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    Distribution system planning considering integration of distributed generation and load curtailment options in a competitive electricity market

    , Article Electrical Engineering ; Volume 93, Issue 1 , 2011 , Pages 23-32 ; 09487921 (ISSN) Porkar, S ; Abbaspour Tehrani Fard, A ; Poure, P ; Saadate, S ; Sharif University of Technology
    Distribution systems management is becoming an increasingly complicated issue due to the introduction of new technologies, new energy trading strategies and new deregulated environment. In the new deregulated energy market and considering the incentives coming from the technical and economical fields, it is reasonable to consider distributed generation (DG) as a viable option to solve the lacking electric power supply problem. This paper presents a mathematical distribution system planning model considering three planning options to system expansion and to meet the load growth requirements with a reasonable price as well as the system power quality problems. DG is introduced as an attractive... 

    Improvement of Power Sharing In Microgrids Consist of Synchronous Generators and Converter Based Distributed Generation Units

    , M.Sc. Thesis Sharif University of Technology Zanganeh, Mohsen (Author) ; Mokhtari, Hossein (Supervisor)
    This dissertation studies the operation of the power sharing system in a micro-grid (MG) which includes a synchronous generator and the converter based distributed generation (DG) units. Increasing advent of MGs and the huge penetration of DGs to the existing power systems require comprehensive studies on the interactions between synchronous generators and converter based DGs for the sharing of power during and after the occurrence of different disturbances such as load changing. Thus, this project discusses existing control methods which can be used to share the power between a synchronous generator and converter based DGs. Then, a new control strategy is proposed in order to enhance the... 

    Optimal Distributed Generation Allocation and Sizing Considering Operation Indices

    , M.Sc. Thesis Sharif University of Technology Ghanbari, Niloofar (Author) ; Mokhtari, Hossein (Supervisor)
    The need for independent power generation has been increased in recent years with the growing demand in micro grid systems. Losses in power systems are unavoidable. These losses occur in transmission to distributionnetworks from the generation sites to the end-user loads. Reduction of power losses has been one of the reasons for engineers to be attracted by micro grid systems which include small size independent power generation units. However, in a micro grid with several DGs of different types and with all kinds of loads of variable nature, an optimal power balance in the system has to be achieved. This optimal objective, which results in minimal energy losses over a specific period of... 

    Planning and Optimization of an On-site Energy Service Network for a Rural Region

    , M.Sc. Thesis Sharif University of Technology Ahadi, Hassan (Author) ; Avami, Akram (Supervisor)
    Nowadays, classic energy supply systems are rapidly shifting towards more efficient, with less pollution, and more economic energy systems. In the meantime, the growing dependence of human activities on energy sources and the reduction of fossil fuels resources as the main source of energy supply at present time, has led to fundamental changes in the energy policy of communities. The use of distributed power generation systems utilizing renewable energy sources is one of the solutions that have been proposed in this regard. This research aims to develop a local energy supply network for a specific rural district using energy sources in place, so that the area is energy self-sufficient and... 

    Composite Distributed Generation and Transmission Expansion Planning Considering Uncertainties, Emission and Security

    , M.Sc. Thesis Sharif University of Technology Lotfi, Amir (Author) ; Hosseini, Hamid (Supervisor)
    During the recent past, due to the increase of electrical energy demand and governmental resources constraints in producing additional capacity in generation, transmission and distribution, privatization and restructuring in electrical industry has been considered. In most of the countries, different parts of electrical industry like generation, transmission and distribution have been separated in order to create competition. Considering these changes, environmental issues, energy growth, investment of private equity in energy generation units and difficulties of transmission lines expansion, DG units have been used in power systems. Moreover, reduction in need of transmission and... 

    Design a Comprehensive Framework for Distribution System Restoration in the Presence of Distributed Generations and Energy Storage Systems

    , Ph.D. Dissertation Sharif University of Technology Riahinia, Shahin (Author) ; Abbaspour Tehrani Fard, Ali (Supervisor) ; Moeini Aghtaie, Moein (Co-Supervisor)
    This thesis presents a stochastic framework to properly involve the uncertainties associated with demand in distribution system restoration (DSR) problem. The restoration process returns the system back to normal operation after any combination of system components have been lost due to an outage. During restoration, the system operator executes a set of actions that progressively mitigate the outage. These actions aim at minimizing the impact of the outage on the final user without compromising the security and operability of the system. In this framework, dynamic programming (DP) is used to solve DSR problem for a distribution system that accommodates various technologies of DG units and... 

