Showing papers on "Electric power published in 1998"

Universal power supply

Abstract: A power supply detects power requirements of an electrical device and configures itself to provide the correct power to the device. By using a connector that isolates the device from its battery, the power supply can provide power to the device, recharge the battery, recharge the battery while at the same time providing power to the device, or provide power to the device while preventing the battery from being recharged. A switch used with the connector creates various circuits and is controllable by the power supply, the electrical device, by signals from the electrical device, or by a third device. The power supply may provide power to a plurality of devices and may be used with other power supplies to form a power grid. A master control unit receives inputs from each of the power supplies and controls the delivery and supply of power being the power supplies.

Power systems restructuring : engineering and economics

Abstract: Preface. 1. Setting the Stage L. Hyman. Part I: Theoretical Challenges in Real-Time Operation. 2. Power Systems Operation: Old vs. New M. Ilic, F. Galiana. 3. Framework and Methods for the Analysis of Bilateral Transmissions F. Galiana, M. Ilic. Part II: Industry Experiences and Challenges. 4. The Political Economy of the Pool R. Green. 5. Practical Requirements for ISO Systems R. Masiello. Part III: Markets of the Future. 6. Agent Based Economics G. Sheble. 7. One-Part Markets for Electric Power: Ensuring the Benefits of Competition F.C. Graves, et al. Part IV: Planning in the New Industry. 8. System Planning under Competition R. Coxe, M. Ilic. 9. Transmission Networks and Market Power Z. Younes, M. Ilic. 10. Competitive Electric Services and Efficiency S.R. Connors. Part V: Power Systems Control in the New Industry. 11. New Control Paradigms for Deregulation L.H. Fink. 12. The Control and Operation of Distributed Generation in a Competitive Electric Market J. Cardell, M. Ilic. 13. Application of Dynamic Generation Control for Predatory Competitive Advantage in Electric Power Markets T. Gorski, C. DeMarco. Index.

Study of maximum power tracking techniques and control of DC/DC converters for photovoltaic power system

Abstract: As the electric power supplied by solar arrays depends on the insolation, temperature and array voltage, it is necessary to control the operating points to draw the maximum power of the solar array. The object of this paper is to investigate the maximum power tracking algorithms which were often used to compare the tracking efficiencies for the system operating under different controls. Besides, different type DC/DC converters were designed to evaluate the converter performance. A simple method which combines a discrete time control and a PI compensator is used to track the maximum power points (MPPs) of the solar array. The implementation of the proposed converter system was based on a digital signal processor (DSP) and the experimental results are presented.

Mineral insulating oil in transformers

Abstract: Nearly all load bearing transformers in electric power delivery systems around the world are filled with liquid. The liquid functions both as an electrical insulation and as a heat transfer fluid. The liquid in almost all of these units is transformer oil, petroleum-based insulating oil refined specifically to meet the requirements of this application. Transformers in electric power distribution and transmission systems are expected to function reliably and efficiently and to do this for many years. The quality of the oil in a transformer plays an important role in performing this function, and the characteristics of transformer oil have been examined and reported on for decades. This article discusses some of these characteristics and the relationships between these characteristics and the production and in-service performance of mineral transformer oil. Transformer oil is used around the world, but the emphasis here is on practices in the United States.

Method and apparatus for supplying contactless power

Abstract: A method and apparatus for supplying contactless power. Electrical power is transferred from a power source (100) to a load (500) through a primary energy converter that can be connected to the power source, through a primary inductive loop connected to the magnetically coupled to the primary (200) inductive loop, and then to a secondary energy converter. The power factor for the transfer of electrical energy is one. Multiple loads can receive power from the power source end, where the loads are located in zones, collisions between the loads can be prevented.

Operation of the unified power flow controller (UPFC) under practical constraints

Abstract: The UPFC is the most versatile and complex power electronic equipment that has emerged for the control and optimization of power flow in electrical power transmission systems. It offers major potential advantages for the static and dynamic operation of transmission lines, but it brings with it major design challenges, both in the power electronics and from the perspective of the power system. As the UPFC transitions from concept to full-scale power system implementation, the control and protection of this sophisticated equipment are of primary concern. This paper describes the basic control, sequencing and protection philosophies that govern the operation of the UPFC, subject to the practical constraints encountered in an actual high power installation. The operation of the UPFC is illustrated with representative results from a TNA study, undertaken jointly by the Electric Power Research Institute (EPRI), Western Area Power Administration (WAPA) and Westinghouse Science and Technology Center (STC).

