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load-frequency-control
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Delay compensation of demand response and adaptive disturbance rejection applied to power system frequency control
, Article IEEE Transactions on Power Systems ; Volume 35, Issue 3 , 2020 , Pages 2037-2046 ; Toulabi, M. R ; Salehi Dobakhshari, A ; Ashouri Zadeh, A ; Ranjbar, A. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In this paper, a modified frequency control model is proposed, where the demand response (DR) control loop is added to the traditional load frequency control (LFC) model to improve the frequency regulation of the power system. One of the main obstacles for using DR in the frequency regulation is communication delay which exists in transferring data from control center to appliances. To overcome this issue, an adaptive delay compensator (ADC) is used in order to compensate the communication delay in the control loop. In this regard, a weighted combination of several vertex compensators, whose weights are updated according to the measured delay, is employed. Generating the phase lead is the...
Designing Robust Dynamic Market Mechanism in Presence of Renewable Energy Uncertainty
, M.Sc. Thesis Sharif University of Technology ; Nasiri, Zahra (Supervisor) ; Ranjbar, Ali Mohammad (Supervisor)
Abstract
Power system operators are facing with imperative challenges to integrate high penetration of renewable power plants. The main challenge is required investment cost for accommodating the grid with uncertainties of renewable resources. In addition, intermittency and fluctuations of renewable resources are another challenges of system operators. Therefore, choosing a proper control procedure to respond the grid disturbances is a crucial task. However, the strategic behaviours of generation companies lead to a competition between them which affects the control performance. In this thesis, an integrated mechanism is proposed that consider both dynamic and strategic behaviours of generation...
Robust analysis and design of power system load frequency control using the Kharitonov's theorem
, Article International Journal of Electrical Power and Energy Systems ; Vol. 55, issue , 2014 , p. 51-58 ; Shiroei, M ; Ranjbar, A. M ; Sharif University of Technology
Abstract
This paper presents a robust decentralized proportional-integral (PI) control design as a solution of the load frequency control (LFC) in a multi-area power system. In the proposed methodology, the system robustness margin and transient performance are optimized simultaneously to achieve the optimum PI controller parameters. The Kharitonov's theorem is used to determine the robustness margin, i.e., the maximal uncertainty bounds under which the stable performance of the power system is guaranteed. The integral time square error (ITSE) is applied to quantify the transient performance of the LFC system. In order to tune the PI gains, the control objective function is optimized using the...
Power System Load Frequency Control in the Presence of Wind Turbines
, M.Sc. Thesis Sharif University of Technology ; Ranjbar, Ali Mohammad (Supervisor)
Abstract
This study presents the application of the doubly fed induction generator (DFIG) to reduce the frequency deviation and improve frequency of a power system. This has been done by proposing a wind turbine model and a new fuzzy controller. The fuzzy controller has been suggested to change the speed of the wind turbine rotor and modify the impacts of wind speed fluctuations on the output power. The fuzzy controller parameters are optimized using the genetic algorithm (GA) to achieve the appropriate transient response. A smart controller is combined with fuzzy controller to optimize the usage of wind turbine’s kinetic energy. Furthermore, the DFIG with the proposed controller participates in the...
Hierarchical optimal robust load-frequency control for power systems
, Article IET Generation, Transmission and Distribution ; Volume 6, Issue 4 , 2012 , Pages 303-312 ; 17518687 (ISSN) ; Sadati, N ; Sharif University of Technology
Abstract
In this study, a hierarchical optimal robust controller is presented for the power system load-frequency control problem. In this approach, the multi-area power system is first decomposed into several sub-systems (areas). Then by using a two-level control strategy, the overall optimal solution is obtained. At the first level, the optimal control of each area is obtained with respect to local information and also considering interactions coming from other areas. At the second level, by using a coordination strategy, the local controllers will converge to global solution and optimal robust controller is achieved. This approach is applicable to both single-area and multi-area interconnected...
Optimal tuning of temporary droop structure governor in the hydro power plant
, Article 2008 IEEE 2nd International Power and Energy Conference, PECon 2008, Johor Baharu, 1 December 2008 through 3 December 2008 ; 2008 , Pages 100-105 ; 9781424424054 (ISBN) ; Ranjbar, A. M ; Ansarimehr, P ; Borjian Boroujeni, S ; Sharif University of Technology
2008
Abstract
Load-frequency control is the intrinsic function of the governor in the power plants. It would be used in variant structures depend on the controller type such as PID, adaptive, fuzzy or robust. Temporary droop structure governor (TDSG) was commonly used in Hydro power plants (HPP). After representation of TDSG, this paper is dedicated to introducing a procedure for tuning TDSG parameters. The technique is based on pole placement for the closed loop poles of the system. These poles correspond to the TDSG parameters that by accurate tuning of them, pole placement is accomplished. The results for tuning TDSG of Abbaspour HPP have been presented as well. © 2008 IEEE
Robust multivariable predictive based load frequency control considering generation rate constraint
, Article International Journal of Electrical Power and Energy Systems ; Volume 46, Issue 1 , March , 2013 , Pages 405-413 ; 01420615 (ISSN) ; Toulabi, M. R ; Ranjbar, A. M ; Sharif University of Technology
2013
Abstract
In this paper, a robust multivariable Model based Predictive Control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area power system. The proposed control scheme is designed to consider multivariable nature of LFC, system uncertainty and generation rate constraint, simultaneously. A constrained MPC is employed to calculate optimal control input including generation rate constraints. Economic allocation of generation is further ensured by modification of the predictive control objective function. To achieve robustness against system uncertainty and variation of parameters, a linear matrix inequality (LMI) based approach is employed. To validate the...
