guardado, J. L.; Rivas-Davalos, F.; Torres, J.; Maximov, S.; Melgoza, E.

2014-01-01

407

Empirical analysis on the connection between power-law distributions and allometries for urban indicators  

E-print Network

We report on the existing connection between power-law distributions and allometries. As it was first reported in [PLoS ONE 7, e40393 (2012)] for the relationship between homicides and population, when these urban indicators present asymptotic power-law distributions, they can also display specific allometries among themselves. Here, we present an extensive characterization of this connection when considering all possible pairs of relationships from twelve urban indicators of Brazilian cities (such as child labour, illiteracy, income, sanitation and unemployment). Our analysis reveal that all our urban indicators are asymptotically distributed as power laws and that the proposed connection also holds for our data when the allometric relationship displays enough correlations. We have also found that not all allometric relationships are independent and that they can be understood as a consequence of the allometric relationship between the urban indicator and the population size. We further show that the residua...

Alves, Luiz G A; Lenzi, Ervin K; Mendes, Renio S

2014-01-01

408

Power density distribution and associated thermal analysis of an elliptical polarizing undulator  

NASA Astrophysics Data System (ADS)

The Taiwan Photon Source (TPS) project is planning to construct a third-generation synchrotron accelerator in Taiwan. This 3 GeV, 500 mA high-energy accelerator will support 20 beamlines for insertion devices (ID) and 24 beamlines for bending magnets (BM). We will undertake an in-depth investigation of the power density distribution and thermal analysis of the accelerator as an important part in the design of the photon absorbers, masks, and mirrors at the front end and in the beamline areas. An elliptically polarizing undulator (EPU) will be one of the primary ID sources for this accelerator and will have a different power density distribution from the other sources. We have derived a general elliptical polarizing EPU power density distribution for this source and have performed a mathematical approximation suitable for practical engineering applications. We will also present a thermal analysis of the helical undulator using Gaussian and unit step-function approximations.

Sheng, I. C.; Kuan, C. K.

2011-04-01

409

Space-based solar power generation using a distributed network of satellites and methods for efficient space power transmission  

NASA Astrophysics Data System (ADS)

Space-based solar power (SSP) generation is being touted as a solution to our ever-increasing energy consumption and dependence on fossil fuels. Satellites in Earth's orbit can capture solar energy through photovoltaic cells and transmit that power to ground based stations. Solar cells in orbit are not hindered by weather, clouds, or night. The energy generated by this process is clean and pollution-free. Although the concept of space-based solar power was initially proposed nearly 40 years ago, the level of technology in photovoltaics, power transmission, materials, and efficient satellite design has finally reached a level of maturity that makes solar power from space a feasible prospect. Furthermore, new strategies in methods for solar energy acquisition and transmission can lead to simplifications in design, reductions in cost and reduced risk. This paper proposes using a distributed array of small satellites to collect power from the Sun, as compared to the more traditional SSP design that consists of one monolithic satellite. This concept mitigates some of SSP's most troublesome historic constraints, such as the requirement for heavy lift launch vehicles and the need for significant assembly in space. Instead, a larger number of smaller satellites designed to collect solar energy are launched independently. A high frequency beam will be used to aggregate collected power into a series of transmission antennas, which beam the energy to Earth's surface at a lower frequency. Due to the smaller power expectations of each satellite and the relatively short distance of travel from low earth orbit, such satellites can be designed with smaller arrays. The inter-satellite rectenna devices can also be smaller and lighter in weight. Our paper suggests how SSP satellites can be designed small enough to fit within ESPA standards and therefore use rideshare to achieve orbit. Alternatively, larger versions could be launched on Falcon 9s or on Falcon 1s with booster stages. The only satellites that are constrained to a significant mass are the beam-down satellites, which still require significant transmission arrays to sufficiently focus the beams targeting corresponding ground stations. With robust design and inherent redundancy built-in, power generation and transmission will not be interrupted in the event of mishaps like space debris collision. Furthermore, the "plug and play" nature of this system significantly reduces the cost, complexity, and risk of upgrading the system. The distributed nature of smallsat clusters maximizes the use of economies of scale. This approach retains some problems of older designs and introduces additional ones. Mitigations will be explored further. For example, the distributed nature of the system requires very precise coordination between and among satellites and a mature attitude control and determination system. Such a design incorporates multiple beaming stages, which has the potential to reduce overall system efficiency. Although this design eliminates the need for space assembly, it retains the challenge of significant on-orbit deployment of solar and transmission arrays. Space power "beaming" is a three step process that involves: 1) conversion of dc power generated by solar cells on the satellite into an electromagnetic wave of suitable frequency, 2) transmission of that wave to power stations on ground, and 3) conversion of the radio waves back into dc power. A great deal of research has been done on the use of microwaves for this purpose. Various factors that affect efficient power generation and transmission will be analyzed in this paper. Based on relevant theory and performance and optimization models, the paper proposes solutions that will help make space-based solar power generation a practical and viable option for addressing the world's growing energy needs.

McLinko, Ryan M.; Sagar, Basant V.

2009-12-01

410

Ion distribution and electronic stopping power for Au ions in silicon carbide  

NASA Astrophysics Data System (ADS)

Accurate knowledge of ion distribution and electronic stopping power for heavy ions in light targets is highly desired due to the large errors in prediction by the widely used Stopping and Range of Ions in Matter (SRIM) code. In this study, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) are used as complementary techniques to determine the distribution of Au ions in SiC with energies from 700 keV to 15 MeV. In addition, a single ion technique with an improved data analysis procedure is applied to measure the electronic stopping power for Au ions in SiC with energies up to ˜70 keV/nucleon. Large overestimation of the electronic stopping power is found by SRIM prediction in the low energy regime up to ˜50 keV/nucleon. The stopping power data and the ion ranges are crosschecked with each other and a good agreement is achieved.

Jin, K.; Zhang, Y.; Xue, H.; Zhu, Z.; Weber, W. J.

2013-07-01

411

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

SciTech Connect

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

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

2012-08-20

412

Study on ac losses of HTS coil carrying ac transport current  

NASA Astrophysics Data System (ADS)

Ac loss has an important influence on the thermal performances of HTS coil. It is necessary to quantify ac loss to ascertain its impact on coil stability and for sizing the coil refrigeration system. In this paper, we analyzed in detail the ac loss components, hysteresis loss, eddy loss and flux flow loss in the pancake HTS coil carrying ac transport current by finite element method. We also investigated the distribution of the ac losses in the coil to study the effects of magnetic field distribution on ac losses.

