Showing papers on "Base load power plant published in 1999"

Dispersed generation impact on distribution networks

Abstract: The insertion of dispersed generation into existing electric power systems has a great impact on real-time operation and planning. Several uncertainties characterize the ability of the existing power system to integrate this form of generation, Hence, dispersed generation must be taken into consideration in power system performance so that operation and security are not disturbed. Dispersed generation increases the complexity of controlling, protecting and maintaining power distribution systems. This article focuses on some technical aspects, but not on the impact on the quality of supply and on tariff signals.

Power conditioning apparatus with energy conversion and storage

Abstract: A method and apparatus for power conditioning and for storing electrical energy, fossil fuel energy, or both in the form of a compressed gas which may then be used in combination with a fossil fuel to generate conditioned electrical power is disclosed. The present invention provides a method wherein the energy so stored is used as a back-up power source to assure uninterrupted conditioned electrical power in the event of a failure of a primary electrical power source. Turbine rotors are maintained in rotation to provide a spinning reserve in that the inertia of the turbines can be used to generate power in the event of minor power disruptions, and the turbines can be powered for producing power in the event of greater power disruptions. The present invention provides an apparatus that enhances the flexibility and efficiency of a power consumer and the internconnected power providing system by allowing the user to have an efficient spinning reserve of power, by providing the capability of a user to shape the load, thereby reducing the spinning reserve requirement of the interconnected system, and to sell excess power and to control transportation costs. Since the present invention allows a user to purchase power from the most efficient source, the present invention promotes efficiency throughout the power generation and power transportation industry.

Load controller and method to enhance effective capacity of a photovoltaic power supply

Abstract: A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The renewable supply may comprise, for example, a photovoltaic power supply or a wind-based power supply.

Incorporation of wind power in the east Danish power system

Abstract: This paper gives an overview of some of the phenomena which will occur in a power system with a large amount of wind production Some of the problems occur due to the induction generators used in the windmills Other problems occur due to the stochastic nature of the wind The paper concentrates on the problems occurring in the eastern Danish power system up to year 2008, where three off-shore wind farms each of 150 MW will be connected to the system To integrate such a large amount of production from windmills creates a technical challenge, which affects the basic principles for both planning and operation of the system

Analysis of Wind Power Ancillary Services Characteristics with German 250-MW Wind Data

Abstract: With the increasing availability of wind power worldwide, power fluctuations have become a concern for some utilities. Under electric industry restructuring in the US, the impact of these fluctuations will be evaluated by examining provisions and costs of ancillary services for wind power. This paper analyzes wind power in the context of ancillary services, using data from a German 250 Megawatt Wind project.

Large-scale active-load modulation for angle stability improvement

Abstract: Analyses, operating experience and simulations of a large power system are used to demonstrate that active-load modulation can improve the system's dynamic performance to a large extent, with just a fraction of the base load available for control. At a time when the cost effectiveness of FACTS devices for damping interarea oscillations is constantly being questioned, it is natural to look to active-load modulation as a potential alternative method of insuring grid reliability. In developing the case, it was found that continuously modulating load stabilizers need to be fed with global signals for full efficiency. Although more difficult to design, implementation of a discontinuous control scheme shows good prospects, especially with regard to decentralization and robustness against communication delays.

Method of controlling load on power plant and load control system for carrying out the same

Abstract: The invention suppresses the production of thermal stress in power generating equipment and the unstable behavior of the power generating equipment due to the variation of system frequency and stabilizes the system frequency. A power plant load control system controls the operation of a power plant equipped with a gas turbine comprising a combustor ( 1 ) and a turbine ( 3 ), and a power generator ( 5 ) disposed coaxially with the turbine. The power plant load control system comprises a governor load control unit ( 100 ) for determining a governor instruction ( 103 d ) on the basis of the deviation of generated power ( 102 d ) from a power generation instruction ( 101 d ) given thereto by a central load dispatching station according to the variation of system frequency, and for determining a fuel supply rate instruction ( 107 d ) corresponding to a speed droop ratio (R) according to the deviation of shaft speed ( 104 d ) from a governor instruction ( 103 d ). The governor load control unit ( 100 ) has a fuel supply rate instruction limiter ( 107 ) for limiting the change rate of the fuel supply rate instruction ( 107 d ). The fuel supply rate instruction limiter ( 107 ) determines a limit to the change rate so that the production of thermal stress in the gas turbine and unstable combustion may be suppressed, and limits the variation of the fuel supply rate instruction ( 107 d ) to a range below the limit.

