Showing papers on "Base load power plant published in 1992"

The power of self-esteem

Abstract: Describes the ways that ordinary families fail to develop self-esteem and self-acceptance in children, and suggests techniques for adults to do so on their own.

Microprocessor-based boiler controller

Abstract: A microprocessor-based sequencer for a multiple boiler heating system which allows the plural boilers to operate in a base load mode whereby one or more boilers can be made to operate at their optimum operating points and as the heating demand changes, a swing boiler accommodates the change, leaving the other(s) at their Preferred Load value until the swing boiler can no longer satisfy the demand change. At this point, the sequencer adjusts the base load level away from the preferred load set-point.

Real-time economic load allocation

Abstract: The method allocates a demanded amount of power to a plurality of power output apparatus, each power output apparatus having a cost curve associated therewith, such that each of the power output apparatus supplies a portion of the demanded power, and the total power outputted from the plurality of power output apparatus being optimally cost efficient. Data is entered for each of the power output apparatus into a controller. Solutions are generated for all possible output power demands using an optimization by parts technique within output power bounds of each of the power output apparatus. The solutions indicate the portion of power each power output apparatus is to supply to provide the total power demanded at the optimal cost efficient. The solutions are stored in tables within a storage unit of the controller. Upon receipt of a demand for power, a search is performed of the solution tables to obtain the amount of power each power output apparatus is to supply to meet the demand. Control signals are then outputted to each of the power output apparatus, the control signals being indicative of the amount of power to be supplied.

Power demand control

Abstract: A system and a method for saving power of an output variable apparatus such as an inverter air conditioner. A power demand controlling system includes: a power demand controlling unit for detecting and monitoring constantly an electric current flowing through the domestic lines; and power save controlling unit, connected to the domestic power lines and the output variable apparatus, for sending a power save signal to the apparatus, based on the current monitored by the power demand controlling unit, so that an output of the apparatus is reduced to a minimum value and after the power save signal is cancelled the output is returned gradually and stepwise to an original value.

A power electronics based power shedding control for wind/diesel systems

Abstract: SYNOPSIS The use of power shedding (or dump load) control in wind-diesel systems represents a method to ensure stability of the electrical network or to maintain a minimum load on the diesel(s). One approach to dissipate excess power is the use of an electronically controlled electrical load. This paper describes a simple, effective, low cost, and reliable power shedding control system that was designed and built as part of the University of Massachusetts Wind/Diesel System Simulator. The power electronics design, which is based on pulse width modulation, requires only one active switching device, and a single resistive element. In its present form, the capacity of the device is 10kW. Scaling, however, to a larger capacity should not present significant problems. As described in the paper, tests undertaken with the dump load control show that it can successfully maintain grid frequency, has acceptable harmonic distortion, and can ensure a minimum load on a diesel generator. In addition, the dynamic respon...

Advanced Drive Systems and Infrastructure for Electric or Hybrid Buses, Vans and Passenger Cars (I)

Abstract: SummaryFor the nexl two decades a strong growth of the transportation sector is still to be foreseen, at least 40% by 2015. Not only the infrastructural consequences but also the environmental impacts are dramatic. Therefore, efforts are being developed that strive for reduction of private transportation in favour of public transportation. Another option for a further reduction of the emissions in the inner cities is the substitution of conventional vehicles by an electrical transportation system. The large-scale introduction of such a system has a substantial impact on the electricity distribution network and a positive impact on the electricity production. It extends the load levelling effect of night rechargers and uses the base load units better. But electrical transportation is not the only way to reduce the pollution by exhaust gases. Many efforts for developing internal combustion engines with low consumption are taking place for some years and in this respect another of the further options is the ...

Apparatus for interrupting supply of power from power system to portion of consumer load in response to control signal from power system

Abstract: A consumer load receiving power from a power system is divided into a first load to which power may be interrupted if necessary to reduce demand on the power system, and a second load to which power supply may not be interrupted to reduce demand on the power system. When it is necessary to reduce demand on the power system, the power system sends a load control signal to a controller at the consumer indicating that supply of power to the first load is to be interrupted. In response to the load control signal, the controller interrupts supply of power from the power system to the first load, thereby reducing demand on the power system.

