Power Saving MAC Protocols for WSNs and Optimization of S-MAC Protocol
Directory of Open Access Journals (Sweden)
Simarpreet Kaur
2012-11-01
Full Text Available Low power MAC protocols have received a lot of consideration in the last few years because of their influence on the lifetime of wireless sensor networks. Since, sensors typically operate on batteries, replacement of which is often difficult. A lot of work has been done to minimize the energy expenditure and prolong the sensor lifetime through energy efficient designs, across layers. Meanwhile, the sensor network should be able to maintain a certain throughput in order to fulfill the QoS requirements of the end user, and to ensure the constancy of the network. This paper introduces different types of MAC protocols used for WSNs and proposes S‐MAC, a Medium‐Access Control protocol designed for Wireless Sensor Networks. S‐MAC uses a few innovative techniques to reduce energy consumption and support selfconfiguration. A new protocol is suggested to improve the energy efficiency, latency and throughput of existing MAC protocol for WSNs. A modification of the protocol is then proposed to eliminate the need for some nodes to stay awake longer than the other nodes which improves the energy efficiency, latency and throughput and hence increases the life span of a wireless sensor network.
Connecting possibilistic prudence and optimal saving
Directory of Open Access Journals (Sweden)
Ana María Lucia Casademunt
2013-12-01
Full Text Available In this paper we study the optimal saving problem in the framework of possibility theory. The notion of possibilistic precautionary saving is introduced as a measure of the way the presence of possibilistic risk (represented by a fuzzy number influences a consumer in establishing the level of optimal saving. The notion of prudence of an agent in the face of possibilistic risk is defined and the equivalence between the prudence condition and a positive possibilistic precautionary saving is proved. Some relations between possibilistic risk aversion, prudence and possibilistic precautionary saving were established.
ONU Power Saving Scheme for EPON System
Mukai, Hiroaki; Tano, Fumihiko; Tanaka, Masaki; Kozaki, Seiji; Yamanaka, Hideaki
PON (Passive Optical Network) achieves FTTH (Fiber To The Home) economically, by sharing an optical fiber among plural subscribers. Recently, global climate change has been recognized as a serious near term problem. Power saving techniques for electronic devices are important. In PON system, the ONU (Optical Network Unit) power saving scheme has been studied and defined in XG-PON. In this paper, we propose an ONU power saving scheme for EPON. Then, we present an analysis of the power reduction effect and the data transmission delay caused by the ONU power saving scheme. According to the analysis, we propose an efficient provisioning method for the ONU power saving scheme which is applicable to both of XG-PON and EPON.
International Nuclear Information System (INIS)
Brightsen, R.A.
1979-01-01
In the opinion of many citizens, including the majority of those who oppose it, nuclear power will never recover from the 1979 accident at Three Mile Island. But some of nuclear power's supporters hope that the accident will shatter past smugness and spur constructive self-criticism on the part of the companies that build reactors, the utilities that buy them, and the Federal regulators who oversee their operation--and that it will usher in an era of truly safe atomic electricity. The article reviews deficiencies of the existing nuclear regulation - industry framework, and what must be done
Security constrained optimal power flow by modern optimization tools
African Journals Online (AJOL)
Security constrained optimal power flow by modern optimization tools. ... International Journal of Engineering, Science and Technology ... If you would like more information about how to print, save, and work with PDFs, Highwire Press ...
Energy saving and consumption reducing evaluation of thermal power plant
Tan, Xiu; Han, Miaomiao
2018-03-01
At present, energy saving and consumption reduction require energy saving and consumption reduction measures for thermal power plant, establishing an evaluation system for energy conservation and consumption reduction is instructive for the whole energy saving work of thermal power plant. By analysing the existing evaluation system of energy conservation and consumption reduction, this paper points out that in addition to the technical indicators of power plant, market activities should also be introduced in the evaluation of energy saving and consumption reduction in power plant. Ttherefore, a new evaluation index of energy saving and consumption reduction is set up and the example power plant is calculated in this paper. Rresults show that after introducing the new evaluation index of energy saving and consumption reduction, the energy saving effect of the power plant can be judged more comprehensively, so as to better guide the work of energy saving and consumption reduction in power plant.
Electric power production contra electricity savings
International Nuclear Information System (INIS)
Schleisner, L.; Grohnheit, P.E.; Soerensen, H.
1991-01-01
The expansion of electricity-producing plants has, in Denmark until now, taken place in accordance with the demand for electricity. Recently, it has been suggested that the cost of the further development of such systems is greater than the cost of instigating and carrying out energy conservation efforts. The aim of the project was to evaluate the consequences for power producing plants of a reduction of the electricity consumption of end-users. A method for the analysis of the costs involved in the system and operation of power plants contra the costs that are involved in saving electricity is presented. In developing a model of this kind, consideration is given to the interplay of the individual saving project and the existing or future electricity supply. Thus it can be evaluated to what extent it would be advisable to substitute investments in the development of the capacity of the power plants with investments in the reduction of electricity consumption by the end users. This model is described in considerable detail. It will be tested in representative situations and locations throughout the Nordic countries. (AB) 17 refs
Long-run savings and investment strategy optimization.
Gerrard, Russell; Guillén, Montserrat; Nielsen, Jens Perch; Pérez-Marín, Ana M
2014-01-01
We focus on automatic strategies to optimize life cycle savings and investment. Classical optimal savings theory establishes that, given the level of risk aversion, a saver would keep the same relative amount invested in risky assets at any given time. We show that, when optimizing lifecycle investment, performance and risk assessment have to take into account the investor's risk aversion and the maximum amount the investor could lose, simultaneously. When risk aversion and maximum possible loss are considered jointly, an optimal savings strategy is obtained, which follows from constant rather than relative absolute risk aversion. This result is fundamental to prove that if risk aversion and the maximum possible loss are both high, then holding a constant amount invested in the risky asset is optimal for a standard lifetime saving/pension process and outperforms some other simple strategies. Performance comparisons are based on downside risk-adjusted equivalence that is used in our illustration.
Long-Run Savings and Investment Strategy Optimization
Directory of Open Access Journals (Sweden)
Russell Gerrard
2014-01-01
Full Text Available We focus on automatic strategies to optimize life cycle savings and investment. Classical optimal savings theory establishes that, given the level of risk aversion, a saver would keep the same relative amount invested in risky assets at any given time. We show that, when optimizing lifecycle investment, performance and risk assessment have to take into account the investor’s risk aversion and the maximum amount the investor could lose, simultaneously. When risk aversion and maximum possible loss are considered jointly, an optimal savings strategy is obtained, which follows from constant rather than relative absolute risk aversion. This result is fundamental to prove that if risk aversion and the maximum possible loss are both high, then holding a constant amount invested in the risky asset is optimal for a standard lifetime saving/pension process and outperforms some other simple strategies. Performance comparisons are based on downside risk-adjusted equivalence that is used in our illustration.
Energy Technology Data Exchange (ETDEWEB)
Costa, Geraldo R.M. da [Sao Paulo Univ., Sao Carlos, SP (Brazil). Escola de Engenharia
1994-12-31
This paper discusses, partially, the advantages and the disadvantages of the optimal power flow. It shows some of the difficulties of implementation and proposes solutions. An analysis is made comparing the power flow, BIGPOWER/CESP, and the optimal power flow, FPO/SEL, developed by the author, when applied to the CEPEL-ELETRONORTE and CESP systems. (author) 8 refs., 5 tabs.
Power saving regulated light emitting diode circuit
International Nuclear Information System (INIS)
Haville, G. D.
1985-01-01
A power saving regulated light source circuit, comprising a light emitting diode (LED), a direct current source and a switching transistor connected in series with the LED, a control voltage producing resistor connected in series with the LED to produce a control voltage corresponding to the current through the LED, a storage capacitor connected in parallel with the series combination of the LED and the resistor, a comparator having its output connected to the input of the transistor, the comparator having a reference input and a control input, a stabilized biasing source for supplying a stabilized reference voltage to the reference input, the control input of the comparator being connected to the control voltage producing resistor, the comparator having a high output state when the reference voltage exceeds the control voltage while having a low output state when the control voltage exceeds the reference voltage, the transistor being conductive in response to the high state while being nonconductive in response to the low state, the transistor when conductive being effective to charge the capacitor and to increase the control voltage, whereby the comparator is cycled between the high and low output states while the transistor is cycled between conductive and nonconductive states
Strategies for Power/Energy Saving in Distribution Networks
Directory of Open Access Journals (Sweden)
GRIGORAS, G.
2010-05-01
Full Text Available The power/energy losses reduction in distribution systems is an important issue during planning and operation, with important technical and economical implications. Thus, the energy losses minimization implies not only the technical improvement of the network, through its renewal with the introduction of the technological innovations in the equipment and circuit components as well as the optimal planning of the design and development of the network, but also requires the use of the methods and software tools to facilitate the operation process. The paper presents a strategy for power/energy saving which replacement of the 6 kV voltage level with 20 kV voltage level in correlation with the extent of using efficient transformers. In this line, different urban distribution networks were analyzed using fuzzy techniques.
Saving assessment using the PERS in solar power towers
International Nuclear Information System (INIS)
Rodriguez-Sanchez, M.R.; Sanchez-Gonzalez, A.; Marugan-Cruz, C.; Santana, D.
2014-01-01
Highlights: • The lamination of the solar salt is avoided using the PERS and the main energy sink. • The PERS using salt pump as turbine saves 30–50% of the parasitic power. • The most appropriate configuration is a similar turbine three times one salt pump. • The payback period is around two years, and the economical savings from 1 to 4 M$. - Abstract: The improvement of the solar power tower using solar salt is one of the main goals of researchers. Any method or invention to improve the efficiency of this technology contributes to promote the renewable energies. The use of a Potential Energy Recovery System (PERS) in two different solar power tower plants of 20 and 100 MW has been analysed. The PERS is formed, at least, by one turbine, located at the hot salt pipe coming from the receiver. The turbine is engaged to the shaft of the feed pump, which raises the heat transfer fluid from the cold tank to the receiver. It reduces the parasitic power consumption of the plant, and increases its global efficiency. Different PERS configurations have been modelled. Based on an energetic and economic analysis, the optimal configuration is a geometrical similar turbine of three times the volume flow rate of one feed pump. The PERS has been proven to be a cost reductive and clean tool. For a 100 MW power plant of 30-year lifetime the investment cost is 1.26 M$ and the annual cash flow is 0.89 M$, while for a plant of 20 MW these values are 0.26 M$ and 0.19 M$, respectively
Energy Technology Data Exchange (ETDEWEB)
Dall' Anese, Emiliano; Simonetto, Andrea
2018-03-01
This paper considers distribution networks featuring inverter-interfaced distributed energy resources, and develops distributed feedback controllers that continuously drive the inverter output powers to solutions of AC optimal power flow (OPF) problems. Particularly, the controllers update the power setpoints based on voltage measurements as well as given (time-varying) OPF targets, and entail elementary operations implementable onto low-cost microcontrollers that accompany power-electronics interfaces of gateways and inverters. The design of the control framework is based on suitable linear approximations of the AC power-flow equations as well as Lagrangian regularization methods. Convergence and OPF-target tracking capabilities of the controllers are analytically established. Overall, the proposed method allows to bypass traditional hierarchical setups where feedback control and optimization operate at distinct time scales, and to enable real-time optimization of distribution systems.
Money in the bank : Feeling powerful increases saving
Garbinsky, E.; Klesse, A.K.; Aaker, J.
2014-01-01
Across five studies, this research reveals that feeling powerful increases saving. This effect is driven by the desire to maintain one’s current state. When the purpose of saving is no longer to accumulate money but to spend it on a status-related product, the basic effect is reversed, and those who
Energy Technology Data Exchange (ETDEWEB)
Becker-Ullmann, Siegfried; Selig, Ruediger [Siemens AG (Germany); Gaerisch, Stephan
2008-09-15
In the year 1989, Hela Gewuerzwerk Hermann Laue GmbH and Co. KG (Ahrensburg, Federal republic of Germany) adopted the former BAT tobacco goods factory Ahrensburg inclusive large parts of the infrastructure of the building, under it the supply of steam and warmth. Due to the constantly rising energy prices, Hela Gewuerzwerk Hermann Laue GmbH and Co. KG decided in the year 2006 to renew the entire supply of gas, warmth and coldness. On basis of a detailed analysis of the energetic requirement of all production departments and energy sectors, a concept was developed which is based on three factors: (a) Uncoupling of production of steam, warmth and coldness; (b) Decentralization: Steam, warmth and coldness are produced according to the user's demand; (c) Scaling: At least, for the generation of steam, warmth and coldness there are two identically constructed systems which are redundantly switched. By means of this concept, in the year 2007, approximately 8 millions kWh gas, 600,000 kWh electricity and 2,000 tons of carbon dioxide were saved.
Bruner, Alan Roy
1987-01-01
Reverse-flow HEXFET(R) minimizes voltage drop and power dissipation. HEXFET(R) scheme reduces voltage drop by approximately 80 percent. Design for power tap for random-access memory (RAM) has potential application in digital systems.
International Nuclear Information System (INIS)
Bogdan, Zeljko; Cehil, Mislav
2007-01-01
Long-term gas purchase contracts usually determine delivery and payment for gas on the regular hourly basis, independently of demand side consumption. In order to use fuel gas in an economically viable way, optimization of gas distribution for covering consumption must be introduced. In this paper, a mathematical model of the electric utility system which is used for optimization of gas distribution over electric generators is presented. The utility system comprises installed capacity of 1500 MW of thermal power plants, 400 MW of combined heat and power plants, 330 MW of a nuclear power plant and 1600 MW of hydro power plants. Based on known demand curve the optimization model selects plants according to the prescribed criteria. Firstly it engages run-of-river hydro plants, then the public cogeneration plants, the nuclear plant and thermal power plants. Storage hydro plants are used for covering peak load consumption. In case of shortage of installed capacity, the cross-border purchase is allowed. Usage of dual fuel equipment (gas-oil), which is available in some thermal plants, is also controlled by the optimization procedure. It is shown that by using such a model it is possible to properly plan the amount of fuel gas which will be contracted. The contracted amount can easily be distributed over generators efficiently and without losses (no breaks in delivery). The model helps in optimizing of fuel gas-oil ratio for plants with combined burners and enables planning of power plants overhauls over a year in a viable and efficient way. (author)
Can global warming save nuclear power?
International Nuclear Information System (INIS)
Pearce, D.
1994-01-01
Nuclear powered electricity generation in the United Kingdom has an uncertain future. The relative costs of generating electricity by nuclear fission compared to other means and the need for a desirable mixture or ''portfolio'' of energy sources in the electricity industry are identified as the key to this uncertainty. The author argues that Government commitments to reducing Carbon Monoxide (CO) emissions, and hence global warming, may strengthen arguments in favour of a firm commitment to nuclear power, as even modern fossil-fuelled power plants emit nearly 90 times as much CO as nuclear plants. (UK)
Optimal savings management for individuals with defined contribution pension plans
DEFF Research Database (Denmark)
Konicz, Agnieszka Karolina; Mulvey, John M.
2015-01-01
(or time left to retirement), nor should they solely depend on the risk preferences, but should also capture: (1) economical characteristics—such as current value on the pension savings account, expected pension contributions (mandatory and voluntary), and expected income after retirement (e...... characterizing the individual. The problem is solved via a model that combines two optimization approaches: stochastic optimal control and multi-stage stochastic programming. The first method is common in financial and actuarial literature, but produces theoretical results. However, the latter, which...
Development of Android based Smart Power Saving System
Gupta, Ashutosh; Kumar, Pradeep; Ghosh, Tathagata; Bhawna, Shruthi. S.
2017-08-01
An android based smart power saving system has been presented in this paper. For this purpose, an application is developed for controlling the intensity of an AC supply using a dimmer circuit in android platform and to monitor the current flow on different intensity level a current sensor is used in the circuit. Dimmer circuit provides a 16-different intensity level to control the flow of current and help in power saving. The system is very simple and robust as it is based on android platform.
Power, control and optimization
Vasant, Pandian; Barsoum, Nader
2013-01-01
The book consists of chapters based on selected papers of international conference „Power, Control and Optimization 2012”, held in Las Vegas, USA. Readers can find interesting chapters discussing various topics from the field of power control, its distribution and related fields. Book discusses topics like energy consumption impacted by climate, mathematical modeling of the influence of thermal power plant on the aquatic environment, investigation of cost reduction in residential electricity bill using electric vehicle at peak times or allocation and size evaluation of distributed generation using ANN model and others. Chapter authors are to the best of our knowledge the originators or closely related to the originators of presented ideas and its applications. Hence, this book certainly is one of the few books discussing the benefit from intersection of those modern and fruitful scientific fields of research with very tight and deep impact on real life and industry. This book is devoted to the studies o...
Energy-saving decomposition and power consumption forecast: The case of liaoning province in China
Energy Technology Data Exchange (ETDEWEB)
He, Y.X.; Zhao, Y.S.; Wang, Y.J. [School of Business Administration, North China Electric Power University, Zhu Xin Zhuang, Bei Nong Lu No. 2, Changping District, Beijing (China); Zhang, S.L. [Finance Department, Nanning Power Supply Bureau, Xingguang Street No. 43, Nanning, Guangxi Autonomous Region (China); Li, F.R. [University of Bath, Bath, BA2 7AY (United Kingdom)
2011-01-15
To achieve sustainable development of the society, the People's Republic of China (PRC) proposed in its 11th Five-Year Plan for National Economic and Social Development Program a shift in energy-saving target of decreasing energy intensity by 20% in 2010 compared with that of 2005. Liaoning province is one of the oldest industrial bases in China. Policymakers are often confronted with problems relating to adjustment in the development pattern as a means to secure steady economic growth. The power industry is a fundamental energy industry; it plays an important role in realizing of energy-saving targets. Based on the input-output model, this paper sets extensive, planning and 20% energy-saving scenarios in order to analyze energy-saving and power consumption situations for Liaoning by 2010. Through extensive simulations, the levels of energy-saving and power demand under different scenarios are obtained. Results from the analysis show that under the premises of adjusting the ratio of investment and consumption, optimizing products structure, and improving energy use efficiency, it is possible to achieve the proposed energy-saving target. Liaoning's power consumption can maintain a stable growth trend in the future. The percentage of electricity to the total energy use can also increase to 16% in 2010. (author)
Saving Energy and Money: A Lesson in Computer Power Management
Lazaros, Edward J.; Hua, David
2012-01-01
In this activity, students will develop an understanding of the economic impact of technology by estimating the cost savings of power management strategies in the classroom. Students will learn how to adjust computer display settings to influence the impact that the computer has on the financial burden to the school. They will use mathematics to…
Novel power saving architecture for FBG based OCDMA code generation
Osadola, Tolulope B.; Idris, Siti K.; Glesk, Ivan
2013-10-01
A novel architecture for generating incoherent, 2-dimensional wavelength hopping-time spreading optical CDMA codes is presented. The architecture is designed to facilitate the reuse of optical source signal that is unused after an OCDMA code has been generated using fiber Bragg grating based encoders. Effective utilization of available optical power is therefore achieved by cascading several OCDMA encoders thereby enabling 3dB savings in optical power.
Potential Energy Savings in Refrigeration Systems Using Optimal Setpoints
DEFF Research Database (Denmark)
Larsen, Lars Finn Slot; Thybo, Claus
2004-01-01
Energy efficiency of refrigeration systems has gradually been improved with help of control schemes utilizing the more flexible components. This paper proposes an approach in line with this trend, where a suboptimal condenser pressure is found in order to minimize the energy consumption. The obje......Energy efficiency of refrigeration systems has gradually been improved with help of control schemes utilizing the more flexible components. This paper proposes an approach in line with this trend, where a suboptimal condenser pressure is found in order to minimize the energy consumption....... The objective is to give an idea of how this optimization scheme works as well as to show what amount of energy it is possible to save. A steady state model of a simple refrigeration system will be used as a basis for the optimization....
Thermodynamic optimization of power plants
Haseli, Y.
2011-01-01
Thermodynamic Optimization of Power Plants aims to establish and illustrate comparative multi-criteria optimization of various models and configurations of power plants. It intends to show what optimization objectives one may define on the basis of the thermodynamic laws, and how they can be applied
Material saving by means of CWR technology using optimization techniques
Pérez, Iñaki; Ambrosio, Cristina
2017-10-01
Material saving is currently a must for the forging companies, as material costs sum up to 50% for parts made of steel and up to 90% in other materials like titanium. For long products, cross wedge rolling (CWR) technology can be used to obtain forging preforms with a suitable distribution of the material along its own axis. However, defining the correct preform dimensions is not an easy task and it could need an intensive trial-and-error campaign. To speed up the preform definition, it is necessary to apply optimization techniques on Finite Element Models (FEM) able to reproduce the material behaviour when being rolled. Meta-models Assisted Evolution Strategies (MAES), that combine evolutionary algorithms with Kriging meta-models, are implemented in FORGE® software and they allow reducing optimization computation costs in a relevant way. The paper shows the application of these optimization techniques to the definition of the right preform for a shaft from a vehicle of the agricultural sector. First, the current forging process, based on obtaining the forging preform by means of an open die forging operation, is showed. Then, the CWR preform optimization is developed by using the above mentioned optimization techniques. The objective is to reduce, as much as possible, the initial billet weight, so that a calculation of flash weight reduction due to the use of the proposed preform is stated. Finally, a simulation of CWR process for the defined preform is carried out to check that most common failures (necking, spirals,..) in CWR do not appear in this case.
Intelligent control of energy-saving power generation system
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhiyuan; Zhang, Guoqing; Guo, Zhizhong [Harbin Institute of Technology, Harbin (China). Dept. of Electrical Engineering
2013-07-01
Highway power generation system which is environmentally friendly and sustainable provides an innovative method of energy conversion. It is also as a kind of city science and technology innovation, which has the characteristics of environmental protection and sustainable utilization. Making full use of vehicle impact speed control humps, we design a new kind of highway speed control humps combined with solar electric generation system integration. Developing green energy, energy saving and environment protection can be achieved.
How EPRI [Electric Power Research Institute] helps utilities save money
International Nuclear Information System (INIS)
Anon.
1996-01-01
A number of case studies are presented which illustrate how the work of the Electric Power Research Institute in the USA has enabled nuclear utilities to save money. The areas covered by the examples are: steam generator tube repair; streamlining of reliability centred maintenance; cost effective instrumentation and control maintenance; reducing the frequency of instrument calibration; optimising the engineering change process; detecting and reducing fuel failure; extending the qualified life of equipment. (U.K.)
Metaheuristic optimization in power engineering
Radosavljević, Jordan
2018-01-01
This book describes the principles of solving various problems in power engineering via the application of selected metaheuristic optimization methods including genetic algorithms, particle swarm optimization, and the gravitational search algorithm.
Load flow optimization and optimal power flow
Das, J C
2017-01-01
This book discusses the major aspects of load flow, optimization, optimal load flow, and culminates in modern heuristic optimization techniques and evolutionary programming. In the deregulated environment, the economic provision of electrical power to consumers requires knowledge of maintaining a certain power quality and load flow. Many case studies and practical examples are included to emphasize real-world applications. The problems at the end of each chapter can be solved by hand calculations without having to use computer software. The appendices are devoted to calculations of line and cable constants, and solutions to the problems are included throughout the book.
Evaluation of Different Power Saving Techniques for MBMS Services
Directory of Open Access Journals (Sweden)
Antonios Alexiou
2009-01-01
Full Text Available Over the last years we have witnessed an explosive growth of multimedia computing, wireless communication and applications. Following the rapid increase in penetration rate of broadband services, the Third Generation Partnership Project (3GPP is currently standardizing the Evolved-Multimedia Broadcast/Multicast Service (E-MBMS framework of Long Term Evolution (LTE, the successor of Universal Mobile Telecommunications System (UMTS. MBMS constitutes a point-to-multipoint downlink bearer service that was designed to significantly decrease the required radio and wired link resources. However, several obstacles regarding the high-power requirements should be overcome for the realization of MBMS. Techniques, such as Macrodiversity Combining and Rate Splitting, could be utilized to reduce the power requirement of delivering multicast traffic to MBMS users. In this paper, we analytically present several power saving techniques and analyze their performance in terms of power consumption. We provide simulation results that reveal the amount of power that is saved and reinforce the need for the usage of such techniques.
Energy saved neon sign lighting power supply for photovoltaic systems
Energy Technology Data Exchange (ETDEWEB)
Tanitteerapan, T.; Dokpikul, S.; Arunrungrasmi, S. [King Mongkut Univ. of Technology Thonburi, Bangmod, Tungkru, Bangkok (Thailand). Dept. of Electrical Technology Education, Faculty of Industrial Education
2007-07-01
Petroleum oil, natural gas and fossil fuels are commonly used in power plants for electrical power generation. However, because of their negative environmental impacts, energy and environmental savings from renewable energy resources are necessary choices. Solar energy can be converted to the electrical voltage by using solar arrays. This process can be used in many electrical applications. This paper introduced a neon sign lighting power supply for a small photovoltaic powered stand-alone commercial advertising board for a remote area in Thailand. The circuit implementation was very simple, consisting of an active switch device, a resonant capacitor and high frequency transformer. The control also operated as a fixed frequency and fixed duty ratio controller. The paper discussed the principle of neon sign lighting, power circuit operation, and control circuit operation. To verify the proposed power supply, the circuit experiment of the proposed power supply for the neon sign lighting was applied to a 10 foot long, 10 millimeter diameter bulb. The neon sign was ignited smoothly with little power consumption. 2 refs., 1 tab., 10 figs.
Flapping wing flight can save aerodynamic power compared to steady flight.
Pesavento, Umberto; Wang, Z Jane
2009-09-11
Flapping flight is more maneuverable than steady flight. It is debated whether this advantage is necessarily accompanied by a trade-off in the flight efficiency. Here we ask if any flapping motion exists that is aerodynamically more efficient than the optimal steady motion. We solve the Navier-Stokes equation governing the fluid dynamics around a 2D flapping wing, and determine the minimal aerodynamic power needed to support a specified weight. While most flapping wing motions are more costly than the optimal steady wing motion, we find that optimized flapping wing motions can save up to 27% of the aerodynamic power required by the optimal steady flight. We explain the cause of this energetic advantage.
On optimization of power production
Energy Technology Data Exchange (ETDEWEB)
Feltenmark, S.
1997-01-01
Short-term optimization of power production is treated. It concerns the problem of determining a production schedule for a power system, which minimizes the total cost of production, while satisfying various constraints. The thesis consists of an introductory chapter, four chapters that each concerns a specific problem area (economic dispatch, unit commitment, hydro power planning and cogeneration optimization), plus a chapter with relevant theory. The emphasis of the thesis is on the mathematical structures that arise in problems in this field, and how to exploit them algorithmically. A recurring theme is convexification, either implicit, by dualization, or explicit, as in our approach to hydro power optimization. 134 refs
Maximum power point tracking: a cost saving necessity in solar energy systems
Energy Technology Data Exchange (ETDEWEB)
Enslin, J H.R. [Stellenbosch Univ. (South Africa). Dept. of Electrical and Electronic Engineering
1992-12-01
A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking (MPPT) can improve cost effectiveness, has a higher reliability and can improve the quality of life in remote areas. A high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of between 15 and 25% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply (RAPS) systems. The advantages at large temperature variations and high power rated systems are much higher. Other advantages include optimal sizing and system monitor and control. (author).
Optimization of power system operation
Zhu, Jizhong
2015-01-01
This book applies the latest applications of new technologies topower system operation and analysis, including new and importantareas that are not covered in the previous edition. Optimization of Power System Operation covers both traditional andmodern technologies, including power flow analysis, steady-statesecurity region analysis, security constrained economic dispatch,multi-area system economic dispatch, unit commitment, optimal powerflow, smart grid operation, optimal load shed, optimalreconfiguration of distribution network, power system uncertaintyanalysis, power system sensitivity analysis, analytic hierarchicalprocess, neural network, fuzzy theory, genetic algorithm,evolutionary programming, and particle swarm optimization, amongothers. New topics such as the wheeling model, multi-areawheeling, the total transfer capability computation in multipleareas, are also addressed. The new edition of this book continues to provide engineers andac demics with a complete picture of the optimization of techn...
International Nuclear Information System (INIS)
Kitada, Atsuko
2004-01-01
The shutdown of a number of nuclear power stations of the Tokyo Electric Power Company in the summer of 2003 caused a power shortage problem in the Tokyo Metropolitan area. To examine the effects of the power shortage, in September 2003 a survey was conducted in the service areas of the Kansai Electric Power Company (Kansai region) and the Tokyo Electric Power Company (Kanto region). This survey was part of a wider opinion survey begun in 1993 concerning nuclear power generation. The results of the September 2003 survey are as follows: The degree of recognition of the power shortage problem in the Metropolitan area was high, with 40% of respondents in the Kansai region and nearly 70% in the Kanto region understanding that the shortage was caused by the shutdown of several nuclear power station. The overall awareness of nuclear power generation was little affected in both the Kansai and Kanto regions, though the sense of a shortage of the generating capacity had been raised slightly. Once respondents knew about the power shortage problem, they estimated the likelihood of an occurrence of large-scale service interruption to be low, nearly at an even chance, and they had been only slightly worried about it, essentially viewing the problem optimistically. In the Kanto region, where public relations activities for power savings had been actively pursued, the frequency of experiencing exposure to such public relations activities was remarkably higher than in the Kansai region. The relation between exposure to public relations activities for power savings and power savings behavior was analyzed using quantification method II. Analysis results suggest that public relations activities for power savings in the Kanto region had the effect of urging power savings behavior. However, the difference in the rate of putting power savings behavior into practice was small between the Kanto and Kansai regions, indicating that public relation activities for power savings in the Kanto
Evolution strategy based optimal chiller loading for saving energy
International Nuclear Information System (INIS)
Chang, Y.-C.; Lee, C.-Y.; Chen, C.-R.; Chou, C.-J.; Chen, W.-H.; Chen, W.-H.
2009-01-01
This study employs evolution strategy (ES) to solve optimal chiller loading (OCL) problem. ES overcomes the flaw that Lagrangian method is not adaptable for solving OCL as the power consumption models or the kW-PLR (partial load ratio) curves include convex functions and concave functions simultaneously. The complicated process of evolution by the genetic algorithm (GA) method for solving OCL can also be simplified by the ES method. This study uses the PLR of chiller as the variable to be solved for the decoupled air conditioning system. After analysis and comparison of the case study, it has been concluded that this method not only solves the problems of Lagrangian method and GA method, but also produces results with high accuracy within a rapid timeframe. It can be perfectly applied to the operation of air conditioning systems
Electric Power Saving Awareness System at School Using ICT
Directory of Open Access Journals (Sweden)
Kuzume Koichi
2016-01-01
Full Text Available Nowadays, education on energy saving at schools attracts attention to reduce energy consumption. In this paper we proposed a novel system to promote energy conservation activity at schools using a sensor network. The system consisted of a wall-type clock embedded with several kinds of sensors for temperature and light in the classroom, and wireless devices to connect to a cloud computer network. The system had the following superiorities: offered various services for energy conservation activity, needless of CT (Current Transformer sensor, low price, ease of installation and extension, and visualization of power consumption in conjunction with school timetable in real time. We presented the system and a user study conducted to evaluate its usefulness.
Fast Control Channel Decoding for LTE UE Power Saving
DEFF Research Database (Denmark)
Lauridsen, Mads; Jensen, Anders Riis; Mogensen, Preben
2012-01-01
in the current TTI. The cost is that some reference signals are not received leading to a degraded channel estimate. Calculations show that this causes an SINR degradation of approximately 0.5 dB, which will result in maximum 4 % throughput loss. Comparing this with energy saving potentials of 5 %-25...... % it is concluded that the FCCD method is a valuable aid to prolong LTE phones' battery lifetime. The results are generated using a two state Markov chain model to simulate traffic and scheduling, and verified mathematically. The work also includes an examination of various data traffic types' on/off relation...... and an evaluation of how the relation affects power consumption. The FCCD method can complement DRX sleep mode since it is applicable when the signal is too aperiodic or fast switching for DRX....
An Indispensable Truth How Fusion Power Can Save the Planet
Chen, Francis F
2011-01-01
Both global warming and oil shortage can be solved by controlled fusion, a clean power source that will serve mankind for millennia.� The idea of hydrogen fusion as well as its difficulties are presented in non-technical language to dispel the notion that fusion is always 50 years away.� This book also summarizes the evidence for climate change and explains the principles of both fossil and "green" energy sources to show that fusion is the best alternative for central-station power in the near term as well as the far future. Praise for An Indispensable Truth: How Fusion Power Can Save the Planet: "In this study Professor Chen outlines the underlying physics, recent progress in achieving advanced plasmas and magnetic confinement, and hopes for the future. He recognizes the difficulties that remain in engineering a fusion reactor, but he remains optimistic regarding ultimate success, yet fearful of the consequences were we to fail."- James R. Schlesinger, former Chairman, Atomic Energy Commission; Director,...
Evolution of China's power dispatch principle and the new energy saving power dispatch policy
International Nuclear Information System (INIS)
Ciwei, Gao; Yang, Li
2010-01-01
With social economic reform in the past decades, the power industry of China is gradually evolving from a highly integrated one toward an electricity market, which can be characterized based on the transition of the power dispatch principle. To attract investment in the power generating industry, China introduced non-state-owned power plants to the original system of a highly vertically integrated power industry with annual power generation quota guarantees, which makes the traditional economic dispatch principle not applicable. The newly debuted energy saving power dispatch (ESPD) is an attempt to fully exploit the maximum energy savings and was implemented by an administrative code. Starting in August 2007, the pilot operation of the ESPD was implemented in five provinces, but after two years, it is still not widely applied all over the country. This paper details the transition of China's power dispatch principle with particular attention to its origin and content. Moreover, the factors that influence the ESPD's actual energy saving effect are discussed, as well as the sustainability of the policy. (author)
Force analysis of magnetic bearings with power-saving controls
International Nuclear Information System (INIS)
Johnson, D.; Brown, G.V.; Inman, D.J.
1992-01-01
Most magnetic bearing control schemes use a bias current with a superimposed control current to linearize the relationship between the control current and the force it delivers. For most operating conditions, the existence of the bias current requires more power than alternative methods that do not use conventional bias. Two such methods are examined which diminish or eliminate bias current. In the typical bias control scheme it is found that for a harmonic control force command into a voltage limited transconductance amplifier, the desired force output is obtained only up to certain combinations of force amplitude and frequency. Above these values, the force amplitude is reduced and a phase lag occurs. The power saving alternative control schemes typically exhibit such deficiencies at even lower command frequencies and amplitudes. To assess the severity of these effects, a time history analysis of the force output is performed for the bias method and the alternative methods. Results of the analysis show that the alternative approaches may be viable. The various control methods examined were mathematically modeled using nondimensionalized variables to facilitate comparison of the various methods
A Location Selection Policy of Live Virtual Machine Migration for Power Saving and Load Balancing
Directory of Open Access Journals (Sweden)
Jia Zhao
2013-01-01
Full Text Available Green cloud data center has become a research hotspot of virtualized cloud computing architecture. And load balancing has also been one of the most important goals in cloud data centers. Since live virtual machine (VM migration technology is widely used and studied in cloud computing, we have focused on location selection (migration policy of live VM migration for power saving and load balancing. We propose a novel approach MOGA-LS, which is a heuristic and self-adaptive multiobjective optimization algorithm based on the improved genetic algorithm (GA. This paper has presented the specific design and implementation of MOGA-LS such as the design of the genetic operators, fitness values, and elitism. We have introduced the Pareto dominance theory and the simulated annealing (SA idea into MOGA-LS and have presented the specific process to get the final solution, and thus, the whole approach achieves a long-term efficient optimization for power saving and load balancing. The experimental results demonstrate that MOGA-LS evidently reduces the total incremental power consumption and better protects the performance of VM migration and achieves the balancing of system load compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.
A location selection policy of live virtual machine migration for power saving and load balancing.
Zhao, Jia; Ding, Yan; Xu, Gaochao; Hu, Liang; Dong, Yushuang; Fu, Xiaodong
2013-01-01
Green cloud data center has become a research hotspot of virtualized cloud computing architecture. And load balancing has also been one of the most important goals in cloud data centers. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on location selection (migration policy) of live VM migration for power saving and load balancing. We propose a novel approach MOGA-LS, which is a heuristic and self-adaptive multiobjective optimization algorithm based on the improved genetic algorithm (GA). This paper has presented the specific design and implementation of MOGA-LS such as the design of the genetic operators, fitness values, and elitism. We have introduced the Pareto dominance theory and the simulated annealing (SA) idea into MOGA-LS and have presented the specific process to get the final solution, and thus, the whole approach achieves a long-term efficient optimization for power saving and load balancing. The experimental results demonstrate that MOGA-LS evidently reduces the total incremental power consumption and better protects the performance of VM migration and achieves the balancing of system load compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.
International Nuclear Information System (INIS)
Liao, Gwo-Ching
2011-01-01
An optimization algorithm is proposed in this paper to solve the economic dispatch problem that includes wind farm using the Chaotic Quantum Genetic Algorithm (CQGA). In addition to the detailed models of economic dispatch introduction and their associated constraints, the wind power effect is also included in this paper. The chaotic quantum genetic algorithm used to solve the economic dispatch process and discussed with real scenarios used for the simulation tests. After comparing the proposed algorithm with several other algorithms commonly used to solve optimization problems, the results show that the proposed algorithm is able to find the optimal solution quickly and accurately (i.e. to obtain the minimum cost for power generation in the shortest time). At the end, the impact to the total cost savings for power generation after adding (or not adding) wind power generation is also discussed. The actual implementation results prove that the proposed algorithm is economical, fast and practical. They are quite valuable for further research. -- Research highlights: → Quantum Genetic Algorithm can effectively improve the global search ability. → It can achieve the real objective of the global optimal solutions. → The CPU computation time is less than that other algorithms adopted in this paper.
Power Saving Scheduling Scheme for Internet of Things over LTE/LTE-Advanced Networks
Directory of Open Access Journals (Sweden)
Yen-Wei Kuo
2015-01-01
Full Text Available The devices of Internet of Things (IoT will grow rapidly in the near future, and the power consumption and radio spectrum management will become the most critical issues in the IoT networks. Long Term Evolution (LTE technology will become a promising technology used in IoT networks due to its flat architecture, all-IP network, and greater spectrum efficiency. The 3rd Generation Partnership Project (3GPP specified the Discontinuous Reception (DRX to reduce device’s power consumption. However, the DRX may pose unexpected communication delay due to missing Physical Downlink Control Channel (PDCCH information in sleep mode. Recent studies mainly focus on optimizing DRX parameters to manage the tradeoff between the energy consumption and communication latency. In this paper, we proposed a fuzzy-based power saving scheduling scheme for IoT over the LTE/LTE-Advanced networks to deal with the issues of the radio resource management and power consumption from the scheduling and resource allocation perspective. The proposed scheme considers not only individual IoT device’s real-time requirement but also the overall network performance. The simulation results show that our proposed scheme can meet the requirements of the DRX cycle and scheduling latency and can save about half of energy consumption for IoT devices compared to conventional approaches.
Energy Saving and Efficient Energy Use By Power Electronic Systems
DEFF Research Database (Denmark)
Blaabjerg, Frede; Wang, Huai; Davari, Pooya
2017-01-01
In the development of the modern society, one of the key factors is to save energy in order to become more independent of other energy resources. Two important approaches can be taken—one is to change behavior and thereby save energy—the second one is to develop new technology which is able to sa...
International Nuclear Information System (INIS)
Zvingilaite, Erika
2013-01-01
A substantial untapped energy saving potential rests in the building sector and is expected to play an important role in achieving reduction of environmental impacts of energy. In order to utilise this potential, effective policy measures need to be adopted to remove the existing barriers and create incentives. For that purpose, the cost effective energy saving options together with an optimal level of savings and expected environmental benefits have to be identified. The paper reports on a study that analyses these questions by including heat-saving measures in buildings into an energy system optimisation model of the Danish heat and power sector. The achieved optimal level of heat savings reaches 11% of projected heat demand in 2025 under the model assumptions. Moreover, the analysis reveals the importance of considering energy conservation options in a system wide perspective. Furthermore, the results suggest that changes in the energy generation sector are the prime driver behind the reduction of environmental externalities of energy. Heat savings in buildings play only a small role under model assumptions. - Highlights: ► Heat savings in buildings are analysed together with a heat and power system. ► Heat savings compete with electricity to heat technologies, mainly heat pumps. ► Cost effective heat-savings bring small decrease in health impacts and CO 2 emissions. ► Cost-effectiveness of heat savings depends on the marginal heat generation technology
Use a renewable energy sources and latest power-saving technologies in the the Republic Kazakstan
International Nuclear Information System (INIS)
Gulevich, N.V.
1996-01-01
The subject of alternative power in Kazakstan is brought up. Wind-, hydro-, solar power, biogas installation can improve the Republic power base. The main directions of activity of A. Einstein International Power engineering Academy on involving renewable energy sources and latest power-saving technologies to Republic of Kazakstan's fuel-power balance is given. It should be noted that renewable power engineering usually handles reversible energy sources and reserved power cycles. (author)
Enersave API: Android-based power-saving framework for mobile devices
Directory of Open Access Journals (Sweden)
A.M. Muharum
2017-06-01
Full Text Available Power consumption is a major factor to be taken into consideration when using mobile devices in the IoT field. Good Power management requires proper understanding of the way in which it is being consumed by the end-devices. This paper is a continuation of the work in Ref. [1] and proposes an energy saving API for the Android Operating System in order to help developers turn their applications into energy-aware ones. The main features heavily used for building smart applications, greatly impact battery life of Android devices and which have been taken into consideration are: Screen brightness, Colour scheme, CPU frequency, 2G/3G network, Maps, Low power localisation, Bluetooth and Wi-Fi. The assessment of the power-saving API has been performed on real Android devices and also compared to the most powerful power-saving applications – DU Battery Saver and Battery Saver 2016 – currently available on the Android market. Comparisons demonstrate that the Enersave API has a significant impact on power saving when incorporated in android applications. While DU Battery Saver and Battery Saver 2016 help saving 22.2% and 40.5% of the battery power respectively, the incorporation of the Enersave API in android applications can help save 84.6% of battery power.
Vattenfall want to save money: will run Ringhals 3 and 4 with reduced power
International Nuclear Information System (INIS)
Anon.
1982-01-01
Ringhals 3 and 4 are nuclear power stations which require re-design before full power can be generated. To save money both stations will be running at reduced power during 1982 to generate power and gain running experience. (J.H.)
International Nuclear Information System (INIS)
Bouchekara, H.R.E.H.; Abido, M.A.; Chaib, A.E.; Mehasni, R.
2014-01-01
Highlights: • Optimal power flow. • Reducing electrical energy loss. • Saving electrical energy. • Optimal operation. - Abstract: A new efficient optimization method, called the League Championship Algorithm (LCA) is proposed in this paper for solving the optimal power flow problem. This method is inspired by the competition of sport teams in an artificial sport league for several weeks and over a number of seasons. The proposed method has been applied to the Algerian power system network for different objectives. Furthermore, in order to assess the effectiveness of the proposed LCA method the obtained results using this method have been compared to those obtained using other methods reported in the literature. The obtained results and the comparison with other techniques indicate that the league championship algorithm provides effective and high-quality solution when solving the optimal power flow problem
Johar, F. M.; Azmin, F. A.; Shibghatullah, A. S.; Suaidi, M. K.; Ahmad, B. H.; Abd Aziz, M. Z. A.; Salleh, S. N.; Shukor, M. Md
2014-04-01
Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.
International Nuclear Information System (INIS)
Johar, F M; Azmin, F A; Suaidi, M K; Ahmad, B H; Aziz, M Z A Abd; Salleh, S N; Shukor, M Md; Shibghatullah, A S
2014-01-01
Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.
Effect of energy saving lights on power supply
Timens, R.B.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes
2012-01-01
Weak power supply networks are very sensitive to non-linear low power loads. Electronics in low power loads are non-linear, very basic, and consisting of a rectifier bridge and bulk capacitor, consuming current only in the peak of the supplied voltage. Due to the relative high power supply network
Dixit, Abhishek; Lannoo, Bart; Colle, Didier; Pickavet, Mario; Demeester, Piet
2012-12-10
The optical network unit (ONU), installed at a customer's premises, accounts for about 60% of power in current fiber-to-the-home (FTTH) networks. We propose a power consumption model for the ONU and evaluate the ONU power consumption in various next generation optical access (NGOA) architectures. Further, we study the impact of the power savings of the ONU in various low power modes such as power shedding, doze and sleep.
Social Optimization and Pricing Policy in Cognitive Radio Networks with an Energy Saving Strategy
Directory of Open Access Journals (Sweden)
Shunfu Jin
2016-01-01
Full Text Available The rapid growth of wireless application results in an increase in demand for spectrum resource and communication energy. In this paper, we firstly introduce a novel energy saving strategy in cognitive radio networks (CRNs and then propose an appropriate pricing policy for secondary user (SU packets. We analyze the behavior of data packets in a discrete-time single-server priority queue under multiple-vacation discipline. With the help of a Quasi-Birth-Death (QBD process model, we obtain the joint distribution for the number of SU packets and the state of base station (BS via the Matrix-Geometric Solution method. We assess the average latency of SU packets and the energy saving ratio of system. According to a natural reward-cost structure, we study the individually optimal behavior and the socially optimal behavior of the energy saving strategy and use an optimization algorithm based on standard particle swarm optimization (SPSO method to search the socially optimal arrival rate of SU packets. By comparing the individually optimal behavior and the socially optimal behavior, we impose an appropriate admission fee to SU packets. Finally, we present numerical results to show the impacts of system parameters on the system performance and the pricing policy.
Energy-saving management modelling and optimization for lead-acid battery formation process
Wang, T.; Chen, Z.; Xu, J. Y.; Wang, F. Y.; Liu, H. M.
2017-11-01
In this context, a typical lead-acid battery producing process is introduced. Based on the formation process, an efficiency management method is proposed. An optimization model with the objective to minimize the formation electricity cost in a single period is established. This optimization model considers several related constraints, together with two influencing factors including the transformation efficiency of IGBT charge-and-discharge machine and the time-of-use price. An example simulation is shown using PSO algorithm to solve this mathematic model, and the proposed optimization strategy is proved to be effective and learnable for energy-saving and efficiency optimization in battery producing industries.
Chevrier , Rémy
2010-01-01
International audience; An approach for speed tuning in railway management is presented for optimizing both travel duration and energy saving. This approach is based on a state-of-the-art evolutionary algorithm with Pareto approach. This algorithm provides a set of diversified non-dominated solutions to the decision-maker. A case study on Gonesse connection (France) is also reported and analyzed.
DEFF Research Database (Denmark)
Larsen, Lars Finn Sloth; Thybo, Claus; Wisniewski, Rafal
2007-01-01
The objective of this study is to investigate the energy saving potential for refrigeration systems by refrigeration more at the colder night time than at the warmer day time. The potential is evaluated using an optimal control policy and illustrated on a simulation example. The results show...
Holiday homes - electric power savings; Sommerhuse - elbesparelser her og nu
Energy Technology Data Exchange (ETDEWEB)
Kofoed Esbensen, N -U; Roed Rasmussen, E [Esbensen Raadgivende Ingenioerer A/S, Copenhagen (Denmark); Weldingh, P [Lokalenergi, Viby J. (Denmark); Worm, J; Adams Rasmussen, L [Energitjenesten, Aarhus (Denmark); Reuss, M [Elsparefonden, Copenhagen (Denmark); Ellehauge, K; Kjaergaard, C -J [Ellehauge og Kildemoes, Aarhus (Denmark); Jensen, Ole Michael [Aalborg Univ. SBi, Aalborg (Denmark)
2010-09-15
A questionnaire survey among 700 holiday home owners was conducted and followed up by interviews with representatives of typical groups of holiday home owners and a number of key persons representing rental, building, electricity supply, regulatory processing and supply of renewable energy facilities to holiday homes. The results of the questionnaire survey and of former surveys on technical savings potential are included in an easy-to-read catalogue of ideas with directions and recommendations for various groups of holiday home users and players. The recommendations are grouped into eight topics of more or less relevance for the various target groups. (LN)
Security constrained optimal power flow by modern optimization tools
African Journals Online (AJOL)
The main objective of an optimal power flow (OPF) functions is to optimize .... It is characterized as propagation of plants and this happens by gametes union. ... ss and different variables, for example, wind, nearby fertilization can have a critic.
Electric power system applications of optimization
Momoh, James A
2008-01-01
Introduction Structure of a Generic Electric Power System Power System Models Power System Control Power System Security Assessment Power System Optimization as a Function of Time Review of Optimization Techniques Applicable to Power Systems Electric Power System Models Complex Power Concepts Three-Phase Systems Per Unit Representation Synchronous Machine Modeling Reactive Capability Limits Prime Movers and Governing Systems Automatic Gain Control Transmission Subsystems Y-Bus Incorporating the Transformer Effect Load Models Available Transfer Capability Illustrative Examples Power
Optimizing Energy Savings from Direct-DC in U.S. Residential Buildings
Energy Technology Data Exchange (ETDEWEB)
Garbesi, Karina; Vossos, Vagelis; Sanstad, Alan; Burch, Gabriel
2011-10-13
An increasing number of energy efficient appliances operate on direct current (DC) internally, offering the potential to use DC from renewable energy systems directly and avoiding the losses inherent in converting power to alternating current (AC) and back. This paper investigates that potential for net-metered residences with on-site photovoltaics (PV) by modeling the net power draw of the ‘direct-DC house’ with respect to today’s typical configuration, assuming identical DC-internal loads. Power draws were modeled for houses in 14 U.S. cities, using hourly, simulated PV-system output and residential loads. The latter were adjusted to reflect a 33% load reduction, representative of the most efficient DC-internal technology, based on an analysis of 32 electricity end-uses. The model tested the effect of climate, electric vehicle (EV) loads, electricity storage, and load shifting on electricity savings; a sensitivity analysis was conducted to determine how future changes in the efficiencies of power system components might affect savings potential. Based on this work, we estimate that net-metered PV residences could save 5% of their total electricity load for houses without storage and 14% for houses with storage. Based on residential PV penetration projections for year 2035 obtained from the National Energy Modeling System (2.7% for the reference case and 11.2% for the extended policy case), direct-DC could save the nation 10 trillion Btu (without storage) or 40 trillion Btu (with storage). Shifting the cooling load by two hours earlier in the day (pre-cooling) has negligible benefits for energy savings. Direct-DC provides no energy savings benefits for EV charging, to the extent that charging occurs at night. However, if charging occurred during the day, for example with employees charging while at work, the benefits would be large. Direct-DC energy savings are sensitive to power system and appliance conversion efficiencies but are not significantly
International Nuclear Information System (INIS)
Hashiba, Takashi
2001-01-01
In this research, relationship between people's awareness of environmental capabilities of saving energy, photovoltaic power generation (PV) and nuclear power generation was investigated using questionnaire method. The results showed that saving energy is conducted without reference to its environment preservation effect. However the older people tend to regard saving energy as contribution to environment preservation. The attitude toward usage of PV has a close relationship to awareness of energy environmental concerns. Acceptance of cost sharing for the introducing of wide-scale PV systems to society is related to environment protection image of PV and the attitude toward loss of social convenience lost as a result of saving energy activities. The older people become, the more priority people put on environment protection before the social convenience. There is little relationship between environmental capabilities of nuclear power generation, that never discharge CO 2 on generation, and awareness of energy environmental concerns. (author)
Energy Technology Data Exchange (ETDEWEB)
Hashiba, Takashi [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)
2001-09-01
In this research, relationship between people's awareness of environmental capabilities of saving energy, photovoltaic power generation (PV) and nuclear power generation was investigated using questionnaire method. The results showed that saving energy is conducted without reference to its environment preservation effect. However the older people tend to regard saving energy as contribution to environment preservation. The attitude toward usage of PV has a close relationship to awareness of energy environmental concerns. Acceptance of cost sharing for the introducing of wide-scale PV systems to society is related to environment protection image of PV and the attitude toward loss of social convenience lost as a result of saving energy activities. The older people become, the more priority people put on environment protection before the social convenience. There is little relationship between environmental capabilities of nuclear power generation, that never discharge CO{sub 2} on generation, and awareness of energy environmental concerns. (author)
Prospects of nuclear power in fossil fuel saving
International Nuclear Information System (INIS)
Chernavskij, S.Ya.
1984-01-01
Economic aspects of the World energy situation are considered. The growth in the world prices for energy and energy resources has demanded to reconstruct the structure of both consumers and primary energy resources. The nuclear power development is one of the most important aspects of this reconstruction. In connection with its development the acceptability of nuclear power technology and possible spheres of its application in different fields of power engineering are considered. When discussing these problems one pays the main attention to the psychological effect and potential measures for its compensation. A forecast estimate is given of specific capital investments in and expenditures on electric energy production for NPPs and conventional power stations for the considered period of 30 years. The estimates are differentiated for the European and Asian parts of the country. The problems of developing nuclear central heating-and-power plants and nuclear thermal stations are discussed. It is pointed out that presently no sufficient experience has been gained in their commerical operation to discuss for sure the prospects of their wide-scale utilization. Results of calculations are presented showing that in the range of high-temperature processes the use of electric energy based on the nuclear power development is more efficient than direct combustion of fossil fuel as estimated with respect to its export at the world market prices
Power shopping - practical advice and cost-saving alternatives
International Nuclear Information System (INIS)
Anthofer, J.
1999-01-01
Encore Energy Solutions is a power consulting company which operates in California, Alberta and Ontario. The company manages electricity portfolios, sells risk management instruments and works with end users to lower power costs. It also helps utilities manage the evolution to a competitive energy market. In this presentation, a series of overhead viewgraphs were used to explain the roles of different players in Ontario's electric power industry, including generators, retailers, distributors, wholesale sellers, transmitters, wholesale consumers, independent market operators (IMOs), and consultants. The challenges facing municipal electric utilities regarding the wires business and retail services were also discussed. The trends in today's evolving power market were highlighted. These included price elasticity, load dispatch, granularity, long- and short-term volatility, gas prices, day/night spread, transmission tariffs, congestion and cost of capital. A graph depicting volatility term structures for electricity, natural gas and crude oil suggests that instantaneous volatility of power is almost infinite. Issues regarding risk management in terms of shareholder's portfolio values were also discussed. 17 figs
Cost Savings of Nuclear Power with Total Fuel Reprocessing
International Nuclear Information System (INIS)
Solbrig, Charles W.; Benedict, Robert W.
