Showing papers on "Base load power plant published in 2000"

Providing premium power through distributed resources

Abstract: The modern industrial facility depends on sensitive electronic equipment that can be shut down suddenly by severe power system disturbances. A large number of these disturbances on the power system are a result of line faults which can cause momentary voltage sags. This results in equipment malfunctioning and high restart cost. This papers describes the control of distributed resources as a solution to such problems. In particular the focus is on systems of distributed resources that can switch from grid connection to island operation without causing problems for critical loads.

Load power reduction control and supply system

Abstract: The invention is a load voltage and power control and supply system for the supply of power to a load for which, over particular periods of time, usually on a daily basis, it is desired to reduce power. The invention has particular application to street lighting systems in which, for a period of several hours during the night (when traffic is minimal and many people are asleep), the luminaires of the lighting system can operate at reduced power. The power control system is able to act as a voltage stabilizer as well as a controlled power reduction system. The power control system may operate the bank of spaced luminaires from a single control location. Moderately reduced power (say a 30% reduction in power) supplied to luminaires does not noticeably diminish the adequacy of the illumination provided. Further, the power control system reduces power in stepwise decrements each of which reduces power by a small amount insufficient to diminish noticeably the ambient illumination.

Load management techniques

Abstract: Electric power has shaped and contributed to the progress and advances of humankind over the past century. Power should be available to the customer upon demand. The power companies strive to keep the reserve capacity to meet the sudden demand to a minimum. Load management techniques help the power company to reshape the electric utility load curve and to reduce the peak demand. The United States Government has filed lawsuits against 32 electrical utility plants charging the release of massive amounts of air pollutants throughout the Midwest and East coast. Electrical utilities are responsible for 65% of sulphuric dioxide emissions in the United States. If the customers demand more power, the power companies would supply power by building more generation facilities. This concept of supply-side management has been very popular in the seventies of the twentieth century. The demand-side management techniques influence the customers to help to reshape the load demand curves. This article analyzes the load management techniques in great detail. The power company must devise incentives to help customers to modify the load-curves. The customers must change their lifestyles to help to implement the load management techniques. Load management techniques make electricity do more by using it better. The important point is that less energy is wasted. Load management techniques could force the utilities to become globally competitive and control the demand and energy consumption.

Load following functions using distributed energy resources

Abstract: Technology improvements in fuel cells, microturbines and energy storage devices have provided the opportunity for dispersed energy resources at the distribution level. At the same time, deregulation has begun to allow for the provision of various ancillary services, such as, load following. This paper investigates some possible approaches to load following, at the distribution level. An algorithm is proposed for the fast three phase load flow calculations needed to simulate the slow dynamics of load following. We simulate a typical distribution system where several distributed energy resources have been added. Using simplified dynamics for the sources and loads, strategies to provide load following without increased unbalance are suggested. We identify modeling improvements that are needed to fully investigate these algorithms.

Dispersed energy community system and control method

Abstract: PROBLEM TO BE SOLVED: To provide a system which can use energy in communities effectively and maintain a stabler system voltage. SOLUTION: A center 11 receives data of quantities of power generated by fuel cells 5, energy stored by batteries 6 and power consumption by loads 7 from houses 1 and controllers in other dispersed power systems through a communication line 10 and stores to a database. The center instructs each dispersed power system in values of generated, supplying and supplied power based on the database. The center complements and controls supply and demand of power between a plurality of dispersed power systems with different characteristics of daily load for demand of power. A fuel cell 14 and a battery 15 in the center 11 can store and supply power.

Reliability model of wind power plants and its application

Abstract: In this paper, a reliability model of wind power plants is presented. The wind distribution and correlation between wind power plants, power curve and forced outage rate (FOR) of wind turbine generators, wake effects and temperature etc. are included in the model. The utilization of this model in probabilistic production simulation (PPS) and probabilistic load flow (PLF) are also discussed. Using PPS, the capacity credit and avoided cost of wind power plants can be studied. By the use of PLF, the distribution of power flow and node voltage can be calculated, therefore the penetration level of wind power can be determined. These are very important for grid connected wind power planning.

