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Short-term Scheduling of Generation Units Considering Effective Uncertainties and Their Economic Effects
, Ph.D. Dissertation Sharif University of Technology ; Ehsan, Mehdi (Supervisor) ; Amjady, Nima (Co-Advisor) ; Zareipour, Hamid Reza (Co-Advisor)
Abstract
The objective of the short-term scheduling of generation units has been changed with the restructuring of power systems. Minimizing the total operation cost while satisfying system operation constraints is the main objective of short-term scheduling of generation units in an integrated or centralized power system. Unlike the vertically integrated power systems, the main objective of Generation Company (GenCO) is maximizing the total profit in the restructured system. Two new approaches, called time varying acceleration coefficients iteration particle swarm optimization (TVAC-IPSO) and Imperialist Competitive Algorithm (ICA) are proposed to solve power systems static and dynamic economic...
Optimal reliable operation of hydrothermal power systems with random unit outages
, Article IEEE Transactions on Power Systems ; Volume 18, Issue 1 , 2003 , Pages 279-287 ; 08858950 (ISSN) ; Farrokhzad, D ; Modarres, M ; Sharif University of Technology
2003
Abstract
A new model for long-term operation of hydrothermal power systems is introduced and a method for obtaining an optimal solution is also developed. We assume that reservoir inflows and energy demand are stochastic and all units are exposed to random outages. The objective is to minimize the total cost of the system as well as the expected interruption cost of energy (EIC) during a given planning horizon. This goal is reached through determination of hydroplant discharges, thermal units energy output, and the system reliability level simultaneously. In fact, we integrate long-term hydrothermal system operation planning and system reliability determination in a unified model. Since the resulting...
Optimal Reliable Operation of Hydrothermal Power Systems with Random Unit Outages
, Article IEEE Power Engineering Review ; Volume 22, Issue 11 , 2002 , Pages 59- ; 02721724 (ISSN) ; Farrokhzad, D ; Modarres, M ; Sharif University of Technology
2002
Abstract
A new model for long-term operation of hydrothermal power systems is introduced, and a method for obtaining an optimal solution is developed. We assume both reservoir inflows and energy demand are stochastic and all units are exposed to random outages. The objective is to minimize the total cost of the system as well as the expected interruption cost of energy (EIC) during a given planning horizon. This goal is reached through simultaneous determination of hydro plant discharges, thermal units energy output, and the system reliability level. Long-term hydrothermal system operation planning and system reliability determination are integrated in a unified model. Since the resulting model is a...
Economic impact of price forecasting inaccuracies on self-scheduling of generation companies
, Article Electric Power Systems Research ; Volume 81, Issue 2 , February , 2011 , Pages 617-624 ; 03787796 (ISSN) ; Zareipour, H ; Ehsan, M ; Amjady, N ; Sharif University of Technology
2011
Abstract
This paper studies the economic impact of using inaccurate price forecasts on self-scheduling of generation companies (GenCos) in a competitive electricity market. Four alternative sets of price forecasts are used in this study which have different levels of accuracy. The economic impact of price forecast inaccuracies is calculated by comparing the economic benefits of the GenCos in two self-scheduling scenarios. In the first scenario, electricity market price forecasts are used to optimally schedule the GenCos' next day operation. In the second scenario, perfect price forecasts, i.e., actual market prices, are used for self-scheduling of the GenCos. Two indices are utilized to quantify the...
Cost-benefit analysis and MILP for optimal reserve capacity determination in power system
, Article Applied Mathematics and Computation ; Volume 196, Issue 2 , 2008 , Pages 752-761 ; 00963003 (ISSN) ; Ehsan, M ; Fotuhi Firuzabad, M ; Amjady, N ; Sharif University of Technology
2008
Abstract
In this paper, an approach for optimal determining reserve capacity in the electricity market is presented. This paper describes a method for setting the optimum value of reserve capacity based on the cost of its provision and the benefit derived from its availability. Reduction of customer outage cost is interpreted as the benefit of reserve capacity. In the proposed method, reserve is procured up to the point where the marginal cost of procuring reserve is equal to the marginal value of this reserve capacity. The proposed method can be formulated as a mixed-integer linear program (MILP) and solved with large-scale commercial solvers. The proposed method is applied to the IEEE reliability...
