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Latecomer firm strategies in complex product systems (CoPS): The case of Iran's thermal electricity generation systems
, Article Research Policy ; Volume 44, Issue 6 , July , 2015 , Pages 1240-1251 ; 00487333 (ISSN) ; Hobday, M ; Hamedi, M ; Sharif University of Technology
Elsevier
2015
Abstract
This paper examines the strategies of a local supplier of high technology capital goods (or complex product systems, CoPS) in a middle-income developing economy, Iran, in its efforts to acquire technology and catch up with market leaders. The study draws upon both the development and business strategy literatures to develop a novel conceptual framework of latecomer strategy which is then applied to the Iranian firm engaged in the design, production and implementation of electricity generation systems. Although exploratory, the study shows that the firm was able to exploit its linkages with local clients, favorable government policies and a growing domestic demand to overcome barriers to...
A novel straightforward unit commitment method for large-scale power systems
, Article IEEE Transactions on Power Systems ; Volume 22, Issue 4 , 2007 , Pages 2134-2143 ; 08858950 (ISSN) ; Khodaei, A ; Aminifar, F ; Sharif University of Technology
2007
Abstract
In this paper, a novel fast straightforward method for thermal generating units scheduling is presented. The new method decomposes the solution of the unit commitment (UC) problem into three subproblems. In the first subproblem, the quadratic cost functions of units are linearized and hourly optimum solution of UC is obtained considering all constraints except the minimum up/down time constraints. In the second subproblem, the minimum up/down times are enforced through a novel optimization process by modifying the schedule obtained in the first step. Finally, in the third subproblem, the extra reserve is minimized using a new decommitment algorithm. For testing the proposed method, the...
Thermodynamic and environmental consideration of advanced gas turbine cycles with reheat and recuperator
, Article International Journal of Environmental Science and Technology ; Volume 4, Issue 2 , 2007 , Pages 253-262 ; 17351472 (ISSN) ; Ghofrani, M. B ; Sharif University of Technology
CEERS
2007
Abstract
The role of gas turbine power plants in electrical energy production has been considerably increased in the last two to three decades. Various methods have been proposed to improve the performance of gas turbine cycles. In this research, two methods, a reheat cycle and a cycle with a reheat and a recuperator, were investigated and compared with a simple cycle. The main objective of this paper is to study the performance of an simple cycle and reheat cycle under actual conditions. In this regard, all processes are treated as actual, and in particular a relatively simple and reliable approach is used to predict the amount of cooling air. The results obtained on the basis of a model developed...
Short-term market power assessment in a long-term dynamic modeling of capacity investment
, Article IEEE Transactions on Power Systems ; Volume 28, Issue 2 , October , 2013 , Pages 626-638 ; 08858950 (ISSN) ; Hosseini, S. H ; Sharif University of Technology
2013
Abstract
This paper proposes a dynamic time simulation model for long-term generation capacity investment decisions in the presence of either perfect or imperfect electricity market. The model is based on system dynamics concept in which the dynamics of capacity construction is traced using the forecast of electricity price cleared in the short-term electricity market. Both the perfect and oligopolistic competitions are considered and a market power index is defined to evaluate the competition level of the electricity market. The short-term and long-term dynamic analysis are used to represent the generation firms' behavior in bidding strategy and capacity investment, respectively. Both possibilities...
Day-ahead self-scheduling of a transmission-constrained GenCo with variable generation units using the incomplete market information
, Article IEEE Transactions on Sustainable Energy ; Volume 8, Issue 3 , 2017 , Pages 1260-1268 ; 19493029 (ISSN) ; Ehsan, M ; Shahidehpour, M ; Sharif University of Technology
Abstract
In this paper, a self-generation scheduling method for a power generation company (GenCo) with renewable generation units is presented. In the proposed method, locational market prices (LMPs) are calculated using the incomplete information on competing market participants by simulating the ISO's market clearing program and considering the effect of physical limitations of transmission lines. The errors associated with forecasted LMP and renewable production are modeled in the GenCo's generation scheduling using a robust optimization approach. The scheduling problem is modeled as a mixed-integer linear programming which is solved by a CPLEX solver in GAMS. An eight-bus system is employed to...