Expected benefits of adjustable speed pumped storage in the European network.

Abstract: In the context of a sustainable development the optimal use of the electrical energy will require advanced networks allowing interconnections on very long distances and addressing the storage challenge. These requirements are essentially due to the following reasons: - Electrical energy, contrary to most other kind of energies, must be simultaneously produced and consumed, because it is not possible to store directly large amounts of it. - Electrical energy is generated to a large extent by thermal power plants or by run-of-river stations operating as base load units at nearby constant power.

An on-line determination of the ready reserve power

Abstract: The paper presents usage of an artificial neural network (ANN) for the on-line determination of the ready reserve (RR) required for compensation of power deficit in power systems. The power deficit usually results after generator outage or failure of the other means of ensuring the operational reserve. RR consists of rapid start-up generating units such as gas turbines and hydro plants. Due to the stochastic nature of the power system operation, the amount of ready reserve is essential for balancing the power system operating states in perturbed conditions. For that purpose, an ANN using back-propagation learning rule could yield the amount of ready reserve. Prompt assessment of the appropriate amount of RR minimizes the potential reduction of quality of electrical energy delivered to customers and, consequently, maintains a high reliability of the power system as a whole.

A life cycle assessment scheme for environmental load estimation of power generation systems with NETS evaluation method

Abstract: This research is to analyze the environmental load on three types--natural, fossil-fuel, and nuclear power generation systems in lifecycle from the cradle to the grave. This study presents the numerical results on net energy, resources consumption and emissions of various electricity generation systems, using a whole-fuel-chain approach. For the assessment, the authors evaluated these systems using NETS (Numerical Environment Total Standard) evaluation method that is proposed here. This method describes impact on the environment in which the values change in them according to the maximum sufferable value. The NETS value is calculated from the total summation of respective environmental indices on whole processes in life cycle. As the result, a list of estimations using NETS values in power generation systems for input resources and output emissions is created as points of reference for further development and refinement to much more eco-power generation systems.

Models for probabilistic power transmission system reliability calculation

Abstract: In Denmark, many independent power producers such as windmills and small gas- or oil fuelled combined heat and power plants (below 50 MW) have been set up in the last few years. Further, the larger power plants in Denmark are combined power plants with heat production to district heating. Understanding of this complex utility system with regard to cost and reliability are to be examined by a probabilistic network planning program, which can take into account all these specialities for the Danish network and include probabilistic models for the load and for the transmission system as well. Such a program has been set up with stochastic models of the windmills, the loads, the small combined heat and power plants and the heat production from the larger power plants. The models are used on a realistic network grid, and Monte-Carlo simulations are used in the final simulation program.

Stability of a pump storage hydro-power station connected to a power system

Abstract: The operational flexibility of pumped storage hydropower stations means that they are often used for the control of power system frequency. When used in this role, the response of the power station is determined by the behaviour of its governor, the stiffness of the connected grid and the interaction between the governor and the grid. An investigation into the governor settings at Dinorwig power station in the UK has been undertaken in order to establish the optimum governor settings for different loading conditions, providing as close to an ideal response as possible without endangering the stability of system frequency control. The gain and phase margins of the open loop transfer function of the system were examined to determine the stability of the power system, and the effect of the droop settings and the grid size are included in the study. Information on stability of the power station is presented for a variety of operating and grid conditions.

