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1

Ac Power. Generation and Distribution.  

National Technical Information Service (NTIS)

Alternating current power generation and distribution of a square wave voltage in spacecraft was investigated; its feasibility was proved by development of a complete power conditioning system. An evaluation of electromagnetic interference of ac distribut...

W. Denzinger

1975-01-01

2

A review of distributed power systems. Part II. High frequency AC distributed power systems  

Microsoft Academic Search

The present development state in high frequency (HF) AC distributed power systems (DPS) is reviewed. First, background and motivations of developing HF AC-DPS are addressed. Two types of basic HF AC-DPSs based on sine wave and square\\/PWM (pulsewidth modulated) wave bus are described, and the system level design considerations are discussed. Further, the issues and challenges in this research area

SHIGUO LUO; ISSA BATARSEH

2006-01-01

3

A unity power factor resonant AC\\/DC converter for high frequency space power distribution system  

Microsoft Academic Search

This paper presents analysis and design of a resonant AC\\/DC converter topology, suitable for use in an advanced single-phase, sine-wave voltage, high-frequency power distribution system, of the type that was proposed for a 20 kHz Space Station Primary Electrical Power Distribution System. The converter comprises a transformer, a double tuned resonant network comprising of series tuned and parallel tuned branches,

P. Jain; M. C. Tanju

1994-01-01

4

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

Microsoft Academic Search

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

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

1996-01-01

5

Switching strategy for integral cycle converter in a high frequency AC distributed power system  

Microsoft Academic Search

In high frequency AC distributed power systems, the integral cycle converter (ICC) can efficiently synthesize low frequency AC or DC output from the high frequency link by means of soft switching. However for the ICC to operate as a local power module supplying the load, the synthesized voltage will need to be filtered to extract only the desired low frequency

Steven Lourdes; Patrick C. K. Luk; Ken Jinupun

2009-01-01

6

AC/DC Smart Control And Power Sharing of DC Distribution Systems.  

National Technical Information Service (NTIS)

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 conduc...

M. A. Elshaer

2012-01-01

7

A High Efficiency High Frequency Resonant Inverter for High Frequency AC Power Distribution Architectures  

Microsoft Academic Search

A high efficiency two-stage resonant inverter with effective control of both the magnitude and phase angle of the output voltage was proposed in this paper for high frequency AC (HFAC) power distribution applications, where a number of resonant inverters need to be paralleled. In order to parallel multiple resonant inverters of the same operation frequency, each inverter module need independent

Ye Zhongming; Jain Praveen; Sen Paresh

2006-01-01

8

Control of parallel inverters in distributed AC power systems with consideration of line impedance effect  

Microsoft Academic Search

The authors have developed a new control technique which allows paralleled inverters to share linear or nonlinear load in a distributed AC power supply system. This technique does not require control interconnections and automatically compensates for inverter parameter variations and line impedance imbalances. Experimental results are provided in the paper to prove the concept

Anil Tuladhar; Hua Jin; Tom Unger; Konrad Mauch

2000-01-01

9

A unity power factor resonant AC\\/DC converter for high-frequency space power distribution system  

Microsoft Academic Search

This paper presents analysis and design of a resonant AC\\/DC converter topology, suitable for use in an advanced single-phase, sine-wave voltage, high-frequency power distribution system of the type that was proposed for a 20 kHz space station primary electrical power distribution system. The converter comprises a transformer, a double-tuned resonant network comprising of series- and parallel-tuned branches, a controlled rectifier,

P. K. Jain; M. C. Tanju

1997-01-01

10

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

11

AC load conditioner and DC bus conditioner for a DC distribution power system  

Microsoft Academic Search

A PEBB (power electronics building block) based power converter system is described to provide a secondary utility bus in a DC distributed power system on a ship. The power converter system consists of a main inverter and a multi-functional load conditioner to achieve low voltage distortion under unbalanced and\\/or nonlinear loads. A four-legged three-phase power converter topology is used for

R. Zhang; Fred C. Lee; Dushan Boroyevich; Changrong Liu; Lijia Chen

2000-01-01

12

Mathematical Simulation of Power Conditioning Systems. Volume 4: Systems Simulation: Regulated Bus, AC Distribution, MPPT System Simulation Mathematique des Systemes de Conditionnement de Puissance. Simulation des Systemes. Barre Regulee, Distribution Alternative, Systeme Mppt.  

National Technical Information Service (NTIS)

Systems simulations are presented for the regulated bus concept, for the ac distribution system, and for the Maximum Power Point Tracking (MPPT) distribution system. Results show that the regulated bus system performs relatively well both for continuous a...

R. Prajoux J. Mazankine

1976-01-01

13

An ac-ac power converter for custom power applications  

SciTech Connect

A versatile ac-ac converter that can be utilized as a control device for Custom Power applications is presented. The converter has the ability to regulate bus voltage through voltage sags and overvoltages, and act as a solid state circuit breaker. Performance characteristics under typical conditions are presented along with experimental verification of converter operation. Technical feasibility, projected efficiency and other practical implementation issues are discussed. Operation of the power converter is illustrated using EMTP simulations.

Venkataramanan, G. [Montana State Univ., Bozeman, MT (United States). Dept. of Electrical Engineering; Johnson, B.K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering; Sundaram, A. [Electric Power Research Inst., Palo Alto, CA (United States)

1996-07-01

14

Active Filter Technique for the Attenuation of AC Ripple in DC Power Plants and Distribution  

Microsoft Academic Search

Low-pass passive filters used in power converters attenuate low frequency ripple in a very inefficient way. The purpose of this paper is to show how small power active filters can effectively suppress low frequency ripple levels in large power systems. Switchmode power converters with high switching frequency and high gain voltage feedback control have been used as active filters. Three

T. Wolpert

1984-01-01

15

AC Distribution System for TFTR Pulsed Loads.  

National Technical Information Service (NTIS)

This paper outlines the AC distribution system associated with the Tokamak Fusion Test Reactor and discusses the significant areas related to design, protection, and equipment selection, particularly where there is a departure from normal utility and indu...

R. F. Carroll S. Ramakrishnan G. N. Lemmon W. I. Moo

1977-01-01

16

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

NASA Astrophysics Data System (ADS)

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

Shizu, Keiichiro; Azuma, Satoshi

17

Distributed energy resources in grid interactive AC microgrids  

Microsoft Academic Search

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

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

2010-01-01

18

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

19

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food...Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that...

2010-04-01

20

21 CFR 886.4440 - AC-powered magnet.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food...Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that...

2009-04-01

21

The ac power system testbed  

NASA Astrophysics Data System (ADS)

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

Mildice, J.; Sundberg, R.

1987-11-01

22

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

23

Power Control for AC Motor.  

National Technical Information Service (NTIS)

A motor controller employing a triac through which power is supplied to a motor and wherein the open circuit voltage appearing across the triac controls the operation of a timing circuit which triggers on the triac at a time following turn off which varie...

R. W. Dabney

1983-01-01

24

Measurements of AC Losses and Current Distribution in Superconducting Cables  

SciTech Connect

This paper presents our new experimental facility and techniques to measure ac loss and current distribution between the layers for High Temperature Superconducting (HTS) cables. The facility is powered with a 45 kVA three-phase power supply which can provide three-phase currents up to 5 kA per phase via high current transformers. The system is suitable for measurements at any frequency between 20 and 500 Hz to better understand the ac loss mechanisms in HTS cables. In this paper, we will report techniques and results for ac loss measurements carried out on several HTS cables with and without an HTS shielding layer. For cables without a shielding layer, care must be taken to control the effect of the magnetic fields from return currents on loss measurements. The waveform of the axial magnetic field was also measured by a small pick-up coil placed inside a two-layer cable. The temporal current distribution between the layers can be calculated from the waveform of the axial field.

Nguyen, Doan A [Los Alamos National Laboratory (LANL); Ashworth, Stephen P [Los Alamos National Laboratory (LANL); Duckworth, Robert C [ORNL; Carter, Bill [AMSC; Fleshler, Steven [AMER Superconductor Corp, Devens, MA 01434

2011-01-01

25

Stability Study for a Hybrid AC-DC More-Electric Aircraft Power System  

Microsoft Academic Search

The paper deals with the small-signal stability analysis of aircraft ac frequency-wild power systems representing a real ac-dc hybrid distribution architecture with a multiplicity of actuators, aircraft loads, and bus geometries. The $dq$ modelling approach is applied to derive individual power system component models and to constitute the corresponding generalized power system model as a powerful and flexible stability analysis

K. N. Areerak; S. V. Bozhko; G. M. Asher; L. De Lillo; D. W. P. Thomas

2012-01-01

26

Modelling and optimal switching pattern generation for AC to AC power converters  

Microsoft Academic Search

`Thin' power electronics concentrates on the design of minimal and cost effective power converters. Part of the research effort targets the direct processing of an AC input to an AC output without the use of an intermediate DC stage. Particular examples include the inverterless active filter and the controllable network transformer, both of which in their simplest form employ a

Daniel J. Rogers; Deepak M. Divan; Tim C. Green

2010-01-01

27

Advanced concept for dispersed power supply system using AC modules  

Microsoft Academic Search

A method of for estimating the reliability of new conceptual stand-alone dispersed power supply systems using AC modules with self-contained logic was proposed and system reliability estimated using a yearly scale simulation. The AC module is able to supply AC power on each module and has the flexibility to enable construction of a grid-connected system. Power storage devices were required

Naotaka Okada; Kiyoshi Takigawa

2001-01-01

28

Improved power quality three phase AC-DC converter  

Microsoft Academic Search

Because of increasing applications of power electronic ac-dc converters, it's necessary to implement the single stage converter that can reliably perform both buck and boost operations. Traditionally, this can be achieved by double stage conversion (ac\\/dc-dc\\/dc) but ultimately leading to less efficiency and complex control. The novel ac-dc impedance-source converter, abbreviated as Z-source rectifier, has high power quality level and

Seyed Hossein Hosseini; F. Sedaghati; M. Sarhangzadeh

2010-01-01

29

Output power enhancement of ac Raman free-electron laser  

SciTech Connect

The ac free-electron laser (ac FEL) uses an ac (temporally oscillating but spatially uniform) field as the pump source with the hope that electromagnetic radiation will be produced with wavelength shorter than that can be generated by a conventional magnet FEL. The ac field can be provided by a superconducting cavity or by a plasma wave. In this note, the effects of the thermal motion of the electron beam on the linear gain and the nonlinear saturated output power in a Raman-regime ac FEL with the launch of an electromagnetic signal wave by particle-in-cell simulations are investigated. The output power enhancement of the ac FEL either by imposing an appropriate axial electric field at the time of radiation saturation or by properly tapering the strength or the frequency of the ac pump is discussed.

Yan, Y.T.

1987-01-01

30

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

31

High frequency AC vs. DC distribution system for next generation hybrid electric vehicle  

Microsoft Academic Search

The paper proposes and then demonstrates the viability of high frequency AC (HFAC) for propulsion power distribution system in the next generation advanced electric\\/hybrid vehicle. In justifying this viability, the HFAC system has been studied thoroughly and compared with the traditional DC distribution system with regard to cost, weight, performance and other capabilities after performing component sizing calculation of both

B. K. Bose; Min-Huei Kin; M. D. Kankam

1996-01-01

32

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

33

21 CFR 886.1850 - AC-powered slitlamp biomicroscope.  

Code of Federal Regulations, 2013 CFR

...biomicroscope is an AC-powered device that is a microscope intended for use in eye examination that projects into a patient's eye through a control diaphragm a thin, intense beam of light. (b) Classification. Class...

2013-04-01

34

Distribution of AC loss in a HTS magnet for SMES with different operating conditions  

NASA Astrophysics Data System (ADS)

The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

Xu, Y.; Tang, Y.; Ren, L.; Jiao, F.; Song, M.; Cao, K.; Wang, D.; Wang, L.; Dong, H.

2013-11-01

35

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

36

AC losses and current distribution of multi-tape BI-2223 composite conductor  

NASA Astrophysics Data System (ADS)

In the power applications of high temperature superconductor(HTS), it is necessary to stack several HTS tapes together to achieve high current carrying capacity. However, the current would not be well distributed in the multi-tape composites due to the existence of electrical and magnetic interaction inside it. As a result, the AC losses in the composites would be then increased. In order to investigate the detail, the AC losses of multi-tape composites are experimentally studied in this presentation. The average transport AC losses are measured under self and different background AC fields. The results show that the average losses are increased with the external magnetic field and the number of the stacked tapes, and there exists an upper limit of the number of the stacked tapes due to the magnetic coupling effect among the tapes. .

Zhang, G. M.; Lin, L. Z.; Xiao, L. Y.; Qiu, M.; Wang, Y. S.; Yu, Y. J.

2002-05-01

37

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

Microsoft Academic Search

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

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

2003-01-01

38

Reliability assurance program for operational emergency ac power system  

SciTech Connect

A comprehensive review of emergency ac power systems in nuclear generating plants (the vast majority of these plants contain redundant diesel generator systems) delineates several operational areas that can be improved by instituting a reliability assurance program (RAP), which initially upgrades the diesel generator performance and provides for ongoing monitoring and maintenance based upon alert levels.

Heineman, J.B.; Ragland, W.A.; Mueller, C.J.

1985-01-01

39

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

Code of Federal Regulations, 2010 CFR

...5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered...either fixed or mobile, used to lift and transport a patient in...

2009-04-01

40

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

Code of Federal Regulations, 2013 CFR

...5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered...either fixed or mobile, used to lift and transport a patient in...

2013-04-01

41

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

Code of Federal Regulations, 2010 CFR

...5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered...either fixed or mobile, used to lift and transport a patient in...

2010-04-01

42

DC microgrid based distribution power generation system  

Microsoft Academic Search

This paper describes an autonomous-control method for a DC microgrid system having distribution power generators. This system consists of following five generation and control units; a solar-cell generation unit, a wind-turbine generation unit, a battery energy-storage unit, a flywheel power-leveling unit, and an AC grid-connected power control unit. The proposed control method intended for suppression of circulating current detects only

Y. Ito; Y. Zhongqing; H. Akagi

2004-01-01

43

Magnetic power inverter: AC voltage generation from DC magnetic fields  

NASA Astrophysics Data System (ADS)

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

Ieda, Jun'ichi; Maekawa, Sadamichi

2012-12-01

44

Control and testing system based on LabVIEW for programmable AC power source  

Microsoft Academic Search

The programmable AC power source is the important signal source in the power source measurement filed. It is necessary to ensure precision of the voltage signals that the programmable AC power source outputs. For the sake of confirming precision of the voltage signals, there are lots of testing items for the programmable AC power source. These testing items result in

Fu Wei; Zhu Yan; Fu Junli; Ouyang Puzhong

2011-01-01

45

Multi-electrodes in SAW with square wave ac power  

SciTech Connect

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

Bunker, T.A.

1982-07-01

46

Trends in A.C. Power Conditioning for Telecommunications  

Microsoft Academic Search

This paper describes the current characteristics of power quality and electrical and physical environment important for uninterruptible power conditioning equipment serving emerging telecommunications installations. It relates several new solutions using solid state conversion techniques to serve these needs. Characteristics such as electrical performance, power distribution, power consumption (real and reactive), input current distortion, load compatibility and interaction are explored. Physical

David C. Griffith

1985-01-01

47

Power factor improvement of an AC\\/AC converter by association of PDM control and passive filtering  

Microsoft Academic Search

PDM control and passive filtering are combined to improve, to a significant degree and at lower costs, the power factor of an AC\\/AC power converter consisting of a single-phase diode bridge rectifier and a series inverter without the smoothing filter of the DC voltage. A low-pass filter absorbs the harmonics of the rectifier input current, whereas PDM control, applied to

Abdelhalim Sandali; Pierre Sicard; Ahmed Cheriti

2002-01-01

48

Unloading Performance Analysis of Main Generator in Aeronautic AC Power Supply Based on Ansoft  

Microsoft Academic Search

Equivalent magnet circuit method is adopted in investigating main generator in three-level synchronous generator system of aeronautic AC power supply. With RMxprt software of Ansoft corporation, it establishes geometrical model and computes primary electrical parameters. Furthermore, with Maxwell 2D software, it attains two-dimensional transient model and simulates magnetic spacial distributing, electromagnetic and circuit parameters under unloading. With contrast to actual

Gong Feng; Ma Zhen; Li Jianlei; Zhang Xianjiang

2008-01-01

49

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

50

The interphase power controller: A new concept for managing power flow within AC networks  

Microsoft Academic Search

The paper presents a new concept for controlling the flow of power within AC networks. The application is based on the series connection of impedances between different phases of the two (synchronous) subnetworks to be interconnected, hence its name: the Interphase Power Controller (IPC). The IPC acts as a current source with the following characteristics: the power flow is nearly

J. Brochu; P. Pelletier; F. Beauregard; G. Morin

1994-01-01

51

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

NASA Astrophysics Data System (ADS)

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

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

52

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

Microsoft Academic Search

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

S. C. Peak

1982-01-01

53

Industrial power distribution  

SciTech Connect

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

Sorrells, M.A.

1990-01-01

54

Microgrids [distributed power generation  

Microsoft Academic Search

Environmentally friendly renewable energy technologies such as photovoltaics and clean, efficient, fossil-fuels technologies such as micro-turbines and fuel cells are among new generating systems driving the demand for distributed generation of electricity. If combined heat and power at residential industrial plants or commercial buildings can be achieved the efficiencies can be higher than conventional central generation plants. The smallness of

B. Lasseter

2001-01-01

55

Improved Transistorized AC Motor Controller for Battery Powered Urban Electric Passenger Vehicles.  

National Technical Information Service (NTIS)

The objectives of this program for an improved ac motor controller for battery powered urban electric passenger vehicles were: the design, fabrication, test, evaluation and cost analysis of an engineering model controller for an ac induction motor drive s...

S. C. Peak

1982-01-01

56

A review of three-phase improved power quality AC-DC converters  

Microsoft Academic Search

Three-phase AC-DC converters have been developed to a matured level with improved power quality in terms of power-factor correction, reduced total harmonic distortion at input AC mains, and regulated DC output in buck, boost, buck-boost, multilevel, and multipulse modes with unidirectional and bidirectional power flow. This paper presents an exhaustive review of three-phase improved power quality AC-DC converters (IPQCs) configurations,

Bhim Singh; Brij N. Singh; Ambrish Chandra; Kamal Al-Haddad; Ashish Pandey; Dwarka P. Kothari

2004-01-01

57

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

58

A Low Cost Power Electronic Interface for Small Scale Wind Generators in Single Phase Distributed Power Generation System  

Microsoft Academic Search

This paper presents a low cost power electronic interface for interfacing variable speed small scale wind turbine generators to a single phase distributed generation system. The power electronics architecture employs an AC\\/DC\\/AC topology for converting the variable power input from a permanent magnet wind generator to a constant voltage, constant frequency grid. The inverter is unidirectional, transformer less and is

Chem Nayar; Hooman Dehbonei; Liuchen Chang

2005-01-01

59

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

Microsoft Academic Search

An electric vehicle propulsion system controller which uses an ac induction electric motor as the electrical to mechanical energy conversion unit was designed and developed. The contract program was to design and test an improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery, would provide a complete electric vehicle power train

Latos

1982-01-01

60

DC Voltage Control of the DC Micro-Grid for Super High Quality Electric Power Distribution  

Microsoft Academic Search

``DC Micro-grid'' is a novel power system using dc distribution in order to provide super high quality electric power. The power is distributed through dc distribution line and converted to required ac or dc voltages by converters placed near loads. The load side converters do not need transformers by choosing proper distributed dc voltage (±170V). The dc distribution line is

Hiroaki Kakigano; Yushi Miura; Toshifumi Ise; Ryohei Uchida

2007-01-01

61

Light weight electrostatic generator of ac power for aerospace uses  

NASA Astrophysics Data System (ADS)

It will be shown in this paper that an electrostatic generator is superior to a magnetic generator as far as weight and specific weight is concerned. To compare an electrostatic with a magnetic generator an evaluation of the specific weight of a magnetic generator is presented. The electrostatic generator consists of N+1 rotating circular disks of radius R and thickness d. For vacuum the specific power of the electrostatic engine is 5.15 kW/kg which is better than the value given for the magnetic generator. To prove the principle and the (nonlinear) stabilization of the generator a model has been built. It delivered 1050 V of sinusoidal ac at 350 cycles. Such generators are typical low weight high-frequency high voltage low current generators for uses in the vacuum of cosmic space.

Cap, F. F.

1986-10-01

62

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

Microsoft Academic Search

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

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

1980-01-01

63

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

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

Distributed Power System for Microsatellites.  

National Technical Information Service (NTIS)

The Aerospace Corporation has independently developed a distributed 'Ring Bus' electric power system for Picosatellites. This distributed power system architecture is being implemented on a number of upcoming Picosatellite missions. The first implementati...

E. J. Simburger D. Rumsey D. Hinkley S. Liu P. Carian

2004-01-01

66

Electromagnetic switching transients on AC power systems; theory, simulation, analysis  

SciTech Connect

An urgent need exists to improve the quality of electrical power supplied to consumers who use sensitive equipment such as digital computer or microprocessor-controlled manufacturing facilities. Switching transient studies are normally performed on an analog computer called a Transient Network Analyzer (TNA), or on a digital computer using a program called the Electromagnetic Transient Program (EMTP). The number of TNAs is inadequate to support all the switching transient studies that need to be accomplished. While the availability of EMTP for use on advanced micro-computers has certainly provided the possibility for making switching transient studies more widespread than ever before, the amount of time involved in learning to use EMTP effectively overshadows its utility. In this study, a program called TP Editor is introduced to serve an a file developer for inputs to EMTP. TP Editor is designed to be used exclusively on AC power systems in the evaluation of switching transients. This permits the power system engineer to use raw system data, which he has available, as inputs to TP Editor. This program then transforms the data into a format acceptable by EMTP. The engineer is freed of the drudgery of verifying the consistency of data types for all of the various types of data acceptable by EMTP. A system of cross checks used in TP Editor insures that the data, is in the proper units, and that the best fit of format is used in the data formats for each individual entry into EMTP. Data is accepted by TP Editor in nearly any form that the engineer has available. TP Editor will perform all calculations necessary to transform that data to a usable form by EMTP. The TP Editor generated inputs to EMTP permit the power system engineer to concentrate his efforts on methods of improvement of power quality rather than on data format procedures.

Kee, R.J.

1989-01-01

67

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

68

Analysis and design of a near unity power factor single phase trapezoidal AC power supply  

Microsoft Academic Search

Single phase AC power supplies used for powering optical fiber\\/coax cable are required to generate trapezoidal-shaped waveform. The proposed converter topology has the following main features: (a) a small DC bus capacitor resulting in a DC bus having a very large 120 Hz component; (b) an on-line instantaneous voltage controlled feedforward PWM pattern generator, based on reset integral control technique,

N. Kaushik; P. Jain; G. Joos

1997-01-01

69

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

Microsoft Academic Search

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

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

2004-01-01

70

Evaluation of available transfer capability in AC-DC hybrid power systems using point estimation  

Microsoft Academic Search

In deregulated market, available transfer capability (ATC) is a market signal refers to the capability of a system to transport above already subscribed transmission uses. It can provide significant information for power market participants. This paper deals with the evaluation of ATC for the integration of HVDC link with an AC power system. The computational model of ATC for AC-DC

Junqiang Wei; Gengyin Li; Ming Zhou

2011-01-01

71

Ground Fault and Overcurrent Protection Criteria for Coal Mine AC Distribution Systems.  

National Technical Information Service (NTIS)

Ground fault and overcurrent protection criteria for coal mine ac distribution systems were examined by authorization of the Bureau of Mines. The report begins with a literature review that discusses relaying topics including instrument transformers, grou...

J. A. Kiefer J. L. Kohler

1980-01-01

72

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

73

A new DC-DC converter for fuel cell powered distributed residential power generation systems  

Microsoft Academic Search

Fuel cell powered distributed residential power generation systems are considered attractive because of their various advantages, such as high efficiency, low pollution, and low noise. A DC-DC converter having a high turn ratio transformer is needed in such a system, to boost the low voltage of the fuel cell to a high level, to enable the DC-AC conversion and to

Rahul Sharma; Hongwei Gao

2006-01-01

74

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

Microsoft Academic Search

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

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

2007-01-01

75

The interphase power controller: A new concept for managing power flow within AC networks  

SciTech Connect

The paper presents a new concept for controlling the flow of power within AC networks. The application is based on the series connection of impedances between different phases of the two (synchronous) subnetworks to be interconnected, hence its name: the Interphase Power Controller (IPC). The IPC acts as a current source with the following characteristics: the power flow is nearly constant (within 10%) for a wide range ([+-]25[degree]) of angle between the two subnetworks; there is no significant short-circuit contribution from one network to the other; severe contingencies on one side of the IPC have negligible impact on the voltage of the other side; no harmonics are generated (because there is no control action). Other operating conditions (reduced power, reactive power generation or absorption) are possible by switching impedance components. In all cases, the IPC comprises only conventional elements (transformer, capacitors, reactors, and circuit breakers).

