Showing papers on "Electric power published in 2003"

Distributed generation: Semantic hype or the dawn of a new era?

Abstract: As the electric utility industry continues to restructure, driven both by rapidly evolving regulatory environments and by market forces, the emergence of a number of new generation technologies also profoundly influences the industry's outlook. While it is certainly true that government public policies and regulations have played a major role in the rapidly growing rate at which distributed generation is penetrating the market, it is also the case that a number of technologies have reached a development stage allowing for large-scale implementation within existing electric utility systems. At the onset of any discussion related to distributed generation, one question begs to be answered: is the fact that electric power producing facilities are distributed actually a new and revolutionary concept? Have power plants not always been located across broad expanses of land? The answer to these questions clearly is that electric power plants have always been sited all across the service territories of the utilities owning them. Hence, the opening question: as with many so-called innovations that have been put forward during the recent past, is the entire concept of distributed generation a simple semantic marketing hype or are we actually at the dawn of a new electric power generation era? We believe that a new electric power production industry is emerging, and that it will rely on a broad array of new technologies. This article sets the stage for distributed generation covering such topics as: the present power production situation; what distributed generation is; capability ratings and system interfaces; market penetration of internal combustion engine generators, fuel cells and microturbines; potential generation mix issues, network considerations including power quality, reactive power coordination, reliability and reserve margin, reliability, network redundancy, safety and accountability; public policy and regulatory impact; and standards.

Wind Turbine Operation in Electric Power Systems

Abstract: The first € price and the £ and $ price are net prices, subject to local VAT. Prices indicated with * include VAT for books; the €(D) includes 7% for Germany, the €(A) includes 10% for Austria. Prices indicated with ** include VAT for electronic products; 19% for Germany, 20% for Austria. All prices exclusive of carriage charges. Prices and other details are subject to change without notice. All errors and omissions excepted.

Risk assessment in energy trading

Abstract: This paper provides a state-of-the-art summary of risk assessment in energy trading. Techniques from financial engineering are needed by electric energy companies to manage price risk. These tools are needed by suppliers, distributors, and traders in a competitive electric power marketplace. Tools that have been adapted to the specific environment of the electric power system include portfolio analysis and hedging instruments. This paper provides a comprehensive critical literature survey of what has been applied to date in the power markets and which areas continue to need additional research. One example market scenario is used throughout the paper to demonstrate the usefulness of the risk assessment methods.

System for power delivery over data communication cabling infrastructure

Abstract: A system for generating, delivering and distributing electrical power to network elements over a data communication network infrastructure within a building, campus or enterprise. Consolidating power distribution and data communications over a single network simplifies and reduces the cost of network element installation and provides a means of supplying uninterrupted or backup power to critical network devices in the event of a power failure. The invention includes power/data combiners that combine a data communication signal with a low frequency power signal. The combined signal is transported over the LAN infrastructure where a power/data splitter extracts the data signal and the power signal and generates two separate outputs. The power over LAN system of the present invention operates with high bandwidth data communication networks, i.e., 10 Mbps, 100 Mbps, 1000 Mbps. The electrical power distributed over the LAN can be delivered as DC or low frequency AC voltages which in either case will not interfere with data communications signals. The electrical power delivered over data communications cable can be transmitted using one or more spare pairs in the cable or over the receive and transmit wires.

Method and apparatus for reading and controlling utility consumption

Abstract: A method and system for controlling electric power consumption using a computer to create a forecast and then controlling devices that use power based on the forecast. An automatic reader device is used to gather power consumption data from a point of utility service. The power consumption data is then provided to a computer. The computer is used to create a forecast of energy use for instantaneous demand and time-based usage. The computer then provides alerts based on the forecast for the manual or automatic control of devices that consume electricity. The system may be managed locally or remotely by a computer, PDA, cell phone or other network enabled device.

Offshore wind turbine

Abstract: A wind energy conversion system optimized for offshore application. Each wind turbine includes a semi-submersible hull with ballast weight that is moveable to increase the system's stability. Each wind turbine has an array of rotors distributed on a tower to distribute weight and loads and to improve power production performance where windshear is high. As much of the equipment associated with each rotor as possible is located at the base of the tower to lower the metacentric height. The equipment that may be emplaced at the bottom of the tower could include a power electronic converter, a DC to AC converter, or the entire generator with a mechanical linkage transmitting power from each rotor to the base of the tower. Rather than transmitting electrical power back to shore, it is contemplated to create energy intensive hydrogen-based products at the base of the wind turbine. Alternatively, there could be a central factory ship that utilizes the power produced by a plurality of wind turbines to create a hydrogen-based fuel. The hydrogen-based fuel is transported to land and sold into existing markets as a value-added 'green' product.

