Showing papers on "Electricity generation published in 1984"

Power Generation, Operation, and Control

Abstract: Topics considered include characteristics of power generation units, transmission losses, generation with limited energy supply, control of generation, and power system security. This book is a graduate-level text in electric power engineering as regards to planning, operating, and controlling large scale power generation and transmission systems. Material used was generated in the post-1966 period. Many (if not most) of the chapter problems require a digital computer. A background in steady-state power circuit analysis is required.

Combined-Cycle System With Novel Bottoming Cycle

Abstract: A new thermodynamic energy cycle has been developed using a multicomponent working agent. This cycle is designed to replace the currently used Rankine Cycle as a bottoming cycle for a combined-cycle energy system as well as for generating electricity using low-temperature heat sources. Several combined power systems based on this cycle have been designed and cost-estimated. The efficiency of this cycle is from 1.6 to 1.9 times higher than that of the Rankine Cycle system, at the same border conditions. The investment cost per unit of power output for this cycle is lower than that for the Rankine Cycle system in approximately direct proportion to the energy advantage. The application of this cycle as a bottoming cycle in combined-cycle systems involves the use of an energy system which utilizes heat from the exhaust of a gas turbine, resulting in an increase in overall efficiency of up to 20 percent above the efficiency of the combined systems using the Rankine bottoming cycle. As a result, a thermal efficiency in the range of 50–52 percent can be achieved using a conventional gas turbine. The project to build the first experimental installation is now in progress. This installation is to become operational at the end of 1984.

Reliability Modeling of Large Wind Farms and Associateed Electric Utility Interface Systems

Abstract: This paper is concerned with modeling the reliability characteristics in both probability and frequency of large electric utility application wind turbine generators together with their associated utility interface equipment. A computationally efficient algorithm is developed and applied to a wind farm with a special AC/DC/AC interface currently under design. The effects of various wind turbine/interface system component forced outage rates on the expected annual energy output of the farm is examined.

Controls for Variable Pitch Wind Turbine Generators

Abstract: This paper analyzes the control requirements of wind turbine generators connected to electric power systems. The requirements are based on stand-alone as well as interconnected operation. Control systems are developed for wind turbines with synchronous, induction, and doubly-fed generators. Results of detailed, non-linear time response simulation are presented.

Wind Turbine Generator Interaction With Diesel Generators on an Isolated Power System

Abstract: The Block Island Power Company (BIPCO), on Block Island, Rhode Island, operates an isolated electric power system consisting of diesel generation and an experimental wind turbine. The 150-kW wind turbine, designated MOD-OA by the U. S. Department of Energy is typically operated in parallel with two diesel generators to serve an average winter load of 350 kW. As part of an experimental program to evaluate wind turbine generator performance on the isolated diesel power system, the recordings from an extensive data measurement effort were reviewed and analyzed to define the nature of the dynamic interaction effects. The data were collected over a three-month period on the system to which the DOE/NASA experimental wind turbine was connected. During this time, the diesel units were lightly loaded resulting in up to 60 percent of the total load demand being supplied by the MOD-OA in periods of severely gusting winds. In three of the modes of normal MOD-OA operation. startup???synchronization, shutdown/cutout, and continuous fixed pitch running???power, frequency and voltage transients were comparable with those produced by typical load changes on the diesel system alone. In the fourth mode, variable pitch (constant power) control, a significant reduction in system damping sometimes occurred which gave rise to increased frequency and voltage perturbations under gusty wind conditions. Based on a linear model of the system it is shown that changes in control system settings could be made to improve damping.

Control system for run-of-river hydroelectric plant

Abstract: A control system for a hydroelectric power plant of the run-of-river type wherein the load on the turbine-generator units is matched to the flow of the river so that the units operate at the maximum head available for existing flow conditions to produce the maximum energy available from the river flow for the installed capacity of the plant and within the allowable, safe operating capability range of the turbine-generator units. Reservoir water level sensors provide a signals indicative of changing water level, sensors for generator electrical and thermal operating characteristics provide a signals related thereto, and a control connected to the water level sensors, to the generator sensors and to the turbine governor adjusts the turbine flow control devices to change the turbine power in response to changing river level within the safe and allowable operating range of the generator. Adjusting the turbine power to match the water available either when the reservoir level increases or decreases maintains maximum head for the power plant to obtain maximum energy therefrom. A tailwater level sensor and cavitation control also control the turbine flow control devices in an appropriate manner when a condition of cavitation is being approached. The control system typically is employed with a plurality of turbine-generator units in a hydroelectric power plant.