Brochu, J.; Pelletier, P.; Beauregard, F.; Morin, G. (Citeq, Varennes, Quebec (Canada))

1994-04-01

76

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.

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

77

Simulation and control of bus conditioner for a power distribution system of More Electric Aircraft  

Microsoft Academic Search

In a power distributed system of More Electric Aircraft with many loads on the dc or ac bus, there are harmonic and reactive currents when a large load is loaded or unloaded from the bus. The bus conditioner can compensate the harmonic and reactive currents on dc and ac bus in power system. This paper presents a sample of a

Shuanqin Xie; Jianying Gong; Weiguo Liu

2010-01-01

78

Improved SCR AC Motor Controller for Battery Powered Urban Electric Vehicles.  

National Technical Information Service (NTIS)

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...

T. S. Latos

1982-01-01

79

A FACTS Device: Distributed Power-Flow Controller (DPFC)  

Microsoft Academic Search

This paper presents a new component within the flexible ac-transmission system (FACTS) family, called distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC). The DPFC can be considered as a UPFC with an eliminated common dc link. The active power exchange between the shunt and series converters, which is through the common dc link in

Zhihui Yuan; S. W. H. de Haan; J. B. Ferreira; D. Cvoric

2010-01-01

80

Commercial utility frequency AC to high frequency AC soft switching power conversion circuit with non smoothing DC link for IH dual packs heater  

Microsoft Academic Search

In this paper, a novel topology of soft switching PWM high frequency AC power conversion conditioning and processing circuit without DC smoothing capacitor filter link from the voltage grid of utility frequency AC power supply source with 60 Hz-100 V or 60 Hz-200 V is proposed and introduced for innovative consumer induction heating (IH) boiler applications as a hot water

Hisayuki Sugimura; Tarek Ahmed; Mohamed Orabi; Hyun-Woo Lee; Mutsuo Nakaoka

2004-01-01

81

Main Injector power distribution system  

SciTech Connect

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

Cezary Jach and Daniel Wolff

2002-06-03

82

Power management and distribution technology  

Microsoft Academic Search

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

John Ellis Dickman

1993-01-01

83

Development of Software to Improve AC Power Quality on Large Spacecraft.  

National Technical Information Service (NTIS)

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 ...

L. A. Kraft

1991-01-01

84

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

85

Power-law resistivity, magnetic relaxation and ac susceptibility.  

National Technical Information Service (NTIS)

The nonlinear diffusion of magnetic flux into a superconducting sample can be studied by measuring the relaxation of the magnetisation after application of a step field or by measuring the ac susceptibility, (chi)(sub 1) and its third harmonic, (chi)(sub ...

J. Gilchrist C. J. van der Beek

1994-01-01

86

Power management and distribution technology  

NASA Astrophysics Data System (ADS)

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

87

Design on four-quadrant DC\\/AC converter for wind power flow optimization system  

Microsoft Academic Search

A four-quadrant DC\\/AC converter for wind power flow optimization system is designed. Firstly, the basic idea of wind power flow optimization and control is analyzed. Secondly, working principle of the four-quadrant DC\\/AC converter is explained and its linear small signal mathematical model in the rotating reference frame is constructed. Then, based on the model, control unit consisting of active current

Yanlei Zhao; Lei Zhang; Housheng Zhang

2011-01-01

88

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

NASA Astrophysics Data System (ADS)

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

Chunkag, Viboon; Kamnarn, Uthen

89

New techniques in the design of distributed power systems  

NASA Astrophysics Data System (ADS)

Power conversion system design issues are expanding their role in information technology equipment design philosophies. These issues include not only improving power conversion efficiency, but also increased concerns regarding the cost and complexity of the power conversion design techniques utilized to satisfy the host system's total performance requirements. In particular, in computer system (personal computers, workstations, and servers) designs, the power "supplies" are rapidly becoming a limiting factor in meeting overall design objectives. This dissertation addresses the issue of simplifying the architecture of distributed power systems incorporated into computing equipment. In the dissertation's first half, the subject of the design of the distributed power system's front-end converter is investigated from the perspective of simplifying the conversion process while simultaneously improving efficiency. This is initially accomplished by simplifying the second-stage DC/DC converter in the standard two-stage front-end design (PFC followed by DC/DC conversion) through the incorporation of secondary-side control. Unique modifications are then made to two basic topologies (the flyback and boost converter topologies) that enable the two-stage front-end design to be reduced to an isolated PFC conversion stage, resulting in a front-end design that features reduced complexity and higher efficiency. In the dissertation's second half, the overall DC distributed power system design concept is simplified through the elimination of power processing conversion steps--the result being the creation of a high-frequency (HF) AC distributed power system. Design techniques for generating, distributing, and processing HF AC power in this new system are developed and experimentally verified. Also, an experimental comparison between both DC and AC distributed power systems is performed, illustrating in a succinct fashion the merits and limitations of both approaches.

Watson, Robert Goah

90

Effects of Source Voltage Harmonic Distortion on Power Factor Compensation in Triac Controlled AC Chopper Circuits  

Microsoft Academic Search

In recent years, detailed modeling of power electronic devices and their behavior on different system conditions are a great concern of the power industries and customers. One of the widely proliferated such devices is the triac controlled ac choppers. Although these types of devices have important application areas, their poor power factor performance is the main obstacle for the large

M. E. Balci; M. H. Hocaoglu

2005-01-01

91

An experimental switched-reluctance generator based distributed power system  

Microsoft Academic Search

This paper presents an experimental switched-reluctance generator (SRG) based distributed power system with common DC grid and single-phase AC 220\\/110V 60Hz outputs. First, a SRG with suitably designed power converter and control scheme is constructed to generate robust DC 48V output. Then it is boosted to establish a 400V common DC grid by a current-fed push-pull (CFPP) DC\\/DC converter. Well-regulated

Y. C. Chang; C. H. Cheng; L. Y. Lu; C. M. Liaw

2010-01-01

92

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

NASA Astrophysics Data System (ADS)

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

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

93

Zero-Voltage Soft-Switched PWM High-Frequency AC-Link DC-DC Converters Incorporating Saturable Reactor-Assisted Capacitive Lossless Snubber Topology for Distributed Power Supply Systems.  

National Technical Information Service (NTIS)

A new constant frequency soft switching phase shifted mode Pulse Width Modulated (PWM) DC-DC power converter topology suitable for high power applications, which incorporates two phase half bridge high frequency inverter and saturable reactor in series wi...

S. Nagai T. Yamamoto M. Nakaoka S. Hamada

1991-01-01

94

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

95

General reconfiguration methodology for AC radial shipboard power systems  

Microsoft Academic Search

The electric power systems of ships supply energy to sophisticated systems for weapons, communications, navigation and operation. In this new era of the US Navy with goals to reduce manning and increase system survivability, automatic reconfiguration of the electrical network in a shipboard power system is critical for quickly restoring service to a section of the power system to survive

K. L. Butler; N. D. R. Sarma

2000-01-01

96

A new synchronous reluctance generator AC\\/DC buck rectifier as a controllable power supply  

Microsoft Academic Search

This paper sets forth the use of a three-phase synchronous reluctance generator feeding a pulse-width modulation (PWM) based AC\\/DC buck rectifier to produce controllable AC and\\/or DC power. This is made possible by controlling both the modulation magnitude and phase angle of the rectifier. This generating scheme is targeted for application requirements for equipment on airplanes, ships or ground vehicles

Olorunfemi Ojo; Ishwar Bhat

1994-01-01

97

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

NASA Astrophysics Data System (ADS)

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

Peak, S. C.

1982-09-01

98

Study of AC\\/DC power supply system with DGs using parallel processing method  

Microsoft Academic Search

This paper proposes a new AC\\/DC power supply system with DGs using the parallel processing method. The purpose of this system is to supply the power without connecting to the utility gird. The DGs consist of photovoltaic (PV) and wind generators (WG), and the main energy source of this system is the DGs and the UPS battery. When the system

K. Yukita; Y. Shimizu; Y. Goto; M. Yoda; A. Ueda; K. Ichiyanagi; K. Hirose; T. Takeda; T. Ota; Y. Okui; H. Takabayashi

2010-01-01

99

Coordination and Optimization Of HVDC Modulations Using Chaotic Optimization Algorithm in DC\\/AC Power System  

Microsoft Academic Search

A Chaotic Optimization Algorithm (COA) is applied to integrated AC\\/DC hybrid power system in which the multi-infeed DC power transmission system is included, and the research on coordination controls among the HVDC modulations has been investigated in this paper. Chaotic Optimization Algorithms, which have the features of easy implementation, short execution time and robust mechanisms of escaping from local minima,

Zheng Xi-yun; Li Xing-yuan; Wang Yu-hong; Xu Mei-mei; Mu Zi-long; Liu Jian; Wei Wei

2010-01-01

100

AC power standard using a programmable Josephson voltage standard  

Microsoft Academic Search

This paper describes the implementation of a new quantum-based system for the generation of 120 V, 5 A, sinusoidal active and reactive power over the 50 Hz to 400 Hz frequency range. The system accurately relates the spectral amplitudes and phases of the voltage and current waveforms of the generated power to a programmable Josephson voltage standard (PJVS) using a

B. C. Waltrip; B. Gong; T. L. Nelson; Y. Wang; C. J. Burroughs; A. Rufenacht; S. P. Benz; P. D. Dresselhaus

2008-01-01

101

AC Power Standard Using a Programmable Josephson Voltage Standard  

Microsoft Academic Search

This paper describes the implementation of a new quantum-based system for the generation of 120 V RMS, 5 A RMS, sinusoidal, active, and reactive power over the 50 to 400 Hz frequency range. The system accurately relates the spectral amplitudes and phases of the voltage and current waveforms of the generated power to a programmable Josephson voltage standard (PJVS) by

Bryan C. Waltrip; Bo Gong; Thomas L. Nelson; Yicheng Wang; Alain Rüfenacht; Samuel P. Benz; Paul D. Dresselhaus

2009-01-01

102

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

DOEpatents

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

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

1987-07-30

103

System for transmitting low frequency analog signals over AC power lines  

DOEpatents

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

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

1989-01-01

104

Using AC Optimal Power Flow for DG planning and optimisation  

Microsoft Academic Search

While it is difficult to estimate how much distributed generation (DG) capacity will be connected to distribution systems in the coming years, it is certain that increasing penetration levels require robust tools that help assess the capabilities and requirements of the networks in order to produce the best planning strategies. This work presents an overview of some of the uses

Luis F. Ochoa; Gareth P. Harrison

2010-01-01

105

High power GTO AC\\/DC current source converter with minimum switching frequency and maximum power factor  

Microsoft Academic Search

This paper presents a unique PWM switching pattern and a novel power factor control scheme for high power GTO AC\\/DC converters. This switching pattern has a switching frequency of 360 Hz, which is the lowest possible frequency to achieve 5th and 7th harmonic elimination and an adjustable DC output current simultaneously. Using both feedback and feedforward control techniques, the proposed

Y. Xiao; B. Wu; F. DeWinter; R. Sotudeh

1996-01-01

106

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

107

AC-DC converter minimizing induced harmonics in industrial power systems  

SciTech Connect

Conventional ac-dc converters present two important disadvantages: they create harmonic currents and require reactive power. To reduce these drawbacks, a diode rectifier is directly connected in series with a chopper controlled by pulsewidth modulation. Both are preceded by a series inductance (added to the equivalent one of the power system) and a shunt capacitor. This study is applied to single-phase powerful electric locomotives. Equivalent three-phase systems are not so interesting.

Destobbeleer, E.; Seguier, G.; Castelain, A.

1987-10-01

108

Ground fault and overcurrent protection criteria for coal mine AC distribution systems. Open file report August 1979-October 1980  

SciTech Connect

Ground fault and overcurrent protection criteria for coal mine ac distribution systems were examined by authorization of the Bureau of Mines. The report begins with a literature review that discusses relaying topics including instrument transformers, ground fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter discusses relay system maintenance and introduces a unique test set that is used to test the performance of relaying systems in coal mines.

Kiefer, J.A.; Kohler, J.L.

1980-10-31

109

DC Voltage Control of the DC Micro-Grid for Super High Quality Electric Power Distribution  

NASA Astrophysics Data System (ADS)

“DC Micro-grid” is a novel power system using dc distribution in order to provide super high quality electric power. The power is distributed through dc distribution line and converted to required ac or dc voltages by converters placed near loads. The load side converters do not need transformers by choosing proper distributed dc voltage (±170V). The dc distribution line is composed of 3 power lines: +170V line, neutral line and -170V line. The voltages of ±170V have to be balanced to supply high quality power. In this paper, a voltage balancing control method for dc distribution is proposed and studied. Computer simulation results demonstrated that dc micro-grid was able to supply both ac and dc power to loads simultaneously and stably by 3-wire dc distribution and load side converters.

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

110

Power Law Distribution in Education  

Microsoft Academic Search

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

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

2003-01-01

111

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

112

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

SciTech Connect

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

Peak, S.C.

1982-09-01

113

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

SciTech Connect

An electric vehicle propulsion system controller which uses an ac induction electric motor as the electrical to mechanical energy conversion unit was designed and developed. The contract program was to design and test an improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery, would provide a complete electric vehicle power train with the exception of the mechanical transmission and drive wheels. 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 1590kg (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. With the aid of a computer simulation, the vehicle acceleration, top speed, and gradeability requirements were translated into electric motor torque and shaft power requirements.

Latos, T.S.

1982-12-01

114

Control of parallel connected inverters in standalone AC supply systems  

Microsoft Academic Search

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

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

1993-01-01

115

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

116

Research and development of super-conductive cable and AC power equipment  

NASA Astrophysics Data System (ADS)

Super-conducting AC power equipment project started as a national project in 2000 fiscal year by METI and NEDO. This project is to research and develop the basic technology of super-conductive cable (high temperature super-conductive cable, HTS-cable), fault current limiter (FCL) and transformer. Main subjects are to study the 3 kA Super-conducive conductor, cooling technology of 500 m HTS-cable, manufacturing technology of 66 kV/1 kA class SN type of FCL, high voltage technology of AC magnet and pulse magnet, and power system analysis of super-conductive cable and AC equipments. The paper describes the background of this project, target of each research subject, schedule of research and development, and major results of research activity in 2001.

Ueda, K.; Ozawa, Y.; Wachi, Y.; Kikuchi, A.; Nakatsuka, T.; Iwadate, K.

2002-10-01

117

A high frequency link direct dc-ac converter for residential fuel cell power systems  

Microsoft Academic Search

This paper describes a boost converter cascaded high frequency link direct dc-ac converter suitable for fuel cell power sources. A new multi-loop control for a boost converter to reduce the low frequency input current harmonics drawn from the fuel cell is proposed. A new PWM technique for the cycloconverter at the secondary to reject the low order harmonics in the

Yu Jin Song; Prasad N. Enjeti

2004-01-01

118

Analysis of power losses in AC\\/DC-converter for electric vehicle drive  

Microsoft Academic Search

In this paper the power losses of an AC\\/DC- converter for an electric vehicle drive are analyzed. A validated model which calculates the losses analytically based on forward parameters and switching losses maps is used to design two converters, one for a standard machine and another for an energy efficiency optimized machine. With this a losses reduction of 25% can

Klaus Muehlbauer; Fabian Bachl; Dieter Gerling

2011-01-01

119

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

Microsoft Academic Search

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

Qing Chen

1998-01-01

120

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2010 CFR

...AC-powered adjustable hospital bed is a device intended for medical purposes that consists of a bed with a built-in electric motor and remote controls that...height and surface contour of the bed. The device includes movable...

2009-04-01

121

21 CFR 880.5100 - AC-powered adjustable hospital bed.  

Code of Federal Regulations, 2010 CFR

...AC-powered adjustable hospital bed is a device intended for medical purposes that consists of a bed with a built-in electric motor and remote controls that...height and surface contour of the bed. The device includes movable...

2010-04-01

122

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

SciTech Connect

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

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

1997-03-01

123

Classification and Technical Review of DC-AC Inverters for Use in Photovoltaic Power Systems.  

National Technical Information Service (NTIS)

A classification system is presented for stand-alone and utility-interactive dc-to-ac inverters used in photovoltaic systems in the 1-to-100-kVA power range. Additional inverter topologies, noted during the classification process, are introduced. To provi...

E. E. Landsman

1979-01-01

124

Induced voltages on fence wires and pipe lines by AC power transmission lines  

Microsoft Academic Search

A method is developed for calculating the induced voltages on fence wires and pipelines underneath AC power transmission lines. The method is based on the charge simulation techniques and takes into account disturbances of the electric field and potential due to the presence of the fence wire or pipeline underneath the line. The calculated and previously measured induced voltages on

M. M. Abdel-Salam; A. M. Al-Shehri

1992-01-01

125

Induced voltages on fence wires and pipelines by AC power transmission lines  

Microsoft Academic Search

A method is developed for calculating the induced voltages on fence wires\\/pipelines underneath AC power transmission lines. The method is based on the charge simulation technique and takes into account the disturbances of the electric field and potential due to the presence of the fence wire\\/pipeline underneath the line. The calculated values of the induced voltage on fence wires are

M. Abdel-Salam; A. Al-Shehri

2009-01-01

126

Control of doubly-fed induction generators for distributed wind power generation  

Microsoft Academic Search

The wind power generation technology has evolved significantly in the past few years with the demand for distributed, renewable energy growing. The doubly-fed induction generator (DFIG) is one of the most attractive solutions among many energy conversion devices for wind energy. The doubly-fed induction generator with a back-to-back four-quadrant ac-dc-ac power converter between the rotor side and the grid side

Xunwei Yu; Zhenhua Jiang; Yu Zhang

2008-01-01

127

Advanced simulation concept for the power train of an AC locomotive and its verification  

Microsoft Academic Search

Recent AC railway traction vehicles contain two main power electronic components in the power train, the four-quadrant converter and the three-phase machine-side inverter. They are joined by a common DC-link capacitor and - often - a resonant circuit tuned to twice the supply frequency. Converter and inverter are mainly controlled separately. The overall performance of the traction vehicle can be

V. Staudt; C. Heising; A. Steimel

2007-01-01

128

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

PubMed

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

Liu, Jhao-Yan; Tang, Kea-Tiong

2013-07-01

129

Description of a 20 kilohertz power distribution system  

NASA Astrophysics Data System (ADS)

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

Hansen, I. G.

130

An unity high power factor power supply rectifier using a PWM AC\\/DC full bridge soft-switching  

Microsoft Academic Search

This paper proposes an improvement of an isolated unity-power-factor rectifier AC\\/DC PWM based on a PWM full bridge converter using a commutation cell. This converter operates using soft switching technique. It presents high power factor, full control of the output dc voltage and high-frequency line filter inductor and insulation transformer. It is based in an auxiliary voltage source that feeds

C. A. Gallo; J. A. Correa Pinto; L. C. de Freitas; V. J. Farias; E. A. A. Coelho

2002-01-01

131

Simulation of urban water distribution system for distributed power generation  

Microsoft Academic Search

Distributed power generation is an emerging technique for satisfying the growing power demand due to the continuous population growth in the urban areas. Successful siting of distributed power generator needs to consider the spatial demand for power and the supporting infrastructures. One of the important supporting infrastructures is water supply system. This paper describes a framework that integrates urban growth

Preethi Prakash Rao; Ke Li

2011-01-01

132

Voltage control availability of distributed generators in power distribution system  

Microsoft Academic Search

In spite of many profitable or advantageous natures of distributed generators (DGs), for power systems, such badly behaved natures of DGs as (1) unstable power output, (2) voltage problem, (3)harmonics, (4)reverse power flow, etc. also exist. Therefore, it has been always emphasized that the unfavorable effects should not exist when distributed generators are connected to the power system. However, in

K. Nara; S. Ishizu; Y. Mishima

2005-01-01

133

Current distribution and ac loss for a superconducting rectangular strip with in-phase alternating current and applied field  

Microsoft Academic Search

The case of ac transport at in-phase alternating applied magnetic fields for a superconducting rectangular strip with finite thickness is investigated. The applied magnetic field is considered to be perpendicular to the current flow. We present numerical calculations assuming the critical-state model of the current distribution and ac loss for various values of aspect ratio, transport current and applied field

E. Pardo; F. Gömöry; J. Souc; J. M. Ceballos

2007-01-01

134

Design and demonstration of an on-chip AC power source for adiabatic quantum-flux-parametron logic  

NASA Astrophysics Data System (ADS)

Adiabatic quantum-flux-parametron (AQFP) logic is a promising technology for use in future high-end computers because its bit energy can be potentially reduced to the order of thermal energy. AQFP gates are driven by an AC bias current, which changes their potential energy adiabatically. In the present paper, we propose an on-chip AC power source, which is composed of a Josephson relaxation oscillator and a superconducting resonator, to drive the AQFP gates. We designed and implemented the AC power source using a Nb Josephson integrated circuit process. We confirmed that the AC power source can generate a 4.4 GHz sinusoidal current from a DC bias current and that the output amplitude of the AC power source can be controlled by varying the DC bias current.

Mukaiyama, Takashi; Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki

2013-03-01

135

Evaluation of Uncertainty in AC Power Calculation with Asynchronously Sampled Data  

NASA Astrophysics Data System (ADS)

This article presents a comparison of several standard based methods for determination of the effective and the apparent AC power from sampled voltage and current signals. The comparison is based on the accuracy achieved in three different measurement scenarios, which is evaluated by means of Monte-Carlo-simulations. The comparison shows that the accuracy of the power estimation from asynchronously sampled data can be as good as the power estimation from synchronously sampled data. This allows for a reduction of the effort for synchronization between voltage and current channels while the overall performance remains equal.

Lindenthaler, D.; Zangl, H.

2013-06-01

136

New Design Parameters for Computer Power Distribution  

Microsoft Academic Search

Changing technology in the design of new computer power supplies has prompted a reexamination of how electrical power is distributed in a computer center. Proper electrical isolation between computer loads is becoming more important in total center design. This paper is a discussion of the electrical characteristics of a total computer power distribution system. Current harmonics generated by newer power

Bradford P. Roberts

1979-01-01

137

A High-Efficiency AC-to-DC Adaptor with a Low Standby Power Consumption  

Microsoft Academic Search

A two-stage burst mode control scheme for a high-efficiency AC-to-DC adaptor is proposed in this paper. The boost power factor corrector (PFC) is operated at the discontinuous conduction mode (DCM). The half-bridge series-parallel resonant converter (HB-SPRC) is adopted as the DC\\/DC topology. An upper limit for the output voltage is set to turn off both two control IC's at either

Yu-Kang Lo; Shang-Chin Yen; Jin-Yuan Lin

2006-01-01

138

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

Microsoft Academic Search

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

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

2011-01-01

139

A prepositioned highly precision voltage regulator of AC regulated power supply based on single-chip micro-computer  

Microsoft Academic Search

This paper presents a novel prepositioned highly precision voltage regulator method based on single-chip micro-computer, uses a timing AC Servo Power Supply to make use of servo motor controlling Autotransformer, explains the working principle of the circuit, gives flowchart software, hardware block diagram and circuit schematic diagram. The realization of intelligent prepositioned highly precision voltage regulator and timing AC servo

Liu Zhen-ya; Chen Rong; Jiang Yan-hu; Liu Xiao-wei; Zhu Li-xing

2010-01-01

140

A single-phase three-level pulsewidth modulation AC\\/DC converter with the function of power factor corrector and active power filter  

Microsoft Academic Search

A single-phase three-level pulsewidth modulation (PWM) AC\\/DC converter with the function of power factor corrector and active power filter is proposed to reduce harmonic currents flowing into the power system and to draw a nearly sinusoidal current with unity power factor. The circuit topology of the adopted three-level PWM AC\\/DC converter is based on a conventional two-level full-bridge rectifier and

Bor-Ren Lin

2001-01-01

141

Electric power distribution and load transfer system  

SciTech Connect

This patent describes a power distribution system. It comprises at least two switch means for controlling the application of power from a power source to a power output; at least two current means for preventing reverse power flow through respective ones of switch means; and processing means for providing control signals to operate the switch means, effective to switch respective ones of the power sources between on and off states with respect to the power output.

Bradford, M.P.; Parkinson, G.W.; Grant, R.M.

1989-10-10

142

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

NASA Astrophysics Data System (ADS)

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

Karshenas, Hamid Reza

143

Surge Protection in Low-Voltage AC Power Circuits: An Anthology Part 4. Propagation and Coupling of Surges.  

National Technical Information Service (NTIS)

The papers included in this part of the Anthology provide basic information on the propagation of surges in low-voltage AC power circuits. The subject was approached by a combination of experiments and theoretical considerations. One important distinction...

