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distributed-generation
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A bi-level approach for optimal contract pricing of independent dispatchable DG units in distribution networks
, Article International Transactions on Electrical Energy Systems ; Volume 26, Issue 8 , 2016 , Pages 1685-1704 ; 20507038 (ISSN) ; Rajabi Ghahnavieh, A ; Haghighat, H ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
Distributed generation (DG) units are increasingly installed in the power systems. Distribution companies (DisCo) can opt to purchase the electricity from DG in an energy purchase contract to supply the customer demand and reduce energy loss. This paper proposes a framework for optimal contract pricing of independent dispatchable DG units considering competition among them. While DG units tend to increase their profit from the energy purchase contract, DisCo minimizes the demand supply cost. Multi-leader follower game theory concept is used to analyze the situation in which competing DG units offer the energy price to DisCo and DisCo determines the DG generation. A bi-level approach is used...
A combination of genetic algorithm and simulated annealing for optimal DG allocation in distribution networks
, Article Canadian Conference on Electrical and Computer Engineering 2005, Saskatoon, SK, 1 May 2005 through 4 May 2005 ; Volume 2005 , 2005 , Pages 645-648 ; 08407789 (ISSN) ; Vakilian, M ; Ehsan, M ; Sharif University of Technology
2005
Abstract
This paper presents a new algorithm based on integrating the use of genetic algorithms and simulated annealing methods to optimal allocation of distributed generation resources in distribution networks. Through this algorithm a significant improvement in the optimization goal is achieved. With a numerical example the superiority of the proposed algorithm is demonstrated in comparison with the simple genetic algorithm. © 2005 IEEE
A combination of MADM and genetic algorithm for optimal DG allocation in power systems
, Article 42nd International Universities Power Engineering Conference, UPEC 2007, Brighton, 4 September 2007 through 6 September 2007 ; 2007 , Pages 1031-1035 ; 1905593368 (ISBN); 9781905593361 (ISBN) ; Afsharnia, S ; Khodayar, M. E ; Rahimikian, A ; Sharbafi, M. A ; Sharif University of Technology
2007
Abstract
Distributed Generation (DG) can help in reducing the cost of electricity to the customer, relieve network congestion, provide environmentally friendly energy close to load centers as well as promote system technical characteristics such as loss reduction, voltage profile enhancement, reserve mitigation and many other factors. Furthermore, its capacity is also scalable and it can provide voltage support at distribution level. The planning studies include penetration level and placement evaluation which are influenced directly by DG type. Most of the previous publications in this field chose one or two preferred parameter as basic objective and implement the optimizations in systems. But due...
A comprehensive digital protection scheme for low-voltage microgrids with inverter-based and conventional distributed generations
, Article IEEE Transactions on Power Delivery ; Volume 32, Issue 1 , 2017 , Pages 441-452 ; 08858977 (ISSN) ; Parniani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
Microgrid (MG) protection is one of the main challenges in proliferation of microgrids. Due to limited fault current feeding of inverter-based distributed generations (DGs), in islanded operation of MG, protection problems become more complicated; and, therefore, conventional protection strategies cannot be applied. Hence, new protection methods that are applicable in islanded and grid-connected modes of operation are necessary. In this paper, a comprehensive digital-relay based protection is introduced for the protection of MGs. The proposed method includes protection of lines, distributed generations, and the point of common coupling. The structure and graphical schematic of the proposed...
Active power management of multihybrid fuel cell/supercapacitor power conversion system in a medium voltage microgrid
, Article IEEE Transactions on Smart Grid ; Volume 3, Issue 4 , 2012 , Pages 1903-1910 ; 19493053 (ISSN) ; Hamzeh, M ; Mokhtari, H ; Karimi, H ; Sharif University of Technology
2012
Abstract
This paper proposes a hierarchical active power management strategy for a medium voltage (MV) islanded microgrid including a multihybrid power conversion system (MHPCS). To guarantee excellent power management, a modular power conversion system is realized by parallel connection of small MHPCS units. The hybrid system includes fuel cells (FC) as main and supercapacitors (SC) as complementary power sources. The SC energy storage compensates the slow transient response of the FC stack and supports the FC to meet the grid power demand. The proposed control strategy of the MHPCS comprises three control loops; dc-link voltage controller, power management controller, and load current sharing...