Linear motion electric power generator

Abstract: A linear motion electric power generator for generating electric current from work done by an intermittent force. A moving magnet (2) is confined so that it can move with bi-directional linear, or approximately linear, motion through each of at least two coils (5 and 6). The coils are spaced apart from each other and connected electrically so that current produced in a first coil as a result of movement of the moving magnet is substantially in phase with current produced in said second coil. Embodiments of the invention provide pwoer from extremely low power mechanical forces and are useful for providing power for long life flashlights, for alarm systems and for communication devices located at places where conventional electric power sources are unavailable. Another preferred embodiment is a low profile unit which derives its mechanical power from repetitive forces such as the forces on the heel of a shoe during walking or running.

Lithium ion batteries : fundamentals and performance

Abstract: Rechargeable batteries with high energy density are in demand as energy sources for various purposes, such as handies, zero emission electric vehicles, or load levelling in electric power. Lithium batteries are the most promising to fulfill such needs because of their intrinsic discharge voltage with relatively light weight. This volume is an overview of the challenges facing the further development of lithium-ion batteries from the standpoint of both materials science and technology.

Paths of Innovation: Technological Change in 20th-Century America

Abstract: 1. Introduction 2. The organization and institutionalization of innovation, 1900-1940 3. The internal combustion engine 4. Chemicals 5. Electric power 6 The electronics revolution, 1947-1990 8. Concluding observations.

Electric Power Applications of Fuzzy Systems

Abstract: From the Publisher: This book offers an introduction to applications of fuzzy system theory to selected areas of electric power engineering. It presents theoretical background material from a practical point of view and then explores a number of applications of fuzzy systems. Most recently, there has been a tremendous surge in research and application articles on this subject. Until now though, there have been no books that put together a practical guide to the fundamentals and applications aspects. ELECTRIC POWER APPLICATIONS OF FUZZY SYSTEMS presents, under one cover, original contributions by authors who have pioneered in the application of fuzzy system theory to the electric power engineering field. Each chapter contains both an introduction to and a state-of-the-art review of each application area.Sponsored by:IEEE Power Engineering Society.

Surface replica fuel cell for micro fuel cell electrical power pack

Abstract: A miniature fuel cell system uses porous plastic membranes as substrates of fuel cells A cost effective pore-free electrode or inter electrolyte foil that is permeable only to hydrogen as an ion The new electrode makes direct alcohol fuel cells efficient It blocks the poisoning alcohol diffusion through the electrolyte Compound electrodes are formed by vacuum deposition methods and sluries That leads to printed circuit designs of small fuel cells systems integrated with rechargeable batteries and electrical power electronics to power applications that are currently powered by batteries By directly utilizing alcohol fuels the new fuel cells have higher energy per unit mass and higher energy per unit volume They are more convenient for the energy user, environmentally less harmful and less expensive than conventional batteries

A study on optimal sizing of stand-alone photovoltaic stations

Abstract: One major application of photovoltaic (PV) power has been in remote areas as isolated small power generation for essential electric power. This paper discusses issues in optimizing the use of such stations and presents a procedure to evaluate different PV schemes considering the stochastic natures of the insolation and the load. The reliability measures in terms of loss of load hours (LOLH), the energy loss and the total cost have been used as the indices for evaluation of different schemes. The insolation and the load demand are modeled as stochastic variables using historical data and experimentation respectively. The operation of various stand-alone schemes are simulated for a specific load. Actual commercially available panel and battery sizes with actual costs have been used in the various configurations studied. The long run expected values of the performance indices for various configurations of the solar station have been measured. Comparative analysis of the results show that higher cost not necessarily translates into better performance. The panel size and the battery size have different impacts on the indices of performance, and a proper balance between the two is necessary to optimize the operation of a stand-alone PV scheme.