Dai, Taozhen; Tang, Yuejin; Li, Jingdong; Zhou, Yusheng; Cheng, Shijie; Pan, Yuan

2005-10-01

413

DQ-transformation approach for modelling and stability analysis of AC-DC power system with controlled PWM rectifier and constant power loads  

Microsoft Academic Search

In this paper a technique for analysing aircraft frequency wild power systems with constant power loads is developed and demonstrated. Power electronic based loads often behave as constant power loads, especially when feeding machine or actuator drives under current and speed control. The constant power (CP) loads can affect the stability of the power system. The problem is a particular

K.-N. Areerak; S. V. Bozhko; G. M. Asher; D. W. P. Thomas

2008-01-01

414

The column density distribution of the Lyman-alpha forest: A measure of small scale power  

SciTech Connect

Absorption lines in the Ly{alpha} forest can be thought of as peaks in neutral hydrogen density along lines of sight. The column density distribution (the number density of absorption lines as a function of column density) is then a statistic of density peaks, which contains information about the underlying power spectrum. In particular, we show that the slope of the distribution provides a measure of power on scales smaller than those probed by studies of present day large scale structure. 2 refs., 1 fig.

Hui, Lam [Fermi National Accelerator Lab., Batavia, IL (United States); Gnedin, Nickolay Y. [Astronomy Dept., California Univ., Berkeley, CA (United States); Zhang, Yu [Illinois Univ., Urbana, IL (United States)

1997-02-19

415

Power distributions in fresh and depleted LEU and HEU cores of the MITR reactor.  

SciTech Connect

The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. It delivers a neutron flux comparable to current LWR power reactors in a compact 6 MW core using Highly Enriched Uranium (HEU) fuel. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context, most research and test reactors both domestic and international have started a program of conversion to the use of Low Enriched Uranium (LEU) fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (UMo) is expected to allow the conversion of U.S. domestic high performance reactors like the MITR-II reactor. Toward this goal, core geometry and power distributions are presented. Distributions of power are calculated for LEU cores depleted with MCODE using an MCNP5 Monte Carlo model. The MCNP5 HEU and LEU MITR models were previously compared to experimental benchmark data for the MITR-II. This same model was used with a finer spatial depletion in order to generate power distributions for the LEU cores. The objective of this work is to generate and characterize a series of fresh and depleted core peak power distributions, and provide a thermal hydraulic evaluation of the geometry which should be considered for subsequent thermal hydraulic safety analyses.

Wilson, E.H.; Horelik, N.E.; Dunn, F.E.; Newton, T.H., Jr.; Hu, L.; Stevens, J.G. (Nuclear Engineering Division); (2MIT Nuclear Reactor Laboratory and Nuclear Science and Engineering Department)

2012-04-04

416

Development of a PSCAD\\/EMTDC Model Component for AC Loss Characteristic Analysis of HTS Power Cable  

Microsoft Academic Search

Although Electromagnetic power transient analysis software (PSCAD\\/EMTDC) is one of the useful simulation tools, it does not provide a High Temperature Superconducting (HTS) power cable component, which has the same impedance characteristic of a real HTS power cable. The authors have already proposed a model component of the HTS power cable under the fault condition and simulated power system including

Jin Geun Kim; A.-Rong Kim; Daewon Kim; In-Keun Yu; Jeonwook Cho; Ki-Deok Sim; Seokho Kim; Jun Kyoung Lee; Young-Jin Won

2010-01-01

417

Short-term load forecasting based capacity check for automated power restoration of electric distribution networks  

Microsoft Academic Search

This paper concerns power restoration control in an electric distribution network after a permanent fault. It describes a process for online estimation of loads in a network, which further enables determination of the pre-fault load. The pre-fault load is used to adjust short-term forecasting based load profiles, which are then used in capacity check algorithm of the power restoration controller

Vaibhav Donde; Zhenyuan Wang; Fang Yang; James Stoupis

2010-01-01

418

Species-area relationship for power-law species abundance distribution  

Microsoft Academic Search

We studied the mathematical relations between species abundance distributions (SADs) and species-area relationships (SARs) and found that a power-law SAR can be generally derived from a power-law SAD without a special assumption such as the ``canonical hypothesis''. In the present analysis, an SAR-exponent is obtained as a function of an SAD-exponent for a finite number of species. We also studied

Haruyuki Irie; Kei Tokita

2006-01-01

419

The research of Power Electronic Transformer (PET) in Smart distribution network  

Microsoft Academic Search

The transformers have been widely used in traditional power system, the primary functions of which are voltage-transformation, isolation and energy-transfer. Now with the development of Smart-Grid, power system requires an increasing penetration of the renewable energy resources and other distributed generations around loads, and an active role for DSOs in controlling the network stability, optimizing central and security. Owing to

Zhibing Wang; Kunshan Yu

2010-01-01

420

Advanced electrical power, distribution and control for the Space Transportation System  

NASA Technical Reports Server (NTRS)

High frequency power distribution and management is a technology ready state of development. As such, a system employs the fewest power conversion steps, and employs zero current switching for those steps. It results in the most efficiency, and lowest total parts system count when equivalent systems are compared. The operating voltage and frequency are application specific trade off parameters. However, a 20 kHz Hertz system is suitable for wide range systems.

Hansen, Irving G.; Brandhorst, Henry W., Jr.

1990-01-01

421

New Development of Power Distribution System Resulting from Dispersed Generations and Current Interruption  

NASA Astrophysics Data System (ADS)

Dispersed generation systems, such as micro gas-turbines and fuel cells, have been installed on some of commercial facilities. Smaller dispersed generators like solar photovoltaics have been also located on the several of individual homes. The trends in the introduction of the these generation systems seem to continue in the future and to cause the power system to have the enormous number of the dispersed generation systems. The present report discusses the near-future power distribution systems.

Yokomizu, Yasunobu

422

Advanced electrical power, distribution and control for the Space Transportation System  

NASA Astrophysics Data System (ADS)

High frequency power distribution and management is a technology ready state of development. As such, a system employs the fewest power conversion steps, and employs zero current switching for those steps. It results in the most efficiency, and lowest total parts system count when equivalent systems are compared. The operating voltage and frequency are application specific trade off parameters. However, a 20 kHz Hertz system is suitable for wide range systems.

Hansen, Irving G.; Brandhorst, Henry W., Jr.

1990-08-01

423

Robust statistical tests of Dragon-Kings beyond power law distributions  

NASA Astrophysics Data System (ADS)

We ask the question whether it is possible to diagnose the existence of "Dragon-Kings" (DK), namely anomalous observations compared to a power law background distribution of event sizes. We present two new statistical tests, the U-test and the DK-test, aimed at identifying the existence of even a single anomalous event in the tail of the distribution of just a few tens of observations. The DK-test in particular is derived such that the p-value of its statistic is independent of the exponent characterizing the null hypothesis, which can use an exponential or power law distribution. We demonstrate how to apply these two tests on the distributions of cities and of agglomerations in a number of countries. We find the following evidence for Dragon-Kings: London in the distribution of city sizes of Great Britain; Moscow and St-Petersburg in the distribution of city sizes in the Russian Federation; and Paris in the distribution of agglomeration sizes in France. True negatives are also reported, for instance the absence of Dragon-Kings in the distribution of cities in Germany.