Fuzzy economic dispatch and spinning reserve allocation using evolutionary programming
, Article 40th North American Power Symposium, NAPS2008, Calgary, AB, 28 September 2009 through 30 September 2009 ; 2008 ; 9781424442836 (ISBN) ; Motamedi, A ; Sadati, N ; Fallahi, K ; Fathi, B ; Sharif University of Technology
2008
Abstract
The objective of economic dispatch (ED) problem is minimizing the operating cost and finding the point where the total output of the generations equals the total power that must be delivered. In that point the incremental cost of power generation is also equal for all generators. Considering the presence of uncertainty and inaccuracy in the data, fuzzy set theory is an appropriate method to solve the economic dispatch problems. In this paper, a modified fuzzy economic dispatch is formulated to solve the problem under the competitive electricity market uncertainties. Also, available spinning reserve is optimally allocated to market participants. The formulated optimization problem it then...
New approach to bidding strategies of generating companies in day ahead energy market
, Article Energy Conversion and Management ; Volume 49, Issue 6 , 2008 , Pages 1493-1499 ; 01968904 (ISSN) ; Ranjbar, A. M ; Shirani, A. R ; Sharif University of Technology
2008
Abstract
In the restructured power systems, generating companies (Genco) are responsible for selling their product in the energy market. In this condition, the question is how much and for what price must each Genco generate to maximize its profit. Therefore, this paper intends to propose a rational method to answer this question. In the proposed methodology, the hourly forecasted market clearing price (FMCP) is used as a reference to model the possible and probable price strategies of Gencos. The forecasted price is the basis of the bidding strategies of each Genco, which can be achieved by solving a bi-level optimization problem using GAMS (general algebraic modeling system) language. The first...
Impacts of load pattern variation in Iran power system on generation system planing
, Article Canadian Conference on Electrical and Computer Engineering 2005, Saskatoon, SK, 1 May 2005 through 4 May 2005 ; Volume 2005 , 2005 , Pages 2216-2219 ; 08407789 (ISSN) ; Gharagozloo, H ; Fotuhi Firuzabad, M ; Farrokhzad, D ; Sharif University of Technology
2005
Abstract
During last decade, the electricity demand in Iran grows up more than 8% per year due to an increasing economic growth. The main part of this load growth is related to industrial and agricultural demand. At this period, electric utilities tried to provide the peak load demand using all different types of available generating units especially with hydro generation plants. However, moving the time of peak demand occurring from night hours to day time and also increasing of load demand at mid day hours, created a new challenge to hydro-generation planning. As the number of daily peak hours increases from the nightly to daily peak hours and considering that Iran is a sub-tropical country, use of...
An analytical method for the reliability evaluation of wind energy systems
, Article TENCON 2005 - 2005 IEEE Region 10 Conference, Melbourne, 21 November 2005 through 24 November 2005 ; Volume 2007 , 2005 ; 21593442 (ISSN); 0780393112 (ISBN); 9780780393110 (ISBN) ; Fotuhi, M ; Abbaspour, A ; Ranjbar, A. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2005
Abstract
Wind generation is one of the most successful sources of renewable energy for the production of electrical energy. The technical characteristics of wind generation make existing conventional generation models not directly applicable. This paper presents an analytical method for the reliability assessment of the flat-rated wind turbine generation systems. An example of flat rating is that of the MOD-2, a second-generation class of wind turbines. The power-velocity characteristic of the flat-rated wind turbines is employed in this paper to model the operating behavior of the installed wind turbine generators. For wind-power potential estimation, the Weibull distribution model is used. The...
Liquid soap film generates electricity: a suspended liquid film rotating in an external electric field as an electric generator
, Article Microfluidics and Nanofluidics ; Vol. 18, issue. 1 , Apr , 2014 , pp. 141-147 ; ISSN:16134982 ; Feiz, M. S ; Namin, R. M ; Sharif University of Technology
Abstract
We have observed that a rotating liquid soap film generates electricity when placed between two non-contact electrodes with a sufficiently large potential difference. In our experiments, suspended liquid film (water + soap film) is formed on the surface of a circular frame, which is forced to rotate in the x−y horizontal plane by a motor. This system is located at the center of two capacitor-like vertical plates to apply an external electric voltage difference in the x-direction. The produced electric current is collected from the liquid film using two conducting electrodes that are separated in the y-direction. We previously reported that a liquid film in an external electric field rotates...