Supply of geothermal power from hydrothermal sources: A study of the cost of power in 20 and 40 years

Abstract: This study develops estimates for the amount of hydrothermal geothermal power that could be on line in 20 and 40 years. This study was intended to represent a snapshot'' in 20 and 40 years of the hydrothermal energy available for electric power production should a market exist for this power. This does not represent the total or maximum amount of hydrothermal power, but is instead an attempt to estimate the rate at which power could be on line constrained by the exploration, development and support infrastructure available to the geothermal industry, but not constrained by the potential market for power.

Availability Analysis of Three Different Types of Combined Cycle Power Plants

Abstract: The goal of power plants with higher efficiency and lower environmental risk than conventional power plants has produced three types of combined cycle power plants. These are: 1) the conventional combined cycle (CCC) power plant, 2) the pressurised fluidised bed combustion (PFBC) power plants, and 3) the integrated gasification combined cycle (IGCC) power plants. The efficiency of the CCC power plant has been sufficiently improved so that it is higher than the conventional power plant. Due to high combustion temperature in the gas turbine, the problem of NOx arose. Different NOx reduction techniques were adopted, such as steam or water injection, and dry low-NOx combustors. Strict environmental regulations in various countries were still violated. Therefore, the selective catalytic reduction (SCR) was installed in the waste heat boiler. Due to design of the CCC power plant, there is still risk of high NOx emission with a simple-cycle operation of the gas turbine. If the simple-cycle operation is not permitted then the effectiveness (energy availability) of the plant deteriorates. The PFBC and IGCC are new rival technologies. Both have a potential for higher efficiency and lower environmental risk than pulverized coal fired (PCF) power plants. These benefits will be lost if the effectiveness of these plants does not compete with the effectiveness of PCF power plants. Backup fuel can be utilized to improve the effectiveness of an IGCC power plant. Improving the effectiveness by using backup fuel involves increased cost for the fuel. If the gas turbine is operated as a simple-cycle with a backup fuel, then the problem of high NOx emission arises, as for the CCC power plant. Differently designed combined cycle power plants have been analysed to investigate the effects of reserve capacity (active redundancy) and repair policy. The Markov process has been used for the analysis and the following results were obtained. 1. The CCC power plant with an appropriate reserve capacity and a suitable repair policy can be chosen to obtain greater effectiveness of the plant with less NOx emission. 2. The effectiveness of PFBC power plants can potentially compete with the effectiveness of PCF plants. With an appropriate reserve capacity or double repair crew policy, the effectiveness of PFBC power plants can be even higher than that of the PCF power plants. 3. With an appropriate reserve capacity and with double repair crepolicy, the effectiveness of IGCC power plants can be improved to equal the effectiveness of PCF power plants. 4. The PFBC power plants have more potential for higher effectiventhan IGCC power plants without backup fuel. 5. The use of appropriate reserve capacity and a suitable repair minimize the use of backup fuel and NOx emissions and, at the same time, improve the effectiveness of integrated gasification combined cycle power plants.

Probabilistic power bus loading analysis for Space Station Freedom

Abstract: The Space Station Freedom's electrical power system is an isolated electric power generation and distribution network with limited generation capability to meet the demands of various housekeeping and experiment loads. A statistical method is developed to determine the power bus loading under normal operating conditions to ensure the supply meets the demand at each bus. The load probability density functions and probability distribution functions were calculated based on the probability of load operation. The probability that a particular load is operating is based on the load's duty cycle. The probability density function is defined as the probability that the power demand at a bus is at a specific power level. The probability distribution function is defined as the probability that the power demand at a bus is below a specific power level. The results indicate that the 12.5 kW power bus is adequate for Lab-A power loads and the 3 kW power bus to the pressurized logistics module is adequate. >

Optimum size of thermal power stations

Abstract: It is well known that the price per unit of generated electrical energy decreases with increasing size of the generator, which implies longer transmission lines and hence larger transmission losses. Considering both these facts, the optimum size of a thermal power station has been obtained by using life-cycle costing analysis; the demand is proposed to be met by a base load generator and a peak load generator. The dependence of the investment ratio (the ratio of present worth of net income to the capital investment) on relevant parameters has been studied. It is seen that there exist optimum sizes of base load generator and peak load generator of a power station, for a given load density. The effect of electricity price, coal price and escalation rates on the optimum sizes has also been investigated. The analysis has been made for constant demand as well as for growing demand. The effect of the ratio of base load to peak load on the economics has also been investigated. The cost data from a recent study in India have been used.