    The Effect of Reconfiguration on the Operation of Smart Distribution Systems with Distributed Generations

    , Ph.D. Dissertation Sharif University of Technology Dorostkar Ghamsari, Mohammad Reza (Author) ; Fotuhi-Firuzabad, Mahmud (Supervisor)
    In this dissertation, the value of distribution network reconfiguration in presence of distributed generation is investigated. In the first step, a mathematical optimization model is devised to minimize daily network losses via applying hourly reconfigurations. The results show that the hourly reconfiguration reduces the losses. Then, sensitivity analyses on the renewable penetration, wind and load correlation, switching cost and wind power prediction are conducted and discussed. The switching cost analysis revealed that a great amount of loss reduction could be attained with a small number of switching operations. The worthiness of reconfiguration becomes more in systems with high... 

    Developing an Efficient Framework for Determining Distributed Locational Marginal Prices (DLMPs) in Active Distribution Systems Based on the Concept of Transactive Energy (TE)

    , M.Sc. Thesis Sharif University of Technology Pasban Gajan, Ali (Author) ; Moeini Aghtaei, Moein (Supervisor) ; Fotuhi-Firuzabad, Mahmud (Co-Supervisor)
    Nowdays, due to the growth of micro-grids, the development of dispersed production resources, and increased diversity in subscribers, energy management in modern distribution systems has encountered a lot of complexity. As a result, local electric power markets have attracted the attention of many researchers, due to the many technical and economic benefits. The purpose of these markets is to create competition between the participants and to increase the technical and economic efficiency of the distribution system. The most important challenges for these markets are to increase the technical and economic efficiency of the distribution network, maintain network reliability, protect the... 

    Integrated Control and Power Sharing of Distributed Generators in Islanded and Grid-Connected Microgrids

    , M.Sc. Thesis Sharif University of Technology Nokhbehzaeem, Javad (Author) ; Parniani, Mostafa (Supervisor)
    Distributed generation (DG) technologies have achieved an intense progress during the last years. One of the appropriate ways to enter a DG system in the electrical network is through the use of microgrids. Because the majority of DG units are connected to the grid with power electronic converters, specific control strategies have been developed for these converters. Control strategies of DGs in microgrid differ in the grid-connected and the islanded states of operation. Changing the control modes from one state to another requires a reliable islanding detection method, and results in unwanted transients. It is, therefore, desirable to devise an integrated control approach for both states.... 

    Using Machine Learning Methods to Determine Extreme Weather-Related Outage Scenarios for Optimal Siting and Sizing of Distributed Generation and Energy Storage Facilities to Enhance Distribution Network Resiliencey

    , M.Sc. Thesis Sharif University of Technology Mohammad Yari, Mohammad (Author) ; Hosseini, Hamid (Supervisor)
    Natural disasters such as storms, earthquakes, floods, etc. are among the factors that can damage the elements of the power grid and cause them to leave the grid. The result of these outages will be a widespread power outage, which will create many economic and social problems. Therefore, in recent years, the concept of resiliencey has been introduced in power system studies, which examines the extensive outputs in the network as a result of natural disasters.One way to improve the power system resiliency is to strengthen the network by upgrading existing equipment, installing new equipment, and modifying the operation of the network. Among these, the installation of distributed generation... 

    Distribution loss allocation for radial systems including dgs

    , Article IEEE Transactions on Power Delivery ; Vol. 29, issue. 1 , 2014 , pp. 72-80 ; ISSN: 08858977 Ghofrani-Jahromi, Z ; Mahmoodzadeh, Z ; Ehsan, M ; Sharif University of Technology
    Due to the liberalization of the electricity market and the introduction of distributed generation (DG), the importance of distribution loss allocation (LA) has increased. This paper presents a new method for distribution power LA in radial systems. The proposed method, which is based on the results of power flow and considers active and reactive power flows of lines for LA, is composed of three steps. In the first step, starting from the source nodes (i.e., the nodes whose generation is more than their load), the power loss allocated to all nodes is calculated and then the power loss allocated to the loads connected to each node is obtained. In the next step, the total power loss is... 