Pisarenko, V. F.; Sornette, D.

2012-05-01

424

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

E-print Network

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 an analytical procedure based in the power distribution system voltage and current transfer matrices is derived

Catholic University of Chile (Universidad Católica de Chile)

425

An AC\\/DC\\/AC Interface Control Strategy to Improve Wind Energy Economics  

Microsoft Academic Search

A control strategy for an AC\\/DC\\/AC interface to smooth or limit wind farm output is investigated. The need to follow rapid power variation from uncontrolled wind farms with expensive gas turbines limits the amount of penetration of wind energy systems in existing utilities. An AC\\/DC\\/AC interface makes it possible to limit the power variations from the wind farm. An optimal

An-Jen Shi; James Thorp; Robert Thomas

1985-01-01

426

Improved Power System of the Future  

E-print Network

This paper is intended to provide an insight into physics and engineering that can modernize electric power systems. Topics covered are Flexible ac transmission systems (FACTS), Custom Power, Greatly improved Capacitors, Electrical Insulation, Distribution Cables, Improved Polymeric Insulation, Underground Vault Explosions, Fault Location, Smart Cables, Neutral and Ground, Corrosion and Protection, Conventional Transformers, Compact Transformers, Ferroresonance, and Solid State Transformers.

Mario Rabinowitz

2003-04-22

427

Universal scaling of dissolved oxygen distribution at the sediment-water interface: A power law  

Microsoft Academic Search

Dissolved oxygen (DO) distribution at the sediment-water interface of a flow over a smooth bed is investigated for Reynolds numbers .360 and ,4,090. These conditions are commonly encountered in streams, wetlands, and lakes. A power-law scaling of DO distribution is derived and compared with experimental data. The scaling analysis is based on DO flux at the sediment-water interface in a

Miki Hondzo; Tom Feyaerts; Richard Donovan; Ben L. O'Connor

2005-01-01

428

Outage Rates of Power Distribution Lines due to Summer and Winter Lightning in Chugoku Region  

NASA Astrophysics Data System (ADS)

Taking the densities of lightning strokes and electric poles into account, we calculated outage rates of each equipment on a 6.6kV distribution line due to summer (Mar.-Oct.) and winter (Nov.-Feb.) lightning for 6 years in the Chugoku region located in the western part of Japan. Furthermore, using these results, we proposed some application maps for the lightning risk assessment of power distribution lines in this region considering the effect of seasonal lightning hazard.

Takahashi, Akihisa; Asakawa, Akira; Yokoyama, Shigeru; Marumoto, Shin-Ichi; Yamamoto, Kousuke; Nakamoto, Susumu

429

The HEMP (high altitude electromagnetic pulse) response of an overhead power distribution line  

SciTech Connect

A study of the HEMP response of a realistic power distribution system was undertaken, and its results are described in this paper. This study involved the following elements: (1) the use of the new HEMP environment, (2) the use of a multiconductor coupling model, and (3) the measurement of the pulse response of an actual distribution transformer to permit the use of this data in the analysis.

Tesche, F.M.; Barnes, P.R.

1988-01-01

430

Small-Signal Modeling and Analysis of Parallel-Connected Power Converter Systems for Distributed Energy Resources  

Microsoft Academic Search

Alternative energy resources (such as photovoltaics, fuel cells, wind turbines, micro-turbines, and internal combustion engines) and energy storage systems (such as batteries, supercapacitors, and flywheels) are increasingly being connected to the utility grid, creating distributed energy resources which require the implementation of an effective distributed power management strategy. Parallel-connected power converters form a critical component in such a distributed energy

Yu Zhang

2011-01-01

431

High-performance programmable AC power source with low harmonic distortion using DSP-based repetitive control technique  

Microsoft Academic Search

This paper proposes a new control scheme based on a two-layer control structure to improve both the transient and steady-state responses of a closed-loop regulated pulse-width-modulated (PWM) inverter for high-quality sinusoidal AC voltage regulation. The proposed two-layer controller consists of a tracking controller and a repetitive controller. Pole assignment with state feedback has been employed in designing the tracking controller

Ying-Yu Tzou; Rong-Shyang Ou; Shih-Liang Jung; Meng-Yueh Chang

1997-01-01

432

Circuit Breaker Technologies for Advanced Ship Power Systems  

Microsoft Academic Search

The AC power systems on navy ships use circuit breakers based on traditional commercial technology. New naval power systems employ higher voltage DC distribution and use solid state power converters that actively (and instantaneously) limit the available fault current. When conventional circuit breakers are used in these systems, they have a relatively long clearing time, causing the voltage to collapse

Slobodan Krstic; Edward L. Wellner; Ashish R. Bendre; Boris Semenov

2007-01-01

433

Remote power feeding-report from a field trial  

Microsoft Academic Search

Remote power feeding (RPF) is a new way of achieving cost efficient back up for telecom. By remote power feeding, AC power is generated centrally and distributed via separate dedicated lines to telecom sites located within a reasonably limited area. Great savings are possible by decreasing the amount of batteries needed at every telecom location, and limiting the numbers of

S.-E. Soderberg; J. Akerlund

1998-01-01

434

Space Station Power System issues  

NASA Technical Reports Server (NTRS)

A number of attractive options are available for the Space Station Power System. These include a photovoltaic system or solar dynamic system for power generation, batteries or fuel cells for energy storage and ac or dc for power management and distribution. These options are being explored during the present preliminary design and definition phase of the Space Station Program. Final selections are presently targeted for January 1986.

Forestieri, A. F.

1985-01-01

435

The Integrated Solar Upper Stage engine ground demonstration power management and distribution subsystem design  

NASA Astrophysics Data System (ADS)

The National Aeronautics and Space Administration (NASA), the Air Force Phillips Laboratory (PL), and the Defense Special Weapons Agency (DSWA) in a joint effort are developing technologies for a solar bimodal system. A solar bimodal system combines thermal propulsion and electric power generation in a single integrated system. A spacecraft Integrated Solar Upper Stage (ISUS) bimodal system combines orbital transfer propulsion, electric power generation, and on-board propulsion into one overall system. A key benefit of such integrated system is the augmentation of payload to spacecraft mass ratio thus resulting in lower launch vehicle requirements. Scaling down to smaller launch vehicles increases space access by reducing overall mission cost. The NASA/PL/DSWA ISUS program is concentrating efforts on a near-term ground test demonstration of the bimodal concept. A successful ground demonstration of the ISUS various technologies will enable a full system flight demonstration of the bimodal concept. NASA Lewis Research Center in Cleveland Ohio will be the site for the engine ground demonstrator (EGD). The ISUS bimodal system uses solar concentrators to focus solar energy into an integrated receiver, absorber, and converter (RAC) power plant. The power plant main body is a graphite blackbody that stores thermal energy within a cavity in its main core. During the propulsion phase of the bimodal system a propellant flows into the graphite main core and is distributed uniformly through axial flow channels in the heated cavity. The blackbody core heats the propellant that is then discharged into an output tube thus creating thrust. An array of thermionic generators encircles the graphite core cavity and provides electrical energy conversion functions during the power generation phase. The power management and distribution subsystem's main functions are to condition raw electrical power generated by the RAC power plant and deliver it to the spacecraft payloads. This paper presents a detail description of the power management and distribution subsystem design for the ISUS ground demonstration program.