Understanding Electric Utilities and De-Regulation

Abstract: THE ELECTRIC INDUSTRY AND ITS TRADITIONAL REGULATED STRUCTURE Introduction Electric Utility Functions and Systems Electric Utility Resources and Organization Vertical Integration and Monopoly Regulation Electric Utility Business Frameworks Government Regulatory Agencies and Commissions Electrical Equipment Suppliers and Developers A Complex Industry Undergoing Major Changes THE ELECTRIC INDUSTRY UNDER DE-REGULATION - AN OVERVIEW Introduction De-Regulation: Concepts and Evolution No Competition at the Retail Level Competition at the Wholesale Generation Level Independently Operated Regional Transmission Grids The Electricity Doesn't Care Although People and Money Do The Electric Utility Industry Under De-Regulation An Industry In Need of Fine Tuning A HISTORY OF THE ELECTRIC POWER INDUSTRY Three Intertwined Aspects Grew Simultaneously Growth of Electrical Usage The Growth of Electrical Systems Technology The Rise of the Electrical Utility Industry Looking to the Future For Further Reading ELECTRIC POWER Introduction Voltage, Current, and Power Characteristics of Electric Power and Systems Key Points For Further Reading USING ELECTRIC ENERGY Introduction A Flexible Form of Energy Four Basic Applications Electricity is Bought for End-Uses The Utility's Perspective on Customer Power Usage Conservation, Energy Efficiency, and Demand-Side Management Summary For Further Reading CREATING ELECTRICITY: POWER GENERATION Generating Electric Power Electric Generating Systems Types of Generating Plants Summary For Further Reading RENEWABLE POWER GENERATION Free Fuel and Low Environmental Impact Hydro Power Wind-Driven Power Generation Solar Power Other Renewable Generation Technologies Are Renewable Resources Practical? For Further Reading DISTRIBUTED GENERATION AND STORAGE Distributed Power Generation Types of Distributed Generators Distributed Power Storage Summary For Further Reading ELECTRIC UTILITY POWER SYSTEMS Introduction T&D System Equipment T&D System Layout Summary For Further Reading REGULATION AND DE-REGULATION Introduction Why Were Electric Utilities Regulated? Why De-Regulate? The Good and Bad of Utility Regulation Goals for and Effects of De-Regulation Comparing Four Approaches to Regulation and De-Regulation Increased Services From and Financial Pressures On LDCs For Further Reading DE-REGULATION AT THE WHOLESALE POWER LEVEL Introduction The Wholesale Power Marketplace Do Buyers Submit Bids? Buying Energy vs. Buying Capacity How is Wholesale Power Priced? Summary THE POWER GRID IN THE DE-REGULATED INDUSTRY Generation and Transmission in a De-Regulated Industry The Wholesale Transmission Level What is Being Sold at the Transmission Level? How Is Transmission Service Priced? The Eventual Winner: Locationally-Based Pricing? Summary of Key Points For Further Reading POWER DISTRIBUTION IN A DE-REGULATED INDUSTRY Introduction Open Access Distribution Changes in Distribution Operations Will Distribution Performance Improve Due to "Competition"? For Further Reading RETAIL SALES IN A FULLY DE-REGULATED INDUSTRY Introduction Load Aggregation and Services RESCO Identities and Industry Position How Does It All Work? For Further Reading SERVICE RELIABILITY AND AGING INFRASTRUCTURES Introduction Aging T&D Infrastructures Sustainable-Point Analysis of Aging Infrastructures Outages and Reliability For Further Reading SYSTEM BLACKOUTS AND OPERATIONAL COMPLEXITY Introduction Blackouts: An Overview Synchronized Operation of Power Systems Why Do Blackouts Occur? Summary and Concluding Comments For Further Reading GLOSSARY INDEX

Fuel consumption control for charge depletion hybrid electric vehicles

Abstract: A charge depletion method and apparatus for operating the electric motor and auxiliary power unit, such as an internal combustion engine, in a hybrid electric vehicle (HEV) separately or together depending upon the driving conditions. Operation of the electric motor and auxiliary power unit are coordinated as a function of a control policy for the auxiliary power unit based on desired least fuel consumption and/or vehicle emissions characteristics.

Are Municipal Electricity Distribution Utilities Natural Monopolies

Abstract: The purpose of this study is to analyse the cost structure of the Swiss electricity distribution utilities in order to assess economies of scale and density and the desirability of competition in the distribution of electric power. A translog cost function was estimated using panel data for a sample of 39 municipal utilities over the period 1988–1991. The results indicate the existence of economies of density for most output levels and the existence of economies of scale only for small and medium-sized electric utilities. The empirical evidence suggests that franchised monopolies, rather than side-by-side competition, is the most efficient form of production organization in the electric power distribution industry. Further, the majority of the utilities analysed do not operate at an optimal service territory size. Therefore, the consolidation of small utilities whose service territories are adjacent is likely to reduce costs.