    Imperialist competition algorithm for distributed generation connections

    , Article IET Generation, Transmission and Distribution ; Volume 6, Issue 1 , January , 2012 , Pages 21-29 ; 17518687 (ISSN) Soroudi, A ; Ehsan, M ; Sharif University of Technology
    This study proposes an imperialist competition algorithm (ICA) to maximise the benefits of distribution network operators (DNOs) because of the existence of distributed generation (DG) units. The sum of active loss reduction and network investment deferral incentives has been considered as the objective function to be maximised in this study. The optimal location and size of DG units in the network are found considering various techno-economical issues. The application of the proposed methodology in the UK under current Ofgem financial incentives for DNOs is investigated. The ability of the proposed approach in finding the optimal solution is validated by comparing the obtained results with... 

    Stability analysis and experimental evaluation of a control strategy for islanded operation of distributed generation units

    , Article IEEJ Transactions on Industry Applications ; Volume 131, Issue 8 , 2011 , Pages 1013-1022 ; 09136339 (ISSN) Bahrani, B ; Karimi, H ; Iravani, R ; Sharif University of Technology
    This paper presents stability analysis of a distributed generation (DG) controller (1), in an islanded mode, based on the Mapping Theorem and the Zero Exclusion Condition, and validates the results based on a laboratory scale experimental setup. The DG unit is interfaced to the host system through a voltage-sourced converter (VSC). The control strategy regulates the load voltage at the desired value in the islanded mode, despite uncertainties in the load parameters. The frequency of the island is controlled in an open loop manner by an internal oscillator. The experimental results show that the controller provides robust voltage control for a wide range of load parameters, and even maintains... 

    Modeling, control and islanding detection of microgrids with passive loads

    , Article Proceedings of EPE-PEMC 2010 - 14th International Power Electronics and Motion Control Conference, 6 September 2010 through 8 September 2010 ; September , 2010 , Pages T11107-T11112 ; 9781424478545 (ISBN) Popov, M ; Karimi, H ; Nikkhajoei, H ; Terzija, V ; Sharif University of Technology
    This paper presents a control scheme for microgrids with passive loads. The existing control techniques for distributed generation systems are designed to operate either in the grid-connected or in the islanded mode. In the grid-connected mode of operation, a currentcontrolled scheme based on d-q variables is used for the regulation of real and reactive powers of the converter. In the islanded mode of operation, the converter is controlled in the voltage-controlled mode. This paper deals with the modeling of both control schemes. Furthermore, reconnection from the islanded mode to the grid-connected mode based on the use of adequate Phase-Locked Loops (PLLs) has been demonstrated  

    Stability analysis and experimental validation of a control strategy for autonomous operation of distributed generation units

    , Article 2010 International Power Electronics Conference - ECCE Asia -, IPEC 2010, 21 June 2010 through 24 June 2010 ; June , 2010 , Pages 464-471 ; 9781424453955 (ISBN) Bahrani, B ; Karimi, H ; Iravani, R ; IEEJ ; Sharif University of Technology
    This paper presents stability analysis of a distributed generation (DG) controller [1], in an islanded mode, based on the Mapping Theorem and the Zero Exclusion Condition, and validates the results based on a laboratory scale experimental setup. The DG unit is interfaced to the host system through a voltage-sourced converter (VSC). The control strategy regulates the load voltage at the desired value in the islanded mode, despite uncertainties in the load parameters. The frequency of the island is controlled in an open loop manner by an internal oscillator. The experimental results show that the controller provides robust voltage control for a wide range of load parameters, and even maintains... 

