Showing papers on "Stand-alone power system published in 1989"

Integrated circuit apparatus including static electricity protection circuit

Abstract: An LSI includes two internal circuits connected to different power sources, and conventional static electricity protection circuits, provided for connecting input terminals of the internal circuit connected to one power source and for connecting output terminals of the other internal circuit connected to the other power source The LSI further includes two static electricity protection circuits each having an enhancement type field effect N channel MOS transistor provided for connecting the power source and the other power source Thus, a potential rise or a potential fall on one input/output terminal of the internal circuit connected to the power source, which has static electricity applied with respect to the other power source as a reference, is transmitted to one of the new static electricity protection circuits through the conventional static electricity protection circuits connected to the above input/output terminal This transmission of the potential rise or fall then causes the enhancement type FET of this new static electricity protection circuit to be rendered conductive Accordingly, a current path is established between the above input/output terminal and the other power source, so that the static electricity applied to the above input/output terminal is absorbed in the other power source

Optimizing combined cogeneration and thermal storage systems: an engineering economics approach

Abstract: A computer program has been developed to minimize the present worth of the electric and thermal energy costs of a manufacturing facility as a function of the type and amount of cogeneration and thermal storage it might install. The model is particularly useful in instances where the rates paid for electricity are differentiated by time of day and season. The program has been applied successfully to two large industrial facilities located in the southern United States. It simulates the optimal electricity production and thermal energy usage patterns as a function of the equipment installed in the plant over a planning horizon of 15 years, based upon a year's worth of historical data, projected load growth, and projected rates for fuel and electricity. The historical data consists of bihourly information on total electricity consumption and central station chiller electricity usage, as well as bihourly data on the plant's process steam load. Figure 1 shows a generic industrial plant with an electricity feeder and a gas or fuel oil pipiline providing the energy needs with no thermal storage or cogeneration activity. Typically, the electricity is used for a variety of purposes, including motor drive, lighting, and other processing needs. Often, especially in the summertime, electrically driven chillers are a significant portion of the overall electricity demand. The chillers are shown in the figure as a source of cold water for the plant.

Generation, Distribution and Utilization of Electrical Energy

Abstract: This book gives an up-to-date account of electric power generation and distribution (including coverage of the use of computers in various components of the power system). It describes conventional and unconventional methods of electricity generation and its economics, distribution methods, substation location, electric drives, high frequency power for induction and heating, illumination engineering, and electric traction. Each chapter contains illustrative worked problems, exercises (some with answers) and a bibliography.

Control of power quality in modern industry

Abstract: It is noted that utilities cannot provide a continuous, undistributed supply of electricity to sensitive electronic systems. These will occasionally fail without proper power conditioning. Services the utility can and cannot provide in terms of high quality power are identified. Techniques available to control power disturbances inside the plant are explored. It is noted that the uninterruptible power system can solve almost every power quality problem. >

Energy Storage Emerging Strategies for Energy Storage

Abstract: Electricity is produced instantly in response to customer demand. This is a fundamental principle guiding the production and supply of electric power-and one that sets electric utilities apart from other businesses. Unlike most other commodities, electrons aren't bottled or boxed, placed in a warehouse when demand is low, and then dispensed when demand increases. With no \"inventory\" to draw on, utilities have very little leeway in managing production and supply.

The Electricity Supply

Abstract: The production of electricity; three-phase electricity; distribution of electricity; the supply to a premises; lighting and power circuits; sockets and plugs; earthing and double insulation; fuses

New metering and reading techniques based on a modular design concept

Abstract: There is a general trend towards a multi-tariff system of measuring electricity at different times during the day or year for direct, short-distance or remote communication. Thanks to modern electronics, these functions can be carried out in an economical and reliable way by the integration of a maximum number of components into special circuits and by using surface-mounted components. This leads to a reduction in dimensions, so that the size of the apparatus is acceptable. The measuring of energy, combined with the above mentioned functions, is effected similarly by a maximum concentration of the metering elements within a high-integration circuit. Since the requirements of the electricity boards are very varied, the separate functions are carried out by complementary modules. These devices transmit locally or remotely messages which enable the customer to regulate his electricity consumption and assist the electricity board in controlling the network load. >