Baez, Anastacio N.; Kimnach, Greg L.

1997-01-01

436

Thermal power systems, point-focusing distributed receiver technology project. Volume 2: Detailed report  

NASA Technical Reports Server (NTRS)

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver technology is the goal of this Project. The energy thus produced must be economically competitive with other sources. The Project supports the industrial development of technology and hardware for extracting energy from solar power to achieve the stated goal. Present studies are working to concentrate the solar energy through mirrors or lenses, to a working fluid or gas, and through a power converter change to an energy source useful to man. Rankine-cycle and Brayton-cycle engines are currently being developed as the most promising energy converters for our near future needs.

Lucas, J.

1979-01-01

437

A Regional Demand Forecast by NN Method for Distributed Autonomous Voltage and Reactive Power Control System  

NASA Astrophysics Data System (ADS)

This paper describes technology required for advanced intelligent voltage and reactive secondary control systems enabling co-ordination of voltage control between main and local power systems. Firstly, the paper describes the general structure of a power system control and the concept of a proposed autonomous voltage and reactive power control system. Then, the paper comments on the inadequate behavior of voltage and reactive power control systems, such as up-and-down fluctuations, which sometimes occur during off-peak load times, and explains the reasons for voltage fluctuations. The capacity of distributed generation is increasing in accordance with deregulation of electric supply. In order to enhance voltage stability of power system, the voltage control system requires the more detail information and data of its local network systems, such as local demand forecast, distributed generation and characteristics of power systems. The paper briefly describes two previously developed intelligent component functions, namely, flexible feed forward control to prevent voltage fluctuation, and on-line acquisition of voltage characteristics by neural network technology. The paper describes local demand forecasting one or two hours in advance by the NN method. This method is also applicable to the forecast of the total demand of a power system.

Suzuki, Osamu; Wu, Guohong; Minakawa, Tamotsu

438

Evidence for power-law tail of the wealth distribution in India  

NASA Astrophysics Data System (ADS)

The higher-end tail of the wealth distribution in India is studied using recently published lists of the wealth of richest Indians between the years 2002-2004. The resulting rank distribution seems to imply a power-law tail for the wealth distribution, with a Pareto exponent between 0.81 and 0.92 (depending on the year under analysis). This provides a comparison with previous studies of wealth distribution, which have all been confined to Western advanced capitalist economies. We conclude with a discussion on the appropriateness of multiplicative stochastic process as a model for asset accumulation, the relation between the wealth and income distributions (we estimate the Pareto exponent for the latter to be around 1.5 for India), as well as possible sources of error in measuring the Pareto exponent for wealth.

Sinha, Sitabhra

2006-01-01

439

Modeling and simulation requirements for the analysis and design of DC distributed power electronic systems  

Microsoft Academic Search

The objective of this paper is to establish which are the requirements of the component models in a distributed power system in order to satisfy the necessities of the system architect. Based on the information that will help the designer to make the right decision for its architecture and the selection of their components, different levels of modeling will be

J. A. Oliver; R. Prieto; L. Laguna; J. A. Cobos

2008-01-01

440

Distributed mini power plants for Lebanon: A simulation design using MATLAB\\/SIMULINK  

Microsoft Academic Search

Lebanon has spent billions of dollars on its electricity sector, but the demand is higher than available power. In peak demand time, blackouts are the major phenomena in almost all the Lebanese regions. As the world today is going into green energy, this project lunches the idea of implementing hybrid-renewable distributed energy systems in Lebanon either by individuals or by

Maged B. Najjar; E. Ghoulam; H. Fares

2011-01-01

441

Investigation of the Influence of Leakage Current on Wooden Poles for High Voltage Power Distribution Line  

Microsoft Academic Search

In Australia and many other countries of the world, Power transmission lines on the distribution level are carried mainly on wooden poles. The deposition of pollution is an unavoidable phenomenon in all overhead transmission lines. On a new insulator, which has a high surface resistivity, the leakage current is usually low and primarily capacitive. When pollution builds up on the

Sachin Pathak

442

Do Hegemons Distribute Private Goods?: A Test of Power-Transition Theory  

ERIC Educational Resources Information Center

According to power-transition theory, war is most likely when the leading state is challenged by a rapidly growing, dissatisfied rival. Challengers are said to be dissatisfied because the hegemon manages the status quo for its own benefit, rewarding its allies and penalizing rivals. We assess the leading state's ability to distribute the private…

Bussmann, Margit; Oneal, John R.

2007-01-01

443

Improved target impedance and IC transient current measurement for power distribution network design  

Microsoft Academic Search

An improved definition of target impedance is proposed in this paper, which is derived from the time-domain waveforms of the IC transient current and the allowable voltage fluctuation. The proposed target impedance removes the unnecessary constraint in the original definition and allows for more cost-effective power distribution network (PDN) designs for consumer electronic products. A measurement procedure to obtain IC

Jingook Kim; Songping Wu; Hanfeng Wang; Yuzou Takita; Hayato Takeuchi; Kenji Araki; Gang Feng; Jun Fan

2010-01-01

444

HEMP (High Altitude Electromagnetic Pulse) Response of an Overhead Power Distribution Line.  

National Technical Information Service (NTIS)

A study of the HEMP response of a realistic power distribution system was undertaken, and its results are described in this paper. This study involved the following elements: (1) the use of the new HEMP environment, (2) the use of a multiconductor couplin...