2006-01-01
The cost of fast reactor (FR) generated electricity with pyro-processing is estimated in this article. It compares favorably with other forms of energy and is shown to be less than that produced by light water reactors (LWR's). FR's use all the energy in natural uranium whereas LWR's utilize only 0.7% of it. Because of high radioactivity, pyro-processing is not open to weapon material diversion. This technology is ready now. Nuclear power has the same advantage as coal power in that it is not dependent upon a scarce foreign fuel and has the significant additional advantage of not contributing to global warming or air pollution. A jump start on new nuclear plants could rapidly allow electric furnaces to replace home heating oil furnaces and utilize high capacity batteries for hybrid automobiles: both would reduce US reliance on oil. If these were fast reactors fueled by reprocessed fuel, the spent fuel storage problem could also be solved. Costs are derived from assumptions on the LWR's and FR's five cost components: 1) Capital costs: LWR plants cost $106/MWe. FR's cost 25% more. Forty year amortization is used. 2) The annual O and M costs for both plants are 9% of the Capital Costs. 3) LWR fuel costs about 0.0035 $/kWh. Producing FR fuel from spent fuel by pyro-processing must be done in highly shielded hot cells which is costly. However, the five foot thick concrete walls have the advantage of prohibiting diversion. LWR spent fuel must be used as feedstock for the FR initial core load and first two reloads so this FR fuel costs more than LWR fuel. FR fuel costs much less for subsequent core reloads ( 6 /MWe. The annual cost for a 40 year licensed plant would be 2.5 % of this or less if interest is taken into account. All plants will eventually have to replace those components which become radiation damaged. FR's should be designed to replace parts rather than decommission. The LWR costs are estimated to be 2.65 cents/kWh. FR costs are 2.99 cents/kWh for the first
Optimal power flow by particle swarm optimization with an aging ...
African Journals Online (AJOL)
In this paper, a particle swarm optimization (PSO) with an aging leader and challengers (ALC-PSO) is applied for the solution of OPF problem of power system. This study is implemented on modified IEEE 30-bus test power system with different objectives that reflect minimization of either fuel cost or active power loss or sum ...
Ant colony search algorithm for optimal reactive power optimization
Directory of Open Access Journals (Sweden)
Lenin K.
2006-01-01
Full Text Available The paper presents an (ACSA Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents’ approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical test bus system. The proposed approach is tested and compared to genetic algorithm (GA, Adaptive Genetic Algorithm (AGA.
Energy Technology Data Exchange (ETDEWEB)
Wendelborn, Horst [Danfoss GmbH, Offenbach (Germany)
2011-06-15
Danfoss has been delivering for 20 years the optimizing ADAP-KOOL(R) control system. It enables the store to save 30% of the yearly energy bill, compared to a store with electronic standard controls. Over years the stores took the cheap standard solution, but now several German supermarket chains decide to take the best for the investment and lifecycle cost. This article describes the main control circuits and shows the measurements of the energy consumption of two stores with standard and optimized controls. This control system is available for chemical and for the natural refrigerant R744. (orig.)
UES: an optimization software package for power and energy
International Nuclear Information System (INIS)
Vohryzek, J.; Havlena, V.; Findejs, J.; Jech, J.
2004-01-01
Unified Energy Solutions components are designed to meet specific requirements of the electric utilities, industrial power units, and district heating (combined heat and power) plants. The optimization objective is to operate the plant with maximum process efficiency and operational profit under the constraints imposed by technology and environmental impacts. Software applications for advanced control real-time optimization may provide a low-cost, high return alternative to expensive boiler retrofits for improving operational profit as well as reducing emissions. Unified Energy Solutions (UES) software package is a portfolio of advanced control and optimization components running on top of the standard process regulatory and control system. The objective of the UES is to operate the plant with maximum achievable profit (maximum efficiency) under the constraints imposed by technology (life-time consumption, asset health) and environmental impacts (CO and NO x emissions). Fast responsiveness to varying economic conditions and integration of real-time optimization and operator decision support (off-line) features are critical for operation in real-time economy. Optimization Features are targeted to combustion process, heat and power load allocation to parallel resources, electric power delivery and ancillary services. Optimization Criteria include increased boiler thermal efficiency, maintaining emission limits, economic load allocation of the heat and generation sources. State-of-the-art advanced control algorithms use model based predictive control principles and provide superior response in transient states. Individual software modules support open control platforms and communication protocols. UES can be implemented on a wide range of distributed control systems. Typical achievable benefits include heat and power production costs savings, increased effective boiler operation range, optimized flue gas emissions, optimized production capacity utilization, optimized
AutoPowerOff plug banks - a story with energy saving perspectives
Energy Technology Data Exchange (ETDEWEB)
Hjort Jensen, Anders (The Danish Electricity Saving Trust (Denmark)); Fjordbak, Troels (IT Energy ApS (Denmark))
2009-07-01
Denmark uses around 35 TWh of electricity per year, with residential dwellings accounting for around 10 TWh of this figure. Standby consumption comprises around 12% of power used in homes. If every Danish home installed AutoPowerOff plug banks, savings exceeding 500 GWh per year would be possible, equivalent to 5% of household electricity consumption, or 1.5% of the total in Denmark. This paper describes the estimated standby consumption in Danish homes in 2006, and possible energy savings through the use of AutoPowerOff plug banks. The estimates were subsequently used as background information for a 2007-2008 campaign to promote the wider use of these devices in Denmark. In order to increase the sale of AutoPowerOff plug banks by 1 million units, it was agreed that retail chains selling consumer electronics would include an AutoPowerOff when selling a TV or PC. A nationwide TV advertising campaign was launched featuring the names of participating retailers. Sales of AutoPowerOff plug banks in the first 7 months of 2008 passed the 515,000 mark, with over 1 million units now installed in 2.5 million Danish households. Annual savings are estimated to be over 80 GWh, equivalent to 40,000 tons of CO{sub 2}. This equates to potential savings on an EU-wide basis of more than 7 TWh, or 3.6 million tons of CO{sub 2} in Denmark.
Directory of Open Access Journals (Sweden)
Fei Lin
2016-03-01
Full Text Available With its large capacity, the total urban rail transit energy consumption is very high; thus, energy saving operations are quite meaningful. The effective use of regenerative braking energy is the mainstream method for improving the efficiency of energy saving. This paper examines the optimization of train dwell time and builds a multiple train operation model for energy conservation of a power supply system. By changing the dwell time, the braking energy can be absorbed and utilized by other traction trains as efficiently as possible. The application of genetic algorithms is proposed for the optimization, based on the current schedule. Next, to validate the correctness and effectiveness of the optimization, a real case is studied. Actual data from the Beijing subway Yizhuang Line are employed to perform the simulation, and the results indicate that the optimization method of the dwell time is effective.
Artificial intelligence in power system optimization
Ongsakul, Weerakorn
2013-01-01
With the considerable increase of AI applications, AI is being increasingly used to solve optimization problems in engineering. In the past two decades, the applications of artificial intelligence in power systems have attracted much research. This book covers the current level of applications of artificial intelligence to the optimization problems in power systems. This book serves as a textbook for graduate students in electric power system management and is also be useful for those who are interested in using artificial intelligence in power system optimization.
Optimized PWR power ascension reload testing
International Nuclear Information System (INIS)
Emery, S.P.; Long, S.W.; Nazareth, V.F.; Herschthal, M.A.
1987-01-01
Reduction in critical path testing time following refueling is actively supported by utilities to increase plant capacity factor and to minimize replacement power costs. Combustion Engineering (C-E) has developed a fast power ascension program (FPAP), which reduces this critical path testing by minimizing holds at intermediate power levels and by automating data acquisition and analysis. A very successful demonstration of the FPAP was performed recently during the cycle 3 startup of Southern California Edison's San Onofre Unit 2 reactor, which resulted in a critical path time savings of ∼ 3 days
A Study on the Optimal Duration of Daylight Saving Time (DST in Korea
Directory of Open Access Journals (Sweden)
Byeong-Hee Mihn
2009-09-01
Full Text Available Daylight saving time aims at spending effective daylight in summer season. Korea had enforced daylight saving time twelve times from 1948 to 1988. Since 1988, it is not executed, but it is recently discussed the resumption of DST. In this paper, we investigate the trend of DST in other countries, review the history of DST in Korea, and suggest the optimal DST duration in terms of astronomical aspects (times of sunrise and sunset. We find that the starting day of DST in Korea is apt for the second Sunday in Mayor the second Sunday in April according to the time of sunrise or to the difference between Korean standard meridian and observer`s, respectively. We also discuss time friction that might be caused by time difference between DST and Korea Standard Time (KST.
Optimizing Wellfield Operation in a Variable Power Price Regime.
Bauer-Gottwein, Peter; Schneider, Raphael; Davidsen, Claus
2016-01-01
Wellfield management is a multiobjective optimization problem. One important objective has been energy efficiency in terms of minimizing the energy footprint (EFP) of delivered water (MWh/m(3) ). However, power systems in most countries are moving in the direction of deregulated markets and price variability is increasing in many markets because of increased penetration of intermittent renewable power sources. In this context the relevant management objective becomes minimizing the cost of electric energy used for pumping and distribution of groundwater from wells rather than minimizing energy use itself. We estimated EFP of pumped water as a function of wellfield pumping rate (EFP-Q relationship) for a wellfield in Denmark using a coupled well and pipe network model. This EFP-Q relationship was subsequently used in a Stochastic Dynamic Programming (SDP) framework to minimize total cost of operating the combined wellfield-storage-demand system over the course of a 2-year planning period based on a time series of observed price on the Danish power market and a deterministic, time-varying hourly water demand. In the SDP setup, hourly pumping rates are the decision variables. Constraints include storage capacity and hourly water demand fulfilment. The SDP was solved for a baseline situation and for five scenario runs representing different EFP-Q relationships and different maximum wellfield pumping rates. Savings were quantified as differences in total cost between the scenario and a constant-rate pumping benchmark. Minor savings up to 10% were found in the baseline scenario, while the scenario with constant EFP and unlimited pumping rate resulted in savings up to 40%. Key factors determining potential cost savings obtained by flexible wellfield operation under a variable power price regime are the shape of the EFP-Q relationship, the maximum feasible pumping rate and the capacity of available storage facilities. © 2015 The Authors. Groundwater published by Wiley
AS Migration and Optimization of the Power Integrated Data Network
Zhou, Junjie; Ke, Yue
2018-03-01
In the transformation process of data integration network, the impact on the business has always been the most important reference factor to measure the quality of network transformation. With the importance of the data network carrying business, we must put forward specific design proposals during the transformation, and conduct a large number of demonstration and practice to ensure that the transformation program meets the requirements of the enterprise data network. This paper mainly demonstrates the scheme of over-migrating point-to-point access equipment in the reconstruction project of power data comprehensive network to migrate the BGP autonomous domain to the specified domain defined in the industrial standard, and to smooth the intranet OSPF protocol Migration into ISIS agreement. Through the optimization design, eventually making electric power data network performance was improved on traffic forwarding, traffic forwarding path optimized, extensibility, get larger, lower risk of potential loop, the network stability was improved, and operational cost savings, etc.
The Optimization of power reactor control system
International Nuclear Information System (INIS)
Danupoyo, S.D.
1997-01-01
A power reactor is an important part in nuclear powered electrical plant systems. Success in controlling the power reactor will establish safety of the whole power plant systems. Until now, the power reactor has been controlled by a classical control system that was designed based on output feedback method. To meet the safety requirements that are now more restricted, the recently used power reactor control system should be modified. this paper describes a power reactor control system that is designed based on a state feedback method optimized with LQG (Linear-quadrature-gaussian) method and equipped with a state estimator. A pressurized-water type reactor has been used as the model. by using a point kinetics method with one group delayed neutrons. the result of simulation testing shows that the optimized control system can control the power reactor more effective and efficient than the classical control system
Optimization of photovoltaic power systems
Rekioua, Djamila
2012-01-01
Photovoltaic generation is one of the cleanest forms of energy conversion available. One of the advantages offered by solar energy is its potential to provide sustainable electricity in areas not served by the conventional power grid. Optimisation of Photovoltaic Power Systems details explicit modelling, control and optimisation of the most popular stand-alone applications such as pumping, power supply, and desalination. Each section is concluded by an example using the MATLAB(R) and Simulink(R) packages to help the reader understand and evaluate the performance of different photovoltaic syste
Investigations of heat-hydraulic noises in the equipment for creation of power-saving technologies
International Nuclear Information System (INIS)
Proskuryakov, K.N.
2000-01-01
The results of experimental and theoretical studies on the parameters of vibroacoustic signals, originating in the TPP and NPP thermal energy equipment, are presented. The methods for calculation and identification of the heat-hydraulic perturbation sources, intended for improving the means of early diagnostics of anomalies in the technological process, forecasting their development, increasing the maintenance work efficiency and operational safety, as well as for creating power-saving technologies in the power engineering, are developed [ru
Optimization of heat saving in buildings using unsteady heat transfer model
Directory of Open Access Journals (Sweden)
Dedinec Aleksandra
2015-01-01
Full Text Available Reducing the energy consumption growth rate is increasingly becoming one of the main challenges for ensuring sustainable development, particularly in the buildings as the largest end-use sector in many countries. Along this line, the aim of this paper is to analyse the possibilities for energy savings in the construction of new buildings and reconstruction of the existing ones developing a tool that, in terms of the available heating technologies and insulation, provides answer to the problem of optimal cost effective energy consumption. The tool is composed of an unsteady heat transfer model which is incorporated into a cost-effective energy saving optimization. The unsteady heat transfer model uses annual hourly meteorological data, chosen as typical for the last ten-year period, as well as thermo physical features of the layers of the building walls. The model is tested for the typical conditions in the city of Skopje, Macedonia. The results show that the most cost effective heating technology for the given conditions is the wood fired stove, followed by the inverter air-conditioner. The centralized district heating and the pellet fired stoves are the next options. The least cost effective option is the panel that uses electricity. In this paper, the optimal insulation thickness is presented for each type of heating technology.
Transmission tariffs based on optimal power flow
International Nuclear Information System (INIS)
Wangensteen, Ivar; Gjelsvik, Anders
1998-01-01
This report discusses transmission pricing as a means of obtaining optimal scheduling and dispatch in a power system. This optimality includes consumption as well as generation. The report concentrates on how prices can be used as signals towards operational decisions of market participants (generators, consumers). The main focus is on deregulated systems with open access to the network. The optimal power flow theory, with demand side modelling included, is briefly reviewed. It turns out that the marginal costs obtained from the optimal power flow gives the optimal transmission tariff for the particular load flow in case. There is also a correspondence between losses and optimal prices. Emphasis is on simple examples that demonstrate the connection between optimal power flow results and tariffs. Various cases, such as open access and single owner are discussed. A key result is that the location of the ''marketplace'' in the open access case does not influence the net economical result for any of the parties involved (generators, network owner, consumer). The optimal power flow is instantaneous, and in its standard form cannot deal with energy constrained systems that are coupled in time, such as hydropower systems with reservoirs. A simplified example of how the theory can be extended to such a system is discussed. An example of the influence of security constraints on prices is also given. 4 refs., 24 figs., 7 tabs
Marginal costs of water savings from cooling system retrofits: a case study for Texas power plants
Loew, Aviva; Jaramillo, Paulina; Zhai, Haibo
2016-10-01
The water demands of power plant cooling systems may strain water supply and make power generation vulnerable to water scarcity. Cooling systems range in their rates of water use, capital investment, and annual costs. Using Texas as a case study, we examined the cost of retrofitting existing coal and natural gas combined-cycle (NGCC) power plants with alternative cooling systems, either wet recirculating towers or air-cooled condensers for dry cooling. We applied a power plant assessment tool to model existing power plants in terms of their key plant attributes and site-specific meteorological conditions and then estimated operation characteristics of retrofitted plants and retrofit costs. We determined the anticipated annual reductions in water withdrawals and the cost-per-gallon of water saved by retrofits in both deterministic and probabilistic forms. The results demonstrate that replacing once-through cooling at coal-fired power plants with wet recirculating towers has the lowest cost per reduced water withdrawals, on average. The average marginal cost of water withdrawal savings for dry-cooling retrofits at coal-fired plants is approximately 0.68 cents per gallon, while the marginal recirculating retrofit cost is 0.008 cents per gallon. For NGCC plants, the average marginal costs of water withdrawal savings for dry-cooling and recirculating towers are 1.78 and 0.037 cents per gallon, respectively.
Optimal load allocation of complex ship power plants
International Nuclear Information System (INIS)
Baldi, Francesco; Ahlgren, Fredrik; Melino, Francesco; Gabrielii, Cecilia; Andersson, Karin
2016-01-01
Highlights: • The optimal operation of the prime movers of hybrid ship power plants is addressed. • Both mechanical, electric and thermal power demand are considered. • The problem is modelled as a mixed integer-nonlinear programming problem. • Up to 3% savings can be achieved with hybrid power plants. • Including the thermal power demand improves the solution by up to 4%. - Abstract: In a world with increased pressure on reducing fuel consumption and carbon dioxide emissions, the cruise industry is growing in size and impact. In this context, further effort is required for improving the energy efficiency of cruise ship energy systems. In this paper, we propose a generic method for modelling the power plant of an isolated system with mechanical, electric and thermal power demands and for the optimal load allocation of the different components that are able to fulfil the demand. The optimisation problem is presented in the form of a mixed integer linear programming (MINLP) problem, where the number of engines and/or boilers running is represented by the integer variables, while their respective load is represented by the non-integer variables. The individual components are modelled using a combination of first-principle models and polynomial regressions, thus making the system nonlinear. The proposed method is applied to the load-allocation problem of a cruise ship sailing in the Baltic Sea, and used to compare the existing power plant with a hybrid propulsion plant. The results show the benefits brought by using the proposing method, which allow estimating the performance of the hybrid system (for which the load allocation is a non-trivial problem) while also including the contribution of the heat demand. This allows showing that, based on a reference round voyage, up to 3% savings could be achieved by installing the proposed system, compared to the existing one, and that a NPV of 11 kUSD could be achieved already 5 years after the installation of the
Optimization of thermal insulation to achieve energy savings in low energy house (refurbishment)
International Nuclear Information System (INIS)
Bojić, Milorad; Miletić, Marko; Bojić, Ljubiša
2014-01-01
Highlights: • For buildings that require heating, a thickness of their thermal insulation is optimized. • The objective was to improve energy efficiency of the building. • The optimization is performed by using EnergyPlus and Hooke–Jeeves method. • The embodied energy of thermal insulation and the entire life cycle of the house are taken into account. - Abstract: Due to the current environmental situation, saving energy and reducing CO 2 emission have become the leading drive in modern research. For buildings that require heating, one of the solutions is to optimize a thickness of their thermal insulation and thus improve energy efficiency and reduce energy needs. In this paper, for a small residential house in Serbia, an optimization in the thickness of its thermal insulation layer is investigated by using EnergyPlus software and Hooke–Jeeves direct search method. The embodied energy of thermal insulation is taken into account. The optimization is done for the entire life cycle of thermal insulation. The results show the optimal thickness of thermal insulation that yields the minimum primary energy consumption
Optimal Operation of Interdependent Power Systems and Electrified Transportation Networks
Directory of Open Access Journals (Sweden)
M. Hadi Amini
2018-01-01
Full Text Available Electrified transportation and power systems are mutually coupled networks. In this paper, a novel framework is developed for interdependent power and transportation networks. Our approach constitutes solving an iterative least cost vehicle routing process, which utilizes the communication of electrified vehicles (EVs with competing charging stations, to exchange data such as electricity price, energy demand, and time of arrival. The EV routing problem is solved to minimize the total cost of travel using the Dijkstra algorithm with the input from EVs battery management system, electricity price from charging stations, powertrain component efficiencies and transportation network traffic conditions. Through the bidirectional communication of EVs with competing charging stations, EVs’ charging demand estimation is done much more accurately. Then the optimal power flow problem is solved for the power system, to find the locational marginal price at load buses where charging stations are connected. Finally, the electricity prices were communicated from the charging stations to the EVs, and the loop is closed. Locational electricity price acts as the shared parameter between the two optimization problems, i.e., optimal power flow and optimal routing problem. Electricity price depends on the power demand, which is affected by the charging of EVs. On the other hand, location of EV charging stations and their different pricing strategies might affect the routing decisions of the EVs. Our novel approach that combines the electrified transportation with power system operation, holds tremendous potential for solving electrified transportation issues and reducing energy costs. The effectiveness of the proposed approach is demonstrated using Shanghai transportation network and IEEE 9-bus test system. The results verify the cost-savings for both power system and transportation networks.
Directory of Open Access Journals (Sweden)
Odintsova Tetiana M.
2017-04-01
Full Text Available The article is aimed at studying the optimal factors of formation of the population savings as the basis for investment resources of the regional economy. A factorial (nonlinear correlative-regression analysis of the formation of savings of the population of Ukraine was completed. On its basis a forecast of the optimal structure and volumes of formation of the population incomes was carried out taking into consideration impact of fundamental factors on these incomes. Such approach provides to identify the marginal volumes of tax burden, population savings, and capital investments, directed to economic growth.
Optimal Control of Wind Power Generation
Directory of Open Access Journals (Sweden)
Pawel Pijarski
2018-03-01
Full Text Available Power system control is a complex task, which is strongly related to the number and kind of generating units as well as to the applied technologies, such as conventional coal fired power plants or wind and photovoltaic farms. Fast development of wind generation that is considered as unstable generation sets new strong requirements concerning remote control and data hubs cooperating with SCADA systems. Considering specific nature of the wind power generation, the authors analyze the problem of optimal control for wind power generation in farms located over a selected remote-controlled part of the Operator grid under advantageous wind conditions. This article presents an original stepwise method for tracing power flows that makes possible to eliminate current (power overloading of power grid branches. Its core idea is to consider the discussed problem as an optimization task.
Solar-Diesel Hybrid Power System Optimization and Experimental Validation
Jacobus, Headley Stewart
As of 2008 1.46 billion people, or 22 percent of the World's population, were without electricity. Many of these people live in remote areas where decentralized generation is the only method of electrification. Most mini-grids are powered by diesel generators, but new hybrid power systems are becoming a reliable method to incorporate renewable energy while also reducing total system cost. This thesis quantifies the measurable Operational Costs for an experimental hybrid power system in Sierra Leone. Two software programs, Hybrid2 and HOMER, are used during the system design and subsequent analysis. Experimental data from the installed system is used to validate the two programs and to quantify the savings created by each component within the hybrid system. This thesis bridges the gap between design optimization studies that frequently lack subsequent validation and experimental hybrid system performance studies.
Optimal control applications in electric power systems
Christensen, G S; Soliman, S A
1987-01-01
Significant advances in the field of optimal control have been made over the past few decades. These advances have been well documented in numerous fine publications, and have motivated a number of innovations in electric power system engineering, but they have not yet been collected in book form. Our purpose in writing this book is to provide a description of some of the applications of optimal control techniques to practical power system problems. The book is designed for advanced undergraduate courses in electric power systems, as well as graduate courses in electrical engineering, applied mathematics, and industrial engineering. It is also intended as a self-study aid for practicing personnel involved in the planning and operation of electric power systems for utilities, manufacturers, and consulting and government regulatory agencies. The book consists of seven chapters. It begins with an introductory chapter that briefly reviews the history of optimal control and its power system applications and also p...
Optimal control systems in hydro power plants
International Nuclear Information System (INIS)
Babunski, Darko L.
2012-01-01
The aim of the research done in this work is focused on obtaining the optimal models of hydro turbine including auxiliary equipment, analysis of governors for hydro power plants and analysis and design of optimal control laws that can be easily applicable in real hydro power plants. The methodology of the research and realization of the set goals consist of the following steps: scope of the models of hydro turbine, and their modification using experimental data; verification of analyzed models and comparison of advantages and disadvantages of analyzed models, with proposal of turbine model for design of control low; analysis of proportional-integral-derivative control with fixed parameters and gain scheduling and nonlinear control; analysis of dynamic characteristics of turbine model including control and comparison of parameters of simulated system with experimental data; design of optimal control of hydro power plant considering proposed cost function and verification of optimal control law with load rejection measured data. The hydro power plant models, including model of power grid are simulated in case of island ing and restoration after breakup and load rejection with consideration of real loading and unloading of hydro power plant. Finally, simulations provide optimal values of control parameters, stability boundaries and results easily applicable to real hydro power plants. (author)
Power consumption optimization strategy for wireless networks
DEFF Research Database (Denmark)
Cornean, Horia; Kumar, Sanjay; Marchetti, Nicola
2011-01-01
in order to reduce the total power consumption in a multi cellular network. We present an algorithm for power optimization under no interference and in presence of interference conditions, targeting to maximize the network capacity. The convergence of the algorithm is guaranteed if the interference...
Directory of Open Access Journals (Sweden)
Hye Yeon Kim
2016-03-01
Full Text Available This study suggests an optimization method for the life cycle cost (LCC in an economic feasibility analysis when applying energy saving techniques in the early design stage of a building. Literature and previous studies were reviewed to select appropriate optimization and LCC analysis techniques. The energy simulation (Energy Plus and computational program (MATLAB were linked to provide an automated optimization process. From the results, it is suggested that this process could outline the cost optimization model with which it is possible to minimize the LCC. To aid in understanding the model, a case study on an industrial building was performed to outline the operations of the cost optimization model including energy savings. An energy optimization model was also presented to illustrate the need for the cost optimization model.
Directory of Open Access Journals (Sweden)
Alireza Fazlali
2010-01-01
Full Text Available While energy prices continue to climb, it conservation remains the prime concern for process industries. The daily growth of energy consumption throughout the world and the real necessity of providing it, shows that optimization of energy generation and consumption units is an economical and sometimes vital case. Hence, the optimization of a petroleum refinery is aimed towards great production and an increase in quality. In this research, the atmospheric distillation unit of the Iran-Arak-Shazand petroleum refinery was subject to optimization efforts. It was performed by the means of using a simulator with the aim to earn more overhead products. In the next step the optimization results from the simulators were carried out in the real world, at the above mentioned unit. Results demonstrate that the changes in the real operating conditions increase the overhead products with desirable quality. Finally, a net economical balance between the increments of the overhead products and the energy consumption shows an energy saving in this refinery.
Optimal Load Response to Time-of-Use Power Price for Demand Side Management in Denmark
DEFF Research Database (Denmark)
Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte
2010-01-01
-of-use power price for demand side management in order to save the energy costs as much as possible. 3 typical different kinds of loads (industrial load, residential load and commercial load) in Denmark are chosen as study cases. The energy costs decrease up to 9.6% with optimal load response to time......-of-use power price for different loads. Simulation results show that the optimal load response to time-of-use power price for demand side management generates different load profiles and reduces the load peaks. This kind of load patterns may also have significant effects on the power system normal operation.......Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift their loads from high price periods to the low price periods in order to save their energy costs. This paper presents a load optimization method to time...
Variable flow controls of closed system pumps for energy savings in maritime power systems
Su, Chun-Lien; Liao, Chi-Hsiang; Chou, Tso-Chu; Chou, Ming-Hung; Guerrero, Josep M.
2016-01-01
Pumps are extensively used in maritime industries as marine vessels utilize a wide range of pumps and pumping techniques to transfer and distribute all types of air and fluids. The electrical energy consumed by the various motors accounts for about 70% of a vessel’s total power consumption, and this presents a problem in unique marine environments. Such situations are especially conducive to energy-saving strategies using variable frequency drives (VFDs) in centrifugal load service. This pape...
DEFF Research Database (Denmark)
Browning, Martin; Lusardi, Annamaria
suggested in the informal saving literature can be captured in the standard optimizing model. Particular attention is given to recent work on the precautionary motive and its implications for saving and consumption behavior. We also discuss the "behavioral" or "psychological" approach that eschews the use......In this survey, we review the recent theoretical and empirical literature on household saving and consumption. The discussion is structured around a list of motives for saving and how well the standard theory captures these motives. We show that almost all of the motives for saving that have been...
Optimization and Control of Electric Power Systems
Energy Technology Data Exchange (ETDEWEB)
Lesieutre, Bernard C. [Univ. of Wisconsin, Madison, WI (United States); Molzahn, Daniel K. [Univ. of Wisconsin, Madison, WI (United States)
2014-10-17
The analysis and optimization needs for planning and operation of the electric power system are challenging due to the scale and the form of model representations. The connected network spans the continent and the mathematical models are inherently nonlinear. Traditionally, computational limits have necessitated the use of very simplified models for grid analysis, and this has resulted in either less secure operation, or less efficient operation, or both. The research conducted in this project advances techniques for power system optimization problems that will enhance reliable and efficient operation. The results of this work appear in numerous publications and address different application problems include optimal power flow (OPF), unit commitment, demand response, reliability margins, planning, transmission expansion, as well as general tools and algorithms.
Optimization of Temperature Schedule Parameters on Heat Supply in Power-and-Heat Supply Systems
Directory of Open Access Journals (Sweden)
V. A. Sednin
2009-01-01
Full Text Available The paper considers problems concerning optimization of a temperature schedule in the district heating systems with steam-turbine thermal power stations having average initial steam parameters. It has been shown in the paper that upkeeping of an optimum network water temperature permits to increase an energy efficiency of heat supply due to additional systematic saving of fuel.
Optimization of IGCT for pulsed power
International Nuclear Information System (INIS)
Chen Fanglin; Tang Longgu; Chen Yongmin; Pan Xuejun
2014-01-01
In order to develop high-performance IGCT devices applied in pulse power, cathode finger layout is optimized, the finger structure is modified, minority carrier lifetime is properly controlled and gate triggering characteristics is improved. As a result of these measures, the IGCT turn -on di/dt is improved, current handling capability is enhanced and switching response speed is increased. The feasibility and validity of the optimization study on the IGCT is verified by simulation and experimental results. (authors)
Offshore wind energy storage concept for cost-of-rated-power savings
International Nuclear Information System (INIS)
Qin, Chao; Saunders, Gordon; Loth, Eric
2017-01-01
Highlights: •Investigated CAES + HPT system concept for offshore wind energy; •Validated cost model for offshore wind farm including CAPEX and OPEX items; •Quantified cost-of-rated-power savings associated with CAES + HPT concept; •Estimated savings of 21.6% with CAES + HPT for a sample $2.92 billion project. -- Abstract: The size and number of off-shore wind turbines over the next decade is expected to rapidly increase due to the high wind energy potential and the ability of such farms to provide utility-scale energy. In this future, inexpensive and efficient on-site wind energy storage can be critical to address short-time (hourly) mismatches between wind supply and energy demand. This study investigates a compressed air energy storage (CAES) and hydraulic power transmission (HPT) system concept. To assess cost impact, the NREL Cost and Scaling Model was modified to improve accuracy and robustness for offshore wind farms with large turbines. Special attention was paid to the support structure, installation, electrical interface and connections, land leasing, and operations and maintenance cost items as well as specific increased/reduced costs reductions associated with CAES + HPT systems. This cost model was validated and applied to a sample $2.92 billion project Virginia Offshore case It was found that adaption of CAES + HPT can lead to a substantial savings of 21.6% of this 20-year lifetime cost by dramatically reducing capital and operating cost of the generator and power transmission components. However, there are several additional variables that can impact the off-shore energy policy and planning for this new CAES + HPT concept. Furthermore, these cost-savings are only first-order estimates based on linear mass-cost relationships, and thus detailed engineering and economic analysis are recommended.
Energy-Saving Optimization of Water Supply Pumping Station Life Cycle Based on BIM Technology
Qun, Miao; Wang, Jiayuan; Liu, Chao
2017-12-01
In the urban water supply system, pump station is the main unit of energy consumption. In the background of pushing forward the informatization in China, using BIM technology in design, construction and operations of water supply pumping station, can break through the limitations of the traditional model and effectively achieve the goal of energy conservation and emissions reduction. This work researches the way to solve energy-saving optimization problems in the process of whole life cycle of water supply pumping station based on BIM technology, and put forward the feasible strategies of BIM application in order to realize the healthy and sustainable development goals by establishing the BIM model of water supply pumping station of Qingdao Guzhenkou water supply project.
Optimization of a wearable power system
Energy Technology Data Exchange (ETDEWEB)
Kovacevic, I.; Round, S. D.; Kolar, J. W.; Boulouchos, K.
2008-07-01
In this paper the optimization of wearable power system comprising of an internal combustion engine, motor/generator, inverter/rectifier, Li-battery pack, DC/DC converters, and controller is performed. The Wearable Power System must have the capability to supply an average 20 W for 4 days with peak power of 200 W and have a system weight less then 4 kg. The main objectives are to select the engine, fuel and battery type, to match the weight of fuel and the number of battery cells, to find the optimal working point of engine and minimizing the system weight. The minimization problem is defined in Matlab as a nonlinear constrained optimization task. The optimization procedure returns the optimal system design parameters: the Li-polymer battery with eight cells connected in series for a 28 V DC output voltage, the selection of gasoline/oil fuel mixture and the optimal engine working point of 12 krpm for a 4.5 cm{sup 3} 4-stroke engine. (author)
Power Consumption Optimization in Tooth Gears Processing
Kanatnikov, N.; Harlamov, G.; Kanatnikova, P.; Pashmentova, A.
2018-01-01
The paper reviews the issue of optimization of technological process of tooth gears production of the power consumption criteria. The authors dwell on the indices used for cutting process estimation by the consumed energy criteria and their applicability in the analysis of the toothed wheel production process. The inventors proposed a method for optimization of power consumptions based on the spatial modeling of cutting pattern. The article is aimed at solving the problem of effective source management in order to achieve economical and ecological effect during the mechanical processing of toothed gears. The research was supported by Russian Science Foundation (project No. 17-79-10316).
Power and performance software analysis and optimization
Kukunas, Jim
2015-01-01
Power and Performance: Software Analysis and Optimization is a guide to solving performance problems in modern Linux systems. Power-efficient chips are no help if the software those chips run on is inefficient. Starting with the necessary architectural background as a foundation, the book demonstrates the proper usage of performance analysis tools in order to pinpoint the cause of performance problems, and includes best practices for handling common performance issues those tools identify. Provides expert perspective from a key member of Intel's optimization team on how processors and memory
Hydrothermal optimal power flow using continuation method
International Nuclear Information System (INIS)
Raoofat, M.; Seifi, H.
2001-01-01
The problem of optimal economic operation of hydrothermal electric power systems is solved using powerful continuation method. While in conventional approach, fixed generation voltages are used to avoid convergence problems, in the algorithm, they are treated as variables so that better solutions can be obtained. The algorithm is tested for a typical 5-bus and 17-bus New Zealand networks. Its capabilities and promising results are assessed
A Downlink and Uplink Alignment Scheme for Power Saving in IEEE 802.16 Protocol
Directory of Open Access Journals (Sweden)
Jenhui Chen
2014-01-01
Full Text Available This study shows the problem of power saving mechanism (PSM that sleep intervals of uplink (UL connections do not synchronize with sleep intervals of downlink (DL connections. That is, the energy of a mobile station (MS is not really saved if the DL connections are in the sleep mode while the UL connections are in normal mode, and vice versa. To avoid the asynchronism of power saving (PS between UL and DL connections, we invent a mechanism of DL connections regulating UL connections, called DL and UL Alignment (DUAL scheme, to improve the energy efficiency for PS. Considering that the buffer size of MS is limited, DUAL uses the mean packet arrival rate of UL λu and a relatively safe threshold of buffer size QT as the parameters to estimate the maximum allowable waiting time to align the UL with the DL connections. To analyze the performance of DUAL, a system model of PS is proposed to evaluate the performance of DUAL under different conditions. The correctness of performance analysis of DUAL is validated by using simulation with realistic parameters. Numerical experiments show that DUAL improves the energy conservation significantly when UL traffic is greater than DL traffic.
Variable flow controls of closed system pumps for energy savings in maritime power systems
DEFF Research Database (Denmark)
Su, Chun-Lien; Liao, Chi-Hsiang; Chou, Tso-Chu
2016-01-01
and field tests of a practical auxiliary boiler feed water management system on a commercial vessel. It is proved that the proposed method can maintain constant water pressure for closed system pumps and provide an efficient way to measure energy savings and maintenance benefits. The results serve......Pumps are extensively used in maritime industries as marine vessels utilize a wide range of pumps and pumping techniques to transfer and distribute all types of air and fluids. The electrical energy consumed by the various motors accounts for about 70% of a vessel’s total power consumption......, and this presents a problem in unique marine environments. Such situations are especially conducive to energy-saving strategies using variable frequency drives (VFDs) in centrifugal load service. This paper presents the design and results of applying variable frequency constant pressure technology in closed system...
DEFF Research Database (Denmark)
Hu, Weihao; Su, Chi; Chen, Zhe
2011-01-01
Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift some of their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to an electricity price...... price is proposed. A 17-bus power system with high wind power penetrations, which resembles the Eastern Danish power system, is chosen as the study case. Simulation results show that the optimal load response to electricity prices is an effective measure to improve the small signal stability of power...... for demand side management generates different load profiles and may provide an opportunity to improve the small signal stability of power systems with high wind power penetrations. In this paper, the idea of power system small signal stability improvement by using optimal load response to the electricity...
Fuel optimization of Qinshan nuclear power plant
International Nuclear Information System (INIS)
Liao Zejun; Li Zhuoqun; Kong Deping; Xue Xincai; Wang Shiwei
2010-01-01
Based on the design practice of the fuel replacement of Qin Shan nuclear power plant, this document effectively analyzes the shortcomings of current replacement design of Qin Shan. To address these shortcomings, this document successfully implements the 300 MW fuel optimization program from fuel replacement. fuel improvement and experimentation ,and achieves great economic results. (authors)
Optimal chiller sequencing by branch and bound method for saving energy
International Nuclear Information System (INIS)
Chang, Y.-C.; Lin, F.-A.; Lin, C.H.
2005-01-01
This paper proposes a method for using the branch and bound (B and B) method to solve the optimal chiller sequencing (OCS) problem and to eliminate the deficiencies of conventional methods. The coefficient of performance (COP) of the chiller is adopted as the objective function because it is concave. The Lagrangian method determines the optimal chiller loading (OCL) in each feasible state. The potential performance of the proposed method is examined with reference to an example system. The proposed method consumes much less power than the conventional method and is very appropriate for application in air conditioning systems
Virtual Power Plant and Microgrids controller for Energy Management based on optimization techniques
Directory of Open Access Journals (Sweden)
Maher G. M. Abdolrasol
2017-06-01
Full Text Available This paper discuss virtual power plant (VPP and Microgrid controller for energy management system (EMS based on optimization techniques by using two optimization techniques namely Backtracking search algorithm (BSA and particle swarm optimization algorithm (PSO. The research proposes use of multi Microgrid in the distribution networks to aggregate the power form distribution generation and form it into single Microgrid and let these Microgrid deal directly with the central organizer called virtual power plant. VPP duties are price forecast, demand forecast, weather forecast, production forecast, shedding loads, make intelligent decision and for aggregate & optimizes the data. This huge system has been tested and simulated by using Matlab simulink. These paper shows optimizations of two methods were really significant in the results. But BSA is better than PSO to search for better parameters which could make more power saving as in the results and the discussion.
Optimal Regulation of Virtual Power Plants
Energy Technology Data Exchange (ETDEWEB)
Dall Anese, Emiliano; Guggilam, Swaroop S.; Simonetto, Andrea; Chen, Yu Christine; Dhople, Sairaj V.
2018-03-01
This paper develops a real-time algorithmic framework for aggregations of distributed energy resources (DERs) in distribution networks to provide regulation services in response to transmission-level requests. Leveraging online primal-dual-type methods for time-varying optimization problems and suitable linearizations of the nonlinear AC power-flow equations, we believe this work establishes the system-theoretic foundation to realize the vision of distribution-level virtual power plants. The optimization framework controls the output powers of dispatchable DERs such that, in aggregate, they respond to automatic-generation-control and/or regulation-services commands. This is achieved while concurrently regulating voltages within the feeder and maximizing customers' and utility's performance objectives. Convergence and tracking capabilities are analytically established under suitable modeling assumptions. Simulations are provided to validate the proposed approach.
Optimal Power Flow Control by Rotary Power Flow Controller
Directory of Open Access Journals (Sweden)
KAZEMI, A.
2011-05-01
Full Text Available This paper presents a new power flow model for rotary power flow controller (RPFC. RPFC injects a series voltage into the transmission line and provides series compensation and phase shifting simultaneously. Therefore, it is able to control the transmission line impedance and the active power flow through it. An RPFC is composed mainly of two rotary phase shifting transformers (RPST and two conventional (series and shunt transformers. Structurally, an RPST consists of two windings (stator and rotor windings. The rotor windings of the two RPSTs are connected in parallel and their stator windings are in series. The injected voltage is proportional to the vector sum of the stator voltages and so its amplitude and angle are affected by the rotor position of the two RPSTs. This paper, describes the steady state operation and single-phase equivalent circuit of the RPFC. Also in this paper, a new power flow model, based on power injection model of flexible ac transmission system (FACTS controllers, suitable for the power flow analysis is introduced. Proposed model is used to solve optimal power flow (OPF problem in IEEE standard test systems incorporating RPFC and the optimal settings and location of the RPFC is determined.
Wheeling rates evaluation using optimal power flows
International Nuclear Information System (INIS)
Muchayi, M.; El-Hawary, M. E.
1998-01-01
Wheeling is the transmission of electrical power and reactive power from a seller to a buyer through a transmission network owned by a third party. The wheeling rates are then the prices charged by the third party for the use of its network. This paper proposes and evaluates a strategy for pricing wheeling power using a pricing algorithm that in addition to the fuel cost for generation incorporates the optimal allocation of the transmission system operating cost, based on time-of-use pricing. The algorithm is implemented for the IEEE standard 14 and 30 bus system which involves solving a modified optimal power flow problem iteratively. The base of the proposed algorithm is the hourly spot price. The analysis spans a total time period of 24 hours. Unlike other algorithms that use DC models, the proposed model captures wheeling rates of both real and reactive power. Based on the evaluation, it was concluded that the model has the potential for wide application in calculating wheeling rates in a deregulated competitive power transmission environment. 9 refs., 3 tabs
A Suboptimal Power-Saving Transmission Scheme in Multiple Component Carrier Networks
Chung, Yao-Liang; Tsai, Zsehong
Power consumption due to transmissions in base stations (BSs) has been a major contributor to communication-related CO2 emissions. A power optimization model is developed in this study with respect to radio resource allocation and activation in a multiple Component Carrier (CC) environment. We formulate and solve the power-minimization problem of the BS transceivers for multiple-CC networks with carrier aggregation, while maintaining the overall system and respective users' utilities above minimum levels. The optimized power consumption based on this model can be viewed as a lower bound of that of other algorithms employed in practice. A suboptimal scheme with low computation complexity is proposed. Numerical results show that the power consumption of our scheme is much better than that of the conventional one in which all CCs are always active, if both schemes maintain the same required utilities.
Integrated Power Saving for Multiple Relays and UEs in LTE-TDD
Chun-Chuan Yang; Jeng-Yueng Chen; Yi-Ting Mai; Chen-Ming Yang
2017-01-01
In this paper, the design of integrated sleep scheduling for relay nodes and user equipments under a Donor eNB (DeNB) in the mode of Time Division Duplex (TDD) in LTE-A is presented. The idea of virtual time is proposed to deal with the discontinuous pattern of the available radio resource in TDD, and based on the estimation of the traffic load, three power saving schemes in the top-down strategy are presented. Associated mechanisms in each scheme including calculation of the virtual subframe...
DEFF Research Database (Denmark)
Zvingilaite, Erika; Balyk, Olexandr
2014-01-01
levels of heat savings, which can be implemented by reducing heat transmission losses through building elements and by installing ventilation systems with heat recovery, in different future Danish heat and power system scenarios. Today almost 50% of heat demand in Denmark is covered by district heating......The paper examines implementation of heat saving measures in buildings in 2050, under the assumption that heat and power supply comes solely from renewable resources in Denmark.Balmorel – a linear optimisation model of heat and power sectors in Denmark is used for investigating economically viable....... A further expansion of district heating network in Denmark is assessed and penetration of heat savings is analysed in this context.If all heat saving measures, included in the model, are implemented, heat demand in Danish buildings in 2050 could be reduced by around 40%. Results show that it is cost...
Heavy Traffic Feasible Hybrid Intracycle and Cyclic Sleep for Power Saving in 10G-EPON
Directory of Open Access Journals (Sweden)
Xintian Hu
2014-01-01
Full Text Available Energy consumption in optical access networks costs carriers substantial operational expense (OPEX every year and is one of contributing factors for the global warming. To reduce energy consumption in the 10-gigabit Ethernet passive optical network (10G-EPON, a hybrid intracycle and cyclic sleep mechanism is proposed in this paper. Under heavy traffic load, optical network units (ONUs can utilize short idle slots within each scheduling cycle to enter intracycle sleep without postponing data transmission. In this way, energy conservation is achieved even under heavy traffic load with quality of service (QoS guarantee. Under light traffic load, ONUs perform long cyclic sleep for several scheduling cycles. The adoption of cyclic sleep instead of intracycle sleep under light traffic load can reduce unnecessary frequent transitions between sleep and full active work caused by using intracycle sleep. Further, the Markov chain of the proposed mechanism is established. The performances of the proposed mechanism and existing approaches are analyzed quantitatively based on the chain. For the proposed mechanism, power saving ability with QoS guarantee even under heavy traffic and better power saving performance than existing approaches are verified by the quantitative analysis. Moreover, simulations validate the above conclusions based on the chain.
Combinatorial Optimization for Energy Saving in Nickel Industry Non-Newtonian Fluid Pumping System
International Nuclear Information System (INIS)
Hernández Ramírez, Gabriel; Legra Lobaina, Aristides; Columbié Navarro, Angel; Marcos Aníbal León Segovia
2017-01-01
In the present work a study of the influence of the rheological parameters of the lateritic hydromixtures with the energetic ones of the pumping systems that guarantee the productivity of nickel company 'Commander Pedro Sotto Alba' is carried out. From an experimental study and through an estimator, the rheological parameters are modeled as a function of the factors: temperature, solids content, chemical and granulometric composition. From an appropriate discretization of the model of the lateritic hydrometer pumping system and the application of a Discrete Combination Optimization Double Sequencing procedure, the operating parameters of this system were obtained, in order to guarantee a flow rate of 1600 m3 / h and one Adequate solids concentration. It is concluded that the use of a mathematical model that relates the rheological parameters of the lateritic pulp and the energy parameters of the pumping system, guarantee the metallurgical and energy efficiency in the acid leaching process with an average increase in production between 1000-1500 T Ni + Co / y and an energy saving of 30 MWh /year. (author)
Time-optimal control of reactor power
International Nuclear Information System (INIS)
Bernard, J.A.
1987-01-01
Control laws that permit adjustments in reactor power to be made in minimum time and without overshoot have been formulated and demonstrated. These control laws which are derived from the standard and alternate dynamic period equations, are closed-form expressions of general applicability. These laws were deduced by noting that if a system is subject to one or more operating constraints, then the time-optimal response is to move the system along these constraints. Given that nuclear reactors are subject to limitations on the allowed reactor period, a time-optimal control law would step the period from infinity to the minimum allowed value, hold the period at that value for the duration of the transient, and then step the period back to infinity. The change in reactor would therefore be accomplished in minimum time. The resulting control laws are superior to other forms of time-optimal control because they are general-purpose, closed-form expressions that are both mathematically tractable and readily implanted. Moreover, these laws include provisions for the use of feedback. The results of simulation studies and actual experiments on the 5 MWt MIT Research Reactor in which these time-optimal control laws were used successfully to adjust the reactor power are presented
Energy-saving modification on outdoor lighting in the nuclear power plant
International Nuclear Information System (INIS)
Yao Bo
2010-01-01
The outdoor lighting in the nuclear power plant don't automatically shut down,and cause lights to be long-light. It is proposed to install light-control switches in the electric circuit in order to achieve automatic control. The original outdoor lighting circuit uses the circuit breaker for over-current protection and short circuit fault protection, and use remote circuit breaker to manually operate the lamp on and off.Each circuit branch installs a light-control switch, and set the threshold of 100 lux for the light-control switch. When the natural illumination meet the minimum illumination requirement (> 100lux), the lights shut down the power.When natural illumination doesn't meet the lighting requirement (<100lux), the lighting automatically close.After the modification, it is resolved the outdoor lighting easily becoming a long light,and save energy. (authors)
International Nuclear Information System (INIS)
Zhu Zhang-Ming; Hao Bao-Tian; En Yun-Fei; Yang Yin-Tang; Li Yue-Jin
2011-01-01
On-chip interconnect buses consume tens of percents of dynamic power in a nanometer scale integrated circuit and they will consume more power with the rapid scaling down of technology size and continuously rising clock frequency, therefore it is meaningful to lower the interconnecting bus power in design. In this paper, a simple yet accurate interconnect parasitic capacitance model is presented first and then, based on this model, a novel interconnecting bus optimization method is proposed. Wire spacing is a process for spacing wires for minimum dynamic power, while wire ordering is a process that searches for wire orders that maximally enhance it. The method, i.e., combining wire spacing with wire ordering, focuses on bus dynamic power optimization with a consideration of bus performance requirements. The optimization method is verified based on various nanometer technology parameters, showing that with 50% slack of routing space, 25.71% and 32.65% of power can be saved on average by the proposed optimization method for a global bus and an intermediate bus, respectively, under a 65-nm technology node, compared with 21.78% and 27.68% of power saved on average by uniform spacing technology. The proposed method is especially suitable for computer-aided design of nanometer scale on-chip buses. (interdisciplinary physics and related areas of science and technology)
Energy Technology Data Exchange (ETDEWEB)
Ziegler, Manfred [RWE Power International RE GmbH, Koeln (Germany). Gewinnungs- und Foerdertechnik
2009-11-15
Influencing horizontal resistance to motion has the greatest leverage effect in terms of reducing the power requirements of belt conveyors. The selection of a suitable conveyor belt with optimized running resistance enables substantial cost savings, both with regard to current energy consumption and with regard to the drive power to be installed. Measurements carried out on standard conveyor belts used by RWE Power show differences of up to 30 % in the principal resistance. A method to reliably predict the energy properties of a conveyor belt by means of small specimens was developed. In addition, the requirements to be met in terms of mechanical endurance of a belt depending on conveyor configuration, which set limits to the development of energy-saving belts suitable for operation, will be outlined. To resolve this conflict of aims, conveyor engineers are given concrete tips on the design of belt conveyor systems. (orig.)
Non-take-up of Tax-favored Savings Plans : Are Household Portfolios Optimal?
Alessie, R.J.M.; Hochgürtel, S.; van Soest, A.H.O.
2001-01-01
Since the early nineties, the Dutch tax system allows for a tax-favored form of risk free savings through employer-sponsored savings plans (ESSPs).Under some conditions and up to a certain amount, the contributions to this plan are tax-deductible, and the returns as well as the withdrawals are
DEFF Research Database (Denmark)
Klinge Jacobsen, Henrik; Baldini, Mattia
the costs are incurred and savings (difference in discount rates both private and social) • The issue of marginal investment in a case of replacement anyway or a full investment in the energy saving technology • Implementation costs (and probability of investment) differs across sectors • Cost saving...... with constructing and applying the cost curves in modelling: • Cost curves do not have the same cost interpretation across economic subsectors and end-use technologies (investment cost for equipment varies – including/excluding installation – adaptation costs – indirect production costs) • The time issue of when...... options are not additive - meaning that marginal energy savings from one option depends on what other options implemented We address the importance of these issues and illustrate with Danish cases how large the difference in savings cost curves can be if different methodologies are used. For example...
Energy Technology Data Exchange (ETDEWEB)
Wilken, Christoph; Son, Frank van [WABCO, Hannover (Germany)
2009-07-01
Fuel prices, vehicles' total cost of ownership, CO2 reductions by further environmental regulations become more and more a major driver for the development of energy efficient products, operating in a commercial vehicle. By example for the delivery and management of compressed air in a commercial vehicle, a compressor and an electronic controlled air processing unit (WABCO E-APU) are able to contribute a significant impact on energy savings, once through the way of creating compressed air and secondly by intelligent control of the compressor and the pressure levels, through an E-APU. Starting with the generation of compressed air, WABCO offers different systems with varying influence on the vehicle's fuel consumption. Today's conventional compressor systems in Europe are mostly equipped with WABCO PR (Power Reduction) System, reducing the energy consumption of the compressor in its idle phases. Further reduction of energy consumption during compressor idling is given by the usage of clutch principles, where the energy consumption during theses idle phases is greatly reduced. Next step to reduce also the energy consumption during compressor on-load phases, was the development of the WABCO two stage compressors which are using, compared to conventional one stage compressors, a more energy efficient way of compressing the needed air. Most effective intelligent air management systems include a compressor, associated with an electronic controlled air processing system (WABCO E-APU). By performing intelligent regeneration and keeping the compressor line plus cartridge pressurized during compressor idling, it is possible to utilize shortest overrun phases for pumping compressed air into the system and herewith generate additional energy savings. In near future, more and more hybrid vehicles with high voltage systems will enter the market, the WABCO electronic driven compressor (e-comp) stands for the best choice. It runs at different speeds, independent of
Problems of the power plant shield optimization
International Nuclear Information System (INIS)
Abagyan, A.A.; Dubinin, A.A.; Zhuravlev, V.I.; Kurachenko, Yu.A.; Petrov, Eh.E.
1981-01-01
General approaches to the solution of problems on the nuclear power plant radiation shield optimization are considered. The requirements to the shield parameters are formulated in a form of restrictions on a number of functionals, determined by the solution of γ quantum and neutron transport equations or dimensional and weight characteristics of shield components. Functional determined by weight-dimensional parameters (shield cost, mass and thickness) and functionals, determined by radiation fields (equivalent dose rate, produced by neutrons and γ quanta, activation functional, radiation functional, heat flux, integral heat flux in a particular part of the shield volume, total energy flux through a particular shield surface are considered. The following methods of numerical solution of simplified optimization problems are discussed: semiempirical methods using radiation transport physical leaks, numerical solution of approximate transport equations, numerical solution of transport equations for the simplest configurations making possible to decrease essentially a number of variables in the problem. The conclusion is drawn that the attained level of investigations on the problem of nuclear power plant shield optimization gives the possibility to pass on at present to the solution of problems with a more detailed account of the real shield operating conditions (shield temperature field account, its strength and other characteristics) [ru
Study on key technologies of optimization of big data for thermal power plant performance
Mao, Mingyang; Xiao, Hong
2018-06-01
Thermal power generation accounts for 70% of China's power generation, the pollutants accounted for 40% of the same kind of emissions, thermal power efficiency optimization needs to monitor and understand the whole process of coal combustion and pollutant migration, power system performance data show explosive growth trend, The purpose is to study the integration of numerical simulation of big data technology, the development of thermal power plant efficiency data optimization platform and nitrogen oxide emission reduction system for the thermal power plant to improve efficiency, energy saving and emission reduction to provide reliable technical support. The method is big data technology represented by "multi-source heterogeneous data integration", "large data distributed storage" and "high-performance real-time and off-line computing", can greatly enhance the energy consumption capacity of thermal power plants and the level of intelligent decision-making, and then use the data mining algorithm to establish the boiler combustion mathematical model, mining power plant boiler efficiency data, combined with numerical simulation technology to find the boiler combustion and pollutant generation rules and combustion parameters of boiler combustion and pollutant generation Influence. The result is to optimize the boiler combustion parameters, which can achieve energy saving.
Class H power amplifier for power saving in fluxgate current transducers
Velasco Quesada, Guillermo; Román Lumbreras, Manuel; Pérez Delgado, Raul; Conesa Roca, Alfons
2016-01-01
This paper presents a new improvement in the design of a fluxgate-based current transducer in order to reduce the power consumption of control electronics. The proposed improvement involves the replacement of the output linear amplifier of the transducer by a class H amplifier. The output amplifier is devoted to the magnetic flux compensation and generates the transducer output current, which is proportional to the current to be measured. In this way, it is possible to reduce significantly th...