Power source control method for an electric vehicle

Abstract: An electric vehicle comprises a first power source and a second power source. The first power source can be used to supply a substantially constant base power level and the second power source can be used to supply a variable power level such that a variable load demand can be filled by combining the base power level and the variable power level. The first source can be used to supply power to the second source when the second source is operating at a decreased charge or power level. The base power level can be varied based upon the remaining charge or power level contained within the second source. A number of control methods for operating the power supply of the electric vehicle are disclosed.

Method and apparatus for powering up an electronic system after AC power has been removed

Abstract: In an electronic system with multiple power supplies, a method and apparatus dynamically determines the number of power supplies required to power up the system without overloading any supply. The individual power supplies do not turn on until the determined number of power supplies have received AC power and become operational before attempting a complete system power on. The amount of required power is determined before power up based on the actual power load present. The actual load is determined by sensing load indicators in each load device and computing the total power load. The amount of power from supplies which have received AC power is determined by detecting when AC power has been applied to each power supply and computing the total amount of power available. System power up is delayed when the number of power supplies which have received AC power is insufficient to power the system without an overload situation occurring.

Variable base load energy management system and method

Abstract: The present invention is a system and method for variable base load demand-side energy management. The system of the present invention includes a power reduction device receiving electrical power from an electrical power source and outputting electrical power to a load. The system of the present invention can control the power delivered to one or more devices in a single facility or to multiple facilities. The system of the present invention can control the power delivered to one or more devices located in one or more facilities by sending control signals over various kinds of networks using various communication methods simultaneously, such as a modem, a LAN, or a WAN such as the Internet.

Control system for electric power demand and supply

Abstract: PROBLEM TO BE SOLVED: To supply electric power to plural consumers within a prescribed region (a community), some of which are equipped with distributed power supply systems, to demand or supply among the above consumers at a low cost and to make the power system stabilized by these. SOLUTION: Electrical energy is input to the distributed systems 4, which is installed in one of the consumers of plural 3a to 3n power provided inside the community, into the energy storage facility 6h or is output and is stored in the facility 6h. The sum of the purchased power and the generated power which are distributed to each consumer in the community as in response to respective demands, and the former power is purchased through the accounting service device and the latter is generated by distributed systems 4 inside the community C as a whole. If there is a difference between the sum of demand and the sum of supply, the power demand and supply control device 6d controls the operation of the systems 4, so as to regulate the power demand and supply to cancel the difference via the distributed power control device.

Power storage device and control method of distributed power supply system equipped therewith

Abstract: PROBLEM TO BE SOLVED: To surely restrain fluctuations in output to a power system due to a distributed power supply, such as wind power generation and solar power generation by preventing a power storage part from having storage shortage or being kept in a fully charged condition. SOLUTION: This distributed power supply system 10 is provided with a power storage device 1 consisting of the distributed power supply 9, the power storage part 2, a power-regulating part 3, and a control part 4 and is connected to the power system 12. The control part 4 consists of an output detecting part 5, a storage detecting part 6, a target value setting part 7, and a regulating output control part 8. It detects an output P of the distributed power supply 9 and the storage amount of the power storage part 2, presets an output target value P0 for restraining fluctuations in the output to the power system 12 by the distributed power supply 9 according to the storage amount, and controls the power regulating part 3 so that the output to the power system 12 reaches the output target value P0.

Cold load pick-up of residential load

Abstract: Field studies have been performed in residential areas to determine the load restoration process after a disturbance. Similar measurements were also performed for individual houses with different heating supplies. Load aggregation for the different houses during the same outdoor conditions have been made for various durations of the outages, and a load model is presented. The cold load pick-up from individual houses is compared with field measurements from substations and with load models. Load curtailment schemes are analysed based on the collected data.