Weather sensitive short-term load forecasting using artificial neural networks and time series

Abstract: In this paper, a novel weather sensitive (WS) load model using a back-propagation artificial neural network (ANN) is proposed to reflect the load's dependence on temperature, hours of a day, days of a week, and seasonal effects. The model inputs are temperature offsets from the winter and summer changeover temperatures, average weekly and daily temperatures to cater for seasonal effects, and radial basis functions (RBF) centered at peak sensitivity points of load versus temperature to indicate the hours of a day. The other load components, which are the base load (BL) and the residual load (RL) components, are modelled using time-series ANN models. A special load history set is put into focus and used for the base load forecast. It is derived using a third order difference scheme that reduces the base load sequence into a stationary white-noise-like process, thus allowing linear estimation to be used. This same load history has also proven to be very successful when applied to one step ANN load forecast models. It allows the forecast to be carried out based on load and temperature inputs only, with no need to indicate the hour or day-type of the forecast. This leads to a big reduction in the number of inputs required and allows for the use of linear activation functions, which results in a dramatic reduction in the learning time required to calculate the model's coefficients. An investigation of radial basis function (RBF) network models also shows the appropriateness of this load history set for such models, but reveals their weak responsiveness to temperature inputs. Results from the three models are then compared when they are used to forecast the hourly loads of a winter and spring week of a typical north-European utility.

Reliability-based impact analysis of independent power producers for power system operations under deregulation

Abstract: In this paper, the authors present an evaluation procedure of independent power producers' impact on reliability and associated costs of existing power systems under deregulation. Independent power producers (IPPs) with competitive electricity prices can contribute to the cost reduction of electricity supply under the open access power systems. However, there is a concern that the high standard of power system reliability may not be maintained because of possible failures of such new generators. IPPs' effects on supply reliability are closely related to generation and transmission operation of existing power systems. In the proposed approach, the reliability is measured by expected unserved power (EUP) and the additional cost of reliability maintenance is calculated by the cost of generation adjustment. The optimal redispatch problem is solved with the reliability index as a constraint. Also, a transmission system congestion is considered in the redispatch. Numerical simulations have been conducted on a model system with six nodes and seven branches.

Private power generation facility

Abstract: PROBLEM TO BE SOLVED: To provide a private power generation device suitable for following load power with respect to large load fluctuation, such as a general house and to provide the control method in a private power generation facility supplying power to houses and the respective partitions of an apartment house on a cogeneration facility provided with a power generation function. SOLUTION: A private power generation facility is provided with a power generation facility using an internal combustion engine, a power conversion device converting power generated in the power generation facility, and a storage facility accumulating power generated in the power generation facility. A controller for detecting the output of the power generation facility, the capacity and the load power of the condensing facility and controlling the output of the power generation facility following the fluctuation of load is installed.

Base-load solar thermal power using thermochemical energy storage

Abstract: Using a closed-loop thermochemical system based on the reversible ammonia reaction is one of the possible ways for building solar thermal power systems capable of providing electricity on a 24-hour basis without the need for any fossil fuel back-up. In a collaborative effort between industrial and academic partners from Australia, Switzerland, Germany and Malaysia, a study was undertaken to examine the techno-economic viability of this solar concept by formulating a preliminary design for a hypothetical 10 MW e demonstration system in Central Australia It was found that a carefully designed demonstration solar power plant, which dominantly uses proven and standard materials, components and technologies, is likely to cost of the order of AUD 157 million and operate with a net solar-to-electric conversion efficiency of 18% and a capacity factor of 80%. This will result in levelised electricity costs (LEC) of about AUD 0.24 per kWh e .