Design, fabrication and testing of the P3 micro heat engine

Abstract: The development and testing of a micro heat engine is presented. For the first time the production of electrical power by a dynamic micro heat engine is demonstrated. The prototype micro heat engine is an external combustion engine that converts thermal power to mechanical power through the use of a novel thermodynamic cycle. Mechanical power is converted into electrical power through the use of a thin-film piezoelectric membrane generator. This design is well suited to photolithography-based batch fabrication methods, and is unlike any conventionally manufactured macro-scale engine.

Hybrid energy off highway vehicle electric power management system and method

Abstract: An energy management system for use with a hybrid energy off highway vehicle. The off highway vehicle includes a primary energy source and a power converter driven by the primary energy source for providing primary electric power. A traction bus is coupled to the power converter and carries the primary electric power. A traction drive is connected to the traction bus. The traction drive has a motoring mode in which the traction drive is responsive to the primary electric power for propelling the off highway vehicle. The traction drive has a dynamic braking mode of operation wherein said traction drive generates dynamic braking electrical energy. The energy management system includes an energy management processor for determining a power storage parameter and a power transfer parameter. An energy storage system is connected to the traction bus and is responsive to the energy management processor. The energy storage system selectively stores electrical energy as a function of the power storage parameter and selectively supplying secondary electric power from the stored electrical energy to the traction bus as a function of the power transfer parameter.

Vehicle driving force control apparatus

Abstract: A vehicle driving force control apparatus controls a control torque command of an electric motor based on a power supplying condition of an electric power source. The power source supplies electric power to the electric motor that drives at least one wheel of the vehicle. An electric power supplying status detecting section determines an electric power supplying capacity of the electric power source based on the power supplying condition of the power source, while an electric motor torque control section controls the control torque command of the electric motor based on the power supplying condition determined by the electric power supplying status detecting section. Preferably, an internal combustion engine that drives at least one other wheel also drives a generator that acts as the power source of the electric motor. The vehicle driving force control apparatus is especially useful in a four-wheel drive vehicle.

System and method for generating and sustaining a corona electric discharge for igniting a combustible gaseous mixture

Abstract: The invention relates to a system for igniting a fuel-air mixture in a combustion chamber with a corona discharge. The system comprises an electrode inside of the combustion chamber, an electric circuit which provides radio frequency electric power to the electrode, and a ground formed by the combustion chamber walls. A radio frequency voltage differential formed between the electrode and the ground produces a radio frequency electric field therebetween which causes a fuel-air mixture to ionize resulting in combustion of the fuel-air mixture. The system can be utilized in engines such as internal combustion engines or gas turbine engines, for example.

Analysis of biomass-residue-based cogeneration system in palm oil mills

Abstract: Palm oil mills in Malaysia operate on cogeneration system using biomass residue as fuel in the boiler. The boiler produces high pressure and temperature steam which expands in a backpressure steam turbine and produces enough electric power for the internal needs of the mill. The exhaust steam from the turbine goes to an accumulator which distributes the steam to various processes in the mill. The study were made on seven palm oil mills in the Perak state in Malaysia. The primary objectives of the study are to determine boiler and turbine efficiencies, energy utilization factor, oil extraction rate and heat/power ratio for various palm oil mills working under similar conditions and adopting same processes. The palm oil industry is one of those rare industries where very little attempt is made to save energy. The energy balance in a typical palm oil mill is far from optimum and there is considerable scope for improvement. Bench-marking is necessary for the components in the mill. Energy-use bench-marking can give an overview of energy performance of the mills. The calculations were done to get net gain in power when back pressure turbine is replaced by a condensing turbine. It was found that the boiler and turbine have low thermal efficiencies compared to conventional ones used in power plants due to non-homogeneity and non-uniform quality of the fuel. The extraction rate was around 0.188. The use of condensing turbine increase the power output by 60% and the utilization factor was found to be 65% for the cogeneration system.