Fuel and power resources based on energy-saving technologies and technical means in agriculture
Directory of Open Access Journals (Sweden)
A. V. Tikhomirov
2015-01-01
Full Text Available The state and efficiency of the use of the energy supply systems in agriculture were analyzed. It is demonstrated that grids and power equipment deterioration exceeds 30 percent, and fuel volume-efficiency ratio is not more than 35 percent in this sector. A considerable part of the country territory (mainly the northern one does not have centralized power supply. Decentralized cogeneration systems with extensive use of renewable energy sources and local energy recourses are highly efficient for this part. A necessity of development of methodology and recommendations for the selection of efficient systems and technical means of power supply to agricultural enterprises was substantiated with due consideration of their location, load intensity and distance from centralized grids. The most important indication of energy efficiency is energy intensity of products and energy inputs share in the production cost. Reserves for energy saving including the development of energy-efficient technologies and technical means, some of which have already been developed (equipment for lighting, microclimate, primary treatment and storage of products, disinfection or are at the completion stage were presented. Their implementation in agricultural production will make it possible to raise considerably the efficiency of the use of fuel and power resources and to reduce energy consumption. The conditions in which the use of decentralized power supply systems is most efficient were educed. The characteristics of related equipment and the specifics of its use at agricultural enterprises are described. The proposal and priority actions for the development and upgrading of power supply systems for agriculture have been elaborated.
Optimized efficiency of all-electric ships by dc hybrid power systems
Zahedi, Bijan; Norum, Lars E.; Ludvigsen, Kristine B.
2014-06-01
Hybrid power systems with dc distribution are being considered for commercial marine vessels to comply with new stringent environmental regulations, and to achieve higher fuel economy. In this paper, detailed efficiency analysis of a shipboard dc hybrid power system is carried out. An optimization algorithm is proposed to minimize fuel consumption under various loading conditions. The studied system includes diesel engines, synchronous generator-rectifier units, a full-bridge bidirectional converter, and a Li-Ion battery bank as energy storage. In order to evaluate potential fuel saving provided by such a system, an online optimization strategy for fuel consumption is implemented. An Offshore Support Vessel (OSV) is simulated over different operating modes using the online control strategy. The resulted consumed fuel in the simulation is compared to that of a conventional ac power system, and also a dc power system without energy storage. The results show that while the dc system without energy storage provides noticeable fuel saving compared to the conventional ac system, optimal utilization of the energy storage in the dc system results in twice as much fuel saving.
Nassiri, Nader; Sheibani, Kourosh; Azimi, Abbas; Khosravi, Farinaz Mahmoodi; Heravian, Javad; Yekta, Abasali; Moghaddam, Hadi Ostadi; Nassiri, Saman; Yasseri, Mehdi; Nassiri, Nariman
2015-10-01
To compare refractive outcomes, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after photorefractive keratectomy for correction of moderate myopia with two methods: tissue saving versus wavefront optimized. In this prospective, comparative study, 152 eyes (80 patients) with moderate myopia with and without astigmatism were randomly divided into two groups: the tissue-saving group (Technolas 217z Zyoptix laser; Bausch & Lomb, Rochester, NY) (76 eyes of 39 patients) or the wavefront-optimized group (WaveLight Allegretto Wave Eye-Q laser; Alcon Laboratories, Inc., Fort Worth, TX) (76 eyes of 41 patients). Preoperative and 3-month postoperative refractive outcomes, contrast sensitivity, HOAs, and patient satisfaction were compared between the two groups. The mean spherical equivalent was -4.50 ± 1.02 diopters. No statistically significant differences were detected between the groups in terms of uncorrected and corrected distance visual acuity and spherical equivalent preoperatively and 3 months postoperatively. No statistically significant differences were seen in the amount of preoperative to postoperative contrast sensitivity changes between the two groups in photopic and mesopic conditions. HOAs and Q factor increased in both groups postoperatively (P = .001), with the tissue-saving method causing more increases in HOAs (P = .007) and Q factor (P = .039). Patient satisfaction was comparable between both groups. Both platforms were effective in correcting moderate myopia with or without astigmatism. No difference in refractive outcome, contrast sensitivity changes, and patient satisfaction between the groups was observed. Postoperatively, the tissue-saving method caused a higher increase in HOAs and Q factor compared to the wavefront-optimized method, which could be due to larger optical zone sizes in the tissue-saving group. Copyright 2015, SLACK Incorporated.
Construction and assembling optimization of power equipment
Directory of Open Access Journals (Sweden)
Marius Groza
2005-10-01
Full Text Available The main purpose of this paper is to elaborate a calculation program in Pascal language, using Delphi environment. This calculation program is designed to solve the power engineering optimization problems using the critical path method. For illustrating the use of the algorithm and the calculation program we propose an application from power engineering: a 400 kV electrical overhead line section realization. This paper is structured in 4 parts. In the first part of the paper we present the application as a problem of critic path. In the second part of the paper, we determine the critic path in a program graph and time reserves. In the third part of the paper we present a representative numerical application. In the fourth part of the paper it is described the calculation program.
Pipe support optimization in nuclear power plants
International Nuclear Information System (INIS)
Cleveland, A.B.; Kalyanam, N.
1984-01-01
A typical 1000 MWe nuclear power plant consists of 80,000 to 100,000 feet of piping which must be designed to withstand earthquake shock. For the required ground motion, seismic response spectra are developed for safety-related structures. These curves are used in the dynamic analysis of piping systems with pipe-stress analysis computer codes. To satisfy applicable Code requirements, the piping systems also require analysis for weight, thermal and possibly other lasting conditions. Bechtel Power Corporation has developed a design program called SLAM (Support Location Algorithm) for optimizing pipe support locations and types (rigid, spring, snubber, axial, lateral, etc.) while satisfying userspecified parameters such as locations, load combinations, stress and load allowables, pipe displacement and cost. This paper describes SLAM, its features, applications and benefits
DEFF Research Database (Denmark)
Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte
2010-01-01
Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to a real-time electricity price...... and may represent the future of electricity markets in some ways, is chosen as the studied power system in this paper. A distribution system where wind power capacity is 126% of maximum loads is chosen as the study case. This paper presents a nonlinear load optimization method to real-time power price...... for demand side management in order to save the energy costs as much as possible. Simulation results show that the optimal load response to a real-time electricity price has some good impacts on power system constraints in a distribution system with high wind power penetrations....
Design of sensor energy-saving controller for photovoltaic power generation%光伏发电中的传感器节能控制器设计
Institute of Scientific and Technical Information of China (English)
云彩霞; 李丽芬; 蔡小庆; 刘晨
2017-01-01
传感器储能性能较弱，导致设计出的光伏发电中的传感器节能控制器网络延迟较长、节能效果不理想。因而，设计一种新型光伏发电中的传感器节能控制器，其对供电电路、无线通信芯片和太阳光传感器芯片进行重点设计。nRF905无线通信芯片对控制器中各设备、电路、元件之间的数据通信进行监控，保障节能效果、缩短网络延迟。供电电路为控制器的节能工作供应电能、优化太阳光光强的能量转化。优化后的太阳光能量，将通过太阳光传感器中的TSL2678芯片太阳光进行参数提取和分析，输出太阳能最佳采集方位和该方位的太阳光光强，实现光伏发电的最优节能。控制器软件设计部分给出了控制器的节能控制流程。分析实验结果可知，所设计的控制器具有网络延迟短、节能效果好的特点。%Since the sensor energy⁃saving controller for the photovoltaic power generation has long network latency and un⁃satisfied energy⁃saving effect due to the poor energy storage performance of the sensor,a new sensor energy⁃saving controller for the photovoltaic power generation was designed,and its power supply circuit,wireless communication chip and solar sensor chip were designed emphatically. The wireless communication chip NRF905 is used to monitor the data communication among each device,circuit and component in the controller to ensure the energy⁃saving effect and shorten the network latency. The power supply circuit supplies the electric energy for the energy⁃saving work of the controller,and optimizes the energy conversion of so⁃lar light. The parameters of the optimized solar light energy are extracted and analyzed through the chip TSL2678 in the solar light sensor,which outputs the optimal acquisition orientation of the solar energy and its intensity to realize the optimal energy saving of the photovoltaic power generation. The energy⁃saving
PMGA and its application in area and power optimization for ternary FPRM circuit
International Nuclear Information System (INIS)
Wang Pengjun; Li Kangping; Zhang Huihong
2016-01-01
Based on the research of population migration algorithms (PMAs), a population migration genetic algorithm (PMGA) is proposed, combining a PMA with a genetic algorithm. A scheme of area and power optimization for a ternary FPRM circuit is proposed by using the PMGA. Firstly, according to the ternary FPRM logic function expression, area and power estimation models are established. Secondly, the PMGA is used to search for the best area and power polarity. Finally, 10 MCNC Benchmark circuits are used to verify the effectiveness of the proposed method. The results show that the ternary FPRM circuits optimized by the PMGA saved 13.33% area and 20.00% power on average than the corresponding FPRM circuits optimized by a whole annealing genetic algorithm. (paper)
Power and energy saving in buildings by distributed generation based on gas-engine systems
Energy Technology Data Exchange (ETDEWEB)
Arghandeh, R.; Amidpour, M.; Ghaffari, A. [Khaje Nasir Toosi Univ. of Technology, Tehran (Iran, Islamic Republic of). Joint Program of Energy Systems Engineering; Manchester Univ., Manchester (United Kingdom)
2008-07-01
Buildings consume high amounts of energy and produce high amounts of greenhouse gas (GHG) emissions. This paper discussed the use of gas cogeneration distributed generation (DG) technologies as a means of reducing energy consumption from buildings as well as energy losses from transmission lines in Iran. Energy sources and power generation systems were reviewed, and the economical benefits and energy savings resulting from the use of cogeneration systems were outlined. Actual rates of electricity consumption for Iran were estimated. Building power consumption was divided into the following 6 major sections: (1) lighting, (2) home appliances, (3) restaurant and cooking devices, (4) sports facilities, (5) utilities, and (6) electronics. Energy consumption criteria (ECC) and daily consumption charts (DCC) were used to plan and design the cogeneration systems. Energy balances, capital costs, and investment rates of return (IRR) were then calculated for 2 scenarios for a sample building. Results of the study showed that gas engine combined heat and power (CHP) DG systems are a reliable and economic technology for reducing energy consumption in buildings. The IRR of the CHP DG system for the sample building was achieved in 1 year. 13 refs., 10 tabs., 11 figs.
A Novel Power-Saving Transmission Scheme for Multiple-Component-Carrier Cellular Systems
Directory of Open Access Journals (Sweden)
Yao-Liang Chung
2016-04-01
Full Text Available As mobile data traffic levels have increased exponentially, resulting in rising energy costs in recent years, the demand for and development of green communication technologies has resulted in various energy-saving designs for cellular systems. At the same time, recent technological advances have allowed multiple component carriers (CCs to be simultaneously utilized in a base station (BS, a development that has made the energy consumption of BSs a matter of increasing concern. To help address this concern, herein we propose a novel scheme aimed at efficiently minimizing the power consumption of BS transceivers during transmission, while still ensuring good service quality and fairness for users. Specifically, the scheme utilizes the dynamic activation/deactivation of CCs during data transmission to increase power usage efficiency. To test its effectiveness, the proposed scheme was applied to a model consisting of a BS with orthogonal frequency division multiple access-based CCs in a downlink transmission environment. The results indicated that, given periods of relatively light traffic loads, the total power consumption of the proposed scheme is significantly lower than that of schemes in which all the CCs of a BS are constantly activated, suggesting the scheme’s potential for reducing both energy costs and carbon dioxide emissions.
International Nuclear Information System (INIS)
Cheng, Chuntian; Li, Shushan; Li, Gang
2014-01-01
The energy-saving generation dispatch (ESGD) policy released by Chinese Government in 2007 is a new code for optimally dispatching electric power generation portfolio in the country with the dual objectives of improving energy efficiency and reducing environmental pollution. The ESGD is substantially different from the competitive market in the developed economies, the traditional economic dispatching or the rational dispatching principle implemented in China prior to the new policy. This paper develops a hybrid method that integrates the extended priority list (EPL), the equal incremental principle (EIP) and a heuristic method to optimize daily generation schedules under ESGD. The EPL is presented to search desirable units set that satisfies the complicated duration period requirements based on thermal unit generation priority list. The EIP is developed to allocate load among the committed units within the combined set. A heuristic method is proposed to deal with inequality constraints, which usually result in difficulty for power allocation, and used to improve these results. The algorithm has been embedded into a newly developed decision support system that is currently being used by operators of the Guizhou Province Power Grid to make day-ahead quarter-hourly generation schedules. - Highlights: • Electric power industry is one of key and important fields for energy conservation and emission reduction in China. • The energy-saving generation dispatch policy was released by Chinese government in 2007. • A Hybrid algorithm for energy-saving generation dispatch scheduling of thermal power system is presented. • The algorithm has been embedded into a newly developed decision support system
Multiobjective Optimization Model for Wind Power Allocation
Directory of Open Access Journals (Sweden)
Juan Alemany
2017-01-01
Full Text Available There is an increasing need for the injection to the grid of renewable energy; therefore, to evaluate the optimal location of new renewable generation is an important task. The primary purpose of this work is to develop a multiobjective optimization model that permits finding multiple trade-off solutions for the location of new wind power resources. It is based on the augmented ε-constrained methodology. Two competitive objectives are considered: maximization of preexisting energy injection and maximization of new wind energy injection, both embedded, in the maximization of load supply. The results show that the location of new renewable generation units affects considerably the transmission network flows, the load supply, and the preexisting energy injection. Moreover, there are diverse opportunities to benefit the preexisting generation, contrarily to the expected effect where renewable generation displaces conventional power. The proposed methodology produces a diverse range of equivalent solutions, expanding and enriching the horizon of options and giving flexibility to the decision-making process.
Stochastic maintenance optimization at Candu power plants
International Nuclear Information System (INIS)
Doyle, E.K.; Duchesne, T.; Lee, C.G.; Cho, D.I.
2004-01-01
The use of various innovative maintenance optimization techniques at Bruce has lead to cost effective preventive maintenance applications for complex systems as previously reported at ICONE 6 in New Orleans (1996). Further refinement of the station maintenance strategy was evaluated via the applicability of statistical analysis of historical failure data. The viability of stochastic methods in Candu maintenance was illustrated at ICONE 10 in Washington DC (2002). The next phase consists of investigating the validity of using subjective elicitation techniques to obtain component lifetime distributions. This technique provides access to the elusive failure statistics, the lack of which is often referred to in the literature as the principal impediment preventing the use of stochastic methods in large industry. At the same time the technique allows very valuable information to be captured from the fast retiring 'baby boom generation'. Initial indications have been quite positive. The current reality of global competition necessitates the pursuit of all financial optimizers. The next construction phase in the power generation industry will soon begin on a worldwide basis. With the relatively high initial capital cost of new nuclear generation all possible avenues of financial optimization must be evaluated and implemented. (authors)
Real And Reactive Power Saving In Three Phase Induction Machine Using Star-Delta Switching Schemes
Directory of Open Access Journals (Sweden)
Ramesh Daravath
2017-04-01
Full Text Available Induction machines are the most commonly used industrial drives for variety of applications. It has been estimated that induction motors consumes approximately 50 of all the electric energy generated. Further in the area of renewable energy sources such as wind or bio-mass energy induction machines have been found suitable for functioning as generators. In this context it may be mentioned that a star-delta switching is common for the starting of three-phase induction motor. Now it is proposed to use this star-delta switching for energy conservation of induction machines i.e. at times of reduced loads the machine switched back to star connection. Using a three-phase 400 V 50 Hz 4-pole induction machine it has been demonstrated that the star-delta switching of stator winding of three-phase induction machine motor generator operations reconnected in star at suitable reduced loads with a switching arrangement can result in improved efficiency and power factor as compared to a fixed delta or star connection. The predetermined values along with the experimental results have also been presented in this report. A simulation program has been developed for the predetermination of performance of the three-phase induction machine using exact equivalent circuit. A case study on a 250 kW 400 V 4-pole three-phase induction machine operated with different load cycles reveals the significant real and reactive power savings that could be obtained in the present proposal.
Li, Jin; Qiu, Zhiling; Hu, Leilei
2018-04-01
The inverter-based regenerative braking power utilization devices can re-utilize the regenerative energy, thus reduce the energy consumption of urban rail transit. In this paper the power absorption principle of the inverter-based device is introduced, then the key influencing factors of energy saving performance are analyzed based on the absorption model. The field operation data verified that the control DC voltage plays an important role and lower control DC voltage yields more energy saving. Also, the one year energy saving performance data of an inverter-based re-utilization device located in NanJing S8 line is provided, and more than 1.2 million kWh energy is recovered in the one year operation.
Analysis of Energy Saving Potential and Optimization of Thermally Broken Fiberglass Window Frames
DEFF Research Database (Denmark)
Zajas, Jan Jakub; Heiselberg, Per
2011-01-01
This paper elaborates on the energy saving potential and development process of fiberglass window frames, with intention for application in cold climates. A method is presented, where different means of improving thermal performance of a window frame are evaluated. Firstly, very simple geometries...
Energy Technology Data Exchange (ETDEWEB)
2003-03-01
In 2001, the Visteon automotive glass plant in Nashville, Tennessee renovated its millwater pumping system. This improvement saved the plant $280,000 annually in energy and operating costs, reduced annual energy consumption by 3.2 million kilowatt-hours, reduced water consumption, improved system performance, and reduced use of water treatment chemicals.
High performance magnet power supply optimization
International Nuclear Information System (INIS)
Jackson, L.T.
1988-01-01
The power supply system for the joint LBL--SLAC proposed accelerator PEP provides the opportunity to take a fresh look at the current techniques employed for controlling large amounts of dc power and the possibility of using a new one. A basic requirement of +- 100 ppM regulation is placed on the guide field of the bending magnets and quadrupoles placed around the 2200 meter circumference of the accelerator. The optimization questions to be answered by this paper are threefold: Can a firing circuit be designed to reduce the combined effects of the harmonics and line voltage combined effects of the harmonics and line voltage unbalance to less than 100 ppM in the magnet field. Given the ambiguity of the previous statement, is the addition of a transistor bank to a nominal SCR controlled system the way to go or should one opt for an SCR chopper system running at 1 KHz where multiple supplies are fed from one large dc bus and the cost--performance evaluation of the three possible systems
Solution of optimal power flow using evolutionary-based algorithms
African Journals Online (AJOL)
It aims to estimate the optimal settings of real generator output power, bus voltage, ...... Lansey, K. E., 2003, Optimization of water distribution network design using ... Pandit, M., 2016, Economic load dispatch of wind-solar-thermal system using ...
Optimal configuration of power grid sources based on optimal particle swarm algorithm
Wen, Yuanhua
2018-04-01
In order to optimize the distribution problem of power grid sources, an optimized particle swarm optimization algorithm is proposed. First, the concept of multi-objective optimization and the Pareto solution set are enumerated. Then, the performance of the classical genetic algorithm, the classical particle swarm optimization algorithm and the improved particle swarm optimization algorithm are analyzed. The three algorithms are simulated respectively. Compared with the test results of each algorithm, the superiority of the algorithm in convergence and optimization performance is proved, which lays the foundation for subsequent micro-grid power optimization configuration solution.
Energy Technology Data Exchange (ETDEWEB)
Anon.
2010-09-15
The total view of a building is supposed to display representative impression. Spectacular architecture ensures public notice. On the other hand it is necessary to take care of the needs of the people using the specific building, including indoor climate quality. The social requirement concerning environmental protection and energy saving is of high relevance. The realization of these requirements is performed using natural venting, dynamic insulation and daylight management based on an intelligent control of windows and sun screens.
Energy Technology Data Exchange (ETDEWEB)
Wang, Dongtao
2011-09-23
High pressure die casting is an intrinsically efficient net shape process and improvements in energy efficiency are strongly dependent on design and process improvements that reduce scrap rates so that more of the total consumed energy goes into acceptable, usable castings. Computer simulation has become widely used within the industry but use is not universal. Further, many key design decisions must be made before the simulation can be run and expense in terms of money and time often limits the number of decision iterations that can be explored. This work continues several years of work creating simple, very fast, design tools that can assist with the early stage design decisions so that the benefits of simulation can be maximized and, more importantly, so that the chances of first shot success are maximized. First shot success and better running processes contributes to less scrap and significantly better energy utilization by the process. This new technology was predicted to result in an average energy savings of 1.83 trillion BTUs/year over a 10 year period. Current (2011) annual energy saving estimates over a ten year period, based on commercial introduction in 2012, a market penetration of 30% by 2015 is 1.89 trillion BTUs/year by 2022. Along with these energy savings, reduction of scrap and improvement in yield will result in a reduction of the environmental emissions associated with the melting and pouring of the metal which will be saved as a result of this technology. The average annual estimate of CO2 reduction per year through 2022 is 0.037 Million Metric Tons of Carbon Equivalent (MM TCE).
Energy Technology Data Exchange (ETDEWEB)
NONE
2011-07-01
The contribution under consideration is a guide for private households for an economically efficient conservation of electricity without renunciation of comfort. At first, reasons for saving electricity are presented. The approach to reduce power consumption consists of an inventory of electricity consumers, establishment of measures to save electricity as well as a selection of suitable measures. Tables are presented for the determination of the power consumption and costs for electricity in the actual and target state as well as for the determination of the economic efficiency.
Energy Technology Data Exchange (ETDEWEB)
Yee, S.; Milby, M.; Baker, J.
2014-06-01
Expanding on previous research by PARR, this study compares measure packages installed during 800 Illinois Home Performance with ENERGY STAR(R) (IHP) residential retrofits to those recommended as cost-optimal by Building Energy Optimization (BEopt) modeling software. In previous research, cost-optimal measure packages were identified for fifteen Chicagoland single family housing archetypes, called housing groups. In the present study, 800 IHP homes are first matched to one of these fifteen housing groups, and then the average measures being installed in each housing group are modeled using BEopt to estimate energy savings. For most housing groups, the differences between recommended and installed measure packages is substantial. By comparing actual IHP retrofit measures to BEopt-recommended cost-optimal measures, missed savings opportunities are identified in some housing groups; also, valuable information is obtained regarding housing groups where IHP achieves greater savings than BEopt-modeled, cost-optimal recommendations. Additionally, a measure-level sensitivity analysis conducted for one housing group reveals which measures may be contributing the most to gas and electric savings. Overall, the study finds not only that for some housing groups, the average IHP retrofit results in more energy savings than would result from cost-optimal, BEopt recommended measure packages, but also that linking home categorization to standardized retrofit measure packages provides an opportunity to streamline the process for single family home energy retrofits and maximize both energy savings and cost-effectiveness.
Energy Technology Data Exchange (ETDEWEB)
Yee, S. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States); Milby, M. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States); Baker, J. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States)
2014-06-01
Expanding on previous research by PARR, this study compares measure packages installed during 800 Illinois Home Performance with ENERGY STAR® (IHP) residential retrofits to those recommended as cost-optimal by Building Energy Optimization (BEopt) modeling software. In previous research, cost-optimal measure packages were identified for 15 Chicagoland single family housing archetypes. In the present study, 800 IHP homes are first matched to one of these 15 housing groups, and then the average measures being installed in each housing group are modeled using BEopt to estimate energy savings. For most housing groups, the differences between recommended and installed measure packages is substantial. By comparing actual IHP retrofit measures to BEopt-recommended cost-optimal measures, missed savings opportunities are identified in some housing groups; also, valuable information is obtained regarding housing groups where IHP achieves greater savings than BEopt-modeled, cost-optimal recommendations. Additionally, a measure-level sensitivity analysis conducted for one housing group reveals which measures may be contributing the most to gas and electric savings. Overall, the study finds not only that for some housing groups, the average IHP retrofit results in more energy savings than would result from cost-optimal, BEopt recommended measure packages, but also that linking home categorization to standardized retrofit measure packages provides an opportunity to streamline the process for single family home energy retrofits and maximize both energy savings and cost effectiveness.
optimal location of distributed generation on the nigerian power ...
African Journals Online (AJOL)
user
optimal sizing and placement of DG in the Nigerian power network for active power loss minimization. The ..... costs, resulting to low or over voltage in the network contrary to the desired ... Through Capabilities of a Wind Farm” Paper ID 99,.
Optimal Self-Tuning PID Controller Based on Low Power Consumption for a Server Fan Cooling System.
Lee, Chengming; Chen, Rongshun
2015-05-20
Recently, saving the cooling power in servers by controlling the fan speed has attracted considerable attention because of the increasing demand for high-density servers. This paper presents an optimal self-tuning proportional-integral-derivative (PID) controller, combining a PID neural network (PIDNN) with fan-power-based optimization in the transient-state temperature response in the time domain, for a server fan cooling system. Because the thermal model of the cooling system is nonlinear and complex, a server mockup system simulating a 1U rack server was constructed and a fan power model was created using a third-order nonlinear curve fit to determine the cooling power consumption by the fan speed control. PIDNN with a time domain criterion is used to tune all online and optimized PID gains. The proposed controller was validated through experiments of step response when the server operated from the low to high power state. The results show that up to 14% of a server's fan cooling power can be saved if the fan control permits a slight temperature response overshoot in the electronic components, which may provide a time-saving strategy for tuning the PID controller to control the server fan speed during low fan power consumption.
Optimal Self-Tuning PID Controller Based on Low Power Consumption for a Server Fan Cooling System
Directory of Open Access Journals (Sweden)
Chengming Lee
2015-05-01
Full Text Available Recently, saving the cooling power in servers by controlling the fan speed has attracted considerable attention because of the increasing demand for high-density servers. This paper presents an optimal self-tuning proportional-integral-derivative (PID controller, combining a PID neural network (PIDNN with fan-power-based optimization in the transient-state temperature response in the time domain, for a server fan cooling system. Because the thermal model of the cooling system is nonlinear and complex, a server mockup system simulating a 1U rack server was constructed and a fan power model was created using a third-order nonlinear curve fit to determine the cooling power consumption by the fan speed control. PIDNN with a time domain criterion is used to tune all online and optimized PID gains. The proposed controller was validated through experiments of step response when the server operated from the low to high power state. The results show that up to 14% of a server’s fan cooling power can be saved if the fan control permits a slight temperature response overshoot in the electronic components, which may provide a time-saving strategy for tuning the PID controller to control the server fan speed during low fan power consumption.
An optimal FFT-based anisotropic power spectrum estimator
Energy Technology Data Exchange (ETDEWEB)
Hand, Nick; Seljak, Uroš [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Li, Yin; Slepian, Zachary, E-mail: nhand@berkeley.edu, E-mail: yin.li@berkeley.edu, E-mail: zslepian@lbl.gov, E-mail: useljak@berkeley.edu [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
2017-07-01
Measurements of line-of-sight dependent clustering via the galaxy power spectrum's multipole moments constitute a powerful tool for testing theoretical models in large-scale structure. Recent work shows that this measurement, including a moving line-of-sight, can be accelerated using Fast Fourier Transforms (FFTs) by decomposing the Legendre polynomials into products of Cartesian vectors. Here, we present a faster, optimal means of using FFTs for this measurement. We avoid redundancy present in the Cartesian decomposition by using a spherical harmonic decomposition of the Legendre polynomials. With this method, a given multipole of order ℓ requires only 2ℓ+1 FFTs rather than the (ℓ+1)(ℓ+2)/2 FFTs of the Cartesian approach. For the hexadecapole (ℓ = 4), this translates to 40% fewer FFTs, with increased savings for higher ℓ. The reduction in wall-clock time enables the calculation of finely-binned wedges in P ( k ,μ), obtained by computing multipoles up to a large ℓ{sub max} and combining them. This transformation has a number of advantages. We demonstrate that by using non-uniform bins in μ, we can isolate plane-of-sky (angular) systematics to a narrow bin at 0μ ≅ while eliminating the contamination from all other bins. We also show that the covariance matrix of clustering wedges binned uniformly in μ becomes ill-conditioned when combining multipoles up to large values of ℓ{sub max}, but that the problem can be avoided with non-uniform binning. As an example, we present results using ℓ{sub max}=16, for which our procedure requires a factor of 3.4 fewer FFTs than the Cartesian method, while removing the first μ bin leads only to a 7% increase in statistical error on f σ{sub 8}, as compared to a 54% increase with ℓ{sub max}=4.
An optimal FFT-based anisotropic power spectrum estimator
Hand, Nick; Li, Yin; Slepian, Zachary; Seljak, Uroš
2017-07-01
Measurements of line-of-sight dependent clustering via the galaxy power spectrum's multipole moments constitute a powerful tool for testing theoretical models in large-scale structure. Recent work shows that this measurement, including a moving line-of-sight, can be accelerated using Fast Fourier Transforms (FFTs) by decomposing the Legendre polynomials into products of Cartesian vectors. Here, we present a faster, optimal means of using FFTs for this measurement. We avoid redundancy present in the Cartesian decomposition by using a spherical harmonic decomposition of the Legendre polynomials. With this method, a given multipole of order l requires only 2l+1 FFTs rather than the (l+1)(l+2)/2 FFTs of the Cartesian approach. For the hexadecapole (l = 4), this translates to 40% fewer FFTs, with increased savings for higher l. The reduction in wall-clock time enables the calculation of finely-binned wedges in P(k,μ), obtained by computing multipoles up to a large lmax and combining them. This transformation has a number of advantages. We demonstrate that by using non-uniform bins in μ, we can isolate plane-of-sky (angular) systematics to a narrow bin at 0μ simeq while eliminating the contamination from all other bins. We also show that the covariance matrix of clustering wedges binned uniformly in μ becomes ill-conditioned when combining multipoles up to large values of lmax, but that the problem can be avoided with non-uniform binning. As an example, we present results using lmax=16, for which our procedure requires a factor of 3.4 fewer FFTs than the Cartesian method, while removing the first μ bin leads only to a 7% increase in statistical error on f σ8, as compared to a 54% increase with lmax=4.
Lesmana, E.; Chaerani, D.; Khansa, H. N.
2018-03-01
Energy-Saving Generation Dispatch (ESGD) is a scheme made by Chinese Government in attempt to minimize CO2 emission produced by power plant. This scheme is made related to global warming which is primarily caused by too much CO2 in earth’s atmosphere, and while the need of electricity is something absolute, the power plants producing it are mostly thermal-power plant which produced many CO2. Many approach to fulfill this scheme has been made, one of them came through Minimum Cost Flow in which resulted in a Quadratically Constrained Quadratic Programming (QCQP) form. In this paper, ESGD problem with Minimum Cost Flow in QCQP form will be solved using Lagrange’s Multiplier Method
Кирисов, Игорь Геннадиевич; Овчаренко, Татьяна Ивановна
2014-01-01
В статье рассмотрены особенности разных энергосберегающих технологий, которые можно применить в системах электроснабжения промышленных предприятий. Проведены расчеты, подтверждающие целесообразность замены недозагруженных асинхронных двигателей на двигатели меньшей мощности. The paper deals with the speci cs of different energy-saving technologies that can be applied in electrical power supply systems of industrial enterprises. The paper presents calculations that corroborate ...
Energy Technology Data Exchange (ETDEWEB)
Schnell, Wolf-Dieter [Ingenieurbuero fuer Energietechnik, Langenargen/Bodensee (Germany)
2009-07-01
Industrial-scale users of cooling water use bigger and higher natural-draught cooling towers to improve recirculation cooling. Smaller and medium-sized consumers as a rule use ventilation cooling towers.The market offers a wide choice of efficient products. At the same time, competition enforces savings so that often these ventilation cooling towers have no control option. However, optimum operation in the winter season necessitates variable air supply which is also a cost factor that can help to compensate the higher cost incurred in other seasons. (orig.)
Optimal power flow based on glow worm-swarm optimization for three-phase islanded microgrids
DEFF Research Database (Denmark)
Quang, Ninh Nguyen; Sanseverino, Eleonora Riva; Di Silvestre, Maria Luisa
2014-01-01
This paper presents an application of the Glowworm Swarm Optimization method (GSO) to solve the optimal power flow problem in three-phase islanded microgrids equipped with power electronics dc-ac inverter interfaced distributed generation units. In this system, the power injected by the distribut...
Energy Technology Data Exchange (ETDEWEB)
Simpkins, Travis; Anderson, Kate; Cutler, Dylan; Olis, Dan
2016-11-01
Solar-plus-storage systems can achieve significant utility savings in behind-the-meter deployments in buildings, campuses, or industrial sites. Common applications include demand charge reduction, energy arbitrage, time-shifting of excess photovoltaic (PV) production, and selling ancillary services to the utility grid. These systems can also offer some energy resiliency during grid outages. It is often difficult to quantify the amount of resiliency that these systems can provide, however, and this benefit is often undervalued or omitted during the design process. We propose a method for estimating the resiliency that a solar-plus-storage system can provide at a given location. We then present an optimization model that can optimally size the system components to minimize the lifecycle cost of electricity to the site, including the costs incurred during grid outages. The results show that including the value of resiliency during the feasibility stage can result in larger systems and increased resiliency.
International Nuclear Information System (INIS)
Huang, Yanjun; Khajepour, Amir; Ding, Haitao; Bagheri, Farshid; Bahrami, Majid
2017-01-01
Highlights: • A novel two-layer energy-saving controller for automotive A/C-R system is developed. • A set-point optimizer at the outer loop is designed based on the steady state model. • A sliding mode controller in the inner loop is built. • Extensively experiments studies show that about 9% energy can be saving by this controller. - Abstract: This paper presents an energy-saving controller for automotive air-conditioning/refrigeration (A/C-R) systems. With their extensive application in homes, industry, and vehicles, A/C-R systems are consuming considerable amounts of energy. The proposed controller consists of two different time-scale layers. The outer or the slow time-scale layer called a set-point optimizer is used to find the set points related to energy efficiency by using the steady state model; whereas, the inner or the fast time-scale layer is used to track the obtained set points. In the inner loop, thanks to its robustness, a sliding mode controller (SMC) is utilized to track the set point of the cargo temperature. The currently used on/off controller is presented and employed as a basis for comparison to the proposed controller. More importantly, the real experimental results under several disturbed scenarios are analysed to demonstrate how the proposed controller can improve performance while reducing the energy consumption by 9% comparing with the on/off controller. The controller is suitable for any type of A/C-R system even though it is applied to an automotive A/C-R system in this paper.
Self-supporting power plant. Capturing evaporated water and save energy a new source of water
Energy Technology Data Exchange (ETDEWEB)
Daal, Ludwin; Vos, Frank de [KEMA Netherlands BV, Arnhem (Netherlands). Process and Cooling Water; KEMA Energy Consulting Co.Ltd, Beijing (China); Wageningen Univ. (Netherlands). Environmental Systems Analysis; Heijboer, Rob [KEMA Netherlands BV, Arnhem (Netherlands). Process and Cooling Water; Bekker, Bert [KEMA Energy Consulting Co.Ltd, Beijing (China); Gao, Xiu Xiu [Wageningen Univ. (Netherlands). Environmental Systems Analysis
2013-07-01
One of the major challenges of this century is the provision of water for a growing population and industry. The shortage in water resources in arid areas requires the availability of more efficient and cheaper water production processes. In some arid regions water is even more important than electricity. A large source of water is found in the form of evaporated water emitted from different industrial processes. If for example 20% of the evaporated water from the flue gas stream of a coal fired power plant would be captured, the plant would be self-supporting from a process water point of view. This is about 30m{sup 3} of water per hour. The results of the proof of principle project (2001-2008) show that >40% recovery can be achieved. Also an overall energy efficiency improvement can be achieved for industrial plants that reheat their flue gases. Calculations show that this can be about 1% overall efficiency for a coal fired power plant utilizing flue gas reheating. With an installed capacity of more than 600GWe in China, this energy saving results in a very large economic and fuel (coal) impact. This energy efficiency will most likely be the driving force to implement the technology in both water rich and water poor regions. For the capture of evaporated water no chemicals are used, there is no waste water formed and corrosion attack in stacks is mitigated. These results have led to the set up of a large international project named CapWa which aims to produce a membrane modular system suitable for industrial applications within 2-3years. The produced demin water from this system should be competitive with existing demin water technologies. The starting point will be the water vapour selective composite membranes that are developed in the proof of principle project. The CapWa project started in 2010 and consists of 14 partners of which 9 from the EU, 3 from the African continent and 2 from the Middle East.
System-level power optimization for real-time distributed embedded systems
Luo, Jiong
Power optimization is one of the crucial design considerations for modern electronic systems. In this thesis, we present several system-level power optimization techniques for real-time distributed embedded systems, based on dynamic voltage scaling, dynamic power management, and management of peak power and variance of the power profile. Dynamic voltage scaling has been widely acknowledged as an important and powerful technique to trade off dynamic power consumption and delay. Efficient dynamic voltage scaling requires effective variable-voltage scheduling mechanisms that can adjust voltages and clock frequencies adaptively based on workloads and timing constraints. For this purpose, we propose static variable-voltage scheduling algorithms utilizing criticalpath driven timing analysis for the case when tasks are assumed to have uniform switching activities, as well as energy-gradient driven slack allocation for a more general scenario. The proposed techniques can achieve closeto-optimal power savings with very low computational complexity, without violating any real-time constraints. We also present algorithms for power-efficient joint scheduling of multi-rate periodic task graphs along with soft aperiodic tasks. The power issue is addressed through both dynamic voltage scaling and power management. Periodic task graphs are scheduled statically. Flexibility is introduced into the static schedule to allow the on-line scheduler to make local changes to PE schedules through resource reclaiming and slack stealing, without interfering with the validity of the global schedule. We provide a unified framework in which the response times of aperiodic tasks and power consumption are dynamically optimized simultaneously. Interconnection network fabrics point to a new generation of power-efficient and scalable interconnection architectures for distributed embedded systems. As the system bandwidth continues to increase, interconnection networks become power/energy limited as
Joint optimization of regional water-power systems
DEFF Research Database (Denmark)
Cardenal, Silvio Javier Pereira; Mo, Birger; Gjelsvik, Anders
2016-01-01
using stochastic dual dynamic programming. The results showed that current water allocation to hydropower producers in basins with high irrigation productivity, and to irrigation users in basins with high hydropower productivity was sub-optimal. Optimal allocation was achieved by managing reservoirs...... for joint optimization of water and electric power systems was developed in order to identify methodologies to assess the broader interactions between water and energy systems. The proposed method is to include water users and power producers into an economic optimization problem that minimizes the cost...... of power production and maximizes the benefits of water allocation, subject to constraints from the power and hydrological systems. The method was tested on the Iberian Peninsula using simplified models of the seven major river basins and the power market. The optimization problem was successfully solved...
Karlsson, Jonathan
2012-01-01
The aim of this project was to generate knowledge to enable us to take advantage of heat storage in heavy building structures with regard to as energy savings, better thermal indoor climate, and reduced peak powers. This could include buildings that can function without energy input during cold periods, buildings that give a robust indoor climate without installed cooling, and buildings with good thermal comfort also in case of higher outdoor temperatures resulting from global warming. To rea...
A solution to the optimal power flow using multi-verse optimizer
Directory of Open Access Journals (Sweden)
Bachir Bentouati
2016-12-01
Full Text Available In this work, the most common problem of the modern power system named optimal power flow (OPF is optimized using the novel meta-heuristic optimization Multi-verse Optimizer(MVO algorithm. In order to solve the optimal power flow problem, the IEEE 30-bus and IEEE 57-bus systems are used. MVO is applied to solve the proposed problem. The problems considered in the OPF problem are fuel cost reduction, voltage profile improvement, voltage stability enhancement. The obtained results are compared with recently published meta-heuristics. Simulation results clearly reveal the effectiveness and the rapidity of the proposed algorithm for solving the OPF problem.
Optimization Criteria of Power Transformer Operation
Directory of Open Access Journals (Sweden)
A. A. Gonchar
2006-01-01
Full Text Available It has been shown that minimum losses in active power of a power transformer do not correspond to its maximum efficiency. For a transformer being operated there are no so called «zones of its economical operation». In this case strictly specified value of active power losses corresponds to a particular current of the winding.
Optimal power flow by particle swarm optimization with an aging ...
African Journals Online (AJOL)
DR OKE
2002), evolutionary programming (EP) (Somasundaram et al. ... concepts, a modified PSO called as PSO with aging leader and challenges (ALC-PSO) is ... system is adopted as standard power network whose OPF problem is solved with the ...
International Nuclear Information System (INIS)
Liu Zhihui; Wei Fangxin; Liu Xiaomin
2014-01-01
By means of osculation value method, several provinces are selected to study the energy saving and emission reduction effect of nuclear power from provincial range according to the statistic data in 2010. Theoretically, nuclear power effect is reducing the consumption of non-renewable energy such as coal and reducing the release of pollutants such as CO 2 . The result shows that the comprehensive evaluation of energy saving and emission reduction effect in Zhejiang and Jiangsu provinces are the best. In comparison, Guangdong province falls behind Hubei and Fujian provinces. Total consumption of coal per unit of GDP in Guangdong, Zhejiang, and Jiangsu provinces is apparently lower than that of Hebei, Shanxi, Liaoning, and Hubei provinces. However, total release of SO 2 and NOx, etc. is apparently reduced in provinces with nuclear power, compared with provinces without nuclear power. But total release of CO 2 from thermal power generation (coal) per unit of GDP is not apparently reduced in provinces with nuclear power than those without. (authors)
The optimization of energy saving systems on the basis of complex use of renewable sources of energy
Energy Technology Data Exchange (ETDEWEB)
Moiseykina, I [Engineering Thermophysics Institute, Ukraine National Academy of Sciences, Kiev (Ukraine)
1998-12-31
The use of renewable sources of energy (sun, wind, geothermal, biomass) results in the saving of organic fuel and improvement of environment ecology. The complex systems are the most effective systems based on the several kinds of renewable energy sources with special regard to specific local features (resources, engineering possibilities, energy needs). The similar complex systems are capable to fill in the schedule of energy consumption by the best way, to supply the consumer with different kinds of energy (heat, electricity) during the whole year. They can be used for promoting the most effective solution of power supply problems by the means of using the non-traditional energy sources. The arrangement by units is proposed for the complex system that are being developed for power supply by the means of using renewable sources of energy. In complex systems the particular attention was given to energy accumulation problem, to thermotransformers, working on use of renewable sources of energy and possessing a number of advantages as compared to the other systems (the absence of moving parts, simplicity of service, etc.) Nontraditional complex energy saving systems (CESS) includes the geothermal circulating system (GCS), hello heat collector (HHC) with heating storage (HS) 2 refs.
The optimization of energy saving systems on the basis of complex use of renewable sources of energy
Energy Technology Data Exchange (ETDEWEB)
Moiseykina, I. [Engineering Thermophysics Institute, Ukraine National Academy of Sciences, Kiev (Ukraine)
1997-12-31
The use of renewable sources of energy (sun, wind, geothermal, biomass) results in the saving of organic fuel and improvement of environment ecology. The complex systems are the most effective systems based on the several kinds of renewable energy sources with special regard to specific local features (resources, engineering possibilities, energy needs). The similar complex systems are capable to fill in the schedule of energy consumption by the best way, to supply the consumer with different kinds of energy (heat, electricity) during the whole year. They can be used for promoting the most effective solution of power supply problems by the means of using the non-traditional energy sources. The arrangement by units is proposed for the complex system that are being developed for power supply by the means of using renewable sources of energy. In complex systems the particular attention was given to energy accumulation problem, to thermotransformers, working on use of renewable sources of energy and possessing a number of advantages as compared to the other systems (the absence of moving parts, simplicity of service, etc.) Nontraditional complex energy saving systems (CESS) includes the geothermal circulating system (GCS), hello heat collector (HHC) with heating storage (HS) 2 refs.
Optimization of the triple-pressure combined cycle power plant
Directory of Open Access Journals (Sweden)
Alus Muammer
2012-01-01
Full Text Available The aim of this work was to develop a new system for optimization of parameters for combined cycle power plants (CCGTs with triple-pressure heat recovery steam generator (HRSG. Thermodynamic and thermoeconomic optimizations were carried out. The objective of the thermodynamic optimization is to enhance the efficiency of the CCGTs and to maximize the power production in the steam cycle (steam turbine gross power. Improvement of the efficiency of the CCGT plants is achieved through optimization of the operating parameters: temperature difference between the gas and steam (pinch point P.P. and the steam pressure in the HRSG. The objective of the thermoeconomic optimization is to minimize the production costs per unit of the generated electricity. Defining the optimal P.P. was the first step in the optimization procedure. Then, through the developed optimization process, other optimal operating parameters (steam pressure and condenser pressure were identified. The developed system was demonstrated for the case of a 282 MW CCGT power plant with a typical design for commercial combined cycle power plants. The optimized combined cycle was compared with the regular CCGT plant.
Techno-economic design optimization of solar thermal power plants
Morin, G.
2011-01-01
A holistic view is essential in the engineering of technical systems. This thesis presents an integrative approach for designing solar thermal power plants. The methodology is based on a techno-economic plant model and a powerful optimization algorithm. Typically, contemporary design methods treat technical and economic parameters and sub-systems separately, making it difficult or even impossible to realize the full optimization potential of power plant systems. The approach presented here ov...
International Nuclear Information System (INIS)
Wei, Chu; Löschel, Andreas; Liu, Bing
2015-01-01
In the context of soaring demand for electricity, mitigating and controlling greenhouse gas emissions is a great challenge for China's power sector. Increasing attention has been placed on the evaluation of energy efficiency and CO 2 abatement potential in the power sector. However, studies at the micro-level are relatively rare due to serious data limitations. This study uses the 2004 and 2008 Census data of Zhejiang province to construct a non-parametric frontier in order to assess the abatement space of energy and associated CO 2 emission from China's coal-fired power enterprises. A Weighted Russell Directional Distance Function (WRDDF) is applied to construct an energy-saving potential index and a CO 2 emission-abatement potential index. Both indicators depict the inefficiency level in terms of energy utilization and CO 2 emissions of electric power plants. Our results show a substantial variation of energy-saving potential and CO 2 abatement potential among enterprises. We find that large power enterprises are less efficient in 2004, but become more efficient than smaller enterprises in 2008. State-owned enterprises (SOE) are not significantly different in 2008 from 2004, but perform better than their non-SOE counterparts in 2008. This change in performance for large enterprises and SOE might be driven by the “top-1000 Enterprise Energy Conservation Action” that was implemented in 2006. - Highlights: • Energy-saving potential and CO 2 abatement-potential for Chinese power enterprise are evaluated. • The potential to curb energy and emission shows great variation and dynamic changes. • Large enterprise is less efficient than small enterprise in 2004, but more efficient in 2008. • The state-owned enterprise performs better than non-state-owned enterprise in 2008
Optimal Power Flow by Interior Point and Non Interior Point Modern Optimization Algorithms
Directory of Open Access Journals (Sweden)
Marcin Połomski
2013-03-01
Full Text Available The idea of optimal power flow (OPF is to determine the optimal settings for control variables while respecting various constraints, and in general it is related to power system operational and planning optimization problems. A vast number of optimization methods have been applied to solve the OPF problem, but their performance is highly dependent on the size of a power system being optimized. The development of the OPF recently has tracked significant progress both in numerical optimization techniques and computer techniques application. In recent years, application of interior point methods to solve OPF problem has been paid great attention. This is due to the fact that IP methods are among the fastest algorithms, well suited to solve large-scale nonlinear optimization problems. This paper presents the primal-dual interior point method based optimal power flow algorithm and new variant of the non interior point method algorithm with application to optimal power flow problem. Described algorithms were implemented in custom software. The experiments show the usefulness of computational software and implemented algorithms for solving the optimal power flow problem, including the system model sizes comparable to the size of the National Power System.
Parameters optimization for magnetic resonance coupling wireless power transmission.
Li, Changsheng; Zhang, He; Jiang, Xiaohua
2014-01-01
Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.
Optimization design for drain to nuclear power condenser
International Nuclear Information System (INIS)
Ding Jiapeng; Jiang Chengren
2010-01-01
Characters and varieties of drain to nuclear power condenser are discussed in this paper. Take the main steam system of a nuclear power as an example, normal and detailed optimization design are introduced, related expatiate are used as a reference for the drain of other systems. According to the characters of nuclear power instant operation, the influence and needed actions related with the optimization design are also analyzed. Based on the above research, the scheme has been carried out in a nuclear power station and safety for the condenser operation of the nuclear power has been improved largely. (authors)
International Nuclear Information System (INIS)
Bruderer Enzler, Heidi; Diekmann, Andreas; Meyer, Reto
2014-01-01
Why do people sometimes refrain from saving energy even if it would pay off in monetary terms? Subjective discount rates present one possible explanation for this lack of foresight, but little is known about their level and reliability in the general population. With regard to behavior, persons with lower discount rates are expected to accept additional costs upfront more readily than those with higher discount rates. Based on a representative nation-wide study, the Swiss Environmental Survey 2007, and a follow-up survey, our analyses reveal that on average subjective discount rates are well above market interest rates and moderately stable over a time interval of four years. Income and education are negatively correlated with discount rates. Contrary to expectations, we did not find convincing support for an impact of discount rates on energy saving behavior. - Highlights: • Results of a large panel study in Switzerland. • Mean subjective discount rates in population are well above market interest rates. • Subjective discount rates are moderately stable over four years. • Theory suggests impact of subjective discount rates on energy saving behavior. • However, subjective discount rates do not contribute to explanation of energy saving behavior
12 CFR 560.30 - General lending and investment powers of Federal savings associations.
2010-01-01
.... Commercial paper and corporate debt securities 5(c)(2)(D) Up to 35% of total assets. 2,3 Community...) None. 6 Finance leasing 5(c)(1)(B), 5(c)(2)(A), 5(c)(2)(B), 5(c)(2)(D) Based on purpose and property... corporate debt securities must be aggregated with the Federal savings association's investment in consumer...
A decoupled power flow algorithm using particle swarm optimization technique
International Nuclear Information System (INIS)
Acharjee, P.; Goswami, S.K.
2009-01-01
A robust, nondivergent power flow method has been developed using the particle swarm optimization (PSO) technique. The decoupling properties between the power system quantities have been exploited in developing the power flow algorithm. The speed of the power flow algorithm has been improved using a simple perturbation technique. The basic power flow algorithm and the improvement scheme have been designed to retain the simplicity of the evolutionary approach. The power flow is rugged, can determine the critical loading conditions and also can handle the flexible alternating current transmission system (FACTS) devices efficiently. Test results on standard test systems show that the proposed method can find the solution when the standard power flows fail.
[Optimization of Energy Saving Measures with ABR-MBR Integrated Process].
Wu, Peng; Lu, Shuang-jun; Xu, Yue-zhong; Liu, Jie; Shen, Yao-liang
2015-08-01
High energy consumption and membrane fouling are important factors that limit the wide use of membrane bioreactor (MBR). In order to reduce energy consumption and delay the process of membrane fouling, the process of anaerobic baffled reactor (ABR)-MBR was used to treat domestic sewage. The structure of the process and conditions of nitrogen and phosphorus removal were optimized in this study. The results showed that energy consumption was reduced by 43% through optimizing the structure of ABR-MBR process. Meanwhile, the process achieved a high level of COD, NH: -N, TN and TP removal, with the average removal efficiencies of 91%, 85%, 76% and 86%, respectively. In addition, the added particulate media could effectively delay membrane fouling, while the formation process of membrane fouling was changed. The extracted amount of carbohydrates increased while the amount of proteins decreased. Finally, the potential was enhanced for the practical application of MBR.
Multi-objective optimal power flow with FACTS devices
International Nuclear Information System (INIS)
Basu, M.
2011-01-01
This paper presents multi-objective differential evolution to optimize cost of generation, emission and active power transmission loss of flexible ac transmission systems (FACTS) device-equipped power systems. In the proposed approach, optimal power flow problem is formulated as a multi-objective optimization problem. FACTS devices considered include thyristor controlled series capacitor (TCSC) and thyristor controlled phase shifter (TCPS). The proposed approach has been examined and tested on the modified IEEE 30-bus and 57-bus test systems. The results obtained from the proposed approach have been compared with those obtained from nondominated sorting genetic algorithm-II, strength pareto evolutionary algorithm 2 and pareto differential evolution.
Turbine Control Strategies for Wind Farm Power Optimization
DEFF Research Database (Denmark)
Mirzaei, Mahmood; Göçmen Bozkurt, Tuhfe; Giebel, Gregor
2015-01-01
In recent decades there has been increasing interest in green energies, of which wind energy is the most important one. In order to improve the competitiveness of the wind power plants, there are ongoing researches to decrease cost per energy unit and increase the efficiency of wind turbines...... and wind farms. One way of achieving these goals is to optimize the power generated by a wind farm. One optimization method is to choose appropriate operating points for the individual wind turbines in the farm. We have made three models of a wind farm based on three difference control strategies...... the generated power by changing the power reference of the individual wind turbines. We use the optimization setup to compare power production of the wind farm models. This paper shows that for the most frequent wind velocities (below and around the rated values), the generated powers of the wind farms...
Energy Technology Data Exchange (ETDEWEB)
Burton, E.; Wang, L.; Gonder, J.; Brooker, A.; Konan, A.
2015-02-10
This presentation discusses the fuel savings potential from future in-motion wireless power transfer. There is an extensive overlap in road usage apparent across regional vehicle population, which occurs primarily on high-capacity roads--1% of roads are used for 25% of the vehicle miles traveled. Interstates and highways make up between 2.5% and 4% of the total roads within the Consolidated Statistical Areas (CSAs), which represent groupings of metropolitan and/or micropolitan statistical areas. Mileage traveled on the interstates and highways ranges from 54% in California to 24% in Chicago. Road electrification could remove range restrictions of electric vehicles and increase the fuel savings of PHEVs or HEVs if implemented on a large scale. If 1% of the road miles within a geographic area are electrified, 25% of the fuel used by a 'fleet' of vehicles enabled with the technology could be displaced.
An Optimal Power Flow (OPF) Method with Improved Power System Stability
DEFF Research Database (Denmark)
Su, Chi; Chen, Zhe
2010-01-01
This paper proposes an optimal power flow (OPF) method taking into account small signal stability as additional constraints. Particle swarm optimization (PSO) algorithm is adopted to realize the OPF process. The method is programmed in MATLAB and implemented to a nine-bus test power system which...... has large-scale wind power integration. The results show the ability of the proposed method to find optimal (or near-optimal) operating points in different cases. Based on these results, the analysis of the impacts of wind power integration on the system small signal stability has been conducted....
High performance magnet power supply optimization
International Nuclear Information System (INIS)
Jackson, L.T.
1975-01-01
Three types of magnet power supply systems for the joint LBL-SLAC proposed accelerator PEP are discussed. The systems considered include a firing circuit and six-pulse controlled rectifier, transistor systems, and a chopper system. (U.S.)
Optimal electricity market for wind power
International Nuclear Information System (INIS)
Holttinen, H.