300 kW battery energy storage system using an IGBT converter

Abstract: Increasing automation in modern industry and deregulation have changed the requirements on power quality. Computer and process control equipment as well as drive converters are sensitive to deviations of the line voltage from the ideal sinusoidal. Voltage sags, harmonic distortion, flicker and interruption of power supply are the most common problems. In an increasing number of cases, where conventional equipment cannot solve these problems, PWM converter-based shunt- and series connected power conditioners named DSTATCOM (distribution static synchronous compensator) and DVR (dynamic voltage restorer) have been introduced. With energy storage added to the power conditioner even more flexibility in system operation and planning is provided for utilities and industry. This paper describes such a 300 kW power conditioner with a chemical battery and its benefits to an industrial plant. If, for example, load demand exceeds the power rating of the supplying transformer or the negotiated power with the utility only at certain times of day, the excessive active power demand can be provided by the power conditioner. In addition, the power conditioner can be used for reactive power compensation or other tasks, if it is not fully used for charging or discharging. The new technology can therefore be used to postpone or avoid major investments and to optimize energy consumption costs.

Method for controlling power source of hybrid-driven mobile

Abstract: PROBLEM TO BE SOLVED: To provide a method for controlling the power source of a hydrbid- driven mobile by which stable running of the mobile can be secured by coping with load fluctuation by efficiently properly using a fuel cell and a battery, based on their characteristics and the deterioration of the battery can be suppressed by eliminating the capacity insufficiency of the battery. SOLUTION: In a method for controlling the power source of a hybrid-drive mobile provided with a motor-driven power source 31 and a fuel cell 70 and a secondary battery 60 both of which are used as power sources for supplying electric power correspondingly to the load on the power source 31, the electric power corresponding to a substantially less fluctuating base load (b) at a prescribed level is supplied to a fluctuating load (a) from the fuel cell 70 and the electric power corresponding to a fluctuating load portion (c) is supplied from the secondary battery 60.

Optimal power flow formulation in market of retail wheeling

Abstract: Power system deregulation along with retail wheeling was proposed in legislation for the future power system operation. Retail wheeling implies customers have more choices. One important option is the power supplier providing cheaper power. In this paper, the authors introduce new concepts of generation sets and load sets to model the behavior of power supply and load distribution in the new retail wheeling market. Formation of the optimal power flow (OPF) problem, in which public interests are maximized, is demonstrated. The IEEE-14 bus system is used as an example.

Regulating total power of power generation system(s) with group of loads involves using load schema enabling more cost-effective utilization of energy tariffs with load time shifts

Abstract: The method involves determining the load profile of the power generation system, producing a load operation schema enabling more cost-effective utilization of energy tariffs by using potential time shifts of load power demands than for operation according to load profile, and operating the loads so that the system maintains the load schema.

Market monitoring and leader follower incentive control of ancillary services

Abstract: The problems of market monitoring and the control of ancillary services of a future energy system are presented. We envision that the future system operation of electric power systems will evolve into completely unbundled ancillary service markets that are governed by spot-price signals. The grid operators need to acquire ancillary services through competitive markets for control of the system operation. With the above vision of the future, this paper presents the control of ancillary services based on a frequency regulation/load-following control (LFC) market, a regulated load (RL) market and a base load (BL) market. In the LFC market, the units dispatched for generation must have specific response characteristics as determined by the nature of the system loads. These units are controlled by the grid operator. It is envisioned that LFC will be multi-time-scale and decentralized. In the RL market, the units dispatched for generation do not participate in LFC. These units are dispatched for a specific period of time for regulating the system load. The BL units are dispatched daily to satisfy the BL of the day on a weekly or monthly basis. The locational market power associated with generators participating in LFC and in RL is even move critical than that for generators participating in satisfying the BL since these units are required for frequency regulation, voltage support and relief of overload conditions. To create an efficient market for these services, we propose and formulate the use of incentive leader-follower strategies for the BL, RL and LFC markets.

Lastmanagement einer zukünftigen Energieversorgung : Integration regenerativer Energien in die Elektrizitätsversorgung

Abstract: A higher contribution of renewable power plants to electricity supply decreases the base load of conventional power plants and an excess of generation is possible. An optimized demand management can improve the integration of renewable power plants into the grid.