    Fixed-order decoupling of interval plant families

    , Article Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME ; Volume 139, Issue 1 , 2017 ; 00220434 (ISSN) Negim, M ; Nobakhti, A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2017
    A method for the reduction of interactions in linear time invariant (LTI) multivariable uncertain systems is proposed. An H∞-norm metric is proposed for the assessment of interactions in interval uncertain multiple-input multiple-output (MIMO) plants. Based on this, a procedure for the design of fixed-order dynamic decoupling precompensators for MIMO plants with interval uncertainty is outlined which can be solved using efficient solvers such as CVX. The proposed methodology is used to develop a low-order robust multivariable controller for voltage and frequency control of an islanded distributed generation (DG) unit. Copyright © 2017 by ASME  

    Resilience-based framework for switch placement problem in power distribution systems

    , Article IET Generation, Transmission and Distribution ; Volume 12, Issue 5 , March , 2018 , Pages 1223-1230 ; 17518687 (ISSN) Zare Bahramabadi, M ; Abbaspour, A ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
    Institution of Engineering and Technology  2018
    Optimal placement of switches can play a key role in providing resilience to power distribution systems against major faults caused by natural disasters. This study presents a resilience-based framework for optimal switch placement in distribution systems being consistent with the expansion plans of distributed generation units. At first, the impact of hurricanes on distribution system components is modelled using the geographic information system of distribution grid and the strength of components against extreme weather-related events. Then, a new resiliency index is proposed to assess the resilience of distribution grids. This index is involved in a mathematical model of the switch... 

    Power flow control of a matrix converter based micro-turbine distributed generation system

    , Article 2006 IEEE Power Engineering Society General Meeting, PES, Montreal, QC, 18 June 2006 through 22 June 2006 ; 2006 ; 1424404932 (ISBN); 9781424404933 (ISBN) Nikkhajoei, H ; Karimi Ghartemani, M ; Sharif University of Technology
    IEEE Computer Society  2006
    This paper presents a power flow controller for a matrix converter as the power electronic interface between a high-speed micro-turbine generator and a utility distribution system. The matrix converter converts the high-frequency of a micro-turbine generator to a conventional frequency of the utility system, based on a novel switching strategy. The controller regulates magnitude and phase-angle of the converter output voltage to accommodate real and reactive power flow requirements of the utility system. Performance of the matrix converter based microturbine generation system including the power flow controller is evaluated based on digital time-domain simulation studies in the PSCAD/EMTDC... 

    Optimal operation of distribution system with regard to distributed generation: A comparison of evolutionary methods

    , Article 2005 IEEE Industry Applications Conference, 40th IAS Annual Meeting, Kowloon, Hong Kong, 2 October 2005 through 6 October 2005 ; Volume 4 , 2005 , Pages 2690-2697 ; 01972618 (ISSN); 0780392086 (ISBN); 9780780392083 (ISBN) Niknam, T ; Ranjbar, A. M ; Shirani, A. R ; Mozafari, B ; Ostadi, A ; Sharif University of Technology
    This paper presents a new approach for optimal operation of distribution networks with regard to Distributed Generators (DGs). The objective function in this problem includes cost of active and reactive electrical energy generated by DGs, electrical energy markets and capacitors. Also, this paper presents both application and comparison of the metaheuristic techniques such as the Genetic Algorithm (GA), differential evolution, Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO), tabu search, to optimal operation of distribution networks. These methods are tested on two examples distribution network containing an IEEE 34 distribution test feeders and a practical distribution... 

    Optimal distributed generation allocation in distribution network using Hereford Ranch algorithm

    , Article ICEMS 2005: 8th International Conference on Electrical Machines and Systems, Nanjing, 27 September 2005 through 29 September 2005 ; Volume 2 , 2005 , Pages 916-918 ; 7506274078 (ISBN); 9787506274074 (ISBN) Gandomkar, M ; Vakilian, M ; Ehsan, M ; Sharif University of Technology
    IEEE Computer Society  2005
    The necessity for flexible electric systems, energy saving, loss reducing and environmental impact are providing Impetus to the development of Distributed Generation (DG). DG Includes the application of small generators, scattered throughout a power system, to provide the electric power needed by electrical customer. Such locally distributed generation, has several merits from the viewpoint of environmental restriction and location limitations, as well as transient and voltage stability In the power system. The exact solution of the DG allocation can be obtained by a complete enumeration of all feasible combinations of sites and sizes of DGs In the network. The number of alternatives could...