Effects of wind turbines on voltage profile
, Article International Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2011 and Electromotion 2011 Joint Conference ; Sept , 2013 , Pages 64-68 ; 9781467350037 (ISBN) ; Ehsan, M ; Afsharirad, H ; Nazaraliloo, M ; Sharif University of Technology
2013
Abstract
For distribution grids connected wind power generation, voltage quality is an important issue for the system planning purpose. The operation of wind turbines in the distribution networks may affect the voltage quality offered to the consumers. One of the most important considerations is the effect on the voltage profile, i.e. the induced slow voltage variations, which are the subject of this paper. The wind turbines can be operated in two modes: constant-speed and variable-speed. Each one of these cases has different impact on steady state voltage of distribution grids. For evaluation of these impacts, we have simulated SCIG generator that works in constant-speed operation and DFIG generator...
Eddy current losses in brushless doubly-fed machines
, Article Proceedings of the 2011 3rd International Youth Conference on Energetics, IYCE 2011, 7 July 2011 through 9 July 2011 ; July , 2011 , Page(s): 1 - 5 ; 9781457714948 (ISBN) ; Jandaghi, B ; Oraee, A ; Saket, M. A ; Gorginpour, H ; Oraee, H ; Sharif University of Technology
2011
Abstract
The application of the brushless doubly-fed machine (BDFM) is in wind power generation in harsh conditions, where reliability is important. In this paper, eddy current losses in a BDFM in four categories: a) the rotor classic eddy current losses, b) stator classic eddy current losses, c) rotor excessive eddy current losses, and d) stator excessive eddy current losses, are calculated for single frequency of the rotor and double frequency of the stator magnetic fields
A survey on the effect of different kinds of wind turbines on power system stability
, Article 2010 1st International Nuclear and Renewable Energy Conference, INREC'10, 21 March 2010 through 24 March 2010 ; March , 2010 ; 9781424452149 (ISBN) ; Afsharnia, S ; Shahooei, Z ; Sharif University of Technology
2010
Abstract
Due to deterioration of fossil fuel and policy directives on greenhouse gas mitigation, wind power generation has been widely developed in recent years. This has raised many issues in terms of power system operation, dynamics, stability and etc. This paper reviews the effect of different kinds of wind turbines on power system stability. Since there are no existing surveys in this area, it provides a comprehensive overview in transient and dynamic stability. The contribution of this survey is to provide a comparison to determine which kinds of wind turbines is better from the system stability point of view. Furthermore, the effects of wind power generation with energy storage systems are...
Computational study on design parameters of a solar chimney
, Article International Conference on Sustainable Mobility Applications, Renewables and Technology, 23 November 2015 through 25 November 2015 ; 2015 ; 9781467395298 (ISBN) ; Raveshi, S ; Shahsavari, M ; Sedaghat, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
Today, the production of energy and electricity is one of the major concerns of mankind. Electricity generation by solar energy is considered as one of the alternatives to fossil fuels. Solar chimneys mechanism is based on a natural phenomenon. In this process the solar energy heat up the earth's surface and the surrounding air. Due to the density difference between cold air and warm air, heated air ascends and causes air circulation. In this study, mathematical modelling of solar chimney and governing equations of this system will be discussed. In order to validate the numerical results, upwind velocity in chimney has been compared with a reliable reference results. As well as, the...
Applying portfolio theory-based modified ABC to electricity generation mix
, Article International Journal of Electrical Power and Energy Systems ; Volume 80 , 2016 , Pages 356-362 ; 01420615 (ISSN) ; Mozafari, B ; Ranjbar, A. M ; Soleymani, S ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Portfolio theory has found its model in numerous engineering applications for optimizing the electrical generation mix of an electricity area. However, to have better performance of this theory, this paper presents a new heuristic method as known modified artificial bee colony (MABC) to portfolio optimization problem. Moreover, we consider both dis-patchable and non-dis-patchable constrains variables and energy sources. Note that the proposed MABC method uses a Chaotic Local Search (CLS) to enhance the self searching ability of the original ABC algorithm. Resulting, in this paper a portfolio theory-based MABC model that explicitly distinguishes between electricity generation (energy),...