Maintaining Generation Adequacy in a Restructuring U.S. Electricity Industry

Abstract: Historically, decisions on the amounts, locations, types, and timing of investments in new generation have been made by vertically integrated utilities with approval from state public utility commissions. As the U.S. electricity industry is restructured, these decisions are being fragmented and dispersed among a variety of organizations. As generation is deregulated and becomes increasingly competitive, decisions on whether to build new generators and to retire, maintain, or repower existing units will increasingly be made by unregulated for-profit corporations. These decisions will be based largely on investor assessments of future profitability and only secondarily on regional reliability requirements. In addition, some customers will choose to face real-time (spot) prices and will respond to the occasionally very high prices by reducing electricity use at those times. Market-determined generation levels will, relative to centrally mandated reserve margins, lead to: (1) more volatile energy prices; (2) lower electricity costs and prices; and (3) a generation mix with more baseload, and less peaking, capacity. During the transition from a vertically integrated, regulated industry to a deintegrated, competitive industry, government regulators and system operators may continue to impose minimum-installed-capacity requirements on load-serving entities. As the industry gains experience with customer responses to real-time pricing and with operation of competitive intrahour energy markets, these requirements will likely disappear. We quantitatively analyzed these issues with the Oak Ridge Competitive Electricity Dispatch model (ORCED). Model results show that the optimal reserve margin depends on various factors, including fuel prices, initial mix of generation capacity, and customer response to electricity prices (load shapes and system load factor). Because the correct reserve margin depends on these generally unpredictable factors, mandated reserve margins might be too high, leading to higher electricity costs and prices. Absent mandated reserve margins, electricity prices and costs decline with increasing customer response to prices during high-demand periods. The issues discussed here are primarily transitional rather than enduring. However, the transition from a highly regulated, vertically integrated industry to one dominated by competition is likely to take another five to ten years.

Power Control for Wind Turbines in Weak Grids: Project summary

Abstract: In many parts of the world and certainly in Europe large areas exist where the wind resources are good or very good and the grid is relatively weak due to a small population. In these areas the capacity of the grid can very often be a limiting factor for the exploitation of the wind resource. There are two main problems concerned with wind power and weak grids. The first is the steady state voltage level. When the power consumption is low e.g. during the night the voltage of the grid can increase to levels above the limits if the wind power input is high. The other main problem is voltage fluctuations. Because the wind is fluctuating the output from the wind turbines is also fluctuating. This together with wind turbine cut-ins can result in voltage fluctuations that are above the flicker limit. Some or all of the these problems can be avoided if a so-called power control concept is applied together with the wind farm. The idea behind the power control concept is to eliminate the violations of the steady state voltage level by buffering the power from the wind turbines in periods where the voltage limits might be violated and then release it when the voltage level is lower and combine this ability with smoothing of the power output in order to remove power fluctuations that otherwise would create voltage fluctuations above the flicker limit. The project consists of three parts: investigation of the general applicability of the power control concept, design, implementation and testing of a battery based prototype and two case studies. In order to assess the general applicability of the concept a framework has been formulated in which the different options (power control concepts, grid reinforcement and dumping of surplus wind energy) can be compared. As part of this, models have been developed, that can assess the voltage fluctuations and the steady state voltage behaviour for the different options. The investigations have shown that the power control concept can compete with grid reinforcement and usually the dumping of wind energy will be the most expensive option (in the case where rather large amounts of wind energy are installed). The prototype of a socalled ‘add-on’ power controller has shown that it is possible to control the output from the combined system so that the fluctuations in power are much reduced and at the same time the reactive power is controlled to a desired value. The two case studies (Madeira, Portugal and Co. Donegal, Ireland) revealed that sometimes the least cost and most attractive option is change in the operating strategy of the power system. This allowed that further wind energy can be integrated at competitive cost in the Madeira power system. In Co. Donegal the options for pumped storage are good combined with good wind resources. Unfortunately the grid is weak. The least cost option for the feeder studied is either grid reinforcement or a power control system based on pumped storage if rather large amounts of wind energy are to be absorbed by the power system. The cost estimates for the two options are in the same range. The current report is a summary of the work done in the project 'Power Control for Wind Turbines in Weak Grids'. The project has been partly funded by EU under contract JOR3-CT95-0067. ISBN 87-550-2546-3 ISBN 87-550-2547-1(Internet) ISSN 0106-2840 Information Service Department, Riso, 1999 Riso-R-1117(EN) 3

