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distributed-generation
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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) ; Vakilian, M ; Ehsan, M ; Sharif University of Technology
IEEE Computer Society
2005
Abstract
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...
Optimal DG sizing in primary distribution feeders using dynamic programming approach
, Article 2012 11th International Conference on Environment and Electrical Engineering, EEEIC 2012 - Conference Proceedings, 18 May 2012 through 25 May 2012, Venice ; 2012 , Pages 371-375 ; 9781457718281 (ISBN) ; Kenari, M. T ; Mehrasa, M ; Sharif University of Technology
IEEE
2012
Abstract
Distributed generation (DG) corresponds to the application of small generating units which are the set up in distribution systems or near load centers. Utilization of DG influences various operational indices of the distribution feeders such as feeder loading, electrical losses and voltage profile. In addition, use of DG in its appropriate size is an essential tool to attain the DG maximum potential advantages. In this paper, an optimization method is proposed to determine the optimal size of DG in the distribution system. This method considers the system technical factors such as losses, voltage profile and loading of the primary distribution system feeders. The optimization process is...
IoT-based intelligent source–load–storage coordination scheme for prosumer campus microgrids
, Article Frontiers in Energy Research ; Volume 10 , 2022 ; 2296598X (ISSN) ; Shahzad, M ; Shehzad, M ; Akhter, J ; Almohaimeed, Z. M ; Akram, R ; Hussain, M. M ; Sharif University of Technology
Frontiers Media S.A
2022
Abstract
Electrical energy is very necessary for human life in the modern era. The rising energy prices, depletion of fossil fuels, and instability of the grid are alarming situations. So, it needs a smart solution to ensure the balance between pricing and saving natural resources. Some other issues like environmental change, limitations on installation of new transmission lines, reliability concerns, and considering the expansion in distributed energy generation technologies promise the implementation of distributed generation extensively. The integration of two or more energy supplies in a power system is known as distributed energy resource system. In this study, a university campus is taken as a...
Automatic image annotation using semi-supervised generative modeling
, Article Pattern Recognition ; Volume 48, Issue 1 , January , 2015 , Pages 174-188 ; 00313203 (ISSN) ; Jamzad, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Image annotation approaches need an annotated dataset to learn a model for the relation between images and words. Unfortunately, preparing a labeled dataset is highly time consuming and expensive. In this work, we describe the development of an annotation system in semi-supervised learning framework which by incorporating unlabeled images into training phase reduces the system demand to labeled images. Our approach constructs a generative model for each semantic class in two main steps. First, based on Gamma distribution, a generative model is constructed for each semantic class using labeled images in that class. The second step incorporates the unlabeled images by using a modified EM...
Micro-grid stabilizer design using sliding mode controller
, Article International Journal of Electrical Power and Energy Systems ; Volume 116 , March , 2020 ; Parvari, R ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Future of the network stability is endangered by increasing the number of Distributed Generation (DG) and Renewable Energy Source (RES) units. The idea of the Virtual Synchronous Machine (VSM) has been raised to control the power electronic-based DG/RES converters in order to have better integration with the grid. This paper introduces a new stabilizer design for VSM-based converters to guarantee the stability of the micro-grid (MG). In this regard, the Sliding Mode Control (SMC) theory, which is robust against the disturbances and uncertainties, is employed to cope with the intermittent and nonlinear nature of DGs. The mutual operation of the proposed inverter and MG stabilizer has the...
Incorporating flexibility requirements into distribution system expansion planning studies based on regulatory policies
, Article International Journal of Electrical Power and Energy Systems ; Volume 118 , 2020 ; Jooshaki, M ; Moeini Aghtaie, M ; Abbaspour, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Increasing penetration of renewable energy sources with intermittent generation calls for further flexibility requirements for efficient as well as the safe operation of power systems. Considering the significant growth of distributed energy resources in distribution systems, a promising approach to fulfill such requirements is to deploy local flexibility sources at the distribution level. Nonetheless, due to the monopoly nature of electricity distribution business, effective regulations are required to direct distribution companies toward fulfilling such goals. Accordingly, this paper aims at proposing various policies to motivate distribution companies to enhance the flexibility of their...
Reliability assessment of distribution system with the integration of photovoltaic and energy storage systems
, Article Sustainable Energy, Grids and Networks ; Volume 28 , 2021 ; 23524677 (ISSN) ; Esmaeili Nezhad, A ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
With the current focus on energy and the environment, efficient integration of renewable energies, especially solar energy into power systems, is becoming indispensable. Moreover, to fully capture solar potentials and to recognize the unique characteristics associated with solar energy in power systems reliability assessment, a profound investigation is needed. Accordingly, this paper attempts to establish a comprehensive analytical approach for modeling the reliability of a hybrid system (Photovoltaic (PV) system with Energy Storage System (ESS)). To this end, the output of the PV system is modeled by a multi-state model, and the ESS system is modeled as a two-state Markov model. Moreover,...