F. M. Tesche, P. R. Barnes

1988-01-01

445

Remaining Service Life Diagnostic Technology of Insulators for Power Distribution Equipment  

Microsoft Academic Search

We have developed a remaining service life diagnostic technology for insulators, which are important parts involved in determining the service life of power distribution equipment. Application of chemical evaluation and the Mahalanobis-Taguchi method enabled us to diagnose the insulators' degree of deterioration with great accuracy and nondestructively on-site. The theory, which derives the threshold value of surface resistivity for electric

Shinsuke Miki; Hiroshi Okazawa; Taketoshi Hasegawa; Sei Tsunoda; Hiroshi Inujima

2007-01-01

446

Remaining service life diagnostic technology of phenol insulators for power distribution equipment  

Microsoft Academic Search

We have applied a remaining service life diagnostic technology to phenol insulators of power distribution equipment. Application of chemical evaluation and the Mahalanobis-Taguchi (MT) method enabled us to diagnose the insulators' degree of deterioration with great accuracy and nondestructively on-site. Time was defined as the end of service life when electrical discharge was initiated and a remaining service life was

S. Miki; T. Hasegawa; S. Umemura; H. Okazawa; Y. Otsuka; H. Inujima

2007-01-01

447

Ozone's effects on power-law particle size distribution in recirculating aquaculture systems  

Microsoft Academic Search

A power law model for particle size distributions has been applied by several researchers to aquacultural and aquatic systems Rueter and Johnson [Aquacult. Eng. 14 (1995) 123] demonstrated that ozonation of trout hatchery water increased the proportion of large particles in the water. Summerfelt et al. [Aquaculture 158 (1997) 57] speculated that this increase in particle size led to their

Valdis Krumins; James M. Ebeling; Fred Wheaton

2001-01-01

448

Power Distribution Outage Cause Identification using Fuzzy Artificial Immune Recognition Systems (FAIRS) algorithm  

Microsoft Academic Search

Power distribution systems have been significantly affected by many events. Effective outage cause identification can help expedite the restoration procedure and improve the system reliability. Fuzzy classification E-algorithm and biological immune system based AIRS algorithm have demonstrated good capability in outage cause identification especially with imbalanced data, E-algorithm can produce inference rules but is computational demanding; AIRS has the quick

Le Xu; Mo-Yuen Chow; Jon Timmis

2007-01-01

449

A Distributed Power Control Algorithm For Bursty Transmissions On Cellular, Spread Spectrum Wireless Networks  

Microsoft Academic Search

We propose a distributed algorithm for power control in cellular, wideband networks forbursty traffic sources, such as data and speech with silence detection. The algorithm adaptspower at mobiles on the basis of only local measurements of the mean and variance of theinterference. The first part of the paper introduces a probabilistic quality of service specificationand gives an asymptotic framework for

Debasis Mitra; John A. Morrison

1996-01-01

450

Coordination of transmission and distribution planning and operations to maximise efficiency in future power systems  

Microsoft Academic Search

Transmission and distribution networks have been historically planned and operated as almost two separate entities. Future power networks will provide a new framework where this practice will no longer be desirable or possible. In particular, achieving maximum efficiency in planning and operating the transmission system requires the consideration, and possible coordination and exchange, of functions, services and information across the

L. Castanheira; G. Ault; M. Cardoso; J. McDonald; J. B. Gouveia; Z. Vale

2005-01-01

451

Distributed Internet-based Load Altering Attacks against Smart Power Grids  

E-print Network

by them. Our simulation results based on the standard setting in the IEEE 24- bus Reliability Test SystemDistributed Internet-based Load Altering Attacks against Smart Power Grids Amir-Hamed Mohsenian-attacks against consumption sector. cities [3]. Detailed discussions on possible defence mecha- nisms against Type

Mohsenian-Rad, Hamed

452

LED lighting module design based on a prescribed candle-power distribution for uniform illumination  

Microsoft Academic Search

A simple approach is presented to design an LED lighting module to provide a uniform illumination. The reflector of the module is designed using a prescribed candle-power distribution to achieve a uniform illumination on a target surface. Both the design methodology and the construction of the reflector are stated in detail. The optical efficiency and uniformity of the module are

Jin-Jia Chen; Kuang-Lung Huang; Te-Yuan Wang; Yi-Chih Wang; Chuen-Ching Wang; Tsung-Yi Guo

2010-01-01

453

Noise Amplitude Distribution of Impulsive Noise from Measurements in a Power Substation  

E-print Network

sources may be far from buildings where measurement equipment can be protected against environmentalNoise Amplitude Distribution of Impulsive Noise from Measurements in a Power Substation Qingshan Shan, Shahzad Bhatti, Ian A Glover, Robert Atkinson, Philip J Moore Dept. of Electronic & Electrical

Atkinson, Robert C

454

Model-Based Diagnosis in a Power Distribution Test-Bed  

NASA Technical Reports Server (NTRS)

The Rodon model-based diagnosis shell was applied to a breadboard test-bed, modeling an automated power distribution system. The constraint-based modeling paradigm and diagnostic algorithm were found to adequately represent the selected set of test scenarios.

Scarl, E.; McCall, K.

1998-01-01

455

Power loss of a single electron charge distribution confined in a quantum plasma  

SciTech Connect

The dielectric tensor for a quantum plasma is derived by using a linearized quantum hydrodynamic theory. The wave functions for a nanostructure bound system have been investigated. Finally, the power loss for an oscillating charge distribution of a mixed state will be calculated, using the dielectric function formalism.

Mehramiz, A. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, East Azerbaijan 51664 (Iran, Islamic Republic of); Department of Physics, Faculty of Science, I. K. Int'l University, Qazvin 34149-16818 (Iran, Islamic Republic of); Mahmoodi, J. [Department of Physics, Faculty of Science, University of Qom, Qom 3716146611 (Iran, Islamic Republic of); Sobhanian, S. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, East Azerbaijan 51664 (Iran, Islamic Republic of)

2011-05-15

456

Control strategies for distributed energy resources to maximize the use of wind power in rural microgrids  

Microsoft Academic Search

This paper investigates the control strategies for distributed energy resources (DERs), including diesel generators, energy storage and demand response (DR), to achieve high penetration of wind energy in a rural microgrid. In such a system, it could be both economical and environmentally friendly to harness wind power and displace the consumption of fossil fuels. In the study, energy storage and

Shuai Lu; Marcelo A. Elizondo; Nader A. Samaan; Karanjit Kalsi; Ebony T. Mayhorn; Ruisheng Diao; Chunlian Jin; Yu Zhang

2011-01-01

457

Utility Grid-Connected Distributed Power Systems National Solar Energy Conference  

E-print Network

the experience needed to successfully integrate PV as distributed generation into the utility system Program uses attractive performance based rebates and financing and strict quality assurance requirements customers have used this program ABSTRACT INTRODUCTION 3/21/04 4:48 PMGreen Power Network: Utility Grid

458

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 new operating conditions, some not seen before, that are lim- ited by fault interruption capability. Increased system fault currents resulting from DG installation and the effects of in- creased fault currents

459

Fault Isolation for Spacecraft Systems: An Application to a Power Distribution  

E-print Network

Fault Isolation for Spacecraft Systems: An Application to a Power Distribution Testbed Joshua D, early fault detection and isolation is essential to maintaining system safety and avoiding catastrophic failures. This paper discusses a fault isolation scheme based on a qualitative fault signature

Koutsoukos, Xenofon D.