Field Experiences in Reenergization of Electrical Networks from Thermal and Hydro Units

Abstract: The problem dealt with in the paper is the fast return to normal-operation of a generation and transmission power system, after it has experienced a total or partial power failure. The aim is to illustrate the practices adopted in a hydrothermal power system and to present the outcomes and performances verified in some tests and field experiences. Considerations about the influence of the behaviour of the load and of the generating units involved in restoration are also given.

Effects of Voltage Control in Utility Interactive Dispersed Storage and Generation Systems

Abstract: When a small generator is connected to the distribution system, the voltage at the point of interconnection is determined largely by the system and not the generator. This paper examines the effect on the generator, on the load voltage and on the distribution system of a number of voltage control strategies. Synchronous generators with three kinds of exciter control are considered, as well as induction generators and constant extinction angle inverters, with and without capacitor compensation. Operation with a constant slightly lagging power factor is shown to have some advantages.

Electrical energy from the wind

Abstract: A development status and economic feasibility assessment is made for wind turbine electrical energy generation It is noted that the benefits of such alternative power sources as the wind are reduced with increasing market penetration, suggesting that only modest penetrations (of 5-15 percent of total load) may be initially possible There is, unfortunately, little correlation between the timing of strong winds and peak loads Neverthless, blade aerodynamics and structures advancements have significantly improved wind turbine electrical generation economics by lowering minimum operating wind speeds and increasing service life, respectively Attention is given to wind energy fluxes over the US, and the relative performance of NASA-sponsored wind turbine types 12 references

The Themis Program and the 2500-KW Themis Solar Power Station at Targasonne

Abstract: Following the first oil crisis, the French Agency for Energy Conservation (A.E.E.) setup in 1975, devoted its time and efforts towards saving energy both in industry and in housing. This effort was expanded by our government in 1978, when the French solar energy authority, known as COMES, was created: it concentrated on R and D pertaining to new and renewable energy. Early this year, these two agencies were merged together to create the French Agency for the Management of Energy (FAME), which includes geothermal and heat distribution networks. This decision now gives the French government the tool to implement a very ambitious and diversified program, calling at the same time on energy conservation and on new and renewable energies development. An important part of the R and D program set up by FAME is the thermodynamic conversion program. On one side, the program devotes itself to the development of components and systems, among them the THEK program which deals with parabolic dishes. These could be used not only for heat generation purposes or electricity generation but also in stand alone systems, for example to refrigerate and conserve fish, a useful application in the developing countries. On the other side, themore » program calls for the implementation of pilot plants in order to experiment with these components and thermodynamic cycles. Such a pilot plant is nearing completion near Ajaccio in Corsica, and is due for operation early next year. Partial tests have already been run. It was a distributed collector parabolic trough array and a Rankine cycle turbine.« less

Digital Control of Power Transients in a Nuclear Reactor

Abstract: An integrated, closed-loop, control system for online operations in nuclear power plants has been developed and demonstrated with an LSI-ll/23 micro-processor on the 5 MWt fission reactor (NITR-II) that is operated by the Massachusetts Institute of Technology. This control system has inherent capabilities to perform online fault diagnosis, information display, sensor calibration, and measurement estimation. Recently, its scope has been extended to include the direct digital control of power changes ranging from 20-80% of the reactor's licensed limit. This controller differs from most of those discussed in theoretical and simulation studies by recognizing the non-linearity of reactor dynamics, calculating reactivity on-line, and controlling the rate of change of power by restricting both period and reactivity. The controller functions accurately using rods of non-linear worth in the presence of nonlinear feedback effects.

Wind Power Technology

Abstract: In this article Dr R H Taylor discusses the technology of modern wind turbines, including the design options, recent advances and the research needs for this evolving industry. He concentrates on the larger machines for electricity production, summarising the status of various projects around the world and assesses how much further wind energy has to go before it can compete with more conventional forms of energy conversion

Gas concentration cells for utilizing energy

Abstract: An apparatus and method for utilizing energy, in which the apparatus may be used for generating electricity or as a heat pump. When used as an electrical generator, two gas concentration cells are connected in a closed gas circuit. The first gas concentration cell is heated and generates electricity. The second gas concentration cell repressurizes the gas which travels between the cells. The electrical energy which is generated by the first cell drives the second cell as well as an electrical load. When used as a heat pump, two gas concentration cells are connected in a closed gas circuit. The first cell is supplied with electrical energy from a direct current source and releases heat. The second cell absorbs heat. The apparatus has no moving parts and thus approximates a heat engine.