On the explicit formulation of reliability assessment of distribution systems with unknown network topology: Incorporation of DG, switching interruptions, and customer-interruption quantification
, Article Applied Energy ; Volume 324 , 2022 ; 03062619 (ISSN) ; Lehtonen, M ; Fotuhi Firuzabad, M ; Muñoz Delgado, G ; Contreras, J ; Arroyo, J. M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper presents an original approach for the evaluation of reliability of active distribution networks with unknown topology. Built upon novel reformulations of conventional definitions for distribution reliability indices, the dependence of system-oriented reliability metrics on network topology is explicitly formulated using a set of mixed-integer linear expressions. Unlike previously reported works also modeling mathematically the relationship between reliability assessment and network topology, the proposed approach allows considering the impact of distributed generation (DG) while accounting for switching interruptions. Moreover, for the first time in the emerging closely related...
A multi-objective framework for distributed energy resources planning and storage management
, Article Applied Energy ; Volume 314 , 2022 ; 03062619 (ISSN) ; Ceylan, O ; Ozdemir, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The use of energy storage systems (ESS) and distributed generators (DGs) to improve reliability is one of the solutions that has received much attention from researchers today. In this study, we utilize a multi-objective optimization method for optimal planning of distributed generators in electric distribution networks from the perspective of multi-objective optimization. The objective is to improve the reliability of the network while reducing the annual cost and network losses. A modified version of the multi-objective sine–cosine algorithm is used to determine the optimal size, location, and type of DGs and the optimal capacity, location, and operation strategy of the ESS. Three case...
Energy management of Plug-In Hybrid Electric Vehicles in renewable-based energy hubs
, Article Sustainable Energy, Grids and Networks ; Volume 32 , 2022 ; 23524677 (ISSN) ; Dehghanian, P ; Davoudi, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Proliferation of Plug-in Hybrid Electric Vehicles (PHEVs) and integration of various distributed generation (DG) technologies have been recognized to play an undeniable role in modern power systems of the future. In order to effectively model the interactions of these two technologies, this paper develops a multi-criteria framework to coordinate the charging behaviors of PHEVs within an energy hub platform. In this regard, the desirable charging profiles from the viewpoint of both PHEV owners and hub manager are first captured and reported to the PHEVs Coordinator Entity (PCE). The PCE, then, runs an optimization framework in which several criteria including the PHEV owners’ convenience,...
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) ; Nobakhti, A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2017
Abstract
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
Distribution loss allocation for radial systems including dgs
, Article IEEE Transactions on Power Delivery ; Vol. 29, issue. 1 , 2014 , pp. 72-80 ; ISSN: 08858977 ; Mahmoodzadeh, Z ; Ehsan, M ; Sharif University of Technology
Abstract
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...
A new power management control strategy for a MV microgrid with both synchronous generator and inverter-interfaced distributed energy resources
, Article IEEE International Symposium on Industrial Electronics ; 1- 4 June , 2014 , pp. 2529-2534 ; ISBN: 978-147992399-1 ; Hamzeh, M ; Mokhtari, H ; Karimi, H ; Sharif University of Technology
Abstract
Control strategies of a microgrid which includes both synchronous generators and converter-based distribution generation (DG) units must be designed such that effective operation of the microgrid is achieved. The main objective of this paper is to develop a high performance control strategy for an islanded medium voltage (MV) microgrid consisting of inverter and non-inverter interfaced DG units. A new control method for the synchronous generator in an islanded microgrid is proposed based on a virtual droop scheme. The proposed strategy can effectively manage the real and reactive powers of the microgrid among the inverter and non-inverter based DG units. The steady state and dynamic...
A decentralized control method for a low-voltage dc microgrid
, Article IEEE Transactions on Energy Conversion ; Vol. 29, issue. 4 , Dec , 2014 , p. 793-801 ; 08858969 ; Ashourloo, M ; Mokhtari, H ; Sharif University of Technology
Abstract
DC microgrids (DC-MGs) are becoming popular as an effective means to integrate various renewable energy resources. Conventionally, the droop control is adopted as a decentralized control strategy for proper power sharing without using any communication link. However, the conventional droop control often deteriorates due to the effects of unequal line resistances. In this paper, a control strategy is proposed for a DC-MG to achieve perfect power sharing considering the effects of line resistances. The DC-MG under study consists of a photovoltaic system, two energy storage systems, a grid-connected converter system, and dc loads. The control strategy of the converters is addressed under...
