Loading...
Search for:
load-flow
0.007 seconds
Total 65 records
Transmission Expansion Planning Considering Uncertainty in Generation and N-1 Criterion
, M.Sc. Thesis Sharif University of Technology ; Ehsan , Mehdi (Supervisor)
Abstract
In order to reduce investment and operation costs of the power systems, transmission expansion planning is inevitable. In fact, transmission expansion planning is to determine when, where and how many lines need to be added to power system with a minimum of investment and operating costs. In this thesis, transmission expansion planning has been performed at uncertainty in generation and N-1 criterion condition where uncertainty in generation means uncertainty in the moment of adding power plant to power system. In previous studies, transmission expansion planning was performed with DC-load flow in which, the power loss and voltage profiles were ignored due to the approximation in the...
Model Predictive Controller Design for Regenerative Electronic AC Load
, M.Sc. Thesis Sharif University of Technology ; Zolghadri, MohammadReza (Supervisor)
Abstract
Generally, virtual loads is used to test all AC power and energy meters and are usually passive. To prevent possible damage of this heat and to control the temperature, cooling blowers are used which increases the volume and weight. So, recycling the power delivered from the grid causes a small amount of power to be converted to heat in proportion to the load efficiency. The purpose of this study is design, predictive controller model for programmable electronic regenerative AC load. The structure used is a back-to-back converter consisting of an AC-DC converter and a DC-AC converter, which according to existence of capacitance between these two structures, two converters can be controlled...
Design and Implementation of Three Phase Regenerative Electronic AC Load
, M.Sc. Thesis Sharif University of Technology ; Zolghadri, Mohammd Reza (Supervisor)
Abstract
Three-phase electronic loads are used to test the performance of various electrical devices such as power supplies, generators, and transformers. Conventional electronic loads are composed of passive components that consume the energy, so have low power density and efficiency and to manage the produced heat, massive cooling systems are required. Nowadays, to increase efficiency and power density, three-phase regenerative electronic AC loads have been developed. To return energy to the grid and control the input power factor, the structure of these loads is based on back-to-back converters. In this project, a 35 kVA three-phase regenerative electronic AC load is designed. To control the power...
A decomposed solution to multiple-energy carriers optimal power flow
, Article IEEE Transactions on Power Systems ; Vol. 29, issue. 2 , March , 2014 , p. 707-716 ; ISSN: 8858950 ; Abbaspour, A ; Fotuhi-Firuzabad, M ; Hajipour, E ; Sharif University of Technology
Abstract
Presence of energy hubs in the future vision of energy networks creates a great opportunity for system planners and operators to move towards more efficient systems. The role of energy hubs as the intermediate in multi-carrier energy (MCE) systems calls for a generic framework to study the new upcoming technical as well as economical effects on the system performance. In response, this paper attempts to develop a general optimization and modeling framework for coupled power flow studies on different energy infrastructures. This, as a large-scale nonlinear problem, is approached through a robust optimization technique, i.e., multi-agent genetic algorithm (MAGA). The proposed procedure...
Probabilistic load flow in correlated uncertain environment using unscented transformation
, Article IEEE Transactions on Power Systems ; Vol. 27, issue. 4 , 2012 , p. 2233-2241 ; ISSN: 08858950 ; Fotuhi-Firuzabad, M ; Aminifar, F ; Sharif University of Technology
Abstract
As a matter of course, the unprecedented ascending penetration of distributed energy resources, mainly harvesting renewable energies, is a direct consequence of environmental concerns. This type of energy resource brings about more uncertainties in power system operation and planning; consequently, it necessitates probabilistic analyses of the system performance. This paper develops a new approach for probabilistic load flow (PLF) evaluation using the unscented transformation (UT) method. The UT method is recognized as a powerful approach in assessing stochastic problems with/without correlated uncertain variables. The capability of the UT method in modeling correlated uncertain variables is...