F. D. Martzloff

2002-01-01

144

Minimum Loss Configuration of Power Distribution System  

Microsoft Academic Search

This paper presents a new method for minimum loss reconfiguration for radial power distribution system, in which the choice of the switches to be opened \\/ closed is based on the calculation of voltage at the buses, real and reactive power flowing through lines, real power losses and voltage deviation, using distribution load flow (DLF) program. In the process of

Jaswanti; T. Thakur

2006-01-01

145

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

Microsoft Academic Search

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

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

2007-01-01

146

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

Microsoft Academic Search

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

U. Leeton; T. Ratniyomchai; T. Kulworawanichpong

2010-01-01

147

Power scalable processing using distributed arithmetic  

Microsoft Academic Search

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

Rajeevan Amirtharajah; Thucydides Xanthopoulos; Anantha Chandrakasan

1999-01-01

148

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

149

HF power combining and distributing devices  

Microsoft Academic Search

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

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

1980-01-01

150

Coarse-grained distributed optimal power flow  

Microsoft Academic Search

We present an approach to parallelizing optimal power flow (OPF) that is suitable for coarse-grained distributed implementation and is applicable to very large interconnected power systems. We demonstrate the approach on several medium size systems, including IEEE Test Systems and parts of the ERCOT system. Our simulations demonstrate the feasibility of distributed implementation of OPF. Rough estimates are made of

Balho H. Kim; Ross Baldick

1997-01-01

151

Optimum Evaluation of Reactive Power Requirements in Power Distribution Systems  

Microsoft Academic Search

This paper presents three methodologies for determining optimum locations and magnitudes of reactive power compensation in power distribution systems. Method I and Method II are suitable for complex distribution systems with a combination of both radial and ring-main feeders and having different voltage levels. Method III is suitable for low-tension single voltage level radial feeders. Method I is based on

D. Thukaram; K. Parthasarathy; B. S. Ramakrishna IYENGAR

1985-01-01

152

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.

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

2002-01-01

153

A current-fed HF link direct DC\\/AC converter with active harmonic filter for fuel cell power systems  

Microsoft Academic Search

This paper describes a current-fed high frequency (HF) link direct DC\\/AC converter suitable for fuel cell power source. The proposed current-fed HF link direct DC\\/AC converter consists of a current-fed full-bridge inverter with an active harmonic filter, a HF link transformer, and a simple cycloconverter. The high frequency full-bridge inverter at the primary generates sinusoidally PWM modulated current pulses with

Yu Jin Song; Se-Kyo Chung; Prasad N. Enjeti

2004-01-01

154

Parallelising calculations in electric power distribution networks  

Microsoft Academic Search

CART (Computer Aided Reticulation of Townships) is a software package used for the design of radial, electrical power distribution networks. Having many transformers and large numbers of consumers in the distribution network significantly increases computation time. A distributed, service-based platform is being developed, with parallelisation functionality for CART as the flagship service. The system will be used to parallelise CART's

Y. Neumann; B. Dwolatzky

2002-01-01

155

Linear averaged and sampled data models for large signal control of high power factor AC-DC converters  

Microsoft Academic Search

It is shown that the large signal behavior of a popular family of high power factor AC-to-DC power conditioners can be analyzed via linear models, by using squared output voltage as the state variable. The state equation for a general (constant power plus resistive) load is obtained by a simple dynamic power balance. Time-invariant or periodically varying controllers acting at

K. Mahabir; G. Verghese; J. Thottuvelil; A. Heyman

1990-01-01

156

Advanced solution for on-site diagnosis of distribution power cables  

Microsoft Academic Search

This paper describes important aspects of PD diagnostics of distribution power cables. PD parameter were discussed under consideration of attenuation and dispersive effects of cable characteristics. Field experiences with PD diagnosis on PILC and XLPE cables by energizing with Damped AC Voltage demonstrate relevant demands and the effective outcome for asset management decision support. The main difficulty is to evaluate

Frank Petzold; Edward Gulski; Paul P. Seitz; Ben Quak; Hubert Schlapp

2008-01-01

157

Power scalable processing using distributed arithmetic  

Microsoft Academic Search

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

Rajeevan Amirtharajah; Thucydides Xanthopoulos; Anantha Chandrakasan

1999-01-01

158

Wind power distribution over the ocean  

NASA Astrophysics Data System (ADS)

Probability distribution and power density of wind speed over global oceans are computed from eight years of QuikSCAT measurements. They describe the variation and higher moments of wind speed that are critical in relating the non-linear effects of wind on electric power generation capability, shipping hazard, and air-sea exchanges in heat, water, and greenhouse gases. The power density distribution confirms our general knowledge of atmospheric circulation related to mid-latitude storm tracks, trade winds, and monsoons. It also reveals regions of high wind power associated with flow distortion by land, wind channeled by land topography, and buoyancy effect on turbulent stress driven by ocean fronts.

Liu, W. Timothy; Tang, Wenqing; Xie, Xiaosu

2008-07-01

159

PADD: Power Aware Domain Distribution  

Microsoft Academic Search

Modern data centers usually have computing resources sized to handle expected peak demand, but average demand is generally much lower than peak. This means that the systems in the data center usually operate at very low utilization rates. Past techniques have exploited this fact to achieve significant power savings, but they generally focus on centrally managed, throughput-oriented systems that process

Min Yeol Lim; Freeman L. Rawson III; Tyler K. Bletsch; Vincent W. Freeh

2009-01-01

160

Power Law Distribution in Education  

Microsoft Academic Search

We studied the statistical distribution of candidate's performance which is measured through their marks in university entrance examination (Vestibular) of UNESP (Universidade Estadual Paulista) for years 1998, 1999, and 2000. All students are divided in three groups: Physical, Biological and Humanities. We paid special attention to the examination of Portuguese language which is common for all and examinations for the

Hari M. Gupta; José R. Campanha; Fernando D. Prado

2000-01-01

161

Ground fault and overcurrent protection criteria for coal mine AC distribution systems. Open file report August 1979October 1980  

Microsoft Academic Search

Ground fault and overcurrent protection criteria for coal mine ac distribution systems were examined by authorization of the Bureau of Mines. The report begins with a literature review that discusses relaying topics including instrument transformers, ground fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground fault relaying provides recommendations for maximum and minimum pickup levels

J. A. Kiefer; J. L. Kohler

1980-01-01

162

Improved SCR AC-Motor Controller for Battery-Powered Urban Electric Vehicles.  

National Technical Information Service (NTIS)

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

T. S. Latos

1982-01-01

163

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

SciTech Connect

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

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

2010-02-22

164

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

NASA Astrophysics Data System (ADS)

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.

1990-02-01

165

Vibration Monitoring of Power Distribution Poles.  

National Technical Information Service (NTIS)

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 su...

C. Scott G. Heath J. Svoboda

2006-01-01

166

Voltage Synthesis Using Dual Virtual Quadrature Sources—A New Concept in AC Power Conversion  

Microsoft Academic Search

Controlling an ac voltage often involves changing the amplitude, phase, and\\/or harmonic content of the voltage. This can require the addition of voltage at or around the zero crossing of the available ac voltage. Synthesis of this additional voltage normally requires an ac or dc source (or energy storage element) from which the desired voltage can be synthesized using pulsewidth

Deepak M. Divan; J. Sastry

2008-01-01

167

Voltage Synthesis Using Dual Virtual Quadrature Sources - A New Concept in AC Power Conversion  

Microsoft Academic Search

Dynamic control of amplitude and phase of AC line voltage will allow node voltage and branch current in meshed systems. This has traditionally required the use of inverters with energy storage, and\\/or AC\\/AC converters with multiple phases. This paper presents a novel concept wherein dual virtual quadrature sources are used to synthesize both a direct and quadrature component of the

Deepak Divan; Jyoti Sastry

2007-01-01

168

Proposal of a AC\\/DC converter with unitary power factor for a thermal plasma torch system  

Microsoft Academic Search

This paper describes the project development and the construction of a 50 kW AC\\/DC PWM power supply with power factor correction for use with plasma inertization plant. The main power circuitry is built on a industrial IGBT's three-phase bridge rectifier module configured in a boost regulator topology and supplies by means of an electronic chopper, the 850 Vdc link. To

M. V. M. de Aguiar; P. S. Luciano; A. O. Salazar; J.-P. Dubut

2009-01-01

169

Power laws, Pareto distributions and Zipf's law  

NASA Astrophysics Data System (ADS)

When the probability of measuring a particular value of some quantity varies inversely as a power of that value, the quantity is said to follow a power law, also known variously as Zipf's law or the Pareto distribution. Power laws appear widely in physics, biology, earth and planetary sciences, economics and finance, computer science, demography and the social sciences. For instance, the distributions of the sizes of cities, earthquakes, forest fires, solar flares, moon craters and people's personal fortunes all appear to follow power laws. The origin of power-law behaviour has been a topic of debate in the scientific community for more than a century. Here we review some of the empirical evidence for the existence of power-law forms and the theories proposed to explain them.

Newman, Mej

2005-09-01

170

Biodeterioration of asbestos cement (AC) pipe in drinking water distribution systems  

Microsoft Academic Search

Various types of microorganisms have been found to inhabit the inner surfaces of asbestos cement (AC) pipe and their activities can cause significant structural damage. They cause a patina to form on the inside surface of AC pipes as a distinctively continuous coating, commonly 2–5 mm in thickness and generally pigmented as yellow, orange, brown or black depending on the metallic

Dunling Wang; Roy Cullimore; Yafei Hu; Rudaba Chowdhury

2011-01-01

171

A Distributed Monitoring System For Power Quality  

Microsoft Academic Search

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

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

172

f-? Power Spectrum and Stable Distribution  

NASA Astrophysics Data System (ADS)

The fractional integral of white noise produces a fractal fluctuation with a f-? 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 ?. This result may give a new insight to the basic study of experimentally observed fractal noises, especially those in turbulence.

Takayasu, Hideki

1987-04-01

173

Annual Power Distribution Conference, 33rd, 1980  

SciTech Connect

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

Not Available

1980-01-01

174

14 CFR 23.1310 - Power source capacity and distribution.  

Code of Federal Regulations, 2013 CFR

...Power source capacity and distribution. 23.1310 Section 23...AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC...Power source capacity and distribution. (a) Each installation...one power supply system, distribution system, or other...

2013-01-01

175

A multikilowatt polyphase ac\\/dc converter with reversible power flow and without passive low frequency filters  

Microsoft Academic Search

An efficient ac to dc converter with reversible power flow, which embodies an active, low frequency filter, is presented. A non-dissipatively controlled, nonlinear resonant oscillator is used to extract electric energy directly from the phase pairs of the polyphase supply line and to generate a mixed amplitude and frequency modulated carrier. The demodulated carrier and the therefrom resulting 20 kHz

F. C. Schwarz; W. L. Moize de Chateleux

1979-01-01

176

Surge Protection in Low-Voltage AC Power Circuits: An Anthology. Part 8. Coordination of Cascaded Surge-Protective Devices.  

National Technical Information Service (NTIS)

The papers included in this part of the Anthology provide basic and tutorial information on the coordination of the so-called 'Cascaded SPDs' in the context of low-voltage AC power circuits. As presented in this part of the anthology, the subject was appr...

F. D. Martzloff

2002-01-01

177

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

178

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

179

Power distribution engineering: Fundamentals and applications  

SciTech Connect

Covering virtually all areas of distribution engineering, this thoroughly up-to-date reference examines the unique behavior of utilities and provides the practical knowledge necessary to solve real-world distribution problems. Simplifying seemingly difficult concepts and calculations, Power Distribution Engineering addresses topics typically associated with power quality such as sags, swells, harmonics, electromagnetic fields, and stray voltage; describes different types of system designs and grounding as well as values for voltage, line lengths, and load and fault levels; details the loading, construction, and rating of various transformers; presents methods to maximize the effectiveness of capacitor placement; explains overcurrent and overvoltage protection of distribution systems; evaluates utilities using economic techniques that incorporate ideas such as present worth, carrying charge, cost of losses, operating costs, and customer satisfaction. Furnishing over 425 helpful equations, tables, drawings, and photographs, Power Distribution Engineering is an invaluable resource for electrical and electronics, utility distribution, power systems, control, protection, and relaying engineers, as well as graduate students in these disciplines.

Burke, J.J.

1994-01-01

180

A High-Efficiency AC-to-DC Adaptor With a Low Standby Power Consumption  

Microsoft Academic Search

A two-stage burst mode control scheme for an AC-to-DC adaptor is proposed in this paper. An upper limit for the output voltage is set to turn off both AC\\/DC and DC\\/DC controllers at no load. The burst-mode operations of the DC\\/DC and the AC\\/DC converters are in turn enabled when reaching the lower limit of the output voltage. Load analysis

Yu-Kang Lo; Shang-Chin Yen; Chung-Yi Lin

2008-01-01

181

Power loss analysis and measurement of a high efficiency DC-DC converter for EV traction AC drives  

Microsoft Academic Search

Previous works have shown the power design effectiveness of novel H-bridge-based DC-DC boost conversion structure, as well as the feasibility of real-time DC-link voltage adaptation to inverter load, in battery-supplied AC motor drives. In this paper a novel test bench has been developed, suitable for power loss measurements in high-efficiency bi-directional DC-DC converters. In order to allow for quasi-direct measurement

A. Fratta; P. Guglielmi; G. M. Pellegrino; F. Villata

2000-01-01

182

Generation of VLF Mode Instability by Generalized Distribution Function in the Presence of Parallel AC Electric Field in Uranus  

NASA Astrophysics Data System (ADS)

VLF (very low frequency) mode instability with parallel AC electric field was studied for generalized loss-cone distribution with an index j, which is reducible to bi-Maxwellian, loss-cone and delta function for j = 0,1 and ?. The particle trajectories and dispersion relation are obtained through a kinetic approach and method of characteristic solutions. The calculations are compared with the observations of low frequency waves of Voyager 2. The growth rate of plasma parameters suited to magnetosphere of Uranus is obtained. It is inferred that the magnitude as well as frequency of AC (alternating current) field increases the growth rate and widen the band width significantly. In addition to temperature anisotropy, particles in plasma having generalized loss-cone distribution provide an additional source of energy.

S. Pandey, R.; Singh, M.; Pramod, Kumar; M. Singh, K.; S., Kumar

2010-08-01

183

Body fat distribution in women with familial partial lipodystrophy caused by mutation in the lamin A/C gene.  

PubMed

Familial partial lipodystrophy (FPLD), Dunnigan variety, is an autosomal dominant disorder caused due to missense mutations in the lamin A/C (LMNA) gene encoding nuclear lamina proteins. Patients with FPLD are predisposed to metabolic complications of insulin resistance such as diabetes. We sought to evaluate and compare body fat distribution with dual-emission X-ray absorptiometry in women with and without FPLD and identify densitometric, clinical and metabolic features. PMID:22276265

Monteiro, Luciana Z; Foss-Freitas, Maria C; Júnior Montenegro, Renan M; Foss, Milton C

2012-01-01

184

Body fat distribution in women with familial partial lipodystrophy caused by mutation in the lamin A/C gene  

PubMed Central

Familial partial lipodystrophy (FPLD), Dunnigan variety, is an autosomal dominant disorder caused due to missense mutations in the lamin A/C (LMNA) gene encoding nuclear lamina proteins. Patients with FPLD are predisposed to metabolic complications of insulin resistance such as diabetes. We sought to evaluate and compare body fat distribution with dual-emission X-ray absorptiometry in women with and without FPLD and identify densitometric, clinical and metabolic features.

Monteiro, Luciana Z.; Foss-Freitas, Maria C.; Junior Montenegro, Renan M.; Foss, Milton C.

2012-01-01

185

The system for testing electrical performance of power generating sets based on technique of AC sampling  

Microsoft Academic Search

A multilevel distributed system for testing electrical performance of power generating sets based on CAN bus is presented. Sampling and control for electrical parameters are realized utilizing Digital Signal Processor (DSP) and sixteen-bit Microcontroller Unit (MCU) that M16C\\/6N of renesas, an intelligent load based on the MCU of AT89S52 is designed, of which value can change automatically according to the

Lu Wang; Wusong Wen

2010-01-01

186

Hum Noise from AC Transmission Lines (II). Random Walk Model on Space Distribution.  

National Technical Information Service (NTIS)

To evaluate the Hum noise generated from the AC transmission lines during the rain, the spatially statistic properties of Hum noise level were clarified by means of Random Walk theory. On the lateral profile rectangular to the transmission line route, the...

K. Tanabe

1988-01-01

187

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

SciTech Connect

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

Kern, G.

1999-04-01

188

Improved Transistorized AC Motor Controller for Battery Powered Urban Electric Passenger Vehicles.  

National Technical Information Service (NTIS)

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 requirem...

S. C. Peak

1982-01-01

189

Fish Method: Interaction between AC-Machines and Switching Power Converters.  

National Technical Information Service (NTIS)

When studying the complex interaction between AC-machines and converters, proper simulation models are necessary. This thesis is devoted to a new viewpoint on this complex matter: the Fish Method. Based on a seemingly reckless simplification of the machin...

A. Veltman

1994-01-01

190

Harmonic analysis of multi-phase electric-power distribution systems  

Microsoft Academic Search

This study presents a computer program as a tool for the harmonic analysis of multi-phase electric power distribution systems. In the program, the source of harmonics can be any number of multi-phase harmonic currents and\\/or voltages, or up to 10 three-phase converts. Frequency-dependent models of ac network elements are assembled into a sparse admittance matrix. Then, sparsity techniques are employed

Hosseini

1988-01-01

191

Intelligent distributed control for nuclear power plants  

SciTech Connect

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 appendices provide detailed information presented at conference meetings. These are two primary goals of this research. The first is to combine diagnostics and control to achieve a highly automated power plant as described by M.A. Schultz, a project consultant during the first year of the project. This philosophy, as presented in the first annual technical progress report, is to improve public perception of the safety of nuclear power plants by incorporating a high degree automation where greatly simplified operator control console minimizes the possibility of human error in power plant operations. A hierarchically distributed control system with automated responses to plant upset conditions is the focus of our research to achieve this goal. The second goal is to apply this research to develop a prototype demonstration on an actual power plant system, the EBR-II steam plant.

Klevans, E.H.; Edwards, R.M.; Ray, A.; Lee, K.Y.; Garcia, H.E.: Chavez, C.M.; Turso, J.A.; BenAbdennour, A.

1991-01-01

192

A 6.8-W purely-resistive AC light-emitting diode driver circuit with 95% power factor  

Microsoft Academic Search

A light-emitting diode (LED) driver circuit that can operate off of an AC power supply without any reactive elements is described. The proposed circuit consists of resistive components and switches only, making it suitable for a single-chip integrated-circuit (IC) driver solution to realize a low-cost LED replacement for incandescent light bulbs. The driver circuit employs multiple strings of LEDs and

Eunchul Kang; Jaeha Kim; Dohwan Oh; Dongjin Min

2011-01-01

193

A Multikilowatt Polyphase AC\\/DC Converter with Reversible Power Flow and without Passive Low-Frequency Filters  

Microsoft Academic Search

An efficient ac-to-dc converter with reversible power flow, which embodies an active, low-frequency filter, is presented. A nondissipatively controlled, nonlinear resonant oscillator is used to extract electric energy directly from the phase pairs of the polyphase supply line and to generate a mixed amplitude-and frequency-modulated carrier. The demodulated carrier and the resulting 20-kHz pulse train produces, after being processed by

Francisc C. Schwarz; Willem L. F. H. A. Moize De Chateleux

1981-01-01

194

Development and Implementation of Air & Coal On-line Monitoring System Based on AC Induction for Power Plant Boiler  

Microsoft Academic Search

Pulverized coal concentration and velocity of primary air pipe are two important parameters for direct-fired pulverized system, because they influence much on the economics and safety of boiler. This paper mainly introduces a kind of air & coal on-line monitoring system for power plant boiler. The new system makes the use of international advanced technique of AC charge-couple and digital

Xue Zhaomei; Jin Xiaoyang

2010-01-01

195

Increased in output power from fuel cell used metal bipolar plate coated with aC film  

Microsoft Academic Search

An amorphous carbon (a-C) film was coated on the bipolar plate of a fuel cell. This bipolar plate has a low contact resistance between its surface and the membrane electrode assay (MEA) which causes the inner resistance in the fuel cell to be decreased. Therefore, the output power of the fuel cell was increased from 1.3 W to 1.8 W as a

Yoshiyuki Show; Masanori Miki; Taichi Nakamura

2007-01-01

196

Single-switch flyback power-factor-corrected AC\\/DC converter with loosely regulated intermediate storage capacitor voltage  

Microsoft Academic Search

Single-stage power-factor-corrected AC\\/DC converters (SSPFC) usually bear high voltage stress on the intermediate storage capacitor due to the lack of control of this voltage. The storage capacitor voltage varies largely with line voltage and load current and is usually higher than the peak line voltage. This paper presents a new single-switch SSPFC based on flyback topology for which the storage

Dylan Dah-chuan Lu; David Ki-wai Cheng; Yim-shu Lee

2003-01-01

197

A novel single stage step up\\/down AC\\/DC converter for small BLDC wind power generators  

Microsoft Academic Search

In this paper, a novel single stage step up\\/down AC\\/DC converter is proposed for small wind power BLDC generators. Basically, the proposed converter is derived by integrating a brushless DC generator (BLDCG), a full diode bridge, and a C'uk DC to DC converter to achieve same robustness as a traditional diode rectifier but without incurring large torque ripple trouble. Also,

Ching-Tsai Pan; Ting-Yu Chang; Emily Fang

2011-01-01

198

Angular distribution of electrons from powerful accelerators  

NASA Astrophysics Data System (ADS)

A technique for measuring the angular distribution of electrons escaping from the center of the window of the IGUR-3 and ÉMIR-M powerful accelerators (designed at the All-Russia Institute of Technical Physics, Russian Federal Nuclear Center) into ambient air is presented, and measurement data are reported. The number of electrons is measured with cable detectors (the solid angle of the collimator of the detector is ?0.01 sr). The measurements are made in three azimuthal directions in 120° intervals in the polar angle range 0 22°. The angular distributions of the electrons coming out of the accelerators are represented in the form of B splines.

Stepovik, A. P.; Lartsev, V. D.; Blinov, V. S.

2007-07-01

199

Gibbsian Theory of Power-Law Distributions  

SciTech Connect

It is shown that power-law phase space distributions describe marginally stable Gibbsian equilibria far from thermal equilibrium, which are expected to occur in collisionless plasmas containing fully developed quasistationary turbulence. Gibbsian theory is extended on the fundamental level to statistically dependent subsystems introducing an 'ordering parameter' {kappa}. Particular forms for the entropy and partition functions are derived with superadditive (nonextensive) entropy, and a redefinition of temperature in such systems is given.

Treumann, R. A. [Department of Geophysics and Environmental Sciences, Munich University, D-80333 Munich (Germany); Department of Physics, Dartmouth College, Hanover, New Hampshire 03755 (United States); Jaroschek, C. H. [Department Earth and Planetary Science, University of Tokyo, Tokyo (Japan)

2008-04-18

200

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

NASA Astrophysics Data System (ADS)

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

Shen, Qunying

201

Radial Distribution Systems Power Flow with Distributed Generation: Modified Power Summation Method  

Microsoft Academic Search

In this work, the Power Summation Method is adapted to be applied in distribution systems that include distributed generation. The voltage control at the generation buses is treated as an optimization problem, which uses the Newton-Raphson method as the minimization technique. The algorithm is iterative and includes the reactive and voltage limits constraints for each generator. The accuracy and computational

Benemar Alencar de Souza; Helon David de Macedo Braz; Joao Marcelo Cavalcante de Albuquerque; Julio Guilherme Gerlach Gutterres

2006-01-01

202

A review of distributed power systems part I: DC distributed power system  

Microsoft Academic Search

The present development state in DC distributed power systems (DPS) is comprehensively reviewed in this tutorial. Basic distributed structures and their characteristics are described. The system level design considerations are discussed. The profile of current technologies is drawn. Finally, the issues and challenges in this research area are identified. These issues include not only improving efficiency, but also increased concerns

Shiguo Luo; ISSA BATARSEH

2005-01-01

203

A New Power Flow Method in Radial Distribution Systems  

Microsoft Academic Search

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

Wataru Ohyoshi; Hiroyuki Mori

2006-01-01

204

DC bus voltage control for a distributed power system  

Microsoft Academic Search

This paper addresses voltage control of distributed DC power systems. DC power systems have been discussed as a result of the introduction of renewable, small-scale power generation units. Also, telecommunication power systems featuring UPS properties might benefit from a broader introduction of DC power systems. Droop control is utilized to distribute the load between the source converters. In order to

P. Karlsson; J. Svensson

2003-01-01

205

Space power management and distribution status and trends  

Microsoft Academic Search

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

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

1984-01-01

206

Effect of ultrasonic power on the structure of activated carbon and the activities of Ru/AC catalyst.  