Application of information-gap decision theory to risk-constrained self-scheduling of GenCos
, Article IEEE Transactions on Power Systems ; Volume 28, Issue 2 , 2013 , Pages 1093-1102 ; 08858950 (ISSN) ; Zareipour, H ; Amjady, N ; Ehsan, M ; Sharif University of Technology
2013
Abstract
In a competitive electricity market, a generation company (GenCo) optimizes its operation schedules, referred to as self-scheduling, in order to maximize its profit. However, various sources of uncertainty, such as market price fluctuations or forced outage of generating units, may impact the GenCo's profit. In this paper, a non-probabilistic information-gap model is proposed to model the uncertainties in short-term scheduling of a GenCo. The self-scheduling problem is formulated for risk-neutral, risk-averse, and risk-seeker GenCos. Robustness of the decisions against low market prices are evaluated using a robustness model. Furthermore, windfall higher profit due to unpredicted higher...
Fabrication and Characterization of a UF Ceramic Membrane based on TiO_2 Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
UF membranes are widely used in various industries now, a major type of these membranes are ceramic membranes which are resistant to high temperatures and corrosive fluids. In this thesis we developed an anisotropic UF ceramic membrane based on 20nm TiO2 nanoparticles on a prous sustrate. We had two major challenges, the first one was to find a suitable prous substrate and the second one was to find an appropriate coating method. Our main task was to optimise the process conditions to achive a crackless and uniform membrane layer with minimal ups and downs. Lots of coating methods and TiO2 inks have been tried, finally we used a coating method which we called it “Soft Blade Coating”, with...
Continuous-thrust Trajectory Optimization in the Binary Asteroids System
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the...
Fabrication and Characterization of Inverted Perovskite Solar Cells Using Nickel Oxide as Hole Transporting Layer
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
In this research, we study and optimize the inverted perovskite solar cells (PSCs) using nano layers of NiOx and Li:NiOx as hole transporting layers (HTLs) and nano layers of PC70BM and C60 as electron transporting layers (ETLs). We fabricated inverted PSCs with three different HTLs, namely MoOx, PEDOT:PSS and NiOx, using vapor assisted solution processed (VASP) method for making MAPbI3 perovskite which yielded a power conversion efficiency (PCE) of 1%, 1.93% and 3.65%, respectively. Solution-processed deposition method, high transparency (˃90%) and high band gap (3.9 eV) are the most advantages to use NiOx as HTL in current research. Using lithium as dopant to the NiOx increases the...
Coupled Rotational and Translational Modelling of Two Satellite Tethered Formation and their Robust Attitude Control
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
The 6DOF modelling and robust attitude control of two tethered satellites using tether tension moments is studied in this thesis. In this regard, the coupled rotational and translational dynamics of two satellites connected by a tether in the presence of Earth’s gravitational perturbation, aerodynamic drag, solar radiation pressure and third body effects (Sun and Moon) and also uncertainties in some of physical parameters of system and sensor’s outputs is modelled. Moreover, the tether attachment point to the satellites is different from their center of mass and its effect on dynamics of the system is taken into consideration. Then, the attitude of both satellites are controlled using robust...
Fault Tolerant Model Predictive Control of Tethered Satellite System
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this thesis, a control method to cope with the fault in the two-satellite two-tether satellite systems has been proposed to avoid failing the mission in the case one tether is torn. A new model for the tethered satellite system with two tethers has been developed to show the effects of tethers’ tension forces in the attitude dynamics. One of the main features of this model is the ability of changing the tethers’ connection points to the co-satellite for attitude control purposes. As a result, tethers’ tension forces are used as control actions to reduce the fuel consumption. The introduced coupled tethered satellite system has been controlled using the model predictive control method....
Fault-Tolerant Attitude Control of Satellite with Thrusters Using μ-synthesis
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
In this project, a fault-tolerant attitude control system is developed for thruster-driven satellites. The proposed method has the advantage over current state-of-the-art approaches in that it does not require a fault detection and isolation system. Generalized moments are generated by a robust controller that is designed using mixed sensitivity H_∞ and μ-synthesis by DK-iteration. Moreover, a pulse-width modulation technique with quadratic programming optimization is tuned to map the controller outputs to thruster on-off commands as efficiently as possible. The controller is designed to tolerate up to ±30% perturbations in inertia properties and thrust degradations up to 90% of the nominal...
Integrated Control and Estimation of Satellite Attitude using Adaptive Nero-Fuzzy Inference System
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
This paper presents an integrated attitude control and estimation of satellite by using adaptive neural fuzzy (ANFIS) logic, indeed a system which using ANFIS controller and estimator is considered then an ANFIS simulator that can control and estimate contemporary is supposed. ANFIS system has been trained by using data obtained from an optimal PID controller. Then ANFIS controller performance has been compared with the performance of a PID controller, the analogy has repeated in different situations such as noise and uncertainty. Results show that system with ANFIS controller is more optimal than PID’s in all these situations. After that ANFIS estimator is studied and results indicate the...