2005-01-01
This paper is about electricity market operation when looking from the wind power producers' point of view. The focus in on market time horizons: how many hours there is between the closing and delivering the bids. The case is for the Nordic countries, the Nordpool electricity market and the Danish wind power production. Real data from year 2001 was used to study the benefits of a more flexible market to wind power producer. As a result of reduced regulating market costs from better hourly predictions to the market, wind power producer would gain up to 8% more if the time between market bids and delivery was shortened from the day ahead Elspot market (hourly bids by noon for 12-36 h ahead). An after sales market where surplus or deficit production could be traded 2 h before delivery could benefit the producer almost as much, gaining 7%
2017-01-01
Power electronics belongs to the future key technologies in order to increase system efficiency as well as performance in automotive and energy saving applications. Silicon is the major material for electronic switches since decades. Advanced fabrication processes and sophisticated electronic device designs have optimized the silicon electronic device performance almost to their theoretical limit. Therefore, to increase the system performance, new materials that exhibit physical and chemical properties beyond silicon need to be explored. A number of wide bandgap semiconductors like silicon carbide, gallium nitride, gallium oxide, and diamond exhibit outstanding characteristics that may pave the way to new performance levels. The review will introduce these materials by (i) highlighting their properties, (ii) introducing the challenges in materials growth, and (iii) outlining limits that need innovation steps in materials processing to outperform current technologies. PMID:29200530
Wellmann, Peter J
2017-11-17
Power electronics belongs to the future key technologies in order to increase system efficiency as well as performance in automotive and energy saving applications. Silicon is the major material for electronic switches since decades. Advanced fabrication processes and sophisticated electronic device designs have optimized the silicon electronic device performance almost to their theoretical limit. Therefore, to increase the system performance, new materials that exhibit physical and chemical properties beyond silicon need to be explored. A number of wide bandgap semiconductors like silicon carbide, gallium nitride, gallium oxide, and diamond exhibit outstanding characteristics that may pave the way to new performance levels. The review will introduce these materials by (i) highlighting their properties, (ii) introducing the challenges in materials growth, and (iii) outlining limits that need innovation steps in materials processing to outperform current technologies.
Directory of Open Access Journals (Sweden)
Anuradha Pughat
2016-09-01
Full Text Available Dynamic voltage scaling contributes to a significant amount of power saving, especially in the energy constrained wireless sensor networks (WSNs. Existing dynamic voltage scaling techniques make the system slower and ignore the event miss rate. This results in degradation of the system performance when there is non-stationary workload at input. The overhead due to transition between voltage level and discrete voltage levels are also the limitations of available dynamic voltage scaling (DVS techniques at sensor node (SN. This paper proposes a workload dependent DVS based MSP430 controller model used for SN. An online gradient estimation technique has been used to optimize power and performance trade-offs. The analytical results are validated with the simulation results obtained using simulation tool “SimEvents” and compared with the available AT9OS8535 controller. Based on the stochastic workload, the controller's input voltage, operational frequency, utilization, and average wait time of events are obtained.
Decision Optimization for Power Grid Operating Conditions with High- and Low-Voltage Parallel Loops
Directory of Open Access Journals (Sweden)
Dong Yang
2017-05-01
Full Text Available With the development of higher-voltage power grids, the high- and low-voltage parallel loops are emerging, which lead to energy losses and even threaten the security and stability of power systems. The multi-infeed high-voltage direct current (HVDC configurations widely appearing in AC/DC interconnected power systems make this situation even worse. Aimed at energy saving and system security, a decision optimization method for power grid operating conditions with high- and low-voltage parallel loops is proposed in this paper. Firstly, considering hub substation distribution and power grid structure, parallel loop opening schemes are generated with GN (Girvan-Newman algorithms. Then, candidate opening schemes are preliminarily selected from all these generated schemes based on a filtering index. Finally, with the influence on power system security, stability and operation economy in consideration, an evaluation model for candidate opening schemes is founded based on analytic hierarchy process (AHP. And a fuzzy evaluation algorithm is used to find the optimal scheme. Simulation results of a New England 39-bus system and an actual power system validate the effectiveness and superiority of this proposed method.
OPF-Based Optimal Location of Two Systems Two Terminal HVDC to Power System Optimal Operation
Directory of Open Access Journals (Sweden)
Mehdi Abolfazli
2013-04-01
Full Text Available In this paper a suitable mathematical model of the two terminal HVDC system is provided for optimal power flow (OPF and optimal location based on OPF such power injection model. The ability of voltage source converter (VSC-based HVDC to independently control active and reactive power is well represented by the model. The model is used to develop an OPF-based optimal location algorithm of two systems two terminal HVDC to minimize the total fuel cost and active power losses as objective function. The optimization framework is modeled as non-linear programming (NLP and solved by Matlab and GAMS softwares. The proposed algorithm is implemented on the IEEE 14- and 30-bus test systems. The simulation results show ability of two systems two terminal HVDC in improving the power system operation. Furthermore, two systems two terminal HVDC is compared by PST and OUPFC in the power system operation from economical and technical aspects.
Optimal Output of Distributed Generation Based On Complex Power Increment
Wu, D.; Bao, H.
2017-12-01
In order to meet the growing demand for electricity and improve the cleanliness of power generation, new energy generation, represented by wind power generation, photovoltaic power generation, etc has been widely used. The new energy power generation access to distribution network in the form of distributed generation, consumed by local load. However, with the increase of the scale of distribution generation access to the network, the optimization of its power output is becoming more and more prominent, which needs further study. Classical optimization methods often use extended sensitivity method to obtain the relationship between different power generators, but ignore the coupling parameter between nodes makes the results are not accurate; heuristic algorithm also has defects such as slow calculation speed, uncertain outcomes. This article proposes a method called complex power increment, the essence of this method is the analysis of the power grid under steady power flow. After analyzing the results we can obtain the complex scaling function equation between the power supplies, the coefficient of the equation is based on the impedance parameter of the network, so the description of the relation of variables to the coefficients is more precise Thus, the method can accurately describe the power increment relationship, and can obtain the power optimization scheme more accurately and quickly than the extended sensitivity method and heuristic method.
Optimal prediction intervals of wind power generation
DEFF Research Database (Denmark)
Wan, Can; Wu, Zhao; Pinson, Pierre
2014-01-01
direct optimization of both the coverage probability and sharpness to ensure the quality. The proposed method does not involve the statistical inference or distribution assumption of forecasting errors needed in most existing methods. Case studies using real wind farm data from Australia have been...
Modeling and optimization of an electric power distribution network ...
African Journals Online (AJOL)
Modeling and optimization of an electric power distribution network planning system using ... of the network was modelled with non-linear mathematical expressions. ... given feasible locations, re-conductoring of existing feeders in the network, ...
Optimization of the commissioning period of nuclear power plant
International Nuclear Information System (INIS)
Hou Ganglian; Li Chunyue
2014-01-01
Due to current equipment manufacture capacity, construction experience and other factors, commissioning of nuclear power projects was used to be postponed, which could lead to delay of the whole project. Based on the actual situation, optimization of commissioning period and its logic could be an effective way to improve this situation to some extent. Based on previous practice and experience in the schedule management for the commissioning nuclear power projects, this paper analyzes and discusses the characteristics of make commissioning plan and the difficulties of program implementation and strategies of commissioning plan optimization, discusses and presents ways of dynamic plan adjustment and optimization at the vision of entire project, synthesizes the methods of time management through commissioning itself, interface and management, expounds measures for the timing and optimization of commissioning schedule and commissioning period, and sums up the ways of optimization of commissioning period, improving management capabilities and control of optimization principles. (authors)
Boivin, David; Bigot-Astruc, Marianne; De Montmorillon, Louis-Anne; Provost, Lionel; Sillard, Pierre; Bergonzo, Aurélien
2009-02-01
After many years of expectations, Fiber To The Home (FTTH) has finally become a reality with a wide number of projects already running worldwide and growing. Optical fiber is inevitably taking more and more importance in our environment, but for many good reasons, the space we are truly willing or able to allocate to it remains limited. These installation constrainsts have turned into additional requirements that need to be addressed for both active and passive components. If exceptional bending performances obtained without degrading backward compatibilities is a pre-requisite to deployment success,1 other parameters also need to be carefully taken into account when designing the ideal candidate for use in confined environments. Among them, one can cite the bend loss homogeneity over length and bending directions, the resistance to high optical power under bending and the tolerance to modal noise. In this paper, we present the design and performances of a bend insensitive fiber optimized towards more space savings and miniaturization of components. In addition to exceptional bending performances - lower than 0.1 dB/turn over a 5 mm bending radius -, its design guarantees impressive homogeneity levels and enhanced safety margins for high power applications while being still resistant to modal noise. Successfull cleave- and splice-ability results are finally presented, making this fiber ideally suited for use in components, pigtails and patchcords.
Optimization of air injection parameters toward optimum fuel saving effect for ships
Lee, Inwon; Park, Seong Hyeon
2016-11-01
Air lubrication method is the most promising commercial strategy for the frictional drag reduction of ocean going vessels. Air bubbles are injected through the array of holes or the slots installed onto the flat bottom surface of vessel and a sufficient supply of air is required to ensure the formation of stable air layer by the by the coalescence of the bubbles. The air layer drag reduction becomes economically meaningful when the power gain through the drag reduction exceeds the pumping power consumption. In this study, a model ship of 50k medium range tanker is employed to investigate air lubrication method. The experiments were conducted in the 100m long towing tank facility at the Pusan National University. To create the effective air lubrication with lower air flow rate, various configurations including the layout of injection holes, employment of side fences and static trim have been tested. In the preliminary series of model tests, the maximum 18.13%(at 15kts) of reduction of model resistance was achieved. This research was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MEST) through GCRC-SOP (Grant No. 2011-0030013).
Numerical optimization for separation power of gas centrifuge
International Nuclear Information System (INIS)
Jiang Dongjun; Zeng Shi; Liu Bing
2012-01-01
In order to obtain higher separation power of the gas centrifuge, the code was developed to solve the flow-field of the counter-current to acquire the separation power, which was integrated with the iSight software, so a numerical optimization model for separation power was presented, in which the driver conditions and the geometry parameters of the waste baffle were optimized to get the maximum separation power using the sequential quadratic programming arithmetic, and the 12% higher results was acquired, which shows the feasibility of this method. The results also note that the separation power of gas centrifuge is sensitive to the driver conditions and the structure parameters of the waste baffle, so it is necessary to perform the optimization calculation for the certain gas centrifuge model. (authors)
Optimized Power Dispatch Strategy for Offshore Wind Farms
DEFF Research Database (Denmark)
Hou, Peng; Hu, Weihao; Zhang, Baohua
2016-01-01
which are related to electrical system topology. This paper proposed an optimized power dispatch strategy (OPD) for minimizing the levelized production cost (LPC) of a wind farm. Particle swarm optimization (PSO) is employed to obtain final solution for the optimization problem. Both regular shape......Maximizing the power production of offshore wind farms using proper control strategy has become an important issue for wind farm operators. However, the power transmitted to the onshore substation (OS) is not only related to the power production of each wind turbine (WT) but also the power losses...... and irregular shape wind farm are chosen for the case study. The proposed dispatch strategy is compared with two other control strategies. The simulation results show the effectiveness of the proposed strategy....
Optimization of the Energy Output of Osmotic Power Plants
Directory of Open Access Journals (Sweden)
Florian Dinger
2013-01-01
Full Text Available On the way to a completely renewable energy supply, additional alternatives to hydroelectric, wind, and solar power have to be investigated. Osmotic power is such an alternative with a theoretical global annual potential of up to 14400 TWh (70% of the global electricity consumption of 2008 per year. It utilizes the phenomenon that upon the mixing of fresh water and oceanic salt water (e.g., at a river mouth, around 2.88 MJ of energy per 1 m3 of fresh water is released. Here, we describe a new approach to derive operational parameter settings for osmotic power plants using a pressure exchanger for optimal performance, either with respect to maximum generated power or maximum extracted energy. Up to now, only power optimization is discussed in the literature, but when considering the fresh water supply as a limiting factor, the energy optimization appears as the challenging task.
Evolutionary Computing for Intelligent Power System Optimization and Control
DEFF Research Database (Denmark)
This new book focuses on how evolutionary computing techniques benefit engineering research and development tasks by converting practical problems of growing complexities into simple formulations, thus largely reducing development efforts. This book begins with an overview of the optimization the...... theory and modern evolutionary computing techniques, and goes on to cover specific applications of evolutionary computing to power system optimization and control problems....
Optimal Selective Harmonic Control for Power Harmonics Mitigation
DEFF Research Database (Denmark)
Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede
2015-01-01
of power harmonics. The proposed optimal SHC is of hybrid structure: all recursive SHC modules with weighted gains are connected in parallel. It bridges the real “nk+-m order RC” and the complex “parallel structure RC”. Compared to other IMP based control solutions, it offers an optimal trade-off among...
Maintenance optimization in nuclear power plants through genetic algorithms
International Nuclear Information System (INIS)
Munoz, A.; Martorell, S.; Serradell, V.
1999-01-01
Establishing suitable scheduled maintenance tasks leads to optimizing the reliability of nuclear power plant safety systems. The articles addresses this subject, whilst endeavoring to tackle an overall optimization process for component availability and safety systems through the use of genetic algorithms. (Author) 20 refs
Stochastic Robust Mathematical Programming Model for Power System Optimization
Energy Technology Data Exchange (ETDEWEB)
Liu, Cong; Changhyeok, Lee; Haoyong, Chen; Mehrotra, Sanjay
2016-01-01
This paper presents a stochastic robust framework for two-stage power system optimization problems with uncertainty. The model optimizes the probabilistic expectation of different worst-case scenarios with ifferent uncertainty sets. A case study of unit commitment shows the effectiveness of the proposed model and algorithms.
Optimal sizing method for stand-alone photovoltaic power systems
Energy Technology Data Exchange (ETDEWEB)
Groumpos, P P; Papageorgiou, G
1987-01-01
The total life-cycle cost of stand-alone photovoltaic (SAPV) power systems is mathematically formulated. A new optimal sizing algorithm for the solar array and battery capacity is developed. The optimum value of a balancing parameter, M, for the optimal sizing of SAPV system components is derived. The proposed optimal sizing algorithm is used in an illustrative example, where a more economical life-cycle cost has bene obtained. The question of cost versus reliability is briefly discussed.
Optimal estimation and control in nuclear power plants
International Nuclear Information System (INIS)
Purviance, J.E.; Tylee, J.L.
1982-08-01
Optimal estimation and control theories offer the potential for more precise control and diagnosis of nuclear power plants. The important element of these theories is that a mathematical plant model is used in conjunction with the actual plant data to optimize some performance criteria. These criteria involve important plant variables and incorporate a sense of the desired plant performance. Several applications of optimal estimation and control to nuclear systems are discussed
Optimal control of wind power plants
Steinbuch, M.; Boer, de W.W.; Bosgra, O.H.; Peeters, S.A.W.M.; Ploeg, J.
1988-01-01
The control system design for a wind power plant is investigated. Both theoverall wind farm control and the individual wind turbine control effect thewind farm dynamic performance.For a wind turbine with a synchronous generator and rectifier/invertersystem a multivariable controller is designed.
Energy Technology Data Exchange (ETDEWEB)
Pratt, R.G.; Miller, J.D.
1997-09-01
The New York Power Authority (NYPA) and the New York City Housing Authority (NYCHA) are replacing refrigerators in New York City public housing with new, highly energy-efficient models over a five-year period. This report describes the analysis of the energy cost savings achieved through the replacement of 20,000 refrigerators in 1996, the first year of the NYPA/NYCHA program. The NYPA/NYCHA project serves as the lynchpin of a larger program designed to offer energy-efficient appliances to housing authorities across the country. The national program is a partnership between the U.S. Department of Energy (DOE) and the Consortium for Energy Efficiency (CEE). Starting with the 1997 refrigerator contract, this program invites other housing authorities to join NYPA in its volume purchase of energy-efficient refrigerators, at the same price and terms available to NYPA. Through these volume purchases, DOE`s ENERGY STAR{reg_sign} Partnerships program hopes to encourage appliance manufacturers to bring more efficient appliances to the market and to provide volume purchasers with the per-unit price savings of a bulk purchaser. DOE asked the Pacific Northwest National Laboratory (PNNL) to establish a protocol for evaluating the savings achieved with the NYPA refrigerators. That protocol is summarized in this report.
A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems
Directory of Open Access Journals (Sweden)
Giovanni Carabin
2017-12-01
Full Text Available In the last decades, increasing energy prices and growing environmental awareness have driven engineers and scientists to find new solutions for reducing energy consumption in manufacturing. Although many processes of a high energy consumption (e.g., chemical, heating, etc. are considered to have reached high levels of efficiency, this is not the case for many other industrial manufacturing activities. Indeed, this is the case for robotic and automatic systems, for which, in the past, the minimization of energy demand was not considered a design objective. The proper design and operation of industrial robots and automation systems represent a great opportunity for reducing energy consumption in the industry, for example, by the substitution with more efficient systems and the energy optimization of operation. This review paper classifies and analyses several methodologies and technologies that have been developed with the aim of providing a reference of existing methods, techniques and technologies for enhancing the energy performance of industrial robotic and mechatronic systems. Hardware and software methods, including several subcategories, are considered and compared, and emerging ideas and possible future perspectives are discussed.
Optimized control strategy for crowbarless solid state modular power supply
International Nuclear Information System (INIS)
Upadhyay, R.; Badapanda, M.K.; Tripathi, A.; Hannurkar, P.R.; Pithawa, C.K.
2009-01-01
Solid state modular power supply with series connected IGBT based power modules have been employed as high voltage bias power supply of klystron amplifier. Auxiliary compensation of full wave inverter bridge with ZVS/ZCS operations of all IGBTs over entire operating range is incorporated. An optimized control strategy has been adopted for this power supply needing no output filter, making this scheme crowbarless and is presented in this paper. DSP based fully digital control with same duty cycle for all power modules, have been incorporated for regulating this power supply along with adequate protection features. Input to this power supply is taken directly from 11 kV line and the input system is intentionally made 24 pulsed to reduce the input harmonics, improve the input power factor significantly, there by requiring no line filters. Various steps have been taken to increase the efficiency of major subsystems, so as to improve the overall efficiency of this power supply significantly. (author)
Optimal contracts for wind power producers in electricity markets
Bitar, E.
2010-12-01
This paper is focused on optimal contracts for an independent wind power producer in conventional electricity markets. Starting with a simple model of the uncertainty in the production of power from a wind turbine farm and a model for the electric energy market, we derive analytical expressions for optimal contract size and corresponding expected optimal profit. We also address problems involving overproduction penalties, cost of reserves, and utility of additional sensor information. We obtain analytical expressions for marginal profits from investing in local generation and energy storage. ©2010 IEEE.
DEFF Research Database (Denmark)
Liu, Chengxi; Qin, Nan; Bak, Claus Leth
2015-01-01
This paper proposes a hybrid optimization method to optimally control the voltage and reactive power with minimum power loss in transmission grid. This approach is used for the Danish automatic voltage control (AVC) system which is typically a non-linear non-convex problem mixed with both...
Optimal contracts for wind power producers in electricity markets
Bitar, E.; Giani, A.; Rajagopal, R.; Varagnolo, D.; Khargonekar, P.; Poolla, K.; Varaiya, P.
2010-01-01
This paper is focused on optimal contracts for an independent wind power producer in conventional electricity markets. Starting with a simple model of the uncertainty in the production of power from a wind turbine farm and a model for the electric
Optimal configuration of an integrated power and transport system
DEFF Research Database (Denmark)
Juul, Nina; Meibom, Peter
2011-01-01
optimal investments in both power plants and vehicle technologies is presented in this article. The model includes the interactions between the power system and the transport system including the competition between flexibility measures such as hydrogen storage in combination with electrolysis, heat...... storage in combination with heat pumps and heat boilers, and plug-in electric vehicles....
Direct Fuel Injector Power Drive System Optimization
2014-04-01
solenoid coil to create magnetic field in the stator. Then, the stator pulls the pintle to open the injector nozzle . This pintle movement occurs when the...that typically deal with power strategies to the injector solenoid coil. Numerical simulation codes for diesel injection systems were developed by...Laboratory) for providing the JP-8 test fuel. REFERENCES 1. Digesu, P. and Laforgia D., “ Diesel electro- injector : A numerical simulation code”. Journal of
Joint optimization of regional water-power systems
Pereira-Cardenal, Silvio J.; Mo, Birger; Gjelsvik, Anders; Riegels, Niels D.; Arnbjerg-Nielsen, Karsten; Bauer-Gottwein, Peter
2016-06-01
Energy and water resources systems are tightly coupled; energy is needed to deliver water and water is needed to extract or produce energy. Growing pressure on these resources has raised concerns about their long-term management and highlights the need to develop integrated solutions. A method for joint optimization of water and electric power systems was developed in order to identify methodologies to assess the broader interactions between water and energy systems. The proposed method is to include water users and power producers into an economic optimization problem that minimizes the cost of power production and maximizes the benefits of water allocation, subject to constraints from the power and hydrological systems. The method was tested on the Iberian Peninsula using simplified models of the seven major river basins and the power market. The optimization problem was successfully solved using stochastic dual dynamic programming. The results showed that current water allocation to hydropower producers in basins with high irrigation productivity, and to irrigation users in basins with high hydropower productivity was sub-optimal. Optimal allocation was achieved by managing reservoirs in very distinct ways, according to the local inflow, storage capacity, hydropower productivity, and irrigation demand and productivity. This highlights the importance of appropriately representing the water users' spatial distribution and marginal benefits and costs when allocating water resources optimally. The method can handle further spatial disaggregation and can be extended to include other aspects of the water-energy nexus.
Stochastic Optimization of Wind Turbine Power Factor Using Stochastic Model of Wind Power
DEFF Research Database (Denmark)
Chen, Peiyuan; Siano, Pierluigi; Bak-Jensen, Birgitte
2010-01-01
This paper proposes a stochastic optimization algorithm that aims to minimize the expectation of the system power losses by controlling wind turbine (WT) power factors. This objective of the optimization is subject to the probability constraints of bus voltage and line current requirements....... The optimization algorithm utilizes the stochastic models of wind power generation (WPG) and load demand to take into account their stochastic variation. The stochastic model of WPG is developed on the basis of a limited autoregressive integrated moving average (LARIMA) model by introducing a crosscorrelation...... structure to the LARIMA model. The proposed stochastic optimization is carried out on a 69-bus distribution system. Simulation results confirm that, under various combinations of WPG and load demand, the system power losses are considerably reduced with the optimal setting of WT power factor as compared...
Optimal Power Flow in Microgrids with Energy Storage
DEFF Research Database (Denmark)
Levron, Yoash; Guerrero, Josep M.; Beck, Yuval
2013-01-01
Energy storage may improve power management in microgrids that include renewable energy sources. The storage devices match energy generation to consumption, facilitating a smooth and robust energy balance within the microgrid. This paper addresses the optimal control of the microgrid’s energy...... storage devices. Stored energy is controlled to balance power generation of renewable sources to optimize overall power consumption at the microgrid point of common coupling. Recent works emphasize constraints imposed by the storage device itself, such as limited capacity and internal losses. However...
Optimal Parameter Selection of Power System Stabilizer using Genetic Algorithm
Energy Technology Data Exchange (ETDEWEB)
Chung, Hyeng Hwan; Chung, Dong Il; Chung, Mun Kyu [Dong-AUniversity (Korea); Wang, Yong Peel [Canterbury Univeristy (New Zealand)
1999-06-01
In this paper, it is suggested that the selection method of optimal parameter of power system stabilizer (PSS) with robustness in low frequency oscillation for power system using real variable elitism genetic algorithm (RVEGA). The optimal parameters were selected in the case of power system stabilizer with one lead compensator, and two lead compensator. Also, the frequency responses characteristics of PSS, the system eigenvalues criterion and the dynamic characteristics were considered in the normal load and the heavy load, which proved usefulness of RVEGA compare with Yu's compensator design theory. (author). 20 refs., 15 figs., 8 tabs.
Hybrid robust predictive optimization method of power system dispatch
Chandra, Ramu Sharat [Niskayuna, NY; Liu, Yan [Ballston Lake, NY; Bose, Sumit [Niskayuna, NY; de Bedout, Juan Manuel [West Glenville, NY
2011-08-02
A method of power system dispatch control solves power system dispatch problems by integrating a larger variety of generation, load and storage assets, including without limitation, combined heat and power (CHP) units, renewable generation with forecasting, controllable loads, electric, thermal and water energy storage. The method employs a predictive algorithm to dynamically schedule different assets in order to achieve global optimization and maintain the system normal operation.
Power Link Optimization for a Neurostimulator in Nasal Cavity
Directory of Open Access Journals (Sweden)
Seunghyun Lee
2017-01-01
Full Text Available This paper examines system optimization for wirelessly powering a small implant embedded in tissue. For a given small receiver in a multilayer tissue model, the transmitter is abstracted as a sheet of tangential current density for which the optimal distribution is analytically found. This proposes a new design methodology for wireless power transfer systems. That is, from the optimal current distribution, the maximum achievable efficiency is derived first. Next, various design parameters are determined to achieve the target efficiency. Based on this design methodology, a centimeter-sized neurostimulator inside the nasal cavity is demonstrated. For this centimeter-sized implant, the optimal distribution resembles that of a coil source and the optimal frequency is around 15 MHz. While the existing solution showed an efficiency of about 0.3 percent, the proposed system could enhance the efficiency fivefold.
Optimal power transaction matrix rescheduling under multilateral open access environment
International Nuclear Information System (INIS)
Moghaddam, M.P.; Raoofat, M.; Haghifam, M.R.
2004-01-01
This paper addresses a new concept for determining optimal transactions between different entities in a multilateral environment while benefits of both buyer and seller entities are taken into account with respect to the rules of the system. At the same time, constraints of the network are met, which leads to an optimal power flow problem. A modified power transaction matrix is proposed for modeling the environment. The optimization method in this paper is the continuation method, which is suited for complex situations of power system studies. This complexity will become more serious when dual interaction between financial and electrical subsystems of competitive power system are taken into account. The proposed approach is tested on a typical network with satisfactory results. (author)
A Hybrid Harmony Search Algorithm Approach for Optimal Power Flow
Directory of Open Access Journals (Sweden)
Mimoun YOUNES
2012-08-01
Full Text Available Optimal Power Flow (OPF is one of the main functions of Power system operation. It determines the optimal settings of generating units, bus voltage, transformer tap and shunt elements in Power System with the objective of minimizing total production costs or losses while the system is operating within its security limits. The aim of this paper is to propose a novel methodology (BCGAs-HSA that solves OPF including both active and reactive power dispatch It is based on combining the binary-coded genetic algorithm (BCGAs and the harmony search algorithm (HSA to determine the optimal global solution. This method was tested on the modified IEEE 30 bus test system. The results obtained by this method are compared with those obtained with BCGAs or HSA separately. The results show that the BCGAs-HSA approach can converge to the optimum solution with accuracy compared to those reported recently in the literature.
Energy and ancillary service dispatch through dynamic optimal power flow
International Nuclear Information System (INIS)
Costa, A.L.; Costa, A. Simoes
2007-01-01
This paper presents an approach based on dynamic optimal power flow (DOPF) to clear both energy and spinning reserve day-ahead markets. A competitive environment is assumed, where agents can offer active power for both demand supply and ancillary services. The DOPF jointly determines the optimal solutions for both energy dispatch and reserve allocation. A non-linear representation for the electrical network is employed, which is able to take transmission losses and power flow limits into account. An attractive feature of the proposed approach is that the final optimal solution will automatically meet physical constraints such as generating limits and ramp rate restrictions. In addition, the proposed framework allows the definition of multiple zones in the network for each time interval, in order to ensure a more adequate distribution of reserves throughout the power system. (author)
Optimized dispatch of wind farms with power control capability for power system restoration
DEFF Research Database (Denmark)
Xie, Yunyun; Liu, Changsheng; Wu, Qiuwei
2017-01-01
As the power control technology of wind farms develops, the output power of wind farms can be constant, which makes it possible for wind farms to participate in power system restoration. However, due to the uncertainty of wind energy, the actual output power can’t reach a constant dispatch power...... in all time intervals, resulting in uncertain power sags which may induce the frequency of the system being restored to go outside the security limits. Therefore, it is necessary to optimize the dispatch of wind farms participating in power system restoration. Considering that the probability...... distribution function (PDF) of transient power sags is hard to obtain, a robust optimization model is proposed in this paper, which can maximize the output power of wind farms participating in power system restoration. Simulation results demonstrate that the security constraints of the restored system can...
An extra power saving scheme for prolonging lifetime of mobile handset in the 4G mobile networks.
Chen, Jenhui; Tarn, Woei-Hwa; Lee, Jiann-Der
2014-01-01
In the fourth generation or next generation networks, services of non-real-time variable bit rate (NRT-VBR) and best effort (BE) will dominate over 85% of the total traffic in the networks. In this paper, we study the power saving mechanism of NRT-VBR and BE services for mobile handsets (MHs) to prolong their battery lifetime (i.e., the sustained operation duration) in the fourth generation networks. Because the priority of NRT-VBR and BE is lower than that of real-time VBR (RT-VBR) or guaranteed bit rate (GBR) services, we investigate an extended sleep mode for lower priority services (e.g., NRT-VBR and BE) in an MH to conserve the energy. The extended sleep mode is used when the MH wakes up from the sleep mode but it cannot obtain the bandwidth from base station (BS). The proposed mechanism, named extra power saving scheme (EPSS), uses the M/M/k/k Markovian queuing model to estimate the extended sleep duration to let MHs conserve their battery energy when the networks traffic is congested. To study the performance of EPSS, an accurate analysis model of energy is presented and validated by taking a series of simulations. Numerical experiments show that EPSS can achieve 43% extra energy conservation at most when downlink resource is saturated. We conclude that the energy of MHs can be conserved further by applying EPSS when the traffic load is saturated. The effect of energy saving becomes more obvious when the portion of NRT-VBR and BE services is greater than that of RT-VBR and GBR services.
DEFF Research Database (Denmark)
Zvingilaite, Erika
2013-01-01
. Furthermore, the results suggest that changes in the energy generation sector are the prime driver behind the reduction of environmental externalities of energy. Heat savings in buildings play only a small role under model assumptions. © 2012Elsevier Ltd. All rights reserved.......A substantial untapped energy saving potential rests in the building sector and is expected to play an important role in achieving reduction of environmental impacts of energy. In order to utilise this potential, effective policy measures need to be adopted to remove the existing barriers...... and create incentives. For that purpose, the cost effective energy saving options together with an optimal level of savings and expected environmental benefits have to be identified. The paper reports on a study that analyses these questions by including heat-saving measures in buildings into an energy...
Optimal energy management strategy for battery powered electric vehicles
International Nuclear Information System (INIS)
Xi, Jiaqi; Li, Mian; Xu, Min
2014-01-01
Highlights: • The power usage for battery-powered electrical vehicles with in-wheel motors is maximized. • The battery and motor dynamics are examined emphasized on the power conversion and utilization. • The optimal control strategy is derived and verified by simulations. • An analytic expression of the optimal operating point is obtained. - Abstract: Due to limited energy density of batteries, energy management has always played a critical role in improving the overall energy efficiency of electric vehicles. In this paper, a key issue within the energy management problem will be carefully tackled, i.e., maximizing the power usage of batteries for battery-powered electrical vehicles with in-wheel motors. To this end, the battery and motor dynamics will be thoroughly examined with particular emphasis on the power conversion and power utilization. The optimal control strategy will then be derived based on the analysis. One significant contribution of this work is that an analytic expression for the optimal operating point in terms of the component and environment parameters can be obtained. Owing to this finding, the derived control strategy is also rendered a simple structure for real-time implementation. Simulation results demonstrate that the proposed strategy works both adaptively and robustly under different driving scenarios
Directory of Open Access Journals (Sweden)
Leyzgold D.Yu.
2015-04-01
Full Text Available This article studies the problem of the transmission line conductor heating effect on the active power flows optimization in the local segment of industrial power supply. The purpose is to determine the optimal generation rating of the distributed power sources, in which the power flow values will correspond to the minimum active power losses in the power supply. The timeliness is the need to define the most appropriate rated power values of distributed sources which will be connected to current industrial power supply. Basing on the model of active power flow optimization, authors formulate the description of the nonlinear transportation problem considering the active power losses depending on the transmission line conductor heating. Authors proposed a new approach to the heating model parameters definition based on allowable current loads and nominal parameters of conductors as part of the optimization problem. Analysis of study results showed that, despite the relatively small active power losses reduction to the tune 0,45% due to accounting of the conductors heating effect for the present configuration of power supply, there are significant fluctuations in the required generation rating in nodes of the network to 9,32% within seasonal changes in the outer air temperature. This fact should be taken into account when selecting the optimum power of distributed generation systems, as exemplified by an arbitrary network configuration.
Optimization of passive low power wireless electromagnetic energy harvesters.
Nimo, Antwi; Grgić, Dario; Reindl, Leonhard M
2012-10-11
This work presents the optimization of antenna captured low power radio frequency (RF) to direct current (DC) power converters using Schottky diodes for powering remote wireless sensors. Linearized models using scattering parameters show that an antenna and a matched diode rectifier can be described as a form of coupled resonator with different individual resonator properties. The analytical models show that the maximum voltage gain of the coupled resonators is mainly related to the antenna, diode and load (remote sensor) resistances at matched conditions or resonance. The analytical models were verified with experimental results. Different passive wireless RF power harvesters offering high selectivity, broadband response and high voltage sensitivity are presented. Measured results show that with an optimal resistance of antenna and diode, it is possible to achieve high RF to DC voltage sensitivity of 0.5 V and efficiency of 20% at -30 dBm antenna input power. Additionally, a wireless harvester (rectenna) is built and tested for receiving range performance.
Optimizing the wireless power transfer over MIMO Channels
Wiedmann, Karsten; Weber, Tobias
2017-09-01
In this paper, the optimization of the power transfer over wireless channels having multiple-inputs and multiple-outputs (MIMO) is studied. Therefore, the transmitter, the receiver and the MIMO channel are modeled as multiports. The power transfer efficiency is described by a Rayleigh quotient, which is a function of the channel's scattering parameters and the incident waves from both transmitter and receiver side. This way, the power transfer efficiency can be maximized analytically by solving a generalized eigenvalue problem, which is deduced from the Rayleigh quotient. As a result, the maximum power transfer efficiency achievable over a given MIMO channel is obtained. This maximum can be used as a performance bound in order to benchmark wireless power transfer systems. Furthermore, the optimal operating point which achieves this maximum will be obtained. The optimal operating point will be described by the complex amplitudes of the optimal incident and reflected waves of the MIMO channel. This supports the design of the optimal transmitter and receiver multiports. The proposed method applies for arbitrary MIMO channels, taking transmitter-side and/or receiver-side cross-couplings in both near- and farfield scenarios into consideration. Special cases are briefly discussed in this paper in order to illustrate the method.
Optimizing the wireless power transfer over MIMO Channels
Directory of Open Access Journals (Sweden)
K. Wiedmann
2017-09-01
Full Text Available In this paper, the optimization of the power transfer over wireless channels having multiple-inputs and multiple-outputs (MIMO is studied. Therefore, the transmitter, the receiver and the MIMO channel are modeled as multiports. The power transfer efficiency is described by a Rayleigh quotient, which is a function of the channel's scattering parameters and the incident waves from both transmitter and receiver side. This way, the power transfer efficiency can be maximized analytically by solving a generalized eigenvalue problem, which is deduced from the Rayleigh quotient. As a result, the maximum power transfer efficiency achievable over a given MIMO channel is obtained. This maximum can be used as a performance bound in order to benchmark wireless power transfer systems. Furthermore, the optimal operating point which achieves this maximum will be obtained. The optimal operating point will be described by the complex amplitudes of the optimal incident and reflected waves of the MIMO channel. This supports the design of the optimal transmitter and receiver multiports. The proposed method applies for arbitrary MIMO channels, taking transmitter-side and/or receiver-side cross-couplings in both near- and farfield scenarios into consideration. Special cases are briefly discussed in this paper in order to illustrate the method.
Energy Technology Data Exchange (ETDEWEB)
Hansen, A D; Bindner, H [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Rebsdorf, A [Vestas Wind Systems A/S, Lem (Denmark)
1999-03-01
The paper summarises and describes the main results of a recently performed study of improving the transition between power optimization and power limitation for variable speed/variable pitch wind turbines. The results show that the capability of varying the generator speed also can be exploited in the transition stage to improve the quality of the generated power. (au)
International Nuclear Information System (INIS)
Zainuddin Abd Manan; Lim Fang Yee
2001-01-01
Combined heat and power (CHP) scheme, also known as cogeneration is widely accepted as a highly efficient energy saving measure, particularly in medium to large scale chemical process plants. To date, CHP application is well established in the developed countries. The advantage of a CHP scheme for a chemical plant is two-fold: (i) drastically cut down on the electricity bill from on-site power generation (ii) to save the fuel bills through recovery of the quality waste heat from power generation for process heating. In order to be effective, a CHP scheme must be placed at the right temperature level in the context of the overall process. Failure to do so might render a CHP venture worthless. This paper discusses the procedure for an effective implementation of a CHP scheme. An ethylbenzene process is used as a case study. A key visualization tool known as the grand composite curves is used to provide an overall picture of the process heat source and heat sink profiles. The grand composite curve, which is generated based on the first principles of Pinch Analysis enables the CHP scheme to be optimally placed within the overall process scenario. (Author)
Evaluation of the Optimal Connection of Power Transformers in the Substations of a Hospital
Directory of Open Access Journals (Sweden)
Carlos Javier Renedo
2018-02-01
Full Text Available Transformers are installed in power distribution systems to perform changes in supply voltage. Large consumers often have several transformers installed in parallel to ensure continuity of supply in the event of failure. These machines can achieve very high efficiency, but their efficiency is not constant since it depends on the power demanded at each time. Therefore, the level of efficiency that correspond to the operation of a specific transformer depends on two factors: machine technical characteristics and electrical load. In this work, the authors have proposed a methodology which shows the optimal number of transformers to be connected at each period in the substations of a large Spanish hospital, in order to achieve the maximum seasonal efficiency of these machines. The results of the energy saving are determined with respect to the current situation, in which all the transformers are permanently connected. On the other hand, the European Union has established a new regulation that sets the minimum energy efficiency requirements for new power transformers. This efficiency improvement is proposed to be applied gradually in two stages, a first limit came into force in 2015, while a more restrictive approach will appear in the year 2021. This work has also studied the potential energy savings that would occur when the substations of the hospital have more efficient transformers complying with the new European Regulation 548/2014.
Optimal Operation of Plug-In Electric Vehicles in Power Systems with High Wind Power Penetrations
DEFF Research Database (Denmark)
Hu, Weihao; Su, Chi; Chen, Zhe
2013-01-01
in the power systems with high wind power penetrations. In this paper, the integration of plug-in electric vehicles in the power systems with high wind power penetrations is proposed and discussed. Optimal operation strategies of PEV in the spot market are proposed in order to decrease the energy cost for PEV......The Danish power system has a large penetration of wind power. The wind fluctuation causes a high variation in the power generation, which must be balanced by other sources. The battery storage based Plug-In Electric Vehicles (PEV) may be a possible solution to balance the wind power variations...... owners. Furthermore, the application of battery storage based aggregated PEV is analyzed as a regulation services provider in the power system with high wind power penetrations. The western Danish power system where the total share of annual wind power production is more than 27% of the electrical energy...
Optimal dispatch strategy for the agile virtual power plant
DEFF Research Database (Denmark)
Petersen, Mette Højgaard; Bendtsen, Jan Dimon; Stoustrup, Jakob
2012-01-01
The introduction of large ratios of renewable energy into the existing power system is complicated by the inherent variability of production technologies, which harvest energy from wind, sun and waves. Fluctuations of renewable power production can be predicted to some extent, but the assumption...... of perfect prediction is unrealistic. This paper therefore introduces the Agile Virtual Power Plant. The Agile Virtual Power Plant assumes that the base load production planning based on best available knowledge is already given, so imbalances cannot be predicted. Consequently the Agile Virtual Power Plant...... attempts to preserve maneuverability (stay agile) rather than optimize performance according to predictions. In this paper the imbalance compensation problem for an Agile Virtual Power Plant is formulated. It is proved formally, that when local units are power and energy constrained integrators a dispatch...
Eccli, Eugene; And Others
This publication is a collection of inexpensive energy saving tips and home improvements for home owners, particularly in low-income areas or in older homes. Section titles are: (1) Keeping Warm; (2) Getting Heat Where You Need It; (3) Using the Sun; (4) Furnaces, Stoves, and Fireplaces; (5) Insulation and Other Energy Needs; (6) Do-It-Yourself…
Saving of drinking water in cooling system at Aq aba Thermal Power Station
International Nuclear Information System (INIS)
Al-Nsour, A.F.
2001-01-01
This paper discussing a new modification, design and implementation to the existing cooling water system of boiler drum continuous blow down water at Aq aba Thermal Power Stations to eliminate drinking water consumption as a coolant medium
Mclyman, W. T. (Inventor)
1981-01-01
In a push-pull converter, switching transistors are protected from peak power stresses by a separate snubber circuit in parallel with each comprising a capacitor and an inductor in series, and a diode in parallel with the inductor. The diode is connected to conduct current of the same polarity as the base-emitter juction of the transistor so that energy stored in the capacitor while the transistor is switched off, to protect it against peak power stress, discharges through the inductor when the transistor is turned on, and after the capacitor is discharges through the diode. To return this energy to the power supply, or to utilize this energy in some external circuit, the inductor may be replaced by a transformer having its secondary winding connected to the power supply or to the external circuit.
Modified artificial bee colony algorithm for reactive power optimization
Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani
2015-05-01
Bio-inspired algorithms (BIAs) implemented to solve various optimization problems have shown promising results which are very important in this severely complex real-world. Artificial Bee Colony (ABC) algorithm, a kind of BIAs has demonstrated tremendous results as compared to other optimization algorithms. This paper presents a new modified ABC algorithm referred to as JA-ABC3 with the aim to enhance convergence speed and avoid premature convergence. The proposed algorithm has been simulated on ten commonly used benchmarks functions. Its performance has also been compared with other existing ABC variants. To justify its robust applicability, the proposed algorithm has been tested to solve Reactive Power Optimization problem. The results have shown that the proposed algorithm has superior performance to other existing ABC variants e.g. GABC, BABC1, BABC2, BsfABC dan IABC in terms of convergence speed. Furthermore, the proposed algorithm has also demonstrated excellence performance in solving Reactive Power Optimization problem.
Optimal Power Constrained Distributed Detection over a Noisy Multiaccess Channel
Directory of Open Access Journals (Sweden)
Zhiwen Hu
2015-01-01
Full Text Available The problem of optimal power constrained distributed detection over a noisy multiaccess channel (MAC is addressed. Under local power constraints, we define the transformation function for sensor to realize the mapping from local decision to transmitted waveform. The deflection coefficient maximization (DCM is used to optimize the performance of power constrained fusion system. Using optimality conditions, we derive the closed-form solution to the considered problem. Monte Carlo simulations are carried out to evaluate the performance of the proposed new method. Simulation results show that the proposed method could significantly improve the detection performance of the fusion system with low signal-to-noise ratio (SNR. We also show that the proposed new method has a robust detection performance for broad SNR region.
Dynamic ADMM for Real-time Optimal Power Flow: Preprint
Energy Technology Data Exchange (ETDEWEB)
Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2018-02-23
This paper considers distribution networks featuring distributed energy resources (DERs), and develops a dynamic optimization method to maximize given operational objectives in real time while adhering to relevant network constraints. The design of the dynamic algorithm is based on suitable linearizations of the AC power flow equations, and it leverages the so-called alternating direction method of multipliers (ADMM). The steps of the ADMM, however, are suitably modified to accommodate appropriate measurements from the distribution network and the DERs. With the aid of these measurements, the resultant algorithm can enforce given operational constraints in spite of inaccuracies in the representation of the AC power flows, and it avoids ubiquitous metering to gather the state of non-controllable resources. Optimality and convergence of the propose algorithm are established in terms of tracking of the solution of a convex surrogate of the AC optimal power flow problem.
Optimal pole shifting controller for interconnected power system
International Nuclear Information System (INIS)
Yousef, Ali M.; Kassem, Ahmed M.
2011-01-01
Research highlights: → Mathematical model represents a power system which consists of synchronous machine connected to infinite bus through transmission line. → Power system stabilizer was designed based on optimal pole shifting controller. → The system performances was tested through load disturbances at different operating conditions. → The system performance with the proposed optimal pole shifting controller is compared with the conventional pole placement controller. → The digital simulation results indicated that the proposed controller has a superior performance. -- Abstract: Power system stabilizer based on optimal pole shifting is proposed. An approach for shifting the real parts of the open-loop poles to any desired positions while preserving the imaginary parts is presented. In each step of this approach, it is required to solve a first-order or a second-order linear matrix Lyapunov equation for shifting one real pole or two complex conjugate poles, respectively. This presented method yields a solution, which is optimal with respect to a quadratic performance index. The attractive feature of this method is that it enables solutions of the complex problem to be easily found without solving any non-linear algebraic Riccati equation. The present power system stabilizer is based on Riccati equation approach. The control law depends on finding the feedback gain matrix, and then the control signal is synthesized by multiplying the state variables of the power system with determined gain matrix. The gain matrix is calculated one time only, and it works over wide range of operating conditions. To validate the power of the proposed PSS, a linearized model of a simple power system consisted of a single synchronous machine connected to infinite bus bar through transmission line is simulated. The studied power system is subjected to various operating points and power system parameters changes.
Optimal pole shifting controller for interconnected power system
Energy Technology Data Exchange (ETDEWEB)
Yousef, Ali M., E-mail: drali_yousef@yahoo.co [Electrical Eng. Dept., Faculty of Engineering, Assiut University (Egypt); Kassem, Ahmed M., E-mail: kassem_ahmed53@hotmail.co [Control Technology Dep., Industrial Education College, Beni-Suef University (Egypt)
2011-05-15
Research highlights: {yields} Mathematical model represents a power system which consists of synchronous machine connected to infinite bus through transmission line. {yields} Power system stabilizer was designed based on optimal pole shifting controller. {yields} The system performances was tested through load disturbances at different operating conditions. {yields} The system performance with the proposed optimal pole shifting controller is compared with the conventional pole placement controller. {yields} The digital simulation results indicated that the proposed controller has a superior performance. -- Abstract: Power system stabilizer based on optimal pole shifting is proposed. An approach for shifting the real parts of the open-loop poles to any desired positions while preserving the imaginary parts is presented. In each step of this approach, it is required to solve a first-order or a second-order linear matrix Lyapunov equation for shifting one real pole or two complex conjugate poles, respectively. This presented method yields a solution, which is optimal with respect to a quadratic performance index. The attractive feature of this method is that it enables solutions of the complex problem to be easily found without solving any non-linear algebraic Riccati equation. The present power system stabilizer is based on Riccati equation approach. The control law depends on finding the feedback gain matrix, and then the control signal is synthesized by multiplying the state variables of the power system with determined gain matrix. The gain matrix is calculated one time only, and it works over wide range of operating conditions. To validate the power of the proposed PSS, a linearized model of a simple power system consisted of a single synchronous machine connected to infinite bus bar through transmission line is simulated. The studied power system is subjected to various operating points and power system parameters changes.
Generating optimized stochastic power management strategies for electric car components
Energy Technology Data Exchange (ETDEWEB)
Fruth, Matthias [TraceTronic GmbH, Dresden (Germany); Bastian, Steve [Technische Univ. Dresden (Germany)
2012-11-01
With the increasing prevalence of electric vehicles, reducing the power consumption of car components becomes a necessity. For the example of a novel traffic-light assistance system, which makes speed recommendations based on the expected length of red-light phases, power-management strategies are used to control under which conditions radio communication, positioning systems and other components are switched to low-power (e.g. sleep) or high-power (e.g. idle/busy) states. We apply dynamic power management, an optimization technique well-known from other domains, in order to compute energy-optimal power-management strategies, sometimes resulting in these strategies being stochastic. On the example of the traffic-light assistant, we present a MATLAB/Simulink-implemented framework for the generation, simulation and formal analysis of optimized power-management strategies, which is based on this technique. We study capabilities and limitations of this approach and sketch further applications in the automotive domain. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Valer Negrete, Adrian [Programa de Ahorro de Energia del Sector Electrico (PAESE), Comision Federal de Electricidad (Mexico)
2003-07-01
Within the Programs of Energy Saving it is fundamental the search and application of new technologies, with which this saving can be obtained, selected with base in their technical characteristics that allow to reduce to the consumptions and demands of power, without damaging the electric networks nor the transformers of the Comision Federal de Electricidad. It is important that the investments which are made count on attractive periods of capital recovery, in comparison with the useful life of the product, reason why the knowledge and price of the new technologies will be parameters to consider in an important manner, creating the need of conducting tests that verify the veracity of the information of the supplier, resulting in certain cases, the change of design of these technologies, so that thus they fulfill the engaged characteristics. This paper indicates the characteristics that the new saving technologies of electrical energy must fulfill and the tests and parameters to consider their evaluation. [Spanish] Dentro de los Programas de Ahorro de Energia es fundamental la busqueda y aplicacion de nuevas tecnologias, con las que se pueda obtener dicho ahorro, seleccionadas con base en sus caracteristicas tecnicas que permitan reducir los consumos y demandas de potencia, sin danar las redes ni transformadores de la Comision Federal de Electricidad. Es importante que las inversiones que se realicen cuenten con periodos de recuperacion de capital atractivos, comparados con la vida util del producto, por lo que el conocimiento y precio de las nuevas tecnologias seran parametros a considerar de manera importante, creandose la necesidad de realizar pruebas que verifiquen la veracidad de la informacion del proveedor, resultando en determinados casos, el cambio de diseno de dichas tecnologias, para que asi cumplan las caracteristicas prometidas. Este trabajo indica las caracteristicas que deben cumplir las nuevas tecnologias ahorradoras de energia electrica y las
PSO Algorithm for an Optimal Power Controller in a Microgrid
Al-Saedi, W.; Lachowicz, S.; Habibi, D.; Bass, O.
2017-07-01
This paper presents the Particle Swarm Optimization (PSO) algorithm to improve the quality of the power supply in a microgrid. This algorithm is proposed for a real-time selftuning method that used in a power controller for an inverter based Distributed Generation (DG) unit. In such system, the voltage and frequency are the main control objectives, particularly when the microgrid is islanded or during load change. In this work, the PSO algorithm is implemented to find the optimal controller parameters to satisfy the control objectives. The results show high performance of the applied PSO algorithm of regulating the microgrid voltage and frequency.
Resource-based optimization of electric power production (in Iran)
International Nuclear Information System (INIS)
Sadeghzadeh, Mohammad
1999-01-01
This paper is about electric power production optimization and chiefly discusses on the types of resources available in Iran. The modeling has been based on the marginal cost of different energy resources and types of technologies used. the computed costs are the basic standards for optimization of the production system of energy. the costs associated with environmental pollution and also pollution control are considered. the present paper also studied gas fossil fuel, hydro, nuclear, renewable and co-generation of heat and power. The results are discussed and reported at the last of the paper
Energy Technology Data Exchange (ETDEWEB)
Lindegger, M.; Kreuzer, H.H.; Lischer, G.
2005-10-15
This annual report for the Swiss Federal Office of Energy (SFOE) takes a look at the results of the second phase of a project concerning the development of integrated energy-saving electrical motors in the power range less than one kilowatt. The search for industrial partners is commented on and the publishing of an initial functional prototype on the Internet is mentioned. Participation at various fairs and the publication of articles in the technical press are mentioned. Further work on the motor is described, as is development work done on the drive electronics and the associated software. Further work planned is described.
DEFF Research Database (Denmark)
Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte
2014-01-01
Consumers may decide to modify the profile of their demand from high price periods to low price periods in order to reduce their electricity costs. This optimal load response to electricity prices for demand side management generates different load profiles and provides an opportunity to achieve...... power loss minimization in distribution systems. In this paper, a new method to achieve power loss minimization in distribution systems by using a price signal to guide the demand side management is proposed. A fuzzy adaptive particle swarm optimization (FAPSO) is used as a tool for the power loss...
Optimal power flow management for distributed energy resources with batteries
International Nuclear Information System (INIS)
Tazvinga, Henerica; Zhu, Bing; Xia, Xiaohua
2015-01-01
Highlights: • A PV-diesel-battery hybrid system is proposed. • Model minimizes fuel and battery wear costs. • Power flows are analysed in a 24-h period. • Results provide a practical platform for decision making. - Abstract: This paper presents an optimal energy management model of a solar photovoltaic-diesel-battery hybrid power supply system for off-grid applications. The aim is to meet the load demand completely while satisfying the system constraints. The proposed model minimizes fuel and battery wear costs and finds the optimal power flow, taking into account photovoltaic power availability, battery bank state of charge and load power demand. The optimal solutions are compared for cases when the objectives are weighted equally and when a larger weight is assigned to battery wear. A considerable increase in system operational cost is observed in the latter case owing to the increased usage of the diesel generator. The results are important for decision makers, as they depict the optimal decisions considered in the presence of trade-offs between conflicting objectives
Resource-Saving Cleaning Technologies for Power Plant Waste-Water Cooling Ponds
Directory of Open Access Journals (Sweden)
Zakonnova Lyudmila
2017-01-01
Full Text Available One of the frequently encountered problems of power plant small cooling ponds is rapid eutrophication and related intensified development of phytoplankton (“hyperflow” and overgrowing of ponds by higher aquatic vegetation. As a result of hyper-flowering, an enormous amount of detritus settles on the condenser tubes, reducing the efficiency of the power plant operation. The development of higher aquatic vegetation contributes to the appearing of the shoals. As a result the volume, area and other characteristics of the cooling ponds are getting changed. The article describes the environmental problems of small manmade ponds of power plants and coal mines in mining regions. Two approaches to the problem of eutrophication are considered: technological and ecological. The negative effects of herbicides application to aquatic organisms are experimentally proved. An ecological approach to solving the problem by fish-land reclamation method is shown.
Optimal Water-Power Flow Problem: Formulation and Distributed Optimal Solution
Energy Technology Data Exchange (ETDEWEB)
Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zamzam, Admed S. [University of Minnesota; Sidiropoulos, Nicholas D. [University of Minnesota; Taylor, Josh A. [University of Toronto
2018-01-12
This paper formalizes an optimal water-power flow (OWPF) problem to optimize the use of controllable assets across power and water systems while accounting for the couplings between the two infrastructures. Tanks and pumps are optimally managed to satisfy water demand while improving power grid operations; {for the power network, an AC optimal power flow formulation is augmented to accommodate the controllability of water pumps.} Unfortunately, the physics governing the operation of the two infrastructures and coupling constraints lead to a nonconvex (and, in fact, NP-hard) problem; however, after reformulating OWPF as a nonconvex, quadratically-constrained quadratic problem, a feasible point pursuit-successive convex approximation approach is used to identify feasible and optimal solutions. In addition, a distributed solver based on the alternating direction method of multipliers enables water and power operators to pursue individual objectives while respecting the couplings between the two networks. The merits of the proposed approach are demonstrated for the case of a distribution feeder coupled with a municipal water distribution network.
Heuristic Optimization for the Discrete Virtual Power Plant Dispatch Problem
DEFF Research Database (Denmark)
Petersen, Mette Kirschmeyer; Hansen, Lars Henrik; Bendtsen, Jan Dimon
2014-01-01
We consider a Virtual Power Plant, which is given the task of dispatching a fluctuating power supply to a portfolio of flexible consumers. The flexible consumers are modeled as discrete batch processes, and the associated optimization problem is denoted the Discrete Virtual Power Plant Dispatch...... Problem. First NP-completeness of the Discrete Virtual Power Plant Dispatch Problem is proved formally. We then proceed to develop tailored versions of the meta-heuristic algorithms Hill Climber and Greedy Randomized Adaptive Search Procedure (GRASP). The algorithms are tuned and tested on portfolios...... of varying sizes. We find that all the tailored algorithms perform satisfactorily in the sense that they are able to find sub-optimal, but usable, solutions to very large problems (on the order of 10 5 units) at computation times on the scale of just 10 seconds, which is far beyond the capabilities...