Supercritical coal fired power plants : a technology being successfully deployed in developing countries

Abstract: This paper reviews the major technical and performance aspects of a coal fired plan using the supercritical technology. These include the turbine-generator set, the once-through boiler, and operational issues such as load change, fuel flexibility, and water. Reviewing the possibilities for the design and manufacture of components for supercritical-fired plants in developing countries, the paper notes that the differences between sub critical and supercritical power plants are limited to a relatively small number of components; primarily the feedwater pumps and the high pressure feedwater train equipment. All of the remaining components, common both types of plants, can be manufactured in developing countries. The paper concludes with a review of the Schwarze Pumpe - the world's largest supercritical lignite fired steam power plant.

A new algorithm for load shedding in an industrial cogeneration power plant

Abstract: This thesis presents a new algorithm for an industrial power plant with cogeneration in operation. The new algorithm was developed to satisfy industrial cogenerator's requirements in load shedding.

The real cost of air conditioning load

Abstract: The significance of the air conditioning load and its impact on the daily fuel cost of electric power networks have been pointed out. A model has been developed for assessing the increase in the daily fuel cost due to the A/C load, taking into account both the system load characteristics (peak load, load factor, generation cost) as well as the parameters of the added air conditioning load (A/C peak load, starting time and its duration). The model allows for the consideration of two different control procedures used for reducing the daily cost of the power network's fuel consumption: delaying the A/C load starting time; and the utility-controlled disconnection of the A/C load for several minutes per hour. The simultaneous application of both strategies can be also simulated and economically assessed.

Decarbonized fuel production facility - a technical strategy for coal in the next century

Abstract: The US electricity market is undergoing major changes. Deregulation, increased competition, and growing environmental concerns are major challenges facing the electric power industry. These challenges also have the potential to significantly inhibit the future use of coal to produce electricity. In this paper, the authors describe a technical strategy for the coal industry that can help assure coal's competitiveness during the next century as the industry responds to these major challenges. Recently, the US Department of Energy unveiled a new concept. ``Vision 21''--a futuristic way of combining high-efficiency power technologies with advanced coal processing technologies and environmental controls to create a near-zero discharge, multi-product energy complex. This paper presents one conceptualization of a Vision 21 Plant that focuses on production of hydrogen from coal. It will show how the concept can help assure that coal can remain competitive with natural gas as a fuel for baseload electricity generation for existing and new power plants. It can also provide a feedstock for chemical and liquid fuels production, even if emissions of carbon dioxide must be controlled. Analyses are presented that provide the basis for the projected economic and technical performance objectives.

Operational experience with a superconducting magnetic energy storage device at Owens Corning Vinyl Operations, Fair Bluff, North Carolina

Abstract: This paper presents the operational and power quality monitoring results for 21 months operating experience of a superconducting magnetic energy storage (SMES) device used to mitigate power quality disturbances at the Owens Coming Vinyl Operations in Fair Bluff, North Carolina, USA, a vinyl siding manufacturer. The SMES unit at Owens Coming provides sag and momentary interruption ride-through for the plant's extrusion lines. Prior to SMES installation, power disturbances caused frequent production interrupts, which resulted in extensive extrusion line cleanup and contributed to other maintenance problems. Two SMES units have provided 233 carry-overs as of March 2, 1999. The recorded power disturbance data corroborates previously published power quality data indicating that the overwhelming majority of voltage sag and interruption power quality disturbances were less than two seconds in duration.