Operational reliability studies of power systems in presence of energy storage systems
, Article IEEE Transactions on Power Systems ; 2017 ; 08858950 (ISSN) ; Abbaspour, A ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Abstract
This paper mainly focuses on operational reliability studies of modern power systems taking into consideration the effects of energy storage systems (ESSs). The aim is to develop a new evaluation tool to assess the effects of different factors such as penetration rate, operational strategies and capacities of the ESSs in determining the role of these systems as an operating reserve resource. In this regard, at first, some modifications are made to the PJM method aimed to precisely model the short-term variability in output generation of wind farms in reliability studies. Then, this algorithm is employed to examine the effects of ESSs operating strategies in operational reliability level of...
Heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder: review and experiments
, Article Applied Thermal Engineering ; Volume 120 , 2017 , Pages 257-268 ; 13594311 (ISSN) ; Nakhchi, M. E ; Sharif University of Technology
Abstract
This experimental work is an attempt to identify the most significant parameters influencing heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder. This type of flow known as Taylor-Couette flow has many industrial applications such as electrical power generators and rotating machineries. A comprehensive review of the previous works on flow regimes, heat transfer and pressure drop in grooved channels is provided. The experiments are conducted based on four different factors including Taylor number, 0
Operational reliability studies of power systems in the presence of energy storage systems
, Article IEEE Transactions on Power Systems ; Volume 33, Issue 4 , July , 2018 , Pages 3691-3700 ; 08858950 (ISSN) ; Abbaspour, A ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
This paper mainly focuses on operational reliability studies of modern power systems taking into consideration the effects of energy storage systems (ESSs). The aim is to develop a new evaluation tool to assess the effects of different factors such as penetration rate, operational strategies, and capacities of the ESSs in determining the role of these systems as a source of operating reserve. In this regard, at first, some modifications are made to the Pennsylvania-New Jersey-Maryland (PJM) method aimed to precisely model the short-term variability in output generation of wind farms in reliability studies. Then, this algorithm is employed to examine the effects of ESSs operating strategies...
Exergetic and thermoeconomic analysis of a trigeneration system producing electricity, hot water, and fresh water driven by low-temperature geothermal sources
, Article Energy Conversion and Management ; Volume 157 , 2018 , Pages 266-276 ; 01968904 (ISSN) ; Arefi, A. R ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Performance of a small-scale trigeneration system driven by low-temperature geothermal sources for producing fresh water, heating (hot water) and electricity is investigated from thermodynamic and economic standpoints. This system, utilizing a single stage absorption heat transformer leads to an increase in heat source temperature to be used in single stage evaporation desalination process and also providing water heating. Furthermore, an organic Rankine cycle is used for electric power generation. The developed model is validated with available data and effects of decision variables namely geothermal source, absorber and condenser temperatures on energy and exergy efficiencies of the...
Hybrid uncertainty-based offering strategy for virtual power plants
, Article IET Renewable Power Generation ; Volume 14, Issue 13 , 2020 , Pages 2359-2366 ; Ehsan, M ; Pozo, D ; Farrokhifar, M ; Sharif University of Technology
Institution of Engineering and Technology
2020
Abstract
This study proposes an optimal day-ahead (DA) electricity market offering model for a virtual power plant (VPP) formed by a mix of renewable distributed energy resources along with energy storage, such as electric vehicles. Two sources of uncertainty are considered, namely, wind power generation, modelled by an uncertainty set, and DA market price, modelled by scenarios. Opposite to classical robust optimisation approaches, the authors model maps minimal (worst-case) profits to a conservativeness parameter, while the classical robust optimisation maps conservativeness parameter to worst-case profits. In this regard, by using their optimisation framework, a VPP operator only deals with...