Showing papers on "Electric power published in 1996"

A market mechanism for electric power transmission

Abstract: As competition is introduced into the electric power industry, access and pricing policy for transmission will play a pivotal role in shaping future market structure and performance. The externalities associated with the loop flow phenomenon in an electric power network constitute a significant barrier to the formation of efficient markets for electricity and transmission services. In this paper, we present a new approach to the design of an efficient market mechanism for transmission access that resolves these externalities. Under a trading rule that combines the Coasian and the Pigouvian principles to resolution of externalities, property rights are defined so that a competitive market could be established for transmission services and electricity to achieve a social optimum within a power pool. We characterize a dynamic trading process which is Lyapunov stable and always converges to a competitive equilibrium. Finally, we discuss some practical applicability and long-term investment issues.

System for monitoring and controlling electrical consumption, including transceiver communicator control apparatus and alternating current control apparatus

Abstract: A system that monitors and controls electrical power consumption that will be retrofitted to a typical consumer electrical power arrangement (typical arrangement-electrical feed line from a provider, a meter, a circuit breaker and individual input wiring to a plurality of electrical devices, appliances and outlets). The system includes a control unit which receives information from an electromagnetic pickup device from which real time electrical consumption is determined over very short periods of time. The control unit has a main data processing and storage processor for retaining information and it may include a communication microprocessor for sending signals to corresponding modules. The electromagnetic pickup device uniquely measures the electromagnetic flux emanating at each output wire from each of the individual circuit breakers in a breaker box. The modules have filters which release electrical power to the individual electrical devices, appliances and outlets at a controlled, economic rate.

Electrical power distribution and communication system for an underwater cable

Abstract: An underwater cable arrangement includes systems and method for distributing and/or transferring power and/or data to internal devices and external devices disposed along an underwater cable Under water coupling systems and underwater electrical devices may be used in the distribution and/or transfer of the power and/or data

Power electronic interface circuits for batteries and ultracapacitors in electric vehicles and battery storage systems

Abstract: A method and apparatus for load leveling of a battery in an electrical power system includes a power regulator coupled to transfer power between a load and a DC link, a battery coupled to the DC link through a first DC-to-DC converter and an auxiliary passive energy storage device coupled to the DC link through a second DC-to-DC converter. The battery is coupled to the passive energy storage device through a unidirectional conducting device whereby the battery can supply power to the DC link through each of the first and second converters when battery voltage exceeds voltage on the passive storage device. When the load comprises a motor capable of operating in a regenerative mode, the converters are adapted for transferring power to the battery and passive storage device. In this form, resistance can be coupled in circuit with the second DC-to-DC converter to dissipate excess regenerative power.

Exhaust gas purification device of an engine

Abstract: An exhaust gas purification device of an engine comprising a particulate filter arranged in an exhaust passage. An electric motor able to impart a vehicle drive power separate from the engine and able to generate electric power from the engine is provided. After the particulate filter finishes being warmed up, when the temperature of the particulate filter is low, the output torque of the engine is increased and the amount of increase of the output torque is consumed by the power generating action of the electric motor.

Design and dynamic response characteristics of 400 MW adjustable speed pumped storage unit for Ohkawachi Power Station

Abstract: At 400 MW, the world's largest adjustable speed pumped storage unit for Ohkawachi Power Station, the Kansai Electric Power Co., Inc., Japan, was commissioned on Dec. 3, 1993. It can change power in steps of at least 32 MW in the generate mode and at least 80 MW in the pump mode, within 0.2 s. This paper describes principal design considerations for the control systems of the machine and presents actual performance of the machine with reference to some typical oscillograph charts.

Real-time monitoring and dynamic thermal rating of power transmission circuits

Abstract: ANSI standards for power equipment, and a vast store of technical literature, describe various methods by which thermal ratings may be adjusted if actual weather conditions are known or if the "overload" is to be applied for a limited period of time. These methods have been given various names including dynamic thermal rating, on-line rating, and dynamic ratings to describe the process of adjusting thermal ratings of power equipment for actual weather conditions and actual electrical load patterns. This paper discusses in detail a project undertaken by the Electric Power Research Institute (RP 3022-7) as part of its research on Flexible AC Transmission. This project avoids dependence on temperature measurement, instead, calculating critical equipment component temperatures based solely on real-time weather and electrical current. Inexpensive, commercially available weather stations, digital data loggers, and IBM-compatible PC computers are combined with sophisticated thermal algorithms to yield a portable, flexible, instrumentation method which can rate several transmission circuits simultaneously, including underground cable, overhead lines, power transformers, current transformers, switches, bus, line traps, and circuit breakers. Useable increases of 5% to 15% in the thermal capacity of transmission equipment circuits result.