Battery power storage system

Abstract: PURPOSE: To improve power supply, safety and system efficiency during power interruption or faults, by providing a power interruption countermeasure for a main power system and a reverse flow countermeasure upon occurrence of a fault to an inverter type power storage system which stores midnight power and discharges power at a peak demand. CONSTITUTION: A system shown by a solid line 3 is a main system for feeding power directly from a substation 2 to a load 7 and the system shown by a dot and dash line 8 is a power storage system. Midnight power is charged through inverter 13, 14 into a battery 15. When base power of the main system is insufficient in day time, battery power is fed through the inverters 13, 14 to the loads 7, 20. Upon occurrence of fault in the power supply system, circuit breakers 18, 19 for an uninterruptible power system 17 are turned ON, OFF respectively and power stored in the battery 15 is fed to the uninterruptible load 20. Reverse power flow from the battery 15 to the main system 1 is prevented through operation of a reverse power flow detector 5 which causes interruption of a main system inlet circuit breaker 4 and instantaneous interruption of the main system. COPYRIGHT: (C)1991,JPO&Japio

A knowledge-based approach to optimize the supply and usage of electricity onboard the Space Station

Abstract: During about one third of the Space Station's orbit the solar array output is zero and the payload is served by storage devices It has been found that when a 24-hr cycle is used, some loads onboard the station cannot be scheduled during the desired times It therefore becomes necessary to reduce the cycle length and dispatch period so that a greater number of loads can be served without increasing the size of the power source An approach to optimize the supply and usage of electricity over a shorter time frame is discussed Supply/demand windows of various lengths are implemented for the typical load profile As a result fewer rescheduling tasks are needed and a closer match between the supply and demand is obtained The optimal supply/demand can be refined in terms of the excess and shortage of electricity This technique is implemented using PROLOG and FORTRAN >

Integration of customer-owned generation into the electric utility load dispatching technique

Abstract: The authors discuss the integration of customer-owned generation into the electric utility generation dispatch. They show how high-resolution load and generation data can be used to closely match the supply and demand of electricity, thereby reducing the capacity requirements and overall operating cost. This technique is especially valuable when the customer-owned generation is intermittent in nature, as is the case with photovoltaics. The authors study the load, system generation, and photovoltaic output data for an electric utility in Virginia. The impacts of various levels of photovoltaic (PV) generation on various types of days, e.g. low, medium, and peak load, are shown. It is seen that large amounts of photovoltaic energy do not automatically displace high cost peaking generation. As the peaking generation (e.g., combustion turbines) cannot always change fast enough to accommodate the variable PV generation, the impact is felt on other dispatchable units as well as on hydro and pumped storage. A technique is provided which allows the optimum commitment of hydro, pumped storage, and large fossil units to maximize the utilization of customer-owned generation (such as PV) while keeping the overall cost down. >

Power for development-electricity in the Third World

Abstract: Electrical power is a vital prerequisite for any modern economy. Even in the least developed countries, the availability of a reliable power supply at reasonable cost is important for economic growth and development. The critical issue is that the demand for electrical power in developing countries keeps expanding faster than the growth of supply, which is constrained by financial, technical and manpower-related impediments. The author describes this issue in detail. Many developing countries' power systems suffer from unbalanced investments, with overcapacity in generation coexisting with serious underinvestment in distribution. The author discusses the ways in which these problems can be overcome.

Cost of Electricity

Abstract: Fuel costs are a major component of electricity prices because the cost of generating electricity is the primary determinant of electricity prices. The cost of generation makes up nearly 60 percent of the retail price of electricity, according to the federal Department of Energy’s Energy Information Administration. Fuel is the electricity industry’s largest single expense. Coal and natural gas are the fuels used to generate almost 70 percent of the electricity in the U.S.

Battery Power for Buildings

Abstract: Battery Storage Plant (BSP), which results from recent innovations, makes an interesting proposition for incorporation with a building's electricity supply. Not only can a BSP offer an Uninterruptible Power Supply (UPS), but it can provides savings with the building's electricity costs. Economic considerations and diagrams of a BSP are provided.