PubMed

Ruthenium-based materials are the second-generation catalysts for ammonia synthesis. Ruthenium is less inhibited by ammonia, less sensitive to poisons, and more active than the traditional iron-based catalyst. The relatively high cost of Ru compared to that of iron requires a high dispersion of the metal on a suitable support. Carbon-supported Ru catalysts with promoters have been reported to be active for ammonia synthesis. The ultrasonic technique has been proven to be beneficial to the preparation of supported catalysts. In this paper, the effects of ultrasonic treatment on the surface texture, oxygen groups of activated carbon (AC) as well as ruthenium dispersion were investigated by the employments of N(2) physisorption, TPD-MS and CO chemisorption respectively. It have been shown that ash content in AC can be effectively eliminated by ultrasonic pretreatment, at the same time, the BET surface area and total pore volume are reduced, and the amount of the decomposable surface oxygen groups are decreased. Furthermore the ash content decrease and the mesopore surface area increase with the ultrasonic power increasing. The activities of a series of barium-potassium-promoted Ru/AC catalysts for ammonia synthesis were tested at 10,000 h(-1), 10.0 MPa and 400 degrees C. The results show that the activities of Ru/AC catalysts which were prepared by ultrasonic treatment are greatly increased, and the optimum pretreatment power is 100 W. The ash content of this carbon support is decreased from 1.39% to 1.15%. As a result, the catalytic activity is improved from 65.3 to 83.8 mmol g(-1) h(-1). PMID:16782146

Yu, Fengwen; Ji, Jianbing; Xu, Zhichao; Liu, Huazhang

2006-06-02

207

Theory of the Brush-Shifting AC Motor ? IV Speed Control With Power-Factor Correction  

Microsoft Academic Search

The preceding papers of this series presented an analysis of the brush-shifting a-c motor. Parts I and II dealt with the case when the voltage introduced into the stator coils from the commutator was collinear with the voltage induced in the stator coils by slip. Part III dealt with the case when the voltage introduced into the stator coils from

A. G. Conrad; F. Zweig; J. G. Clarke

1942-01-01

208

Space-vector controlled soft-switching three-phase PDM AC\\/DC converter with unity power factor and sinusoidal line current  

Microsoft Academic Search

The authors present the state-of-the-art pulse density modulation (PDM)-type three-phase AC\\/DC power converter with an active voltage clamped resonant DC link (ACRDCL) network and its digital signal processor (DSP) based digital control strategy to achieve a unity power factor correction and sinewave line current shaping. The new operating principle of the zero-voltage soft-switched three-phase AC\\/DC converter with a ACRDCL and

K. Miyagawa; M. Nakaoka; Y. Ogino; Y. Murakami; K. Hayashi

1992-01-01

209

Interaction of lightning with power distribution lines  

NASA Astrophysics Data System (ADS)

Triggered-lightning experiments were conducted in 1996, 1999, and 2000 to study the responses of overhead power distribution lines to lightning at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. The lightning was artificially initiated (triggered) from natural thunderclouds using the rocket-and-wire technique, and its current was directed to a phase conductor at midspan or at a pole near the center of the line. Experimental results and associated EMTP modeling are presented in this dissertation for the following line configurations: (1)a two-conductor, 740-m overhead distribution line with 2 arrester stations in 1996; (2)a four- conductor, 245-m overhead distribution line with 2 arrester stations in 1999; and (3)a four-conductor, 829-m overhead distribution line with 6 arrester stations in 2000. The three-phase lines tested in 1999 and 2000 were standard designs of a major Florida power company. Lightning peak currents injected into the lines ranged from 7 to 57 kA. Voltages and currents were measured at various locations along the line. Video and photographic cameras were used to image lightning channels and detect line flashovers. The significant results of the research are (1)flashovers between conductors were observed, both accompanied and not accompanied by arrester failures, (2)an arrester failed on seven of eight direct lightning strikes to the line in 2000, (3)arcing between conductors may prevent failures of arresters connected to the struck phase, (4)the bulk of the lightning current flows from the struck phase to neutral through the arresters closest to the strike point, (5)the withstand energy of the arresters can be exceeded due to the contribution from multiple strokes and/or relatively low-level, long-lasting current components, (6)the distribution of charge transferred to ground among multiple neutral grounds, which is determined by low-frequency, low-current grounding resistances is different from the distribution of peak currents to ground, which is characterized by a rapid decrease of current with increasing distance from the strike point, (7)EMTP allows one to model the observed line behavior with reasonable accuracy, (8)overall, the standard lightning protection of the distribution lines tested does not appear to be adequate.

Mata, Carlos Tomas

210

Distributed Power Electronics for PV Systems (Presentation)  

SciTech Connect

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

Deline, C.

2011-12-01

211

Power quality and protection of electric distribution systems with small, dispersed generation devices  

NASA Astrophysics Data System (ADS)

There are several operational problems associated with the connection of small power sources, such as wind turbines and photovoltaic (PV) arrays, to an electric distribution system. In one study the harmonic distortion produced by a subdivision of PV arrays connected through line-commutated inverters was simulated. A second simulation study evaluated protection problems associated with the operation of dispersed ac generators. The purpose of these studies was to examine the adequacy of the electric utility industry's traditional practices and hardware for the operation of dispersed power sources. The results of these simulation studies are discussed and recommendations are given for hardware and system operation needed for accommodating this new technology.

Rizy, D. T.; Jewell, W. T.

1984-10-01

212

DC Micro-grid for Super High Quality Electric Power Distribution  

NASA Astrophysics Data System (ADS)

“DC Micro-grid" is a novel power system using dc distribution in order to provide a super high quality electric power. The dc distribution system is suitable for dc output type distributed generations such as photovoltaic and fuel cells, and energy storages such as batteries and electric double layer capacitors. Power is distributed through dc distribution line and converted to required ac or dc voltage by converters placed near loads. The load side converters do not need transformers by choosing proper distributed dc voltage. The spread scheme of converters contributes to provide a high quality power supplying. Even if a short circuit occurs at one load side, it does not effect other loads. In this paper, we propose a configuration of DC micro-grid and control methods of converters for generations and energy storages. Computer simulation results demonstrated the seamless operation during turn-on and turn-off of a distributed generation, the transient of connecting and disconnecting operation with bulk power system, and the stability against a sudden large load variation.

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

213

A new concept of electrical power supply for AC arc furnaces  

Microsoft Academic Search

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

G. Postiglione; P. Ladoux

2006-01-01

214

Power Flow Analysis for Balanced and Unbalanced Radial Distribution Systems  

Microsoft Academic Search

This paper reports on an efficient method of power flow analysis for solving balanced and unbalanced radial distribution systems. The radial distribution system is modelled as a series of interconnected single feeders. Using Kirchoff's laws, a set of iterative power flow equations was developed to conduct the power flow studies. Due to the voltage dependency of loads in distribution systems,

H. M. Mok; S. Elangovan; M. M. A. Salama; Cao Longjian

215

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

216

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

NASA Astrophysics Data System (ADS)

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

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

2006-01-01

217

A Control Strategy for a Distributed Power Generation Microgrid Application With Voltage and Current-Controlled Source Converter  

Microsoft Academic Search

This paper presents a pseudodroop control structure integrated within a microgrid system through distributed power generation (DPG) modules capable to function in off-grid islanded, genset-connected, and grid-connected modes of operation. System efficiency has an important role in order to harvest the maximum available renewable energy from dc or ac sources while providing power backup capability. A control strategy is proposed

Emanuel Serban; Helmine Serban

2010-01-01

218

Advanced power electronics enabled distribution architectures: Design, operation, and control  

Microsoft Academic Search

This paper explores how highly reliable power distribution architectures can be implemented, operated and controlled. Potential applications for advanced power distribution architectures include advanced micro-grid enabled smart grids, electric ships, and data centers. The analysis discusses power electronics circuit topologies and system wide architecture design. Some of the possible power architectures included radial, ring, and laddered topologies. Some commented relevant

Alexis Kwasinski

2011-01-01

219

Integration of distributed energy sources with electrical power grid  

Microsoft Academic Search

The changes that have been taking place recently in the power sector, lead to an increasing share of distributed generation (DG) in the electric power production. Many different energy sources can be distinguished in this area and majority of them incorporate power electronic electrical energy converters interfacing with a power system. Connection of a large number of distributed energy sources

I. WASIAK; Z. HANZELKA

220

Electrical power distribution on space based radar satellites  

Microsoft Academic Search

The radar payload on a space-based radar (SBR) satellite could require tens of kilowatts of power distributed to many small loads over a large area. This poses special problems for the power distribution and control system (PDCS). A study that examined the power requirements of an SBR spacecraft is reported. A baseline prime power system, generating about 30 kW, was

M. H. Moody; C. A. Maskell

1989-01-01

221

Robust distribution and use of electric power  

NASA Astrophysics Data System (ADS)

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

Catalan Izquierdo, Saturnino

2001-07-01

222

Optimization of Electric Power Distribution Using Hybrid Simulated Annealing Approach  

Microsoft Academic Search

The key goal of electric power distribution companies is to provide a high quality of service with a low cost of operation. The growing customer needs requires a re-distribution of the Power over various nodes of the Distributed Generation (DG) facilitates. The re-distribution might cause over load on various parts of the networks which if not correctly optimized might increase

Walid Ahmed; Alaa F. Sheta

2008-01-01

223

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

224

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

225

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

SciTech Connect

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

None

2010-09-01

226

AC over-current test results of YBCO conductor for YBCO power transformer with fault current limiting function  

NASA Astrophysics Data System (ADS)

We are developing elemental technology for 66 kV/6.9 kV 20 MVA-class YBCO power transformer. The YBCO transformer is considered to have a possibility to stabilize the power system by improving function of fault current limiting. Current limiting behavior functions over critical current flows. There is a possibility that superconducting characteristic may be damaged due to increase in temperature of YBCO tapes. Therefore, we have taken a measure to combine YBCO tape with CuNi tape or Cu Tape. We manufactured model coils using these conductors and conducted the AC over-current tests. The test current was two to seven times larger than the Ic of conductor and it was damped with time from its maximum value according to the generation of conductor resistance. We verified the effectiveness of current limiting characteristics.In these tests, the Ic of model coil did not degrade. We consider this conductor to be able to withstand AC over-current with the function of current limiting.

Tomioka, A.; Otonari, T.; Ogata, T.; Iwakuma, M.; Okamoto, H.; Hayashi, H.; Iijima, Y.; Saito, T.; Gosho, Y.; Tanabe, K.; Izumi, T.; Shiohara, Y.

2011-11-01

227

Device for the distribution of motive power  

SciTech Connect

A device is described for the distribution of motive power comprising: a hollow shaft receiving input power from the drive device; a pinion shaft provided on the output side of the hollow shaft; a pinion gear rotatably supported on the pinion shaft; a pair of side gears meshed with the pinion gear; a front wheel drive shaft integrally coupled to one of the side gears and passing through the center of the hollow shaft; a differential case having an outer shell, a front and a rear end and being integrally formed with the outer side gear and enclosing the pinion shaft, pinion gear and side gears. A rear wheel drive shaft is coupled to the differential case through a drive gear formed on the outer shell of the differential case and an input gear is integrally connected to an end of the rear wheel drive shaft so as to mesh with the drive gear, the rear drive wheel drive shaft being located above the front wheel drive shaft.

Teroka, M.

1986-12-30

228

Decoupling capacitors for power distribution systems with multiple power supply voltages  

Microsoft Academic Search

To decrease power consumption without affecting circuit speed, several power supply voltages are used in modern high performance ICs such as microprocessors. To maintain the impedance of a power distribution system below a specified level, multiple decoupling capacitors are placed at different levels of the power grid hierarchy. The system of decoupling capacitors used in power distribution systems with multiple

Mikhail Popovich; Eby G. Friedman

2004-01-01

229

Trends in AC\\/DC switching power supplies and DC\\/DC converters  

Microsoft Academic Search

A survey of key original equipment manufacturer (OEM) specifiers of power supplies reveals a number of changing power supply requirements. In particular, purchasers of AD\\/DC switchers are tending to add power factor correction and universal input voltages. There will be growing demand for 3.3 V outputs, and power requirements will generally move in a downward direction. DC\\/DC converter specifiers plan

M. Klapfish

1993-01-01

230

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

231

Application for fault location in electrical power distribution systems  

Microsoft Academic Search

Fault location has been studied deeply for transmission lines due to its importance in power systems. Nowadays the problem of fault location on distribution systems is receiving special attention mainly because of the power quality regulations. In this context, this paper presents an application software developed in Matlabtrade that automatically calculates the location of a fault in a distribution power

S. Herraiz; J. Melendez; G. Ribugent; J. Sanchez; M. Castro

2007-01-01

232

Fast decoupled power flow for unbalanced radial distribution systems  

Microsoft Academic Search

This paper presents a novel power flow formulation and an effective solution method for general unbalanced radial distribution systems. Comprehensive models are considered including lines, switches, transformers, shunt capacitors, cogenerators, and several types of loads. A new problem formulation of three-phase distribution power flow equations taking into account the radial structure of the distribution network is presented. A distinguishing feature

Ray D. Zimmerman; Hsiao-Dong Chiang

1995-01-01

233

Distributed control system approach for a unified power system  

Microsoft Academic Search

This paper presents an approach for applying distributed control system, DCS for a unified power system. It is well known that the distributed control system is usually serves to control, largescale systems, such as unified power systems, production lines in factories, airplanes, and airport earth services. The proposed distributed control system consists of hardware software and a number of controllers

M. Z. El-Sadek; A. M. Hemeida; M. A. Abelwahab; A. Alkosy; S. A. Younies

2004-01-01

234

A comparison of distributed optimal power flow algorithms  

Microsoft Academic Search

We present an approach to parallelizing optimal power flow (OPF) that is suitable for coarse-grained distributed implementation and is applicable to very large interconnected power systems. The proposed distributed scheme can be used to coordinate a heterogeneous collection of utilities. Three mathematical decomposition coordination methods are introduced to implement the proposed distributed scheme: the auxiliary problem principle (APP), the predictor-corrector

Balho H. Kim; Ross Baldick

2000-01-01

235

LARGE POWER TRANSFORMER RELIABILITY IMPROVEMENT IN ESKOM DISTRIBUTION  

Microsoft Academic Search

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

Lester GELDENHUIS; Janine JAGERS; Trevor GAUNT

2007-01-01

236

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

237

The Design of Low-voltage Welding Power Distribution  

Microsoft Academic Search

This paper is an effort to state clearly and to present a solution for the problems encountered in the design of one of the vital constituents of a-c restance-welder power supply¿the low-voltage feeder. The scope of the paper is much wider, however, since the determination of design loads from the probability standpoint for the purpose of determining maximum allowable impedance

Comfort A. Adams; John R. Fetcher; Arthur C. Johnson

1944-01-01

238

Fully integrated power-efficient AC-to-DC converter design in inductively-powered biomedical applications  

Microsoft Academic Search

In this paper we have reviewed several types of integrated ACtoDC converters which have been widely used for inductivelypowered applications. The limitations for achieving high power conversion efficiency (PCE) in each ACtoDC converter have been considered in order to design highly power? efficient converters for applications that are in need of higher power levels with very low heat dissipation, such

Hyung-Min Lee; Maysam Ghovanloo

2011-01-01

239

Verification of the new concept in AC power theory using energy conversion medium  

Microsoft Academic Search

In this article, the nature of reactive power is investigated. It is shown that the separation of instantaneous power into two useful and nonuseful energy related elements does not fulfil the basic energy relationship of the circuit and that active circuit elements are also related to the exchange of energy between source and load. An ideal synchronous generator model is

F. Ghassemi

2000-01-01

240

Single stage AC\\/DC converter with input power factor correction  

Microsoft Academic Search

The full-bridge converter with isolation transformer is the preferred topology for medium and high power SMPS. A simple topology modification, i.e. the addition of two input inductors, and appropriate control methods permit to control simultaneously and accurately the output voltage and the input current, performing a new single stage SMPS. The circuit behaviour is strongly dependent on the output power

Victor Anunciada; Hugo Ribeiro

2003-01-01

241

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

Microsoft Academic Search

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

Philippe Ladoux; Gianluca Postiglione; Henri Foch; Jacques Nuns

2005-01-01

242

Power line carrier on insulated bundle subconductors of dc and ac transmission lines  

Microsoft Academic Search

There is a great interest in power line carrier facilities because of their inherent reliability, and because of an increasing demand for transmission of data for protection, control, and optimization of power system operation. Improved isolation of carrier signals to the desired line section may permit increased usage of the limited carrier frequency spectrum. On dc lines, the inherent rejection

Perz

1967-01-01

243

Distributed Discrete Power Control in Cellular PCS  

Microsoft Academic Search

Transmitter power control has proven to be an efficient method to control cochannel interference in cellular PCS, and to increase bandwidth utilization. Power control can also improve channel quality, lower the power consumption, and facilitate network management functions such as mobile removals, hand-off and admission control. Most of the previous studies have assumed that the transmitter power level is controlled

M. ANDERSIN; Z. ROSBERG; J. ZANDER

1996-01-01

244

Distributed Discrete Power Control in Cellular PCS  

Microsoft Academic Search

Transmitter power control has proven to be an efficient method to control cochannel interference in cellular PCS, and to increase bandwidth utilization. Power control can also improve channel quality, lower the power consumption, and facilitate network management functions such as mobile removals, hand-off and admission control. Most of the previous studies have assumed that the transmitter power level is controlled

M. Andersin; Z. Rosberg; J. Zander

1998-01-01

245

Effect of hydrostatic pressure on the space charge distribution in power cable materials  

NASA Astrophysics Data System (ADS)

The performance of high-voltage cables with synthetic insulation is highly dependent on the appearance of a space charge under AC or DC stress. The presence of this charge plays a very important role in aging and polymer breakdown phenomena. For submarine power cables, the pressure P for the immersion depth of the cables is now considered. We then study the effect this has on the space charge distribution, as a function of the amplitude of the stressed applied, DC voltage, temperature and hydrostatic pressure. Preliminary results obtained with cross-linked polyethylene are given.

Garros, B.; Santana, J.

1993-06-01

246

Using Super Capacitor Based Energy Storage to Improve Power Quality in Distributed Power Generation  

Microsoft Academic Search

Distributed power generation will be formed in many weak distribution networks, after renewable energy sources are connected to them. It is very important to increase the reliability and efficiency of using these renewable energy sources. By using DVR (dynamic voltage restorer), the power quality problem in distributed power generation (e.g. voltage fluctuation) can effectively be solved. In this paper, super

Yonghua Chen; J. Van Mierlo; P. Van den Bossche; P. Lataire

2006-01-01

247

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

NASA Astrophysics Data System (ADS)

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 50 kWe to one-half of the ion thrusters and science modules, but is capable of supplying the total power requirements 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.

2004-02-01

248

Power-law distributions resulting from %nite resources  

Microsoft Academic Search

An elementary stochastic model, termed the normalization model, is put forward which does demonstrate that power-laws generically occur in systems with %nite resources. The model is capable to exhibit power-law distributions with arbitrary power law exponents; nevertheless, for a large fraction of the parameter space power law exponents near unity are obtained. As an application of the normalization mechanism we

Thomas Wilhelma; Peter H

249

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

Microsoft Academic Search

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,

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

1987-01-01

250

AC/DC Power Conditioning and Control Equipment for Advanced Conversion and Storage Technology.  

National Technical Information Service (NTIS)

The objective of this project is to establish the best power conversion technology (technologies) applicable to a number of advanced energy storage conversion technologies, including a study of common conversion technology, modular approach to constructio...

P. Wood

1975-01-01

251

ac\\/dc power converter for batteries and fuel cells. Annual report  

Microsoft Academic Search

The overall objective of the EPRI RP841-1 program is the design of an advanced power converter for use in both battery energy storage and fuel cell generation systems in the 1980's. This goal will be accomplished by expansion of United's existing FCG-1 fuel cell power conditioning inverter into a high-efficiency inverter--rectifier system employing improved commutation circuits and advanced (1980's) semiconductor

Rosati

1978-01-01

252

A Novel Asymmetric Distribution with Power Tails  

Microsoft Academic Search

In this article, we propose a four-parameter asymmetric doubly Pareto-uniform (DPU) distribution with support (??, ?) whose density and cumulative distribution functions are constructed by seamlessly concatenating the left and right Pareto tails with a uniform central part. Properties of the distribution are described and a maximum likelihood estimation (MLE) procedure for its parameters is obtained. Two illustrative examples of

Amita Singh; J. René van Dorp; Thomas A. Mazzuchi

2007-01-01

253

Characterization of Stand Alone AC Generators During No-Break Power Transfer Using Radial Basis Networks  

Microsoft Academic Search

This paper describes the use of an artificial intelligence-electromagnetic modeling approach for the performance prediction of stand alone synchronous generators during no break power transfer (NBPT) operating conditions. This approach uses radial basis networks (RBNs), which have the advantage of not being locked into local minima as could do feedforward neural networks. The RBNs are simply linear function approximators that

A. A. Arkadan; Y. Abou-Samra; N. Al-Aawar

2007-01-01

254

Damping of low frequency oscillations in AC-DC interconnected power system using robust modulation controller  

Microsoft Academic Search

this paper presents a systematic design procedure based on H? optimization technique for damping low frequency electromechanical oscillations in a HVDC link for a wide range of operation conditions. It is shown that the suggested method can improve the dynamic stability of system and it can perfectly consider the uncertainties of the power system. The simulation results verify the capability

K. Rahmani; G. B. Gharehpetian; M. S. Naderi

2010-01-01

255

Strategies for the interconnection of off-shore power systems to shore using AC or DC  

Microsoft Academic Search

This paper deals with the problem of choice whether the best solution for interconnecting off-shore power systems is via High Voltage Alternate Current (HVAC) or Direct Current (HVDC) transmission. The typical off-shore interconnection strategies based on HVAC and HVDC technologies are illustrated from the technical and economical point of view, with reference to some practical examples.

P. La Seta; E. Lerch

2010-01-01

256

Theory of the brush-shifting AC Motor - III power-factor correction  

Microsoft Academic Search

In the preceding papers1 of this series a method was described for determining the circle diagram and predicting the characteristics for the brush-shifting motor as it is used when the brushes are shifted to control speed. This paper extends the earlier work to show how the motor can be used to correct power factor. The range and limitations for this

A. G. Conrad; F. Zweig; J. G. Clarke

1942-01-01

257

Inverse Power Law distribution and failure initiation of subaerial landslides  

Microsoft Academic Search

Landslides are sometimes considered together with other natural hazards, such as earthquakes and fires, as a cascading avalanche or self-organized critical process, where the disturbance initiates in one or a few locations and propagates to the entire region. This view stems from numerous studies of subaerial landslides that show an inverse power law size distribution. Inverse power law distributions are

R. Barkan; B. D. Andrews; J. D. Chaytor

2009-01-01

258

Assessment of distributed solar power systems: Issues and impacts  

Microsoft Academic Search

The installation of distributed solar-power systems presents electric utilities with a host of questions. Some of the technical and economic impacts of these systems are discussed. Among the technical interconnect issues are isolated operation, power quality, line safety, and metering options. Economic issues include user purchase criteria, structures and installation costs, marketing and product distribution costs, and interconnect costs. An

R. A. Moyle; H. Chernoff; T. C. Schweizer; J. B. Patton

1982-01-01

259

Service restoration of power distribution systems incorporating load curtailment  

Microsoft Academic Search

Power distribution systems are now integrating Smart Grid technologies allowing for widespread implementation of demand response and direct load control. This paper will present a service restoration problem formulation and solution algorithm for power distribution systems which incorporates load curtailment. A ranking based heuristic search algorithm is proposed which prioritizes the multi-objective service restoration problem and returns a new system

Michael Kleinberg; Karen Miu; Hsiao-Dong Chiang

2009-01-01

260

A User-Oriented Power Distribution System Analysis Program.  

National Technical Information Service (NTIS)

This paper is a revision of a digital computer program written to perform a load flow and/or short circuit analysis of a power distribution system. The program has been named Power Distribution System Analysis Program (PDSAP). The program capacity is 250 ...

J. A. Underwood

1976-01-01

261

A User-Simplified Power Distribution System Analysis Program.  

National Technical Information Service (NTIS)

The paper addresses the problem of developing a user-simplified power distribution system analysis program. A computer program was written to perform a load-flow and/or short-circuit analysis of a power distribution system. The program utilizes sparsity p...