Modelling the Impact of Wind Power Fluctuations on the Load following Capability of an Isolated Thermal Power System

Abstract: W ind power is a clean and commercially competitive renewable energy technology that affords many utilities the opportunity to diversify and reduce their dependence on fossil fuels. However, the wind is also an intermittent energy source. Hence, many small and isolated utilities are concerned that, as the number and capacity of wind power plants increases, the resulting fluctuations in wind power output will impose excessive load following duty on their conventional units,leading to grid frequency control problems. This paper investigates the potential impact of wind energy development on the load following capability of a representative medium-sized, (2000 MW) thermal power system. Recorded system demand and wind power production data from the Northern Ireland system are statistically analysed, and the impact of expanded wind farm operation on net wind power and system demand fluctuations modelled and predicted for various time-scales of interest. The results demonstrate that the magnitudes of power outp...

Electrical peak load distributor

Abstract: The invention relates to a method and apparatus for peak laod distribution. A peak load distributor (10) reduces the demand on power distribution system by controlling the power available to loads. The apparatus takes an AC current input and a micro-controller executes control algorithms to open and close power outputs to deferrable loads. The outputs are generally put in series with the power applied to a load to disable the load or to lower peak demand.

A study of transmission planning under a deregulated environment in power system

Abstract: Under a deregulated environment, power system operators such as utilities have to expand and reinforce the transmission network so that all participants can utilize the network equally and fairly. However, it is difficult for the power system operators to forecast how often the network will be utilized or which bus the users will connect to. Therefore, more uncertain factors exist in the transmission planning problem under a deregulated environment. This paper presents a method for evaluating the maximum power which can be injected to a bus and identifying some transmission lines which result in the bottleneck under the uncertain conditions. This paper also investigates a probabilistic load flow to consider the statistic characteristics of load change and line fault occurrence.

Tidal Stream Renewable Offshore Power Generation (TS-Ropg)

Abstract: Publisher Summary The Engineering Business is developing a number of practical tidal stream power generation schemes. They are all based on rotating hydrofoils up and down to generate oscillatory motion from flowing water. Two schemes are described in the chapter: the Active Water Column Generator (AWGC) and the Stingray tidal stream generator. The AWCG development has been partly funded by a DTI Smart Award. With a growing market for renewable energy several technologies are becoming established. EB believes that tidal stream energy can compete with offshore wind developments. It depends on the available energy at the proposed site and the economics of installing the additional generating capacity. The predictable nature of tidal stream energy can complement the variability of wind power by providing a regular base load supply.

Electricity rate control device and recording media therefor

Abstract: PROBLEM TO BE SOLVED: To provide an electricity rate control device, capable of managing electricity rate by setting target values for electricity rate, service electrical energy in full electric power load, or CO2 within facilities for such a prescribed period as monthly or yearly unit, thereby controlling service electrical energy and maximum electric power in an electric power load based on the target values SOLUTION: Estrangement rate is calculated by a load pattern identifying part 3, and adjusted electrical power and a target coefficient are calculated in an adjusted electric power computing part 5 and a target coefficient computing part 7, based on sample data stored in a sample data storing part 2 on service electrical energy in an electric power load A demand time limit target value computing part 8 calculates the target value of electrical energy used in an electric power load for each demand time limit based on the estrangement rate, the adjusted electrical power, and the target coefficient Thus, the amount of electric power used in electricity load can be controlled by a demand control part 9 and a load control part 10 based on the target value

An integrated tool for analysis of power system constraints in the Spanish electricity market

Abstract: The role of the system operator in the Spanish electricity market, as it started on January 1/sup st/ 1998, is to determine the technical feasibility of the generation dispatch provided by the market operator. The security criteria of the Spanish power system require that branch power flows and bus voltages are within their limits, not only in normal operating conditions but also when any credible contingency occurs. This paper presents an integrated tool for analysis of power system constraints in the Spanish electricity market. The components of this tool are: a power system scenarios builder; contingency analysis routines; and preventive dispatch algorithms (active and reactive power). The tool addresses separately the overloaded branches and the bus voltage violations. The performance of the tool is illustrated using an actual scenario of the Spanish power system.

Power source control method for a hybrid-driven mobile body

Abstract: A power source control method for a hybrid-driven mobile body comprising a motor type power system for travelling, and a fuel cell and a secondary battery as power sources for supplying electric power in response to load of said power system. To a varying load, electric power corresponding to a base load portion at a given level and with a substantially small variation is supplied from the fuel cell and electric power corresponding to a varying load portion is supplied from the secondary battery.