System and method for implementing XML on an energy management device

Abstract: A power management architecture for an electrical power distribution system, or portion thereof, is disclosed. The architecture includes multiple intelligent electronic devices (“IED's”) distributed throughout the power distribution system to manage the flow and consumption of power from the system. The IED's are linked via a network to back-end servers. Power management application software and/or hardware components operate on the IED's and the back-end servers and inter-operate via the network to implement a power management application. The architecture provides a scalable and cost effective framework of hardware and software upon which such power management applications can operate to manage the distribution and consumption of electrical power by one or more utilities/suppliers and/or customers which provide and utilize the power distribution system. In particular, each IED is capable of incrementally generated or consuming communicated XML documents containing power management data without having to buffer the complete XML document is memory before, during or after processing.

Micromachined CMOS thermoelectric generators as on-chip power supply

Abstract: As the power consumption of a large number of microelectronic devices has been continuously reduced in recent years, power supply units of a few microwatts have become sufficient for their operation. Our improved micro-scale thermoelectric generator (/spl mu/-TEG) is based on polysilicon surface micromachining and is designed to convert waste heat into electrical power. Since this device is compatible with standard CMOS fabrication processes, it can be easily integrated on chip level and matches the needs for low-cost and small-size systems. As thermoelectric materials, both, pure poly-Si and poly-Si/sub 70%/Ge/sub 30%/ have been investigated. Emphasis was placed on a thermally optimized design and the reduction of the total electrical resistance of the generator. As a result of these improvements, a voltage of 5 V and an electrical power output of 1 /spl mu/W for a matched consumer is achieved with generators of 1 cm/sup 2/ in size at a temperature drop of about 5 K.

Use of piezoelectric energy harvesting devices for charging batteries

Abstract: Piezoelectric materials can be used as mechanisms to transfer ambient vibrations into electrical energy that can be stored and used to power other devices. With the recent surge of micro scale devices, Piezoelectric power generation can provide a conventional alternative to traditional power sources used to operate certain types of sensors/actuators, telemetry, and MEMS devices. In this paper, two types of piezoelectric materials were experimentally investigated for use as power harvesting devices. The two types being the commonly used monolithic piezoelectric (PZT) and Macro Fiber Composites (MFC), which were recently developed at the NASA Langley Center. Our experimental results estimate the efficiency of these devices and identify the feasibility of their use in real world applications. In general the power produced by the vibration of a piezoelectric device is on the order of a few milliwatts which is far too little to power for most applications. Therefore, each the transducer is used to charge nickel metal hydride batteries of varying sizes to compare their performance and ability of to store electrical power. The results presented in this paper show the potential of piezoelectric materials for use in power harvesting applications.

Design methodology of a combined battery-ultracapacitor energy storage unit for vehicle power management

Abstract: Hybrid and electric vehicles (HEV, EV) require some form of energy storage in order to achieve load leveling or efficiently manage power flows, mainly when accelerating or decelerating. Traditionally, batteries have been used but recently ultracapacitors have become potential candidates for energy storage in HEV/EV applications. To this end, this paper first presents a methodology for determining whether an energy storage unit (ESU) should consist of only batteries, only ultracapacitors or a combination of both. An example illustrates the feasibility of the proposed ideas. Finally, the paper concludes with a cost analysis of the different ESU alternatives.

Heat conversion system

Abstract: An energy conversion system is provided for converting heat energy from a variety of heat sources to electric power for operating electrical appliances. The system may be incorporated in a power on demand pilot system of a gas operated equipment to provide the sole electric power for operating the equipment. Thermoelectric modules provide the basic transducer for converting the heat energy to electric power and a heat pipe is employed for conducting the heat energy from a heat source to the conversion system.

Power cogeneration system and apparatus means for improved high thermal efficiencies and ultra-low emissions

Abstract: A power cogeneration system employing a partially-open gaseous fluid cycle method and apparatus devices for oxy-fuel combustion conversion of a given hydrocarbon composition fuel's heat-value energy into mechanical or electrical power energy, and transferred useful heat energy, with accompanying large reductions of consumed fuel and undesirable exhaust emissions.