M. R. Heer

1975-01-01

262

The electrical power distribution system for the nonelectrical engineer  

Microsoft Academic Search

An attempt is made to introduce to the nonelectrical engineer the basic components and terminologies associated with a power distribution system and to present the needs such a system requires to remain safe and reliable. Particular reference is made to the power distribution system of a cement plant

Robert A. Haas; M. J. Klova

1991-01-01

263

Communication Using Pseudonoise Modulation on Electric Power Distribution Circuits  

Microsoft Academic Search

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

P. van der Gracht; R. W. Donaldson

1985-01-01

264

The Load Forecasting Technology in the Electric Power Distribution System  

Microsoft Academic Search

We proposed the technology which estimates an electric current value at the time each being positive for each power distribution line. Generally, as for the reported demand forecast (for example, are demand forecast by the electricity supply place level and so on), to consider that the load which becomes a base moves isn't necessary. However, as for the power distribution

Tsuneyo Sano; Itsuko Tezuka; Yoshihiro Fukuda

2004-01-01

265

Power Distribution of Hybrid Electric Vehicles  

NASA Astrophysics Data System (ADS)

In this paper, the fuel consumption of the hybrid electric vehicles is analyzed by the rated power of the engine and the motor. The analysis was based on the published data only. Hybrid ratio and normalized fuel consumption are defined. As the result, the key for the high mileage of hybrid electric vehicle is to use the high power motor and the low power engine.

Kato, Kenta; Morimoto, Masayuki

266

Grid integration of wind-solar hybrid renewables using AC\\/DC converters as DG power sources  

Microsoft Academic Search

Renewable Energy Resources are best practices possible today to stand against increasingly risk of climate changes and global warming of the world and the most important sources of such types of resources of energies can be Wind and Solar energies which are most the efficient relatively. These clean power resources are used as in Distributed Generation (DGs) units technology to

Saeed Jahdi; Loi Lei Lai; Daniel Nankoo

2011-01-01

267

Appartus for identifying defective electric power distribution capacitors  

SciTech Connect

An apparatus for determining the operating condition of capacitors of the type used for power factor correction on electric distribution systems is assembled in two sections. A first power supply device supplies an alternating electric current to a de-energized capacitor without removing it from its installed position and a second power measurement device, utilizing either a split-core Hall-device or a special distributed winding, measures the magnitude of the electric current entering the capacitor being tested.

Burkum, M. E.; O'Regan, T. M.

1985-09-10

268

Electrical power generation and distribution system  

Microsoft Academic Search

Problems associated with moving fuel from remote sources to large centralized power generation plants are avoided with an economical system for collecting power from small stations located near the scattered, remote fuel sites. To avoid a need for many massive, costly transformers, a plurality of relatively low voltage generating stations are connected in series to cumulatively produce the high voltage

Jeppson

1977-01-01

269

AC switches with integrated gate driver supplies  

Microsoft Academic Search

Monolithic integration dedicated to power electronics applications simplifies design and implementation of converters. This paper presents a simple and highly integrated gate driver powering technique for AC switches and AC to AC converters. Gate driver supply operating principle and integration are first recalled. Then, it is shown how the proposed solution can easily be implemented into or within AC switches

Binh-Dac NGUYEN; JeanChristophe CREBIER; Radoslava MITOVA; L. Aubard; Christian SCHAEFFER

2005-01-01

270

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

271

A high efficiency broadband monolithic gallium nitride distributed power amplifier  

Microsoft Academic Search

A 50-ohm 100-2200 MHz distributed power amplifier (DPA) MMIC has been developed using Nitronexpsilas proprietary GaN-on-Si NRF1 process. The DPA MMIC exhibits -10dB minimum input\\/output return loss, 39.4 dBm average output power, and a power added efficiencies of 30 to 66% over the entire bandwidth.

Chenggang Xie; Jeanne Pavio; David A. Griffey; A. Hanson; Sameer Singhal

2008-01-01

272

A new on-chip all-digital three-phase full-bridge dc/ac power inverter with feedforward and frequency control techniques.  

PubMed

The communication speed between components is far from satisfactory. To achieve high speed, simple control system configuration, and low cost, a new on-chip all-digital three-phase dc/ac power inverter using feedforward and frequency control techniques is proposed. The controller of the proposed power inverter, called the shift register, consists of six-stage D-latch flip-flops with a goal of achieving low-power consumption and area efficiency. Variable frequency is achieved by controlling the clocks of the shift register. One advantage regarding the data signal (D) and the common clock (CK) is that, regardless of the phase difference between the two, all of the D-latch flip-flops are capable of delaying data by one CK period. To ensure stability, the frequency of CK must be six times higher than that of D. The operation frequency of the proposed power inverter ranges from 10 Hz to 2 MHz, and the maximum output loading current is 0.8 A. The prototype of the proposed circuit has been fabricated with TSMC 0.35 ?m 2P4M CMOS processes. The total chip area is 2.333 x 1.698 mm2. The three-phase dc/ac power inverter is applicable in uninterrupted power supplies, cold cathode fluorescent lamps, and motors, because of its ability to convert the dc supply voltage into the three-phase ac power sources. PMID:20875981

Chen, Jiann-Jong; Kung, Che-Min

2010-09-01

273

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

274

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

275

Power System Information Delivering System Based on Distributed Object  

NASA Astrophysics Data System (ADS)

In recent years, improvement in computer performance and development of computer network technology or the distributed information processing technology has a remarkable thing. Moreover, the deregulation is starting and will be spreading in the electric power industry in Japan. Consequently, power suppliers are required to supply low cost power with high quality services to customers. Corresponding to these movements the authors have been proposed SCOPE (System Configuration Of PowEr control system) architecture for distributed EMS/SCADA (Energy Management Systems / Supervisory Control and Data Acquisition) system based on distributed object technology, which offers the flexibility and expandability adapting those movements. In this paper, the authors introduce a prototype of the power system information delivering system, which was developed based on SCOPE architecture. This paper describes the architecture and the evaluation results of this prototype system. The power system information delivering system supplies useful power systems information such as electric power failures to the customers using Internet and distributed object technology. This system is new type of SCADA system which monitors failure of power transmission system and power distribution system with geographic information integrated way.

Tanaka, Tatsuji; Tsuchiya, Takehiko; Tamura, Setsuo; Seki, Tomomichi; Kubota, Kenji

276

Determining the impact of distributed generation on power systems. I. Radial distribution systems  

Microsoft Academic Search

Distributed generation (DG) has much potential to improve distribution system performance and it should be encouraged. However, distribution system designs and operating practices are normally based on radial power flows and this creates a special challenge to the successful introduction of distributed generation. This paper has described a few of the issues that must be considered to insure that DG

Philip P. Barker; Robert W. de Mello

2000-01-01

277

Distribution Power Flow for Smart Grid Technologies  

SciTech Connect

Smart Grid technologies hold the promise of being able to solve many of the problems currently facing in the electric power industry. However, the large scale deployment of these new technologies has been limited due to an inability to accurately model their effects or to quantify their potential benefits. GridLAB-D is a new open source power system modeling and simulation environment developed by the United States Department of Energy specifically to integrate detailed power systems and end-use models. In order to effectively model the vast array of possible smart grid technologies GridLAB-D was developed as a general simulation environment. This paper describes the basic design concept, the power flow solutions implemented, and a detailed example of the type of analysis that can be performed within the simulation environment in order to support the evaluation of smart grid technologies.

Schneider, Kevin P.; Chassin, David P.; Chen, Yousu; Fuller, Jason C.

2009-03-18

278

Analysis and Design of a Modular Three-Phase AC-to-DC Converter Using CUK Rectifier Module With Nearly Unity Power Factor and Fast Dynamic Response  

Microsoft Academic Search

In this paper, the analysis and design of a modular three-phase AC-to-DC converter using single-phase isolated Cuk rectifier modules is discussed based on power balance control technique. This paper analyzes the operation of a modular converter as continuous-conduction-mode power factor correction (CCM-PFC). Design equations, as well as an average small-signal model of the proposed system to aid the control loop

Uthen Kamnarn; Viboon Chunkag

2009-01-01

279

Statistical Analyses Support Power Law Distributions Found in Neuronal Avalanches  

PubMed Central

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

Klaus, Andreas; Yu, Shan; Plenz, Dietmar

2011-01-01

280

A Matrix– Source Converter With AC–DC Bidirectional Power Flow for an Integrated Starter Alternator System  

Microsoft Academic Search

This paper proposes a new converter using matrix converter theories and Z-source conversion concepts and illustrates its application for the integrated starter\\/alternator (ISA) system by a case study. The problem imposed by the traditional voltage source inverter to develop the relatively high dc voltage from the relatively low ac voltages of an ac machine in the ISA system has been

Keping You; M. F. Rahman

2009-01-01

281

Ac/Ds-transposon activation tagging in poplar: a powerful tool for gene discovery  

PubMed Central

Background Rapid improvements in the development of new sequencing technologies have led to the availability of genome sequences of more than 300 organisms today. Thanks to bioinformatic analyses, prediction of gene models and protein-coding transcripts has become feasible. Various reverse and forward genetics strategies have been followed to determine the functions of these gene models and regulatory sequences. Using T-DNA or transposons as tags, significant progress has been made by using "Knock-in" approaches ("gain-of-function" or "activation tagging") in different plant species but not in perennial plants species, e.g. long-lived trees. Here, large scale gene tagging resources are still lacking. Results We describe the first application of an inducible transposon-based activation tagging system for a perennial plant species, as example a poplar hybrid (P. tremula L. × P. tremuloides Michx.). Four activation-tagged populations comprising a total of 12,083 individuals derived from 23 independent "Activation Tagging Ds" (ATDs) transgenic lines were produced and phenotyped. To date, 29 putative variants have been isolated and new ATDs genomic positions were successfully determined for 24 of those. Sequences obtained were blasted against the publicly available genome sequence of P. trichocarpa v2.0 (Phytozome v7.0; http://www.phytozome.net/poplar) revealing possible transcripts for 17 variants. In a second approach, 300 randomly selected individuals without any obvious phenotypic alterations were screened for ATDs excision. For one third of those transposition of ATDs was confirmed and in about 5% of these cases genes were tagged. Conclusions The novel strategy of first genotyping and then phenotyping a tagging population as proposed here is, in particular, applicable for long-lived, difficult to transform plant species. We could demonstrate the power of the ATDs transposon approach and the simplicity to induce ATDs transposition in vitro. Since a transposon is able to pass chromosomal boundaries, only very few primary transposon-carrying transgenic lines are required for the establishment of large transposon tagging populations. In contrast to T-DNA-based activation tagging, which is plagued by a lack of transformation efficiency and its time consuming nature, this for the first time, makes it feasible one day to tag (similarly to Arabidopsis) every gene within a perennial plant genome.

2012-01-01

282

A small scale solar power generation, distribution, storage, MPPT and completed system design method  

Microsoft Academic Search

The main objective of this paper is to a DC to AC Inverter and power switching system. Our final goal is to achieve a stable output of 110VAC, and be able to self-generate the drive voltage and switching the power supply between the city electrical system and solar power system. Solar power driver circuit which contains the theory, simulation and

Yun-Parn Lee; En-Chi Liu; Huang-Yao Huang

2010-01-01

283

Gas-Insulated Transformers for Distribution and Power Receiving.  

National Technical Information Service (NTIS)

Protection against fire hazards, harmony with the environment, and small size are very important for the distribution and power-receiving facilities of urban buildings. Gas-insulated transformers are ideal for such applications, and are already being inst...

T. Sato M. Matsumoto K. Tamura

1984-01-01

284

Energy loss analysis of an integrated space power distribution system  

NASA Astrophysics Data System (ADS)

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. D.; Ribeiro, P. F.

285

Power, Distributive Conflicts, and Multiple Growth Paths  

Microsoft Academic Search

This article shows that multiple growth paths may occurin a politico-economic model of endogenous growth. This multiplicityis characterized by the coexistence of the low-tax, low-capital-flightequilibrium and a high-tax, high-capital-flight equilibrium.The likelihood of multiplicity is crucially related to the structureof power in society—namely, it is necessary that the politicallydecisive agents have a greater access to international capitalmarkets than the average in

Gilles Saint Paul; Thierry Verdier

1997-01-01

286

Power Distribution System Planning with GIS Consideration  

NASA Astrophysics Data System (ADS)

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

Wattanasophon, Sirichai; Eua-Arporn, Bundhit

287

Formulas for Predicting Audible Noise from Overhead High Voltage AC and DC Lines  

Microsoft Academic Search

This paper describes Bonneville Power Administration's basic philosophy for predicting audible noise from ac and dc high voltage transmission lines. General formulas for predicting the A-weighted audible noise during rain for ac lines and during fair weather for dc lines which were developed from data from full-scale lines are presented. From this basic calculation, audible noise cumulative distributions, frequency spectrums,

V. L. Chartier; R. D. Stearns

1981-01-01

288

An AC processing pickup for IPT systems  

Microsoft Academic Search

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

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

2009-01-01

289

Investigating the Electric Power Distribution System (EPDS) Bus Voltage in the Presence of Distributed Generation (DG)  

Microsoft Academic Search

This paper investigates the Electric Power Distribution System (EPDS) bus voltage in the presence of Distributed Generation (DG). Distribution Company's (Discos) planner endeavor to develop new planning strategies for their network in order to serve the load growth and provide their customers with a reliable electric supply. In this research work, five different cases including preplanned islanding and grid-connected mode

Hasham Khan; Mohammad Ahmad Choudhry; Tahir Mahmood; Aamir Hanif

2006-01-01

290

Optimal reactive power and voltage control for radial distribution system  

Microsoft Academic Search

A new approach to optimal reactive power and voltage control problem in a radial distribution system is proposed in this paper. The optimal control problem is to find a proper dispatch schedule for shunt capacitor banks and on-load tap changer at substation and shunt capacitor banks on feeders such that the power loss is minimized and the voltage profile is

Yutian Liu; Peng Zhang; Xizhao Qiu

2000-01-01

291

The HEMP Response of an Overhead Power Distribution Line  

Microsoft Academic Search

The level of transient electrical surges in power system distribution lines plays an important role in determining the overall response of the electrical power network to a high altitude electromagnetic pulse (HEMP) produced by a nuclear explosion. A previous paper has discussed a multiconductor coupling model which permits the computation of the HEMP-induced voltage surges on above-ground lines, given a

F. M. Tesche; P. R. Barnes

1989-01-01

292

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

293

A fast distributed implementation of optimal power flow  

Microsoft Academic Search

The authors describe a distributed implementation of optimal power flow on a network of workstations. High performance is achieved on large real-world systems, including a 2587 line representation of the ERCOT system. The approach illustrates a general framework for parallelizing power system optimization problems

R. Baldick; B. H. Kim; C. Chase; Yufeng Luo

1999-01-01

294

A robust decoupled power flow for distribution systems  

Microsoft Academic Search

This paper presents a robust decoupled power flow technique based on line current flows in rectangular coordinates for radial distribution systems. The functions of line current flows and their equivalent values, which are computed from the specified load powers, are linearised around a known operating point and transformed through a constant matrix with a view to eliminate the off-diagonal blocks

P. Aravindhababu; R. Ashokkumar

2011-01-01

295

Optimal preventive maintenance budget setting for electric power distribution utilities  

Microsoft Academic Search

This paper proposes a practical method of preventive maintenance budget setting for electric power distribution utilities. Power system reliability mainly depends on preventive maintenance programs including types and frequency of selected maintenance activities controlled by maintenance budgets. In this paper, particle swarm optimization (PSO) is used to find the optimal budget settings in order to minimize the outage costs of

N. Phoothong; P. Vanittanakom; N. Teera-achariyakul; D. Rerkpreedapong

2008-01-01

296

Electrical power distribution system operating experience review for fusion applications  

Microsoft Academic Search

This paper describes safety research on electrical distribution systems applicable to fusion facilities. Electrical power has many uses in both magnetic and inertial fusion experiments; it is the most important support system for any fusion experiment. Electricity powers a wide variety of plant equipment, including vacuum pumps, magnets, coolant pumps, air handlers, compressors, and either plasma heating or target implosion

L. C Cadwallader

2002-01-01

297

Network reconfiguration at the power distribution system with dispersed generations for loss reduction  

Microsoft Academic Search

This paper discusses the network reconfiguration at the power distribution systems with dispersed generations (DG) for loss reduction. The power distribution systems have a radial network and unidirectional power flows. With the advent of dispersed generations, the power distribution systems have a locally looped network and bidirectional power flows. Therefore, DG into the power distribution system can cause operational problems

Joon-Ho Choi; Jae-Chul Kim

2000-01-01

298

Integration of D-Statcom based photovoltaic cell power in low voltage power distribution grid  

Microsoft Academic Search

The main aim of this paper is the voltage regulation which is one of the most important operational requirement in power network at both transmission and distribution levels. Whenever there is a penetration of photovoltaic cell power to the low voltage distributed grid, there occur the problem of mismatch in voltage and frequency in the network, perhaps caused by non

R. Indumathi; M. Venkateshkumar; R. Raghavan

2012-01-01

299

Software framework concepts for power distribution system analysis  

Microsoft Academic Search

Software design reuse has been discussed in the past at the component level through Design Patterns. A software framework is an approach to achieve software reusability for an entire domain. This paper presents architectural design concepts of a framework for power distribution system analysis. The commonalities of distribution system analysis, including components, topologies, and algorithms are considered. A layered architecture

Fangxing Li; Robert P. Broadwater

2004-01-01

300

Power law distribution of dividends in horse races  

Microsoft Academic Search

We discovered that the distribution of dividends in Korean horse races follows a power law. A simple model of betting is proposed, which reproduces the observed distribution. The model provides a mechanism to arrive at the true underlying winning probabilities, which are initially unknown, in a self-organized collective fashion, through the dynamic process of betting. Numerical simulations yield excellent agreement

E. Domany

2001-01-01

301

Assessment of distributed photovoltaic electric-power systems. Final report  

Microsoft Academic Search

The purpose of this study was to develop a methodology for assessing 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. The investigations focused upon five specific utilities. Three were actual planned future systems for Northeast Utilities Service Company, Alabama Power Company, and

R. W. Neal; P. F. DeDuck; R. N. Marshall

1982-01-01

302

Assessment of distributed photovoltaic electric-power systems. Summary report  

Microsoft Academic Search

The purpose of this study was to develop a methodology for assessing 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. The investigations focused upon five specific utilities. Three were actual planned future systems for Northeast Utilities Service Company, Alabama Power Company, and

R. W. Neal; P. F. DeDuck; R. N. Marshall

1982-01-01

303

Power Control Center Applications using Highly Available Distributed RAM (HADRAM)  

Microsoft Academic Search

With on-going deregulation, with tighter interdependence between energy providers, and with growing demands on reliability, Power Control Centers (PCC) need to both scale up and to allow access to comprehensive real-time data. In this paper, we propose to build PCCs based on geographically distributed and tightly coupled clusters of heterogeneous computer clusters. Our proposal, Highly Available Distributed Random Access Memory

Damian Cieslicki; Thomas Schwarz

304

Using smart devices to provide distributed reactive power support  

Microsoft Academic Search

Smart devices are becoming more common. Many of them already possess the hardware and software capabilities to implement the reactive power injection control as discussed in this paper. In the near future, such devices would be dispersed over a large portion of the electric distribution network, thus making distributed reactive voltage support feasible. This paper presents network-level benefits of such

Saurav Mohapatra; Christopher J. Recio; Thomas J. Overbye

2011-01-01

305

The distribution of leadership and power in schools  

Microsoft Academic Search

Distributed leadership has come to prominence in school management discourse as a means to achieve the participation and empowerment of teachers and to create democratic schools. In this paper I explore the contradictions between these claims and both the hierarchical power structure of schools and the use of distributed leadership to secure the commitment of teachers to government education agendas.

Richard Hatcher

2005-01-01

306

Automated fault location and diagnosis on electric power distribution feeders  

Microsoft Academic Search

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

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

1997-01-01

307

Influence of electric power distribution system design on harmonic propagation  

Microsoft Academic Search

The impact of the design parameters of electric power distribution systems on the propagation of harmonic distortion is investigated. This conceptual study is based on simulations on a generalized distribution system model, and leads to an increased insight in the mechanisms of the generation and propagation of voltage distortion. Moreover, analytical expressions are presented that predict the impact of changing

J. A. Ghijselen; W. A. Ryckaert; J. A. Melkebeek

2004-01-01

308

Topologies and design considerations for distributed power system applications  

Microsoft Academic Search

This paper describes developments in the technology of converters primarily intended for server-type distributed power system (DPS) applications. The paper first addresses the single-phase two-stage DPS, discussing the available options for simple power factor correction and high-performance DC-DC converters. Next, the concept is extended to three-phase high-power front-end converters, which also use a two-stage approach. Finally the paper presents the

FRED C. LEE; PETER BARBOSA; Peng Xu; Jindong Zhang; Bo Yang; FRANCISCO CANALES

2001-01-01

309

A distributed DC power system in an isolated island  

Microsoft Academic Search

This paper deals with a DC-micro grid in an isolated island. The proposed method is composed of gearless wind power generation system, battery, and DC loads in DC distribution system. The battery can avoid DC over-voltages by absorbing the PMSG power during line-fault. In addition, the control schemes in this paper include the maximum power point tracking (MPPT) control and

Kyohei Kurohane; Tomonobu Senjyu; Yuri Yonaha; Atsushi Yona; Toshihisa Funabashi; Chul-Hwan Kim

2009-01-01

310

A Fast Decoupled Power Flow for Distribution Systems  

Microsoft Academic Search

This article presents a fast decoupled power-flow (FDPF) technique based on line current flows in rectangular coordinates for radial distribution systems. The line current flows, computed from the specified load powers and its functions, are rotated by appropriate line admittance angles for zeroing the off-diagonal blocks of the Jacobian and decoupling the power-flow problem into two sub-problems without making any

P. Aravindhababu; R. Ashokkumar

2008-01-01

311

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

2013-06-04

312

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

313

The Load Forecasting Technology in the Electric Power Distribution System  

NASA Astrophysics Data System (ADS)

We proposed the technology which estimates an electric current value at the time each being positive for each power distribution line. Generally, as for the reported demand forecast (for example, are demand forecast by the electricity supply place level and so on), to consider that the load which becomes a base moves isn’t necessary. However, as for the power distribution system, the change of the composition which is due to the system changing, and so on, and the load curve shape, too, have changed mainly. So, the section of the power distribution line was classified in four kinds of clusters by the composition ratio of every contract classification, and created in the estimate model by the multiple regression analysis. Furthermore, to improve the precision of the estimate model, we calculated an error coefficient of each power distribution line and established the error revision method which distributes an error coefficient to each section. As a result, the absolute average error with estimate electric current value by this technique was 7.7A and it was possible to confirm that 95% was stored within 30A. This paper describes a method and validity of the load forecasting technology in the power distribution system.

Sano, Tsuneyo; Tezuka, Itsuko; Fukuda, Yoshihiro

314

PowerPACK: A wireless power distribution system for wearable devices  

Microsoft Academic Search

Motivated by the prevalence of small, battery-powered devices in many pervasive computing research and deployment scenarios, and the frustration encountered when a particular device is found to be useless due to a discharged internal battery, we present a backpack-worn wireless (non-contact) power distribution system. This system is designed to distribute power from a single point of generation or bulk storage

Travis Deyle; Matthew Reynolds

2008-01-01

315

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

Microsoft Academic Search

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

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

2010-01-01

316

Distributed Static Compensator with fuel cell for power quality improvement and hybrid power generation  

Microsoft Academic Search

This paper presents analysis and design of Distributed STATic COMpensator (DSTATCOM) with fuel cell utilized for power quality improvement and hybrid power generation. Factors affecting the performance and limitation of active and reactive power compensation are analyzed and presented in this paper. A boost converter circuit is selected to step up and regulate the fuel cell terminal voltage to match

Peerapon Chanhom; Siriroj Sirisukprasert

2009-01-01

317

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

Microsoft Academic Search

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

Pritam Das; Gerry Moschopoulos

2008-01-01

318

Fast Power-Up Active Link Protection in Autonomous Distributed Transmitter Power Control  

Microsoft Academic Search

In this work, we propose an enhancement to the DPC\\/ALP (distributed power control with active link protection) algorithm that allows fast power ramp-up without compromising the ALP guarantee. The original DPC algorithm was first augmented with ALP to provide absolute performance guarantees. The basis of active link protection lies on constraining the rate of the new links' transmission power increase

Savvas Gitzenis; Nicholas Bambos

2008-01-01

319

Quality monitoring of electrical power distribution network using a low-power microcontroller  

Microsoft Academic Search

This paper presents a system for monitoring the electrical disturbances which are present every day in electrical power distribution networks. A simple solution for detecting the disturbances using a low power microcontroller (MSP 430) was developed. The system was devised to work with 230 V 50 Hz electrical power networks in Europe.