Optimization of the decontamination in EDF PWR power plants
International Nuclear Information System (INIS)
Gosset, P.; Dupin, M.; Buisine, D.; Buet, J.F.; Brunel, V.
2002-01-01
The optimisation of decontamination in EDF PWR power plants is the result of a permanent collaborative work between the plant operators, the subcontractors, central services of nuclear power division of EDF. This collaborative work enables the saving of all the feedback experience. The main operations carried out on nuclear sites like mechanical decontamination of valves, use of the ''EMMAC'' process on big components (replacement of steam generator, hydraulic parts of the reactor coolant pumps), use of foam on pools walls and divers in highly contaminated pools have been discussed. This paper shows that the choice of decontamination processes is very dependant on the components, on the dose rate reduction to be aimed and on the possibility to treat the waste on site. (authors)
Optimized multi area AGC simulation in restructured power systems
International Nuclear Information System (INIS)
Bhatt, Praghnesh; Roy, Ranjit; Ghoshal, S.P.
2010-01-01
In this paper, the traditional automatic generation control loop with modifications is incorporated for simulating automatic generation control (AGC) in restructured power system. Federal energy regulatory commission (FERC) encourages an open market system for price based operation. FERC has issued a notice for proposed rulemaking of various ancillary services. One of these ancillary services is load following with frequency control which comes broadly under Automatic Generation Control in deregulated regime. The concept of DISCO participation matrix is used to simulate the bilateral contracts in the three areas and four area diagrams. Hybrid particle swarm optimization is used to obtain optimal gain parameters for optimal transient performance. (author)
Power Saving Scheduling Scheme for Internet of Things over LTE/LTE-Advanced Networks
Kuo, Yen-Wei; Chou, Li-Der
2015-01-01
The devices of Internet of Things (IoT) will grow rapidly in the near future, and the power consumption and radio spectrum management will become the most critical issues in the IoT networks. Long Term Evolution (LTE) technology will become a promising technology used in IoT networks due to its flat architecture, all-IP network, and greater spectrum efficiency. The 3rd Generation Partnership Project (3GPP) specified the Discontinuous Reception (DRX) to reduce device’s power consumption. Howev...
DEFF Research Database (Denmark)
Li, Qingnan; Andersen, Michael A. E.; Thomsen, Ole Cornelius
2011-01-01
Nowadays, efficiency and power density are the most important issues for Power Factor Correction (PFC) converters development. However, it is a challenge to reach both high efficiency and power density in a system at the same time. In this paper, taking a Bridgeless PFC (BPFC) as an example......, a useful compromise between efficiency and power density of the Boost inductors on 3.2kW is achieved using an optimized design procedure. The experimental verifications based on the optimized inductor are carried out from 300W to 3.2kW at 220Vac input....
Power saving control for the mobile DVB-H receivers based on H.264/SVC standard
DEFF Research Database (Denmark)
Belyaev, Evgeny; Grinko, Vitaly; Ukhanova, Ann
2009-01-01
This paper discusses the utilization of scalable extension of H.264/AVC standard in digital video broadcasting for handheld devices. In this area the problem of mobile receiver power consumption is critically important. This paper amplifies the well-known idea of the time-slicing and allows...
Linear Programming Approaches for Power Savings in Software-defined Networks
Moghaddam, F.A.; Grosso, P.
2016-01-01
Software-defined networks have been proposed as a viable solution to decrease the power consumption of the networking component in data center networks. Still the question remains on which scheduling algorithms are most suited to achieve this goal. We propose 4 different linear programming
Optimization of power generation from shrouded wind turbines
Energy Technology Data Exchange (ETDEWEB)
Foote, Tudor; Agarwal, Ramesh [Department of Mechanical Engineering and Materials Science, Washington University in St. Louis (United States)
2013-07-01
In past several years, several studies have shown that the shrouded wind turbines can generate greater power compared to bare turbines. The objective of this study is to determine the potential of shrouded wind turbines for increased power generation by conducting numerical simulations. An analytical/computational study is performed by employing the well-known commercial Computational Fluid Dynamics (CFD) software FLUENT. An actuator disc model is used to model the turbine. The incompressible Navier-Stokes equations and a two equation realizable {kappa}-{epsilon} model are employed in the calculations. The power coefficient Cp and generated power are calculated for a large number of cases for horizontal axis wind turbines (HAWT) of various diameters and wind speeds for both bare and shrouded turbines. The design of the shroud is optimized by employing a single objective genetic algorithm; the objective being the maximization of the power coefficient Cp. It was found that the shroud indeed increases the Cp beyond the Betz’s limit significantly and as a result the generated power; this effect is consistent with that found in the recent literature that the shrouded wind-turbines can generate greater power than the bare turbines. The optimized shape of the shroud or diffuser further increases the generated power and Cp.
Generation of Optimal Basis Functions for Reconstruction of Power Distribution
Energy Technology Data Exchange (ETDEWEB)
Park, Moonghu [Sejong Univ., Seoul (Korea, Republic of)
2014-05-15
This study proposes GMDH to find not only the best functional form but also the optimal parameters those describe the power distribution most accurately. A total of 1,060 cases of axially 1-dimensional core power distributions of 20-nodes are generated by 3-dimensional core analysis code covering BOL to EOL core burnup histories to validate the method. Axially five-point box powers at in-core detectors are considered as measurements. The reconstructed axial power shapes using GMDH method are compared to the reference power shapes. The results show that the proposed method is very robust and accurate compared with spline fitting method. It is shown that the GMDH analysis can give optimal basis functions for core power shape reconstruction. The in-core measurements are the 5 detector snapshots and the 20-node power distribution is successfully reconstructed. The effectiveness of the method is demonstrated by comparing the results of spline fitting for BOL, saddle and top-skewed power shapes.
International Nuclear Information System (INIS)
Glasgo, Brock; Azevedo, Inês Lima; Hendrickson, Chris
2016-01-01
Highlights: • DC distribution systems are analyzed using monitored appliance and solar PV data. • DC-distributed PV energy generates savings under real-world load and solar profiles. • Savings from direct-DC are generally not cost-effective in current markets. • Non-technical hurdles remain before DC can be widely adopted in US homes. - Abstract: Advances in semiconductor-based power electronics and growing direct current loads in buildings have led researchers to reconsider whether buildings should be wired with DC circuits to reduce power conversions and facilitate a transition to efficient DC appliances. The feasibility, energy savings, and economics of such systems have been assessed and proven in data centers and commercial buildings, but the outcomes are still uncertain for the residential sector. In this work, we assess the technical and economic feasibility of DC circuits using data for 120 traditionally-wired AC homes in Austin, Texas to understand the effect of highly variable demand profiles on DC-powered residences, using appliance-level use and solar generation data, and performing a Monte Carlo simulation to quantify costs and benefits. Results show site energy savings between 9% and 20% when solar PV is distributed to all home appliances. When battery storage for excess solar energy is considered, these savings increase to 14–25%. At present DC equipment prices, converting all equipment to DC causes levelized annual costs of electricity to homeowners to roughly double. However, by converting only homes’ air conditioning condensing units to DC, the costs of direct-DC are greatly reduced and home site energy savings of 7–16% are generated. In addition to quantifying savings, we find major nontechnical barriers to implementing direct-DC in homes. These include a lack of standards for such systems, a relatively small market for DC appliances and components, utility programs designed for AC power, and a workforce unfamiliar with DC
Optimizing efficiency on conventional transformer based low power AC/DC standby power supplies
DEFF Research Database (Denmark)
Nielsen, Nils
2004-01-01
This article describes the research results for simple and cheap methods to reduce the idle- and load-losses in very low power conventional transformer based power supplies intended for standby usage. In this case "very low power" means 50 Hz/230 V-AC to 5 V-DC@1 W. The efficiency is measured...... on two common power supply topologies designed for this power level. The two described topologies uses either a series (or linear) or a buck regulation approach. Common to the test power supplies is they either are using a standard cheap off-the-shelf transformer, or one, which are loss optimized by very...
Techno-economic optimization for the design of solar chimney power plants
International Nuclear Information System (INIS)
Ali, Babkir
2017-01-01
Highlights: • Chimney height and collector area of different designs were optimized. • Simple actual and minimum payback periods were developed. • Comparative assessment was conducted for different designs configuration. • Effects of uncertain parameters on the payback period were studied. - Abstract: This paper aims to propose a methodology for optimization of solar chimney power plants taking into account the techno-economic parameters. The indicator used for optimization is the comparison between the actual achieved simple payback period for the design and the minimum possible (optimum) simple payback period as a reference. An optimization model was executed for different twelve designs in the range 5–200 MW to cover reinforced concrete chimney, sloped collector, and floating chimney. The height of the chimney was optimized and the associated collector area was calculated accordingly. Relationships between payback periods, electricity price, and the peak power capacity of each power plant were developed. The resulted payback periods for the floating chimney power plants were the shortest compared to the other studied designs. For a solar chimney power plant with 100 MW at electricity price 0.10 USD/kWh, the simple payback period for the reference case was 4.29 years for floating chimney design compared to 23.47 and 16.88 years for reinforced concrete chimney and sloped collector design, respectively. After design optimization for 100 MW power plant of each of reinforced concrete, sloped collector, and floating chimney, a save of 19.63, 2.22, and 2.24 million USD, respectively from the initial cost of the reference case is achieved. Sensitivity analysis was conducted in this study to evaluate the impacts of varied running cost, solar radiation, and electricity price on the payback periods of solar chimney power plant. Floating chimney design is still performing after applying the highest ratio of annual running cost to the annual revenue. The
Optimization in the scale of nuclear power generation and the economy of nuclear power
International Nuclear Information System (INIS)
Suzuki, Toshiharu
1983-01-01
In the not too distant future, the economy of nuclear power will have to be restudied. Various conditions and circumstances supporting this economy of nuclear power tend to change, such as the decrease in power demand and supply, the diversification in base load supply sources, etc. The fragility in the economic advantage of nuclear power may thus be revealed. In the above connection, on the basis of the future outlook of the scale of nuclear power generation, that is, the further reduction of the current nuclear power program, and of the corresponding supply and demand of nuclear fuel cycle quantities, the aspect of the economic advantage of nuclear power was examined, for the purpose of optimizing the future scale of nuclear power generation (the downward revision of the scale, the establishment of the schedule of nuclear fuel cycle the stagnation of power demand and nuclear power generation costs). (Mori, K.)
Kwon, Hyuk Ju; Yeon, Sang Hun; Lee, Keum Ho; Lee, Kwang Ho
2018-02-01
As various studies focusing on building energy saving have been continuously conducted, studies utilizing renewable energy sources, instead of fossil fuel, are needed. In particular, studies regarding solar energy are being carried out in the field of building science; in order to utilize such solar energy effectively, solar radiation being brought into the indoors should be acquired and blocked properly. Blinds are a typical solar radiation control device that is capable of controlling indoor thermal and light environments. However, slat-type blinds are manually controlled, giving a negative effect on building energy saving. In this regard, studies regarding the automatic control of slat-type blinds have been carried out for the last couple of decades. Therefore, this study aims to provide preliminary data for optimal control research through the controlling of slat angle in slat-type blinds by comprehensively considering various input variables. The window area ratio and orientation were selected as input variables. It was found that an optimal control algorithm was different among each window-to-wall ratio and window orientation. In addition, through comparing and analyzing the building energy saving performance for each condition by applying the developed algorithms to simulations, up to 20.7 % energy saving was shown in the cooling period and up to 12.3 % energy saving was shown in the heating period. In addition, building energy saving effect was greater as the window area ratio increased given the same orientation, and the effects of window-to-wall ratio in the cooling period were higher than those of window-to-wall ratio in the heating period.
Saving energy and money at choice of power transformers, v. 16(63)
International Nuclear Information System (INIS)
Jankoski, Dimitar
2008-01-01
When power transformers work at regular conditions, besides they exert theirs principal function, they constantly spend electrical energy that is, always work with losses. Depending od performances, sometimes those losses can be drastically different, although the transformers can equal power and some voltages of transformation. Considering that the loss of energy has its own price, a dilemma whether it is better economic reason to purchase new expensive transformer with smaller losses or one cheaper with more losses during its work-comes out. This paper analysis such case. The presented access can usefully serve in practice, in making the right decision in replacing the old transformer with the new one, or choosing the new transformer. (Author)
Saving energy and money at choice of power transformers, v. 16(62)
International Nuclear Information System (INIS)
Jankoski, Dimitar
2008-01-01
When power transformers work at regular conditions, besides they exert theirs principal function, they constantly spend electrical energy that is, always work with losses. Depending od performances, sometimes those losses can be drastically different, although the transformers can equal power and some voltages of transformation. Considering that the loss of energy has its own price, a dilemma whether it is better economic reason to purchase new expensive transformer with smaller losses or one cheaper with more losses during its work-comes out. This paper analysis such case. The presented access can usefully serve in practice, in making the right decision in replacing the old transformer with the new one, or choosing the new transformer. (Author)
Energy Technology Data Exchange (ETDEWEB)
Nipkow, J.
2005-07-01
This final report for the Swiss Federal Office of Energy (SFOE) reviews the results of a study made on the electricity consumption of lifts, which estimates that around 0.5% of Swiss power consumption is caused by lift installations. The results of measurements made on 33 various lift installations and their power consumption are presented. The SIA 380/4 model used to determine energy consumption on the basis of the number of movements is described. Stand-by and lighting consumption is examined, which, according to the authors' conclusions, offer considerable room for improvement, especially for lifts in residential buildings. A further significant potential for improvement is also noted which can be achieved when renewing older systems. The avoidance of inefficient concepts by the use of guidelines for architects, planners and customers is recommended.
Energy and Resource-Saving Sources of Energy in Small Power Engineering of Siberia
Directory of Open Access Journals (Sweden)
Baranova Marina
2017-01-01
Full Text Available The sustainable development of distant areas of Siberia is associated with the structures of energy demand and supply, the implementation and promotion of the process of environmentally safe restructuring of the energy supply system. It has been established that suspension coal fuels derived from brown coal, coal mining, coal processing wastes can be used as fuel. The results of experimental and industrial boilers on suspension water coal fuel are presented. The designs of vortex combustion chambers of various powers are developed and tested. The possibility of using coal-enrichment wastes and substandard coals for the production of manure-coal fuel briquettes was studied. It is shown that the strength and thermal power characteristics of briquettes depend on the moisture content and degree of metamorphism of the raw materials. The most effective percentage of the solid phase and manure, as a binder, was determined.
Reactive power dispatch considering voltage stability with seeker optimization algorithm
Energy Technology Data Exchange (ETDEWEB)
Dai, Chaohua; Chen, Weirong; Zhang, Xuexia [The School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhu, Yunfang [Department of Computer and Communication Engineering, E' mei Campus, Southwest Jiaotong University, E' mei 614202 (China)
2009-10-15
Optimal reactive power dispatch (ORPD) has a growing impact on secure and economical operation of power systems. This issue is well known as a non-linear, multi-modal and multi-objective optimization problem where global optimization techniques are required in order to avoid local minima. In the last decades, computation intelligence-based techniques such as genetic algorithms (GAs), differential evolution (DE) algorithms and particle swarm optimization (PSO) algorithms, etc., have often been used for this aim. In this work, a seeker optimization algorithm (SOA) based method is proposed for ORPD considering static voltage stability and voltage deviation. The SOA is based on the concept of simulating the act of human searching where search direction is based on the empirical gradient by evaluating the response to the position changes and step length is based on uncertainty reasoning by using a simple Fuzzy rule. The algorithm's performance is studied with comparisons of two versions of GAs, three versions of DE algorithms and four versions of PSO algorithms on the IEEE 57 and 118-bus power systems. The simulation results show that the proposed approach performed better than the other listed algorithms and can be efficiently used for the ORPD problem. (author)
Optimal pricing of non-utility generated electric power
International Nuclear Information System (INIS)
Siddiqi, S.N.; Baughman, M.L.
1994-01-01
The importance of an optimal pricing policy for pricing non-utility generated power is pointed out in this paper. An optimal pricing policy leads to benefits for all concerned: the utility, industry, and the utility's other customers. In this paper, it is shown that reliability differentiated real-time pricing provides an optimal non-utility generated power pricing policy, from a societal welfare point of view. Firm capacity purchase, and hence an optimal price for purchasing firm capacity, are an integral part of this pricing policy. A case study shows that real-time pricing without firm capacity purchase results in improper investment decisions and higher costs for the system as a whole. Without explicit firm capacity purchase, the utility makes greater investment in capacity addition in order to meet its reliability criteria than is socially optimal. It is concluded that the non-utility generated power pricing policy presented in this paper and implied by reliability differentiated pricing policy results in social welfare-maximizing investment and operation decisions
Adaptive Power Saving Method for Mobile Walking Guidance Device Using Motion Context
Directory of Open Access Journals (Sweden)
Jin-Hee Lee
2015-01-01
Full Text Available It is important to recognize the motion of the user and the surrounding environment with multiple sensors. We developed a guidance system based on mobile device for visually impaired person that helps the user to walk safely to the destination in the previous study. However, a mobile device having multiple sensors spends more power when the sensors are activated simultaneously and continuously. We propose a method for reducing the power consumption of a mobile device by considering the motion context of the user. We analyze and classify the user’s motion accurately by means of a decision tree and HMM (Hidden Markov Model that exploit the data from a triaxial accelerometer sensor and a tilt sensor. We can reduce battery power consumption by controlling the number of active ultrasonic sensors and the frame rate of the camera used to acquire spatial context around the user. This helps us to extend the operating time of the device and reduce the weight of the device’s built-in battery.
New cost saving technologies: microturbines - a new way to generate power
International Nuclear Information System (INIS)
Kline, R.
1999-01-01
The use of microturbines for power distribution was discussed and illustrated by a series of overhead viewgraphs which accompanied this presentation. The paper presented an explanation of how microturbines work and how they can be used for onsite distributed generation. Microturbines were described as being portable and compact gas turbines of less than 100 kW, with high speed single shaft design. One of their main advantages are their capability for remote monitoring and operation. Results of microturbine testing at Suncor's Joffre Plant were presented. Some of the advantages of using Mercury Electric's IPP and TurboGenerator Distributor were also discussed. The operating modes for the unit include: (1) peak shaving for larger load customers, (2) cogeneration for base load applications, (3) emergency/standby/UPS applications, and (4) portable generation for temporary power. The unit can be used in commercial and industrial buildings and is also ideal for remote locations. The environmental benefits associated with the unit is that it can be used for cogeneration power and can utilize waste gas flares which have been associated with harmful emissions to the atmosphere. 7 figs
International Nuclear Information System (INIS)
Derafshian, Mehdi; Amjady, Nima
2015-01-01
This paper presents an evolutionary algorithm-based approach for optimal design of power system stabilizer (PSS) for multi-machine power systems that include doubly fed induction generator wind turbines. The proposed evolutionary algorithm is an improved particle swarm optimization named chaotic particle swarm optimization with passive congregation (CPSO-PC) applied for finding the optimal settings of PSS parameters. Two different eigenvalue-based objectives are combined as the objective function for the optimization problem of tuning PSS parameters. The first objective function comprises the damping factor of lightly damped electro-mechanical modes and the second one includes the damping ratio of these modes. The effectiveness of the proposed method to design PSS for the power systems including DFIG (Doubly Fed Induction Generator) is extensively demonstrated through eigenvalue analysis and time-domain simulations and also by comparing its simulation results with the results of other heuristic optimization approaches. - Highlights: • A new optimization model for design of PSS in power systems including DFIG is proposed. • A detailed and realistic modeling of DFIG is presented. • A new evolutionary algorithm is suggested for solving the optimization problem of designing PSS
Wind Turbine Power Curve Design for Optimal Power Generation in Wind Farms Considering Wake Effect
Directory of Open Access Journals (Sweden)
Jie Tian
2017-03-01
Full Text Available In modern wind farms, maximum power point tracking (MPPT is widely implemented. Using the MPPT method, each individual wind turbine is controlled by its pitch angle and tip speed ratio to generate the maximum active power. In a wind farm, the upstream wind turbine may cause power loss to its downstream wind turbines due to the wake effect. According to the wake model, downstream power loss is also determined by the pitch angle and tip speed ratio of the upstream wind turbine. By optimizing the pitch angle and tip speed ratio of each wind turbine, the total active power of the wind farm can be increased. In this paper, the optimal pitch angle and tip speed ratio are selected for each wind turbine by the exhausted search. Considering the estimation error of the wake model, a solution to implement the optimized pitch angle and tip speed ratio is proposed, which is to generate the optimal control curves for each individual wind turbine off-line. In typical wind farms with regular layout, based on the detailed analysis of the influence of pitch angle and tip speed ratio on the total active power of the wind farm by the exhausted search, the optimization is simplified with the reduced computation complexity. By using the optimized control curves, the annual energy production (AEP is increased by 1.03% compared to using the MPPT method in a case-study of a typical eighty-turbine wind farm.
Stillwater Hybrid Geo-Solar Power Plant Optimization Analyses
Energy Technology Data Exchange (ETDEWEB)
Wendt, Daniel S.; Mines, Gregory L.; Turchi, Craig S.; Zhu, Guangdong; Cohan, Sander; Angelini, Lorenzo; Bizzarri, Fabrizio; Consoli, Daniele; De Marzo, Alessio
2015-09-02
The Stillwater Power Plant is the first hybrid plant in the world able to bring together a medium-enthalpy geothermal unit with solar thermal and solar photovoltaic systems. Solar field and power plant models have been developed to predict the performance of the Stillwater geothermal / solar-thermal hybrid power plant. The models have been validated using operational data from the Stillwater plant. A preliminary effort to optimize performance of the Stillwater hybrid plant using optical characterization of the solar field has been completed. The Stillwater solar field optical characterization involved measurement of mirror reflectance, mirror slope error, and receiver position error. The measurements indicate that the solar field may generate 9% less energy than the design value if an appropriate tracking offset is not employed. A perfect tracking offset algorithm may be able to boost the solar field performance by about 15%. The validated Stillwater hybrid plant models were used to evaluate hybrid plant operating strategies including turbine IGV position optimization, ACC fan speed and turbine IGV position optimization, turbine inlet entropy control using optimization of multiple process variables, and mixed working fluid substitution. The hybrid plant models predict that each of these operating strategies could increase net power generation relative to the baseline Stillwater hybrid plant operations.
Optimization of radiological protection in Spanish nuclear power plants
International Nuclear Information System (INIS)
O'Donnell, P.; Amor, I.; Butragueno, J.L.
1997-01-01
Optimizing the radiological protection of occupationally exposed nuclear power plant workers has become one further item in what is called the safety culture. Spanish facilities are implementing programme with this in mind, grounded on a personal motivation policy with the backing of a suitable organizational structure. (Author)
Using package MESSAGE for optimization studies of nuclear power structures
International Nuclear Information System (INIS)
Andrianov, A.A.; Fedorova, E.V.; Korobejnikov, V.V.; Poplavskaya, E.V.; Rachkova, E.N.
2010-01-01
The results of optimization research of Russia nuclear power strategies, obtained for different assumptions concerning availability of natural uranium resources were presented. The ability of energy planning package MESSAGE (Model for Energy Supply Strategy Alternatives and their General Environmental Impacts) application for elaborating breeding parameters requirements of fast sodium reactors and assessing the required scale of nuclear fuel cycle enterprises development was demonstrated [ru
Optimal trajectory control of a CLCC resonant power converter
Huisman, H.; Visser, de I.; Duarte, J.L.
2015-01-01
A CLCC resonant converter to be used in an isolated power supply is operated using optimal trajectory control (OTC). As a consequence, the converter's inner loop behavior is changed to that of a controlled current source. The controller is implemented in an FPGA. Simulation results and recorded
Efficient relaxations for joint chance constrained AC optimal power flow
Energy Technology Data Exchange (ETDEWEB)
Baker, Kyri; Toomey, Bridget
2017-07-01
Evolving power systems with increasing levels of stochasticity call for a need to solve optimal power flow problems with large quantities of random variables. Weather forecasts, electricity prices, and shifting load patterns introduce higher levels of uncertainty and can yield optimization problems that are difficult to solve in an efficient manner. Solution methods for single chance constraints in optimal power flow problems have been considered in the literature, ensuring single constraints are satisfied with a prescribed probability; however, joint chance constraints, ensuring multiple constraints are simultaneously satisfied, have predominantly been solved via scenario-based approaches or by utilizing Boole's inequality as an upper bound. In this paper, joint chance constraints are used to solve an AC optimal power flow problem while preventing overvoltages in distribution grids under high penetrations of photovoltaic systems. A tighter version of Boole's inequality is derived and used to provide a new upper bound on the joint chance constraint, and simulation results are shown demonstrating the benefit of the proposed upper bound. The new framework allows for a less conservative and more computationally efficient solution to considering joint chance constraints, specifically regarding preventing overvoltages.
Optimization of the scheduled maintenance on the power units of the nuclear power plants with WWER
International Nuclear Information System (INIS)
Skalozubov, V.I.; Kovrizhkin, Yu.L.; Kolykhanov, V.N.; Kochneva, V.Yu.; Urbanskij, V.V.
2008-01-01
The advanced international and domestic experience in the field of the maintenance optimization of the power units of NPPs, as well, as on the base of the planning optimization, the maintenance organization and carrying out, the technical maintenance and repair control system automatization, the testing and monitoring optimization during the service process, the modernization of the technology and technical tools of the maintenance service and control is represented
Optimal power allocation of a sensor node under different rate constraints
Ayala Solares, Jose Roberto; Rezki, Zouheir; Alouini, Mohamed-Slim
2012-01-01
The optimal transmit power of a sensor node while satisfying different rate constraints is derived. First, an optimization problem with an instantaneous transmission rate constraint is addressed. Next, the optimal power is analyzed, but now
Optimal Power Flow for Distribution Systems under Uncertain Forecasts: Preprint
Energy Technology Data Exchange (ETDEWEB)
Dall' Anese, Emiliano; Baker, Kyri; Summers, Tyler
2016-12-01
The paper focuses on distribution systems featuring renewable energy sources and energy storage devices, and develops an optimal power flow (OPF) approach to optimize the system operation in spite of forecasting errors. The proposed method builds on a chance-constrained multi-period AC OPF formulation, where probabilistic constraints are utilized to enforce voltage regulation with a prescribed probability. To enable a computationally affordable solution approach, a convex reformulation of the OPF task is obtained by resorting to i) pertinent linear approximations of the power flow equations, and ii) convex approximations of the chance constraints. Particularly, the approximate chance constraints provide conservative bounds that hold for arbitrary distributions of the forecasting errors. An adaptive optimization strategy is then obtained by embedding the proposed OPF task into a model predictive control framework.
Optimal generator bidding strategies for power and ancillary services
Morinec, Allen G.
As the electric power industry transitions to a deregulated market, power transactions are made upon price rather than cost. Generator companies are interested in maximizing their profits rather than overall system efficiency. A method to equitably compensate generation providers for real power, and ancillary services such as reactive power and spinning reserve, will ensure a competitive market with an adequate number of suppliers. Optimizing the generation product mix during bidding is necessary to maximize a generator company's profits. The objective of this research work is to determine and formulate appropriate optimal bidding strategies for a generation company in both the energy and ancillary services markets. These strategies should incorporate the capability curves of their generators as constraints to define the optimal product mix and price offered in the day-ahead and real time spot markets. In order to achieve such a goal, a two-player model was composed to simulate market auctions for power generation. A dynamic game methodology was developed to identify Nash Equilibria and Mixed-Strategy Nash Equilibria solutions as optimal generation bidding strategies for two-player non-cooperative variable-sum matrix games with incomplete information. These games integrated the generation product mix of real power, reactive power, and spinning reserve with the generators's capability curves as constraints. The research includes simulations of market auctions, where strategies were tested for generators with different unit constraints, costs, types of competitors, strategies, and demand levels. Studies on the capability of large hydrogen cooled synchronous generators were utilized to derive useful equations that define the exact shape of the capability curve from the intersections of the arcs defined by the centers and radial vectors of the rotor, stator, and steady-state stability limits. The available reactive reserve and spinning reserve were calculated given a
Optimal Design of Magnetic ComponentsinPlasma Cutting Power Supply
Jiang, J. F.; Zhu, B. R.; Zhao, W. N.; Yang, X. J.; Tang, H. J.
2017-10-01
Phase-shifted transformer and DC reactor are usually needed in chopper plasma cutting power supply. Because of high power rate, the loss of magnetic components may reach to several kilowatts, which seriously affects the conversion efficiency. Therefore, it is necessary to research and design low loss magnetic components by means of efficient magnetic materials and optimal design methods. The main task in this paper is to compare the core loss of different magnetic material, to analyze the influence of transformer structure, winding arrangement and wire structure on the characteristics of magnetic component. Then another task is to select suitable magnetic material, structure and wire in order to reduce the loss and volume of magnetic components. Based on the above outcome, the optimization design process of transformer and dc reactor are proposed in chopper plasma cutting power supply with a lot of solutions. These solutions are analyzed and compared before the determination of the optimal solution in order to reduce the volume and power loss of the two magnetic components and improve the conversion efficiency of plasma cutting power supply.
Feng, Jun-shu; Jin, Yan-ming; Hao, Wei-hua
2017-01-01
Based on modelling the environmental influence index of power transmission and transformation project and energy-saving and emission-reducing index of source-grid-load of power system, this paper establishes an objective decision model of power grid environmental protection, with constraints of power grid environmental protection objectives being legal and economical, and considering both positive and negative influences of grid on the environmental in all-life grid cycle. This model can be used to guide the programming work of power grid environmental protection. A numerical simulation of Jiangsu province’s power grid environmental protection objective decision model has been operated, and the results shows that the maximum goal of energy-saving and emission-reducing benefits would be reached firstly as investment increasing, and then the minimum goal of environmental influence.
International Nuclear Information System (INIS)
Nakamura, Hidenori
2013-01-01
An online social survey was conducted to reveal household electricity-saving behaviour and its relationship with participation in social group activities, as well as face-to-face and online social interactions, i.e., information sources used and information dissemination through personal networks, in a disaster-affected region of Kanagawa, Japan, during the summer of 2011. The study confirms the positive contribution of respondents’ participation in social group activities to the number of power-saving practices conducted. It also reveals the emergence of voluntary social face-to-face and/or online interactions for power-saving. The study suggests it would be useful to provide effective information to proactive individuals who are closely engaged in power-saving in households and who are proactively disseminating power-saving information practices to others. Such individuals include (1) women who have school-children and who are proactively engaging in the social interactions of their children’s schools, other parents, neighbours, as well as their own parents and relatives; and (2) men and women who are using various kinds of online interaction tools and are also engaged in face-to-face social interactions
The optimization of wireless power transmission: design and realization.
Jia, Zhiwei; Yan, Guozheng; Liu, Hua; Wang, Zhiwu; Jiang, Pingping; Shi, Yu
2012-09-01
A wireless power transmission system is regarded as a practical way of solving power-shortage problems in multifunctional active capsule endoscopes. The uniformity of magnetic flux density, frequency stability and orientation stability are used to evaluate power transmission stability, taking into consideration size and safety constraints. Magnetic field safety and temperature rise are also considered. Test benches are designed to measure the relevent parameters. Finally, a mathematical programming model in which these constraints are considered is proposed to improve transmission efficiency. To verify the feasibility of the proposed method, various systems for a wireless active capsule endoscope are designed and evaluated. The optimal power transmission system has the capability to supply continuously at least 500 mW of power with a transmission efficiency of 4.08%. The example validates the feasibility of the proposed method. Introduction of novel designs enables further improvement of this method. Copyright © 2012 John Wiley & Sons, Ltd.
Apparatus and method for implementing power saving techniques when processing floating point values
Kim, Young Moon; Park, Sang Phill
2017-10-03
An apparatus and method are described for reducing power when reading and writing graphics data. For example, one embodiment of an apparatus comprises: a graphics processor unit (GPU) to process graphics data including floating point data; a set of registers, at least one of the registers of the set partitioned to store the floating point data; and encode/decode logic to reduce a number of binary 1 values being read from the at least one register by causing a specified set of bit positions within the floating point data to be read out as 0s rather than 1s.
Power Consumption in Refrigeration Systems - Modeling for Optimization
DEFF Research Database (Denmark)
Hovgaard, Tobias Gybel; Larsen, Lars F. S.; Skovrup, Morten Juel
2011-01-01
Refrigeration systems consume a substantial amount of energy. Taking for instance supermarket refrigeration systems as an example they can account for up to 50−80% of the total energy consumption in the supermarket. Due to the thermal capacity made up by the refrigerated goods in the system...... there is a possibility for optimizing the power consumption by utilizing load shifting strategies. This paper describes the dynamics and the modeling of a vapor compression refrigeration system needed for sufficiently realistic estimation of the power consumption and its minimization. This leads to a non-convex function...... with possibly multiple extrema. Such a function can not directly be optimized by standard methods and a qualitative analysis of the system’s constraints is presented. The description of power consumption contains nonlinear terms which are approximated by linear functions in the control variables and the error...
Price-based Optimal Control of Electrical Power Systems
Energy Technology Data Exchange (ETDEWEB)
Jokic, A.
2007-09-10
The research presented in this thesis is motivated by the following issue of concern for the operation of future power systems: Future power systems will be characterized by significantly increased uncertainties at all time scales and, consequently, their behavior in time will be difficult to predict. In Chapter 2 we will present a novel explicit, dynamic, distributed feedback control scheme that utilizes nodal-prices for real-time optimal power balance and network congestion control. The term explicit means that the controller is not based on solving an optimization problem on-line. Instead, the nodal prices updates are based on simple, explicitly defined and easily comprehensible rules. We prove that the developed control scheme, which acts on the measurements from the current state of the system, always provide the correct nodal prices. In Chapter 3 we will develop a novel, robust, hybrid MPC control (model predictive controller) scheme for power balance control with hard constraints on line power flows and network frequency deviations. The developed MPC controller acts in parallel with the explicit controller from Chapter 2, and its task is to enforce the constraints during the transient periods following suddenly occurring power imbalances in the system. In Chapter 4 the concept of autonomous power networks will be presented as a concise formulation to deal with economic, technical and reliability issues in power systems with a large penetration of distributed generating units. With autonomous power networks as new market entities, we propose a novel operational structure of ancillary service markets. In Chapter 5 we will consider the problem of controlling a general linear time-invariant dynamical system to an economically optimal operating point, which is defined by a multiparametric constrained convex optimization problem related with the steady-state operation of the system. The parameters in the optimization problem are values of the exogenous inputs to
Virtual power plant mid-term dispatch optimization
International Nuclear Information System (INIS)
Pandžić, Hrvoje; Kuzle, Igor; Capuder, Tomislav
2013-01-01
Highlights: ► Mid-term virtual power plant dispatching. ► Linear modeling. ► Mixed-integer linear programming applied to mid-term dispatch scheduling. ► Operation profit maximization combining bilateral contracts and the day-ahead market. -- Abstract: Wind power plants incur practically zero marginal costs during their operation. However, variable and uncertain nature of wind results in significant problems when trying to satisfy the contracted quantities of delivered electricity. For this reason, wind power plants and other non-dispatchable power sources are combined with dispatchable power sources forming a virtual power plant. This paper considers a weekly self-scheduling of a virtual power plant composed of intermittent renewable sources, storage system and a conventional power plant. On the one hand, the virtual power plant needs to fulfill its long-term bilateral contracts, while, on the other hand, it acts in the market trying to maximize its overall profit. The optimal dispatch problem is formulated as a mixed-integer linear programming model which maximizes the weekly virtual power plant profit subject to the long-term bilateral contracts and technical constraints. The self-scheduling procedure is based on stochastic programming. The uncertainty of the wind power and solar power generation is settled by using pumped hydro storage in order to provide flexible operation, as well as by having a conventional power plant as a backup. The efficiency of the proposed model is rendered through a realistic case study and analysis of the results is provided. Additionally, the impact of different storage capacities and turbine/pump capacities of pumped storage are analyzed.
Optimal Operation of Energy Storage in Power Transmission and Distribution
Akhavan Hejazi, Seyed Hossein
In this thesis, we investigate optimal operation of energy storage units in power transmission and distribution grids. At transmission level, we investigate the problem where an investor-owned independently-operated energy storage system seeks to offer energy and ancillary services in the day-ahead and real-time markets. We specifically consider the case where a significant portion of the power generated in the grid is from renewable energy resources and there exists significant uncertainty in system operation. In this regard, we formulate a stochastic programming framework to choose optimal energy and reserve bids for the storage units that takes into account the fluctuating nature of the market prices due to the randomness in the renewable power generation availability. At distribution level, we develop a comprehensive data set to model various stochastic factors on power distribution networks, with focus on networks that have high penetration of electric vehicle charging load and distributed renewable generation. Furthermore, we develop a data-driven stochastic model for energy storage operation at distribution level, where the distribution of nodal voltage and line power flow are modelled as stochastic functions of the energy storage unit's charge and discharge schedules. In particular, we develop new closed-form stochastic models for such key operational parameters in the system. Our approach is analytical and allows formulating tractable optimization problems. Yet, it does not involve any restricting assumption on the distribution of random parameters, hence, it results in accurate modeling of uncertainties. By considering the specific characteristics of random variables, such as their statistical dependencies and often irregularly-shaped probability distributions, we propose a non-parametric chance-constrained optimization approach to operate and plan energy storage units in power distribution girds. In the proposed stochastic optimization, we consider
Convex relaxation of Optimal Power Flow in Distribution Feeders with embedded solar power
DEFF Research Database (Denmark)
Hermann, Alexander Niels August; Wu, Qiuwei; Huang, Shaojun
2016-01-01
There is an increasing interest in using Distributed Energy Resources (DER) directly coupled to end user distribution feeders. This poses an array of challenges because most of today’s distribution feeders are designed for unidirectional power flow. Therefore when installing DERs such as solar...... panels with uncontrolled inverters, the upper limit of installable capacity is quickly reached in many of today’s distribution feeders. This problem can often be mitigated by optimally controlling the voltage angles of inverters. However, the optimal power flow problem in its standard form is a large...... scale non-convex optimization problem, and thus can’t be solved precisely and also is computationally heavy and intractable for large systems. This paper examines the use of a convex relaxation using Semi-definite programming to optimally control solar power inverters in a distribution grid in order...
Modified Monkey Optimization Algorithm for Solving Optimal Reactive Power Dispatch Problem
Directory of Open Access Journals (Sweden)
Kanagasabai Lenin
2015-04-01
Full Text Available In this paper, a novel approach Modified Monkey optimization (MMO algorithm for solving optimal reactive power dispatch problem has been presented. MMO is a population based stochastic meta-heuristic algorithm and it is inspired by intelligent foraging behaviour of monkeys. This paper improves both local leader and global leader phases. The proposed (MMO algorithm has been tested in standard IEEE 30 bus test system and simulation results show the worthy performance of the proposed algorithm in reducing the real power loss.
Optimal Power Transmission of Offshore Wind Power Using a VSC-HVdc Interconnection
Directory of Open Access Journals (Sweden)
Miguel E. Montilla-DJesus
2017-07-01
Full Text Available High-voltage dc transmission based on voltage-source converter (VSC-HVdc is quickly increasing its power rating, and it can be the most appropriate link for the connection of offshore wind farms (OWFs to the grid in many locations. This paper presents a steady-state operation model to calculate the optimal power transmission of an OWF connected to the grid through a VSC-HVdc link. The wind turbines are based on doubly fed induction generators (DFIGs, and a detailed model of the internal OWF grid is considered in the model. The objective of the optimization problem is to maximize the active power output of the OWF, i.e., the reduction of losses, by considering the optimal reactive power allocation while taking into account the restrictions imposed by the available wind power, the reactive power capability of the DFIG, the DC link model, and the operating conditions. Realistic simulations are performed to evaluate the proposed model and to execute optimal operation analyses. The results show the effectiveness of the proposed method and demonstrate the advantages of using the reactive control performed by DFIG to achieve the optimal operation of the VSC-HVdc.
An Efficient Power Saving Technique Based Location Alarm For Smart Phones
Saranya, G.; Lavanya, S.; Sivasankari, S.
2018-04-01
In today’s world it is not possible for everything to work at the scheduled time. Therefore it is necessary that our daily applications remind us on a particular location instead of a particular time. When the reminder is set, it continuously checks the distance from the destination. If it matches with the maximum distance entered it reminds the user that he/she is about to reach their destination. When the user enters the proximity radius that was set in the application, the user is notified. The application is set to work with availability of GPS as well as mobile network data in the users’ device which runs on android platform. The application also limits the impact of battery life of its device by bringing down the rate of updates and background services when the device battery is low and hence optimizing the battery usage for further important tasks. The location can be either a place or the GPS location of other user. The notification can be enabled on both the users and both the user can be notified based on the proximity radius set by them.
International Nuclear Information System (INIS)
Lopez, P. Reche; Reyes, N. Ruiz; Gonzalez, M. Gomez; Jurado, F.
2008-01-01
With sufficient territory and abundant biomass resources Spain appears to have suitable conditions to develop biomass utilization technologies. As an important decentralized power technology, biomass gasification and power generation has a potential market in making use of biomass wastes. This paper addresses biomass fuelled generation of electricity in the specific aspect of finding the best location and the supply area of the electric generation plant for three alternative technologies (gas motor, gas turbine and fuel cell-microturbine hybrid power cycle), taking into account the variables involved in the problem, such as the local distribution of biomass resources, transportation costs, distance to existing electric lines, etc. For each technology, not only optimal location and supply area of the biomass plant, but also net present value and generated electric power are determined by an own binary variant of Particle Swarm Optimization (PSO). According to the values derived from the optimization algorithm, the most profitable technology can be chosen. Computer simulations show the good performance of the proposed binary PSO algorithm to optimize biomass fuelled systems for distributed power generation. (author)
Magnetic MIMO Signal Processing and Optimization for Wireless Power Transfer
Yang, Gang; Moghadam, Mohammad R. Vedady; Zhang, Rui
2017-06-01
In magnetic resonant coupling (MRC) enabled multiple-input multiple-output (MIMO) wireless power transfer (WPT) systems, multiple transmitters (TXs) each with one single coil are used to enhance the efficiency of simultaneous power transfer to multiple single-coil receivers (RXs) by constructively combining their induced magnetic fields at the RXs, a technique termed "magnetic beamforming". In this paper, we study the optimal magnetic beamforming design in a multi-user MIMO MRC-WPT system. We introduce the multi-user power region that constitutes all the achievable power tuples for all RXs, subject to the given total power constraint over all TXs as well as their individual peak voltage and current constraints. We characterize each boundary point of the power region by maximizing the sum-power deliverable to all RXs subject to their minimum harvested power constraints. For the special case without the TX peak voltage and current constraints, we derive the optimal TX current allocation for the single-RX setup in closed-form as well as that for the multi-RX setup. In general, the problem is a non-convex quadratically constrained quadratic programming (QCQP), which is difficult to solve. For the case of one single RX, we show that the semidefinite relaxation (SDR) of the problem is tight. For the general case with multiple RXs, based on SDR we obtain two approximate solutions by applying time-sharing and randomization, respectively. Moreover, for practical implementation of magnetic beamforming, we propose a novel signal processing method to estimate the magnetic MIMO channel due to the mutual inductances between TXs and RXs. Numerical results show that our proposed magnetic channel estimation and adaptive beamforming schemes are practically effective, and can significantly improve the power transfer efficiency and multi-user performance trade-off in MIMO MRC-WPT systems.
Application of Newton's optimal power flow in voltage/reactive power control
Energy Technology Data Exchange (ETDEWEB)
Bjelogrlic, M.; Babic, B.S. (Electric Power Board of Serbia, Belgrade (YU)); Calovic, M.S. (Dept. of Electrical Engineering, University of Belgrade, Belgrade (YU)); Ristanovic, P. (Institute Nikola Tesla, Belgrade (YU))
1990-11-01
This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.
Control strategies for wind farm power optimization: LES study
Ciri, Umberto; Rotea, Mario; Leonardi, Stefano
2017-11-01
Turbines in wind farms operate in off-design conditions as wake interactions occur for particular wind directions. Advanced wind farm control strategies aim at coordinating and adjusting turbine operations to mitigate power losses in such conditions. Coordination is achieved by controlling on upstream turbines either the wake intensity, through the blade pitch angle or the generator torque, or the wake direction, through yaw misalignment. Downstream turbines can be adapted to work in waked conditions and limit power losses, using the blade pitch angle or the generator torque. As wind conditions in wind farm operations may change significantly, it is difficult to determine and parameterize the variations of the coordinated optimal settings. An alternative is model-free control and optimization of wind farms, which does not require any parameterization and can track the optimal settings as conditions vary. In this work, we employ a model-free optimization algorithm, extremum-seeking control, to find the optimal set-points of generator torque, blade pitch and yaw angle for a three-turbine configuration. Large-Eddy Simulations are used to provide a virtual environment to evaluate the performance of the control strategies under realistic, unsteady incoming wind. This work was supported by the National Science Foundation, Grants No. 1243482 (the WINDINSPIRE project) and IIP 1362033 (I/UCRC WindSTAR). TACC is acknowledged for providing computational time.
International Nuclear Information System (INIS)
Rouelle, P.; Roy, F.
1998-01-01
The Electricite de France's N4 CHOOZ B nuclear power plant, two units of the world's largest PWR model (1450 Mwe each), has earned the Electric Power International's 1997 Powerplant Award. This lead NPP for EDF's N4 series has been improved notably in terms of civil works. The presentation will focus on the Reactor Building's inner containment wall which is one of the main civil structures on a technical and safety point of view. In order to take into account the necessary evolution of the concrete technical specification such as compressive strength low creep and shrinkage, the HSC/HPC has been used on the last N4 Civaux 2 NPP. As a result of the use of this type of professional concrete, the containment withstands an higher internal pressure related to severe accident and ensures higher level of leak-tightness, thus improving the overall safety of the NPP. On that occasion, a new type of prestressing has been tested locally through 55 C 15 S tendons using a new C 1500 FE Jack. These updated civil works techniques shall allow EDF to ensure a Reactor Containment lifespan for more than 50 years. The gains in terms of reliability and cost saving of these improved techniques will be developed hereafter
Optimization of the control of contamination at nuclear power plants
International Nuclear Information System (INIS)
Khan, T.A.; Baum, J.W.
1988-05-01
A methodology is described for the optimization of the actions taken to control contamination. It deals with many aspects of contamination, such as the monetary value assigned to a unit of radiation dose, the treatment of skin and extremity dose, and the inefficiencies introduced from working in a contaminated environemnt. The optimization method is illustrated with two case studies based on cleanup projects at nuclear power plants. Guidelines for the use of protective apparel, and for monitoring radiation and contamination at various levels of contamination are presented. The report concludes that additional research is required to quantify the effect of a contaminated environment on work efficiencies
Optimization of wind farm power production using innovative control strategies
DEFF Research Database (Denmark)
Duc, Thomas
Wind energy has experienced a very significant growth and cost reduction over the past decade, and is now able to compete with conventional power generation sources. New concepts are currently investigated to decrease costs of production of electricity even further. Wind farm coordinated control...... deficit caused by the wake downstream, or yawing the turbine to deflect the wake away from the downwind turbine. Simulation results found in the literature indicate that an increase in overall power production can be obtained. However they underline the high sensitivity of these gains to incoming wind...... aligned wind turbines. The experimental results show that the scenarios implemented during the first measurement campaign did not achieve an increase in overall power production, which confirms the difficulty to realize wind farm power optimization in real operating conditions. In the curtailment field...
Mathematical game type optimization of powerful fast reactors
International Nuclear Information System (INIS)
Pavelesku, M.; Dumitresku, Kh.; Adam, S.
1975-01-01
To obtain maximum speed of putting into operation fast breeders it is recommended on the initial stage of putting into operation these reactors to apply lower power which needs less fission materials. That is why there is an attempt to find a configuration of a high-power reactor providing maximum power for minimum mass of fission material. This problem has a structure of the mathematical game with two partners of non-zero-order total and is solved by means of specific aids of theory of games. Optimal distribution of fission and breeding materials in a multizone reactor first is determined by solution of competitive game and then, on its base, by solution of the cooperation game. The second problem the solution for which is searched is developed from remark on the fact that a reactor with minimum coefficient of flux heterogenity has a configuration different from the reactor with power coefficient heterogenity. Maximum burn-up of fuel needs minimum heterogenity of the flux coefficient and the highest power level needs minimum coefficient of power heterogenity. That is why it is possible to put a problem of finding of the reactor configuration having both coefficients with minimum value. This problem has a structure of a mathematical game with two partners of non-zero-order total and is solved analogously giving optimal distribution of fuel from the new point of view. In the report is shown that both these solutions are independent which is a result of the aim put in the problem of optimization. (author)
Optimization of Passive Low Power Wireless Electromagnetic Energy Harvesters
Nimo, Antwi; Grgić, Dario; Reindl, Leonhard M.
2012-01-01
This work presents the optimization of antenna captured low power radio frequency (RF) to direct current (DC) power converters using Schottky diodes for powering remote wireless sensors. Linearized models using scattering parameters show that an antenna and a matched diode rectifier can be described as a form of coupled resonator with different individual resonator properties. The analytical models show that the maximum voltage gain of the coupled resonators is mainly related to the antenna, diode and load (remote sensor) resistances at matched conditions or resonance. The analytical models were verified with experimental results. Different passive wireless RF power harvesters offering high selectivity, broadband response and high voltage sensitivity are presented. Measured results show that with an optimal resistance of antenna and diode, it is possible to achieve high RF to DC voltage sensitivity of 0.5 V and efficiency of 20% at −30 dBm antenna input power. Additionally, a wireless harvester (rectenna) is built and tested for receiving range performance. PMID:23202014
Optimization of Passive Low Power Wireless Electromagnetic Energy Harvesters
Directory of Open Access Journals (Sweden)
Dario Grgić
2012-10-01
Full Text Available This work presents the optimization of antenna captured low power radio frequency (RF to direct current (DC power converters using Schottky diodes for powering remote wireless sensors. Linearized models using scattering parameters show that an antenna and a matched diode rectifier can be described as a form of coupled resonator with different individual resonator properties. The analytical models show that the maximum voltage gain of the coupled resonators is mainly related to the antenna, diode and load (remote sensor resistances at matched conditions or resonance. The analytical models were verified with experimental results. Different passive wireless RF power harvesters offering high selectivity, broadband response and high voltage sensitivity are presented. Measured results show that with an optimal resistance of antenna and diode, it is possible to achieve high RF to DC voltage sensitivity of 0.5 V and efficiency of 20% at −30 dBm antenna input power. Additionally, a wireless harvester (rectenna is built and tested for receiving range performance.
Yan, Rongge; Guo, Xiaoting; Cao, Shaoqing; Zhang, Changgeng
2018-05-01
Magnetically coupled resonance (MCR) wireless power transfer (WPT) system is a promising technology in electric energy transmission. But, if its system parameters are designed unreasonably, output power and transmission efficiency will be low. Therefore, optimized parameters design of MCR WPT has important research value. In the MCR WPT system with designated coil structure, the main parameters affecting output power and transmission efficiency are the distance between the coils, the resonance frequency and the resistance of the load. Based on the established mathematical model and the differential evolution algorithm, the change of output power and transmission efficiency with parameters can be simulated. From the simulation results, it can be seen that output power and transmission efficiency of the two-coil MCR WPT system and four-coil one with designated coil structure are improved. The simulation results confirm the validity of the optimization method for MCR WPT system with designated coil structure.
Optimizing wind farm cable routing considering power losses
DEFF Research Database (Denmark)
Fischetti, Martina; Pisinger, David
2017-01-01
that must be spent immediately in cable and installation costs, and the future reduced revenues due to power losses. The latter goal has not been addressed in previous work. We present a Mixed-Integer Linear Programming approach to optimize the routing using both exact and math-heuristic methods....... In the power losses computation, wind scenarios are handled eciently as part of the preprocessing, resulting in a MIP model of only slightly larger size. A library of real-life instances is introduced and made publicly available for benchmarking. Computational results on this testbed show the viability of our...
Electric power systems advanced forecasting techniques and optimal generation scheduling
Catalão, João P S
2012-01-01
Overview of Electric Power Generation SystemsCláudio MonteiroUncertainty and Risk in Generation SchedulingRabih A. JabrShort-Term Load ForecastingAlexandre P. Alves da Silva and Vitor H. FerreiraShort-Term Electricity Price ForecastingNima AmjadyShort-Term Wind Power ForecastingGregor Giebel and Michael DenhardPrice-Based Scheduling for GencosGovinda B. Shrestha and Songbo QiaoOptimal Self-Schedule of a Hydro Producer under UncertaintyF. Javier Díaz and Javie
Optimization of heat supply systems employing nuclear power plants
International Nuclear Information System (INIS)
Urbanek, J.
1988-01-01
Decision making on the further development of heat supply systems requires optimization of the parameters. In particular, meeting the demands of peak load ranges is of importance. The heat supply coefficient α and the annual utilization of peak load equipment τ FS have been chosen as the characteristic quantities to describe them. The heat price at the consumer, C V , offers as the optimization criterion. The transport distance, temperature spread of the heating water, and different curves of annual variation of heat consumption on heat supply coefficient and heat price at the consumer. A comparison between heat supply by nuclear power plants and nuclear heating stations verifies the advantage of combined heat and power generation even with longer heat transport distances as compared with local heat supply by nuclear district heating stations based on the criterion of minimum employment of peak load boilers. (author)
Design and optimization of geothermal power generation, heating, and cooling
Kanoglu, Mehmet
Most of the world's geothermal power plants have been built in 1970s and 1980s following 1973 oil crisis. Urgency to generate electricity from alternative energy sources and the fact that geothermal energy was essentially free adversely affected careful designs of plants which would maximize their performance for a given geothermal resource. There are, however, tremendous potentials to improve performance of many existing geothermal power plants by retrofitting, optimizing the operating conditions, re-selecting the most appropriate binary fluid in binary plants, and considering cogeneration such as a district heating and/or cooling system or a system to preheat water entering boilers in industrial facilities. In this dissertation, some representative geothermal resources and existing geothermal power plants in Nevada are investigated to show these potentials. Economic analysis of a typical geothermal resource shows that geothermal heating and cooling may generate up to 3 times as much revenue as power generation alone. A district heating/cooling system is designed for its incorporation into an existing 27 MW air-cooled binary geothermal power plant. The system as designed has the capability to meet the entire heating needs of an industrial park as well as 40% of its cooling needs, generating potential revenues of $14,040,000 per year. A study of the power plant shows that evaporative cooling can increase the power output by up to 29% in summer by decreasing the condenser temperature. The power output of the plant can be increased by 2.8 percent by optimizing the maximum pressure in the cycle. Also, replacing the existing working fluid isobutane by butane, R-114, isopentane, and pentane can increase the power output by up to 2.5 percent. Investigation of some well-known geothermal power generation technologies as alternatives to an existing 12.8 MW single-flash geothermal power plant shows that double-flash, binary, and combined flash/binary designs can increase the
Ser derivation and power optimization of a two-way multirelay cooperative communication system
International Nuclear Information System (INIS)
Rehman, S.U.; Shah, S.I.; Fareed, M.M.