460

Control of force distribution for power grasp in the DIGITS system  

Microsoft Academic Search

A linear programming approach is used to formulate and solve the force distribution problem in power grasps. The basic model used is taken from the DIGITS Grasping System, which consists of four three-degree-of-freedom fingers. The program solves for the required joint torques with limits imposed on their maximum value along with limits on contact normal reactions while optimizing an objective

Khalid Mirza; David E. Orin

1990-01-01

461

Fertility heterogeneity as a mechanism for power law distributions of recurrence times  

NASA Astrophysics Data System (ADS)

We study the statistical properties of recurrence times in the self-excited Hawkes conditional Poisson process, the simplest extension of the Poisson process that takes into account how the past events influence the occurrence of future events. Specifically, we analyze the impact of the power law distribution of fertilities with exponent ?, where the fertility of an event is the number of triggered events of first generation, on the probability distribution function (PDF) f(?) of the recurrence times ? between successive events. The other input of the model is an exponential law quantifying the PDF of waiting times between an event and its first generation triggered events, whose characteristic time scale is taken as our time unit. At short-time scales, we discover two intermediate power law asymptotics, f(?)˜?-(2-?) for ???c and f(?)˜?-? for ?c???1, where ?c is associated with the self-excited cascades of triggered events. For 1???1/?, we find a constant plateau f(?)?const, while at long times, 1/???, f(?)?e-?? has an exponential tail controlled by the arrival rate ? of exogenous events. These results demonstrate a novel mechanism for the generation of power laws in the distribution of recurrence times, which results from a power law distribution of fertilities in the presence of self-excitation and cascades of triggering.

Saichev, A.; Sornette, D.

2013-02-01

462

Fertility heterogeneity as a mechanism for power law distributions of recurrence times.  

PubMed

We study the statistical properties of recurrence times in the self-excited Hawkes conditional Poisson process, the simplest extension of the Poisson process that takes into account how the past events influence the occurrence of future events. Specifically, we analyze the impact of the power law distribution of fertilities with exponent ?, where the fertility of an event is the number of triggered events of first generation, on the probability distribution function (PDF) f(?) of the recurrence times ? between successive events. The other input of the model is an exponential law quantifying the PDF of waiting times between an event and its first generation triggered events, whose characteristic time scale is taken as our time unit. At short-time scales, we discover two intermediate power law asymptotics, f(?)~?(-(2-?)) for ?power laws in the distribution of recurrence times, which results from a power law distribution of fertilities in the presence of self-excitation and cascades of triggering. PMID:23496576

Saichev, A; Sornette, D

2013-02-01

463

ENHANCED RECOVERY UTILIZING VARIABLE FREQUENCY DRIVES AND A DISTRIBUTED POWER SYSTEM TECHNICAL PROGRESS REPORT  

SciTech Connect

This report describes the progress made during first six months of the project entitled ''Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System''. During this period, project plan, demonstration plan and project schedule were developed, equipment was ordered and baseline data was collected.

Randy Peden; Sanjiv Shah

2004-02-11

464

Spatiotemporal Load-Analysis Model for Electric Power Distribution Facilities Using Consumer Meter-Reading Data  

Microsoft Academic Search

The load analysis for the distribution system and facilities has relied on measurement equipment. Moreover, load monitoring incurs huge costs in terms of installation and main- tenance. This paper presents a new model to analyze wherein facilities load under a feeder every 15 min using meter-reading data that can be obtained from a power consumer every 15 min or a

Jin-Ho Shin; Bong-Jae Yi; Young-Il Kim; Heon-Gyu Lee; Keun Ho Ryu

2011-01-01

465

TRANSIENT CURRENTSAM) VOLTAGES IN A POWER DISTRIBUTION SYSTEM DUE TO NATURAL LIGHTNING  

E-print Network

TRANSIENT CURRENTSAM) VOLTAGES IN A POWER DISTRIBUTION SYSTEM DUE TO NATURAL LIGHTNING M at Camp Blanding, Florida, during the 1995 and 19% experiments. Transient currents and voltages the test site duringthe 1995and 1996experiments, and its effects on the test system were recorded. On 10

Florida, University of

466

Likelihood ratio tests for linkage and linkage disequilibrium: Asymptotic distribution and power  

SciTech Connect

Terwilliger proposes an interesting likelihood ratio test for linkage disequilibrium that appears conservative under the null hypothesis and powerful when one of several alleles is positively associated with the disease. We discuss in detail the aspects of linkage disequilibrium with a simpler asymptotic distribution. 3 refs.

NONE

1996-05-01

467

Distributed Power System Automation With IEC 61850, IEC 61499, and Intelligent Control  

Microsoft Academic Search

This paper presents new approach to power system automation, based on distributed intelligence rather than traditional centralised control. The paper investigates the interplay between two international standards, IEC 61850 and IEC 61499, and proposes a way of combining of the application functions of IEC 61850-compliant devices with IEC 61499-compliant \\

Neil Higgins; Valeriy Vyatkin; Nirmal-Kumar C. Nair; Karlheinz Schwarz

2011-01-01

468

DC Remote and AC Local Power Feeding of xDSL Networks A real-world deployment experience  

Microsoft Academic Search

Access networks require more and more active equipment to be deployed close to the subscriber, i.e. in locations where no power was available so far. The paper discusses two possible powering solutions, namely DC remote power feeding and local power feeding, weighing their respective advantages from both the technical and economical points of view. The discussion is based on a

S. Cambier; D. Bogaerts

2005-01-01

469

Simulation for light power distribution of 3D InGaN\\/GaN MQW LED with textured surface  

Microsoft Academic Search

In this paper, we introduce a full 3D simulation for light power distribution of an InGaN\\/GaN MQW LED with textured surface. Device simulation was performed by APSYS software to get power distribution of light source inside the LED. Based on this, ray tracing simulation was carried out to get light power distribution outside the LED. During the process of ray

Li-Wen Cheng; Yang Sheng; Chang-Sheng Xia; Wei Lu; M. Lestrade; Zhan-Ming Li

2010-01-01

470

Simulation for light power distribution of 3D InGaN\\/GaN MQW LED with textured surface  

Microsoft Academic Search

In this paper, we introduce a full 3D simulation for light power distribution of an InGaN\\/GaN MQW LED with a textured surface.\\u000a Device simulation was performed with the APSYS software to get power distribution of light sources inside the LED. Based on\\u000a this, ray tracing simulation was carried out to get light power distribution outside the LED. During the process

Li-Wen Cheng; Yang Sheng; Chang-Sheng Xia; Wei Lu; Michel Lestrade; Zhan-Ming Li

471

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

NASA Astrophysics Data System (ADS)