Plasma-CVD method and apparatus

Abstract: The present invention provides a plasma CVD method for forming a plasma from a deposition material gas by application of an electric power, and thereby forming a film on a deposition target object in the plasma, wherein the formation of the plasma from the material gas is performed by applying an RF power and a DC power, and the DC power is applied to an electrode carrying the deposition target object. The present invention also provides a plasma CVD apparatus for forming a plasma from a deposition material gas by applying an electric power from the power applying means, and thereby forming a film on a deposition target object by exposing the deposition target object to the plasma, wherein the power applying means includes RF power applying means and DC power applying means, and the DC power applying means applies an electric power to the electrode carrying the deposition target object.

Apparatus and method for maximizing power delivered by a photovoltaic array

Abstract: A method and apparatus for maximizing the electric power output of a photovoltaic array connected to a battery where the voltage across the photovoltaic array is adjusted through a range of voltages to find the voltage across the photovoltaic array that maximizes the electric power generated by the photovoltaic array and then is held constant for a period of time. After the period of time has elapsed, the electric voltage across the photovoltaic array is again adjusted through a range of voltages and the process is repeated. The electric energy and the electric power generated by the photovoltaic array is delivered to the battery which stores the electric energy and the electric power for later delivery to a load.

Electrical power tool having a motor control circuit for providing control over the torque output of the power tool

Abstract: A power tool such as an electric drill typically contains a gear train that couples the output spindle of the motor to the tool bit-receiving chuck The control circuit for the power tool is operable in a ratcheting or pulse mode that causes the output spindle to rotate in discrete incremental amounts Corresponding methods for controlling the operation of the electric motor of a power tool are also disclosed

Overview of biomass and waste fuel resources for power production

Abstract: This paper provides an overview of issues and opportunities associated with the use of biomass for electric power generation. Important physical characteristics of biomass and waste fuels are summarized, including comparisons with conventional fossil fuels, primarily coal. The paper also provides an overview of the current use of biomass and waste fuels for electric power generation. Biomass and waste fuels are currently used for approximately 9800 MW of electric generating capacity, including about 6100 MW of capacity fueled by wood/wood waste and about 2200 MW of capacity fueled with municipal solid waste. Perspectives on the future availability of biomass fuels (including energy crops) are addressed, as well as projected levels of market penetration for biomass power. By the year 2010, there is a potential for from 22,000 MW to as much as 70,000 MW of biomass-powered electric generating capacity in the U.S. Given the range of benefits offered by biomass, including reduced sulfur emissions, reduced greenhouse gas emissions, job creation, rural revitalization impacts, and new incentives under the Energy Policy Act of 1992, the potential use of biomass for power production could significantly expand in the future.

Power control system for a fuel cell powered vehicle

Abstract: A control system interrelatedly controls the electric power output and oxidant supply in a fuel cell electric power generation system. The power generation system comprises at least one fuel cell stack, and a plurality of electrical loads powered by the fuel cell stack, including an electric traction motor for propelling the vehicle, and a compressor for delivering oxidant gas to the fuel cell stack. The electric power output of the at least one fuel cell stack is dependent on the compressor speed. The control system comprises a summing device for determining the total instantaneous power demand of the electrical loads based on a plurality of sensed power demand signals, and a processor for generating a feed-forward output signal for adjusting the compressor speed to a value predicted to give fuel cell power output sufficient to satisfy the instantaneous power demand.

Integrated circuit design automatic utility meter: apparatus & method

Abstract: An automatic utility meter is provided for collecting, calculating, storing and displaying data correlative of consumption of utility commodities such as electric power, gas, water and the like. In addition, the automatic utility meter includes communication means which allows bi-directional communication of data to and from a remote computer. The automatic utility meter is a direct replacement for existing electric utility meters and uses direct read circuitry to sample and calculate power directly from the input voltage and current waveforms received from an electric utility company.