2014-01-01
In this paper, we consider Rayleigh fading based cooperative communication system with AaF (Amplify and Forward) relaying using multiple relays. We take spectrally efficient two-way model of cooperative communication terminals and formulate performance evaluation framework in terms of SER (Symbol Error Rate). We not only consider fading channel for this performance evaluation but also consider the effect of relay terminal location into our model which does not require any CSI (Channel State Information) at transmitting nodes. We have proposed power allocation framework for these nodes and analytically derived SER performance results. We have numerically evaluated this framework for power optimization as well as minimizing required SER. Significant performance improvement as compared with equal power sharing among the cooperating terminals is achieved using our proposed framework. It is shown that virtual cooperative antenna configurations is able to demonstrate up to 3dB gain as compared with co-located antenna configurations. Thus incorporating relay location information for performance evaluation results significant power savings. (author)
SER Derivation and Power Optimization of a Two-Way MultiRelay Cooperative Communication System
Directory of Open Access Journals (Sweden)
Shakeel-Ur-Rehman Rehman
2014-01-01
Full Text Available In this paper, we consider Rayleigh fading based cooperative communication system with AaF (Amplify and Forward relaying using multiple relays. We take spectrally efficient two-way model of cooperative communication terminals and formulate performance evaluation framework in terms of SER (Symbol Error Rate. We not only consider fading channel for this performance evaluation but also consider the effect of relay terminal location into our model which does not require any CSI (Channel State Information at transmitting nodes. We have proposed power allocation framework for these nodes and analytically derived SER performance results. We have numerically evaluated this framework for power optimization as well as minimizing required SER. Significant performance improvement as compared with equal power sharing among the cooperating terminals is achieved using our proposed framework. It is shown that virtual cooperative antenna configurations is able to demonstrate up to 3dB gain as compared with co-located antenna configurations. Thus incorporating relay location information for performance evaluation results significant power savings
Kant Garg, Girish; Garg, Suman; Sangwan, K. S.
2018-04-01
The manufacturing sector consumes huge energy demand and the machine tools used in this sector have very less energy efficiency. Selection of the optimum machining parameters for machine tools is significant for energy saving and for reduction of environmental emission. In this work an empirical model is developed to minimize the power consumption using response surface methodology. The experiments are performed on a lathe machine tool during the turning of AISI 6061 Aluminum with coated tungsten inserts. The relationship between the power consumption and machining parameters is adequately modeled. This model is used for formulation of minimum power consumption criterion as a function of optimal machining parameters using desirability function approach. The influence of machining parameters on the energy consumption has been found using the analysis of variance. The validation of the developed empirical model is proved using the confirmation experiments. The results indicate that the developed model is effective and has potential to be adopted by the industry for minimum power consumption of machine tools.
Enhanced GSA-Based Optimization for Minimization of Power Losses in Power System
Directory of Open Access Journals (Sweden)
Gonggui Chen
2015-01-01
Full Text Available Gravitational Search Algorithm (GSA is a heuristic method based on Newton’s law of gravitational attraction and law of motion. In this paper, to further improve the optimization performance of GSA, the memory characteristic of Particle Swarm Optimization (PSO is employed in GSAPSO for searching a better solution. Besides, to testify the prominent strength of GSAPSO, GSA, PSO, and GSAPSO are applied for the solution of optimal reactive power dispatch (ORPD of power system. Conventionally, ORPD is defined as a problem of minimizing the total active power transmission losses by setting control variables while satisfying numerous constraints. Therefore ORPD is a complicated mixed integer nonlinear optimization problem including many constraints. IEEE14-bus, IEEE30-bus, and IEEE57-bus test power systems are used to implement this study, respectively. The obtained results of simulation experiments using GSAPSO method, especially the power loss reduction rates, are compared to those yielded by the other modern artificial intelligence-based techniques including the conventional GSA and PSO methods. The results presented in this paper reveal the potential and effectiveness of the proposed method for solving ORPD problem of power system.
Robust optimization-based DC optimal power flow for managing wind generation uncertainty
Boonchuay, Chanwit; Tomsovic, Kevin; Li, Fangxing; Ongsakul, Weerakorn
2012-11-01
Integrating wind generation into the wider grid causes a number of challenges to traditional power system operation. Given the relatively large wind forecast errors, congestion management tools based on optimal power flow (OPF) need to be improved. In this paper, a robust optimization (RO)-based DCOPF is proposed to determine the optimal generation dispatch and locational marginal prices (LMPs) for a day-ahead competitive electricity market considering the risk of dispatch cost variation. The basic concept is to use the dispatch to hedge against the possibility of reduced or increased wind generation. The proposed RO-based DCOPF is compared with a stochastic non-linear programming (SNP) approach on a modified PJM 5-bus system. Primary test results show that the proposed DCOPF model can provide lower dispatch cost than the SNP approach.
Optimal Wind Power Uncertainty Intervals for Electricity Market Operation
Energy Technology Data Exchange (ETDEWEB)
Wang, Ying; Zhou, Zhi; Botterud, Audun; Zhang, Kaifeng
2018-01-01
It is important to select an appropriate uncertainty level of the wind power forecast for power system scheduling and electricity market operation. Traditional methods hedge against a predefined level of wind power uncertainty, such as a specific confidence interval or uncertainty set, which leaves the questions of how to best select the appropriate uncertainty levels. To bridge this gap, this paper proposes a model to optimize the forecast uncertainty intervals of wind power for power system scheduling problems, with the aim of achieving the best trade-off between economics and reliability. Then we reformulate and linearize the models into a mixed integer linear programming (MILP) without strong assumptions on the shape of the probability distribution. In order to invest the impacts on cost, reliability, and prices in a electricity market, we apply the proposed model on a twosettlement electricity market based on a six-bus test system and on a power system representing the U.S. state of Illinois. The results show that the proposed method can not only help to balance the economics and reliability of the power system scheduling, but also help to stabilize the energy prices in electricity market operation.
Reference Tracking and Profit Optimization of a Power Plant
DEFF Research Database (Denmark)
Kragelund, Martin Nygaard; Leth, John-Josef; Wisniewski, Rafal
2010-01-01
In this paper we discuss two different methods for implementing reference tracking intro a profit optimization problem of a power plant. It is shown that tracking included as a side constraint results in an significant tracking error only when the reference gradient is large. When tracking...... is included in the cost function, as a quadratic term, the reference is tracked with a small accumulated error. Finally, the two methods are compared both in terms of tracking performance and computational burden....
Optimization criteria for solar and wind power systems
Energy Technology Data Exchange (ETDEWEB)
Salieva, R B
1976-01-01
It is shown that the design of solar and wind power systems requires both the specification of the target function and the optimization of the system with respect to two criteria, namely, the system must be economical (minimum cost to the economy) and it must be reliable (the probability of failure-free operation of the system must be not less than a standard value).
Optimal power and efficiency of quantum Stirling heat engines
Yin, Yong; Chen, Lingen; Wu, Feng
2017-01-01
A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.
Optimization of ultra-low-power CMOS transistors
International Nuclear Information System (INIS)
Stockinger, M.
2000-01-01
Ultra-low-power CMOS integrated circuits have constantly gained importance due to the fast growing portable electronics market. High-performance applications like mobile telephones ask for high-speed computations and low stand-by power consumption to increase the actual operating time. This means that transistors with low leakage currents and high drive currents have to be provided. Common fabrication methods will soon reach their limits if the on-chip feature size of CMOS technology continues to shrink at this very fast rate. New device architectures will help to keep track with the roadmap of the semiconductor industry. Especially doping profiles offer much freedom for performance improvements as they determine the 'inner functioning' of a transistor. In this work automated doping profile optimization is performed on MOS transistors within the TCAD framework SIESTA. The doping between and under the source/drain wells is discretized on an orthogonal optimization grid facilitating almost arbitrary two-dimensional shapes. A linear optimizer issued to find the optimum doping profile by variation of the doping parameters utilizing numerical device simulations with MINIMOS-NT. Gaussian functions are used in further optimization runs to make the doping profiles smooth. Two device generations are considered, one with 0.25 μm, the other with 0.1 μm gate length. The device geometries and source/drain doping profiles are kept fixed during optimization and supply voltages are chosen suitable for ultra-low-power purposes. In a first optimization study the drive current of NMOS transistors is maximized while keeping the leakage current below a limit of 1 pA/μm. This results in peaking channel doping devices (PCD) with narrow doping peaks placed asymmetrically in the channel. Drive current improvements of 45 % and 71 % for the 0.25 μm and 0.1 μm devices, respectively, are achieved compared to uniformly doped devices. The PCD device is studied in detail and explanations for
Optimized Envelope Tracking Power Supply for Tetra2 Base Station RF Power Amplifier
DEFF Research Database (Denmark)
Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.
2008-01-01
An ultra-fast tracking power supply (UFTPS) for envelope tracking in a 50kHz 64-QAM Tetra2 base station power amplification system is demonstrated. A simple method for optimizing the step response of the PID+PD sliding-mode control system is presented and demonstrated, along with a PLL-based scheme...... application. Also demonstrated is the effect of non-zero UFTPS output impedance on envelope tracking performance. At 13W average (156W peak) RF output, a reduction of DC input power consumption from 93W (14% efficiency) to 54W (24% efficiency) is obtained by moving from a fixed RF power amplifier supply...
Thermodynamic performance optimization of a combined power/cooling cycle
International Nuclear Information System (INIS)
Pouraghaie, M.; Atashkari, K.; Besarati, S.M.; Nariman-zadeh, N.
2010-01-01
A combined thermal power and cooling cycle has already been proposed in which thermal energy is used to produce work and to generate a sub-ambient temperature stream that is suitable for cooling applications. The cycle uses ammonia-water mixture as working fluid and is a combination of a Rankine cycle and absorption cycle. The very high ammonia vapor concentration, exiting turbine under certain operating conditions, can provide power output as well as refrigeration. In this paper, the goal is to employ multi-objective algorithms for Pareto approach optimization of thermodynamic performance of the cycle. It has been carried out by varying the selected design variables, namely, turbine inlet pressure (P h ), superheater temperature (T superheat ) and condenser temperature (T condensor ). The important conflicting thermodynamic objective functions that have been considered in this study are turbine work (w T ), cooling capacity (q cool ) and thermal efficiency (η th ) of the cycle. It is shown that some interesting and important relationships among optimal objective functions and decision variables involved in the combined cycle can be discovered consequently. Such important relationships as useful optimal design principles would have not been obtained without the use of a multi-objective optimization approach.
Design optimization of photovoltaic powered water pumping systems
International Nuclear Information System (INIS)
Ghoneim, A.A.
2006-01-01
The use of photovoltaics as the power source for pumping water is one of the most promising areas in photovoltaic applications. With the increased use of water pumping systems, more attention has been paid to their design and optimum utilization in order to achieve the most reliable and economical operation. This paper presents the results of performance optimization of a photovoltaic powered water pumping system in the Kuwait climate. The direct coupled photovoltaic water pumping system studied consists of the PV array, DC motor, centrifugal pump, a storage tank that serves a similar purpose to battery storage and a maximum power point tracker to improve the efficiency of the system. The pumped water is desired to satisfy the domestic needs of 300 persons in a remote area in Kuwait. Assuming a figure of 40 l/person/day for water consumption, a volume of 12 m 3 should be pumped daily from a deep well throughout the year. A computer simulation program is developed to determine the performance of the proposed system in the Kuwait climate. The simulation program consists of a component model for the PV array with maximum power point tracker and component models for both the DC motor and the centrifugal pump. The five parameter model is adapted to simulate the performance of amorphous silicon solar cell modules. The size of the PV array, PV array orientation and the pump-motor-hydraulic system characteristics are varied to achieve the optimum performance for the proposed system. The life cycle cost method is implemented to evaluate the economic feasibility of the optimized photovoltaic powered water pumping system. At the current prices of PV modules, the cost of the proposed photovoltaic powered water pumping system is found to be less expensive than the cost of the conventional fuel system. In addition, the expected reduction in the prices of photovoltaic modules in the near future will make photovoltaic powered water pumping systems more feasible
Cao, Jia; Yan, Zheng; He, Guangyu
2016-06-01
This paper introduces an efficient algorithm, multi-objective human learning optimization method (MOHLO), to solve AC/DC multi-objective optimal power flow problem (MOPF). Firstly, the model of AC/DC MOPF including wind farms is constructed, where includes three objective functions, operating cost, power loss, and pollutant emission. Combining the non-dominated sorting technique and the crowding distance index, the MOHLO method can be derived, which involves individual learning operator, social learning operator, random exploration learning operator and adaptive strategies. Both the proposed MOHLO method and non-dominated sorting genetic algorithm II (NSGAII) are tested on an improved IEEE 30-bus AC/DC hybrid system. Simulation results show that MOHLO method has excellent search efficiency and the powerful ability of searching optimal. Above all, MOHLO method can obtain more complete pareto front than that by NSGAII method. However, how to choose the optimal solution from pareto front depends mainly on the decision makers who stand from the economic point of view or from the energy saving and emission reduction point of view.
Advances in Optimizing Weather Driven Electric Power Systems.
Clack, C.; MacDonald, A. E.; Alexander, A.; Dunbar, A. D.; Xie, Y.; Wilczak, J. M.
2014-12-01
The importance of weather-driven renewable energies for the United States (and global) energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs. The National Energy with Weather System Simulator (NEWS) is a mathematical optimization tool that allows the construction of weather-driven energy sources that will work in harmony with the needs of the system. For example, it will match the electric load, reduce variability, decrease costs, and abate carbon emissions. One important test run included existing US carbon-free power sources, natural gas power when needed, and a High Voltage Direct Current power transmission network. This study shows that the costs and carbon emissions from an optimally designed national system decrease with geographic size. It shows that with achievable estimates of wind and solar generation costs, that the US could decrease its carbon emissions by up to 80% by the early 2030s, without an increase in electric costs. The key requirement would be a 48 state network of HVDC transmission, creating a national market for electricity not possible in the current AC grid. These results were found without the need for storage. Further, we tested the effect of changing natural gas fuel prices on the optimal configuration of the national electric power system. Another test that was carried out was an extension to global regions. The extension study shows that the same properties found in the US study extend to the most populous regions of the planet. The extra test is a simplified version of the US study, and is where much more research can be carried out. We compare our results to other model results.
Energy Technology Data Exchange (ETDEWEB)
2003-07-01
The Energy Smart Guide to Campus Cost Savings covers today's trends in project finance, combined heat& power, clean fuel fleets and emissions trading. The guide is directed at campus facilities and business managers and contains general guidance, contact information and case studies from colleges and universities across the country.
Plant life management optimized utilization of existing nuclear power plants
International Nuclear Information System (INIS)
Watzinger, H.; Erve, M.
1999-01-01
For safe, reliable and economical nuclear power generation it is of central importance to understand, analyze and manage aging-related phenomena and to apply this information in the systematic utilization and as-necessary extension of the service life of components and systems. An operator's overall approach to aging and plant life management which also improves performance characteristics can help to optimize plant operating economy. In view of the deregulation of the power generation industry with its increased competition, nuclear power plants must today also increasingly provide for or maintain a high level of plant availability and low power generating costs. This is a difficult challenge even for the newest, most modern plants, and as plants age they can only remain competitive if a plant operator adopts a strategic approach which takes into account the various aging-related effects on a plant-wide basis. The significance of aging and plant life management for nuclear power plants becomes apparent when looking at their age: By the year 2000 roughly fifty of the world's 434 commercial nuclear power plants will have been in operation for thirty years or more. According to the International Atomic Energy Agency, as many as 110 plants will have reached the thirty-year service mark by the year 2005. In many countries human society does not push the construction of new nuclear power plants and presumably will not change mind within the next ten years. New construction licenses cannot be expected so that for economical and ecological reasons existing plants have to be operated unchallengeably. On the other hand the deregulation of the power production market is asking just now for analysis of plant life time to operate the plants at a high technical and economical level until new nuclear power plants can be licensed and constructed. (author)
Penders, J; Pop, V; Caballero, L; van de Molengraft, J; van Schaijk, R; Vullers, R; Van Hoof, C
2010-01-01
Recent advances in ultra-low-power circuits and energy harvesters are making self-powered body sensor nodes a reality. Power optimization at the system and application level is crucial in achieving ultra-low-power consumption for the entire system. This paper reviews system-level power optimization techniques, and illustrates their impact on the case of autonomous wireless EMG monitoring. The resulting prototype, an Autonomous wireless EMG sensor power by PV-cells, is presented.
Optimization of a Virtual Power Plant to Provide Frequency Support.
Energy Technology Data Exchange (ETDEWEB)
Neely, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lave, Matthew Samuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Delhotal, Jarod James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-12-01
Increasing the penetration of distributed renewable sources, including photovoltaic (PV) sources, poses technical challenges for grid management. The grid has been optimized over decades to rely upon large centralized power plants with well-established feedback controls, but now non-dispatchable, renewable sources are displacing these controllable generators. This one-year study was funded by the Department of Energy (DOE) SunShot program and is intended to better utilize those variable resources by providing electric utilities with the tools to implement frequency regulation and primary frequency reserves using aggregated renewable resources, known as a virtual power plant. The goal is to eventually enable the integration of 100s of Gigawatts into US power systems.
Optimal Time Allocation in Backscatter Assisted Wireless Powered Communication Networks
Lyu, Bin; Yang, Zhen; Gui, Guan; Sari, Hikmet
2017-01-01
This paper proposes a wireless powered communication network (WPCN) assisted by backscatter communication (BackCom). This model consists of a power station, an information receiver and multiple users that can work in either BackCom mode or harvest-then-transmit (HTT) mode. The time block is mainly divided into two parts corresponding to the data backscattering and transmission periods, respectively. The users first backscatter data to the information receiver in time division multiple access (TDMA) during the data backscattering period. When one user works in the BackCom mode, the other users harvest energy from the power station. During the data transmission period, two schemes, i.e., non-orthogonal multiple access (NOMA) and TDMA, are considered. To maximize the system throughput, the optimal time allocation policies are obtained. Simulation results demonstrate the superiority of the proposed model. PMID:28587171
Optimization of power and energy densities in supercapacitors
Energy Technology Data Exchange (ETDEWEB)
Robinson, David B. [Sandia National Laboratories, PO Box 969 MS 9291, Livermore, CA 94551 (United States)
2010-06-01
Supercapacitors use nanoporous electrodes to store large amounts of charge on their high surface areas, and use the ions in electrolytes to carry charge into the pores. Their high power density makes them a potentially useful complement to batteries. However, ion transport through long, narrow channels still limits power and efficiency in these devices. Proper design can mitigate this. Current collector geometry must also be considered once this is done. Here, De Levie's model for porous electrodes is applied to quantitatively predict device performance and to propose optimal device designs for given specifications. Effects unique to nanoscale pores are considered, including that pores may not have enough salt to fully charge. Supercapacitors are of value for electric vehicles, portable electronics, and power conditioning in electrical grids with distributed renewable sources, and that value will increase as new device fabrication methods are developed and proper design accommodates those improvements. Example design outlines for vehicle applications are proposed and compared. (author)
Optimizing wellfield operation in a variable power price regime
DEFF Research Database (Denmark)
Bauer-Gottwein, Peter; Schneider, Raphael; Davidsen, Claus
Wellfield management is a multi-objective optimization problem. One important management objective has been energy efficiency in terms of minimizing the energy footprint (EFP) of delivered water (MWh/m3). However, power systems in most countries are moving in the direction of deregulated power...... use itself. We estimated energy footprint as a function of wellfield pumping rate (EFP-Q relationship) for a wellfield in Denmark using a coupled well and pipe network model. This EFP-Q relationship was subsequently used in a stochastic dynamic programming framework to minimize total cost of operating...... the combined wellfield-storage-demand system over the course of a 2-year planning period based on a time series of observed price on the Danish power market and a deterministic, time-varying hourly water demand. In the SDP setup, hourly pumping rates are the decision variables. Constraints include storage...
Optimal dispatch in dynamic security constrained open power market
International Nuclear Information System (INIS)
Singh, S.N.; David, A.K.
2002-01-01
Power system security is a new concern in the competitive power market operation, because the integration of the system controller and the generation owner has been broken. This paper presents an approach for dynamic security constrained optimal dispatch in restructured power market environment. The transient energy margin using transient energy function (TEF) approach has been used to calculate the stability margin of the system and a hybrid method is applied to calculate the approximate unstable equilibrium point (UEP) that is used to calculate the exact UEP and thus, the energy margin using TEF. The case study results illustrated on two systems shows that the operating mechanisms are compatible with the new business environment. (author)
Nuclear Power Plant Outage Optimization Strategy. 2016 Edition
International Nuclear Information System (INIS)
2016-10-01
This publication is an update of IAEA-TECDOC-1315, Nuclear Power Plant Outage Optimisation Strategy, which was published in 2002, and aims to communicate good outage management practices in a manner that can be used by operators and utilities in Member States. Nuclear power plant outage management is a key factor for safe and economic nuclear power plant performance. This publication discusses plant outage strategy and how this strategy is actually implemented. The main areas that are important for outage optimization that were identified by the utilities and government organizations participating in this report are: 1) organization and management; 2) outage planning and preparation; 3) outage execution; 4) safety outage review; and 5) counter measures to avoid the extension of outages and to facilitate the work in forced outages. Good outage management practices cover many different areas of work and this publication aims to communicate these good practices in a way that they can be used effectively by operators and utilities
Optimization of Combine Heat and Power Plants in the Russian Wholesale Power Market Conditions
Directory of Open Access Journals (Sweden)
I. A. Chuchueva
2015-01-01
Full Text Available The paper concerns the relevant problem to optimize the combine heat and power (CHP plants in the Russian wholesale power market conditions. Since 1975 the CHP plants specialists faced the problem of fuel rate or fuel cost reduction while ensuring the fixed level of heat and power production. The optimality criterion was the fuel rate or fuel cost which has to be minimized. Produced heat and power was paid by known tariff. Since the power market started in 2006 the power payment scheme has essentially changed: produced power is paid by market price. In such condition a new optimality criterion the paper offers is a profit which has to be maximized for the given time horizon. Depending on the optimization horizon the paper suggests four types of the problem urgency, namely: long-term, mid-term, short-term, and operative optimization. It clearly shows that the previous problem of fuel cost minimization is a special case of profit maximization problem. To bring the problem to the mixed-integer linear programming problem a new linear characteristic curves of steam and gas turbine are introduced. Error of linearization is 0.6%. The formal statement of the problem of short-term CHP plants optimization in the market conditions is offered. The problem was solved with IRM software (OpenLinkInternational for seven power plants of JSC “Quadra”: Dyagilevskaya CHP, Kurskaya CHP-1, Lipetskaya CHP-2, Orlovskaya CHP, Kurskaya CHP NWR, Tambovskaya CHP, and Smolenskaya CHP-2.The conducted computational experiment showed that a potential profit is between 1.7% and 4.7% of the fuel cost of different CHP plants and depends on the power plant operation conditions. The potential profit value is 2–3 times higher than analogous estimations, which were obtained solving fuel cost minimization problem. The perspectives of the work are formalization of mid-term and long-term CHP plants optimization problem and development of domestic software for the new problem
Sinaga, R. H. M.; Manik, Y.
2018-03-01
Sibayak Geothermal Power Plant (SGPP) is one of the plants being developed by Pertamina Geothermal Energy (PGE) at the upstream phase. At the downstream phase, State - owned Electricity Company (PLN) through PT. Dizamatra Powerindo is the developer. The gross capacity of the power plant is 13.3 MW, consisting 1 unit of Monoblock (2 MW) developed by PGE and 2 units (2×5.65 MW) operated through Energy Sales Contract by PLN. During the development phase of a geothermal power plant, there is a chance to reduce the utility power in order to increase the overall plant efficiency. Reducing the utility power can be attempted by utilizing the wet bulb temperature fluctuation. In this study, a modeling process is developed by using Engineering Equation Solver (EES) software version 9.430. The possibility of energy saving is indicated by condenser pressure changes as a result of wet bulb temperature fluctuation. The result of this study indicates that the change of condenser pressure is about 50.8% on the constant liquid/gas (L/G) condition of the wet bulb temperature of 15°C to 25°C. Further result indicates that in this power plant, Cooling Tower Fan (CTF) is the facility that has the greatest utility load, followed by Hot Well Pump (HWP). The saving of the greatest utility load is applied trough Variable Frequency Drive (VFD) instrumentation. The result of this modeling has been validated by actual operations data (log sheet). The developed model has also been reviewed trough Specific Steam Consumption (SSC), resulting that constant L/G condition allows the optimum condition on of the wet bulb temperature of 15°C to 25°C.
Multi-objective Reactive Power Optimization Based on Improved Particle Swarm Algorithm
Cui, Xue; Gao, Jian; Feng, Yunbin; Zou, Chenlu; Liu, Huanlei
2018-01-01
In this paper, an optimization model with the minimum active power loss and minimum voltage deviation of node and maximum static voltage stability margin as the optimization objective is proposed for the reactive power optimization problems. By defining the index value of reactive power compensation, the optimal reactive power compensation node was selected. The particle swarm optimization algorithm was improved, and the selection pool of global optimal and the global optimal of probability (p-gbest) were introduced. A set of Pareto optimal solution sets is obtained by this algorithm. And by calculating the fuzzy membership value of the pareto optimal solution sets, individuals with the smallest fuzzy membership value were selected as the final optimization results. The above improved algorithm is used to optimize the reactive power of IEEE14 standard node system. Through the comparison and analysis of the results, it has been proven that the optimization effect of this algorithm was very good.
Particle Swarm Optimization with Various Inertia Weight Variants for Optimal Power Flow Solution
Directory of Open Access Journals (Sweden)
Prabha Umapathy
2010-01-01
Full Text Available This paper proposes an efficient method to solve the optimal power flow problem in power systems using Particle Swarm Optimization (PSO. The objective of the proposed method is to find the steady-state operating point which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow, and voltage. Three different inertia weights, a constant inertia weight (CIW, a time-varying inertia weight (TVIW, and global-local best inertia weight (GLbestIW, are considered with the particle swarm optimization algorithm to analyze the impact of inertia weight on the performance of PSO algorithm. The PSO algorithm is simulated for each of the method individually. It is observed that the PSO algorithm with the proposed inertia weight yields better results, both in terms of optimal solution and faster convergence. The proposed method has been tested on the standard IEEE 30 bus test system to prove its efficacy. The algorithm is computationally faster, in terms of the number of load flows executed, and provides better results than other heuristic techniques.
International Nuclear Information System (INIS)
Berrazouane, S.; Mohammedi, K.
2014-01-01
Highlights: • Optimized fuzzy logic controller (FLC) for operating a standalone hybrid power system based on cuckoo search algorithm. • Comparison between optimized fuzzy logic controller based on cuckoo search and swarm intelligent. • Loss of power supply probability and levelized energy cost are introduced. - Abstract: This paper presents the development of an optimized fuzzy logic controller (FLC) for operating a standalone hybrid power system based on cuckoo search algorithm. The FLC inputs are batteries state of charge (SOC) and net power flow, FLC outputs are the power rate of batteries, photovoltaic and diesel generator. Data for weekly solar irradiation, ambient temperature and load profile are used to tune the proposed controller by using cuckoo search algorithm. The optimized FLC is able to minimize loss of power supply probability (LPSP), excess energy (EE) and levelized energy cost (LEC). Moreover, the results of CS optimization are better than of particle swarm optimization PSO for fuzzy system controller
DEFF Research Database (Denmark)
Chen, Peiyuan; Siano, Pierluigi; Chen, Zhe
2010-01-01
determined by the wind resource and geographic conditions, the location of wind turbines in a power system network may significantly affect the distribution of power flow, power losses, etc. Furthermore, modern WTs with power-electronic interface have the capability of controlling reactive power output...... limit requirements. The method combines the Genetic Algorithm (GA), gradient-based constrained nonlinear optimization algorithm and sequential Monte Carlo simulation (MCS). The GA searches for the optimal locations and capacities of WTs. The gradient-based optimization finds the optimal power factor...... setting of WTs. The sequential MCS takes into account the stochastic behaviour of wind power generation and load. The proposed hybrid optimization method is demonstrated on an 11 kV 69-bus distribution system....
Optimization of Nuclear Reactor power Distribution using Genetic Algorithm
International Nuclear Information System (INIS)
Kim, Hyu Chan
1996-02-01
The main purpose of study is to develop a computer code named as 'MGA-SCOUPE' which can determine an optimal fuel-loading pattern for the nuclear reactor. The developed code, MGA-SCOUPE, automatically lots of searches for the globally optimum solutions based upon the modified Genetic Algorithm(MGA). The optimization goal of the MGA-SCOUPE is (1) the minimization of the deviations in the power peaking factors both at BOC and EOC, and (2) the maximization of the average burnup ration at EOC of the total fuel assemblies. For the reactor core calculation module in the MGA-SCOUPE, the SCOUPE code was partially modified and used. It had been developed originally in MIT and has been used currently in Kyung Hee University. The application of the MGA-SCOUPE to KORI 4-4 Cycle Model show several satisfactory results. Among them, two dominant improvements compared with the SCOUPE code can be summarized as follow: - The MGA-SCOUPE removes the user-dependency problem of the SCOUPE in the optimal loading pattern searches. Therefore, the searching process in the MGA-SCOUPE can be easily automated. - The final fuel loading pattern obtained by the MGA-SCOUPE shows 25.8%, 18.7% reduced standard deviations of the power peaking factors both at BOC and EOC, and 45% increased avg. burnup ratio at EOC compare with those of the SCOUPE
PEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid Vehicle
Directory of Open Access Journals (Sweden)
Tinton Dwi Atmaja
2012-02-01
Full Text Available Page HeaderOpen Journal SystemsJournal HelpUser You are logged in as...aulia My Journals My Profile Log Out Log Out as UserNotifications View (27 new ManageJournal Content SearchBrowse By Issue By Author By Title Other JournalsFont SizeMake font size smaller Make font size default Make font size largerInformation For Readers For Authors For LibrariansKeywords CBPNN Displacement FLC LQG/LTR Mixed PMA Ventilation bottom shear stress direct multiple shooting effective fuzzy logic geoelectrical method hourly irregular wave missile trajectory panoramic image predator-prey systems seawater intrusion segmentation structure development pattern terminal bunt manoeuvre Home About User Home Search Current Archives ##Editorial Board##Home > Vol 23, No 1 (2012 > AtmajaPEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid VehicleTinton Dwi Atmaja, Amin AminAbstractone of the present-day implementation of fuel cell is acting as main power source in Fuel Cell Hybrid Vehicle (FCHV. This paper proposes some strategies to optimize the performance of Polymer Electrolyte Membrane Fuel Cell (PEMFC implanted with auxiliary power source to construct a proper FCHV hybridization. The strategies consist of the most updated optimization method determined from three point of view i.e. Energy Storage System (ESS, hybridization topology and control system analysis. The goal of these strategies is to achieve an optimum hybridization with long lifetime, low cost, high efficiency, and hydrogen consumption rate improvement. The energy storage system strategy considers battery, supercapacitor, and high-speed flywheel as the most promising alternative auxiliary power source. The hybridization topology strategy analyzes the using of multiple storage devices injected with electronic components to bear a higher fuel economy and cost saving. The control system strategy employs nonlinear control system to optimize the ripple factor of the voltage and the current
Chinese National Condition Based Power Dispatching Optimization in Microgrids
Directory of Open Access Journals (Sweden)
Gang Chen
2018-01-01
Full Text Available This paper proposed a study on the power dispatching optimization in the microgrid aiming at Chinese national condition based on PSO algorithm. The whole work is on the basis of the weighted factor variation of the objective function due to different weather conditions. Three cases including the good contamination-diffusing weather condition, the smog weather condition, and the normal condition are considered, respectively. In the case of smog weather, the new energy generation and the battery system will be all out to use as less power as possible from the primary grid so that the pollution produced by coal consumption in the thermal power plants can be upmost reduced. However, in the case of perfect contamination-diffusing weather, the battery is not used to reserve its lifetime, while a large amount of exchanged power from the primary grid is used to obtain a most economic-efficient effect. In normal condition, the power dispatching is performed in a most balanced way considering not only the cost but also the environmental management. The case study in Suzhou Industrial Part confirms the effectiveness of the proposed method in this paper.
Optimal PMU placement using topology transformation method in power systems
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Nadia H.A. Rahman
2016-09-01
Full Text Available Optimal phasor measurement units (PMUs placement involves the process of minimizing the number of PMUs needed while ensuring the entire power system completely observable. A power system is identified observable when the voltages of all buses in the power system are known. This paper proposes selection rules for topology transformation method that involves a merging process of zero-injection bus with one of its neighbors. The result from the merging process is influenced by the selection of bus selected to merge with the zero-injection bus. The proposed method will determine the best candidate bus to merge with zero-injection bus according to the three rules created in order to determine the minimum number of PMUs required for full observability of the power system. In addition, this paper also considered the case of power flow measurements. The problem is formulated as integer linear programming (ILP. The simulation for the proposed method is tested by using MATLAB for different IEEE bus systems. The explanation of the proposed method is demonstrated by using IEEE 14-bus system. The results obtained in this paper proved the effectiveness of the proposed method since the number of PMUs obtained is comparable with other available techniques.
Optimal PMU placement using topology transformation method in power systems.
Rahman, Nadia H A; Zobaa, Ahmed F
2016-09-01
Optimal phasor measurement units (PMUs) placement involves the process of minimizing the number of PMUs needed while ensuring the entire power system completely observable. A power system is identified observable when the voltages of all buses in the power system are known. This paper proposes selection rules for topology transformation method that involves a merging process of zero-injection bus with one of its neighbors. The result from the merging process is influenced by the selection of bus selected to merge with the zero-injection bus. The proposed method will determine the best candidate bus to merge with zero-injection bus according to the three rules created in order to determine the minimum number of PMUs required for full observability of the power system. In addition, this paper also considered the case of power flow measurements. The problem is formulated as integer linear programming (ILP). The simulation for the proposed method is tested by using MATLAB for different IEEE bus systems. The explanation of the proposed method is demonstrated by using IEEE 14-bus system. The results obtained in this paper proved the effectiveness of the proposed method since the number of PMUs obtained is comparable with other available techniques.
Optimal investment strategies in decentralized renewable power generation under uncertainty
International Nuclear Information System (INIS)
Fleten, S.-E.; Maribu, K.M.; Wangensteen, I.
2007-01-01
This paper presents a method for evaluating investments in decentralized renewable power generation under price un certainty. The analysis is applicable for a client with an electricity load and a renewable resource that can be utilized for power generation. The investor has a deferrable opportunity to invest in one local power generating unit, with the objective to maximize the profits from the opportunity. Renewable electricity generation can serve local load when generation and load coincide in time, and surplus power can be exported to the grid. The problem is to find the price intervals and the capacity of the generator at which to invest. Results from a case with wind power generation for an office building suggests it is optimal to wait for higher prices than the net present value break-even price under price uncertainty, and that capacity choice can depend on the current market price and the price volatility. With low price volatility there can be more than one investment price interval for different units with intermediate waiting regions between them. High price volatility increases the value of the investment opportunity, and therefore makes it more attractive to postpone investment until larger units are profitable. (author)
Optimal Placement of Energy Storage and Wind Power under Uncertainty
Directory of Open Access Journals (Sweden)
Pilar Meneses de Quevedo
2016-07-01
Full Text Available Due to the rapid growth in the amount of wind energy connected to distribution grids, they are exposed to higher network constraints, which poses additional challenges to system operation. Based on regulation, the system operator has the right to curtail wind energy in order to avoid any violation of system constraints. Energy storage systems (ESS are considered to be a viable solution to solve this problem. The aim of this paper is to provide the best locations of both ESS and wind power by optimizing distribution system costs taking into account network constraints and the uncertainty associated to the nature of wind, load and price. To do that, we use a mixed integer linear programming (MILP approach consisting of loss reduction, voltage improvement and minimization of generation costs. An alternative current (AC linear optimal power flow (OPF, which employs binary variables to define the location of the generation, is implemented. The proposed stochastic MILP approach has been applied to the IEEE 69-bus distribution network and the results show the performance of the model under different values of installed capacities of ESS and wind power.
International Nuclear Information System (INIS)
Martelli, Emanuele; Capra, Federico; Consonni, Stefano
2015-01-01
This two-part paper proposes an approach based on state-of-the-art numerical optimization methods for simultaneously determining the most profitable design and part-load operation of Combined Heat and Power Organic Rankine Cycles. Compared to the usual design practice, the important advantages of the proposed approach are (i) to consider the part-load performance of the ORC at the design stage, (ii) to optimize not only the cycle variables, but also the main turbine design variables (number of stages, stage loads, rotational speed). In this first part (Part A), the design model and the optimization algorithm are presented and tested on a real-world test case. PGS-COM, a recently proposed hybrid derivative-free algorithm, allows to efficiently tackle the challenging non-smooth black-box problem. - Highlights: • Algorithm for the simultaneous optimization Organic Rakine Cycle and turbine. • Thermodynamic and economic models of boiler, cycle, turbine are developed. • Non-smooth black-box optimization problem is successfully tackled with PGS-COM. • Test cases show that the algorithm returns optimal solutions within 4 min. • Toluene outperforms MDM (a siloxane) in terms of efficiency and costs.
Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin
2015-07-03
We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices.
Optimization of powered Stirling heat engine with finite speed thermodynamics
International Nuclear Information System (INIS)
Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar; Hosseinzade, Hadi; Feidt, Michel
2016-01-01
Highlights: • Based on finite speed method and direct method, the optimal performance is investigated. • The effects of major parameters on the optimal performance are investigated. • The accuracy of the results was compared with previous works. - Abstract: Popular thermodynamic analyses including finite time thermodynamic analysis was lately developed based upon external irreversibilities while internal irreversibilities such as friction, pressure drop and entropy generation were not considered. The aforementioned disadvantage reduces the reliability of the finite time thermodynamic analysis in the design of an accurate Stirling engine model. Consequently, the finite time thermodynamic analysis could not sufficiently satisfy researchers for implementing in design and optimization issues. In this study, finite speed thermodynamic analysis was employed instead of finite time thermodynamic analysis for studying Stirling heat engine. The finite speed thermodynamic analysis approach is based on the first law of thermodynamics for a closed system with finite speed and the direct method. The effects of heat source temperature, regenerating effectiveness, volumetric ratio, piston stroke as well as rotational speed are included in the analysis. Moreover, maximum output power in optimal rotational speed was calculated while pressure losses in the Stirling engine were systematically considered. The result reveals the accuracy and the reliability of the finite speed thermodynamic method in thermodynamic analysis of Stirling heat engine. The outcomes can help researchers in the design of an appropriate and efficient Stirling engine.
Baygin, Mehmet; Karakose, Mehmet
2013-01-01
Nowadays, the increasing use of group elevator control systems owing to increasing building heights makes the development of high-performance algorithms necessary in terms of time and energy saving. Although there are many studies in the literature about this topic, they are still not effective enough because they are not able to evaluate all features of system. In this paper, a new approach of immune system-based optimal estimate is studied for dynamic control of group elevator systems. The method is mainly based on estimation of optimal way by optimizing all calls with genetic, immune system and DNA computing algorithms, and it is evaluated with a fuzzy system. The system has a dynamic feature in terms of the situation of calls and the option of the most appropriate algorithm, and it also adaptively works in terms of parameters such as the number of floors and cabins. This new approach which provides both time and energy saving was carried out in real time. The experimental results comparatively demonstrate the effects of method. With dynamic and adaptive control approach in this study carried out, a significant progress on group elevator control systems has been achieved in terms of time and energy efficiency according to traditional methods.
Directory of Open Access Journals (Sweden)
Mehmet Baygin
2013-01-01
Full Text Available Nowadays, the increasing use of group elevator control systems owing to increasing building heights makes the development of high-performance algorithms necessary in terms of time and energy saving. Although there are many studies in the literature about this topic, they are still not effective enough because they are not able to evaluate all features of system. In this paper, a new approach of immune system-based optimal estimate is studied for dynamic control of group elevator systems. The method is mainly based on estimation of optimal way by optimizing all calls with genetic, immune system and DNA computing algorithms, and it is evaluated with a fuzzy system. The system has a dynamic feature in terms of the situation of calls and the option of the most appropriate algorithm, and it also adaptively works in terms of parameters such as the number of floors and cabins. This new approach which provides both time and energy saving was carried out in real time. The experimental results comparatively demonstrate the effects of method. With dynamic and adaptive control approach in this study carried out, a significant progress on group elevator control systems has been achieved in terms of time and energy efficiency according to traditional methods.
SiGe HBTs Optimization for Wireless Power Amplifier Applications
Directory of Open Access Journals (Sweden)
Pierre-Marie Mans
2010-01-01
Full Text Available This paper deals with SiGe HBTs optimization for power amplifier applications dedicated to wireless communications. In this work, we investigate the fT-BVCEO tradeoff by various collector optimization schemes such as epilayer thickness and dopant concentration, and SIC and CAP characteristics. Furthermore, a new trapezoidal base Germanium (Ge profile is proposed. Thanks to this profile, precise control of Ge content at the metallurgical emitter-base junction is obtained. Gain stability is obtained for a wide range of temperatures through tuning the emitter-base junction Ge percent. Finally, a comprehensive investigation of Ge introduction into the collector (backside Ge profile is conducted in order to improve the fT values at high injection levels.
A Hybrid Genetic Algorithm Approach for Optimal Power Flow
Directory of Open Access Journals (Sweden)
Sydulu Maheswarapu
2011-08-01
Full Text Available This paper puts forward a reformed hybrid genetic algorithm (GA based approach to the optimal power flow. In the approach followed here, continuous variables are designed using real-coded GA and discrete variables are processed as binary strings. The outcomes are compared with many other methods like simple genetic algorithm (GA, adaptive genetic algorithm (AGA, differential evolution (DE, particle swarm optimization (PSO and music based harmony search (MBHS on a IEEE30 bus test bed, with a total load of 283.4 MW. Its found that the proposed algorithm is found to offer lowest fuel cost. The proposed method is found to be computationally faster, robust, superior and promising form its convergence characteristics.
Running from features: Optimized evaluation of inflationary power spectra
Motohashi, Hayato; Hu, Wayne
2015-08-01
In models like axion monodromy, temporal features during inflation which are not associated with its ending can produce scalar, and to a lesser extent, tensor power spectra where deviations from scale-free power law spectra can be as large as the deviations from scale invariance itself. Here the standard slow-roll approach breaks down since its parameters evolve on an e -folding scale Δ N much smaller than the e -folds to the end of inflation. Using the generalized slow-roll approach, we show that the expansion of observables in a hierarchy of potential or Hubble evolution parameters comes from a Taylor expansion of the features around an evaluation point that can be optimized. Optimization of the leading-order expression provides a sufficiently accurate approximation for current data as long as the power spectrum can be described over the well-observed few e -folds by the local tilt and running. Standard second-order approaches, often used in the literature, ironically are worse than leading-order approaches due to inconsistent evaluation of observables. We develop a new optimized next-order approach which predicts observables to 10-3 even for Δ N ˜1 where all parameters in the infinite hierarchy are of comparable magnitude. For models with Δ N ≪1 , the generalized slow-roll approach provides integral expressions that are accurate to second order in the deviation from scale invariance. Their evaluation in the monodromy model provides highly accurate explicit relations between the running oscillation amplitude, frequency, and phase in the curvature spectrum and parameters of the potential.
Wolf Search Algorithm for Solving Optimal Reactive Power Dispatch Problem
Directory of Open Access Journals (Sweden)
Kanagasabai Lenin
2015-03-01
Full Text Available This paper presents a new bio-inspired heuristic optimization algorithm called the Wolf Search Algorithm (WSA for solving the multi-objective reactive power dispatch problem. Wolf Search algorithm is a new bio – inspired heuristic algorithm which based on wolf preying behaviour. The way wolves search for food and survive by avoiding their enemies has been imitated to formulate the algorithm for solving the reactive power dispatches. And the speciality of wolf is possessing both individual local searching ability and autonomous flocking movement and this special property has been utilized to formulate the search algorithm .The proposed (WSA algorithm has been tested on standard IEEE 30 bus test system and simulation results shows clearly about the good performance of the proposed algorithm .
Framework for optimal power flow incorporating dynamic system security
International Nuclear Information System (INIS)
El-Kady, M.A.; Owayedh, M.S.
2006-01-01
This paper introduces a novel framework and methodologies which are capable of tackling the complex issue of power system economy versus security in a practical and effective manner. At heart of achieving such a challenging and far-reaching objective is the incorporation of the Dyanamic Security Assessment (DSA) into production optimization techniques using the Transient Energy Function (TEF) method. In addition, and in parallel with the already well established concept of the system security, two new concepts pertaining to power system performance will be introduced in this paper, namely the concept of system dynamic susceptibility, which measures the level of systems weakness to a particular contingency and the concept of system consequent restorability, which measures the extent of contingency severity in terms of the required subsequent system restoration work should a particular contingency occur. (author)
Optimization of nonthermal fusion power consistent with energy channeling
International Nuclear Information System (INIS)
Snyder, P.B.; Herrmann, M.C.; Fisch, N.J.
1995-02-01
If the energy of charged fusion products can be diverted directly to fuel ions, non-Maxwellian fuel ion distributions and temperature differences between species will result. To determine the importance of these nonthermal effects, the fusion power density is optimized at constant-β for nonthermal distributions that are self-consistently maintained by channeling of energy from charged fusion products. For D-T and D- 3 He reactors, with 75% of charged fusion product power diverted to fuel ions, temperature differences between electrons and ions increase the reactivity by 40-70%, while non- Maxwellian fuel ion distributions and temperature differences between ionic species increase the reactivity by an additional 3-15%
Parametric optimization of thermoelectric elements footprint for maximum power generation
DEFF Research Database (Denmark)
Rezania, A.; Rosendahl, Lasse; Yin, Hao
2014-01-01
The development studies in thermoelectric generator (TEG) systems are mostly disconnected to parametric optimization of the module components. In this study, optimum footprint ratio of n- and p-type thermoelectric (TE) elements is explored to achieve maximum power generation, maximum cost......-performance, and variation of efficiency in the uni-couple over a wide range of the heat transfer coefficient on the cold junction. The three-dimensional (3D) governing equations of the thermoelectricity and the heat transfer are solved using the finite element method (FEM) for temperature dependent properties of TE...... materials. The results, which are in good agreement with the previous computational studies, show that the maximum power generation and the maximum cost-performance in the module occur at An/Ap
Optimization design of power efficiency of exponential impedance transformer
International Nuclear Information System (INIS)
Wang Meng; Zou Wenkang; Chen Lin; Guan Yongchao; Fu Jiabin; Xie Weiping
2011-01-01
The paper investigates the optimization design of power efficiency of exponential impedance transformer with analytic method and numerical method. In numerical calculation, a sine wave Jantage with hypothesis of rising edge equivalence is regarded as the forward-going Jantage at input of transformer, and its dominant angular frequency is determined by typical rise-time of actual Jantage waveforms. At the same time, dissipative loss in water dielectric is neglected. The numerical results of three typical modes of impedance transformation, viz. linear mode, saturation mode and steep mode,are compared. Pivotal factors which affect the power efficiency of exponential impedance transformer are discussed, and a certain extent quantitative range of intermediate variables and accordance coefficients are obtained. Finally, the paper discusses some important issues in actual design, such as insulation safety factor in structure design, effects of coupling capacitance on impedance calculation, and dissipative loss in water dielectric. (authors)
Optimizing wind farm cable routing considering power losses
DEFF Research Database (Denmark)
Fischetti, Martina; Pisinger, David
2017-01-01
Wind energy is the fastest growing source of renewable energy, but as wind farms are getting larger and more remotely located, installation and infrastructure costs are rising. It is estimated that the expenses for electrical infrastructure account for 15-30% of the overall initial costs, hence...... that must be spent immediately in cable and installation costs, and the future reduced revenues due to power losses. The latter goal has not been addressed in previous work. We present a Mixed-Integer Linear Programming approach to optimize the routing using both exact and math-heuristic methods....... In the power losses computation, wind scenarios are handled eciently as part of the preprocessing, resulting in a MIP model of only slightly larger size. A library of real-life instances is introduced and made publicly available for benchmarking. Computational results on this testbed show the viability of our...
Optimizing wind farm cable routing considering power losses
DEFF Research Database (Denmark)
Fischetti, Martina; Pisinger, David
Wind energy is the fastest growing source of renewable energy, but as wind farms are getting larger and more remotely located, installation and infrastructure costs are rising. It is estimated that the expenses for electrical infrastructure account for 15-30% of the overall initial costs, hence...... that must be spent immediately in cable and installation costs, and the future reduced revenues due to power losses. The latter goal has not been addressed in previous work. We present a Mixed-Integer Linear Programming approach to optimize the routing using both exact and math-heuristic methods....... In the power losses computation, wind scenarios are handled eciently as part of the preprocessing, resulting in a MIP model of only slightly larger size. A library of real-life instances is introduced and made publicly available for benchmarking. Computational results on this testbed show the viability of our...
Optimal design of condenser volume in nuclear power plant
International Nuclear Information System (INIS)
Zheng Jing; Yan Changqi; Wang Jianjun
2011-01-01
The condenser is an important component in the nuclear power plant,whose dimension will influence the economy and the arrangement of the nuclear power plant.In this paper, the calculation model was established according to the design experience. The corresponding codes were also developed. The sensitivity of design parameters which influence the condenser Janume was analyzed. The present optimal design of the condenser, aiming at the volume minimization, was carried out with the self-developed complex-genetic algorithm. The results show that the reference condenser design is far from the best scheme. In addition, the results also verify the feasibility of the complex-genetic algorithm. Furthermore, the results of this paper can provide reference for the design of the condenser. (authors)
Optimal utilization of electric power in the Nordic countries
International Nuclear Information System (INIS)
Magnusson, G.; Gjelsvik, E.
1992-01-01
It is attempted to address the questions of which advantages the equilibrium solution would have for the energy market under free trade conditions, how Nordic electric power can be used optimally and what the trading pattern looks like, which kind of competition the transmission of electricity via cables to Iceland and other Nordic countries will meet in the United Kingdom (UK) and the Continent, how high the option values are of trading with electric power via cables from, for example, Iceland to the UK and how great the profit could be from a more effective use of electricity for aluminium production in Norway and Iceland. Data are given on consumer prices for 1990 in Scandinavia, Germany and the UK, and a few graphs and a map illustrate the text. (AB)
Optimizing Wellfield Operation in a Variable Power Price Regime
DEFF Research Database (Denmark)
Bauer-Gottwein, Peter; Schneider, Raphael; Davidsen, Claus
2016-01-01
Wellfield management is a multiobjective optimization problem. One important objective has been energy efficiency in terms of minimizing the energy footprint (EFP) of delivered water (MWh/m3). However, power systems in most countries are moving in the direction of deregulated markets and price...... itself. We estimated EFP of pumped water as a function of wellfield pumping rate (EFP-Q relationship) for a wellfield in Denmark using a coupled well and pipe network model. This EFP-Q relationship was subsequently used in a Stochastic Dynamic Programming (SDP) framework to minimize total cost...... of operating the combined wellfield-storage-demand system over the course of a 2-year planning period based on a time series of observed price on the Danish power market and a deterministic, time-varying hourly water demand. In the SDP setup, hourly pumping rates are the decision variables. Constraints include...
International Nuclear Information System (INIS)
McKim, G.; Yeager, M.; Weirich, C.
2006-01-01
Nuclear power plant control systems of 1970's vintage have reached the end of their life: reliability is poor and spare parts are hard to come by. At First Energy Perry station, two costly feedwater system trips caused by an ailing analog control system led to the decision to replace it with a modern Foxboro I/A-series Distributed Control System. The simulator was also upgraded using the Virtual-Stim simulation of I/A, called FSIM. Virtual-Stim simulation allows the configuration and graphics from the plant to be downloaded onto the simulator as-is, using the same tools and operator interface as the plant, without imprecise translations, conversions, or other emulation. Advances in simulation technology and market forces have led to an open architecture design, allowing FSIM to be 'bridged' to Perry's existing Opensim simulator process model. This appears to be an industry-wide trend as more control system vendors offer Virtual Stimulation solutions for connection to third-party simulation products. Taking a cue from First Energy's Sammis Station FSIM simulator projects, the Perry simulator was used for dedicated control verification and tuning. Preventing forced outages caused by control configuration errors can result in enormous savings, and the simulator is now required to precede any plant modifications rather than just a training tool that lags the plant. This testing revealed several surprising results for a relatively straightforward control strategy, showing that simulator-based testing will be even more crucial in the future as the remain-der of the balance of plant is migrated to digital control. (author)
Jin, Meihua; Jung, Ji-Young; Lee, Jung-Ryun
2016-10-12
With the arrival of the era of Internet of Things (IoT), Wi-Fi Direct is becoming an emerging wireless technology that allows one to communicate through a direct connection between the mobile devices anytime, anywhere. In Wi-Fi Direct-based IoT networks, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi Direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi Direct standard defines two power-saving methods: Opportunistic and Notice of Absence (NoA) power-saving methods. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi Direct power-saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the lengths of awake intervals in a beacon interval dynamically. In addition, considering the inter-dependency among video frames, the proposed algorithm ensures that a video frame having high priority is transmitted with higher probability than other frames having low priority. Simulation results show that the proposed method outperforms the traditional NoA method in terms of average delay and energy efficiency.
International Nuclear Information System (INIS)
Mohagheghi Fard, Soheil; Khajepour, Amir
2016-01-01
Highlights: • A new anti-idling system for refrigerator trucks is proposed. • This system enables regenerative braking. • An innovative two-level controller is proposed for the power management system. • A fast dynamic programming technique to find real-time SOC trajectory is proposed. • In addition to idling elimination, this system reduces fuel consumption. - Abstract: Engine idling of refrigerator trucks during loading and unloading contributes to greenhouse gas emissions due to their increased fuel consumption. This paper proposes a new anti-idling system that uses two sources of power, battery and engine-driven generator, to run the compressor of the refrigeration system. Therefore, idling can be eliminated because the engine is turned OFF and the battery supplies auxiliary power when the vehicle is stopped for loading or unloading. This system also takes advantage of regenerative braking for increased fuel savings. The power management of this system needs to satisfy two requirements: it must minimize fuel consumption in the whole cycle and must ensure that the battery has enough energy for powering the refrigeration system when the engine is OFF. To meet these objectives, a two-level controller is proposed. In the higher level of this controller, a fast dynamic programming technique that utilizes extracted statistical features of drive and duty cycles of a refrigerator truck is used to find suboptimal values of the initial and final SOC of any two consecutive loading/unloading stops. The lower level of the controller employs an adaptive equivalent fuel consumption minimization (A-ECMS) to determine the split ratio of auxiliary power between the generator and battery for each segment with initial and final SOC obtained by the high-level controller. The simulation results confirm that this new system can eliminate idling of refrigerator trucks and reduce their fuel consumption noticeably such that the cost of replacing components is recouped in a
SimWIND: A geospatial infrastructure model for optimizing wind power generation and transmission
International Nuclear Information System (INIS)
Phillips, Benjamin R.; Middleton, Richard S.