Supervisory predictive control of power system load frequency control
, Article International Journal of Electrical Power and Energy Systems ; Vol. 61, issue , October , 2014 , p. 70-80 ; Ranjbar, A. M ; Sharif University of Technology
Abstract
Objective: The objective of this paper is to develop a hierarchical two-level power system load frequency control. Design: At the button level, standard PI controllers are utilized to control area's frequency and tie-line power interchanges. At the higher layer, model predictive control (MPC) is employed as a supervisory controller to determine the optimal set-point for the PI controllers in the lower layer. The proposed supervisory predictive controller computes the optimal set-points such that to coordinate decentralized local controllers. Blocking and coincidence point technology is employed to alleviate the computational effort of the MPC. In order to achieve the best closed loop...
Two-level optimal load-frequency control for multi-area power systems
, Article International Journal of Electrical Power and Energy Systems ; Volume 53, Issue 1 , December , 2013 , Pages 540-547 ; 01420615 (ISSN) ; Sadati, N ; Sharif University of Technology
2013
Abstract
In large-scale power systems, classical centralized control approaches may fail due to geographically distribution of information and decentralized controllers result in sub-optimal solution for load-frequency control (LFC) problems. In this paper, a two-level structure is presented to obtain optimal solution for LFC problems and also reduce the computational complexity of centralized controllers. In this approach, an interconnected multi-area power system is decomposed into several sub-systems (areas) at the first-level. Then an optimization problem in each area is solved separately, with respect to its local information and interaction signals coming from other areas. At the second-level,...
A functional model predictive control approach for power system load frequency control considering generation rate constraint
, Article International Transactions on Electrical Energy Systems ; Volume 23, Issue 2 , 2013 , Pages 214-229 ; 20507038 (ISSN) ; Ranjbar, A. M ; Amraee, T ; Sharif University of Technology
2013
Abstract
In this paper, a wide area measurement, centralized, load frequency control using model predictive control (MPC) is presented for multi-area power systems. A multivariable constrained MPC was used to calculate optimal control actions including generation rate constraints. To alleviate computational effort and to reduce numerical problems, particularly in large prediction horizon, an exponentially weighted functional MPC was employed. Time-based simulation studies were performed on a three-area power system, and the results were then compared with decentralized MPC and classical PI controller. The results show that the proposed MPC scheme offers significantly better performance against load...
Dynamic participation of wind farms in system frequency control
, Article IEEE PES Innovative Smart Grid Technologies Conference Europe, 14 October 2012 through 17 October 2012 ; October , 2012 ; 9781467325974 (ISBN) ; Ranjbar, A. M ; Karimi, H ; Shiroie, M ; Sharif University of Technology
2012
Abstract
In this paper, the participation of wind farms in load frequency control (LFC) is studied. A previously proposed macromodel for the wind farm is employed to regulate its output power. The wind farm including its proposed control strategy is incorporated into the conventional LFC model. The proposed LFC structure is able to dynamically maintain the system frequency at the nominal value against the power imbalances. To achieve proper transient response, the integral control parameter of the LFC controller is optimized using the genetic algorithm (GA). To verify the effectiveness of the proposed method, several simulation case studies are carried out. The results show that the wind farm can...
Load-frequency control of interconnected power system using emotional learning-based intelligent controller
, Article International Journal of Electrical Power and Energy Systems ; Volume 36, Issue 1 , March , 2012 , Pages 76-83 ; 01420615 (ISSN) ; Boroushaki, M ; Hosseini, S. H ; Sharif University of Technology
2012
Abstract
In this paper a novel approach based on the emotional learning is proposed for improving the load-frequency control (LFC) system of a two-area interconnected power system with the consideration of generation rate constraint (GRC). The controller includes a neuro-fuzzy system with power error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critic's stress is reduced. The convergence and performance of the proposed controller, both in presence and absence of GRC, are compared with those of proportional integral (PI), fuzzy logic (FL), and hybrid neuro-fuzzy (HNF)...
Application of intelligence-based predictive scheme to load-frequency control in a two-area interconnected power system
, Article Applied Intelligence ; Volume 35, Issue 3 , 2011 , Pages 457-468 ; 0924669X (ISSN) ; Hosseini, A. H ; Sharif University of Technology
2011
Abstract
This paper describes an application of intelligence- based predictive scheme to load-frequency control (LFC) in a two-area interconnected power system. In this investigation, at first, a dynamic model of the present system has to be considered and subsequently an efficient control scheme which is organized based on Takagi-Sugeno-Kang (TSK) fuzzy-based scheme and linear generalized predictive control (LGPC) scheme needs to be developed. In the control scheme proposed, frequency deviation versus load electrical power variation could efficiently be dealt with, at each instant of time. In conclusion, in order to validate the effectiveness of the proposed control scheme, the whole of outcomes are...