Control of a microgrid with unbalanced loads using virtual negative-sequence impedance loop
, Article PEDSTC 2014 - 5th Annual International Power Electronics, Drive Systems and Technologies Conference ; 2014 , p. 78-83 ; Karimi, H ; Mokhtari, H ; Mahseredjian, J ; Sharif University of Technology
Abstract
This paper presents an effective control strategy for autonomous operation of a multi-bus medium voltage (MV) microgrid (MG) consisting of several dispatchable distributed generation (DG) units. Each electronically-coupled DG unit supplies the loads which can be unbalanced due to the inclusion of single-phase loads. The proportional resonance (PR) and droop controllers are, respectively, used to regulate the load voltage and share the average powers among the DG units. The virtual negative-sequence impedance controller (VNSIC) is proposed to effectively compensate the negative-sequence currents of the unbalanced loads. Moreover, the VNSIC minimizes the negative-sequence currents in the MV...
An adaptive droop control method for low voltage DC microgrids
, Article PEDSTC 2014 - 5th Annual International Power Electronics, Drive Systems and Technologies Conference ; December , 2014 , p. 84-89 ; Ashourloo, M ; Mokhtari, H ; Sharif University of technology
Abstract
DC microgrids (MGs) are becoming popular as effective means to integrate different energy resources. Conventionally, the droop control is adopted as a decentralized control method for power sharing in DC MGs. However, current sharing accuracy or voltage regulation deteriorates due to the effects of line impedances. In this paper, a new adaptive control strategy is proposed for DC MGs. In low load conditions, the output currents of the DGs are far from their maximum acceptable limits. Therefore, current sharing accuracy is not important. As load increases, the output currents of the DGs approach their maximum acceptable limits. Therefore, at high load conditions, accurate current sharing is...
A game theoretic framework for DG optimal contract pricing
, Article 2013 4th IEEE/PES Innovative Smart Grid Technologies Europe, ISGT Europe 2013 ; 2013 ; 9781479929849 (ISBN) ; Rajabi-Ghahnavieh, A ; Zahedian, A ; Sharif University of Technology
2013
Abstract
This paper presents a new approach based on multi leader follower game in order to find the optimal contract price of distributed generation in distribution network considering competition among them. The leader problems correspond to the independent DG units who decide to maximize the individual profits, while the follower problem refers to the distribution company (DisCo) which seeks the minimization of the payments incurred in attending the expected demand while satisfying network constraints. Disco can purchase energy either from the transmission network through the substations or from the DG units within its network. The DisCo minimization problem acts as a constraint into the each DG...
U-shaped energy loss curves utilization for distributed generation optimization in distribution networks
, Article Journal of Zhejiang University: Science C ; Volume 14, Issue 11 , 2013 , Pages 887-898 ; 18691951 (ISSN) ; Ehsan, M ; Nouri, H ; Sharif University of Technology
2013
Abstract
We propose novel techniques to find the optimal location, size, and power factor of distributed generation (DG) to achieve the maximum loss reduction for distribution networks. Determining the optimal DG location and size is achieved simultaneously using the energy loss curves technique for a pre-selected power factor that gives the best DG operation. Based on the network's total load demand, four DG sizes are selected. They are used to form energy loss curves for each bus and then for determining the optimal DG options. The study shows that by defining the energy loss minimization as the objective function, the time-varying load demand significantly affects the sizing of DG resources in...
A stochastic framework for short-term operation of a distribution company
, Article IEEE Transactions on Power Systems ; Volume 28, Issue 4 , 2013 , Pages 4712-4721 ; 08858950 (ISSN) ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
2013
Abstract
This paper presents a stochastic framework for short-term operation of a distribution company (disco). The proposed framework optimizes disco's operational decisions in two hierarchical stages. The first stage, called day-ahead operation stage (DAOS), deals with the operational decisions on purchases from the day-ahead market and commitment of distributed generation (DG) units. The objective of this stage is to minimize the expected operating cost while the financial risk exposed by uncertain real-time prices and loads is restricted to a given level. The model associated with this stage is based on the mixed-integer programming (MIP) format. The second stage, named real-time operation stage...
A decentralized self-adjusting control strategy for reactive power management in an islanded multi-bus MV microgrid
, Article Canadian Journal of Electrical and Computer Engineering ; Volume 36, Issue 1 , 2013 , Pages 18-25 ; 08408688 (ISSN) ; Mokhtari, H ; Karimi, H ; Sharif University of Technology
2013
Abstract
This paper presents a decentralized self-adjusting reactive power controller for the autonomous operation of a multi-bus medium voltage (MV) microgrid. The main objective of the proposed control strategy of each distributed generation (DG) unit is to compensate the reactive power of its local loads and to share the reactive power of the nonlocal loads among itself and other DG units. The proposed control strategy includes an improved droop controller whose parameters are adjusted according to the reactive power of the local loads. A virtual inductive impedance loop is augmented to the voltage controller to enhance the steady state and transient responses of the proposed reactive power...