Our interconnected electric power system is presently facing many challenges that it was not originally designed and engineered to handle. The increased inter-area power transfers, aging infrastructure, and old technologies, have caused many problems including voltage instability, widespread blackouts, slow control response, among others. These problems have created an urgent need to transform the present electric power system to a highly stable, reliable, efficient, and self-healing electric power system of the future, which has been termed "smart grid". This dissertation begins with an investigation of voltage stability in bulk transmission networks. A new continuation power flow tool for studying the impacts of generator merit order based dispatch on inter-area transfer capability and static voltage stability is presented. The load demands are represented by lumped load models on the transmission system. While this representation is acceptable in traditional power system analysis, it may not be valid in the future smart grid where the distribution system will be integrated with intelligent and quick control capabilities to mitigate voltage problems before they propagate into the entire system. Therefore, before analyzing the operation of the whole smart grid, it is important to understand the distribution system first. The second part of this dissertation presents a new platform for studying and testing emerging technologies in advanced Distribution Automation (DA) within smart grids. Due to the key benefits over the traditional centralized approach, namely flexible deployment, scalability, and avoidance of single-point-of-failure, a new distributed approach is employed to design and develop all elements of the platform. A multi-agent system (MAS), which has the three key characteristics of autonomy, local view, and decentralization, is selected to implement the advanced DA functions. The intelligent agents utilize a communication network for cooperation and negotiation. Communication latency is modeled using a user-defined probability density function. Failure-tolerant communication strategies are developed for agent communications. Major elements of advanced DA are developed in a completely distributed way and successfully tested for several IEEE standard systems, including: Fault Detection, Location, Isolation, and Service Restoration (FLISR); Coordination of Distributed Energy Storage Systems (DES); Distributed Power Flow (DPF); Volt-VAR Control (VVC); and Loss Reduction (LR).

Nguyen, Cuong Phuc

472

Power law behavior of the isotope yield distributions in the multifragmentation regime of heavy ion reactions  

SciTech Connect

Isotope yield distributions in the multifragmentation regime were studied with high-quality isotope identification, focusing on the intermediate mass fragments (IMFs) produced in semiviolent collisions. The yields were analyzed within the framework of a modified Fisher model. Using the ratio of the mass-dependent symmetry energy coefficient relative to the temperature, a{sub sym}/T, extracted in previous work and that of the pairing term, a{sub p}/T, extracted from this work, and assuming that both reflect secondary decay processes, the experimentally observed isotope yields were corrected for these effects. For a given I=N-Z value, the corrected yields of isotopes relative to the yield of {sup 12}C show a power law distribution Y(N,Z)/Y({sup 12}C){approx}A{sup -}{tau} in the mass range 1{<=}A{<=}30, and the distributions are almost identical for the different reactions studied. The observed power law distributions change systematically when I of the isotopes changes and the extracted {tau} value decreases from 3.9 to 1.0 as I increases from -1 to 3. These observations are well reproduced by a simple deexcitation model, with which the power law distribution of the primary isotopes is determined to be {tau}{sup prim}=2.4{+-}0.2, suggesting that the disassembling system at the time of the fragment formation is indeed at, or very near, the critical point.

Huang, M. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Wada, R.; Hagel, K.; Barbui, M.; Bottosso, C.; Materna, T.; Natowitz, J. B.; Qin, L.; Rodrigues, M. R. D.; Sahu, P. K.; Schmidt, K. J. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Chen, Z. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Keutgen, T. [FNRS and IPN, Universite Catholique de Louvain, B-1348 Louvain-Neuve (Belgium); Kowalski, S. [Institute of Physics, Silesia University, Katowice (Poland); Bonasera, A. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Laboratori Nazionali del Sud, INFN, via Santa Sofia, 62, I-95123 Catania (Italy); Wang, J. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2010-11-15

473

Experimental power density distribution benchmark in the TRIGA Mark II reactor  

SciTech Connect

In order to improve the power calibration process and to benchmark the existing computational model of the TRIGA Mark II reactor at the Josef Stefan Inst. (JSI), a bilateral project was started as part of the agreement between the French Commissariat a l'energie atomique et aux energies alternatives (CEA) and the Ministry of higher education, science and technology of Slovenia. One of the objectives of the project was to analyze and improve the power calibration process of the JSI TRIGA reactor (procedural improvement and uncertainty reduction) by using absolutely calibrated CEA fission chambers (FCs). This is one of the few available power density distribution benchmarks for testing not only the fission rate distribution but also the absolute values of the fission rates. Our preliminary calculations indicate that the total experimental uncertainty of the measured reaction rate is sufficiently low that the experiments could be considered as benchmark experiments. (authors)

Snoj, L.; Stancar, Z.; Radulovic, V.; Podvratnik, M.; Zerovnik, G.; Trkov, A. [Josef Stefan Inst., Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Barbot, L.; Domergue, C.; Destouches, C. [CEA DEN, DER, Instrumentation Sensors and Dosimetry laboratory Cadarache, F-13108 Saint-Paul-Lez-Durance (France)

2012-07-01

474

A MEMS sensor for AC electric current  

NASA Astrophysics Data System (ADS)

This manuscript describes the development of a new MEMS sensor for the measurement of AC electric current. The sensor is comprised of a MEMS piezoelectric cantilever with a microscale permanent magnet mounted to the cantilever's free end. When placed near a wire carrying AC current, the magnet couples to the oscillating magnetic field surrounding the wire, causing the cantilever to deflect, and piezoelectric coupling produces a sinusoidal voltage proportional to the current in the wire. The sensor is itself passive, requiring no power supply to operate. It also operates on proximity and need only be placed near a current carrier in order to function. The sensor does not need to encircle the current carrier and it therefore can measure current in two-wire zip-cords without necessitating the separation of the two conductors. Applications for tins sensor include measuring residential and commercial electricity use and monitoring electric power distribution networks. An analytical model describing the behavior of the current sensor was developed. This model was also adapted to describe the power output of an energy scavenger coupled to a wire carrying AC current. A mesoscale sensor exhibited a sensitivity of 75 mV/A when measuring AC electric current in a zip-cord. A mesoscale energy scavenger produced 345 muW when coupled to a zip-cord carrying 13 A. MEMS current sensors were fabricated from aluminum nitride piezoelectric cantilevers and composite permanent magnets. The cantilevers were fabricated using a four-mask process. Microscale permanent magnets were dispenser-printed using NdFeB magnetic powder with an epoxy binder. The MEMS AC current sensor was interfaced with amplification circuitry and packaged inside an almninum enclosure. The sensor was also integrated with a mesoscale energy scavenger and power conditioning circuitry to create a fully self-powered current sensor. Unamplified sensitivity of the sensor was 0.1-1.1 mV/A when measuring currents in single wires and zip-cords. The self-powered current sensor operated at a 0.6% duty cycle when coupled to the zip-cord of a 1500 W space heater drawing 13 A. The self-powered sensor's energy scavenger transferred energy to a 10 mF storage capacitor at a rate of 69 muJ/s.