Economic analysis of wind‐generated electricity in remote areas of South Africa

Abstract: Costs of wind-generated electricity from a stand-alone wind generator with a two-day autonomous battery storage are compared with costs of diesel-generated and grid electricity for a remote outpost in a game reserve in South Africa. Comparative inflationary costs for diesel and wind were 53 and 33c/kWh, respectively. The cost of connecting to the national electricity grid were estimated to be 248c/kWh. Analysis of the availability of the wind and related power output of a selected wind generator revealed that the wind speeds fell between cut-in and cut-out speeds for approximately 80% of the time. In the light of the positive nature of these preliminary computations it is contended that a combined wind-diesel system, in which the diesel would act as backup storage, would be an economically viable mode of electricity generation in a remote area.

Refitting a major microwave radio system with photovoltaic power supplies

Abstract: The authors report on the planning and implementation of a solar refit program on part of the Panaftel microwave system in West Africa, linking Senegal, Mali, Burkina Faso, Niger, and Benin. It is concluded that in spite of the high initial capital cost, conversion from fuel-dependent power systems to photovoltaic (PV) systems on major microwave routes can be economically sound. The main saving is in fuel cost. Although routine and emergency maintenance will in all probability be reduced, overall maintenance expenditures may not be very different between fuel-dependent systems and PV systems. This is due to the high cost of periodic replacement of aging batteries that is necessary. The effect of conversion on telecommunication system availability is positive, although it was not possible to quantify this factor due to other improvements being introduced during the same time frame. A simplification of maintenance power requirements is foreseeable with the introduction of PV systems. >

Advanced Underwater Power Systems

Abstract: With the advent of new computers and artificial intelligence comes the capability to perform many underwater tasks automatically. Unmanned machines can perform hazardous underwater work for long periods, more economically, and with less risk than comparable manned systems. Typically the power demand for both artificial intelligence and propulsion systems is very high in the underwater environment. In addition, some stationary power systems need to operate unattended for up to 10 years. As the capability of artificial intelligence increases we expect the demands for both power and endurance to increase even more. Current non-nuclear power supplies for underwater systems have limited applicability because they have low specific power and energy density, are unsafe, or are very expensive to purchase and operate. Thus, new non-nuclear systems with greater capabilities are needed in order to fully exploit the potential of unmanned systems. A long endurance underwater power system has been under investigation at Boeing since 1985. The objective of this program is to develop a power system capable of providing at least 1000 kilowatt hours of energy, and capable of operating continuously for more than 10 days. A number of systems are capable of meeting these requirements. The performance of power sources using artificial gills, cryogenic oxygen storage, chemical energy storage, and advanced batteries are compared. The relative merits of each system are discussed for different mission requirements.

Domestic remote-area power supplies: modeling battery usage for energy storage

Abstract: The authors report on the development of methods for simulating the typical operating duty cycle of lead/acid batteries in remote area power supply (RAPS) systems. In developing test cycles for batteries, a RAPS computer simulation program called SOLSIM was used. The structure of SOLSIM and the effect on overall RAPS performance of the variation in key system and control algorithm parameters is discussed. The approach results in the derivation and application of battery load-current profiles for assessing the performance of both prototype and commercial lead/acid batteries. >

The introduction of space technology power systems into developing countries

Abstract: Between 1978 and 1984, NASA-Lewis was responsible for the design, fabrication, installation and operational support of 57 photovoltaic power systems in 27 countries. These systems were installed in locations not served by a central power system and ranged in size from 40 W for powering street lights to 29 kW for providing power to a complete village. Several of the system projects had socio/economic studies components that provided for an assessment of how the introduction of both electricity and a novel high technology power system affected the users and their society.

Installation for electrical power distribution in a building, in the case of an end user

Abstract: The invention relates to an installation for electrical power distribution in a building having an end user, such as domestic premises, a business, having a permanently installed electricity mains power supply which is operated at the normal mains voltage, for example 220 volts, having an electricity supply cable with a meter, distributor, overcurrent protection apparatuses, cables mounted on the surface and/or under the plaster, junction devices, plug sockets and switches, as well as a further electricity mains power supply which is operated at a low voltage, for example 60 volts or less.