Methods for utilizing the electrical and non electrical outputs of fuel cell powered vehicles

Abstract: The present invention provides a method and apparatus for generating electrical power from multiple vehicles powered by fuel cells while the vehicles are parked in a parking lot. A plurality of spaced-apart electrical receptacles are provided for receiving an electric cable for connection to a parked vehicle for electrically connecting the fuel cell in each of the parked vehicles to the plurality of electrical receptacles. An electric power grid is electrically connected to the plurality of electrical receptacles for transferring D.C. electrical power from the fuel cells in the parked vehicles to the electric power grid. At least one electric power collection station is electrically connected to the electric power grid for collecting at a common point the D.C. electric power in the electric power grid. In addition, at least one inverter is electrically connected to the electric power collection station for converting the D.C. electric power to A.C. electric power. Apparatus is provided for supplying the A.C. electric power to a load or a utility grid.

Hybrid electrical power system

Abstract: A hybrid electrical power system includes a solid oxide fuel cell (14) and a turbomachine (12). Fuel flow to the turbomachine is increased in response to demands for boost power, whereby the turbomachine's electrical generator provides the boost power. The turbomachine supplies heated, high pressure air to the solid oxide fuel cell, bringing the solid oxide fuel cell to its required operating temperature. Waste from the solid oxide fuel cell, including exhaust air and unreacted fuel, is utilized by the turbomachine.

Apparatus for metering electrical power and electronically communicating electrical power information

Abstract: An apparatus for electronically communicating metered electrical power is disclosed. A first processor receives voltage and current signals and determines electrical power. The first processor generates an power signal representative of the electrical power determination. A second processor, connected to said first processor, receives the power signal and generates an output signal representative of electrical power information. A output device is connected to receive the output signal to output the electrical power information. The first processor determines units of electrical power from the voltage and current signals and to generates an power signal representative of the determination of such units and the rate at which the units are determined. The output devices may be one of a display, optical port and an option connector. When the output device is a display, the second processor may generate a disk signal representative of a rate of disk rotation in relation to the rate at which the units are determined, wherein the output signal to the display is representative of the units, the rate at which said units are determined, and the rate of disk rotation. The first processor, while concurrently determining units of electrical power, further may determine watt units, apparent reactive power units and the rate at which such units are determined, wherein the watt units, the apparent reactive power units and the rate at which such units are determined are displayed. The first processor may also meter multiple types of electrical power and generates power signals. The second processor, when connected to the optical port, generates an output signal in response to the power signals, wherein the generation of the output signal includes the multiplexing of the power signals into the output signal.

Household power supply system using electric vehicle

Abstract: A household power supply system using an electric vehicle, comprises an external power system, a house with an indoor power line, an electric vehicle having a vehicle power system with vehicle batteries, a charger/discharger for connecting separably the indoor power line and the vehicle power system, and a controler for controlling power supply to the indoor power line. The power supply system is capable of supplying energy from the household power supply to the vehicle batteries at the normal state, and conversely supplying energy from the vehicle batteries to the indoor power line at the time of emergency, etc. to enable employment of indoor electric equipments.

Rate-based load shed module

Abstract: A load shed module for use in a power distribution system that includes facility for delivering both electrical power and electrical power rate information from a utility supplier. The load shed module includes an enclosure having a power plug for receipt in a standard utility power outlet such as a wall socket, and a power socket on the enclosure for connection to a power load. A relay switch is disposed within the enclosure for selectively electrically connecting the plug to the socket to deliver electrical power to the load coupled to the socket. A rotary switch is mounted on the enclosure, and rotary rate indicia is provided on the enclosure adjacent to the rotary switch and coordinated with position of the rotary switch for operator selection of a rate tier at which the socket is to be disconnected from the plug. Utility power rate information is received from the utility supplier and compared with the rate tier selected by the operator at the rotary switch. When the power rate information equals or exceeds the selected rate tier, the module socket is disconnected from the plug so that the associated load is effectively disconnected from the power distribution system.

