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distributed-generation
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Provision of A Framework for Distribution System Expansion Planning Considering Flexibility Requirements for Massive Integration of Renewable Sources
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehrani Fard, Ali (Supervisor)
Abstract
One of the challenges which increasing penetration of renewable energy sources with variable generation brings is the need for more flexibility in the power system. A promising way to overcome the challenge is to have local sources of the flexibility in distribution level. To this end, we present a new model for multi-stage distribution system expansion planning which jointly considers expanding the network assets and increasing the flexibility at local level by installing conventional dispatchable distributed generator units and energy storage systems. Demand response is also considered as another source of the flexibility which can be utilized by the system operator. Since deviating from...
Robust Hierarchical Control of AC Microgrids
, Ph.D. Dissertation Sharif University of Technology ; Sadati, Naser (Supervisor) ; Hamzeh, Mohsen (Supervisor)
Abstract
New nonlinear voltage and current control strategies based on backstepping control and a high-order sliding mode differentiator for microgrid are proposed. The microgrid consists of multiple distributed generation (DG) units with an arbitrary configuration that can be parametrically uncertain or topologically unknown. The proposed method robustly regulates the microgrid voltages and currents in the presence of parametric uncertainties, unmodeled dynamics, load imbalances, and nonlinear loads with harmonic/interharmonic currents. In contrast to existing methods, the proposed method does not need to know the frequency of harmonic and interharmonic current of microgrid loads that lead to the...
Power Flow Control and Power Quality Enhancement in Grid-Connected Microgrid with Back-to-Back Converter
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
A microgrid system consists of some distributed generators (DGs) and local loads which can operate in both grid-connected and islanded modes of operation. An islanded mode of operation is required when the grid voltage deteriorates and its power quality drops. This islanding operation can be attained by opening grid-side switches or by using back-to-back (b-to-b) converters. Due to the increase of highly sensitive loads and to have better power control and higher power quality, the use of back-to-back converters has recently attracted interests among researchers. However, the major drawback of this solution is the cost of a b-to-b converter. Therefore the aim of this project is to gain some...
An Improved Voltage and Frequency Droop Control Method for Microgrids having Inverter Based Resources, Realizing the Effect of Lines R/X
, M.Sc. Thesis Sharif University of Technology ; Vakilian, Mehdi (Supervisor)
Abstract
The centralized and decentralized control approaches are the most effective control approaches to be applied in micro grids. However, practically to rerduce the cost and improve the reliability, decentralized control is usually employed. Initially, this thesis discusses the components and dynamic model of the micro grid in order to evaluate the stability. Then, it introduces the decentralized control methods which can be used in a micro grid. In the next step, a sample micro gird is studied (with high ratio of lines R/X). This microgrid has three DG plants having DC voltage sources, inverter, and LCL filter. The performance of AVR controls is evaluated by combining the PQ and droop control...
Study and Improvement of Stability of Generator-based Distributed Generation units Inpresence of Large Nonlinear Loads
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
Hyderogels are hydrophilic polymers with three dimensional network structure, due to their high water absoption, their application to life and industry is increasing from day to day, such as tissue engineering, actuators and sensors, drug delivery and therapeutic treatment. In this project, it has been attempted to produce polyacrylamide/alginate double network hydrogels with the use of graphene oxide nanosheets to indicate that it is possible to combine toughness and self-healing in a hydrogel with the opposite nature of each other. To evaluate mechanical properties, uniaxial tensile test and loading-unloading test were used. The results indicate that increase the weight ratio of acrylamide...
Electricity Distribution System Planning Considering Incentive Reliability Regulations
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour Tehranifard, Ali (Supervisor) ; Lehtonen, Matti (Co-Supervisor) ; Fotuhi Firuzabad, Mahmoud (Co-Supervisor)
Abstract
Electricity distribution systems are dynamically expanded in anticipation of new demands. Cost and reliability are the most important factors in finding the optimal plans for network expansion. Recently, implementation of incentive reliability regulations has accentuated the role of reliability considerations in distribution systems studies. This is because such incentive schemes create a direct link between distribution companies' revenues and their service reliability. Thus, these schemes have changed the role of reliability from a technical constraint to an economic factor. In this occasion, distribution companies require new techniques to incorporate the effects of incentive reliability...
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 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...