Influence of photovoltaic power generation on required capacity for load frequency control

Abstract: We developed a mathematical model to evaluate the impact of small (rooftop) photovoltaic (PV) power-generating stations on economic and performance factors for a larger scale power system, and applied this model to the Tokyo metropolitan area. We used solar radiation data from five local meteorological stations to estimate both the individual and aggregate contributions of the projected PV stations to the local power grid. We found that an electrical power system containing a 10% contribution from PV stations would require a 2.5% increase in load frequency control (LFC) capacity over a conventional system. The break-even cost for PV power generation was found to be relatively high for contribution levels of less than 10%. Higher proportions of PV power generation gave lower break-even costs, but economic and LFC considerations imposed an upper limit of about 10% on PV contributions to the overall power systems.

Power quality measurements performed on a low-voltage grid equipped with two wind turbines

Abstract: The power quality of a low-voltage grid with two wind turbines is investigated. Slow voltage variations as well as transients and harmonics are measured and analysed. Furthermore, the spectrum of the power is determined so that the presence of periodic power components can be investigated. Although periodic power fluctuations reaching 10% of the rated power are registered, voltage variations are lower than the prescribed IEC flicker limit at steady-state operation. As the turbines are put on-line, the voltage level is lowered by 3%, which exceeds the flicker limit. The risk for flicker increases if the X/R ratio of the grid is low and if turbines which have a tendency to produce large periodic power fluctuations are used.

Exhaust gas-purifying system for internal combustion engines

Abstract: An exhaust gas-purifying system is provided for an internal combustion engine for use in a vehicle having an alternator driven by the engine to generate electric power. An electrically-heated catalyzer is arranged in the exhaust system of the engine and connected to the alternator to be electrically heated thereby. A changeover switch is provided for selectively switching the destination of electric power generated by the alternator to the electrically-heated catalyzer and to the electrical equipment. An ECU controls the electric power generated by the alternator, depending upon a direction in which the changeover switch has been switched. The ECU detects abnormality of the changeover switch, and when the abnormality is detected, the electric power generated by the alternator is changed to a value smaller than a value assumed when the changeover switch is normal.

Hand-carried traffic control light

Abstract: A hand-carried traffic control light having signaling and flashing functions is disclosed. The above light has a cylindrical handle receiving batteries and a switch cap with a multistage switch. A longitudinal LED carrier that is formed of a PCB and has a plurality of openings is electrically coupled to the switch cap. A plurality of LEDs are mounted to the openings of the LED carrier respectively to be selectively applied with electric power of the batteries in accordance with a switching motion of the switch. A reflector and a flashing bulb are held on the holding protrusion of the LED carrier. The bulb is selectively applied with electric power of the batteries in accordance with the switching motion of the switch. A color reflecting tube surrounds the LED carrier. An external tube surrounds the color reflecting tube. A transparent cap is fitted over a top of the external tube to protect both the reflector and the bulb.

Control system for electric vehicle

Abstract: A motor control device for controlling the driving and regenerative operation of a motor includes CPU, ROM, RAM and a back-up RAM. An electric power is normally supplied from a subsidiary battery through a second regulator to the back-up RAM. An electric power is also supplied to the CPU, the ROM and the RAM through a main switch and a first regulator, on the one hand, and through the first regulator and a transistor which is turned ON when the number of revolutions of the motor becomes equal to or larger than a predetermined value, on the other hand. Therefore, even if the main switch is opened during traveling of a vehicle at a high speed, the counter-electromotive force of the motor can be decreased by the motor control device which is supplied with the electric power through the transistor to maintain its function, thereby preventing damage to an inverter.

Control system for electric power generating apparatus on hybrid vehicle

Abstract: An electric power generating apparatus having an electric generator is mounted on a hybrid vehicle which has a propulsive electric motor powered by a battery and an internal combustion engine for actuating the electric generator to generate an electric power output to charge the battery. A goodness-of-fit calculator and a generator operational amount calculator determine an operational amount for the electric generator based on a membership function and fuzzy rules stored in a fuzzy reasoning memory according to fuzzy reasoning from vehicle operating conditions including a charged and discharged condition of the battery and a vehicle speed of the hybrid vehicle, detected by operating condition detectors.