Shipboard systems deploy automated protection

Abstract: The electric power systems in today's US Navy ships supply energy to sophisticated systems for weapons, communications, navigation and operation. To maintain the availability of energy to the connected loads that keep all systems and equipment operational, the electric systems utilize fuses, circuit breakers and protective relays to interrupt the smallest portion of the system under any abnormal condition. New techniques are being developed that make use of advanced monitoring and control, automated failure location and automated intelligent system reconfiguration and restoration. The goal is to increase survivability, eliminate human mistakes, make intelligent reconfiguration decisions more quickly, reduce the manpower required to perform the functions and provide optimal electric power service through the surviving system. With fewer personnel being available on ships in the future, the presence of such a system will become essential for maintaining optimal electric power service.

Status of the United States Air Force's More Electric Aircraft initiative

Abstract: Since the early 1990's, the USAF has been successfully pursuing advancement in aircraft electrical power system technologies as a means of collectively establishing the capability to reduce dramatically or eliminate centralized hydraulics aboard aircraft and replace them with electrical power as the motive force for all aircraft functions. This overall approach (called the More Electric Aircraft, MEA) has been analytically determined to provide dramatic improvements in reliability, maintainability, supportability and operations/support cost as well as enhancements in aircraft weight, volume, and battle-damage reconfigurability. A time- and technology availability-phased research and development program has been structured to demonstrate the required electrical component and subsystems performance to allow equivalent or improved aircraft performance over the use of hydraulic power. This paper provides: (1) a brief historical treatment of technology milestones achieved which enabled the MEA approach; (2) a status of USAF and DoD research and development programs in electrical power generation, distribution, energy storage, systems integration and flight testing; (3) a description of some of the USAF's planned demonstration activities in aircraft electrical power subsystems; and (4) the dual use nature of many of these technologies enabling a variety of electric and hybrid electrically-propelled military weapon systems and commercial vehicles.

The spherical tokamak path to fusion power

Abstract: The low-aspect-ratio tokamak or spherical torus (ST) approach offers the two key elements needed to enable magnetic confinement fusion to make the transition from a government-funded research program to the commercial marketplace: a low-cost, low-power, small-size market entry vehicle and a strong economy of scale in larger devices. Within the ST concept, a very small device (A = 1.4, major radius ~1 m, similar size to the DIII-D tokamak) could be built that would produce ~800 MW(thermal), 200 MW(net electric) and would have a gain, defined as QPLANT = (gross electric power/recirculating power), of ~2. Such a device would have all the operating systems and features of a power plant and would therefore be acceptable as a pilot plant, even though the cost of electricity would not be competitive. The ratio of fusion power to copper toroidal field (TF) coil dissipation rises quickly with device size (like R3 to R4, depending on what is held constant) and can lead to 4-GW(thermal) power plants with QPL...

Electric power quality: a tutorial introduction

Abstract: Electric power quality is an aspect of power engineering that has been with us since the inception of power systems; however, topics in power quality have risen to the forefront since the advent of high power semiconductor switches and networking of transmission and subtransmission systems. Also, the trends in modern power engineering have been to extract the most from the existing installed power system, and this too has placed stress on issues of sinusoidal waveform fidelity, absence of high and low voltage conditions and other AC waveform distortion. A tutorial introduction to the concepts of electric power quality is presented in this paper.

Power distribution to nodes in a distributed system

Abstract: A system in which remote nodes are supplied with electrical power using existing network communication links. A communication device in a system according to the present techniques routes electrical power to a remote node via a set of unused lines of a network communication link used for communication with the remote node. The electrical power distributed to the remote node may be AC or DC power.

Hybrid electric vehicle with battery management

Abstract: A hybrid electric vehicle comprises an electric motor, a battery pack for the electric motor, a generator driven by an engine to provide electric power used for charging the battery pack, and a battery management for the battery pack. The battery management determines a current value of battery temperature (BT) of the battery pack and a current value of state of charge (SOC) within the battery pack. What are stored are a first set of varying SOC values and a second set of varying SOC values against varying BT values. The first set of varying SOC values are minimum SOC values required for the battery pack to produce a constant electric power output at varying BT values. The second set of varying SOC values are each indicative of an allowable upper limit to the quantity of electric charge that will accumulate in the battery pack due to operation of charging the battery pack with a constant electric power input at a corresponding BT value. The battery management provide an actuator command for control of electric power input upon charging the battery pack in response to the current value of BT, the current value of SOC, the first set of varying SOC values and the second set of varying SOC values.