Fuzzy scheduling control of a power plant

Abstract: Current control strategies for fossil fuel power units are multiloop schemes based on conventional PID control algorithms, that have demonstrated their effectiveness to regulate power output under random load disturbances. Normally, the parameters of the controller are tuned at a predefined operating point (i.e., base load), and left fixed thereafter. However, wide-range load-tracking operation challenges this approach. The performance of the unit may decrease due to the nonlinear dynamics of the process, that change with the operating point. Gain scheduling and multimode control have been pointed out as two viable control alternatives to deal with this problem in industrial processes. This paper introduces a fuzzy PID controller that merges both techniques in a single mechanism that preserves their advantages. The amalgamation is carried out by a multi-input-single-output Sugeno-type fuzzy inference system. This controller is used to extend the application range of the control system in a power plant without changing the essential philosophy of the already existing control structure, achieving smooth wide-range load tracking operation.

Modeling and control of electric power systems and markets

Abstract: IEEE Control Systems Magazine August 2000 Over the last century, various aspects of power systems have presented numerous theoretical and practical challenges to the control community, ranging from the control of electric motors to the operation of the electric power grid. Challenges persist and include modeling, prediction, simulation, cause-and-effect relationships, analysis, optimization, and control of a large-scale multilayered system comprising a heterogeneous mixture of dynamic, interactive, and often nonlinear entities, unscheduled discontinuities, and numerous other significant effects. The increasing complexity of electric power networks, their interconnections to other infrastructures, their vulnerabilities to cascading failures, and their interactive and large-scale nature, coupled with advances in modeling, computational methods, software technologies, simulations, control of networks, and economic aspects, have stimulated increased interest on the part of the control community. From a broader historical perspective, reliable energy, transportation, and communication networks constitute the foundation of all prospering societies. For example, the U.S. electric power grid has evolved over the last hundred years to the point where it now underlies every aspect of our economy and society; it has been hailed by the National Academy of Engi-

PV battery wind-turbine public-grid hybrid power supply for telecom.-equipment, system management and control

Abstract: As a result of the increasing acceptance of renewable energy conversion technology, hybrid power systems now represent the preferred choice for electrical power at many remote sites. These systems include the following power elements; photovoltaic panels, storage batteries, wind turbines, public grid and system controls. The system architecture combines the power systems on the DC bus where the load distribution and battery storage is also located. The system controller provides supervisory control of all power system elements as well as protection. The operation of a stand-alone photovoltaic system depends not only on the quality of the individual system components but also on their interaction in the total system. The demands on the operation control, which co-ordinates the interactions, increase with the system complexity. The significance of the operation control is due to its influence on the reliability of the energy supply and on the component lifetimes. This paper introduces the design and implementation of a hybrid power system. A new technique is used to control the battery charging current. A developed control algorithm is created to give 100% priority to the load tasks as well as to manage and protect the system components.

Distributed power supply system and its control method

Abstract: PROBLEM TO BE SOLVED: To curtail power cost without increasing the capacities of power generating equipment and storage, etc. SOLUTION: A controller 5 causes a power converter 4 to control the quantity of charging and discharging of a capacitor 3 with respect to rapid power load variation, and gives a command to the power converter 4 and causes it to control power to be consumed in a specific load 8 for the purpose of controlling the peak of short-time load power consumption. The difference between power generated by a fuel cell 1 and power consumed by the load 8 is compensated by controlling charging and discharging of a battery 2. A command is given so that a charged quantity of the battery 2 may be in a specified range, and generated energy of the fuel cell 1 is controlled. When the power of the fuel cell 1 and the battery 2 is short, power is received from a power system 7.

Power saving controller and power saving method for device power source and recording medium

Abstract: PROBLEM TO BE SOLVED: To provide a power saving controller and a power saving method for a device power source on which a plurality of power sources are mounted and a recording medium. SOLUTION: The load state of a device is monitored, and whether or not the power consumption of the load is decreased is determined based on beforehand set determination information, and when the power consumption is decreased, only the selected power source is allowed to operate based on beforehand set power saving mode information, and power supply matched with the power consumption is performed.