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...
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...
A distribution network expansion planning model considering distributed generation options and techo-economical issues
, Article Energy ; Volume 35, Issue 8 , 2010 , Pages 3364-3374 ; 03605442 (ISSN) ; Ehsan, M ; Sharif University of Technology
Abstract
This paper presents a dynamic multi-objective model for distribution network expansion, considering the distributed generations as non-wire solutions. The proposed model simultaneously optimizes two objectives namely, total costs and technical constraint satisfaction by finding the optimal schemes of sizing, placement and specially the dynamics (i.e., timing) of investments on DG units and/or network reinforcements over the planning period. An efficient heuristic search method is proposed to find non-dominated solutions of the formulated problem and a fuzzy satisfying method is used to choose the final solution. The effectiveness of the proposed model and search method are assessed and...
A dynamic fuzzy interactive approach for DG expansion planning
, Article International Journal of Electrical Power and Energy Systems ; Volume 43, Issue 1 , 2012 , Pages 1094-1105 ; 01420615 (ISSN) ; Ehsan, M ; Fattahi Meyabadi, A ; Sharif University of Technology
2012
Abstract
This paper presents a dynamic multi objective model for distribution network expansion, considering the distributed generators (DGs) and network reinforcements. The proposed model simultaneously optimizes three objective functions namely, total cost, emission cost and technical satisfaction (voltage profile) by finding the optimal schemes of timing, sizing, placement and DG technologies in a long term planning period (dynamic planning). The importance of each objective function can be changed in the interactive steps. The calculation algorithm is based on Chaotic Local Search with Modified Honey Bee Mating Optimization (CLSMHBMO). The effectiveness of the proposed model and the calculation...
A fast and cost-effective control of a three-phase stand-alone inverter
, Article 8th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2017, 14 February 2017 through 16 February 2017 ; 2017 , Pages 67-72 ; 9781509057665 (ISBN) ; Keikha, O ; Yaghoubi, M ; Tahami, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
This paper proposes a straightforward control method for voltage control of a three-phase transformer-based inverter in uninterruptible power supplies or distributed generation systems. The approach offers a dual-loop design consisting inner current control loop and outer voltage loop. Sliding mode current controller provides desired bandwidth for voltage controller which consists of a state feedback term for stabilization and resonant term for harmonic damping. The proposed scheme provides fast dynamic response and low total harmonic distortion even for high power inverters with the limitations of switching frequency and LC filter components. Experimental studies for 2KVA linear and...
A flexibility-oriented model for distribution system expansion planning studies
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 737-741 ; 9781728115085 (ISBN) ; Jooshaki, M ; Moeini Aghtaei, M ; Abbaspour, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Employing more flexibility in power systems is one of the main challenges brought about by integrating more renewable energy sources in power systems. A promising way to overcome this challenge is to have local sources of flexibility in distribution level. In this respect, a novel approach is introduced in this paper for multi-stage distribution system expansion planning which jointly considers expansion of the network assets as well as flexibility enhancement. To this end, construction and reinforcement of feeders and substations are considered as various alternatives for network expansion. Moreover, installation of conventional dispatchable distributed generation units is selected as the...
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...
A heuristic trade off model for integration of distributed generations in deregulated power systems considering technical, economical and environmental issues
, Article 2008 IEEE 2nd International Power and Energy Conference, PECon 2008, Johor Baharu, 1 December 2008 through 3 December 2008 ; 2008 , Pages 1275-1279 ; 9781424424054 (ISBN) ; Nasiri, R ; Bagheri, M ; Tehrani, A. A ; Sharif University of Technology
2008
Abstract
With the introduction of restructuring concepts to traditional power systems, a great deal of attention is given to the utilization of distributed generation. Since the integration of DG units has been known as an alternative for main grid as a resource for energy supply, the determination of optimal sizing and sitting is an important issue in the planning procedure of DG. This work presents a comprehensive multi-objective model for integration of distributed generations into a distribution network, regarding various technical, economical and environmental issues such as reduction of carbon dioxide emissions and investment & running costs while the bus voltages shall be kept within...