Development of transient stability control system (TSC system) based on on-line stability calculation

Abstract: This paper describes a new transient stability control system named the TSC system developed for application to the trunk power system of Chubu Electric Power Co. (CEPCO). The TSC system prevents wide-area power system blackout by shedding optimal generators when a serious fault occurs. This system has the following features: (1) the TSC system performs detailed stability calculations based on online information telemetered from the actual network, and it periodically evaluates the stability of the power system against contingencies with a high degree of accuracy. The system selects the optimum generators to be shed; (2) if a contingency actually occurs, the generators to be shed that were determined in advance are shed about 150 ms after fault occurrence to maintain the stability of the power system; and (3) the system can be applied to any power system configuration of CEPCO, such as a loop network, radial network, etc. The TSC system will be put into regular service in June 1995. It will be the world's first real-time stability control system that performs detailed transient stability calculations on a large power system online.

Electrical power system

Abstract: An electrical power plant has a rotator means (1) that rotates one or more alternators (6, 8) to generate electrical current that is transmitted to one or more electrical storage bakeries (12, 13) from which electrical current is transmitted to an electrical motor (2) that is a rotational-power component of the rotator means. Electrical current can be transmitted from the one-or-more storage batteries to electrical items such as a vehicle motor (32, 34), electrical appliances, electric lights and electrical communication devices. The rotator means can include a prime mover (10) that can be used for particular applications such as a vehicle (30) engine in addition to rotation of one or more of the alternators.

Modular power distribution system

Abstract: A modular power distribution system is ideally suited for use in modular buildings of the type in which prefabricated building modules are constructed at a manufacturing factory and shipped to a remote building site where the modules are interconnected to form the complete structure The modular power distribution system includes a primary power distribution panel positioned in one of the building modules and is adapted to distribute power from the utility service to the building modules Modular power distribution units positioned in each of the building modules are adapted to distribute power within a respective building module The primary power distribution panel has a plurality of main circuit breakers, each of which is electrically connected between the utility service and one of the modular power distribution units for limiting the maximum current through a respective modular power distribution unit Each modular power distribution unit also includes a secondary power distribution panel which is physically and electrically interconnected with an associated service distribution unit The secondary power distribution panel includes a plurality of secondary circuit breakers, and the service distribution unit includes a plurality of modular electrical connector first portions Each of the modular connector first portions is connected to receive power through a different one of the secondary circuit breakers Each building unit also includes a plurality prewired electrical fixture units Each of the prewired electrical fixture units includes an electrical fixture, a modular electrical connector second portion, and a plurality of electrical conductors extending between the electrical fixture and the electrical connector to transmit electrical power therebetween The connector second portions are electrically and physically mateable with the connector first portions to electrically interconnect the prewired electrical fixture unit with one of the secondary power distribution panel

Comments on active power flow and energy accounts in electrical systems with nonsinusoidal waveforms and asymmetry

Abstract: Pricing of electric energy is based on the value of the integral of the load active power P measured by energy meters. At such a pricing, the electric power utilities waste some revenue for the energy delivered to current harmonic generating customers and/or customers causing current asymmetry. This is because the load generated current harmonics and unbalanced currents cause an increase in the active power loss in the distribution system. At the same time, the customers that do not generate harmonics but are supplied with distorted and/or asymmetrical voltage are billed not only for the useful energy but also for the energy which may cause only harmful effects on their equipment. It is shown in the paper that these two disadvantages of the tariff in single-phase systems could be eliminated if the energy account based on the value of the integral of the active power of only fundamental harmonic, P/sub I/, rather than on the integral of the whole active power P was used. These disadvantages could be eliminated in three-phase systems if the energy account is based on the integral of the active power of the positive sequence component of the fundamental harmonic.

Power management and distribution system for a more-electric aircraft (MADMEL)-program status

Abstract: A complete, and somewhat revolutionary, system design approach is needed to exploit the benefits that a more-electric aircraft can provide. Traditional-mounted auxiliary drives, and bleed air extraction will disappear, to be replaced with integral engine starter/generators and electrically driven actuators and pumps. A five-phase Power Management and Distribution System for a More-Electric Aircraft (MADMEL) program was awarded by the Air Force to Northrop/Grumman Military Aircraft Division in September 1991. The objective of the program is to design, develop, and demonstrate an advanced electrical power generation and distribution system for a More-Electric Aircraft (MEA). The MEA emphasizes the use of electrical power in place of hydraulics, pneumatic, and mechanical power to optimize the performance and life cycle cost of the aircraft. This paper presents an overview of the MADMEL program and a top-level summary of the program results, development and test of major components to date. In Phase I and Phase II studies, the electrical load requirements were established and the electrical power system architecture was defined for both near-term (NT-year 1996) and far-term (FT-year 2003) MEA application. The detailed design and specification for the Electrical Power System (EPS), its interface with the Vehicle Management System, and the test set-up were developed under Phase III. Phase IV, fabrication and testing of the subsystem level hardware, has been completed. The overall system level integration and testing will be performed in Phase V starting October 1997.