Second-Law Analysis of a Compressed Air Energy Storage (CAES) System

Abstract: Compressed Air Energy Storage (CAES) system consumes excess energy from base load steam power plant, converts it into stored pneumatic energy and then releases it during peak load period through a gas turbine.A comprehensive analysis of exergy flows, inputs, outputs and losses in the entire (CAES and steam plant) system is carried out. The irreversible losses and the system efficiency are more realistically presented, than according to the conventional first-law analysis.Various CAES system schemes and cycle characteristics are studied. It is shown that in some cases the overall thermal efficiency is higher in the combined CAES-Steam Plant System, than in an industrial gas turbine.Copyright © 1992 by ASME

Fast-track, low-cost construction starts with the owner

Abstract: As we approach the threshold of a new round of ordering of base load generating capacity after a 15-year hiatus, power pant owners are taking a long, hard look at construction. The last round of base load construction was plagued with construction cost overruns and delays. Billions of dollars in cost overruns, many attributable to construction delays, were not allowed to be placed in utilities' rate bases. Those problems will not be tolerated in the next round. During the past few years the construction climate has changed. Non-utility power producers have demonstrated and ability to build small power plants-including many steam plants burning solid fuels-quickly and at surprisingly low costs. In this paper the cost-plus approach traditionally taken by more utilities, who will lead in the base-load construction phase, is being seriously questioned.

New control systems will use advanced instrumentation

Abstract: This paper reports that state-of-the-art control systems will help to improve a plant's flexibility while enhancing its life. Wide integration of power plant control systems is the aim of control engineers. However, standard network interfaces must be developed before this can be achieved. In addition, if future control systems are to be truly state-of-the-art, advanced instrumentation and sensors and predictive controls must be utilized. Using advanced control systems makes it possible to improve the operation flexibility and enhance the life of power plants, says the Electric Power Research Institute (EPRI). To meet these goals, EPRI is implementing a series of programs in conjunction with electric utilities and equipment vendors. One of these programs involves developing predictive controls and another is studying plantwide automation. Fossil power plant engineers who are changing their units from baseload to cycling operation must rethink their operating philosophies. The faster loads are changed, the less fuel is used. Unfortunately, cycling of units and/or fast load changes can subject key power plant components to thermal stress. However, power plant optimization programs can eliminate such risks.

An integrated non-fossil fuel electrical power system

Abstract: The authors describe an integrated nonfossil-fuel electrical power system (NFFPS) developed on a farm at Loughborough, England. They investigates the performance and economic viability of the system, both for electrical energy consumption on the farm and for export to the national electricity grid for supply to other consumers. The performance of the system was monitored over a one-year period, to take account of climatic variations during the different seasons. Results obtained are discussed, together with the economics of the system and the development of control strategies to optimize the profit/energy ratio. The NFFPS described uses well-proven items of plant. No significant teething problems were encountered, and, of the 60 MWh of energy produced annually, almost 80% is exported to the national grid.

S J. Fu

Abstract: The Space Station Freedom's electrical power system is an isolated electric power generation and distribution network with limited generation capability to meet the demands of various housekeeping and experiment loads. A statistical method is developed to detennine the power bus loading under nod operating conditions to ensure the supply meets the demand at each bus. The load probability density functions and probability distribution functions are calculated based on the probability of load operation. The probability that a particular load is operating is based on the load's duty cycle. The probability density function is defined as the probability that the power demand at a bus is at a specific power level. The probability distribution function is defined as the probability that the power demand at a bus is below a specific power level. The results indicate thatthe 12.5-kW power bus is adequate for Lab-A power loads and the 3-kW power bus to the Pressurized Logistics Module (PLM) is adequate.