Neuro-fuzzy islanding detection in distributed generation
, Article 2012 IEEE Innovative Smart Grid Technologies - Asia, ISGT Asia 2012, 21 May 2012 through 24 May 2012 ; May , 2012 ; 9781467312219 (ISBN) ; Sheikholeslamzadeh, M ; Ranjbar, A. M ; Mozafari, B ; Sharif University of Technology
2012
Abstract
Islanding detection methods are divided into three main groups as remote, active and passive. Although passive schemes have larger Non Detection Zones (NDZ) relative to other schemes, they are more used in utilities due to their low costs and less PQ problems than other schemes. Passive Schemes are based on the measurements of passive system parameters. These parameters are measured at the point of common coupling (PCC). A new approach in passive techniques is the use of data-mining to classify the system parameters. In this paper, massive indices are collected by simulation of a practical distribution system in PSCAD/EMTP environment. These indices include voltage, frequency, current,...
A novel SVM approach of islanding detection in micro grid
, Article 2012 IEEE Innovative Smart Grid Technologies - Asia, ISGT Asia 2012, 21 May 2012 through 24 May 2012 ; May , 2012 ; 9781467312219 (ISBN) ; Sheikholeslamzadeh, M ; Ranjbar, A. M ; Mozafari, B ; Sharif University of Technology
2012
Abstract
Passive islanding detection schemes are more used in utilities due to their low costs and less harmonic problems although having larger Non Detection Zones (NDZ) relative to other schemes. Passive system measurements at the point of common coupling (PCC) are the basis of this scheme. A new approach in passive techniques is the use of intelligent based methods in data-mining to classify the system parameters which affect the islanding detection. As a result, by finding an efficient and robust data-mining algorithm, the passive schemes problem, which is their relatively large NDZ, will be minimized. In this paper, massive measurements are collected by simulation of IEEE standard distribution...
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...
μ-Synthesis control for an islanded microgrid with structured uncertainties
, Article IECON Proceedings (Industrial Electronics Conference), 7 November 2011 through 10 November 2011 ; November , 2011 , Pages 3064-3069 ; 9781612849720 (ISBN) ; Karimi, H ; Sharif University of Technology
2011
Abstract
This paper presents a robust control scheme for an islanded microgrid in the presence of structured uncertainties. The microgrid consists of parallel connection of two Distributed Generation (DG) units and a passive load. The DG units are connected to the passive load by using the power electronics converters. The microgrid model is structurally uncertain due to the large perturbations in the load parameters. To deal with the uncertainties, a Linear Fractional Representation (LFR) of the parametrically uncertain system is obtained. To achieve robust performance, the μ-synthesis approach is applied to the derived LFR model to design a μ controller. The resultant controller is structurally...
Probabilistic dynamic multi-objective model for renewable and non-renewable distributed generation planning
, Article IET Generation, Transmission and Distribution ; Volume 5, Issue 11 , 2011 , Pages 1173-1182 ; 17518687 (ISSN) ; Caire, R ; Hadjsaid, N ; Ehsan, M ; Sharif University of Technology
2011
Abstract
This study proposes a probabilistic dynamic model for multi-objective distributed generation (DG) planning, which also considers network reinforcement at presence of uncertainties associated with the load values, generated power of wind turbines and electricity market price. Monte Carlo simulation is used to deal with the mentioned uncertainties. The planning process is considered as a two-objective problem. The first objective is the minimisation of total cost including investment and operating cost of DG units, the cost paid to purchase energy from main grid and the network reinforcement costs. The second objective is defined as the minimisation of technical risk, including the probability...
Hybrid immune-genetic algorithm method for benefit maximisation of distribution network operators and distributed generation owners in a deregulated environment
, Article IET Generation, Transmission and Distribution ; Volume 5, Issue 9 , 2011 , Pages 961-972 ; 17518687 (ISSN) ; Ehsan, M ; Caire, R ; Hadjsaid, N ; Sharif University of Technology
Abstract
In deregulated power systems, distribution network operators (DNO) are responsible for maintaining the proper operation and efficiency of distribution networks. This is achieved traditionally through specific investments in network components. The event of distributed generation (DG) has introduced new challenges to these distribution networks. The role of DG units must be correctly assessed to optimise the overall operating and investment cost for the whole system. However, the distributed generation owners (DGOs) have different objective functions which might be contrary to the objectives of DNO. This study presents a long-term dynamic multi-objective model for planning of distribution...