2012-01-01
Wind is a clean, enduring energy resource with the capacity to satisfy 20% or more of U.S. electricity demand. Presently, wind potential is limited by a paucity of electrical transmission lines and/or capacity between promising wind resources and primary load centers. We present the model SimWIND to address this shortfall. SimWIND is an integrated optimization model for the geospatial arrangement and cost minimization of wind-power generation–transmission–delivery infrastructure. Given a set of possible wind-farm sites, the model simultaneously determines (1) where and how much power to generate and (2) where to build new transmission infrastructure and with what capacity in order to minimize the cost for delivering a targeted amount of power to load. Costs and routing of transmission lines consider geographic and social constraints as well as electricity losses. We apply our model to the Electric Reliability Council of Texas (ERCOT) Interconnection, considering scenarios that deliver up to 20 GW of new wind power. We show that SimWIND could potentially reduce ERCOT's projected ∼$5B transmission network upgrade line length and associated costs by 50%. These results suggest that SimWIND's coupled generation–transmission–delivery modeling approach could play a critical role in enhancing planning efforts and reducing costs for wind energy integration. - Highlights: ► Wind power is limited by transmission capacity between resources and demands. ► SimWIND is a coupled generation-transmission-delivery model for wind infrastructure. ► The model minimizes costs considering realistic transmission routing and networking. ► We show that SimWIND could save 50% of $5B costs for expanding the Texas grid. ► Results suggest SimWIND may play a critical role in enhancings wind planning efforts.
Optimal wind power deployment in Europe. A portfolio approach
International Nuclear Information System (INIS)
Roques, Fabien; Hiroux, Celine; Saguan, Marcelo
2010-01-01
Geographic diversification of wind farms can smooth out the fluctuations in wind power generation and reduce the associated system balancing and reliability costs. The paper uses historical wind production data from five European countries (Austria, Denmark, France, Germany, and Spain) and applies the Mean-Variance Portfolio theory to identify cross-country portfolios that minimise the total variance of wind production for a given level of production. Theoretical unconstrained portfolios show that countries (Spain and Denmark) with the best wind resource or whose size contributes to smoothing out the country output variability dominate optimal portfolios. The methodology is then elaborated to derive optimal constrained portfolios taking into account national wind resource potential and transmission constraints and compare them with the projected portfolios for 2020. Such constraints limit the theoretical potential efficiency gains from geographical diversification, but there is still considerable room to improve performance from actual or projected portfolios. These results highlight the need for more cross-border interconnection capacity, for greater coordination of European renewable support policies, and for renewable support mechanisms and electricity market designs providing locational incentives. Under these conditions, a mechanism for renewables credits trading could help aligning wind power portfolios with the theoretically efficient geographic dispersion. (author)
Performance analysis and optimization of power plants with gas turbines
Besharati-Givi, Maryam
The gas turbine is one of the most important applications for power generation. The purpose of this research is performance analysis and optimization of power plants by using different design systems at different operation conditions. In this research, accurate efficiency calculation and finding optimum values of efficiency for design of chiller inlet cooling and blade cooled gas turbine are investigated. This research shows how it is possible to find the optimum design for different operation conditions, like ambient temperature, relative humidity, turbine inlet temperature, and compressor pressure ratio. The simulated designs include the chiller, with varied COP and fogging cooling for a compressor. In addition, the overall thermal efficiency is improved by adding some design systems like reheat and regenerative heating. The other goal of this research focuses on the blade-cooled gas turbine for higher turbine inlet temperature, and consequently, higher efficiency. New film cooling equations, along with changing film cooling effectiveness for optimum cooling air requirement at the first-stage blades, and an internal and trailing edge cooling for the second stage, are innovated for optimal efficiency calculation. This research sets the groundwork for using the optimum value of efficiency calculation, while using inlet cooling and blade cooling designs. In the final step, the designed systems in the gas cycles are combined with a steam cycle for performance improvement.
Optimal power flow for distribution networks with distributed generation
Directory of Open Access Journals (Sweden)
Radosavljević Jordan
2015-01-01
Full Text Available This paper presents a genetic algorithm (GA based approach for the solution of the optimal power flow (OPF in distribution networks with distributed generation (DG units, including fuel cells, micro turbines, diesel generators, photovoltaic systems and wind turbines. The OPF is formulated as a nonlinear multi-objective optimization problem with equality and inequality constraints. Due to the stochastic nature of energy produced from renewable sources, i.e. wind turbines and photovoltaic systems, as well as load uncertainties, a probabilisticalgorithm is introduced in the OPF analysis. The Weibull and normal distributions are employed to model the input random variables, namely the wind speed, solar irradiance and load power. The 2m+1 point estimate method and the Gram Charlier expansion theory are used to obtain the statistical moments and the probability density functions (PDFs of the OPF results. The proposed approach is examined and tested on a modified IEEE 34 node test feeder with integrated five different DG units. The obtained results prove the efficiency of the proposed approach to solve both deterministic and probabilistic OPF problems for different forms of the multi-objective function. As such, it can serve as a useful decision-making supporting tool for distribution network operators. [Projekat Ministarstva nauke Republike Srbije, br. TR33046
Optimal Subinterval Selection Approach for Power System Transient Stability Simulation
Directory of Open Access Journals (Sweden)
Soobae Kim
2015-10-01
Full Text Available Power system transient stability analysis requires an appropriate integration time step to avoid numerical instability as well as to reduce computational demands. For fast system dynamics, which vary more rapidly than what the time step covers, a fraction of the time step, called a subinterval, is used. However, the optimal value of this subinterval is not easily determined because the analysis of the system dynamics might be required. This selection is usually made from engineering experiences, and perhaps trial and error. This paper proposes an optimal subinterval selection approach for power system transient stability analysis, which is based on modal analysis using a single machine infinite bus (SMIB system. Fast system dynamics are identified with the modal analysis and the SMIB system is used focusing on fast local modes. An appropriate subinterval time step from the proposed approach can reduce computational burden and achieve accurate simulation responses as well. The performance of the proposed method is demonstrated with the GSO 37-bus system.
Wind Plant Power Optimization and Control under Uncertainty
Jha, Pankaj; Ulker, Demet; Hutchings, Kyle; Oxley, Gregory
2017-11-01
The development of optimized cooperative wind plant control involves the coordinated operation of individual turbines co-located within a wind plant to improve the overall power production. This is typically achieved by manipulating the trajectory and intensity of wake interactions between nearby turbines, thereby reducing wake losses. However, there are various types of uncertainties involved, such as turbulent inflow and microscale and turbine model input parameters. In a recent NREL-Envision collaboration, a controller that performs wake steering was designed and implemented for the Longyuan Rudong offshore wind plant in Jiangsu, China. The Rudong site contains 25 Envision EN136-4 MW turbines, of which a subset was selected for the field test campaign consisting of the front two rows for the northeasterly wind direction. In the first row, a turbine was selected as the reference turbine, providing comparison power data, while another was selected as the controlled turbine. This controlled turbine wakes three different turbines in the second row depending on the wind direction. A yaw misalignment strategy was designed using Envision's GWCFD, a multi-fidelity plant-scale CFD tool based on SOWFA with a generalized actuator disc (GAD) turbine model, which, in turn, was used to tune NREL's FLORIS model used for wake steering and yaw control optimization. The presentation will account for some associated uncertainties, such as those in atmospheric turbulence and wake profile.
Energy Technology Data Exchange (ETDEWEB)
Tsuchiyama, M. [Kansai Electric Power Co. Inc., Osaka (Japan)
1999-06-10
This paper presents power load leveling and energy saving measures for heat source, air conditioning and lighting of the new Kobe branch building. The low-temperature hot-air system adopts an ice storage system, and reduces blowing power by 12 degreesC blowing in place of normal 16 degreesC blowing, and an initial cost by duct size reduction. The continuous air conditioning system levels an initial peak load of air conditioning as compared with normal air conditioning only for working hours for buildings with large heat capacity. In addition, as power load leveling measures for the whole building, the complete heat storage system using an underground internal melting type ice storage tank is adopted. Energy saving for lighting is achieved with a dimming lighting controlling its lighting output by inverter. The following effects are expected by these new technologies: Load leveling effect of 30%, energy saving effect of 20.2% and CO{sub 2} reduction effect of 24.1%. (NEDO)
Optimal Procedure for siting of Nuclear Power Plant
International Nuclear Information System (INIS)
Aziuddin, Khairiah Binti; Park, Seo Yeon; Roh, Myung Sub
2013-01-01
This study discusses on a simulation approach for sensitivity analysis of the weights of multi-criteria decision models. The simulation procedures can also be used to aid the actual decision process, particularly when the task is to select a subset of superior alternatives. This study is to identify the criteria or parameters which are sensitive to the weighting factor that can affect the results in the decision making process to determine the optimal site for nuclear power plant (NPP) site. To perform this study, we adhere to IAEA NS-R-3 and DS 433. The siting process for nuclear installation consists of site survey and site selection stages. The siting process generally consists of an investigation of a large region to select one or more candidate sites by surveying the sites. After comparing the ROI, two candidate sites are compared for final determination, which are Wolsong and Kori site. Some assumptions are taken into consideration due to limitations and constraints throughout performing this study. Sensitivity analysis of multi criteria decision models is performed in this study to determine the optimal site in the site selection stage. Logical Decisions software will be employed as a tool to perform this analysis. Logical Decisions software helps to formulate the preferences and then rank the alternatives. It provides clarification of the rankings and hence aids the decision makers on evaluating the alternatives, and finally draw a conclusion on the selection of the optimal site
Optimal Procedure for siting of Nuclear Power Plant
Energy Technology Data Exchange (ETDEWEB)
Aziuddin, Khairiah Binti; Park, Seo Yeon; Roh, Myung Sub [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)
2013-10-15
This study discusses on a simulation approach for sensitivity analysis of the weights of multi-criteria decision models. The simulation procedures can also be used to aid the actual decision process, particularly when the task is to select a subset of superior alternatives. This study is to identify the criteria or parameters which are sensitive to the weighting factor that can affect the results in the decision making process to determine the optimal site for nuclear power plant (NPP) site. To perform this study, we adhere to IAEA NS-R-3 and DS 433. The siting process for nuclear installation consists of site survey and site selection stages. The siting process generally consists of an investigation of a large region to select one or more candidate sites by surveying the sites. After comparing the ROI, two candidate sites are compared for final determination, which are Wolsong and Kori site. Some assumptions are taken into consideration due to limitations and constraints throughout performing this study. Sensitivity analysis of multi criteria decision models is performed in this study to determine the optimal site in the site selection stage. Logical Decisions software will be employed as a tool to perform this analysis. Logical Decisions software helps to formulate the preferences and then rank the alternatives. It provides clarification of the rankings and hence aids the decision makers on evaluating the alternatives, and finally draw a conclusion on the selection of the optimal site.
Optimal PMU location in power systems using MICA
Directory of Open Access Journals (Sweden)
Seyed Abbas Taher
2016-03-01
Full Text Available This study presented a modified imperialist competitive algorithm (MICA for optimal placement of phasor measurement units (PMUs in normal and contingency conditions of power systems. The optimal PMU placement problem is used for full network observability with the minimum number of PMUs. For this purpose, PMUs are installed in strategic buses. Efficiency of the proposed method is shown by the simulation results of IEEE 14, 30, 57, and 118-bus test systems. Results of the numerical simulation on IEEE-test systems indicated that the proposed technique provided maximum redundancy measurement and minimum request of PMUs so that the whole system could be topologically observable by installing PMUs on the minimum system buses. To verify the proposed method, the results are compared with those of some recently reported methods. When MICA is used for solving optimal PMU placement (OPP, the number of PMUs would be usually equal to or less than those of the other existing methods. Results indicated that MICA is a very fast and accurate algorithm for OPP solution.
Yang, Hang; Zhang, Yongxin; Zheng, Chenghang; Wu, Xuecheng; Chen, Linghong; Gao, Xiang; Fu, Joshua S
2018-05-10
The pollutant abatement systems are widely applied in the coal-fired power sector and the energy consumption was considered an important part of the auxiliary power. An energy consumption analysis and assessment model of pollutant abatement systems in a power unit was developed based on the dynamic parameters and technology. The energy consumption of pollutant abatement systems in a 1000 MW coal-fired power unit which meet the ultra-low emission limits and the factors of operating parameters including unit load and inlet concentration of pollutants on the operating power were analyzed. The results show that the total power consumption of the pollutant abatement systems accounted for 1.27% of the gross power generation during the monitoring period. The WFGD system consumed 67% of the rate while the SCR and ESP systems consumed 8.9% and 24.1%. The power consumption rate of pollutant abatement systems decreased with the increase of unit load and increased with the increase of the inlet concentration of pollutants. The operation adjustment was also an effective method to increase the energy efficiency. For example, the operation adjustment of slurry circulation pumps could promote the energy-saving operation of WFGD system. Implication Statement The application of pollutant abatement technologies increases the internal energy consumption of the power plant, which will lead to an increase of power generation costs. The real-time energy consumption of the different pollutant abatement systems in a typical power unit is analyzed based on the dynamic operating data. Further, the influence of different operating parameters on the operating power of the system and the possible energy-saving potential are analyzed.
Impact of Thyristors Controlled Series Capacitor Devices and Optimal Power Flow on Power Systems
Directory of Open Access Journals (Sweden)
Fatiha LAKDJA
2010-12-01
Full Text Available This paper presents an algorithm, for solving the Optimal Power Flow problem with flexible AC transmission systems (FACTS. The type of FACTS devices is used: thyristor-controlled series capacitor (TCSC. A method to determine the optimal location of thyristor controlled series compensators has been suggested. The proposed approaches have been implemented on an adapted IEEE 26 bus system. The simulation results are discussed to show the performance of the proposed algorithm and our FACTS programmer simulator technique, which are compared with TCSC and without TCSC.
Directory of Open Access Journals (Sweden)
Aida Fazliana Abdul Kadir
2014-01-01
Full Text Available This paper is an overview of some of the main issues in photovoltaic based distributed generation (PVDG. A discussion of the harmonic distortion produced by PVDG units is presented. The maximum permissible penetration level of PVDG in distribution system is also considered. The general procedures of optimal planning for PVDG placement and sizing are also explained in this paper. The result of this review shows that there are different challenges for integrating PVDG in the power systems. One of these challenges is integrated system reliability whereas the amount of power produced by renewable energy source is consistent. Thus, the high penetration of PVDG into grid can decrease the reliability of the power system network. On the other hand, power quality is considered one of the challenges of PVDG whereas the high penetration of PVDGs can lead to more harmonic propagation into the power system network. In addition to that, voltage fluctuation of the integrated PVDG and reverse power flow are two important challenges to this technology. Finally, protection of power system with integrated PVDG is one of the most critical challenges to this technology as the current protection schemes are designed for unidirectional not bidirectional power flow pattern.
Structural optimization of static power control programs of nuclear power plants with WWER-1000
International Nuclear Information System (INIS)
Kokol, E.O.
2015-01-01
The question of possibility the power control programs switching for WWER-1000 is considered. The aim of this research is to determine the best program for the power control of nuclear reactor under cyclic diurnal behavior of electrical generation, as well as the switching implementation. The considered problem of finding the best control program refers to the multicriteria optimization class of problems. Operation of the nuclear power generation system simulated using the following power control programs: with constant average temperature of transfer fluid, with constant pressure in the reactor secondary circuit, with constant temperature in input of the nuclear reactor. The target function was proposed. It consists of three normalized criteria: the burn up fraction, the damage level of fuel rod array shells, as well as changes in the power values. When simulation of the nuclear power generation system operation within the life was done, the values of the selected criteria were obtained and inserted in the target function. The minimum of three values of the target function depending on the control program at current time defined the criterion of switching of considered static power control programs for nuclear power generation system
Automated magnetic divertor design for optimal power exhaust
Energy Technology Data Exchange (ETDEWEB)
Blommaert, Maarten
2017-07-01
The so-called divertor is the standard particle and power exhaust system of nuclear fusion tokamaks. In essence, the magnetic configuration hereby 'diverts' the plasma to a specific divertor structure. The design of this divertor is still a key issue to be resolved to evolve from experimental fusion tokamaks to commercial power plants. The focus of this dissertation is on one particular design requirement: avoiding excessive heat loads on the divertor structure. The divertor design process is assisted by plasma edge transport codes that simulate the plasma and neutral particle transport in the edge of the reactor. These codes are computationally extremely demanding, not in the least due to the complex collisional processes between plasma and neutrals that lead to strong radiation sinks and macroscopic heat convection near the vessel walls. One way of improving the heat exhaust is by modifying the magnetic confinement that governs the plasma flow. In this dissertation, automated design of the magnetic configuration is pursued using adjoint based optimization methods. A simple and fast perturbation model is used to compute the magnetic field in the vacuum vessel. A stable optimal design method of the nested type is then elaborated that strictly accounts for several nonlinear design constraints and code limitations. Using appropriate cost function definitions, the heat is spread more uniformly over the high-heat load plasma-facing components in a practical design example. Furthermore, practical in-parts adjoint sensitivity calculations are presented that provide a way to an efficient optimization procedure. Results are elaborated for a fictituous JET (Joint European Torus) case. The heat load is strongly reduced by exploiting an expansion of the magnetic flux towards the solid divertor structure. Subsequently, shortcomings of the perturbation model for magnetic field calculations are discussed in comparison to a free boundary equilibrium (FBE) simulation
Automated magnetic divertor design for optimal power exhaust
International Nuclear Information System (INIS)
Blommaert, Maarten
2017-01-01
The so-called divertor is the standard particle and power exhaust system of nuclear fusion tokamaks. In essence, the magnetic configuration hereby 'diverts' the plasma to a specific divertor structure. The design of this divertor is still a key issue to be resolved to evolve from experimental fusion tokamaks to commercial power plants. The focus of this dissertation is on one particular design requirement: avoiding excessive heat loads on the divertor structure. The divertor design process is assisted by plasma edge transport codes that simulate the plasma and neutral particle transport in the edge of the reactor. These codes are computationally extremely demanding, not in the least due to the complex collisional processes between plasma and neutrals that lead to strong radiation sinks and macroscopic heat convection near the vessel walls. One way of improving the heat exhaust is by modifying the magnetic confinement that governs the plasma flow. In this dissertation, automated design of the magnetic configuration is pursued using adjoint based optimization methods. A simple and fast perturbation model is used to compute the magnetic field in the vacuum vessel. A stable optimal design method of the nested type is then elaborated that strictly accounts for several nonlinear design constraints and code limitations. Using appropriate cost function definitions, the heat is spread more uniformly over the high-heat load plasma-facing components in a practical design example. Furthermore, practical in-parts adjoint sensitivity calculations are presented that provide a way to an efficient optimization procedure. Results are elaborated for a fictituous JET (Joint European Torus) case. The heat load is strongly reduced by exploiting an expansion of the magnetic flux towards the solid divertor structure. Subsequently, shortcomings of the perturbation model for magnetic field calculations are discussed in comparison to a free boundary equilibrium (FBE) simulation. These flaws
Optimization of Power Consumption for Centrifugation Process Based on Attenuation Measurements
Salim, M. S.; Abd Malek, M. F.; Sabri, Naseer; Omar, M. Iqbal bin; Mohamed, Latifah; Juni, K. M.
2013-04-01
The main objective of this research is to produce a mathematical model that allows decreasing the electrical power consumption of centrifugation process based on attenuation measurements. The centrifugation time for desired separation efficiency may be measured to determine the power consumed of laboratory centrifuge device. The power consumption is one of several parameters that affect the system reliability and productivity. Attenuation measurements of wave propagated through blood sample during centrifugation process were used indirectly to measure the power consumption of device. A mathematical model for power consumption was derived and used to modify the speed profile of centrifuge controller. The power consumption model derived based on attenuation measurements has successfully save the power consumption of centrifugation process keeping high separation efficiency. 18kW.h monthly for 100 daily time device operation had been saved using the proposed model.
Optimization of Power Consumption for Centrifugation Process Based on Attenuation Measurements
International Nuclear Information System (INIS)
Salim, M S; Iqbal bin Omar, M; Malek, M F Abd; Mohamed, Latifah; Sabri, Naseer; Juni, K M
2013-01-01
The main objective of this research is to produce a mathematical model that allows decreasing the electrical power consumption of centrifugation process based on attenuation measurements. The centrifugation time for desired separation efficiency may be measured to determine the power consumed of laboratory centrifuge device. The power consumption is one of several parameters that affect the system reliability and productivity. Attenuation measurements of wave propagated through blood sample during centrifugation process were used indirectly to measure the power consumption of device. A mathematical model for power consumption was derived and used to modify the speed profile of centrifuge controller. The power consumption model derived based on attenuation measurements has successfully save the power consumption of centrifugation process keeping high separation efficiency. 18kW.h monthly for 100 daily time device operation had been saved using the proposed model.
International Nuclear Information System (INIS)
Noori Khajavi, M.; Menhaj, M.B.; Ghofrani, M.B.
2000-01-01
Nuclear power reactors are, in nature nonlinear and time varying. These characteristics must be considered, if large power variations occur in their working regime. In this paper a robust optimal self-tuning regulator for regulating the power of a nuclear reactor has been designed and simulated. The proposed controller is capable of regulating power levels in a wide power range (10% to 100% power levels). The controller achieves a fast and good transient response. The simulation results show that the proposed controller outperforms the fixed optimal control recently cited in the literature for nuclear power plants
A modified teaching–learning based optimization for multi-objective optimal power flow problem
International Nuclear Information System (INIS)
Shabanpour-Haghighi, Amin; Seifi, Ali Reza; Niknam, Taher
2014-01-01
Highlights: • A new modified teaching–learning based algorithm is proposed. • A self-adaptive wavelet mutation strategy is used to enhance the performance. • To avoid reaching a large repository size, a fuzzy clustering technique is used. • An efficiently smart population selection is utilized. • Simulations show the superiority of this algorithm compared with other ones. - Abstract: In this paper, a modified teaching–learning based optimization algorithm is analyzed to solve the multi-objective optimal power flow problem considering the total fuel cost and total emission of the units. The modified phase of the optimization algorithm utilizes a self-adapting wavelet mutation strategy. Moreover, a fuzzy clustering technique is proposed to avoid extremely large repository size besides a smart population selection for the next iteration. These techniques make the algorithm searching a larger space to find the optimal solutions while speed of the convergence remains good. The IEEE 30-Bus and 57-Bus systems are used to illustrate performance of the proposed algorithm and results are compared with those in literatures. It is verified that the proposed approach has better performance over other techniques
DEFF Research Database (Denmark)
Ding, Yi; Goel, Lalit; Wang, Peng
2012-01-01
cost of the system will also increase. The reserve structure of a MSS should be determined based on striking a balance between the required reliability and the reserve cost. The objective of reserve management for a MSS is to schedule the reserve at the minimum system reserve cost while maintaining......Electric power generating systems are typical examples of multi-state systems (MSS). Sufficient reserve is critically important for maintaining generating system reliabilities. The reliability of a system can be increased by increasing the reserve capacity, noting that at the same time the reserve...... the required level of supply reliability to its customers. In previous research, Genetic Algorithm (GA) has been used to solve most reliability optimization problems. However, the GA is not very computationally efficient in some cases. In this chapter a new heuristic optimization technique—the particle swarm...
Optimization-based reactive power control in HVDC-connected wind power plants
Schönleber, Kevin; Collados Rodríguez, Carlos; Teixeira Pinto, Rodrigo; Ratés Palau, Sergi; Gomis Bellmunt, Oriol
2017-01-01
One application of high–voltage dc (HVdc) systems is the connection of remotely located offshore wind power plants (WPPs). In these systems, the offshore WPP grid and the synchronous main grid operate in decoupled mode, and the onshore HVdc converter fulfills the grid code requirements of the main grid. Thus, the offshore grid can be operated independently during normal conditions by the offshore HVdc converter and the connected wind turbines. In general, it is well known that optimized react...
International Nuclear Information System (INIS)
Zhu, Yonghua; Jin, Xinqiao; Du, Zhimin; Fang, Xing
2015-01-01
The variable refrigerant flow (VRF) and variable air volume (VAV) combined air conditioning system can solve the problem of the VRF system in outdoor air ventilation while taking advantage of its high part load energy efficiency. Energy performance of the combined air conditioning system can also be optimized by joint control of both the VRF and the VAV parts. A model-based online optimal control strategy for the combined air conditioning system is presented. Simplified adaptive models of major components of the combined air conditioning system are firstly developed for predicting system performances. And a cost function in terms of energy consumption and thermal comfort is constructed. Genetic algorithm is used to search for the optimal control sets. The optimal control strategy is tested and evaluated through two case studies based on the simulation platform. Results show that the optimal strategy can effectively reduce energy consumption of the combined air conditioning system while maintaining acceptable thermal comfort. - Highlights: • A VRF and VAV combined system is proposed. • A model-based online optimal control strategy is proposed for the combined system. • The strategy can reduce energy consumption without sacrificing thermal comfort. • Novel simplified adaptive models are firstly developed for the VRF system
Roselyn, J. Preetha; Devaraj, D.; Dash, Subhransu Sekhar
2013-11-01
Voltage stability is an important issue in the planning and operation of deregulated power systems. The voltage stability problems is a most challenging one for the system operators in deregulated power systems because of the intense use of transmission line capabilities and poor regulation in market environment. This article addresses the congestion management problem avoiding offline transmission capacity limits related to voltage stability by considering Voltage Security Constrained Optimal Power Flow (VSCOPF) problem in deregulated environment. This article presents the application of Multi Objective Differential Evolution (MODE) algorithm to solve the VSCOPF problem in new competitive power systems. The maximum of L-index of the load buses is taken as the indicator of voltage stability and is incorporated in the Optimal Power Flow (OPF) problem. The proposed method in hybrid power market which also gives solutions to voltage stability problems by considering the generation rescheduling cost and load shedding cost which relieves the congestion problem in deregulated environment. The buses for load shedding are selected based on the minimum eigen value of Jacobian with respect to the load shed. In the proposed approach, real power settings of generators in base case and contingency cases, generator bus voltage magnitudes, real and reactive power demands of selected load buses using sensitivity analysis are taken as the control variables and are represented as the combination of floating point numbers and integers. DE/randSF/1/bin strategy scheme of differential evolution with self-tuned parameter which employs binomial crossover and difference vector based mutation is used for the VSCOPF problem. A fuzzy based mechanism is employed to get the best compromise solution from the pareto front to aid the decision maker. The proposed VSCOPF planning model is implemented on IEEE 30-bus system, IEEE 57 bus practical system and IEEE 118 bus system. The pareto optimal
Optimization of power distribution networks; Optimierung von Energieverteilungsnetzen
Energy Technology Data Exchange (ETDEWEB)
Casteren, J. van [Digsilent GmbH (Netherlands); Chalmers Univ. of Technology, Goeteborg (Sweden)
2000-03-01
In a competition-oriented power market the optimization of distribution networks is more and more becoming a search for minimum investment and operating cost where all relevant cost factors should be taken into account. A so far neglected factor is the expectation of reliability-related cost. A new analytical calculation method permits flexible, realistic estimation of interruption costs to be expected. (orig.) [German] In einem wettbewerbsorientierten Strom-Markt wird die Optimierung der Verteilungsnetze mehr und mehr zu einer Suche nach den minimalen Investitions- und Betriebskosten, wobei moeglichst alle relevanten Kostenfaktoren beruecksichtigt werden muessen. Ein bisher vernachlaessigter Faktor ist dabei die Erwartung der zuverlaessigkeitsbedingten Kosten. Ein neues analytisches Berechnungsverfahren erlaubt nun flexibel eine realistische Abschaetzung der zu erwarteten Unterbrechungskosten. (orig.)
Directory of Open Access Journals (Sweden)
Dharmbir Prasad
2016-03-01
Full Text Available In this paper, symbiotic organisms search (SOS algorithm is proposed for the solution of optimal power flow (OPF problem of power system equipped with flexible ac transmission systems (FACTS devices. Inspired by interaction between organisms in ecosystem, SOS algorithm is a recent population based algorithm which does not require any algorithm specific control parameters unlike other algorithms. The performance of the proposed SOS algorithm is tested on the modified IEEE-30 bus and IEEE-57 bus test systems incorporating two types of FACTS devices, namely, thyristor controlled series capacitor and thyristor controlled phase shifter at fixed locations. The OPF problem of the present work is formulated with four different objective functions viz. (a fuel cost minimization, (b transmission active power loss minimization, (c emission reduction and (d minimization of combined economic and environmental cost. The simulation results exhibit the potential of the proposed SOS algorithm and demonstrate its effectiveness for solving the OPF problem of power system incorporating FACTS devices over the other evolutionary optimization techniques that surfaced in the recent state-of-the-art literature.
Srikantha, Pirathayini
Today's electric grid is rapidly evolving to provision for heterogeneous system components (e.g. intermittent generation, electric vehicles, storage devices, etc.) while catering to diverse consumer power demand patterns. In order to accommodate this changing landscape, the widespread integration of cyber communication with physical components can be witnessed in all tenets of the modern power grid. This ubiquitous connectivity provides an elevated level of awareness and decision-making ability to system operators. Moreover, devices that were typically passive in the traditional grid are now `smarter' as these can respond to remote signals, learn about local conditions and even make their own actuation decisions if necessary. These advantages can be leveraged to reap unprecedented long-term benefits that include sustainable, efficient and economical power grid operations. Furthermore, challenges introduced by emerging trends in the grid such as high penetration of distributed energy sources, rising power demands, deregulations and cyber-security concerns due to vulnerabilities in standard communication protocols can be overcome by tapping onto the active nature of modern power grid components. In this thesis, distributed constructs in optimization and game theory are utilized to design the seamless real-time integration of a large number of heterogeneous power components such as distributed energy sources with highly fluctuating generation capacities and flexible power consumers with varying demand patterns to achieve optimal operations across multiple levels of hierarchy in the power grid. Specifically, advanced data acquisition, cloud analytics (such as prediction), control and storage systems are leveraged to promote sustainable and economical grid operations while ensuring that physical network, generation and consumer comfort requirements are met. Moreover, privacy and security considerations are incorporated into the core of the proposed designs and these
Optimal power flow application issues in the Pool paradigm
International Nuclear Information System (INIS)
Gross, G.; Bompard, E.
2004-01-01
This paper focuses on the application of the Optimal Power Flow (OPF) to competitive markets. Since the OPF is a central decision-making tool its application to the more decentralized decision-making in the competitive electricity markets requires considerable care. There are some intrinsic challenges associated with the effective OPF application in the competitive environment due to the inherent characteristics of the OPF formulation. Two such characteristics are the flatness of the optimum surface and the consequent continuum associated with the optimum. In addition to these OPF structural characteristics, the level of authority vested in the central decision-making entity has major ramifications. These factors have wide ranging economic impacts, whose implications are very pronounced due to the fact that, unlike in the old vertically integrated utility environment, various market players are affected differently. The effects include price volatility, financial health of various players and the integrity of the market itself. We apply appropriate metrics to evaluate market efficiency and how the various players fare. We study the impacts of OPF applications in the Pool paradigm, with both supply and demand side explicitly modeled, and provide extensive numerical results on systems based on IEEE 30-bus and 118-bus networks. The results show the variability of nodal prices and the skew possible in different 'optimal' allocations among competing suppliers. Such variability in the results may lead to serious disputes among the players and the central decision-making authority. Directions for future research are discussed. (author)
Optimizing power system investments and resilience against attacks
International Nuclear Information System (INIS)
Fang, Yiping; Sansavini, Giovanni
2017-01-01
This paper studies the combination of capacity expansion and switch installation in electric systems that ensures optimum performance under nominal operations and attacks. The planner–attacker–defender model is adopted to develop decisions that minimize investment and operating costs, and functionality loss after attacks. The model bridges long-term system planning for transmission expansion and short-term switching operations in reaction to attacks. The mixed-integer optimization is solved by decomposition via two-layer cutting plane algorithm. Numerical results on an IEEE system shows that small investments in transmission line switching enhance resilience by responding to disruptions via system reconfiguration. Sensitivity analyses show that transmission planning under the assumption of small-scale attacks provides the most robust strategy, i.e. the minimum-regret planning, if many constraints and limited investment budget affect the planning. On the other hand, the assumption of large-scale attacks provides the most robust strategy if the planning process involves large flexibility and budget. - Highlights: • Investment optimization in power systems under attacks is presented. • Capacity expansion and switch installation for system reconfiguration are combined. • The problem is solved by decomposition via two-layer cutting plane algorithm. • Small investments in switch installation enhance resilience by response to attacks. • Sensitivity analyses identify robust planning against different attack scenarios.
Directory of Open Access Journals (Sweden)
Aouss Gabash
2016-02-01
Full Text Available It has recently been shown that using battery storage systems (BSSs to provide reactive power provision in a medium-voltage (MV active distribution network (ADN with embedded wind stations (WSs can lead to a huge amount of reverse power to an upstream transmission network (TN. However, unity power factors (PFs of WSs were assumed in those studies to analyze the potential of BSSs. Therefore, in this paper (Part-I, we aim to further explore the pure reactive power potential of WSs (i.e., without BSSs by investigating the issue of variable reverse power flow under different limits on PFs in an electricity market model. The main contributions of this work are summarized as follows: (1 Introducing the reactive power capability of WSs in the optimization model of the active-reactive optimal power flow (A-R-OPF and highlighting the benefits/impacts under different limits on PFs. (2 Investigating the impacts of different agreements for variable reverse power flow on the operation of an ADN under different demand scenarios. (3 Derivation of the function of reactive energy losses in the grid with an equivalent-π circuit and comparing its value with active energy losses. (4 Balancing the energy curtailment of wind generation, active-reactive energy losses in the grid and active-reactive energy import-export by a meter-based method. In Part-II, the potential of the developed model is studied through analyzing an electricity market model and a 41-bus network with different locations of WSs.
Optimizing the robustness of electrical power systems against cascading failures.
Zhang, Yingrui; Yağan, Osman
2016-06-21
Electrical power systems are one of the most important infrastructures that support our society. However, their vulnerabilities have raised great concern recently due to several large-scale blackouts around the world. In this paper, we investigate the robustness of power systems against cascading failures initiated by a random attack. This is done under a simple yet useful model based on global and equal redistribution of load upon failures. We provide a comprehensive understanding of system robustness under this model by (i) deriving an expression for the final system size as a function of the size of initial attacks; (ii) deriving the critical attack size after which system breaks down completely; (iii) showing that complete system breakdown takes place through a first-order (i.e., discontinuous) transition in terms of the attack size; and (iv) establishing the optimal load-capacity distribution that maximizes robustness. In particular, we show that robustness is maximized when the difference between the capacity and initial load is the same for all lines; i.e., when all lines have the same redundant space regardless of their initial load. This is in contrast with the intuitive and commonly used setting where capacity of a line is a fixed factor of its initial load.
Random Sequence for Optimal Low-Power Laser Generated Ultrasound
Vangi, D.; Virga, A.; Gulino, M. S.
2017-08-01
Low-power laser generated ultrasounds are lately gaining importance in the research world, thanks to the possibility of investigating a mechanical component structural integrity through a non-contact and Non-Destructive Testing (NDT) procedure. The ultrasounds are, however, very low in amplitude, making it necessary to use pre-processing and post-processing operations on the signals to detect them. The cross-correlation technique is used in this work, meaning that a random signal must be used as laser input. For this purpose, a highly random and simple-to-create code called T sequence, capable of enhancing the ultrasound detectability, is introduced (not previously available at the state of the art). Several important parameters which characterize the T sequence can influence the process: the number of pulses Npulses , the pulse duration δ and the distance between pulses dpulses . A Finite Element FE model of a 3 mm steel disk has been initially developed to analytically study the longitudinal ultrasound generation mechanism and the obtainable outputs. Later, experimental tests have shown that the T sequence is highly flexible for ultrasound detection purposes, making it optimal to use high Npulses and δ but low dpulses . In the end, apart from describing all phenomena that arise in the low-power laser generation process, the results of this study are also important for setting up an effective NDT procedure using this technology.
Multi-Period Portfolio Optimization of Power Generation Assets
Directory of Open Access Journals (Sweden)
Barbara Glensk
2013-01-01
Full Text Available The liberalization and deregulation of the energy industry in the past decades have been significantly affected by changes in the strategies of energy firms. The traditionally used approach of cost minimization was no longer sufficient, risk and market behavior could no longer be ignored and the need for more appropriate optimization methods for uncertain environments was increased. Meanvariance portfolio (MVP theory is one of the more advanced financial methods that has been successfully applied to the energy sector. Unfortunately, this static approach is inadequate for studying multi-stage investment decision problems. The methodology proposed in this paper considering power generation assets is based on the model introduced by Mulvey, who suggests a reallocation approach using the analysis of various scenarios. The adoption of this methodology to power generation assets allows us to capture the impact of variations in the economic and technical parameters considered. The results of our study show that the application of a model for selection of multi-period portfolio can indeed improve the decision making process. Especially for the case of adding new investments to the portfolio mix, this rebalancing model captures new entries very well. (original abstract
International Nuclear Information System (INIS)
Pan, Ming; Aziz, Farah; Li, Baohong; Perry, Simon; Zhang, Nan; Bulatov, Igor; Smith, Robin
2016-01-01
Highlights: • A new approach is proposed for retrofitting NGCC power plants with CO2 capture. • HTI techniques are developed for improving heat recovery in NGCC power plants. • EGR techniques are developed to increase the process overall energy efficiency. • The proposed methods are efficient for practical application. - Abstract: Around 21% of the world’s power production is based on natural gas. Energy production is considered to be the significant sources of carbon dioxide (CO_2) emissions. This has a significant effect on the global warming. Improving power plant efficiency and adding a CO_2 capture unit into power plants, have been suggested to be a promising countermeasure against global warming. This paper presents a new insight to the application of energy efficient technologies in retrofitting natural gas combined cycle (NGCC) power plants with CO_2 capture. High fidelity models of a 420 MW NGCC power plant and a CO_2 capture plant with CO_2 compression train have been built and integrated for 90% capture level. These models have been then validated by comparisons with practical operating data and literature results. The novelty of the paper is to propose optimal retrofitting strategies to minimize the efficiency penalty caused by integrating carbon capture units into the power plant, including (1) implementing heat transfer intensification techniques to increase energy saving in the heat recovery steam generator (HRSG) of the power plant; (2) extracting suitable steam from the HRSG to supply the heat required by the capture process, thus on external heat is purchased; (3) employing exhaust gas recirculation (EGR) to increase the overall energy efficiency of the integrated process, which can benefit both power plant (e.g. increasing power plant efficiency) and capture process (e.g. reducing heat demands). Compared with the base case without using any integrating and retrofitting strategies, the optimal solution based on the proposed approaches
Methods and tools for analysis and optimization of power plants
Energy Technology Data Exchange (ETDEWEB)
Assadi, Mohsen
2000-09-01
The most noticeable advantage of the introduction of the computer-aided tools in the field of power generation, has been the ability to study the plant's performance prior to the construction phase. The results of these studies have made it possible to change and adjust the plant layout to match the pre-defined requirements. Further development of computers in recent years has opened up for implementation of new features in the existing tools and also for the development of new tools for specific applications, like thermodynamic and economic optimization, prediction of the remaining component life time, and fault diagnostics, resulting in improvement of the plant's performance, availability and reliability. The most common tools for pre-design studies are heat and mass balance programs. Further thermodynamic and economic optimization of plant layouts, generated by the heat and mass balance programs, can be accomplished by using pinch programs, exergy analysis and thermoeconomics. Surveillance and fault diagnostics of existing systems can be performed by using tools like condition monitoring systems and artificial neural networks. The increased number of tools and their various construction and application areas make the choice of the most adequate tool for a certain application difficult. In this thesis the development of different categories of tools and techniques, and their application area are reviewed and presented. Case studies on both existing and theoretical power plant layouts have been performed using different commercially available tools to illuminate their advantages and shortcomings. The development of power plant technology and the requirements for new tools and measurement systems have been briefly reviewed. This thesis contains also programming techniques and calculation methods concerning part-load calculations using local linearization, which has been implemented in an inhouse heat and mass balance program developed by the author
Directory of Open Access Journals (Sweden)
Shi Chen-guang
2014-08-01
Full Text Available A novel optimal power allocation algorithm for radar network systems is proposed for Low Probability of Intercept (LPI technology in modern electronic warfare. The algorithm is based on the LPI optimization. First, the Schleher intercept factor for a radar network is derived, and then the Schleher intercept factor is minimized by optimizing the transmission power allocation among netted radars in the network to guarantee target-tracking performance. Furthermore, the Nonlinear Programming Genetic Algorithm (NPGA is used to solve the resulting nonconvex, nonlinear, and constrained optimization problem. Numerical simulation results show the effectiveness of the proposed algorithm.
Apribowo, Chico Hermanu Brillianto; Ibrahim, Muhammad Hamka; Wicaksono, F. X. Rian
2018-02-01
The growing burden of the load and the complexity of the power system has had an impact on the need for optimization of power system operation. Optimal power flow (OPF) with optimal location placement and rating of thyristor controlled series capacitor (TCSC) is an effective solution used to determine the economic cost of operating the plant and regulate the power flow in the power system. The purpose of this study is to minimize the total cost of generation by placing the location and the optimal rating of TCSC using genetic algorithm-design of experiment techniques (GA-DOE). Simulation on Java-Bali system 500 kV with the amount of TCSC used by 5 compensator, the proposed method can reduce the generation cost by 0.89% compared to OPF without using TCSC.
Amole, Carolyn D; Brisebois, Catherine; Essajee, Shaffiq; Koehler, Erin; Levin, Andrew D; Moore, Meredith C; Brown Ripin, David H; Sickler, Joanna J; Singh, Inder R
2011-08-01
Over the last decade, increased funding to support HIV treatment programs has enabled millions of new patients in developing countries to access the medications they need. Today, although demand for antiretrovirals continues to grow, the financial crisis has severely constrained funding leaving countries with difficult choices on program prioritization. Product optimization is one solution countries can pursue to continue to improve patient care while also uncovering savings that can be used for further scale up or other health system needs. Program managers can make procurement decisions that actually reduce program costs by considering additional factors beyond World Health Organization guidelines when making procurement decisions. These include in-country product availability, convenience, price, and logistics such as supply chain implications and laboratory testing requirements. Three immediate product selection opportunities in the HIV space include using boosted atazanavir in place of lopinovir for second-line therapy, lamivudine instead of emtricitabine in both first-line and second-line therapy, and tenofovir + lamivudine over abacavir + didanosine in second-line therapy. If these 3 opportunities were broadly implemented in sub-Saharan Africa and India today, approximately $300 million of savings would be realized over the next 5 years, enabling hundreds of thousands of additional patients to be treated. Although the discussion herein is specific to antriretrovirals, the principles of product selection are generalizable to diseases with multiple treatment options and fungible commodity procurement. Identifying and implementing approaches to overcome health system inefficiencies will help sustain and may expand quality care in resource-limited settings.
Directory of Open Access Journals (Sweden)
Huan-huan Li
2015-01-01
Full Text Available Wind power has the characteristics of randomness and intermittence, which influences power system safety and stable operation. To alleviate the effect of wind power grid connection and improve power system’s wind power consumptive capability, this paper took emission trading and energy storage system into consideration and built an optimization model for thermal-wind power system and energy storage systems collaborative scheduling. A simulation based on 10 thermal units and wind farms with 2800 MW installed capacity verified the correctness of the models put forward by this paper. According to the simulation results, the introduction of carbon emission trading can improve wind power consumptive capability and cut down the average coal consumption per unit of power. The introduction of energy storage system can smooth wind power output curve and suppress power fluctuations. The optimization effects achieve the best when both of carbon emission trading and energy storage system work at the same time.
International Nuclear Information System (INIS)
Mohamed, A.A.E.S.
2013-01-01
Capacitors are widely installed in distribution systems for reactive power compensation to achieve power and energy loss reduction, voltage regulation and system capacity release. The extent of these benefits depends greatly on how the capacitors are placed on the system. The problem of how to place capacitors on the system such that these benefits are achieved and maximized against the cost associated with the capacitor placement is termed the general capacitor placement problem. The capacitor placement problem has been formulated as the maximization of the savings resulted from reduction in both peak power and energy losses considering capacitor installation cost and maintaining the buses voltage within acceptable limits. After an appropriate analysis, the optimization problem was formulated in a quadratic form. For solving capacitor placement a new combinatorial heuristic and quadratic programming technique has been presented and applied in the MATLAB software. The proposed strategy was applied on two different radial distribution feeders. The results have been compared with previous works. The comparison showed the validity and the effectiveness of this strategy. Secondly, two artificial intelligence techniques for predicting the capacitor switching state in radial distribution feeders have been investigated; one is based on basis Radial Basis Neural Network (RBNN) and the other is based on Adaptive Neuro-Fuzzy Inference System (ANFIS). The ANFIS technique gives better results with a minimum total error compared to RBNN. The learning duration of ANFIS was very short than the neural network case. It implied that ANFIS reaches to the target faster than neural network. Thirdly, an artificial intelligence (RBNN) approach for estimation of transient overvoltage during capacitor switching has been studied. The artificial intelligence approach estimated the transient overvoltages with a minimum error in a short computational time. Finally, a capacitor switching
The Optimal Dispatch of a Power System Containing Virtual Power Plants under Fog and Haze Weather
Directory of Open Access Journals (Sweden)
Yajing Gao
2016-01-01
Full Text Available With the growing influence of fog and haze (F-H weather and the rapid development of distributed energy resources (DERs and smart grids, the concept of the virtual power plant (VPP employed in this study would help to solve the dispatch problem caused by multiple DERs connected to the power grid. The effects of F-H weather on photovoltaic output forecast, load forecast and power system dispatch are discussed according to real case data. The wavelet neural network (WNN model was employed to predict photovoltaic output and load, considering F-H weather, based on the idea of “similar days of F-H”. The multi-objective optimal dispatch model of a power system adopted in this paper contains several VPPs and conventional power plants, under F-H weather, and the mixed integer linear programming (MILP and the Yalmip toolbox of MATLAB were adopted to solve the dispatch model. The analysis of the results from a case study proves the validity and feasibility of the model and the algorithms.
International Nuclear Information System (INIS)
Anon.
1983-01-01
The article is an interview with Glenn Bjorklund, Vice President of SCalEd (Southern California Edison). The variations in Californian power demand and public electricity consumption habits are explained, together with types of power source used in electricity production. Questions are posed concerning SCalEd's energy saving strategy. The political implications of electricity charge changes are discussed. The planned energy resources for 1982-1992 are given with nuclear power being the largest contributor. (H.J.P./G.T.H.)
Families of optimal thermodynamic solutions for combined cycle gas turbine (CCGT) power plants
International Nuclear Information System (INIS)
Godoy, E.; Scenna, N.J.; Benz, S.J.
2010-01-01
Optimal designs of a CCGT power plant characterized by maximum second law efficiency values are determined for a wide range of power demands and different values of the available heat transfer area. These thermodynamic optimal solutions are found within a feasible operation region by means of a non-linear mathematical programming (NLP) model, where decision variables (i.e. transfer areas, power production, mass flow rates, temperatures and pressures) can vary freely. Technical relationships among them are used to systematize optimal values of design and operative variables of a CCGT power plant into optimal solution sets, named here as optimal solution families. From an operative and design point of view, the families of optimal solutions let knowing in advance optimal values of the CCGT variables when facing changes of power demand or adjusting the design to an available heat transfer area.
International Nuclear Information System (INIS)
Pautard, Eric
2012-01-01
From 'saving energy' awareness campaign to financial incentives for efficient technologies, from rationing to energy efficiency commitment, from monopolistic public management to compelling involvement of the electricity-supply market, from economic stakes to ecological issues, Demand-Side Management policies have changed over time. This paper analyzes this historical background in order to examine the effects of the electricity market deregulation in France and United Kingdom
International Nuclear Information System (INIS)
Luo, Xianglong; Zhang, Bingjian; Chen, Ying; Mo, Songping
2013-01-01
Highlights: ► We develop a systematic programming methodology to address equipment failure. ► We classify different operation conditions into real periods and virtual periods. ► The formulated MILP models guarantee cost reduction and enough operation safety. ► The consideration of reserving operation redundancy is effective. - Abstract: One or more interconnected steam power plants (SPPs) are constructed in a petrochemical complex to supply utility energy to the process. To avoid large economic penalties or process shutdowns, these SPPs should be flexible and reliable enough to meet the process energy requirement under varying conditions. Unexpected utility equipment failure is inevitable and difficult to be predicted. Most of the conventional methods are based on the assumption that SPPs do not experience any kind of equipment failure. Unfortunately, a process shutdown cannot be avoided when equipment fails unexpectedly. In this paper, a systematic methodology is presented to minimize the total cost under normal conditions while reserving enough flexibility and safety for unexpected equipment failure conditions. The proposed method transforms the different conditions into real periods to indicate normal scenarios and virtual periods to indicate unexpected equipment failure scenarios. The optimization strategy incorporating various operation redundancy scheduling, the transition constraints from equipment failure conditions to normal conditions, and the boiler load increase behavior modeling are presented to save cost and guarantee operation safety. A detailed industrial case study shows that the proposed systematic methodology is effective and practical in coping with equipment failure conditions with only few additional cost penalties
Energy Technology Data Exchange (ETDEWEB)
Didriksen, H.; Sandvig Nielsen, J.; Weel Hansen, M.
2001-06-01
The aim of the project is to present a procedure to optimize existing drying processes. The optimization deals with energy consumption, capacity utilization and product quality. Other factors can also be included in the optimization, e.g. minimization of volume of discharged air. The optimization of existing drying processes will use calculation tool based on a mathematical simulation model for the process to calculate the most optimum operation situation on the basis of given conditions. In the project mathematical models have been developed precisely with this aim. The calculation tools have been developed with a user interface so that the tools can be used by technical staff in industrial companies and by consultants. The project also illustrates control of drying processes. Based on the developed models, the effect of using different types of control strategies by means of model simulations is illustrated. Three types of drying processes are treated: drum dryers, disc dryers and drying chambers. The work with the development of the simulation models has been very central in the project, as these have to be the basis for the optimization of the processes. The work is based on a large amount of information from academical literature and knowledge and experience about modelling thermal processes at dk-TEKNIK. The models constitute the core in the simulation programmes. The models describe the most important physical effects in connection with mass and energy transfer and transport under the drying for the three treated drying technologies. (EHS)
Optimization of the power distribution in a large power reactor core
International Nuclear Information System (INIS)
Emel'yanov, I.Ya.; Nazaryan, V.G.; Postnikov, V.V.
1978-01-01
The reactor power distribution optimization problem is solved for the case of the RBMK-1000 reactor. The algorithm is written in terms of the linear programming method. The algorithm rests on two assumptions: 1) the relative power change of each fuel assembly is a linear function of reactivity increment caused by displacement of a regulating rod; 2) the change is an additive value. The algorithm is written in ALGOL for the BESM-6 computer. The optimum reactivity gain for the RBMK reactor has proved to equal the reactivity of 35-40 control rods. The results obtained confirm the validity of the assumptions. It is noted that the total computation time on the BESM-6 can be reduced to 20 min
Directory of Open Access Journals (Sweden)
Reza Sirjani
2018-03-01
Full Text Available Solar energy is a source of free, clean energy which avoids the destructive effects on the environment that have long been caused by power generation. Solar energy technology rivals fossil fuels, and its development has increased recently. Photovoltaic (PV solar farms can only produce active power during the day, while at night, they are completely idle. At the same time, though, active power should be supported by reactive power. Reactive power compensation in power systems improves power quality and stability. The use during the night of a PV solar farm inverter as a static synchronous compensator (or PV-STATCOM device has recently been proposed which can improve system performance and increase the utility of a PV solar farm. In this paper, a method for optimal PV-STATCOM placement and sizing is proposed using empirical data. Considering the objectives of power loss and cost minimization as well as voltage improvement, two sub-problems of placement and sizing, respectively, are solved by a power loss index and adaptive particle swarm optimization (APSO. Test results show that APSO not only performs better in finding optimal solutions but also converges faster compared with bee colony optimization (BCO and lightening search algorithm (LSA. Installation of a PV solar farm, STATCOM, and PV-STATCOM in a system are each evaluated in terms of efficiency and cost.
International Nuclear Information System (INIS)
Choi, M.; Glicksman, L.R.
1979-02-01
This study determined the cost of dry cooling compared to the conventional cooling methods. Also, the savings by using wet/dry instead of all-dry cooling were determined. A total optimization was performed for power plants with dry cooling tower systems using metal-finned-tube heat exchangers and surface condensers. The optimization minimizes the power production cost. The program optimizes the design of the heat exchanger and its air and water flow rates. In the base case study, the method of replacing lost capacity assumes the use of gas turbines. As a result of using dry cooling towers in an 800 MWe fossil plant, the incremental costs with the use of high back pressure turbine and conventional turbine over all-wet cooling are 11 and 15%, respectively. For a 1200 MWe nuclear plant, these are 22 and 25%, respectively. Since the method of making up lost capacity depends on the situation of a utility, considerable effort has been placed on testing the effects of using different methods of replacing lost capacity at high ambient temperatures by purchased energy. The results indicate that the optimization is very sensitive to the method of making up lost capacity. It is, therefore, important to do an accurate representation of all possible methods of making up capacity loss when optimizating power plants with dry cooling towers. A solution for the problem of losing generation capability by a power plant due to the use of a dry cooling tower is to supplement the dry tower during the hours of peak ambient temperatures by a wet tower. A separate wet/dry cooling tower system with series tower arrangement was considered in this study, and proved to be an economic choice over all-dry cooling where some water is available but supplies are insufficient for a totally evaporative cooling tower
The design of optimal electric power demand management contracts
Fahrioglu, Murat
1999-11-01
Our society derives a quantifiable benefit from electric power. In particular, forced outages or blackouts have enormous consequences on society, one of which is loss of economic surplus. Electric utilities try to provide reliable supply of electric power to their customers. Maximum customer benefit derives from minimum cost and sufficient supply availability. Customers willing to share in "availability risk" can derive further benefit by participating in controlled outage programs. Specifically, whenever utilities foresee dangerous loading patterns, there is a need for a rapid reduction in demand either system-wide or at specific locations. The utility needs to get relief in order to solve its problems quickly and efficiently. This relief can come from customers who agree to curtail their loads upon request in exchange for an incentive fee. This thesis shows how utilities can get efficient load relief while maximizing their economic benefit. This work also shows how estimated customer cost functions can be calibrated, using existing utility data, to help in designing efficient demand management contracts. In order to design such contracts, optimal mechanism design is adopted from "Game Theory" and applied to the interaction between a utility and its customers. The idea behind mechanism design is to design an incentive structure that encourages customers to sign up for the right contract and reveal their true value of power. If a utility has demand management contracts with customers at critical locations, most operational problems can be solved efficiently. This thesis illustrates how locational attributes of customers incorporated into demand management contract design can have a significant impact in solving system problems. This kind of demand management contracts can also be used by an Independent System Operator (ISO). During times of congestion a loss of economic surplus occurs. When the market is too slow or cannot help relieve congestion, demand management
Power Grid Construction Project Portfolio Optimization Based on Bi-level programming model
Zhao, Erdong; Li, Shangqi
2017-08-01
As the main body of power grid operation, county-level power supply enterprises undertake an important emission to guarantee the security of power grid operation and safeguard social power using order. The optimization of grid construction projects has been a key issue of power supply capacity and service level of grid enterprises. According to the actual situation of power grid construction project optimization of county-level power enterprises, on the basis of qualitative analysis of the projects, this paper builds a Bi-level programming model based on quantitative analysis. The upper layer of the model is the target restriction of the optimal portfolio; the lower layer of the model is enterprises’ financial restrictions on the size of the enterprise project portfolio. Finally, using a real example to illustrate operation proceeding and the optimization result of the model. Through qualitative analysis and quantitative analysis, the bi-level programming model improves the accuracy and normative standardization of power grid enterprises projects.