Dynamics of Tethered Satellite Formation Around Binary Asteroids
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
Studying of binary asteroids because of achieving data of existence sources in the world persuades to investigate about tethered satellite formation around binary asteroids in future missions. About 20 percent of asteroids around the sun are binary asteroids. It is going to analyse dynamics of tethered satellite around Didymos binary asteroid. Light mass of the asteroid is good reason to consider gravitational harmonic perturbation, and leads to attention about solar radiation pressure depends on distance in modelling of the dynamical system. It will be zonal harmonics up to second order and sectoral. Satellites are such a particle as an assumption; that is why attitude motion of satellites...
Fractional Order Modeling and Control of Flexible Satellite
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
In recent decades the structure of space systems has gained more complexity due to the development of space technology. Usage of larger structure in spacecraft could cause undesirable structural vibration. mNeglecting this phenomena would affect the performance of satellite subsystems specially the accuracy of satellite control subsystem. By implementing fractional order calculus in modeling of flexible satellite, the damping effect could be modeled better than classical damping model. Also using fractional order integrator and differentiator operator will increase the performance of control subsystem. In this research, the fractional order calculus has been used in modeling and control of...
Spacecraft Rendezvous and Docking Using Adaptive Neuro-Fuzzy Inference System
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this research an ANFIS controller will be developed to rendezvous and dock with a non-cooperative spacecraft; the controller must make the spacecraft reach the velocity and nearby position of the target spacecraft. Due to uncertainty in modeling and changes in the moment inertia tensor, the controller must be able to adapt with these changes and uncertainty, these changes may happen because of robotic arm or solar panel movings. Robustness of the controller will be evaluated by applying orbital disturbances and modeling errors through monte-carlo simulations. To model the spacecraft the specifications of a known spacecraft will be used but some specifications may be studied parametricaly....
Attitude and Deformation Estimation of Flexible Satellite Using Magnetometer and Sun Sensor
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
The estimation of attitude and deformation of a flexible satellite using magnetometer and sun sensor data are studied in this thesis. To this end, the dynamical differential equations of the flexible satellite have been derived using Lagrange’s equation. These equations of motion are then utilized for the purpose of simulation and verification. After introducing the measurements equations, the observability of the satellite with flexible panels has been evaluated. Afterward, the attitude of the satellite body and deformation of the flexible panels have been estimated by EKF (Extended Kalman Filter) as well as UKF (Unscented Kalman Filter). The results show that the estimations using UKF are...
Optimal Control of Spacecraft on the Earth-Moon Lagrange Point Orbits considering Sun and other Planets and Elliptic Orbit Perturbations
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
In this thesis, optimal station keeping of spacecraft on the closed-orbits near the Earth-Moon Lagrange points has been investigated. Lagrange points L1 and L2 are unstable equilibrium points of the circular restricted three-body problem (CRTBP), and periodic orbits near them are the destination of modern missions. However, perturbations resulting from the gravitational forces of the Sun and the planets and the eccentricity of the orbit of the Moon around the Earth make the Lagrange point unstable, even L4 and L5, which are stable in CRTBP. The most suitable choice for spacecraft mission near the collinear Lagrange points is the Halo and other closed-orbits around them, which need...
Orbit Design and Optimization of Satellite Constellation for Regional Coverage
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
In this thesis, the satellite constellation orbit design for regional coverage is investigated. The orbits of satellites in a constellation for Earth observation missions play a crucial role in performance and characteristics of the mission; for example the image resolution, the area of coverage, and the coverage interval. In this thesis the problem is to find the optimal initial orbital elements for meeting the earth observation mission objectives for one or several sites. The cost functions are the total coverage time, the maximum gap time, time average gap, altitude, and number of satellites. The problem is solved in a multi-objective manner for different combination of two of the above...
Autonomous Orbit Estimation for Regional Navigation Satellites
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this thesis, autonomous orbit estimation of regional navigation satellites has been investigated. Estimation of satellite orbit is an integral part of satellite navigation, which may be executed via assistance of ground station. As the satellite is exposed to the ground station view, range, direction and rate of range is measured by mean of ranging instrumentation relative to ground reference, hence the precise position is calculated. In this thesis a set of satellites are investigated in a unique structure called constellation with the purpose of navigation. The occurrence which is likely to happen in this condition, is the failure of ground station under certain circumstances or losing...