Probabilistic assessment and sensitivity analysis of marginal price of different services in power markets
, Article IEEE Systems Journal ; Volume 7, Issue 4 , May , 2013 , Pages 873-880 ; 19328184 (ISSN) ; Afkousi-Paqaleh, M ; Hosseini, S. H ; Sharif University of Technology
2013
Abstract
Different sources of uncertainty in power systems, i.e., the uncertainties associated with bus loading and component availability is reflected in uncertainties in different system variables through system physical and economical relationships. A stochastic power flow algorithm can be used to model the stochastic nature of power systems. The algorithm introduced in this paper calculates the probability density function (pdf) of marginal prices of different market services. These pdfs provide the market participant with some valuable information to reduce the risk of their decisions and actions. The algorithm linearizes the optimal power flow formulation and uses the Gram-Charlier method to...
Modified artificial bee colony algorithm based on fuzzy multi-objective technique for optimal power flow problem
, Article Electric Power Systems Research ; Volume 95 , 2013 , Pages 206-213 ; 03787796 (ISSN) ; Hosseinian, S. H ; Ghazanfari, A ; Sharif University of Technology
2013
Abstract
This paper presents a fuzzy based modified artificial bee colony (MABC) algorithm to solve discrete optimal power flow (OPF) problem that has both discrete and continuous variables considering valve point effects. The OPF problem is formulated as a multi-objective mixed-integer nonlinear problem, where optimal settings of the OPF control variables for simultaneous minimization of total fuel cost of thermal units, total emission, total real power losses, and voltage deviation are obtained. The proposed approach is applied to the OPF problem on IEEE 30-bus and IEEE 118-bus test systems. The performance and operation of the proposed approach is compared with the conventional methods. The...
Probabilistic load flow in correlated uncertain environment using unscented transformation
, Article IEEE Transactions on Power Systems ; Volume 27, Issue 4 , 2012 , Pages 2233-2241 ; 08858950 (ISSN) ; Fotuhi Firuzabad, M ; Aminifar, F ; Sharif University of Technology
2012
Abstract
As a matter of course, the unprecedented ascending penetration of distributed energy resources, mainly harvesting renewable energies, is a direct consequence of environmental concerns. This type of energy resource brings about more uncertainties in power system operation and planning; consequently, it necessitates probabilistic analyses of the system performance. This paper develops a new approach for probabilistic load flow (PLF) evaluation using the unscented transformation (UT) method. The UT method is recognized as a powerful approach in assessing stochastic problems with/without correlated uncertain variables. The capability of the UT method in modeling correlated uncertain variables is...
The effect of fuel cell operational conditions on the water content distribution in the polymer electrolyte membrane
, Article Renewable Energy ; Volume 36, Issue 12 , December , 2011 , Pages 3319-3331 ; 09601481 (ISSN) ; Roshandel, R ; Sharif University of Technology
2011
Abstract
Models play an important role in fuel cell design and development. One of the critical problems to overcome in the proton exchange membrane (PEM) fuel cells is the water management. In this work a steady state, two-dimensional, isothermal model in a single PEM fuel cell using individual computational fluid dynamics code was presented. Special attention was devoted to the water transport through the membrane which is assumed to be combined effect of diffusion, electro-osmotic drag and convection. The effect of current density variation distribution on the water content (λ) in membrane/electrode assembly (MEA) was determined. In this work the membrane heat conductivity is considered as a...
Probabilistic assessment of available transfer capacity via market linearization
, Article IEEE Systems Journal ; Volume 9, Issue 4 , August , 2015 , Pages 1409-1418 ; 19328184 (ISSN) ; Nouri, A ; Salmanpor Bandaghiri, P ; Saeedavi, R ; Afkousi Paqaleh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Uncertainties associated with bus loading and components' availability lead to uncertainties in different system variables based on the system physical and economical relationships. Line flows, bus voltages, different prices, and other variables and indices, such as available transfer capacity (ATC), are stochastic and cannot be expressed as a determined quantity. Traditionally, in order to model the stochastic nature of power systems, a stochastic power flow algorithm is used. In this paper, stochastic-algebraic method is applied to find the probability density function (pdf) of ATC. The algorithm linearizes the optimal power flow formulation and uses Gram-Charlier expansion to find the pdf...