Directory of Open Access Journals (Sweden)
Suresh Chintalapudi Venkata
2015-09-01
Full Text Available In this paper a novel non-linear optimization problem is formulated to maximize the social welfare in restructured environment with generalized unified power flow controller (GUPFC. This paper presents a methodology to optimally allocate the reactive power by minimizing voltage deviation at load buses and total transmission power losses so as to maximize the social welfare. The conventional active power generation cost function is modified by combining costs of reactive power generated by the generators, shunt capacitors and total power losses to it. The formulated objectives are optimized individually and simultaneously as multi-objective optimization problem, while satisfying equality, in-equality, practical and device operational constraints. A new optimization method, based on two stage initialization and random distribution processes is proposed to test the effectiveness of the proposed approach on IEEE-30 bus system, and the detailed analysis is carried out.
International Nuclear Information System (INIS)
Shengjun, Zhang; Huaixin, Wang; Tao, Guo
2011-01-01
Research highlights: → We conduct the thermodynamic and economic performance comparison of the fluids in both subcritical ORC and transcritical power cycle. → We perform parameter optimization based on five indicators. → The optimum operation parameters and working fluids are not the same for different indicators. → The LEC value is used as the determining factor for fluids screening. → The transcritical power cycle with R125 as the working fluid was a cost-effective approach. - Abstract: Organic Rankine Cycle (ORC) is a promising technology for converting the low-grade energy to electricity. This paper presents an investigation on the parameter optimization and performance comparison of the fluids in subcritical ORC and transcritical power cycle in low-temperature (i.e. 80-100 o C) binary geothermal power system. The optimization procedure was conducted with a simulation program written in Matlab using five indicators: thermal efficiency, exergy efficiency, recovery efficiency, heat exchanger area per unit power output (APR) and the levelized energy cost (LEC). With the given heat source and heat sink conditions, performances of the working fluids were evaluated and compared under their optimized internal operation parameters. The optimum cycle design and the corresponding operation parameters were provided simultaneously. The results indicate that the choice of working fluid varies the objective function and the value of the optimized operation parameters are not all the same for different indicators. R123 in subcritical ORC system yields the highest thermal efficiency and exergy efficiency of 11.1% and 54.1%, respectively. Although the thermal efficiency and exergy efficiency of R125 in transcritical cycle is 46.4% and 20% lower than that of R123 in subcritical ORC, it provides 20.7% larger recovery efficiency. And the LEC value is relatively low. Moreover, 22032L petroleum is saved and 74,019 kg CO 2 is reduced per year when the LEC value is used as
International Nuclear Information System (INIS)
Sarvi, Mohammad; Avanaki, Isa Nasiri
2015-01-01
Highlights: • A new method to improve the performance of renewable power management is proposed. • The proposed method is based on Fuzzy Logic optimized by the Water Cycle Algorithm. • The proposed method characteristics are compared with two other methods. • The comparisons confirm that the proposed method is robust and effectiveness one. - Abstract: This paper aims to improve the power management system of a Stand-alone Hybrid Green Power generation based on the Fuzzy Logic Controller optimized by the Water Cycle Algorithm. The proposed Stand-alone Hybrid Green Power consists of wind energy conversion and photovoltaic systems as primary power sources and a battery, fuel cell, and Electrolyzer as energy storage systems. Hydrogen is produced from surplus power generated by the wind energy conversion and photovoltaic systems of Stand-alone Hybrid Green Power and stored in the hydrogen storage tank for fuel cell later using when the power generated by primary sources is lower than load demand. The proposed optimized Fuzzy Logic Controller based power management system determines the power that is generated by fuel cell or use by Electrolyzer. In a hybrid system, operation and maintenance cost and reliability of the system are the important issues that should be considered in studies. In this regard, Water Cycle Algorithm is used to optimize membership functions in order to simultaneously minimize the Loss of Power Supply Probability and operation and maintenance. The results are compared with the particle swarm optimization and the un-optimized Fuzzy Logic Controller power management system to prove that the proposed method is robust and effective. Reduction in Loss of Power Supply Probability and operation and maintenance, are the most advantages of the proposed method. Moreover the level of the State of Charge of the battery in the proposed method is higher than other mentioned methods which leads to increase battery lifetime.
Energy Technology Data Exchange (ETDEWEB)
Kurnik, Charles W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Simons, George [Itron, Davis, CA (United States); Barsun, Stephan [Itron, Davis, CA (United States)
2017-11-06
The main focus of most evaluations is to determine the energy-savings impacts of the installed measure. This protocol defines a combined heat and power (CHP) measure as a system that sequentially generates both electrical energy and useful thermal energy from one fuel source at a host customer's facility or residence. This protocol is aimed primarily at regulators and administrators of ratepayer-funded CHP programs; however, project developers may find the protocol useful to understand how CHP projects are evaluated.
An Optimization Framework for Load and Power Distribution in Wind Farms
DEFF Research Database (Denmark)
Soleimanzadeh, Maryam; Wisniewski, Rafal; Kanev, Stoyan
2012-01-01
The aim of this paper is to develop a controller for wind farms to optimize the load and power distribution. In this regard, the farm controller calculates the power reference signals for individual wind turbine controllers such that the sum of the power references tracks the power demanded...... by a system operator. Moreover, the reference signals are determined to reduce the load acting on wind turbines at low frequencies. Therefore, a trade-off is made for load and power control, which is formulated as an optimization problem. Afterwards, the optimization problem for the wind farm modeled...
DEFF Research Database (Denmark)
Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte
2011-01-01
represent the future of electricity markets in some ways, is chosen as the studied power system in this paper. The impact of the optimal operation strategy for electric vehicles together with the optimal load response to spot market price on the distribution power system with high wind power penetrations...... are also discussed in the paper. Simulation results show that the proposed optimal operation strategy is an effective measure to achieve minimum energy costs of the PEV. The optimal operation strategy of the PEV and the optimal load response may have significant effects on the distribution power system......Since the hourly spot market price is available one day ahead in Denmark, the electricity price could be transferred to the consumers and they may make some optimal charge and discharge schedules for their electric vehicles in order to minimize their energy costs. This paper presents an optimal...
International Nuclear Information System (INIS)
Vergne, Frederique; Kerhoas, Mailys; Lety, Benoit; Lutzky, Ana
2015-06-01
The lack of funding is often considered, especially by public decision-makers, as one of the major reasons for the slow-down of implementation of energy transition. However, savings and cash flow have never been so abundant. With exclusive money creation, facilitated by very accommodating monetary policies implemented by central banks, financial markets are over-flown with cash flow. This paradox underlines that the issue is not caused by the lack of financial means but rather on the lack of tools favouring the allocation of such means to energy transition. Investments needs are considerable, ranging from 60 to 70 billion Euros each year, which represents approximately 3% of the European GDP. On the European level, expenses supposed to be dedicated to energy transition are valued around 350 to 400 billion Euros each year during 10 years, or, once again, around 3% of the European GDP. The issue is mainly to allocate investments differently rather than increasing their global volume. Public authorities are not able to manage such investments directly and on their own. However, while private players from the financial sector haven taken initiatives and commitments, these have so far proven insufficient in comparison with the scope of the challenge. It is true that public authorities have often avoided acting directly on financial players. However, finance is not a neutral tool and its players, being part of the economy, have a specific role to play. Beyond the necessary development of local and public funding mechanisms favouring sustainable development projects? Which were not dealt with by the working group? This memo focuses on essential tools to create an efficient mechanism which supports huge allocation of savings on energy transition. Thus, it stresses out a global and innovative proposal with strong potential consequences, involving the implementation and the generalization of an 'energy transition' label for financial products, in order to enable
Optimization of power rationing order based on fuzzy evaluation model
Zhang, Siyuan; Liu, Li; Xie, Peiyuan; Tang, Jihong; Wang, Canlin
2018-04-01
With the development of production and economic growth, China's electricity load has experienced a significant increase. Over the years, in order to alleviate the contradiction of power shortage, a series of policies and measures to speed up electric power construction have been made in china, which promotes the rapid development of the power industry and the power construction has made great achievements. For China, after large-scale power facilities, power grid long-term power shortage situation has been improved to some extent, but in a certain period of time, the power development still exists uneven development. On the whole, it is still in the state of insufficient power, and the situation of power restriction is still severe in some areas, so it is necessary to study on the power rationing.
Stochastic Optimal Wind Power Bidding Strategy in Short-Term Electricity Market
DEFF Research Database (Denmark)
Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte
2012-01-01
Due to the fluctuating nature and non-perfect forecast of the wind power, the wind power owners are penalized for the imbalance costs of the regulation, when they trade wind power in the short-term liberalized electricity market. Therefore, in this paper a formulation of an imbalance cost...... minimization problem for trading wind power in the short-term electricity market is described, to help the wind power owners optimize their bidding strategy. Stochastic optimization and a Monte Carlo method are adopted to find the optimal bidding strategy for trading wind power in the short-term electricity...... market in order to deal with the uncertainty of the regulation price, the activated regulation of the power system and the forecasted wind power generation. The Danish short-term electricity market and a wind farm in western Denmark are chosen as study cases due to the high wind power penetration here...
Directory of Open Access Journals (Sweden)
Li Ran
2017-01-01
Full Text Available Optimal allocation of generalized power sources in distribution network is researched. A simple index of voltage stability is put forward. Considering the investment and operation benefit, the stability of voltage and the pollution emissions of generalized power sources in distribution network, a multi-objective optimization planning model is established. A multi-objective particle swarm optimization algorithm is proposed to solve the optimal model. In order to improve the global search ability, the strategies of fast non-dominated sorting, elitism and crowding distance are adopted in this algorithm. Finally, tested the model and algorithm by IEEE-33 node system to find the best configuration of GP, the computed result shows that with the generalized power reasonable access to the active distribution network, the investment benefit and the voltage stability of the system is improved, and the proposed algorithm has better global search capability.
Optimizing design of converters using power cycling lifetime models
DEFF Research Database (Denmark)
Nielsen, Rasmus Ørndrup; Munk-Nielsen, Stig
2015-01-01
Converter power cycling lifetime depends heavily on converter operation point. A lifetime model of a single power module switched mode power supply with wide input voltage range is shown. A lifetime model is created using a power loss model, a thermal model and a model for power cycling capability...... with a given mission profile. A method to improve the expected lifetime of the converter is presented, taking into account switching frequency, input voltage and transformer turns ratio....
Optimized Swinging Door Algorithm for Wind Power Ramp Event Detection: Preprint
Energy Technology Data Exchange (ETDEWEB)
Cui, Mingjian; Zhang, Jie; Florita, Anthony R.; Hodge, Bri-Mathias; Ke, Deping; Sun, Yuanzhang
2015-08-06
Significant wind power ramp events (WPREs) are those that influence the integration of wind power, and they are a concern to the continued reliable operation of the power grid. As wind power penetration has increased in recent years, so has the importance of wind power ramps. In this paper, an optimized swinging door algorithm (SDA) is developed to improve ramp detection performance. Wind power time series data are segmented by the original SDA, and then all significant ramps are detected and merged through a dynamic programming algorithm. An application of the optimized SDA is provided to ascertain the optimal parameter of the original SDA. Measured wind power data from the Electric Reliability Council of Texas (ERCOT) are used to evaluate the proposed optimized SDA.
Energy Technology Data Exchange (ETDEWEB)
Dall' Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.
2015-07-01
This paper considers a collection of networked nonlinear dynamical systems, and addresses the synthesis of feedback controllers that seek optimal operating points corresponding to the solution of pertinent network-wide optimization problems. Particular emphasis is placed on the solution of semidefinite programs (SDPs). The design of the feedback controller is grounded on a dual e-subgradient approach, with the dual iterates utilized to dynamically update the dynamical-system reference signals. Global convergence is guaranteed for diminishing stepsize rules, even when the reference inputs are updated at a faster rate than the dynamical-system settling time. The application of the proposed framework to the control of power-electronic inverters in AC distribution systems is discussed. The objective is to bridge the time-scale separation between real-time inverter control and network-wide optimization. Optimization objectives assume the form of SDP relaxations of prototypical AC optimal power flow problems.
Directory of Open Access Journals (Sweden)
Ahmed M. Ali
2018-02-01
Full Text Available In light of increasing alerts about limited energy sources and environment degradation, it has become essential to search for alternatives to thermal engine-based vehicles which are a major source of air pollution and fossil fuel depletion. Hybrid electric vehicles (HEVs, encompassing multiple energy sources, are a short-term solution that meets the performance requirements and contributes to fuel saving and emission reduction aims. Power management methods such as regulating efficient energy flow to the vehicle propulsion, are core technologies of HEVs. Intelligent power management methods, capable of acquiring optimal power handling, accommodating system inaccuracies, and suiting real-time applications can significantly improve the powertrain efficiency at different operating conditions. Rule-based methods are simply structured and easily implementable in real-time; however, a limited optimality in power handling decisions can be achieved. Optimization-based methods are more capable of achieving this optimality at the price of augmented computational load. In the last few years, these optimization-based methods have been under development to suit real-time application using more predictive, recognitive, and artificial intelligence tools. This paper presents a review-based discussion about these new trends in real-time optimal power management methods. More focus is given to the adaptation tools used to boost methods optimality in real-time. The contribution of this work can be identified in two points: First, to provide researchers and scholars with an overview of different power management methods. Second, to point out the state-of-the-art trends in real-time optimal methods and to highlight promising approaches for future development.
A Three-Stage Optimal Approach for Power System Economic Dispatch Considering Microgrids
Directory of Open Access Journals (Sweden)
Wei-Tzer Huang
2016-11-01
Full Text Available The inclusion of microgrids (MGs in power systems, especially distribution-substation-level MGs, significantly affects power systems because of the large volumes of import and export power flows. Consequently, power dispatch has become complicated, and finding an optimal solution is difficult. In this study, a three-stage optimal power dispatch model is proposed to solve such dispatch problems. In the proposed model, the entire power system is divided into two parts, namely, the main power grid and MGs. The optimal power dispatch problem is resolved on the basis of multi-area concepts. In stage I, the main power system economic dispatch (ED problem is solved by sensitive factors. In stage II, the optimal power dispatches of the local MGs are addressed via an improved direct search method. In stage III, the incremental linear models for the entire power system can be established on the basis of the solutions of the previous two stages and can be subjected to linear programming to determine the optimal reschedules from the original dispatch solutions. The proposed method is coded using Matlab and tested by utilizing an IEEE 14-bus test system to verify its feasibility and accuracy. Results demonstrated that the proposed approach can be used for the ED of power systems with MGs as virtual power plants.
Keulen, T. van; Mullem, D. van; Jager, B. van; Kessels, J.T.B.A.; Steinbuch, M.
2012-01-01
Hybrid electric vehicles require an algorithm that controls the power split between the internal combustion engine and electric machine(s), and the opening and closing of the clutch. Optimal control theory is applied to derive a methodology for a real-time optimal-control-based power split
Modeling and optimization of geothermal power plants using the binary fluid cycle
Energy Technology Data Exchange (ETDEWEB)
Walter, R.A.
1976-09-01
A computer simulation of a binary fluid cycle power plant for use with geothermal energy sources, and the subsequent optimization of this power plant type over a range of geothermal source conditions are described. The optimization technique employed for this analysis was based upon the principle of maximum use of geothermal energy.
Optimization Tool for Direct Water Cooling System of High Power IGBT Modules
DEFF Research Database (Denmark)
Bahman, Amir Sajjad; Blaabjerg, Frede
2016-01-01
important issue for thermal design engineers. This paper aims to present a user friendly optimization tool for direct water cooling system of a high power module which enables the cooling system designer to identify the optimized solution depending on customer load profiles and available pump power. CFD...
Optimization for Customized Power Quality Service in Multibus Microgrids
DEFF Research Database (Denmark)
Meng, Lexuan; Guerrero, Josep M.
2017-01-01
Power quality requirements for different consumers and electric equipment are distinctive. Conventionally, common power quality standards are applied to the whole power grid inducing debate between technical commissions. Customized power quality standards for different consumers become a widely...... accepted solution. The main challenge is on the proper regulation of power quality in different areas. This paper considers a multibus microgrid system, where the power quality in each area has individual adjustable standard. Voltage unbalance, induced by connection of single-phase loads, is taken...
Multi-objective PSO based optimal placement of solar power DG in radial distribution system
Directory of Open Access Journals (Sweden)
Mahesh Kumar
2017-06-01
Full Text Available Ever increasing trend of electricity demand, fossil fuel depletion and environmental issues request the integration of renewable energy into the distribution system. The optimal planning of renewable distributed generation (DG is much essential for ensuring maximum benefits. Hence, this paper proposes the optimal placement of probabilistic based solar power DG into the distribution system. The two objective functions such as power loss reduction and voltage stability index improvement are optimized. The power balance and voltage limits are kept as constraints of the problem. The non-sorting pare to-front based multi-objective particle swarm optimization (MOPSO technique is proposed on standard IEEE 33 radial distribution test system.
Optimal Power Flow Modelling and Analysis of Hybrid AC-DC Grids with Offshore Wind Power Plant
DEFF Research Database (Denmark)
Dhua, Debasish; Huang, Shaojun; Wu, Qiuwei
2017-01-01
In order to develop renewables based energy systems, the installation of the offshore wind power plants (WPPs) is globally encouraged. However, wind power generation is intermittent and uncertain. An accurate modelling and evaluation reduces investment and provide better operation. Hence......, the wind power production level also plays a major role in a hybrid system on transmission loss evaluation. The developed model is tested in Low, Medium and High wind power production levels to determine the objective function of the OPF solution. MATLAB Optimization Toolbox and MATLAB script are used......, it is essential to develop a suitable model and apply optimization algorithms for different application scenarios. The objective of this work is to develop a generalized model and evaluate the Optimal Power Flow (OPF) solutions in a hybrid AC/DC system including HVDC (LCC based) and offshore WPP (VSC based...
Wang, Wu; Huang, Wei; Zhang, Yongjun
2018-03-01
The grid-integration of Photovoltaic-Storage System brings some undefined factors to the network. In order to make full use of the adjusting ability of Photovoltaic-Storage System (PSS), this paper puts forward a reactive power optimization model, which are used to construct the objective function based on power loss and the device adjusting cost, including energy storage adjusting cost. By using Cataclysmic Genetic Algorithm to solve this optimization problem, and comparing with other optimization method, the result proved that: the method of dynamic extended reactive power optimization this article puts forward, can enhance the effect of reactive power optimization, including reducing power loss and device adjusting cost, meanwhile, it gives consideration to the safety of voltage.
optimal selection of hydraulic turbines for small hydro electric power
African Journals Online (AJOL)
eobe
Keywords: optimal selection, SHP turbine, flow duration curve, energy efficiency, annual capacity factor. 1. INTRODUCTION ... depleted, with adverse environmental impacts downstream ..... Technologies, Financing Cogeneration and Small -.
Energy Technology Data Exchange (ETDEWEB)
Storm Soerensen, M.; Madsen, P.K. [NESA A/S, Research and Development Dept. (Denmark)
1997-12-01
In recent years many campaigns and projects have been carried out with the purpose of reducing the energy consumption. Simultaneously a lot of economic and structural changes are taking place in society in general; changes which also affect the size of the electricity consumption. Furthermore, there is a trend towards increased use of wind mills and decentral combined heating and power plants, which affects the electricity load of the local area. It is difficult to identify and separate the effect of each of these attitude-adjusting activities. The project `Development of methods for evaluation of the effect of electricity saving and load levelling measures` focuses on two different methods which, on different levels, can be used to determine the impact of different different activities on the electricity consumption. Both methods are based on mathematical statistics, and they consist of an analysis of historical data and a test campaign which will make it possible to test specific activities in a comparatively small scale. The historical part covers the years 1974 to 1994 and include such variables as: demography, economic factors, climatic conditions, periods of electricity saving campaigns, the start of billing according to time of day tariff etc. The wish to be able to measure the extent of these energy saving and load reducing initiatives resulted in a test campaign which was carried out under very restricted conditions starting in the fall of 1996. If the effect of the test campaign can be measured and as a consequence of this a method can be estimated, it will be possible to place models which can measure the effect of future campaigns. The primary object of the campaign is not the size of the electricity savings of the individual customer, but rather to obtain total savings for the entire group of customers. The test has been structured in a way which makes it possible to perform an analysis of the effect of the campaign by use of analysis of intervention
User's manual for the BNW-II optimization code for dry/wet-cooled power plants
International Nuclear Information System (INIS)
Braun, D.J.; Bamberger, J.A.; Braun, D.J.; Faletti, D.W.; Wiles, L.E.
1978-05-01
The User's Manual describes how to operate BNW-II, a computer code developed by the Pacific Northwest Laboratory (PNL) as a part of its activities under the Department of Energy (DOE) Dry Cooling Enhancement Program. The computer program offers a comprehensive method of evaluating the cost savings potential of dry/wet-cooled heat rejection systems. Going beyond simple ''figure-of-merit'' cooling tower optimization, this method includes such items as the cost of annual replacement capacity, and the optimum split between plant scale-up and replacement capacity, as well as the purchase and operating costs of all major heat rejection components. Hence the BNW-II code is a useful tool for determining potential cost savings of new dry/wet surfaces, new piping, or other components as part of an optimized system for a dry/wet-cooled plant
Optimization of extinguishing agents for nuclear power plants
International Nuclear Information System (INIS)
Boleman, M.; Lipar, M.; Balog, K.
1998-01-01
Focus is placed on use of extinguishing agents in nuclear power plants. The advantages and disadvantages of these agents are compared. Further perspectives for using particular extinguishing agents in nuclear power plants are outlined. (author)
Optimal power allocation for SM-OFDM systems with imperfect channel estimation
International Nuclear Information System (INIS)
Yu, Feng; Song, Lijun; Lei, Xia; Xiao, Yue; Jiang, Zhao Xiang; Jin, Maozhu
2016-01-01
This paper analyses the bit error rate (BER) of the spatial modulation orthogonal frequency division multiplex (SM-OFDM) system and derives the optimal power allocation between the data and the pilot symbols by minimizing the upper bound for the BER operating with imperfect channel estimation. Furthermore, we prove the proposed optimal power allocation scheme applies to all generalized linear interpolation techniques with the minimum mean square error (MMSE) channel estimation . Simulation results show that employing the proposed optimal power allocation provides a substantial gain in terms of the average BER performance for the SM-OFDM system compared to its equal-power-allocation counterpart.
Channel Estimation and Optimal Power Allocation for a Multiple-Antenna OFDM System
Directory of Open Access Journals (Sweden)
Yao Kung
2002-01-01
Full Text Available We propose combining channel estimation and optimal power allocation approaches for a multiple-antenna orthogonal frequency division multiplexing (OFDM system in high-speed transmission applications. We develop a least-square channel estimation approach, derive the performance bound of the estimator, and investigate the optimal training sequences for initial channel acquisition. Based on the channel estimates, the optimal power allocation solution which maximizes the bandwidth efficiency is derived under power and quality of service (Qos (symbol error rate constraints. It is shown that combining channel tracking and adaptive power allocation can dramatically enhance the outage capacity of an OFDM multiple-antenna system when severing fading occurs.
A problem of optimization for the specific cost of installed electric power in nuclear plants
Energy Technology Data Exchange (ETDEWEB)
Sultan, M A; Khattab, M S [Reactors Dept. nuclear research centre, atomic energy authority, Cairo, (Egypt)
1995-10-01
The optimization problem analyzed in this paper is related to the thermal cycle parameters in nuclear power stations having steam generators. The optimization the specific cost of installed power with respect to the average operating saturation temperature in the station thermal cycle. The analysis considers the maximum fuel cladding temperature as a limiting factor in the optimization process as it is related to the safe operation of the reactor. 4 figs.
Directory of Open Access Journals (Sweden)
Heba Ahmed Hassan
2017-01-01
Full Text Available This paper applies a relatively new optimization method, the Grey Wolf Optimizer (GWO algorithm for Optimal Power Flow (OPF of two-terminal High Voltage Direct Current (HVDC electrical power system. The OPF problem of pure AC power systems considers the minimization of total costs under equality and inequality constraints. Hence, the OPF problem of integrated AC-DC power systems is extended to incorporate HVDC links, while taking into consideration the power transfer control characteristics using a GWO algorithm. This algorithm is inspired by the hunting behavior and social leadership of grey wolves in nature. The proposed algorithm is applied to two different case-studies: the modified 5-bus and WSCC 9-bus test systems. The validity of the proposed algorithm is demonstrated by comparing the obtained results with those reported in literature using other optimization techniques. Analysis of the obtained results show that the proposed GWO algorithm is able to achieve shorter CPU time, as well as minimized total cost when compared with already existing optimization techniques. This conclusion proves the efficiency of the GWO algorithm.
Energy Technology Data Exchange (ETDEWEB)
Tippachon, Wiwat; Rerkpreedapong, Dulpichet [Department of Electrical Engineering, Kasetsart University, 50 Phaholyothin Rd., Ladyao, Jatujak, Bangkok 10900 (Thailand)
2009-07-15
This paper presents a multiobjective optimization methodology to optimally place switches and protective devices in electric power distribution networks. Identifying the type and location of them is a combinatorial optimization problem described by a nonlinear and nondifferential function. The multiobjective ant colony optimization (MACO) has been applied to this problem to minimize the total cost while simultaneously minimize two distribution network reliability indices including system average interruption frequency index (SAIFI) and system interruption duration index (SAIDI). Actual distribution feeders are used in the tests, and test results have shown that the algorithm can determine the set of optimal nondominated solutions. It allows the utility to obtain the optimal type and location of devices to achieve the best system reliability with the lowest cost. (author)
Directory of Open Access Journals (Sweden)
Yi Tang
2017-05-01
Full Text Available In a competitive electricity market with substantial involvement of renewable electricity, maximizing profits by optimizing bidding strategies is crucial to different power producers including conventional power plants and renewable ones. This paper proposes a game-theoretic bidding optimization method based on bi-level programming, where power producers are at the upper level and utility companies are at the lower level. The competition among the multiple power producers is formulated as a non-cooperative game in which bidding curves are their strategies, while uniform clearing pricing is considered for utility companies represented by an independent system operator. Consequently, based on the formulated game model, the bidding strategies for power producers are optimized for the day-ahead market and the intraday market with considering the properties of renewable energy; and the clearing pricing for the utility companies, with respect to the power quantity from different power producers, is optimized simultaneously. Furthermore, a distributed algorithm is provided to search the solution of the generalized Nash equilibrium. Finally, simulation results were performed and discussed to verify the feasibility and effectiveness of the proposed non-cooperative game-based bi-level optimization approach.
Offshore Wind Farm Layout Design Considering Optimized Power Dispatch Strategy
DEFF Research Database (Denmark)
Hou, Peng; Hu, Weihao; N. Soltani, Mohsen
2017-01-01
Offshore wind farm has drawn more and more attention recently due to its higher energy capacity and more freedom to occupy area. However, the investment is higher. In order to make a cost-effective wind farm, the wind farm layout should be optimized. The wake effect is one of the dominant factors...... leading to energy losses. It is expected that the optimized placement of wind turbines (WT) over a large sea area can lead to the best tradeoff between energy yields and capital investment. This paper proposes a novel way to position offshore WTs for a regular shaped wind farm. In addition to optimizing...... the direction of wind farm placement and the spacing between WTs, the control strategy’s impact on energy yields is also discussed. Since the problem is non-convex and lots of optimization variables are involved, an evolutionary algorithm, the particle swarm optimization algorithm (PSO), is adopted to find...
Short-Term Wind Power Forecasting Using the Enhanced Particle Swarm Optimization Based Hybrid Method
Wen-Yeau Chang
2013-01-01
High penetration of wind power in the electricity system provides many challenges to power system operators, mainly due to the unpredictability and variability of wind power generation. Although wind energy may not be dispatched, an accurate forecasting method of wind speed and power generation can help power system operators reduce the risk of an unreliable electricity supply. This paper proposes an enhanced particle swarm optimization (EPSO) based hybrid forecasting method for short-term wi...
International Nuclear Information System (INIS)
Chen, Gonggui; Liu, Lilan; Song, Peizhu; Du, Yangwei
2014-01-01
Highlights: • New method for MOORPD problem using MOCIPSO and MOIPSO approaches. • Constrain-prior Pareto-dominance method is proposed to meet the constraints. • The limits of the apparent power flow of transmission line are considered. • MOORPD model is built up for MOORPD problem. • The achieved results by MOCIPSO and MOIPSO approaches are better than MOPSO method. - Abstract: Multi-objective optimal reactive power dispatch (MOORPD) seeks to not only minimize power losses, but also improve the stability of power system simultaneously. In this paper, the static voltage stability enhancement is achieved through incorporating L index in MOORPD problem. Chaotic improved PSO-based multi-objective optimization (MOCIPSO) and improved PSO-based multi-objective optimization (MOIPSO) approaches are proposed for solving complex multi-objective, mixed integer nonlinear problems such as minimization of power losses and L index in power systems simultaneously. In MOCIPSO and MOIPSO based optimization approaches, crossover operator is proposed to enhance PSO diversity and improve their global searching capability, and for MOCIPSO based optimization approach, chaotic sequences based on logistic map instead of random sequences is introduced to PSO for enhancing exploitation capability. In the two approaches, constrain-prior Pareto-dominance method (CPM) is proposed to meet the inequality constraints on state variables, the sorting and crowding distance methods are considered to maintain a well distributed Pareto optimal solutions, and moreover, fuzzy set theory is employed to extract the best compromise solution over the Pareto optimal curve. The proposed approaches have been examined and tested in the IEEE 30 bus and the IEEE 57 bus power systems. The performances of MOCIPSO, MOIPSO, and multi-objective PSO (MOPSO) approaches are compared with respect to multi-objective performance measures. The simulation results are promising and confirm the ability of MOCIPSO and
Energy Technology Data Exchange (ETDEWEB)
Andriushchenko, A.I.
1981-01-01
The problems of increasing the efficiency and optimizing the operational conditions of a thermoelectric power plant and providing efficient operational conditions of the primary and auxillary equipment at a thermoelectric power plant are examined. Methodologies and designs for optimizing the primary parameters of the power-generating equipment based on economic factors are given. A number of recommendations for designing equipment based on the research results are given.
Directory of Open Access Journals (Sweden)
Mohamed Zellagui
2017-09-01
Full Text Available The paper presents a new hybrid global optimization algorithm based on Chemical Reaction based Optimization (CRO and Di¤erential evolution (DE algorithm for nonlinear constrained optimization problems. This approach proposed for the optimal coordination and setting relays of directional overcurrent relays in complex power systems. In protection coordination problem, the objective function to be minimized is the sum of the operating time of all main relays. The optimization problem is subject to a number of constraints which are mainly focused on the operation of the backup relay, which should operate if a primary relay fails to respond to the fault near to it, Time Dial Setting (TDS, Plug Setting (PS and the minimum operating time of a relay. The hybrid global proposed optimization algorithm aims to minimize the total operating time of each protection relay. Two systems are used as case study to check the effeciency of the optimization algorithm which are IEEE 4-bus and IEEE 6-bus models. Results are obtained and presented for CRO and DE and hybrid CRO-DE algorithms. The obtained results for the studied cases are compared with those results obtained when using other optimization algorithms which are Teaching Learning-Based Optimization (TLBO, Chaotic Differential Evolution Algorithm (CDEA and Modiffied Differential Evolution Algorithm (MDEA, and Hybrid optimization algorithms (PSO-DE, IA-PSO, and BFOA-PSO. From analysing the obtained results, it has been concluded that hybrid CRO-DO algorithm provides the most optimum solution with the best convergence rate.
Hybrid PV/diesel solar power system design using multi-level factor analysis optimization
Drake, Joshua P.
Solar power systems represent a large area of interest across a spectrum of organizations at a global level. It was determined that a clear understanding of current state of the art software and design methods, as well as optimization methods, could be used to improve the design methodology. Solar power design literature was researched for an in depth understanding of solar power system design methods and algorithms. Multiple software packages for the design and optimization of solar power systems were analyzed for a critical understanding of their design workflow. In addition, several methods of optimization were studied, including brute force, Pareto analysis, Monte Carlo, linear and nonlinear programming, and multi-way factor analysis. Factor analysis was selected as the most efficient optimization method for engineering design as it applied to solar power system design. The solar power design algorithms, software work flow analysis, and factor analysis optimization were combined to develop a solar power system design optimization software package called FireDrake. This software was used for the design of multiple solar power systems in conjunction with an energy audit case study performed in seven Tibetan refugee camps located in Mainpat, India. A report of solar system designs for the camps, as well as a proposed schedule for future installations was generated. It was determined that there were several improvements that could be made to the state of the art in modern solar power system design, though the complexity of current applications is significant.
Le Nir, Vincent; Moonen, Marc; Verlinden, Jan; Guenach, Mamoun
2009-02-01
Recently, the duality between Multiple Input Multiple Output (MIMO) Multiple Access Channels (MAC) and MIMO Broadcast Channels (BC) has been established under a total power constraint. The same set of rates for MAC can be achieved in BC exploiting the MAC-BC duality formulas while preserving the total power constraint. In this paper, we describe the BC optimal power allo- cation applying this duality in a downstream x-Digital Subscriber Lines (xDSL) context under a total power constraint for all modems over all tones. Then, a new algorithm called BC-Optimal Spectrum Balancing (BC-OSB) is devised for a more realistic power allocation under per-modem total power constraints. The capacity region of the primal BC problem under per-modem total power constraints is found by the dual optimization problem for the BC under per-modem total power constraints which can be rewritten as a dual optimization problem in the MAC by means of a precoder matrix based on the Lagrange multipliers. We show that the duality gap between the two problems is zero. The multi-user power allocation problem has been solved for interference channels and MAC using the OSB algorithm. In this paper we solve the problem of multi-user power allocation for the BC case using the OSB algorithm as well and we derive a computational efficient algorithm that will be referred to as BC-OSB. Simulation results are provided for two VDSL2 scenarios: the first one with Differential-Mode (DM) transmission only and the second one with both DM and Phantom- Mode (PM) transmissions.
Dynamic Optimal Energy Flow in the Integrated Natural Gas and Electrical Power Systems
DEFF Research Database (Denmark)
Fang, Jiakun; Zeng, Qing; Ai, Xiaomeng
2018-01-01
. Simulation on the test case illustrates the success of the modelling and the beneficial roles of the power-to-gas are analyzed. The proposed model can be used in the decision support for both planning and operation of the coordinated natural gas and electrical power systems.......This work focuses on the optimal operation of the integrated gas and electrical power system with bi-directional energy conversion. Considering the different response times of the gas and power systems, the transient gas flow and steady- state power flow are combined to formulate the dynamic...... optimal energy flow in the integrated gas and power systems. With proper assumptions and simplifications, the problem is transformed into a single stage linear programming. And only a single stage linear programming is needed to obtain the optimal operation strategy for both gas and power systems...
Optimization of Wind-Marine Hybrid Power System Configuration Based on Genetic Algorithm
Institute of Scientific and Technical Information of China (English)
SHI Hongda; LI Linna; ZHAO Chenyu
2017-01-01
Multi-energy power systems can use energy generated from various sources to improve power generation reliability.This paper presents a cost-power generation model of a wind-tide-wave energy hybrid power system for use on a remote island,where the configuration is optimized using a genetic algorithm.A mixed integer programming model is used and a novel object function,including cost and power generation,is proposed to solve the boundary problem caused by existence of two goals.Using this model,the final optimized result is found to have a good fit with local resources.
BEST-4, Fuel Cycle and Cost Optimization for Discrete Power Levels
International Nuclear Information System (INIS)
1973-01-01
1 - Nature of physical problem solved: Determination of optimal power strategy for a fuel cycle, for discrete power levels and n temporal stages, taking into account replacement energy costs and de-rating. 2 - Method of solution: Dynamic programming. 3 - Restrictions on the complexity of the problem: Restrictions may arise from number of power levels and temporal stages, due to machine limitations
Mission-profile based multi-objective optimization of power electronics converter for wind turbines
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh; Teodorescu, Remus; Kerekes, Tamas
2017-01-01
-objective optimization approach for designing power converter is presented. The objective is to minimize the energy loss for a given load profile as against the conventional approach of minimizing power loss at specific loading conditions. The proposed approach is illustrated by designing a grid-side power converter...
Optimization of the cooling power distribution in a superconducting linac
International Nuclear Information System (INIS)
Wendl, C.M.; Noe, J.W.
1996-01-01
The benefits of setting the resonators in a superconducting heavy-ion linac to a certain optimum distribution of cooling power have been evaluated in terms of the total acceleration such a distribution may produce, compared to a distribution in which each resonator dissipates power equally. The optimum power distribution can be expressed in closed form in certain simplified cases, but the general case is solved by equalizing the 'marginal power cost' of the resonators by iteration in a computer simulation. For the Stony Brook linac an additional possible acceleration of several percent is thus predicted for typical beams. (author)
Genetic Spot Optimization for Peak Power Estimation in Large VLSI Circuits
Directory of Open Access Journals (Sweden)
Michael S. Hsiao
2002-01-01
Full Text Available Estimating peak power involves optimization of the circuit's switching function. The switching of a given gate is not only dependent on the output capacitance of the node, but also heavily dependent on the gate delays in the circuit, since multiple switching events can result from uneven circuit delay paths in the circuit. Genetic spot expansion and optimization are proposed in this paper to estimate tight peak power bounds for large sequential circuits. The optimization spot shifts and expands dynamically based on the maximum power potential (MPP of the nodes under optimization. Four genetic spot optimization heuristics are studied for sequential circuits. Experimental results showed an average of 70.7% tighter peak power bounds for large sequential benchmark circuits was achieved in short execution times.
Optimal Energy-Efficient Sensing and Power Allocation in Cognitive Radio Networks
Directory of Open Access Journals (Sweden)
Xia Wu
2014-01-01
Full Text Available We consider a joint optimization of sensing parameter and power allocation for an energy-efficient cognitive radio network (CRN in which the primary user (PU is protected. The optimization problem to maximize the energy efficiency of CRN is formulated as a function of two variables, which are sensing time and transmit power, subject to the average interference power to the PU and the target detection probability. During the optimizing process, the quality of service parameter (the minimum rate acceptable to secondary users (SUs has also been taken into consideration. The optimal solutions are analyzed and an algorithm combined with fractional programming that maximizes the energy efficiency for CRN is presented. Numerical results show that the performance improvement is achieved by the joint optimization of sensing time and power allocation.
Optimal power flow for technically feasible Energy Management systems in Islanded Microgrids
DEFF Research Database (Denmark)
Sanseverino, Eleonora Riva; T. T. Quynh, T.; Di Silvestre, Maria Luisa
2016-01-01
This paper presents a combined optimal energy and power flow management for islanded microgrids. The highest control level in this case will provide a feasible and optimized operating point around the economic optimum. In order to account for both unbalanced and balanced loads, the optimal power...... flow is carried out using a Glow-worm Swarm Optimizer. The control level is organized into two different sub-levels, the highest of which accounts for minimum cost operation and the lowest one solving the optimal power flow and devising the set points of inverter interfaced generation units...... and rotating machines with a minimum power loss. A test has been carried out for 6 bus islanded microgrids to show the efficiency and feasibility of the proposed technique....
International Nuclear Information System (INIS)
Sechilariu, Manuela; Wang, Bao Chao; Locment, Fabrice; Jouglet, Antoine
2014-01-01
Highlights: • DC microgrid (PV array, storage, power grid connection, DC load) with multi-layer supervision control. • Power balancing following power flow optimization while providing interface for smart grid communication. • Optimization under constraints: storage capability, grid power limitations, grid time-of-use pricing. • Experimental validation of DC microgrid power flow optimization by multi-layer supervision control. • DC microgrid able to perform peak shaving, to avoid undesired injection, and to make full use of locally energy. - Abstract: Urban areas have great potential for photovoltaic (PV) generation, however, direct PV power injection has limitations for high level PV penetration. It induces additional regulations in grid power balancing because of lacking abilities of responding to grid issues such as reducing grid peak consumption or avoiding undesired injections. The smart grid implementation, which is designed to meet these requirements, is facilitated by microgrids development. This paper presents a DC microgrid (PV array, storage, power grid connection, DC load) with multi-layer supervision control which handles instantaneous power balancing following the power flow optimization while providing interface for smart grid communication. The optimization takes into account forecast of PV power production and load power demand, while satisfying constraints such as storage capability, grid power limitations, grid time-of-use pricing and grid peak hour. Optimization, whose efficiency is related to the prediction accuracy, is carried out by mixed integer linear programming. Experimental results show that the proposed microgrid structure is able to control the power flow at near optimum cost and ensures self-correcting capability. It can respond to issues of performing peak shaving, avoiding undesired injection, and making full use of locally produced energy with respect to rigid element constraints
Directory of Open Access Journals (Sweden)
Chun-An Cheng
2017-01-01
Full Text Available This paper presents a single-stage alternating current (AC/direct current (DC light-emitting diode (LED tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series resonant converter cascaded with a bridge rectifier into a single-stage power-conversion topology. The features of the presented driver are high efficiency (>91%, satisfying power factor (PF > 0.96, low input-current total-harmonic distortion (THD < 10%, low output voltage ripple factor (<7.5%, low output current ripple factor (<8%, and zero-voltage switching (ZVS obtained on both power switches. Operational principles are described in detail, and experimental results obtained from an 18 W-rated LED tube lamp for T8/T10 fluorescent lamp replacements with input utility-line voltages ranging from 100 V to 120 V have demonstrated the functionality of the presented driver suitable for indoor lighting applications.
Multi-Objective Optimization Control for the Aerospace Dual-Active Bridge Power Converter
Directory of Open Access Journals (Sweden)
Tao Lei
2018-05-01
Full Text Available With the development of More Electrical Aircraft (MEA, the electrification of secondary power systems in aircraft is becoming more and more common. As the key power conversion device, the dual active bridge (DAB converter is the power interface for the energy storage system with the high voltage direct current (HVDC bus in aircraft electrical power systems. In this paper, a DAB DC-DC converter is designed to meet aviation requirements. The extended dual phase shifted control strategy is adopted, and a multi-objective genetic algorithm is applied to optimize its operating performance. Considering the three indicators of inductance current root mean square root (RMS value, negative reverse power and direct current (DC bias component of the current for the high frequency transformer as the optimization objectives, the DAB converter’s optimization model is derived to achieve soft switching as the main constraint condition. Optimized methods of controlling quantity for the DAB based on the evolution and genetic algorithm is used to solve the model, and a number of optimal control parameters are obtained under different load conditions. The results of digital, hard-in-loop simulation and hardware prototype experiments show that the three performance indexes are all suppressed greatly, and the optimization method proposed in this paper is reasonable. The work of this paper provides a theoretical basis and researching method for the multi-objective optimization of the power converter in the aircraft electrical power system.
Use Conditions and Efficiency Measurements of DC Power Optimizers for Photovoltaic Systems: Preprint
Energy Technology Data Exchange (ETDEWEB)
Deline, C.; MacAlpine, S.
2013-10-01
No consensus standard exists for estimating annual conversion efficiency of DC-DC converters or power optimizers in photovoltaic (PV) applications. The performance benefits of PV power electronics including per-panel DC-DC converters depend in large part on the operating conditions of the PV system, along with the performance characteristics of the power optimizer itself. This work presents acase study of three system configurations that take advantage of the capabilities of DC power optimizers. Measured conversion efficiencies of DC-DC converters are applied to these scenarios to determine the annual weighted operating efficiency. A simplified general method of reporting weighted efficiency is given, based on the California Energy Commission's CEC efficiency rating and severalinput / output voltage ratios. Efficiency measurements of commercial power optimizer products are presented using the new performance metric, along with a description of the limitations of the approach.
Energy Technology Data Exchange (ETDEWEB)
Widen, Joakim
2011-01-15
This is the final report from a project in which an early-design-phase tool for photovoltaic (PV) systems has been developed. The aim of the tool is to provide a quick and easy way to estimate the electricity production and the economy of a PV system. Although it is effective and easy to use, the model takes into account all the important factors that affect the design, performance and economy of a system, and makes it possible with more in-depth analyses as well. The intended users of the tool are both electricity end-users thinking on investing in a small-scale system and large investors planning in an early project phase for large-scale PV systems. The developed tool is a simulation tool rather than an optimization tool. However, as the model is efficient and simple to use, it is easy to vary parameters and input data in different scenarios to arrive at an optimal solution. In order for the tool to realistically estimate the load matching of a PV system, which depends on seasonal and diurnal variations in both load and production profiles, the computations are made on an hourly basis. An hourly resolution is the most common one in meteorological data and to increase the resolution further is neither practically possible nor required for accuracy. The hourly irradiation data used in the model were collected from the publicly available STRAaNG database, which is maintained by the Swedish Meteorological and Hydrological Institute (SMHI). Idealized hourly load profiles for typical Swedish end-user categories are also included in the tool. A general computational model was implemented in Matlab, which provided easy testing, visualization and validation of the model. The computations involved can be summarized in four main steps: 1 Radiation computations. This involves a transposition of radiation components to the tilted plane of the PV array. The model takes the orientation of the system into account and uses assumed albedo values of the surroundings to add ground
Energy Technology Data Exchange (ETDEWEB)
Peralta Solorio, Jose Luis [Fideicomiso para el Ahorro de Energia Electrica (Mexico)]. E-mail: jose.peralta@cfe.gob.mx
2006-04-15
In Mexico the second most used electrical appliance is: refrigerator. Owing to its use, it would be a promising option for electric power saving. In Guadalajara, Reynosa and Tampico it was performed a study with the aim of launching a project to replace the old refrigerators with new ones which are more effective and less expensive. Since the refrigerators cost and the electrical invoicing saving, the electric appliance change is profitable. To expect with this replacement more than eight million of refrigerators manufactured before 1997 will be changed. [Spanish] El refrigerador es el segundo electrodomestico mas utilizado a nivel nacional, esto permite que debido a su uso sea una opcion prometedora para el ahorro de energia electrica. Se hizo un estudio en Guadalajara, Reynosa y Tampico con el fin de lanzar un proyecto para sustituir los refrigeradores viejos por unos nuevos que sean mas eficaces y menos costosos. Por el costo de los refrigeradores y el ahorro en la facturacion electrica, el cambio de electrodomestico es rentable, de esta manera se espera que los mas de ocho millones de refrigeradores fabricados antes de 1997 que existen en el pais sean cambiados.
Optimizing the design of very high power, high performance converters
International Nuclear Information System (INIS)
Edwards, R.J.; Tiagha, E.A.; Ganetis, G.; Nawrocky, R.J.
1980-01-01
This paper describes how various technologies are used to achieve the desired performance in a high current magnet power converter system. It is hoped that the discussions of the design approaches taken will be applicable to other power supply systems where stringent requirements in stability, accuracy and reliability must be met
Modeling of Optimal Power Generation using Multiple Kites
Williams, P.; Lansdorp, B.; Ockels, W.J.
2008-01-01
Kite systems have the potential to revolutionize energy generation. Large scale systems are envisioned that can fly autonomously in “power generation” cycles which drive a ground-based generator. In order for such systems to produce power efficiently, good models of the system are required. This
RF power consumption emulation optimized with interval valued homotopies
DEFF Research Database (Denmark)
Musiige, Deogratius; Anton, François; Yatskevich, Vital
2011-01-01
This paper presents a methodology towards the emulation of the electrical power consumption of the RF device during the cellular phone/handset transmission mode using the LTE technology. The emulation methodology takes the physical environmental variables and the logical interface between...... the baseband and the RF system as inputs to compute the emulated power dissipation of the RF device. The emulated power, in between the measured points corresponding to the discrete values of the logical interface parameters is computed as a polynomial interpolation using polynomial basis functions....... The evaluation of polynomial and spline curve fitting models showed a respective divergence (test error) of 8% and 0.02% from the physically measured power consumption. The precisions of the instruments used for the physical measurements have been modeled as intervals. We have been able to model the power...
Energy Technology Data Exchange (ETDEWEB)
Gutierrez Ramirez, Ranulfo; Fernandez Montiel, Manuel Francisco [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)
1999-07-01
Some recent experiences of the Management of Thermal Processes of the Instituto de Investigaciones Electricas (IIE) related to the works on generating power stations of electricity, plants of cogeneration and energy saving are presented. [Spanish] Se presentan algunas experiencias recientes de la Gerencia de Procesos Termicos del Instituto de Investigaciones Electricas (IIE) relacionadas con los trabajos sobre centrales generadoras de electricidad, plantas de cogeneracion y ahorro de energia.
Pilot power optimization for AF relaying using maximum likelihood channel estimation
Wang, Kezhi
2014-09-01
Bit error rates (BERs) for amplify-and-forward (AF) relaying systems with two different pilot-symbol-aided channel estimation methods, disintegrated channel estimation (DCE) and cascaded channel estimation (CCE), are derived in Rayleigh fading channels. Based on these BERs, the pilot powers at the source and at the relay are optimized when their total transmitting powers are fixed. Numerical results show that the optimized system has a better performance than other conventional nonoptimized allocation systems. They also show that the optimal pilot power in variable gain is nearly the same as that in fixed gain for similar system settings. andcopy; 2014 IEEE.
Directory of Open Access Journals (Sweden)
Jun Yang
2015-08-01
Full Text Available The carbon emissions trading market and direct power purchases by large consumers are two promising directions of power system development. To trace the carbon emission flow in the power grid, the theory of carbon emission flow is improved by allocating power loss to the load side. Based on the improved carbon emission flow theory, an optimal dispatch model is proposed to optimize the cost of both large consumers and the power grid, which will benefit from the carbon emissions trading market. Moreover, to better simulate reality, the direct purchase of power by large consumers is also considered in this paper. The OPF (optimal power flow method is applied to solve the problem. To evaluate our proposed optimal dispatch strategy, an IEEE 30-bus system is used to test the performance. The effects of the price of carbon emissions and the price of electricity from normal generators and low-carbon generators with regards to the optimal dispatch are analyzed. The simulation results indicate that the proposed strategy can significantly reduce both the operation cost of the power grid and the power utilization cost of large consumers.
Optimization of GM(1,1) power model
Luo, Dang; Sun, Yu-ling; Song, Bo
2013-10-01
GM (1,1) power model is the expansion of traditional GM (1,1) model and Grey Verhulst model. Compared with the traditional models, GM (1,1) power model has the following advantage: The power exponent in the model which best matches the actual data values can be found by certain technology. So, GM (1,1) power model can reflect nonlinear features of the data, simulate and forecast with high accuracy. It's very important to determine the best power exponent during the modeling process. In this paper, according to the GM(1,1) power model of albino equation is Bernoulli equation, through variable substitution, turning it into the GM(1,1) model of the linear albino equation form, and then through the grey differential equation properly built, established GM(1,1) power model, and parameters with pattern search method solution. Finally, we illustrate the effectiveness of the new methods with the example of simulating and forecasting the promotion rates from senior secondary schools to higher education in China.
Seasonal optimal mix of wind and solar power in a future, highly renewable Europe
Energy Technology Data Exchange (ETDEWEB)
Heide, Dominik [Frankfurt Institute for Advanced Studies (FIAS) and Frankfurt International Graduate School for Science, Johann Wolfgang Goethe Universitaet, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); von Bremen, Lueder [ForWind - Center for Wind Energy Research, University of Oldenburg, Marie-Curie-Str. 1, D-26129 Oldenburg (Germany); Greiner, Martin [Corporate Research and Technology, Siemens AG, D-81730 Muenchen (Germany); Aarhus School of Engineering and Institute of Mathematical Sciences, Aarhus University, Ny Munkegade 118, 8000 Aarhus C (Denmark); Hoffmann, Clemens [Corporate Research and Technology, Siemens AG, D-81730 Muenchen (Germany); Speckmann, Markus; Bofinger, Stefan [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Koenigstor 59, D-34119 Kassel (Germany)
2010-11-15
The renewable power generation aggregated across Europe exhibits strong seasonal behaviors. Wind power generation is much stronger in winter than in summer. The opposite is true for solar power generation. In a future Europe with a very high share of renewable power generation those two opposite behaviors are able to counterbalance each other to a certain extent to follow the seasonal load curve. The best point of counterbalancing represents the seasonal optimal mix between wind and solar power generation. It leads to a pronounced minimum in required stored energy. For a 100% renewable Europe the seasonal optimal mix becomes 55% wind and 45% solar power generation. For less than 100% renewable scenarios the fraction of wind power generation increases and that of solar power generation decreases. (author)
Directory of Open Access Journals (Sweden)
Ben Minnaert
2017-09-01
Full Text Available Wireless power transfer from one transmitter to multiple receivers through inductive coupling is slowly entering the market. However, for certain applications, capacitive wireless power transfer (CWPT using electric coupling might be preferable. In this work, we determine closed-form expressions for a CWPT system with one transmitter and two receivers. We determine the optimal solution for two design requirements: (i maximum power transfer, and (ii maximum system efficiency. We derive the optimal loads and provide the analytical expressions for the efficiency and power. We show that the optimal load conductances for the maximum power configuration are always larger than for the maximum efficiency configuration. Furthermore, it is demonstrated that if the receivers are coupled, this can be compensated for by introducing susceptances that have the same value for both configurations. Finally, we numerically verify our results. We illustrate the similarities to the inductive wireless power transfer (IWPT solution and find that the same, but dual, expressions apply.
Regulation of Renewable Energy Sources to Optimal Power Flow Solutions Using ADMM: Preprint
Energy Technology Data Exchange (ETDEWEB)
Zhang, Yijian; Hong, Mingyi; Dall' Anese, Emiliano; Dhople, Sairaj; Xu, Zi
2017-03-03
This paper considers power distribution systems featuring renewable energy sources (RESs), and develops a distributed optimization method to steer the RES output powers to solutions of AC optimal power flow (OPF) problems. The design of the proposed method leverages suitable linear approximations of the AC-power flow equations, and is based on the Alternating Direction Method of Multipliers (ADMM). Convergence of the RES-inverter output powers to solutions of the OPF problem is established under suitable conditions on the stepsize as well as mismatches between the commanded setpoints and actual RES output powers. In a broad sense, the methods and results proposed here are also applicable to other distributed optimization problem setups with ADMM and inexact dual updates.
Yang, Chunhui; Su, Zhixiong; Wang, Xin; Liu, Yang; Qi, Yongwei
2017-03-01
The new normalization of the economic situation and the implementation of a new round of electric power system reform put forward higher requirements to the daily operation of power grid companies. As an important day-to-day operation of power grid companies, investment management is directly related to the promotion of the company's operating efficiency and management level. In this context, the establishment of power grid company investment management optimization system will help to improve the level of investment management and control the company, which is of great significance for power gird companies to adapt to market environment changing as soon as possible and meet the policy environment requirements. Therefore, the purpose of this paper is to construct the investment management optimization system of power grid companies, which includes investment management system, investment process control system, investment structure optimization system, and investment project evaluation system and investment management information platform support system.