Operation and control of island systems-the Crete case

Abstract: In this paper, an advanced control system for the optimal operation and management of isolated power systems with increased renewable power integration is presented. The control system minimises the production costs through on-line optimal scheduling of the power units, taking into account short-term forecasts of the load and the renewable resources. The power system security is supervised via on-line security assessment modules, which emulate the power system frequency changes caused by pre-selected disturbances. For each of the above functions, a number of techniques have been applied, both conventional and AI based. The system has been installed in the dispatch center of Crete since June 1999, and is under evaluation.

Control equipment of integrated coal gasification combined cycle power generation plant

Abstract: PROBLEM TO BE SOLVED: To provide control equipment of an integrated coal gasification combined cycle power generation plant capable of improving following-up of an amount of gas emission for a change in load demand when controlling the integrated coal gasification combined cycle power generating plant with a gasification furnace lead method. SOLUTION: In the load control equipment a load control signal is produced based on a deviation between a generator output and a load demand of the integrated coal gasification combined cycle power generation plant and preliminary control demand indicated in a function value of the load demand. The load control signal added by the preliminary control demand is output to a gasification furnace control device. Since a fuel is fastened to induce into the gasification furnace by the preliminary demand, the gas pressure in an upper stream from a pressure control point is fastened to increase, therefore a load controllability improves. COPYRIGHT: (C)2002,JPO

Surplus power storing supplying apparatus

Abstract: PROBLEM TO BE SOLVED: To use mid-night surplus power, etc., generated in a nuclear power station without exerting a bad influence on an environment. SOLUTION: Water is electrolyzed by the surplus power, and power is generated by fuel cells using obtained hydrogen in a time zone when power demand is great. On this occasion, generation of the surplus power is sensed by time and by a report from a power company. Hot water is made by heat removed from the fuel cells, and is supplied to various parts. Besides, the obtained hydrogen is supplied to a fuel cell car. Ordinary power is obtained by using the surplus power.

Economies of scale and optimal selection of hydroelectric projects

Abstract: The authors define a purely hydroelectric power system as a power system consisting almost entirely of hydroelectric generating stations, where thermal backup stations are used only intermittently in dry periods. The expansion process for such a system consists of selecting from a set of available projects with certain investment cost and generating capacity characteristics. One of these characteristics is a measure of the economies of scale (EOS). In this paper, the EOS for hydroelectric projects are investigated by using available cost and capacity data from the Icelandic power system. Furthermore the tradeoff between large and small projects is investigated by weighting the lost sales during the period of excess capacity against the benefit of using larger projects due to the EOS. The optimum is shown graphically and depends on the demand growth and interest rate. The authors investigate a hypothetical example where a series of generating facilities can be replicated at will to satisfy a linear general demand. These results are then expanded by assuming a stepwise demand associated with each project to satisfy bulk energy demand such as that of an energy intensive industry. The results are illustrated graphically in a case study using data from the "purely hydroelectric" Icelandic power system.

Load factor of hydropower plants and its importance in planning and design

Abstract: In planning and design of new hydropower plants, the expected annual energy production is an important economical factor. The annual energy production of hydropower plants varies with availability of water and fluctuations in demand for electric power. Demand fluctuates between day and night, summer and winter and weekdays and holidays, sometimes in a deterministic manner, but there is considerable stochastic fluctuation too. Nevertheless, the statistical distribution of the instantaneous power load on the plant may be known, this is the power load duration curve. The water demand of the hydropower station does not have the same duration curve as the power demand due to the nonlinear effect of the energy losses in the water conduits. The duration curve for the water flow is derived from the duration curve of the demand. The load factor for the flow is calculated for the case when the duration curve of the market is according to Junges duration curve. Rules given on the estimation of available spinning reserve and the corrections that have to be made of the load factor if some peak power is produced by a thermal station the size of the hydropower station diminished accordingly. The effect of the difference of duration curves for power and water demand is demonstrated in a case study.