Stochastic Reconfiguration and Optimal Coordination of V2G Plug-in Electric Vehicles Considering Correlated Wind Power Generation
, Article IEEE Transactions on Sustainable Energy ; Volume 6, Issue 3 , 2015 , Pages 822-830 ; 19493029 (ISSN) ; Niknam, T ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper investigates the optimal operation of distribution feeder reconfiguration (DFR) strategy in the smart grids with high penetration of plug-in electric vehicles (PEVs) and correlated wind power generation. The increased utilization of PEVs in the system with stochastic volatile behavior along with the high penetration of renewable power sources such as wind turbines (WTs) can create new challenges in the system that will affect the DFR strategy greatly. In order to reach the most efficiency from the PEVs, the idea of vehicle-to-grid (V2G) is employed in this paper to make a bidirectional power flow (either charging/discharging or idle mode) strategy when providing the main charging...
Security constrained unit commitment with flexibility in natural gas transmission delivery
, Article Journal of Natural Gas Science and Engineering ; Volume 27, Part 2 , November 2015 , 2015 , Pages 632–640 ; 18755100 (ISSN) ; Kazemi, M ; Ehsan, M ; Sharif University of Technology
Elsevier
2015
Abstract
This paper presents a formulation of fuzzy optimization for uncertainties in natural gas in fuel constraints for hourly individual unit and total unit fuel consumptions. Security Constrained Unit Commitment (SCUC) is usually a mixed integer programming and gas load flow has a non-linear equation a genetic algorithm is proposed to solve natural gas transmission network. A fuzzy mixed integer programming optimization is briefly discussed and adapted to deal with security constrained unit commitment schedule. Finally, two case studies are investigated (IEEE 6-bus system with 7-node natural gas transmission grid and the IEEE 118-bus power system linked with 14-node gas transmission test system)...
Probabilistic optimal power flow in correlated hybrid wind-PV power systems: A review and a new approach
, Article Renewable and Sustainable Energy Reviews ; Volume 41 , January , 2015 , Pages 1437-1446 ; 13640321 (ISSN) ; Rashidinejad, M ; Firuz Abad, M. F ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Hastening the power industry reregulation juxtaposed with the unprecedented utilization of uncertain renewable energies (REs), faces power system operation with sever uncertainties. Consequently, uncertainty assessment of system performance is an obligation. This paper reviews the probabilistic techniques used for probabilistic optimal power flow (P-OPF) studies and proposes a novel and powerful approach using the unscented transformation (UT) method. The heart of the proposed method lies in how to produce the sampling points. Appropriate sampling points are chosen to perform the P-OPF with a high degree of accuracy and less computational burden compared with features of other existing...
Optimal distributed static series compensator placement for enhancing power system loadability and reliability
, Article IET Generation, Transmission and Distribution ; Volume 9, Issue 11 , 2015 , Pages 1043-1050 ; 17518687 (ISSN) ; Fotuhi Firuzabad, M ; Aminifar, F ; Safdarian, A ; Lehtonen, M ; Sharif University of Technology
Institution of Engineering and Technology
2015
Abstract
Distributed static series compensator (DSSC) is a member of the family of distributed flexible AC transmission system devices that can be attached directly to conductors of transmission lines. DSSCs are able to compensate for and adjust the line reactance; thus, they could be widely used in stability-limited transmission systems. Owing to economic matters, the optimal placement of DSSCs is of a great interest from practical viewpoints. This study presents an approach to find the optimal locations of DSSCs to enhance the system loadability and reliability using the DC load flow model. The optimisation problem is solved using the mixed-integer linear programming. A compromise between improving...
A framework for compromising between power generation cost and power system security in regulated market using MO-OPF
, Article EPEC 2010 - IEEE Electrical Power and Energy Conference: "Sustainable Energy for an Intelligent Grid", 25 August 2010 through 27 August 2010 ; 2010 ; 9781424481880 (ISBN) ; Sotoodeh, P ; Khosravi, H ; Pishvaie, M ; Sharif University of Technology
Abstract
Transmission line congestion in electricity market is lead to increase the energy cost and change in local marginal prices. So, it is probable that the market power is manifested. Market power may prevent the full competition in Electricity Market. Moreover, in this condition, with operating of power system in its boundary conditions, the system may be damaged and the security of the system may be disturbed. On the other hand, decreasing the line flows from their optimal value, cost and consequently, price of energy are increased. So, there is need to have a compromise between the line flow decrease and the cost those impose. In this paper, a framework for compromising between social cost...