A high performance real-time simulator for controllers hardware-in-the-loop testing
, Article Energies ; Volume 5, Issue 6 , 2012 , Pages 1713-1733 ; 19961073 (ISSN) ; Karimi, H ; Etemadi, A ; Iravani, R ; Sharif University of Technology
2012
Abstract
This paper presents a high performance real-time simulator for power electronic systems applications and primarily intended for controller hardware-in-the-loop (CHIL) testing. The novelty of the proposed simulator resides in the massively parallel hardware architecture that efficiently exploits fine-grained parallelism without imposing severe communication overhead time that can limit the performance. The simulator enables the use of a nanosecond range simulation timestep to simulate power electronic systems. Through the use of this nanosecond range simulation timestep, the simulator minimizes the error arising from the intersimulation timestep switching phenomenon associated with CHIL. The...
A model for stochastic planning of distribution network and autonomous DG units
, Article IEEE Transactions on Industrial Informatics ; Volume 16, Issue 6 , August , 2020 , Pages 3685-3696 ; Farzin, H ; Abbaspour, A ; Fotuhi-Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
IEEE Computer Society
2020
Abstract
This article presents a mixed-integer linear stochastic model for the optimal expansion planning of electricity distribution networks and distributed generation (DG) units. In the proposed framework, autonomous DG units are aggregated and modeled using the well-known energy hub concept. In this model, the uncertainties of heat and electricity demand as well as renewable generation are represented using various scenarios. Although this is a standard technique to capture the uncertainties, it drastically increases the dimensions of this optimization problem and makes it practically intractable. In order to address this issue, a novel iterative method is developed in this article to enhance the...
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...
A multi-objective framework for energy resource scheduling in active distribution networks
, Article International Journal of Ambient Energy ; 2018 , Pages 1-13 ; 01430750 (ISSN) ; Ghazi, R ; Moeini Aghtaie, M ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
Purpose: The purpose of this paper is to investigate the impacts of electric vehicles' (EVs) charging/discharging decisions in energy resources scheduling problem of active distribution networks. Design/methodology/approach: The problem under study is modelled as a two-stage optimisation problem in which the main requirements of EV owners are introduced as an objective function of the first stage. The total energy costs and the emission factor are considered as the main criteria of the second stage. The output generation schedules of distributed generation (DG) technologies together with the charging/discharging schedule of EVs are proposed as decision variables of the energy scheduling...
A multi-objective framework for energy resource scheduling in active distribution networks
, Article International Journal of Ambient Energy ; Volume 40, Issue 5 , 2019 , Pages 504-516 ; 01430750 (ISSN) ; Ghazi, R ; Moeini Aghtaie, M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Purpose: The purpose of this paper is to investigate the impacts of electric vehicles' (EVs) charging/discharging decisions in energy resources scheduling problem of active distribution networks. Design/methodology/approach: The problem under study is modelled as a two-stage optimisation problem in which the main requirements of EV owners are introduced as an objective function of the first stage. The total energy costs and the emission factor are considered as the main criteria of the second stage. The output generation schedules of distributed generation (DG) technologies together with the charging/discharging schedule of EVs are proposed as decision variables of the energy scheduling...
A multistage model for distribution expansion planning with distributed generation in a deregulated electricity market
, Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 34, Issue 3 , 2010 , Pages 275-287 ; 10286284 (ISSN) ; Abbaspour Tehrani Fard, A ; Poure, P ; Saadate, S ; Sharif University of Technology
2010
Abstract
Distribution systems management is becoming an increasingly complicated issue due to the introduction of new technologies, new energy trading strategies and a new deregulated environment. In the new deregulated energy market and considering the incentives coming from the technical and economic fields, it is reasonable to consider Distributed Generation (DG) as a viable option for systems reinforcement in competition with voltage regulator devices, to solve the lacking electric power supply problem and meet the load growth requirements with a reasonable price as well as the system power quality problems. The problem of optimal placement and size is formulated in two stages; minimization of...
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...