Camera for monitoring utilizing power line communication

Abstract: The invention provides a camera for monitoring using power line communication, and transmitting the state of a monitoring area during power stoppage to a master set after the power stoppage is restored even when the supply of electric power is interrupted by the power stoppage. A power monitoring section detects the interruption of AC electric power from the power line, and switches operating power within the camera to power from a secondary battery. A control section sets the entire control of the camera to a mode at the power stopping time. The operation of a picture section is controlled so as to pick-up one static image every constant time, and the picture section sequentially stores the picked-up static image to a data storage section. A voice section stops an operation for collecting a sound. The control section stops communication with a master set. When the AC electric power is restored from the power line, the operating power is switched to the electric power from the power line. When a user utilizing the master set knows the restoration of the power, the user gives commands for reading image information stored during the power stoppage to the camera for monitoring, and monitors the state during the interruption of the AC electric power retroactively to the past.

All-electric aircraft

Abstract: While there are many technical challenges to overcome before a fully electric aircraft is operational, the benefits of such a system are significant. For the industry to move forward the More Electric Aircraft and its partner concept, the More Electric Engine (MEE) must become reality in the next 10 to 20 years. This paper discusses the development of such engines and aircraft.

Co-generated power supply system

Abstract: In a co-generated power supply system for performing dispersed power supply to a load, a wind turbine generator, a solar cell and a fuel cell whose rated voltages are made equal to a rated voltage of a storage battery are used as DC power sources. These DC power sources, a commercial AC power source and the load are connected to each other via a bi-directional electronic transformer. Thus, the co-generated power supply system, in which the electric power of a natural energy system having many fluctuation factors is combined with stable electric power such as a load leveling battery or a fuel cell, allows the stable electric power to be supplied to the load via the electronic transformer commonly, thereby reducing the cost and enhancing the performance of the entire system.

System for generating electric power from a rotating tire's mechanical energy using reinforced piezoelectric materials

Abstract: A system for generating electric power from a rotating tire's mechanical energy concerns a power generation device with a piezoelectric structure and an energy storage device. The piezoelectric structure preferably comprises a plurality of piezoelectric fibers embedded in a generally unidirectional fashion within an epoxy matrix. The piezoelectric structure may be mounted on a support substrate that helps distribute mechanical strain to which the piezoelectric fibers are subjected in a substantially uniform fashion. The piezoelectric structure is preferably mounted within a tire structure such that electric charge is generated therein as the wheel assembly moves along a ground surface. Electrode layers within the piezoelectric structure are coupled to a power conditioning module that rectifies the resultant electric current from the piezoelectric structure and stores it in an energy storage device, preferably an electrolytic capacitor. A rechargeable battery may also be provided for storing additional charge generated within the piezoelectric structure. A regulated voltage source is provided from the energy stored in the power generation device and can be used to power various electronics systems integrated within a tire or wheel assembly. An example of an integrated tire electronics system for use with the disclosed power generation device corresponds to a tire monitoring system that wirelessly transmits such information as tire pressure, temperature and identification variables to a remote receiver location.

Electric Power Distribution System Performance in Carolina Hurricanes

Abstract: This paper describes a quantitative investigation of the performance of electric power distribution systems in North and South Carolina in recent hurricanes. The study is based on large databases of outages in five recent hurricanes. The databases were compiled from Carolina Power and Light and Duke Power, two major electric power companies that together serve most of the Carolinas. The study specifically explores hurricane disruption in terms of number of outages and customers affected; geographic distribution, duration, and causes of outages; and types of equipment affected (for example, transformers, reclosers, fuses). It also examines the relationships between disruption and maximum gust wind speed, rainfall, and land cover type.

Autonomous solid state lighting system

Abstract: The autonomous solid state lighting system (100) of the present invention has a charge mode which collects energy and produces electric power with a solid state energy source (110), converts the voltage of the electric power using a bi-directional power converter (130), and stores the power in an energy storage device (140), and has a discharge mode which draws electric power from the energy storage device (140), converts the voltage of the electric power using the bi-directional power converter (130), and produces light from a solid state light source (120). A controller (150) controls the charge and discharge modes. In one embodiment, the solid state energy source (110) can be a solar cell panel, the solid state light source (120) can be an LED module, and the energy storage device (140) can be a battery pack.

Power Electronics as an Enabling Technology for Renewable Energy Integration

Abstract: The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity, to produce, distribute and use the energy as0 efficient as possible and furthermore to set up incentives to save energy at the end-user. Two major technologies will play important roles to fulfill those targets. One is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficiency power electronics in power systems for high efficiency and high performance applications. This paper discusses both areas, in particular the power electronic application m wind power integration