C. Dughir; V. Groza; A. Vartosu; G. Prostean

2009-01-01

320

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

Microsoft Academic Search

DC microgrid is a novel power system using dc distribution in order to provide a super high quality electric power. The dc distribution system is suitable for dc output type distributed generations such as photovoltaic and fuel cells, and energy storages such as batteries and electric double layer capacitors. Power is distributed through dc distribution line and converted to required

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

2008-01-01

321

The reality of generation and distribution of electric power, Part 2: the other face of ultrahigh voltage power transmission  

Microsoft Academic Search

In this sequel, I examine power transmission and consider some of the equipment and instruments. Transmission equipment starts with towers, pylons, conductors, accessories, such as insulators, connectors, and splicers, and I discuss their importance. Special attention is given to the voltage limiting effects of corona discharges. The pros and contras of power transmission with alternating current (ac) and direct current

Alex Hebra

2012-01-01

322

A medium-voltage transformerless AC\\/DC power conversion system consisting of a diode rectifier and a shunt hybrid filter  

Microsoft Academic Search

This paper proposes a 3.3-kV transformerless AC-to-DC power conversion system consisting of a three-phase six-pulse diode rectifier and a shunt hybrid filter. The hybrid filter is formed by a single tuned LC filter per phase and a small-rated three-phase active filter, which are directly connected in series without any matching transformer. The required rating of the active filter is much

Sunt Srianthumrong; Hirofumi Akagi

2003-01-01

323

A medium-voltage transformerless AC\\/DC power conversion system consisting of a diode rectifier and a shunt hybrid filter  

Microsoft Academic Search

This paper proposes a 3.3-kV transformerless AC-to-DC power conversion system consisting of a three-phase six-pulse diode rectifier and a shunt hybrid filter. The hybrid filter is formed by a single tuned LC filter per phase and a small-rated three-phase active filter, which are directly connected in series without any matching transformer. The required rating of the active filter is much

Sunt Srianthumrong; Hirofumi Akagi

2002-01-01

324

Base\\/gate drive suppression of inactive power devices of a voltage-fed inverter and precision synthesis of AC voltage and DC link current waves  

Microsoft Academic Search

A control principle that suppresses the base\\/gate drive of inactive power semiconductor devices of a voltage-fed inverter that supplies lagging reactive load is described. The principle is utilized to fabricate precisely the inverter output AC voltage waves from the information of DC link voltage, base\\/gate drive logic waves, and estimated drops across the conducting devices. The estimation of DC link

Ravindra P. Joshi; Bimal K. Bose

1990-01-01

325

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

Microsoft Academic Search

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

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

2008-01-01

326

An improved automotive power distribution system using nonlinear resonant switch converters  

Microsoft Academic Search

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

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

1991-01-01

327

A Control Method of a Small-Scale DC Power System Including Distributed Generators  

NASA Astrophysics Data System (ADS)

This paper describes a dc micro-grid system interconnecting distributed power generators. The system consists of five generation and control units; a solar-cell generation unit, a wind-turbine generation unit, a battery energy-storage unit, a flywheel power-leveling unit, and an ac grid-interconnecting power control unit. The control method is proposed for suppressing the circulating current by detecting only the dc grid voltage. This method brings high reliability, high-flexibility and maintenance-free operation to the system. The method pays attention to dc output voltage performance of each unit. Each of the power control unit and the energy-storage unit is controlled to act as a voltage source with imaginery impedance. On the other hand, each of the two generation units is controlled to act as a current source. The power-leveling unit is controlled to act as a current source having the function of frequency selectivity like a high-pass filter. A 10-kW prototype system verifies experimentally the validity and effectiveness of the proposed control method for the dc-grid system.

Ito, Youichi; Yang, Zhongqing; Akagi, Hirofumi

328

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.

329

Probabilistic Vulnerability Assessment Based on Power Flow and Voltage Distribution  

SciTech Connect

Risk assessment of large scale power systems has been an important problem in power system reliability study. Probabilistic technique provides a powerful tool to solve the task. In this paper, we present the results of a study on probabilistic vulnerability assessment on WECC system. Cumulant based expansion method is applied to obtain the probabilistic distribution function (PDF) and cumulative distribution function (CDF) of power flows on transmission lines and voltage. Overall risk index based on the system vulnerability analysis is calculated using the WECC system. The simulation results based on WECC system is used to demonstrate the effectiveness of the method. The methodology can be applied to the risk analysis on large scale power systems.

Ma, Jian; Huang, Zhenyu; Wong, Pak C.; Ferryman, Thomas A.

2010-04-30

330

Modified Pulse-Adjustment Technique to Control DC\\/DC Converters Driving Variable Constant-Power Loads  

Microsoft Academic Search

Multiconverter-distributed DC architectures have been utilized for power distribution in many applications such as telecommunication systems, sea and undersea vehicles, an international space station, aircraft, electric vehicles, hybrid-electric vehicles, and fuel-cell vehicles, where reliability is of prime concern. The number of power-electronic converters (AC\\/DC, DC\\/DC, DC\\/AC, and AC\\/AC) in these multiconverter electrical power systems varies from a few converters in

Alireza Khaligh; Amir M. Rahimi; Ali Emadi

2008-01-01

331

Automation of the Athens (Tennessee) electric power distribution system  

SciTech Connect

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

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

1988-01-01

332

Physical Origin of the Power-Law Tailed Statistical Distributions  

NASA Astrophysics Data System (ADS)

Starting from the BBGKY hierarchy, describing the kinetics of nonlinear particle system, we obtain the relevant entropy and stationary distribution function. Subsequently, by employing the Lorentz transformations we propose the relativistic generalization of the exponential and logarithmic functions. The related particle distribution and entropy represents the relativistic extension of the classical Maxwell-Boltzmann distribution and of the Boltzmann entropy, respectively, and define the statistical mechanics presented in [Phys. Rev. E 66 (2002) 056125] and [Phys. Rev. E 72 (2005) 036108]. The achievements of the present effort, support the idea that the experimentally observed power-law tailed statistical distributions in plasma physics, are enforced by the relativistic microscopic particle dynamics.

Kaniadakis, G.

333

Forty-seventh annual power distribution conference, 1994  

SciTech Connect

This is a collection of papers presented at the forty-seventh annual Power Distribution Conference in 1994. The topics of the papers include recent developments in distribution grounding, partial discharge analysis of electrical machinery, insulating fluids analysis as a basis for a complete transformer monitoring program, environmental and regulatory issues regarding the use of silicone transformer fluids, locating and identifying harmonic sources, optimizing distribution operations resources, surface launch directional boring units, electrical supply to Dallas/Fort Worth international airport, a microprocessor-based digital feeder monitor with high-impedance fault detection, a modern review of distribution system protective coordination, and Ski Apache electric service improvements.

Not Available

1994-01-01

334

The Information System For Power Distribution System As Answer On New Demands In Power Distribution System  

Microsoft Academic Search

Information is most important thing now in 21st century. The many power utility company do not use information system for technical problems. This company work as before ten or fifty years. Only way for progress is insert information system into power utility system. Information system go into power utility company first as billing system. Next step is accounting, information system

S. M. Dragojlovic; O. T. Milenkovic; M. Vujicic

2005-01-01

335

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

336

Non-uniform spatial distributions of both the magnitude and phase of AC electric fields determine dielectrophoretic forces  

Microsoft Academic Search

It is well known that the conventional dielectrophoretic force acting on a polarised particle in a non-uniform AC electric field is proportional to the in-phase component of the induced dipole moment and the non-uniformity of the field strength. In contrast, the travelling-wave-dielectrophoretic force that acts on a particle subjected to a travelling electric field is proportional to the out-of-phase component

X.-B Wang; M. P Hughes; Y Huang; F. F Becker; P. R. C Gascoyne

1995-01-01

337

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

SciTech Connect

This report chronicles Utility Power Group's (UPG) successful two-year Photovoltaic Manufacturing Technology (PVMaT) Phase 4A1 work effort which began in July, 1995. During this period, UPG completed design, fabrication, testing and demonstration of a modular and fully integrated 15-kW-ac, solar tracking PV power system sub-array. The two key and innovative components which were developed are a Modular Panel which optimizes factory assembly of PV modules into a large area, field-deployable, structurally-integrated PV panel, and an Integrated Power Processing Unit which combines all dc and ac power collection, conversion and control functions within a single, field-deployable structurally-integrated electrical enclosure. These two key sub-array elements, when combined with a number of other electrical, mechanical, and structural components, create a low-cost and high-performance PV power system. This system, or sub-array, can be deployed in individual units, or paralleled with any number of other sub-arrays, to construct multi-megawatt P fields. 21 figs.

Stern, M.; Duran, G.; Fourer, G.; Mackamul, K.; Whalen, W.; Loo, M. van; West, R. [Utility Power Group, Chatsworth, CA (US)

1998-06-01

338

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

339

Subsystem design in aircraft power distribution systems using optimization  

NASA Astrophysics Data System (ADS)

The research reported in this dissertation focuses on the development of optimization tools for the design of subsystems in a modern aircraft power distribution system. The baseline power distribution system is built around a 270V DC bus. One of the distinguishing features of this power distribution system is the presence of regenerative power from the electrically driven flight control actuators and structurally integrated smart actuators back to the DC bus. The key electrical components of the power distribution system are bidirectional switching power converters, which convert, control and condition electrical power between the sources and the loads. The dissertation is divided into three parts. Part I deals with the formulation of an optimization problem for a sample system consisting of a regulated DC-DC buck converter preceded by an input filter. The individual subsystems are optimized first followed by the integrated optimization of the sample system. It is shown that the integrated optimization provides better results than that obtained by integrating the individually optimized systems. Part II presents a detailed study of piezoelectric actuators. This study includes modeling, optimization of the drive amplifier and the development of a current control law for piezoelectric actuators coupled to a simple mechanical structure. Linear and nonlinear methods to study subsystem interaction and stability are studied in Part III. A multivariable impedance ratio criterion applicable to three phase systems is proposed. Bifurcation methods are used to obtain global stability characteristics of interconnected systems. The application of a nonlinear design methodology, widely used in power systems, to incrementally improve the robustness of a system to Hopf bifurcation instability is discussed.

Chandrasekaran, Sriram

2000-10-01

340

Power law distribution of dividends in horse races  

NASA Astrophysics Data System (ADS)

We discovered that the distribution of dividends in Korean horse races follows a power law. A simple model of betting is proposed, which reproduces the observed distribution. The model provides a mechanism to arrive at the true underlying winning probabilities, which are initially unknown, in a self-organized collective fashion, through the dynamic process of betting. Numerical simulations yield excellent agreement with the empirical data.

Park, K.; Domany, E.

2001-02-01

341

A modified power flow calculation method for radial distribution system  

Microsoft Academic Search

Distribution power flow calculation is base of distribution system analysis. The characteristics and differences of Back\\/forward sweep method and Newton method are compared and analyzed, and a modified back\\/forward sweep method is proposed based on the conventional back\\/forward sweep method, in which the correction equation of node voltage in the back sweep process is just simply replaced by a new

Liu Wei; Ning Wen-hui; Huang Dong-shan

2008-01-01

342

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

SciTech Connect

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

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

2007-07-01

343

An AC Processing Pickup for IPT Systems  

Microsoft Academic Search

This paper presents a new type of inductive power transfer (IPT) pickup that directly regulates the power in ac form, hence producing a controllable high-frequency ac source suitable for lighting applications. The pickup has significant advantages in terms of increasing system efficiency, reducing pickup size, and lowering production cost compared to traditional pickups that also produce a controlled ac output

Hunter Hanzhuo Wu; John T. Boys; Grant Anthony Covic

2010-01-01

344

Calibration of Hall sensor AC loss measurements  

Microsoft Academic Search

Accurate measurements of the magnetic AC loss in short samples of conductor are essential for the design of superconducting power devices and guide the development of superconducting wire with low AC losses. The authors report quantitative AC loss measurements at power frequencies at 77 K obtained with a Hall sensor magnetometer (HSM) using a calibration method which involves assumptions about

M. Staines; S. Rupp; D. Caplin; D. Yu; S. Fleshler

2001-01-01

345

Design and control of Series DC Active Filter (SDAF) for shipboard Medium-Voltage DC power system  

Microsoft Academic Search

Shipboard power system (SPS) can have either ac or dc distribution systems, or a c ombination of both ac and dc distribution systems. However, the Navy has identified Medium- Voltage DC (MVDC) as a long-term solution for electric power distribution to meet the high pow er density requirements in future shipboard power systems. Thyristor bridges are a v iable front-end

Hesam Mirzaee; Babak Parkhideh; Subhashish Bhattacharya

2011-01-01

346

Wind Power Forecasting Error Distributions: An International Comparison; Preprint  

SciTech Connect

Wind power forecasting is expected to be an important enabler for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that do occur can be critical to system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.

Hodge, B. M.; Lew, D.; Milligan, M.; Holttinen, H.; Sillanpaa, S.; Gomez-Lazaro, E.; Scharff, R.; Soder, L.; Larsen, X. G.; Giebel, G.; Flynn, D.; Dobschinski, J.

2012-09-01

347

Load Frequency Control in Power System with Distributed Generation  

NASA Astrophysics Data System (ADS)

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

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

348

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.

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

2012-01-01

349

HEMP interaction with an electric power distribution circuit. Final report  

SciTech Connect

A high altitude nuclear burst, detonated at a height of 50 km or more, causes two types of electromagnetic pulses, high altitude EMP (HEMP) and magnetohydrodynamic EMP, which will interact with electric power systems. Previous work indicated that millions of miles of electric distribution systems in the United States may be especially vulnerable to HEMP incident simultaneously throughout large portions of the United States. Purpose of this work was to perform an initial assessment of HEMP induced surges on a simplified electric distribution system. This report presents the assumptions, methodology, and resulting induced transient voltages and currents at various points in the distribution circuit in the microsecond timeframe, considering the impacts of HEMP incident simultaneously throughout the distribution system for a range of parametric conditions. Results of this work suggest that EMP could induce voltage transients that far exceed the basic insulation level (BIL) of distribution systems and that a more detailed analysis is warranted.

Zaininger, H.W.; Jaszewski, G.M.

1985-08-01

350

High-Quality Power Generation Through Distributed Control of a Power Park Microgrid  

Microsoft Academic Search

Inverters are a necessary interface for several forms of distributed generation (DG) and where they form a microgrid they have the potential to offer high power quality. The challenge is to coordinate the actions of a group of inverters so that they offer the level of power quality known to be possible from fast local control of a single inverter.

M. Prodanovic; Timothy C. Green

2006-01-01

351

Grid Impedance Monitoring System for Distributed Power Generation Electronic Interfaces  

Microsoft Academic Search

This paper proposes a grid impedance monitoring system for distributed power generation electronic interfaces. The system estimates the grid equivalent impedance and voltage source from the voltage measurements performed at the point of common coupling. The estimation algorithm is based on a recursive least-squares algorithm implemented in the complex field. Simultaneously, the system evaluates the quality of the estimation, minimizing

Santiago Cobreces; Emilio J. Bueno; Daniel Pizarro; Francisco J. Rodriguez; Francisco Huerta

2009-01-01

352

CDMA based distribution power net automatization and data transmission system  

Microsoft Academic Search

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

Wang Hankang; Li Quancheng; Jiang Hai

2005-01-01

353

Power distribution modelling of high performance first level computer packages  

Microsoft Academic Search

A methodology for obtaining a model of the power distribution of a computer package is presented. This model is suitable for determining the noise and aiding in the design of a computer package. The physical features of a typical first-level multi-layered computer package is shown. Semiconductor chips and decoupling capacitors are placed on the top surface of the package and

W. Becker; B. McCredie; G. Wilkins; A. Iqbal

1993-01-01

354

Network Reconfiguration for Service Restoration in Shipboard Power Distribution Systems  

Microsoft Academic Search

The electric power systems of U.S. Navy ships supply energy to sophisticated systems for weapons, communications, navigation, and operation. Circuit breakers (CBs) and fuses are provided at different locations for isolation of faulted loads, generators, or distribution system from unfaulted portions of the system. These faults could be due to widespread system fault resulting from battle damage or material casualties

K. L. Butler; N. D. R. Sarma; V. Ragendra Prasad

2001-01-01

355

Network reconfiguration for service restoration in shipboard power distribution systems  

Microsoft Academic Search

Summary form only given, as follows. The electric power systems of US Navy ships supply energy to sophisticated systems for weapons, communications, navigation and operation. Circuit breakers (CBs) and fuses are provided at different locations for isolation of faulted loads, generators or distribution system from unfaulted portions of the system. These faults could be due to widespread system faults resulting

K. L. Butler; N. D. R. Sarma; V. Ragendra Prasad

2002-01-01

356

Network reconfiguration for service restoration in shipboard power distribution systems  

Microsoft Academic Search

The electric power systems of US Navy ships supply energy to sophisticated systems for weapons, communications, navigation and operation. Circuit breakers (CBs) and fuses are provided at different locations for isolation of faulted loads, generators or distribution system from unfaulted portions of the system. These faults could be due to widespread system fault resulting from battle damage or material casualties

Karen L. Butler; N. D. R. Sarma; V. Ragendra Prasad

2001-01-01

357

HEMP interaction with an electric power distribution circuit. Final report  

Microsoft Academic Search

A high altitude nuclear burst, detonated at a height of 50 km or more, causes two types of electromagnetic pulses, high altitude EMP (HEMP) and magnetohydrodynamic EMP, which will interact with electric power systems. Previous work indicated that millions of miles of electric distribution systems in the United States may be especially vulnerable to HEMP incident simultaneously throughout large portions

H. W. Zaininger; G. M. Jaszewski

1985-01-01

358

Raptor electrocutions-emerging issues [overhead power distribution  

Microsoft Academic Search

The electrocution of raptors and larger perching birds is a hazard of overhead distribution construction, especially in the Western United States where poles in treeless areas make attractive perches. Disturbed by the continuing large numbers of raptors, particularly eagles, electrocuted along power lines, the US Fish and Wildlife (SFWS) has begun to step up enforcement of the Migratory Bird Treaty

Richard E. Harness

2000-01-01

359

A robust power flow algorithm for radial distribution systems  

Microsoft Academic Search

In this paper, a new algorithm is presented to solve the power flow problem in radial distribution systems. The proposed method takes into account the voltage dependency of static loads, and line charging capacitance. The method is based on the forward and backward voltage calculation by using polynomial voltage equation and KirchofPs Law for each branch. Convergence speed and reliability

U. Eminoglu; M. H. Hocaoglu

2005-01-01

360

Application of continuation power flow method in radial distribution systems  

Microsoft Academic Search

The paper presents a set of equations (SOE) comprising voltage magnitude and nodal real\\/reactive power balance equations to model a radial distribution system (RDS). The voltage equations in the SOE have dual roots. Then a Newton–Raphson (NR) method is presented to solve the SOE to determine the voltage solution of an RDS. This NR method is extended using the continuation

A. Dukpa; B. Venkatesh; M. El-Hawary

2009-01-01

361

Impacts of electric vehicle loads on power distribution systems  

Microsoft Academic Search

Electric vehicles (EVs) are the most promising alternative to replace a significant amount of gasoline vehicles to provide cleaner, CO2 free and climate friendly transportation. On integrating more electric vehicles, the electric utilities must analyse the related impacts on the electricity system operation. This paper investigates the effects on the key power distribution system parameters like voltages, line drops, system

Jayakrishnan R. Pillai; Birgitte Bak-Jensen

2010-01-01

362

Pointers and linked lists in electric power distribution circuit analysis  

Microsoft Academic Search

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

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

1991-01-01

363

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

Microsoft Academic Search

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

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

2002-01-01

364

Electron beam machining using rotating and shaped beam power distribution  

DOEpatents

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

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

1996-01-01

365

Electron beam machining using rotating and shaped beam power distribution  

DOEpatents

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

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

1996-07-09

366

An Approach to a Higher-Power-Density Power Supply for 380-V DC Distribution System  

NASA Astrophysics Data System (ADS)

A methodology for realizing a higher-power-density DC-DC converter has been proposed for a power unit installed in a 380-V DC distribution system. The possibility of the converter design will be strengthened by using the series-parallel connection topology for isolated DC-DC converters. A converter prototype with a power density of 10W/cm3 has been fabricated, and the feasibility of the converter design has been confirmed experimentally. This result contributes to the realization of a highly efficient and highly space-saving 380-V DC distribution system.

Hayashi, Yusuke; Mino, Masato

367

Analysis of a Microturbine Generator System Connected to a Distribution System Through Power-Electronics Converters  

Microsoft Academic Search

This paper presents the analyzed results of a per- manent-magnet synchronous generator-based microturbine generator (MTG) system connected to a distribution system through an AC-to-DC converter and a DC-to-AC inverter. The employed mathematical model based on a -axis reference frame is derived to establish the complete dynamic equations of the studied MTG system for simulating the characteristics of the MTG under

Li Wang; Guang-Zhe Zheng

2011-01-01

368

AC induction motor efficiency  

Microsoft Academic Search

The author discusses those factors which determine the efficiency and rating of polyphase AC induction motors. The loss mechanisms are described and are related to the performance and design characteristics of the motor, such as the operating flux density, the winding turns distribution, the current density in the windings, the motor speed torque characteristic, and the motor efficiency itself. The

S. D. Umans

1989-01-01

369

Distributed software architecture of PEBB-based plug and play power electronics systems  

Microsoft Academic Search

A novel hierarchical software architecture, based on power electronics building blocks (PEBB) concept, is proposed to build flexible, configurable and reusable power electronics system control software. Some important issues about software design are addressed. And as an example, a three-phase DC-AC inverter is implemented under this hierarchical architecture

Jinghong Guo; Ivan Celanovic; Dushan Borojevic

2001-01-01

370

Distributed generation modeling for power flow studies and a three-phase unbalanced power flow solution for radial distribution systems considering distributed generation  

Microsoft Academic Search

Distributed generations (DGs) are generally modeled as PV or PQ nodes in power flow studies (PFSs) for distribution system. Determining a suitable model for each DG unit requires knowing the DG operation and the type of its connection to the grid (direct or indirect). In this respect, this paper offers a helpful list of DG models for PFSs. Moreover, an

S. M. Moghaddas-Tafreshi; Elahe Mashhour

2009-01-01

371

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

372

Application of Genetic Algorithm for the Reduction of Reactive Power Losses in Radial Distribution System  

Microsoft Academic Search

Power losses in distribution system have become the most concerned issue in power losses analysis in any power system. In the effort of reducing power losses within distribution system, reactive power compensation has become increasingly important as it affects the operational, economical and quality of service for electric power systems. This paper presents the application of genetic algorithm approach for

Perumal Nallagownden; L. T. Thin; N. C. Guan; C. M. H. Mahmud

2006-01-01

373

Large Signal Stability Analysis of 'More Electric' Aircraft Power Systems with Constant Power Loads  

Microsoft Academic Search

This paper presents a detailed analysis of the dynamic behaviour of a hybrid ac-dc electric power system under large disturbances. The system under study is representative of a power distribution network which is currently being developed for future \\

Antonio Griffo; Jiabin Wang

2012-01-01

374

Dynamic voltage regulation and power export in a distribution system using distributed generation  

Microsoft Academic Search

The major aim of power quality (PQ) enhancing techniques is to maintain a specified voltage magnitude at a desired frequency\\u000a for sensitive loads irrespective of faults on the power distribution network. The dynamic voltage restorer (DVR) is a device\\u000a used to mitigate voltage sags to regulate load voltage. This paper presents a mathematical model for leading series voltage\\u000a injection to

Aamir Hanif; Muhammad Ahmed Choudhry

2009-01-01

375

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

376

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

377

Power distribution for an Am/Cm bushing melter  

SciTech Connect

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

Gong, C.; Hardy, B.J.

1996-12-31

378

Reliability and cost comparison of power distribution configurations  

Microsoft Academic Search

Reliability and installed cost are key parameters in the selection of the appropriate power system distribution design. This paper presents a relative comparison of reliability and costs for radial, primary selective, looped, main-tie-main, synchronous bus, ring bus, and double bus medium voltage configurations. It also examines radial, main-tie-main and spot network for low voltage. To simplify the analysis, the alternate

V. E. Wagner

2008-01-01

379

Application of geographic information system in distribution power network automation  

NASA Astrophysics Data System (ADS)

Geographic information system (GIS) is the computer system in support of computer software with collection, storage, management, retrieval and comprehensive analysis of a variety of geospatial information, with various forms output data and graphics products. This paper introduced GIS data organization and its main applications in distribution power network automation, including both offline and online, and proposed component-based system development model and the need to establish WEBGIS and reliability.