Real Time Simulation System Of Large-Scale Power System Dynamics For A Dispatcher Training Simulator

Abstract: Individual generator dynamic calculation method is tused in simulating severe power system disturbances, such as system separation due to faults or resynchronization. To speed up the sparse matrix calculations, a new vector processor was developed which made it possible to perform real time dynamic calculations for a large-scale power system. Test results proved that dynamics of a system with 186 buses and 44 generators could be calculated within one-third of the actual phenomenon time.

Waste heat recovery from diesel engines

Abstract: Technical developments continue in the direction of successfully converting heat energy of low availability to mechanical energy. It is therefore more likely that future ships will make increasingly use of waste heat recovery arrangements. Two applications are of main interest: heating (fuel oil, water, air-conditioning etc.) and electricity generation.

Geothermal hot water transportation and utilization system

Abstract: Disclosed is a system for transporting geothermal hot water taken up at an underground bottom portion of a geothermal production well up to the ground surface, efficiently with a loss suppressed to minimum of the energy possessed by the geothermal hot water, which comprises a downhole pump disposed at an underground bottom portion of the geothermal production well for taking up and pressurizing the geothermal hot water and a rotary separation two-phase flow turbine adapted to be driven by the transported geothermal hot water, the downhole pump being adapted to be driven by the rotary separation two-phase flow turbine Also disclosed is a system for utilization of underground geothermal hot water, which comprises a downhole pump disposed at an underground bottom portion of a geothermal production well and a rotary separation two-phase flow turbine for pressurizing geothermal hot water taken up and supplied thereto by the downhole pump and supplying pressurized geothermal hot water to a direct contact heat exchanger so as to generate power through the medium of a low boiling-temperature medium, while at the same time separating and supplying steam to a steam turbine to generate power, whereby a power generation by a binary cycle is carried out

Electrochemistry of fuel cells for transportation applications

Abstract: Fuel cells are promising power sources for electric vehicles and do not suffer from the inherent limitations of efficiency, energy density, and lifetime, as encountered with all types of batteries considered for this application. The projected performance of fuel-cell vehicles is comparable to that of the internal combustion and diesel engine vehicles but with the additional advantages of higher fuel efficiency, particularly with synfuels from coal. The ideal fuel for a fuel-cell power plant for electric vehicles is methanol. This fuel is reformed to hydrogen, which combines with oxygen from the air in an acid electrolyte (phosphoric, solid polymer, or superacid) fuel cell to produce electricity. Though the phosphoric acid fuel cell is in the most advanced state of development (mainly for power generation applications), the solid polymer and superacid electrolyte fuel cells are more promising for the transportation application because of the faster oxygen reduction kinetics (and hence potential for higher power densities) and shorter start-up times. Alkaline electrolyte fuel cells can be used only with pure hydrogen which causes a weight or energy penality for any of the methods it can be carried on board the vehicle), but have the best potential for minimizing or eliminating noble metal requirements. The paper summarizes needed areas of research (i.e. reduction or elimination of noble metal loading, finding CO-tolerant electrocatalysts, finding less expensive solid polymer electrolytes, synthesis and elucidation of higher molecular weight superacids) to advance fuel-cell technology for vehicular applications.

Evaluation of Grid-Connected Inverter Power Systems: The Utility Interface

Abstract: Dispersed electrical generation connected into the U.S. utility grid is a promising way to increase energy production. However, to assure technical compatibility of the grid and potentially large numbers of these small generation sources, an engineering evaluation effort is required. Work is presented that is currently under way to test inverter power systems in a grid-connected environment. The technical details of the tests related to utility interface and of the special equipment required to conduct them are described. Results from testing grid-connected inverters for photovoltaic applications will be examined.

Cogeneration microwave food dryer

Abstract: An energy efficient dryer for solid foods with moist interiors uses both thermal convective and microwave drying processes. The dryer will run on a fuel such as natural gas alone, and requires no input of electricity because it utilizes a single prime mover to produce both thermal energy and electrical energy, such as an internal combustion engine, which both provides heat for convective drying, and drives a generator which produces electricity for conversion to microwave power. Moist food is fed by an air pervious belt or other means through a first zone in which it is dried by thermal convection, and then through a second zone in which it is dried by microwave radiation.

Investigation of the Torsional Performance of Superconducting Generators with an Advanced Network-Torsion-Machine Program

Abstract: The significant potential advantages of superconducting generators have stimulated large-scale efforts throughout the world to develop such generators for utility application. A thorough study of the transient performance of superconducting generators requires improved generator modeling in an efficient program for power system dynamics to adequately represent the highly complex interaction of the generator multi-damper system with the network. A novel approach to this task is presented in this paper. It consists of an advanced network-torsion- machine program to analyze electromagnetic and electromechanical transients in which iterative (repeatedly connected) T-network equivalent circuits for the generator d-q model have been integrated [1]. The capability of this program is outlined and demonstrated by a spectrum of various system disturbances imposed on a large superconducting generator. First results are discussed and highlight particular design considerations of superconducting rotors for improved transient performance.