Locating and parameters setting of unified power flow controller for congestion management and improving the voltage profile
, Article Asia-Pacific Power and Energy Engineering Conference, APPEEC, 28 March 2010 through 31 March 2010 ; March , 2010 ; 21574839 (ISSN) ; 9781424448135 (ISBN) ; Ehsan, M ; Sharif University of Technology
2010
Abstract
This paper propose a particle swarm optimization based algorithm for locating Unified power flow controller (UPFC), as well as set its parameters, with static point of view in deregulated electricity markets in order to reduce generation cost, voltage violation and manage congestion. The modeling of UPFC has been adapted based on power injection method. In order to verify and validate the effectiveness of the proposed method, it was applied to 24-bus Reliability Test System (RTS) and the results have been discussed
A dynamic programming-based heuristic approach for optimal transmission switching problem with N-1 reliability criterion
, Article 2016 International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2016 - Proceedings, 16 October 2016 through 20 October 2016 ; 2016 ; 9781509019700 (ISBN) ; Jooshaki, M ; Hosseini, S. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Minimization of operating costs is one of the most important objectives of power system operators. To achieve this goal, several optimization problems such as unit commitment and optimal power flow have been introduced. Historically, in these problems, the transmission network has been considered as a static system, i.e., the ability of transmission lines switching is not modeled. On the other hand, it has been shown that transmission line switching can significantly reduce operating costs by the means of topology modification. However, considering this capability, a large number of binary variables are introduced in the objective function, and as a consequence, the computation time will be...
Smart power management of DC microgrids in future milligrids
, Article 2016 18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe, 5 September 2016 through 9 September 2016 ; 2016 ; 9789075815245 (ISBN) ; Mokhtari, H ; Davari, P ; Loh, P. C ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper a novel droop approach for power management in low voltage dc MicroGrids (MGs) based on a master-slave concept is presented. A virtual frequency is injected by a master unit, which is proportional to its output power. Other slave units determine their output power according to the corresponding frequency based droop characteristics. Unlike the dc voltage-droop methods, the proposed virtual frequency-droop approach can be smartly applied for proportional power management among the energy units and loads as well as adding zero net energy capability to the MG. Both power flow and energy flow can be performed without utilizing an extra communication system. Simulation results...
Application of bat optimization algorithm in optimal power flow
, Article 24th Iranian Conference on Electrical Engineering, ICEE 2016, 10 May 2016 through 12 May 2016 ; 2016 , Pages 793-798 ; 9781467387897 (ISBN) ; Seyf Abad, M. S ; Seifi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, Bat Algorithm is proposed to solve the Optimal Power Flow (OPF) problem. The approach employs a Meta heuristic optimization algorithm called bat optimization algorithm to determine the optimal settings of control variables of OPF problem. The performance of proposed method examined on the IEEE 9, 14, 30 and 57-buses test systems with fuel cost minimization as the objective function. The numerical results are compared to those of Particle Swarm Optimization (PSO), Harmony Search (HS) and Cuckoo algorithms. Simulation results obtained from the proposed approach demonstrate that this method provide effective and robust high-quality answer for the OPF problem. © 2016 IEEE
Multi-body simulation of a flapping-wing robot using an efficient dynamical model
, Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 38, Issue 1 , 2016 , Pages 133-149 ; 16785878 (ISSN) ; Selk Ghafari, A ; Ebrahimi, A ; Meghdari, A ; Sharif University of Technology
Springer Verlag
Abstract
The aim of this article is to present an efficient dynamical model for simulating flapping robot performance employing the bond graph approach. For this purpose, the complete constitutive elements of the system under investigation, including the main body and accessories, flapping mechanism, flexible wings and propulsion system consisting of a battery, DC motors and gear boxes, are considered. A complete model of the system was developed appending bond graph models of the subsystems together utilizing appropriate junctions. The wings were also modeled using ANSYS only for an initial evaluation. Moreover, a computer model was developed employing the block-oriented structure of Simulink in...