Wei, Xianmin

2011-01-01

380

UPDATION OF ECR POWER SUPPLY CONTROLS TO DISTRIBUTED PC ENVIRONMENT  

Microsoft Academic Search

Controls of the ECR source and the beam-handling elements for injection of the heavy ions into the cyclotron, are being shifted to the central control room, in phases. The work constitutes a part of the retro-fitted distributed computerization of the Cyclotron. A Pentium, Win95 PC working in the ECR front-end takes care of the above power supplies controls. Existing CAMAC

Tushar K. Das; Amitava Roy; Sushanta K. Pal; S. Dasgupta

381

Control of power electronic interfaces in distributed generation microgrids  

Microsoft Academic Search

Technological advances and environmental pressures are driving the interconnection of renewable energy sources to the distribution network. The interconnection of large amounts of non-traditional generation however causes problems in a network designed for ‘conventional’ operation. The use of power electronics interfaces and the ‘bundling’ of micro-generation and loads into so-called Microgrids, offers a potential solution. Each Microgrid is designed to

A. Arulampalam; M. Barnes; A. Engler; A. Goodwin; N. Jenkins

2004-01-01

382

Validating theoretical hypothesis on access times and repair times statistical distributions for electric power distribution network  

Microsoft Academic Search

Data of interruptions of electric supply in electric power distribution networks and faults of their components were collected by utility company Iberdrola from several Spanish regions. After correcting and mixing these general data for building the histograms of the variables “times to access the faults” and “times to repair” for all data, it can be shown that these two histograms

M. V. Riesco; F. A. Frchoso; P. C. Alvarez; A. Gordaliza

1996-01-01

383

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

384

Inverse Power Law distribution and failure initiation of subaerial landslides  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

385

CRE2: A CP Application for Reconfiguring a Power Distribution Network for Power Losses Reduction  

Microsoft Academic Search

\\u000a CRE2 is a CP application written in MOzArt (www.mozart-oz.org) for reconfiguring power distribution networks for power losses reduction. This includes two distinct interacting processes:\\u000a load flow computation and selecting switches to open or close. Load flow is computed for each radial network obtained from switching operations. We developed a real intervals constraint system (XRI) and integrated it to MOzArt. CRE2

Juan Francisco Díaz; Gustavo Gutierrez; Carlos Alberto Olarte; Camilo Rueda

2004-01-01

386

Automation of the Athens (Tennessee) electric power distribution system  

SciTech Connect

In an effort to provide electricity at a minimum cost, the electric utility industry continues to examine methods to operate generating plants, transmission lines, distribution equipment, and customer appliances more efficiently. The Athens Automation and Control Experiment (AACE) was conceived and implemented to address these needs. Located on the Athens Utilities Board system in Athens, Tennessee, the AACE is a highly instrumented system serving a closely surveyed group of 2000 consumers. AACE was designed as a test for distribution automation and control experiments. Observation of the results from the experiments will help to show which controls are worthwhile, what data and instrumentation are needed, and which monitoring and control functions for distribution systems are justified. Testing of the new automated system began in the fall of 1985, and the results may have a dramatic impact on the way electric power systems will be designed and operated in the future. Results from volt/var, system reconfiguration, and load control experiments are described.

Gnadt, P.A.

1987-01-01

387

A Power Flow Method for Radial and Meshed Distribution Systems Including Distributed Generation and Step Voltage Regulator Modeling  

Microsoft Academic Search

This paper proposes a new power flow method for radial and meshed distribution systems. The method convert a meshed distribution system with distributed generators into an equivalent single source radial distribution system, by breaking out the tie lines and distributed generators con- nections, and by abstracting auxiliary buses to the distri- bution network. The approach goes beyond the previous works

Diego Issicaba; J. Coelho

2007-01-01

388

Distribution of 1298A>C polymorphism of methylenetetrahydrofolate reductase gene in patients with bipolar disorder and schizophrenia.  

PubMed

We investigated the genotype frequency of methylenetetrahydrofolate reductase (MTHFR) 1298A>C polymorphism in the group of patients with bipolar disorder type I (BDI) (n=200) and schizophrenia (n=200) and in the control group (n=300). Odds ratio (OR) for patients with BD and schizophrenia in 1298CC homozygous state was 3.768 (95% CI=1.752-8.104); P=0.0003; (P=0.0006 after Bonferroni correction) and 2.694; (95% CI=1.207-6.013); P=0.0123 (P=0.0246 after Bonferroni correction), respectively. The stratification of patients based on gender revealed significant association of 1298CC genotype with female patients only with BDI (OR=7.293; 95% CI=2.017-26.363; P=0.0005). Our results confirm association of BD and schizophrenia with the 1p36.3 MTHFR locus and with the methyl group transfer using folate-dependent one-carbon pathway. PMID:17188847

Kempisty, Bartosz; Bober, Anna; ?uczak, Marta; Czerski, Piotr; Szczepankiewicz, Aleksandra; Hauser, Joanna; Jagodzi?ski, Pawe? P

2006-12-26

389

Electrical power distribution system based on 1553B bus for advanced aircraft  

Microsoft Academic Search

A novel aeronautical electrical power distribution system based on 1553B bus is proposed in this paper with the analysis of aircraft electrical power distribution system structure. First, several control schemes such as CCS (centralized control system) are researched and the benefit of DCS (distributed control system) configuration is analyzed. Then according to the control flow of aircraft electrical power distribution

Fu Dafeng; Xing Yan; Yang Shanshui; Yan Yangguang

2005-01-01

390

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

National Technical Information Service (NTIS)

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 generati...

B. H. Chowdhury

2005-01-01

391

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

392

Harmonic analysis of multi-phase electric-power distribution systems  

SciTech Connect

This study presents a computer program as a tool for the harmonic analysis of multi-phase electric power distribution systems. In the program, the source of harmonics can be any number of multi-phase harmonic currents and/or voltages, or up to 10 three-phase converts. Frequency-dependent models of ac network elements are assembled into a sparse admittance matrix. Then, sparsity techniques are employed to determine the current flow in all elements and voltages at all busses throughout the system at any harmonic frequency up to 3 KHz. Voltage distortion factors that represent the overall effects of the harmonics of the system voltages are also calculated. The digital program was then applied to a multi-phase distribution system in order to observe the response of the system to the various changes that were made in the system. It was found that the converter size and location, the capacitor bank sizes and locations, and the representation of the system loads are factors in determining in harmonic current flows and the level of voltage-distortion factors. Also, the response of the system to single-phase harmonic sources was investigated, and it was discovered that the effects of single-phase harmonic sources can be serious enough that they should not be ignored in the harmonic analysis of multi-phase systems.

Hosseini, S.H.

1988-01-01

393

Mill motors for adjustable speed AC drives  

Microsoft Academic Search

AC adjustable speed drives are being considered for many rolling mill applications. The author describes AC motor characteristics, and how they relate to adjustable speed mill drives. Included is a review of AC motor theory highlighting distinctions between induction and synchronous machines along with comparisons to DC motor performance. Constant power speed range performance and limitations, damper winding requirements, and

William J. Jackson

1991-01-01

394

Dynamic analysis of start-up strategies of AC excited Double Fed Induction Machine for pumped storage power plant  

Microsoft Academic Search

The electric power generation using hydro potential is increasing around the globe due to many reasons like increasing power demand, deregulated markets, and environmental concerns etc. At the same time, extended transmission networks, higher degrees of interconnection between different networks, and fast connection and disconnection of the heavy loads demand flexible, fast power generation and consumption to and from the

Rajesh Saiju; Jiri Koutnik; Klaus Krueger

2009-01-01

395

Power Consumption Evaluation of Distributed Computing Network Considering Traffic Locality  

NASA Astrophysics Data System (ADS)

When computing resources are consolidated in a few huge data centers, a massive amount of data is transferred to each data center over a wide area network (WAN). This results in increased power consumption in the WAN. A distributed computing network (DCN), such as a content delivery network, can reduce the traffic from/to the data center, thereby decreasing the power consumed in the WAN. In this paper, we focus on the energy-saving aspect of the DCN and evaluate its effectiveness, especially considering traffic locality, i.e., the amount of traffic related to the geographical vicinity. We first formulate the problem of optimizing the DCN power consumption and describe the DCN in detail. Then, numerical evaluations show that, when there is strong traffic locality and the router has ideal energy proportionality, the system's power consumption is reduced to about 50% of the power consumed in the case where a DCN is not used; moreover, this advantage becomes even larger (up to about 30%) when the data center is located farthest from the center of the network topology.

Ogawa, Yukio; Hasegawa, Go; Murata, Masayuki

396

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

397

Minimizing power systems distribution losses using direct load control  

NASA Astrophysics Data System (ADS)

A recent study indicates that up to 13% of the total power generation is wasted in the form of losses in the distribution system. Network reconfiguration, capacitor installation, and reconductering have been used to reduce these losses. A new approach using Direct Load Control (DLC) of residential electric water heaters is proposed in this dissertation to minimize distribution system losses. When the power supply to water heaters is disconnected, the load drop per water heater equals its diversified demand at the time of load shed. When the interrupted loads are turned back on, the payback demand could be several times greater than the amount shed. One possible way to eliminate the detrimental effects of payback demand is to increase the storage capacity of the water heaters under DLC by adding a second water heater to an existing one or by, installing a single tank with sufficiently large volume. These additional storage devices are turned on during low load hours only and they store enough hot water to last during peak loads when the primary water heaters are disconnected. An optimization algorithm based on the Lagrange Multiplier method has been developed to minimize the power systems distribution losses and their associated costs. The objective function is given in terms of the peak power loss cost, annual energy loss cost, and the cost of the DLC program. The objective function is solved to obtain the optimal number and location of water heaters under DLC. The proposed methodology has been tested using two distribution system main feeders: a typical main feeder and a high loss feeder. The feeders were tested with and without laterals. Results show that the peak power loss has been reduced by 25.26% and 25.95% in the typical main feeder and by 27.34% and 28.17% in the high loss feeder. The annual energy loss was reduced by 1.94% and 1.96% in the typical feeder and by 2.20% and 2.26% in the high loss feeder. The feeders annual cost were reduced moderately (3.85% to 7.08%). The proposed methodology has also improved the losses and the generation costs in the transmission system.

Wehbe, Ali M.

398

From Lognormal Distribution to Power Law:. a New Classification of the Size Distributions  

NASA Astrophysics Data System (ADS)

We propose a new classification of the size distributions of entities based on an exponent ? defined from the shape of the log-log Rank Size plot. From an inspection of a large number of cases in different fields, one finds three possibilities: ? = 1 giving a power law, ? > 1 (parabola like curve) and 0 < ? < 1 (analogous to a log normal distribution). A fourth possibility that can be defined when ? < 0 was never observed. We present a modified version of models based on a random multiplicative process and an introduction of new entities during the growth. We recover all three kinds of distributions and show that the type of a distribution is conditioned by the rate of the introduction of new entities.

Benguigui, Lucien; Blumenfeld-Lieberthal, Efrat

399

Intraluminal ultrasound intensity distribution and backscattered Doppler power.  

PubMed

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

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

2004-11-01

400

Distribution of power output when establishing a breakaway in cycling.  

PubMed

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

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

2013-03-22

401

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

402

Power-law distributions from additive preferential redistributions  

NASA Astrophysics Data System (ADS)

We introduce a nongrowth model that generates the power-law distribution with the Zipf exponent. There are N elements, each of which is characterized by a quantity, and at each time step these quantities are redistributed through binary random interactions with a simple additive preferential rule, while the sum of quantities is conserved. The situation described by this model is similar to those of closed N -particle systems when conservative two-body collisions are only allowed. We obtain stationary distributions of these quantities both analytically and numerically while varying parameters of the model, and find that the model exhibits the scaling behavior for some parameter ranges. Unlike well-known growth models, this alternative mechanism generates the power-law distribution when the growth is not expected and the dynamics of the system is based on interactions between elements. This model can be applied to some examples such as personal wealths, city sizes, and the generation of scale-free networks when only rewiring is allowed.

Ree, Suhan

2006-02-01

403

Tomographic determination of the power distribution in electron beams  

DOEpatents

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

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

1996-12-10

404

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

405

Tomographic determination of the power distribution in electron beams  

DOEpatents

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

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

1996-01-01

406

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

Microsoft Academic Search

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

A. Martin Wildberger

1997-01-01

407

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

408

Influence of harmonics on power distribution system protection  

SciTech Connect

The effects of nonsinusoidal voltages and currents on the performance of static underfrequency and overcurrent relays were experimentally studied. The tests were conducted such that the frequency, amplitude and phase shift of individual harmonics could be adjusted in a controlled manner by employing a waveform generator with a phase-locking circuit. The relation between the harmonic currents and voltages was modelled through the power system impedances within residential distribution systems. It was found that for harmonic voltage and current amplitudes, as they occur in distribution systems, underfrequency relays and the time delay operation of overcurrent relays show a marked deterioration in their performance. The instantaneous operating characteristics of overcurrent relays, however, are hardly affected by the presence of harmonic currents.

Fuller, J.F.; Fuchs, E.F.; Roesler, D.J.

1988-04-01

409

Using SMES as a multi-purpose interface in power generation, transmission and distribution systems  

Microsoft Academic Search

The objectives are to introduce the concept of the multiterminal superconductive magnetic energy storage (MSMES) scheme and to show that new SMES applications and more SMES benefits to electric power systems can be realized by using MSMES. The authors show a schematic diagram of the conventional SMES system. The SMES magnet is charged and discharged through one dc\\/ac converter terminal

Kwa-Sur Tam; X. Zhang; A. Yarali

1991-01-01

410

Dielectric properties and spatial distribution of polarization in polyethylene aged under ac voltage in a humid atmosphere  

Microsoft Academic Search

This paper reports the results of an investigation of the dielectric properties, growth of water tree density and spatial distribution of polarization in samples of non-stabilized LDPE. Samples were initially sand-blasted to accelerate initiation of water trees, and subsequently aged in salt solution for approximately three weeks under two regimes of temperature (room temperature and 65°C). Aging both with and

M. Wubbenhorst; J. Hornsby; M. Stachen; D. K. Das-Gupta; A. Bulinski; S. Bamji

1998-01-01

411

Characterization of Stand Alone AC Generators during No-Break Power Transfer using AI-EM Based Approach  

Microsoft Academic Search

This paper describes the use of artificial intelligence, - electromagnetic, AI-EM modeling approach for the performance prediction of stand alone synchronous generators during power transfer. This approach uses radial basis function, RBF, based data mining algorithm to evaluate the stresses accompanying the no break power transfer, NBPT. This mode of operation may result in the failure of the diodes in

A. A. Arkadan; N. Al Aawar; Y. Abou-Samra

2006-01-01

412

Automated fault location and diagnosis on electric power distribution feeders  

SciTech Connect

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

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

1997-04-01

413

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

SciTech Connect

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

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

2012-09-30

414

Dynamic model of a microturbine used as a distributed generator  

Microsoft Academic Search

In this paper, a dynamic model of a microturbine, used as distributed generator, is developed. The model is suitable for transient analysis and simulation of an unbalanced three-phase power system. A microturbine unit consists of four parts: a gas turbine engine, a permanent magnet generator, a three-phase bridge AC to DC rectifier, and a power DC to AC inverter. The

Amer Al-Hinai; Ali Feliachi

2002-01-01

415

System-level power optimization for real-time distributed embedded systems  

Microsoft Academic Search

Power optimization is one of the crucial design considerations for modern electronic systems. In this thesis, we present several system-level power optimization techniques for real-time distributed embedded systems, based on dynamic voltage scaling, dynamic power management, and management of peak power and variance of the power profile. Dynamic voltage scaling has been widely acknowledged as an important and powerful technique

Jiong Luo

2003-01-01

416

Improvement of a power quality of microgrid system interconnected to distribution system in emergency condition  

Microsoft Academic Search

In today's world, according as interest about renewable energy source rises, many researches are progressing about energy source development and power distribution system configuration for improving renewable energy source's efficiency. The microgrid is small power system that consists of several consumer's loads and small size distributed resources and accomplishes one independent system. It is operated by interconnecting with power distribution

T. Y. Jyung; Y. S. Baek; Y. G. Kim

2009-01-01

417

Impact of smart grids and green power generation on distribution systems  

Microsoft Academic Search

A significant amount of green power is being installed at the distribution level through the installation of green power generation facilities in the United States and Canada. This paper discusses green power generating sources (of 10 MW or less), which are connected to the utility system at the distribution level, and their impact on the distribution system. The paper also

Charles J. Mozina

2012-01-01

418

Impact of smart grid and green power generation on distribution systems  

Microsoft Academic Search

A significant amount of green power is being installed at the distribution level through the installation of green power generation facilities in the United States and Canada. This paper discusses green power generating sources (of 10 MW or less), which are connected to the utility system at the distribution level, and their impact on distribution system. The paper outlines the

Charles J. Mozina

2012-01-01

419

Characterization of broadband Monolithic Gallium Nitride distributed power amplifier using thermal imaging technique  

Microsoft Academic Search

A thermal imaging technique is used to characterize a Monolithic Gallium Nitride distributed power amplifier under DC and RF drive conditions. The temperature difference among the active cells (transistors) in distributed power amplifier is observed under RF drive conditions. It is believed that this non-uniform performance of individual cells in broadband distributed power amplifier results in its lower efficiency and

Chenggang Xie; Cedar Rapids

2011-01-01

420

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

Microsoft Academic Search

Renewable energy technologies such as photovoltaic, solar thermal electricity, and wind turbine power are environmentally beneficial sources of electric power generation. The integration of renewable energy sources into electric power distribution systems can provide additional economic benefits because of a reduction in the losses associated with transmission and distribution lines. Benefits associated with the deferment of transmission and distribution investment

P. R. Barnes; J. W. Vandyke; F. M. Tesche; H. W. Zaininger

1994-01-01

421

Single-phase power distribution system power flow and fault analysis  

NASA Astrophysics Data System (ADS)

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.

1992-10-01

422

Short circuit and collapsing bus voltage analysis of vital instrumentation and control power supply distribution in nuclear power generating stations  

Microsoft Academic Search

It is a common practice to utilize regulated power supplies in Vital Instrumentation and Control Power Systems (VICPS) to meet the requirements of IEEE Std. 308 in nuclear power generating stations. Most of these power supplies have current limiting features. Consequently, for a short circuit in a distribution system feeder, it is necessary to factor the performance characteristics of the

R. V. Rebbapragada; K. Saracinello

1994-01-01

423

Fuel cycle comparison of distributed power generation technologies.  

SciTech Connect

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

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

2008-12-08

424

An efficient three-phase power flow algorithm for distribution system including PV nodes  

Microsoft Academic Search

The power flow methods used in traditional distribution system will not meet the requirements of distributed generation systems. This paper presents a novel unbalanced three-phase power flow algorithm which fully exploited the special topological structure of radial distribution systems with distributed generation. On the basis of the bath matrix, the sensitivity incident matrix of node voltages and injection currents can

Li Hong-wei; Wang Hong-cheng; Xu Heng-jiao; M. A. Hai-bin

2011-01-01

425

A high-frequency, low volume, point-of-load power supply for distributed power systems  

Microsoft Academic Search

A resonant version of the DC-DC forward converter is presented in which both the primary-side switch and the secondary-side diode are either on or off at the same time. Such a topology is capable of operation in the 10-MHz range, and can be used for very-low volume point-of-load conversion in distributed power systems. This type of converter takes advantage of

LEO F. CASEY; MARTIN F. SCHLECHT

1988-01-01

426

Reactive power compensation and load balancing in electric power distribution systems  

Microsoft Academic Search

This article presents a new method for reactive power compensation and load balancing in a four-wire, three-phase distribution system. An IGBT-based PWM voltage source inverter with a dc bus capacitor is used as a compensator. The hysteresis-based carrierless PWM current control is employed to derive switching signals to the devices of the compensator. A detailed dynamic model of the complete

Bhim Singh; Ambrish Chandra; Kamal Al-Haddad; Anuradha; D. P. Kothari

1998-01-01

427

Tapped inductor filter-assisted soft-switching PWM DC-DC power converter with high frequency transformer link for automotive AC power supply  

Microsoft Academic Search

This paper presents a novel voltage source full-bridge type soft-switching phase-shift PWM controlled DC-DC power converter with a high frequency transformer link, which can operate under ZVS transition of leading bridge leg and ZCS transition of lagging bridge leg. This power converter can be used as power conditioner for small-scale solar photovoltaic cell and fuel cell power generation systems and

Serguei Moisseev; Y. Ishigami; K. Soshin; M. Nakaoka

2004-01-01

428

Vertical motion of a charged colloidal particle near an AC polarized electrode with a nonuniform potential distribution: theory and experimental evidence.  

PubMed

Electroosmotic flow in the vicinity of a colloidal particle suspended over an electrode accounts for observed changes in the average height of the particle when the electrode passes alternating current at 100 Hz. The main findings are (1) electroosmotic flow provides sufficient force to move the particle and (2) a phase shift between the purely electrical force on the particle and the particle's motion provides evidence of an E2 force acting on the particle. The electroosmotic force in this case arises from the boundary condition applied when faradaic reactions occur on the electrode. The presence of a potential-dependent electrode reaction moves the likely distribution of electrical current at the electrode surface toward uniform current density around the particle. In the presence of a particle the uniform current density is associated with a nonuniform potential; thus, the electric field around the particle has a nonzero radial component along the electrode surface, which interacts with unbalanced charge in the diffuse double layer on the electrode to create a flow pattern and impose an electroosmotic-flow-based force on the particle. Numerical solutions are presented for these additional height-dependent forces on the particle as a function of the current distribution on the electrode and for the time-dependent probability density of a charged colloidal particle near a planar electrode with a nonuniform electrical potential boundary condition. The electrical potential distribution on the electrode, combined with a phase difference between the electric field in solution and the electrode potential, can account for the experimentally observed motion of particles in ac electric fields in the frequency range from approximately 10 to 200 Hz. PMID:15984238

Fagan, Jeffrey A; Sides, Paul J; Prieve, Dennis C

2004-06-01

429

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

Microsoft Academic Search

Application of a dispersed power supply system combined with a large scale photovoltaic system (PV), a fuel cell (FC) and an electric double layer capacitor (EDLC) is studied in this paper. This system is operated in autonomous mode, taking account of time delay characteristics of FC. The modified Euler type Moving Average Prediction (EMAP) model is improved using short time

Koichi Hidese; Ichiro Takano; Hisao Nishikawa; Yoshio Sawada

2005-01-01

430

A high-powered A.C. plasma torch for the arc heating of molten steel in the tundish  

Microsoft Academic Search

Current user's requirements for excellent product quality means that producers must discover the isothermal casting conditions which trill lead to top operating performance in the continuous casting process. In response to this requirement. a high-powered A. C. plasma arc heating system was adopted for the No. 4 Continuous Caster (No. 4CC) put into operation at Kakogawa Works. This heating system

Hideaki Fujimoto; Hirohiko Tokunaga; Hideki Iritani

1994-01-01

431

Increase of Efficiency of an AC-DC Power Factor Correction Boost Converter by a Novel Soft-switching Technique  

Microsoft Academic Search

A novel implementation of a high power factor boost converter with increased efficiency is described. In this converter, a new zero-voltage transition technique is used for soft switching of the main and auxiliary switches; also, no additional voltage and current stresses on the main and auxiliary switches occur. The operating modes, theoretical analysis, and design considerations of the proposed converter

M. Mahesh; A. K. Panda

2011-01-01

432

Ac Indirect Line Conditioner Digital Control Using PLL Based on the Three-Phase Instantaneous Power Theory  

Microsoft Academic Search

This article presents the study of an alternating voltage indirect conditioner, showing the main aspects of its digital and analog control. The generation of the sinusoidal reference for the output voltage control loop is discussed, both in analog and digital control, and for that purpose, a digital PLL based on the three-phase instantaneous power theory is proposed. On the analog

C. E. M. Gomes; C. A. Petry; S. A. Mussa; H. B. Mohr

2006-01-01

433

A distributed power market for the Smart Grid  

NASA Astrophysics Data System (ADS)

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

McCulloch, Ryan James

434

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

435

Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation  

SciTech Connect

This report summarizes the work performed by Honeywell during the January 2002 to March 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. For this reporting period the following activities have been carried out: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} System-level performance model was created {lg_bullet} Dynamic control models are being developed {lg_bullet} Mechanical properties of candidate heat exchanger materials were investigated {lg_bullet} SOFC performance mapping as a function of flow rate and pressure was completed

Nguyen Minh

2002-03-31

436

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

437

Advanced distribution, switching, and conversion technology for fluids\\/combustion facility electric power control  

Microsoft Academic Search

The Electrical Power Control Unit (EPCU) under development for use in the Fluids\\/Combustion Facility (FCF) on International Space Station (ISS) is the precursor of modular power distribution and conversion concepts for future high power and small spacecraft applications. The EPCU is built from modular, current limiting Flexible Remote Power Controllers (FRPCs) and paralleled power converters packaged into a common orbital

Mark D. Poljak; James V. Soltis; David A. Fox

1997-01-01

438

MHD-EMP interaction with power transmission and distribution systems  

SciTech Connect

A nuclear detonation at altitudes of several hundred kilometers above the earth will distort the earth`s magnetic field and results in a time-variation of the geomagnetic field on the earth`s surface. This magnetic field interacts with the finitely conducting earth to produce a time varying electric field, also on the earth`s surface. Known at the magnetohydrodynamic electromagnetic pulse (MHD-EMP), this resulting E-field can induce a net voltage in long electrical conductors, such as power transmission lines. If these conductors are electrically connected to the earth at both ends, a current can be induced to flow in the conductors, and this can cause damage or upset to certain electrical systems. This paper presents the results of a study on the interaction of the MHD-EMP with power transmission and distribution (T&D) systems. A brief overview of the MHD-EMP environment used in the study is presented, and the analytical models used for estimating the coupling of this environment to T&D lines are discussed. Because of the quasi-static nature of MHD-EMP, the models are essentially simple DC circuit models. However, complications arise in attempting to treat realistic line configurations having a large number of support towers and an overhead shield or neutral wires. There models are discussed in detail. 3 refs., 5 figs., 1 tab.