Leland, Eli Sidney

475

Advanced Power Electronic Interfaces for Distributed Energy Systems, Part 2: Modeling, Development, and Experimental Evaluation of Advanced Control Functions for Single-Phase Utility-Connected Inverter  

SciTech Connect

Integrating renewable energy and distributed generations into the Smart Grid architecture requires power electronic (PE) for energy conversion. The key to reaching successful Smart Grid implementation is to develop interoperable, intelligent, and advanced PE technology that improves and accelerates the use of distributed energy resource systems. This report describes the simulation, design, and testing of a single-phase DC-to-AC inverter developed to operate in both islanded and utility-connected mode. It provides results on both the simulations and the experiments conducted, demonstrating the ability of the inverter to provide advanced control functions such as power flow and VAR/voltage regulation. This report also analyzes two different techniques used for digital signal processor (DSP) code generation. Initially, the DSP code was written in C programming language using Texas Instrument's Code Composer Studio. In a later stage of the research, the Simulink DSP toolbox was used to self-generate code for the DSP. The successful tests using Simulink self-generated DSP codes show promise for fast prototyping of PE controls.

Chakraborty, S.; Kroposki, B.; Kramer, W.

2008-11-01

476

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

E-print Network

conversion is to be utilized to convert alternating current (AC) generation to direct current (DC) distribution. As state-of-the-art power electronics, the Navy plans to use power electronic building blocks (PEBB) technology in its IPS. A U.S. naval shipboard...

Adediran, Adeoti Taiwo

2004-09-30

477

Distributed and coupled 2D electro-thermal model of power semiconductor devices  

NASA Astrophysics Data System (ADS)

The development of power electronics in the field of transportations (automotive, aeronautics) requires the use of power semiconductor devices providing protection and diagnostic functions. In the case of series protections power semiconductor devices which provide protection may operate in shortcircuit and act as a current limiting device. This mode of operations is very constraining due to the large dissipation of power. In these particular conditions of operation, electro-thermal models 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 based on the coupling between two computation softwares (Matlab and Cast3M) is described in this paper. The 2D electro-thermal model is able to predict (i) the temperature distribution on chip surface well as in the volume under short-circuit operations, (ii) the effect of the temperature on the distribution of the current flowing within the die and (iii) the effects of the ageing of the metallization layer on the current density and the temperature. In this paper, the electrical and thermal models are described as well as the implemented coupling scheme.

Belkacem, Ghania; Lefebvre, Stéphane; Joubert, Pierre-Yves; Bouarroudj-Berkani, Mounira; Labrousse, Denis; Rostaing, Gilles

2014-05-01

478

Power cable fault management with fiber optic distributed sensors: future technological trends  

NASA Astrophysics Data System (ADS)

This paper presents an analysis of fiber distributed sensors applied to power cable fault management, and proposes a more suitable solution for the future. In tomorrow's fast-paced deregulated environment, exploiting new technologies for competitive advantage has become a major incentive in the power business delivery. In power lines, the main parameters that need real time checking are temperature, partial discharges, and mechanical forces. If unchecked, these parameters can seriously damage the insulation system of high-voltage power apparatus and them reduce their life expectancy. This paper deals with these three parameters and presents today's state-of-the-art. The first part analyzes the current situation by pointing out the most commonly used technique for temperature measurement: the anti Stokes Raman back-scattering method. The simple fact that the principle is based on natural or spontaneous light emission as a function of temperature make it work. However, the low signal and its slow response does not allow partial discharge considerations. The second part reviews a new more powerful technique that allows both force and temperature measurements. The principle is based on forward time division multiplexing with a two-guiding region fiber. With a view to emphasizing a specific parameter among the others, distributed temperature sensors using stimulated light amplification in rare earth-doped optical fibers are proposed. If applied, this technique would generate a more usable signal for both temperature measurement and rapid change. All in all, this paper gives a fair insight into power cable total fault management.

Teral, Stephane R.; Kleinerman, Marcos; Malavielle, Patrice

1998-06-01

479

Performance of conventional power flow routines for real-time distribution automation applications  

SciTech Connect

Three iterative techniques for power flow calculations of radial circuits were analyzed in this study to determine their desirability for real-time distribution system applications. The objective was to identify a technique that is fast (preferably using a simple algorithm), accurate (giving good estimates of voltage and power flows), and stable (yielding results for widely varying load conditions). In addition, we were interested in an analysis technique that performs well for radial circuit configurations (since conventional power flow techniques are employed primarily for large transmission network systems), that is able to utilize monitored data such as bus voltages and real and reactive power, and that is able to accomodate system reconfigurations. The Newton-Raphson technique was determined to be the most stable iterative technique for distribution feeder power flow analysis. However, the memory requirements and the computational requirements of the Newton-Raphson technique are excessive for real-time analysis of complex radial circuits. Equivalencing of the detailed radial feeders may be used to simplify the circuits and to improve the performance of the Newton-Raphson technique. Another technique that uses linear equations to solve for bus voltages and power flows combined with data base manipulating capabilities to handle system reconfiguration is being pursued as well.

Stevens, R.A.; Rizy, D.T.; Purucker, S.L.

1986-01-01

480

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

SciTech Connect

It is a well-established fact that geomagnetic storms influence electrical power transmission and distribution systems. Previous cases of such storms in the northern latitudes have resulted in occasional power disruptions, and in some cases, damage to transformers. These effects are caused by a time variation of the earth's magnetic field creating an induced electric field along the surface of the earth. This E-field acts as a voltage source along long power transmission or distribution lines, and if the line is connected to the earth at both ends, a quasi-dc current can flow. This current can cause unwanted saturation in the magnetic cores of transformers in the power system, and this, in turn produces harmonic distortion and transformer heating. This can lead to system upset (shutdown) and possibly transformer burn-out. The detonation of a high altitude nuclear explosion is also known to affect the magnetosphere, producing late-time variations of the earth's magnetic field for several hundreds of seconds. Known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), or E{sub 3}, this environment is of particular concern to electrical power systems in the event of a nuclear attack. Although the MHD-EMP induced currents can be significantly larger in magnitude, they last for a shorter period of time than do those from a geomagnetic storm. The effect of this environment compounds the adverse effects of the early-time high altitude EMP (HEMP) environment, posing a potentially serious threat to the electrical system. The present paper documents an experimental program designed to better understand the behavior of distribution-class transformers subjected to quasi-dc current excitation. Given the knowledge of the MHD-EMP-induced current flowing in a long power line, and the transformer response characteristics obtained in this program, it will be possible to make more accurate assessments of the behavior of the overall power system to EMP. 7 refs., 5 figs.

McConnell, B.W.; Barnes, P.R. (Oak Ridge National Lab., TN (United States)); Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States))

1991-01-01