Handbook of Electric Power Calculations

Abstract: Electric power engineers and technicians can turn to the revision of this popular handbook for step-by-step calculation procedures for solving over 300 problems commonly encountered in electrical power engineering. Included are calculations for such areas as network analysis, ac and dc machines, transformers, transmission lines, system stability, grounding, lighting design, batteries, and engineering economics. 250 illustrations.

Asynchronous conversion method and apparatus for use with variable speed turbine hydroelectric generation

Abstract: A hydroelectric power generation system (20) generates electrical power for an electrical utilization system (72). A controller (42) obtains a requested output electrical power level from a hydro- turbine unit (70) by using a signal Indicative of water head (h meas) to control speed of an asynchronous rotary converter (50) coupled to the hydro-turbine unit and to control gate position of the hydro-turbine unit. The requested output electrical power level is applied from the hydro-turbine unit via the rotary converter to the electrical utilization system. In one embodiment, the controller (42B) accesses an undatable memory wherein Hydraulic Hill Chart information is stored. In another embodiment, the controller (42C) also includes a real- time automatic governor which uses a signal indicative of ac transmission frequency to the electrical utilization system to control the output electrical power level of the rotary converter.

System and method for providing centralized backup power in a computer system

Abstract: In a computer system having a plurality of electronic subsystems therein adapted to receive main electrical power from an interruptible main power supply, ones of the electronic subsystems being designated as critical to retention of user data in the computer system in an event of interruption of the electrical power from the main power supply, a backup power subsystem and method for controllably delivering backup electrical power to the ones of the electronic subsystems. The subsystem comprises: (1) a central electrical power storage cell having a particular capacity and adapted to be maintained in a constantly charged state, (2) a backup electrical power bus coupled to the central electrical power storage cell and adapted to be selectively coupled to selected ones of the electronic subsystems and (3) a backup power management controller adapted to couple the backup electrical power bus to the selected ones of the electronic subsystems.

Display panel driving circuit

Abstract: A display panel driving circuit includes a plurality of elementary driver circuits each provided for each one of drive electrodes, an electric power recovery common line, an electric power release common line, first and second coils having one end thereof connected to the electric power recovery common line and the electric power release common line, respectively, and a capacitor having one end connected in common to the other end of the first and second coils. Each of the elementary driver circuits includes a first switch on-off controlled to recover a recovery current from a corresponding drive electrode to an electric power recovery line, a second switch on-off controlled to selectively connect the corresponding drive electrode to a low potential power supply line, a third switch on-off controlled to supplying a recovered electric current from an electric power release line to the corresponding drive electrode, and a fourth on-off controlled to selectively connect a high potential power supply line to the corresponding drive electrode. The electric power recovery common line is connected in common to the electric power recovery line of all the elementary driver circuits, and the electric power release common line is connected in common to the electric power release line of all the elementary driver circuits. The first to fourth switches of each of the elementary driver circuits are so controlled that each of the elementary driver circuits can perform the electric power recovery operation and the electric power release operation simultaneously in parallel to those of the other elementary driver circuits. Thus, the electric power recovery/release can be carried out not only in the display cell sustain discharge driving period but also in the display data writing period.

Power and energy

Abstract: Unnaturally splendid weather in Northern Europe and Britain and a stupendous stretch of dry, sunny days in much of the United States were last summer's pointers to the year's weightiest technical development for the electric power sector: the growing confidence among atmospheric scientists in their computer models' warnings that the Earth will warm up markedly over the next century. This paper presents an overview of the power generation-based global warming argument and highlights how: global warming scenarios have gained credibility; international rivalry has quickened in power supply; combined-cycle power plants have attained record efficiencies; and how technical gains have strengthened the renewable energy sector.