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

1991-12-01

439

MHD-EMP interaction with power transmission and distribution systems  

SciTech Connect

A nuclear detonation at altitudes of several hundred kilometers above the earth will distort the earth's magnetic field and results in a time-variation of the geomagnetic field on the earth's surface. This magnetic field interacts with the finitely conducting earth to produce a time varying electric field, also on the earth's surface. Known at the magnetohydrodynamic electromagnetic pulse (MHD-EMP), this resulting E-field can induce a net voltage in long electrical conductors, such as power transmission lines. If these conductors are electrically connected to the earth at both ends, a current can be induced to flow in the conductors, and this can cause damage or upset to certain electrical systems. This paper presents the results of a study on the interaction of the MHD-EMP with power transmission and distribution (T D) systems. A brief overview of the MHD-EMP environment used in the study is presented, and the analytical models used for estimating the coupling of this environment to T D lines are discussed. Because of the quasi-static nature of MHD-EMP, the models are essentially simple DC circuit models. However, complications arise in attempting to treat realistic line configurations having a large number of support towers and an overhead shield or neutral wires. There models are discussed in detail. 3 refs., 5 figs., 1 tab.

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

1991-01-01

440

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

441

Parallel Power Flow AC\\/DC Converter with High Input Power Factor and Tight Output Voltage Regulation for Universal Voltage Application  

Microsoft Academic Search

In this paper, a new parallel-connected single phase power factor correction (PFC) topology using flyback converter in parallel with forward converter is proposed to improve the input power factor with simultaneously output voltage regulation taking consideration of current harmonic norms. Paralleling of converter modules is a well-known technique that is often used in medium-power applications to achieve the desired output

A. K. Jha; K. H. Babu; B. M. Karan

2006-01-01

442

Influence of the scatterer distribution on power delay profiles and azimuthal power spectra of mobile radio channels  

Microsoft Academic Search

We consider the distribution of scatterers that are responsible for the temporal and angular dispersion of mobile radio channel models. In a first step, we concentrate on the local scatterers around the mobile station. Various approximations for this distribution are analyzed, and their effect on the PDP (power delay profile) and APS (azimuthal power spectrum) are derived. We find that

Juha Laurila; Andreas F. Molisch; Ernst Bonek

1998-01-01

443

Preliminary analysis of Block Island Power Company's use of clean distributed resources to provide power to its customers  

SciTech Connect

This report is an analysis of the potential for Block Island Power Company (BIPCO) to use renewable energy and clean distributed resources to supply power to its customers. The preliminary conclusion of this work is that a system composed of clean distributed resources has the potential to be a technically and economically feasible alternative for BIPCO.

Hoff, T.E.

2000-01-25

444

Abnormal subcellular distribution of mature MUC2 and de novo MUC5AC mucins in adenomas of the rectum: Immunohistochemical detection using non-VNTR antibodies to MUC2 and MUC5AC peptide  

Microsoft Academic Search

Anti-mucin variable number tandem repeat (VNTR) antibodies have been used previously to demonstrate the de novo presence of MUC5AC and MUC6 mucin in colorectal adenomas and increased synthesis of MUC2, the major secreted mucin in normal colorectal mucosa. Here we examined secreted mucins in tubular, tubulovillous and villous adenomas of the rectum using non-VNTR antibodies designed to assess mature mucin.

Neil Myerscough; Paul A. Sylvester; Bryan F. Warren; Simon Biddolph; Paul Durdey; Michael G. Thomas; Ingemar Carlstedt; Anthony P. Corfield

2001-01-01

445

Two issues in the municipal ownership of electric power distribution systems. [Statistical\\/econometric scrutiny  

Microsoft Academic Search

Though municipal ownership of electric power distribution systems has been a growing public issue since the late 1960s, serious empirical econometric investigation of distribution has barely begun. The author opens with a critique of two recent works on distribution costs: one on distribution return to scale and one on comparative public\\/private efficiency. A new conceptualization of the factors influencing distribution

Neuberg

2009-01-01

446

Validating MCNP for LEU Fuel Design via Power Distribution Comparisons  

SciTech Connect

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

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

2008-11-01

447

A Integrated Power Flow Algorithm for Radial Distribution System with DGs Based on Voltage Regulating  

Microsoft Academic Search

It proposes a promising power flow analysis method for radial distribution system with distributed generations (DGs), combined with reactive power compensation facilities. In the power flow analysis, suitable models are determined for different DG units, Q-sources including Static Var Compensator, Switched Capacitor or Shunt Capacitor and Step Voltage Regulator. A helpful method is presented to deal with the PV node,

Liu Qingzhen; Cai Jinding

2010-01-01

448

Buckling Correction for Experimental Power Distribution within Fuel Assemblies in a Finite System  

Microsoft Academic Search

For design calculations to determine the local power distribution in a fuel assembly of a power reactor, the neutron flux is usually assumed to be symmetrical at the outer boundary of the assembly. In actuality, experimental data on power distributions are obtained in a finite system where this symmetry does not apply, so that the calculated values cannot be directly

Iwao KOBAYASHI; Shojiro MATSUURA

1970-01-01

449

Modeling and simulation of a distribution STATCOM using Simulink's Power System Blockset  

Microsoft Academic Search

This paper presents a study on the modeling of a STATCOM (Static Synchronous Compensator) used for reactive power compensation on a distribution network. The power circuits of the D-STATCOM and the distribution network are modeled by specific blocks from the Power System Blockset while the control system is modeled by Simulink blocks. Static and dynamic performance of a ±3 MVar

Pierre Giroux; Gilbert Sybille; Hoang Le-Huy

2001-01-01

450

Time-varying failure rate extraction in electric power distribution equipment  

Microsoft Academic Search

Reliability evaluation of power distribution system is very important to both power utilities and customers. It presents the probabilistic number and duration of interruption such as failure rate, SAIDI, SAIFI, and CAIDI. However, it has a fatal weakness at reliability index because of accuracy of failure rate. In this paper, the time-varying failure rate (TFR) of power distribution system equipment

Jong-Fil Moon; Jea-Chul Kim; Hee-Tae Lee; Sang-Seung Lee; Yong Tae Yoon; Kyung-Bin Song

2006-01-01

451

Computer analysis of harmonic distortion in electrical-power-distribution systems. Master's thesis  

Microsoft Academic Search

The number of nonlinear loads connected to power distribution systems is rapidly increasing. These loads disturb the sinusoidal nature of the power distribution systems to which they are connected. Consequently, all connected loads may be affected by even a single nonlinear load. This makes power quality an increasingly important issue, particularly in shipboard applications because equipment malfunction can cause the

Gedo

1991-01-01

452

The benefits of looping a radial distribution system with a power flow controller  

Microsoft Academic Search

In this paper the benefits of looping the conventional radial distribution system by a series power electronic system to control power flow has been investigated. The conventional radial electrical distribution system will change to loop or even meshed system due to the deregulation of electrical system and connection of Distributed Generation to Medium and Low voltage in future. However looping

M. Saradarzadeh; S. Farhangi; J. L. Schanen; P.-O. Jeannin; D. Frey

2010-01-01

453

Power distribution system switching operation scheduling for load balancing by using colored Petri nets  

Microsoft Academic Search

This study attempts to determine the daily load patterns of service zones, line switches, distribution feeders, and main transformers by using customer information in a customer information system (CIS) and information about distribution transformers in the outage management information system (OMIS) in Taiwan Power Company (Taipower). When a power distribution system is operating under normal conditions, the reconfiguration of feeders

Yu-Lung Ke; Chao-Shun Chen; Meei-Song Kang; Jaw-Shyang Wu; Tsung-En Lee

2004-01-01

454

Exploring the origin of power law distribution in single-molecule conformation dynamics: Energy landscape perspectives  

Microsoft Academic Search

We explored the origin of power law distribution observed in single-molecule conformational dynamics experiments. By establishing a kinetic master equation approach to study statistically the microscopic state dynamics, we show that the underlying landscape with exponentially distributed density of states leads to power law distribution of kinetics. The exponential density of states emerges when the system becomes glassy and landscape

Jin Wang; Li Xu; Kang Xue; Erkang Wang

2008-01-01

455

Simulating a Multi-Agent based Self-Reconfigurable Electric Power Distribution System  

Microsoft Academic Search

Electric power distribution systems can be found almost everywhere, from ship power systems to data centers. In many critical applications, there is need to maintain minimal operating capability under fault conditions. To carry out this goal it is necessary to develop energy distribution control techniques, which let implement a self-reconfigurable energy distribution system. This research project is looking at the

Janeth G. Gómez-Gualdrón; Miguel Vélez-Reyes

2006-01-01

456

Modelling of electrical power distribution systems by application of experimental design  

Microsoft Academic Search

The purpose of this paper is to demonstrate the application of the method of experimental design to the analysis of electrical power distribution systems. The theory of experimental design allows us to construct and experimentally verify the qualitative model of a power distribution system in order to analyse a significance of each component in distribution system modelling. The paper presents

Josnicjusz Nazarko

2000-01-01

457

A multi-agent approach for a self-reconfigurable electric power distribution system  

Microsoft Academic Search

Electric power distribution systems can be found almost everywhere, from ship power systems to data centers. In many critical applications, there is needed to maintain minimal operating capability under fault conditions. To carry out this goal it is necessary to develop energy distribution control techniques, which let implement a self-reconfigurable energy distribution system. This research project is looking at the

Janeth G. Gómez--Gualdrón; Miguel Vélez-Reyes

2006-01-01

458

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

459

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

NASA Astrophysics Data System (ADS)

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

Hung, Chih-Ju.

460

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

461

Modelling interference properties of SMPS dc power distribution busses  

NASA Astrophysics Data System (ADS)

The potential for a switched-mode power supply (SMPS) dc distribution bus to create electromagnetic interference (EMI) is examined using the SPICE circuit analysis program. Attaching a SMPS to a long length of transmission line essentially places a time changing load across that line. This generates reflections on the line that result in short periods over which the line voltage can change by a significant percentage of the nominal voltage (as much as 100 percent of the nominal dc bus voltage). Although these spikes do not substantially change the dc voltage of the bus, their rapid rise/fall times can generate high-frequency signals on the bus (as on long antenna) that can radiate and cause interference with other electronic subsystems. The frequency content of these voltage spikes can extend to frequencies well above the basic switch rate of the individual SMPS units that are connected to the bus. The potential EMI of these spikes is strongly related to the nominal dc operating voltage of the dc bus. The higher the bus voltage, the larger the amplitudes of these spikes.

Bowles, Betty A.; Paul, Clayton R.

462

Applying model-based diagnostics to space power distribution  

NASA Astrophysics Data System (ADS)

When engineers diagnose system failures, they often use models to confirm system operation. This concept has produced a class of advanced expert systems which perform model-based diagnosis. A model-based diagnostic expert system for a Space Station Freedom electrical power distribution testbed is currently being developed at the NASA Lewis Research Center. The objective of this expert system is to autonomously detect and isolate electrical fault conditions. Marple, a software package developed at TRW, provides a model-based environment utilizing constraint suspension. Originally, constraint suspension techniques were developed for digital systems. However, Marple provides the mechanisms for applying this approach to analog systems, such as the testbed, as well. The expert system was developed using Marple and Lucid Common Lisp running on Sun Sparc-2 workstation. The Marple modeling environment has proved to be a useful tool for investigating the various aspects of model-based diagnostics. This paper describes work completed to date and lessons learned while employing model-based diagnostics using constraint suspension within an analog system.

Quinn, Todd M.; Schlegelmilch, Richard F.

1994-03-01

463

Direct AC-AC converter and its applications to induction motor drives  

SciTech Connect

Several modulation schemes are used to reduce the harmonic content in a direct ac-ac converter. A new modulation scheme using a clipped sine reference is proposed and the harmonic content with this scheme is found to be lower. The performance of a three-phase induction motor fed by a direct ac-ac converter is analyzed using the equivalent-circuit model as well as the dynamic equations referred to a frame fixed to the stator. Operation of a bipolar direct ac-ac converter with high input utilization is studied. The performance of a single-phase induction motor fed by such a converter is analyzed using an equivalent-circuit model. The direct ac-ac converter makes us of several bilateral switches which enable both motoring and regeneration. A practical realization using power MOSFETs is given.

Khoei, A.

1989-01-01

464

Distribution of Resident Dolly Varden in Power Creek, Cordova, 2005-2007.  

National Technical Information Service (NTIS)

We sampled Dolly Varden in Power Creek above the Power Creek Hydroelectric Facility to document the distribution of Dolly Varden and investigate the possible effects of the design and operation of the water intake on resident Dolly Varden. Seven sampling ...

M. J. Daigneault S. H. Maclean

2012-01-01

465

7 CFR 1717.857 - Refinancing of existing secured debt-distribution and power supply borrowers.  

Code of Federal Regulations, 2013 CFR

...of existing secured debt-distribution and power supply borrowers...existing secured debtâdistribution and power supply borrowers...will be reviewed by RUS under normal review procedures for these...either advance approval or normal review, a lien...

2013-01-01

466

An EMTP study of flicker generation and transmission in power systems due to the operation of an AC electric arc furnace  

Microsoft Academic Search

Many contributions have been presented to the international technical community dealing with flicker generation due to AC electric arc furnaces (EAF). This paper presents the results of measurements carried out in the AC arc furnace feeding system, inside and outside the factory. Because the steel making factory under consideration is fed with two different lines from the same electrical grid,

B. Novo Ramos; J. L. de C. Parga

2000-01-01

467

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

Microsoft Academic Search

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

Sachin Jain; Vivek Agarwal

2008-01-01

468

A novel distributed photovoltaic power architecture using advanced Li-ion batteries  

Microsoft Academic Search

In this paper a novel distributed photovoltaic power architecture using advanced lithium-ion batteries is proposed, which is mainly composed of a switched mode power converter and a power management system. This system exhibits the advantages of better protection and more efficient control on charge\\/discharge of the battery than the traditional photovoltaic power system. Furthermore, better use of solar energy and

J. F. Reynaud; O. Gantet; P. Aloisi; B. Estibals; C. Alonso

2010-01-01

469

Power Management Strategies for a Microgrid With Multiple Distributed Generation Units  

Microsoft Academic Search

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

F. Katiraei; M. R. Iravani

2006-01-01

470

A methodology for the assessment of short duration voltage variations in electric power distribution systems  

Microsoft Academic Search

This paper deals with a new methodology for the assessment of power quality indices in electric power distribution systems. Power quality indices concerning short duration voltage variations, i.e. voltage sags and swells, are particularly introduced taking into account the needs for establishing power quality standards. The paper also presents a new proposal for a measurement protocol, a testing procedure to

N. Kagan; E. L. Ferrari; N. M. Matsuo; S. X. Duarte; J. L. Cavaretti; A. Tenorio; L. R. Souza

2002-01-01

471

Constructal Distribution of Solar Chimney Power Plants: Few Large and Many Small  

Microsoft Academic Search

In this paper, we show how to use constructal design to distribute solar chimney power production on available land area most efficiently. The solar chimney design is used as an example of solar-driven power plant. We found that the power generated per unit of land area is proportional to the length scale of the power plant, as well as to

S. Lorente; A. Koonsrisuk; A. Bejan

2010-01-01

472

Distributed Nonlinear Power Control in Cellular Mobile Networks With Each User Communicating With Several Base Stations  

Microsoft Academic Search

A simple distributed power control algorithm for communication networks with each user communicating with several base stations is proposed. We prove that the proposed algorithm is globally converging

Andrey V. Savkin

2007-01-01

473

Sequential Three-Phase Power Flow Calculation for Radial Distribution Systems via Three-Phase Z-Bus Distribution Factor  

Microsoft Academic Search

This paper aims to develop a sequential three-phase power flow program with three-phase ZBus distribution factor(TZBD) for power flow calculation. First, using monthly energy consumption of customers in a customer information system (CIS) and typical daily load pattern of customer classes, the quarter hourly loading profiles of distribution transformers were derived. The derived daily load curves are the loading database

Wei-Tzer Huang; Shiuan-Tai Chen

2009-01-01

474

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

SciTech Connect

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

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

2006-10-01

475

Over GHz low-power RF clock distribution for a multiprocessor digital system  

Microsoft Academic Search

Conventional digital clock distribution interconnection causes a severe power consumption problem for GHz clock distribution because of transmission line losses, and it exhibits difficult signal integrity problems due to clock skew, clock jitter and signal reflection. To overcome these conventional digital clock distribution limitations, optical clock distribution techniques, based on guided-wave optics and free-space optics, have been proposed. However, the

Woonghwan Ryu; Albert Lu Chee Wai; Fan Wei; Wai Lai Lai; Joungho Kim

2001-01-01

476

Impact of green power generation on distribution systems in a smart grid  

Microsoft Academic Search

This paper discusses green power distributed generation (DG) sources (of 10 MW or less), which are connected to the utility system at the distribution level, and their impact on distribution system reliability. Distribution circuits are designed to supply radial loads. Therefore, the introduction of green generation can result in: redistribution of fault and load currents on the feeder circuit, overvoltage

Charles J. Mozina

2011-01-01

477

Wind energy converters with FACTS Capabilities for optimized integration of wind power into transmission and distribution systems  

Microsoft Academic Search

In a lot of power systems renewable energies and especially wind power are main drivers for the actual restructuring of transmission and distribution systems. Enhanced power exchange capabilities over long distances will be one of the necessary transmission system characteristics in order to achieve a higher penetration level of wind power. Distribution systems change from pure load distribution to distributed

A. Beekmann; J. Marques; E. Quitmann; S. Wachtel

2009-01-01

478

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

479

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

480

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

Microsoft Academic Search

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

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

2008-01-01

481

A new generic family of saturable reactor-assisted soft-switching PWM DC-DC converters for high-power density distributed power systems  

Microsoft Academic Search

A generic family of high power density DC-DC power converter topologies with high-frequency AC link and without transformer isolation link is described. A saturable reactor assisted (SRA) soft switching mode constant frequency pulse width modulation (PWM) technique efficiently operates at a zero voltage switching transition scheme. This kind of quasi-trapezoidal wave mode PWM DC-DC power converter incorporates a small saturable

M. Nakaoka; M. Michihira; S. Hamada; Y. Murakami

1992-01-01

482

Power electronic converters distribution in HOST hybrid propulsion system  

Microsoft Academic Search

This paper deals with the design of power electronic converters to be used in the hybrid propulsion system of a multi-functions vehicle. A modern hybrid vehicle arrangement consists of one internal combustion engine, one or more electrical machines, storage systems based either on batteries or ultracapacitors; a number of power electronic converters are then required to control the power flows

A. Lidozzi; V. Serrao; L. Solero; F. Crescimbini

2007-01-01

483

Self-Similar Criticality: A link between cumulative power law distributions and fractal geometry  

NASA Astrophysics Data System (ADS)

Cumulative number-size distributions associated with many natural phenomena follow a power law. A data set that follows a power law may be considered fractal since both power laws and fractals are scale invariant. To understand the relationship between power law cumulative distributions and fractal geometry, we propose a model called Self-Similar Criticality (SSC). The model is based on a grid containing a self-similar distribution of critical cells. During each step of the model, a unit of material is supplied to the grid at a location selected at random. An event occurs when material is added to a critical cell, causing all material in occupied non-diagonal adjacent cells to leave the grid. The resulting cumulative distribution of event sizes follows an upper-truncated power law with a scaling exponent that depends on the fractal dimension of the critical cells. Unlike self-organized criticality (SOC) systems, which generate non-cumulative distributions with scaling exponents near unity, the SSC model generates power law distributions with a range of scaling exponents depending on the fractal dimension of the critical cells. The SSC model reproduces the observed power law distribution of seamount volumes in the Easter Island/Salas y Gomez Chain by initiating eruptions on a self-similar distribution of critical cells. For many natural systems, the SSC model may provide a link between observed power law distributions and fractal geometry.

Tebbens, S. F.; Burroughs, S. M.

2001-12-01

484

Collecting and categorizing information related to electric power distribution interruption events: customer interruption data collection within the electric power distribution industry  

Microsoft Academic Search

Reliability of electric power systems remains a top societal issue. While transmission disturbances draw national attention and scrutiny, service interruptions at the distribution level are the primary concern of end-use customers and their regulatory and governmental representatives. Much effort has been expended in developing methods to uniformly and consistently quantify reliability of distribution service based on electric system performance. However,

Rodney L. Robinson; Donald F. Hall; Cheryl A. Warren; Val G. Werner

2006-01-01

485

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

SciTech Connect

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

None

2012-01-09

486

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

Microsoft Academic Search

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

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

2007-01-01

487

Assessment of distributed solar-power systems: issues and impacts. Final report  

Microsoft Academic Search

The installation of distributed solar-power systems presents electric utilities with a host of questions. This study discusses some of the technical and economic impacts of these systems. Among the technical interconnect issues are isolated operation, power quality, line safety, and metering options. Economic issues include user purchase criteria, structures and installation costs, marketing and product distribution costs, and interconnect costs.

R. A. Moyle; H. Chernoff; T. C. Schweizer; J. B. Patton

1982-01-01

488

Multi-agent system based intelligent distributed control system for power plants  

Microsoft Academic Search

This paper presents an approach for intelligent distributed control of power plants using the concept of multi- agent systems (MAS). Solving the problem of optimally controlling a power plant based on multiple objectives, such as minimizing pollution, maximizing equipment life, etc., and coordinating each of the involved tasks that must be performed in distributed environments is a challenge, which involves

Kwang Y. Lee; Jason D. Head; Jason R. Gomes; Craig S. Williams

2011-01-01

489

Effect of radial power distribution on MITR-II fuel element and control blade worth  

SciTech Connect

This summary has been prepared to document and discuss several effects on fuel element and control blade reactivity worths that occur due to changes in the radial power distribution of the 5-MW(t) Massachusetts Institute of Technology Research Reactor (MITR-II). These results were obtained from reactor physics measurements and core power distribution calculations made during the past decade.

Bernard, J.A.; Kwok, K.S.; Lanning, D.D.; Clark, L.L. Jr.

1985-01-01

490

Mechanism of Unlimited WAN Expansion for Networks in Power Distribution Systems  

Microsoft Academic Search

There has been increasing use of intelligent electronic devices (IEDs) with communication capability for modern power distribution system protection, control and monitoring. This increases the need of LANs for IEDs to exchange data for improved and coordinated operations through peer-to-peer networking. Distributed Network Protocol (DNP3), commonly used for power system communications, is lack of effective internetworking LANs and individual IEDs.

T. Mander; F. Chen; R. Cheung; F. Nabhani

2006-01-01

491

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

Microsoft Academic Search

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

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

2010-01-01

492

Battery Energy Storage for Enabling Integration of Distributed Solar Power Generation  

Microsoft Academic Search

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

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

2012-01-01

493

Capacitor Placement and Replacement for Reactive Power Control in Radial Distribution System  

Microsoft Academic Search

The elegant approach to the reactive power control problem in a radial distribution system using fuzzy logic is presented. Voltage and power loss reduction of nodes are modeled by fuzzy membership functions. Fuzzy rules are used to determine the location for the capacitor placement in a radial distribution system. Shunt capacitor is placed on the node with the highest suitability.

M. S. Nagaraja; T. Ananthapadmanabha; B. Kantharaj; R. Prakash

2006-01-01

494

Study on power distribution strategy and optimization of fuel cell hybrid vehicles  

Microsoft Academic Search

In this study, comparative analysis of several types of power distribution and control strategies widely developed and used in the current fuel cell hybrid vehicles is presented, involving control theory, optimization methods and application. And a conclusion is drawn that fuzzy control strategies of power distribution is applicable for hybrid system characteristics of the existing fuel cell electric vehicles and

Li Yufang; Zhao Youqun; Yang Zhenglin

2008-01-01

495

Estimation of initiating event distribution at nuclear power plants by Bayesian procedure  

Microsoft Academic Search

Initiating events at nuclear power plants such as human errors or components failures may lead to a nuclear accident. The study of the frequency of these events or the distribution of the failure rate is necessary in probabilistic risk assessment for nuclear power plants. This paper presents Bayesian modelling methods for the analysis of the distribution of the failure rate.

Chen Guangming; T. L. Chu

1995-01-01

496

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

497

A method for minimal path determination in electric power distribution systems  

Microsoft Academic Search

Minimal path determination is one of the main steps in the reliability assessment of electric power transmission and distribution systems. This paper presents a new method for minimal path determination in electric power</