Control of microgrids: Aspects and prospects
, Article 2011 International Conference on Networking, Sensing and Control, ICNSC 2011, 11 April 2011 through 13 April 2011 ; April , 2011 , Pages 38-43 ; 9781424495702 (ISBN) ; Azizi, S ; Ranjbar, A. M ; Sharif University of Technology
2011
Abstract
A microgrid is a controllable component of the smart grid defined as a part of distribution network capable of supplying its own local load even in the case of disconnection from the upstream network. Microgrids incorporate large amount of renewable and non-renewable distributed generation (DG) that are connected to the system either directly or by power electronics (PE) interface. The diversity of technologies used in DGs and loads, high penetration of DGs, economic operation of DGs, dynamics of low-inertia conventional DGs and PE interfaced inertialess DGs and smart operation by means of enhanced communication infrastructure have raised challenges in widespread utilization of microgrids as...
Optimal distributed generation placement in a restructured environment via a multi-objective optimization approach
, Article 16th Electrical Power Distribution Conference, EPDC 2011, 19 April 2011 through 20 April 2011 ; April , 2011 , Page(s): 1 - 6 ; 9789644631498 (ISBN) ; Dehghanian, P ; Hosseini, S. H ; Sharif University of Technology
2011
Abstract
The increasing use of electrical energy in nowadays modern societies and industries has brought about a sharp need for more efficient means of electricity generation. It seems rather logical to increase the electricity production proportional to the increasing rate of the demand. Distributed Generation (DG) has been recently accepted to be one of the most efficient means of electricity generation, particularly near to the load centers. The DG has been also considered in the generation expansion planning of power systems. In this paper, three main factors associated with the DGs placement procedure is scrutinized through a multi-objective optimization approach. One of the main factors...
A possibilistic-probabilistic tool for evaluating the impact of stochastic renewable and controllable power generation on energy losses in distribution networks-A case study
, Article Renewable and Sustainable Energy Reviews ; Volume 15, Issue 1 , 2011 , Pages 794-800 ; 13640321 (ISSN) ; Ehsan, M ; Sharif University of Technology
Abstract
This paper proposes a hybrid possibilistic-probabilistic evaluation tool for analyzing the effect of uncertain power production of distributed generations (DGs) on active losses of distribution networks. The considered DG technologies are gas and wind turbines. This tool is useful for distribution network operators (DNOs) when they are faced with uncertainties which some of them can be modeled probabilistically and some of them are described possibilistically. The generation pattern of DG units changes the flow of lines and this will cause change of active losses which DNO is responsible for compensating it. This pattern is highly dependent on DG technology and also on decisions of DG...
Financial tools to manage dispatchable Distributed Generation economic risks
, Article International Conference on Smart Energy Grid Engineering, SEGE 2015, 17 August 2015 through 19 August 2015 ; 2015 ; 9781467379328 (ISBN) ; Rajabi-Ghahnavieh, A ; Azad, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Distributed Generation (DG) has received increasing attention during the last decade. Advantage and constraints of DG application are well known to both DG owner and electric utility. Various technologies are available for DG units among them gas GenSet is, in particular, more attractive to the investors as the technology provides the control on DG generation. However, there are various financial risks associated with dispatchable DG units that prohibit wide private investment in such technologies. This paper examines the use of financial tools to manage dispatchable DG economic risks. A comprehensive framework has been proposed to consider various economic risks to DG owner. Suitable models...
Benefits of real-time monitoring to distribution systems: dynamic thermal rating
, Article IEEE Transactions on Smart Grid ; Volume 6, Issue 4 , 2015 , Pages 2023-2031 ; 19493053 (ISSN) ; Degefa, M. Z ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
With anticipated proliferation of electric vehicles and distributed generations in near future, dynamic thermal rating (DTR) as a tool for unlocking network capacities, is becoming critical for distribution network operators. DTR is gaining a great and still growing focus of attention in today's power industries. However, potential benefits of DTR, although have been envisioned to be significant, have not yet been studied quantitatively. This paper intends to comprehensively assess the potential impacts of DTR on the performance of a realistic Finnish distribution network. For doing so, first a step-by-step procedure is devised. Then, weather data and loading information of circuits in the...