Method of and apparatus for shaft power generation

Abstract: A method of shaft power generation includes: a step of dividing mechanical power taken out from a main engine into two portions for respective systems; a step of inputting one of the portions of the divided mechanical power directly to a differential planetary gear mechanism; a step of inputting the other portion of the divided mechanical power to the differential planetary gear mechanism through a subsidiary generator, a thyristor or transistor controller and a thyristorized or transistorized motor, each of which has a capacity which is equal to a value obtained by adding a slight allowance to a value obtained by multiplying the capacity of a main generator by the ratio between, on the one hand, a value obtained by the difference between the lowest and highest number of revolutions of the main engine of the range within which the mechanical power therefrom is employed for power generation and, on the other hand, the highest number of revolutions, thereby combining into one the two portions of the divided mechanical power; and a step of driving the main generator at its rated number of revolutions by the combined mechanical power output from the differential planetary gear mechanism.

The effects of fuel and electricity prices on cogeneration in the pulp and paper industry

Abstract: Economic theory indicates that a cost-minimizing firm's decision to cogenerate electricity reflects the interaction of a variety of economic and technological variables. The paper presents a simple theoretical model that illuminates these interactions. The model shows how cogeneration decisions are affected by fuel prices, electricity prices, capital costs, and steam load characteristics. Data for the pulp and paper industry are used to test this theoretical model. The empirical results indicate that the model is broadly consistent with actual firm behavior in this industry. The supply of cogenerated electricity in the pulp and paper industry varies directly with electricity prices and inversely with fuel prices. However, the estimated supply of elasticity within the range of the data is fairly small.

Steam Temperature Prediction Control for Thermal Power Plant

Abstract: An advanced control method using a microprocessor is developed for boiler steam temperature control of thermal power plants. A process dynamics model with the Kalman filter in the controller is presented which describes the dynamic plant behavior. Using the model, future changes in steam temperature are predicted and the fuel flow rate compensated accordingly. The model is also used to adjust the control parameters, i.e. proportional and integral gains, to provide values which ensure stable system control.

The Power Game—the Development of Conventional Power Stations 1948–1983

Abstract: The paper traces the development of conventional power stations and associated systems of the Central Electricity Generating Board (CEGB) over a thirty-five year period. During that time turnover increased by a factor of over thirty, unit capacity by a factor of twenty, whilst the installed capacity increased almost fivefold. Early difficulties with large high-pressure units are described and the measures taken to overcome them, leading to current high levels of performance. To support these developments, the CEGB has built up a powerful engineering and scientific capability and has accumulated a wealth of experience in the solution of power station problems. Operation and maintenance techniques have been developed to a high degree. The paper also outlines the changes in the organization of electricity generation in the UK which have occurred in response to changing circumstances.

Total planning of combined district heating, cooling and power generation systems for a new town—Part I

Abstract: The objective of this study is to introduce one of the main results of the project for studying energy conservation technologies in a new airport town, which is organized by the Osaka Science and Technology Center, Japan. First, based on the estimated energy demands in the new town, technological aspects are investigated for the district heating, cooling and hot water supply system. Then, the economic and energy saving characteristics are compared for several alternative systems according to the differences of the type of absorption refrigerating machine and so forth. Assuming that a combined heat and power plant is used as the heat source plant of the district thermal distribution system, the optimal combined district heating, cooling and power generation system has been selected from a comprehensive economic viewpoint. Lastly, it is ascertained that if fuel costs continue to rise at the rate of 8 per cent per year, the best energy conservation system becomes superior economically to the conventional district thermal distribution system.

Experience and Recent Development with Gas Directly Cooled Rotors for Large Steam Turbine Generators

Abstract: As recently as ten years ago, projections of ever increasing unit ratings spurred development efforts toward improved cooling systems for generator rotors. Today, however, the concern of the power generation industry is focused on reliability and efficiency rather than on rating growth. Consistent with these concerns, gas- cooled two-pole rotors with diagonal flow ventilation and gas- cooled four-pole rotors with radial flow ventilation have provided reliable and efficient performance. In addition, development programs set in motion in the early 70' s, prior to the reduction in projected unit ratings, have demonstrated that further improvements in efficiency, as well as rotor thermal capability, can be attained with gas-cooled rotors. This proven capability will provide for the needs of the power generation industry both today and in the foreseeable future.