Search for: power-system-optimizations
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    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) Rahmani, M ; Sadati, N ; Sharif University of Technology
    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,... 

    Optimal reactive power dispatch for improving voltage stability margin using a local voltage stability index

    , Article Energy Conversion and Management ; Volume 59 , 2012 , Pages 66-73 ; 01968904 (ISSN) Rabiee, A ; Vanouni, M ; Parniani, M ; Sharif University of Technology
    Management of reactive power resources is vital for stable and secure operation of power systems in the view point of voltage stability. This paper deals with the management of on-load tap changers (OLTCs) and dynamic VAR sources (including synchronous generators, synchronous condensers, and shunt reactive power compensators) to improve voltage stability margin (VSM) of power systems. This problem is usually called optimal reactive power dispatch (ORD) in the literature. The main contribution of the paper is to introduce a new objective function for the ORD problem. The proposed objective function is derived based on a local voltage stability index, called DSY, and has a strong correlation... 

    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) Rahmani, M ; Sadati, N ; Sharif University of Technology
    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... 

    Standing phase angle reduction based on a wide area monitoring system using genetic algorithm

    , Article International Journal of Emerging Electric Power Systems ; Volume 11, Issue 3 , Jul , 2010 ; 1553779X (ISSN) Nourizadeh, S ; Ranjbar, A. M ; Pishvaie, M. R ; Sadeghi, M ; Sharif University of Technology
    During power system restoration, it is necessary to check the phase angle between two buses before closing circuit breakers to connect a line between them. A novel approach for reducing large standing phase angle (SPA) based on Genetic Algorithm (GA) is presented in this paper. The proposed approach starts with a state estimation on Wide Area Monitoring System (WAMS) data measurements and considering power system operation and angular stability constraints, seeks an optimal control action scenario for reducing SPA. Since these constraints are evaluated based on WAMS data, the presented approach is considerably high speed and accurate. As an optimization problem, objective function of the... 

    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) Khorsandi, A ; Hosseinian, S. H ; Ghazanfari, A ; Sharif University of Technology
    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... 

    Electrical power system resilience assessment: a comprehensive approach

    , Article IEEE Systems Journal ; Volume 14, Issue 2 , 2020 , Pages 2643-2652 Sabouhi, H ; Doroudi, A ; Fotuhi Firuzabad, M ; Bashiri, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Extreme weather events such as earthquake and hurricane have disastrous consequences on power systems. Due to the inherent nature of these events, as high-impact low-probability (HILP) events, selection of an appropriate method that can provide the effects of weather conditions on the power system behavior still remains a significant challenge. Resilience is a new concept that focuses on mitigating the destructive effects of such disastrous events on power systems. This article provides a fundamental framework for quantifying and modeling of power systems resilience, with focus on high wind incidence. The algorithm composes of four steps. In the first step, the prerequisites of the analysis... 

    Multi objective distributed generation planning using NSGA-II

    , Article 2008 13th International Power Electronics and Motion Control Conference, EPE-PEMC 2008, Poznan, 1 September 2008 through 3 September 2008 ; 2008 , Pages 1847-1851 ; 9781424417421 (ISBN) Ahmadi, M ; Yousefi, A ; Soroudi, A ; Ehsan, M ; Sharif University of Technology
    With the increasing share of distributed generation in electrical energy supply, the proper planning procedure for using these units, has become more vital for power system planners. In this paper, the application of multi-objective optimization techniques for siting, sizing and determination of the proper technology to be used, has been investigated in such a way that, the load demand during the planning horizon is met and the technical and environmental constraints are satisfied. Unlike the traditional optimization methods used in power system optimization, NSGA-II multi-objective optimization algorithm does not consider techno-economical and environmental parameters in the constraints of...