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Electrical Power Distribution Networks (EPDC), 2011 16th Conference on

Date 19-20 April 2011

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Displaying Results 1 - 25 of 68
  • Effect of distribution system specifications on voltage stability in presence of wind distributed generation [abstract only]

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    Increasing penetration of distributed generation and renewable energy such as wind farms due to various reasons including environmental and economic causes, decentralization and limits on fossil fuels increased the effects of DG on power systems. This paper presents a wide analysis of the effect of wind distributed generation (DG) on voltage stability of distribution networks. Wind farms with having induction generators, are suffering from some voltage stability problems. A test system consists of a wind farm connected to a distribution network is studied. Simulation studies are carried out using MATLAB SIMULINK software. The results show the effect of different factors such as network short circuit capacity and network X to R ratio on voltage stability of the system and the Critical values for the parameters could be determined. There is also a comparison between induction and synchronous generators in a same capacity on voltage stability problem. View full abstract»

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  • Economic evaluation of Distributed generation in semnan power grid [abstract only]

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    This paper presents the potential for wind and solar energy in city of semnan and shows how much electric energy is now produced by renewable Distributed generation. distributed generation (DG) is expected to become more important in the future generation system. This paper gives the design idea of optimized PV-Solar and Wind Hybrid Energy System for distributed generation in semnan. the most important discussions about DG is economic aspect of DG. this paper is base on the empirical weather data obtained from Semnan meteorological organization. For this hybrid system, the meteorological data of Solar Insolation, hourly wind speed, are taken for semnan (Longitude 53°.23' and Latitude 35°.34') and the pattern of load consumption of feeder 20 kv are studied and suitably modeled for optimization of the hybrid energy system using HOMER software. View full abstract»

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  • Impact of distributed generation and Interruptible load on energy supply strategies of distribution companies in day-ahead market [abstract only]

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    This paper introduces an energy supply model for a distribution company (Disco) in day-ahead electricity market. The model consists of two nested blocks, wherein, outer block maximizes Discos profits, while inner block simulates the independent system operator's (ISO's) market clearing problem and minimizes generation costs and compensation costs for interrupting load. In this model, Discos have distributed generation (DG) and Interruptible load (IL) resources and the model takes into account the Impact of other Discos' energy supply strategy. In order to consider the effect of DG and IL on Discos' energy supply strategies, the proposed model applied to an eight-bus system. View full abstract»

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  • Optimal distributed generation placement and sizing for loss and thd reduction and voltage profile improvement in distribution systems using particle swarm optimization and sensitivity analysis [abstract only]

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    Distributed generations (DGs) play an important role in distribution networks. Among many of their merits, loss and THD reduction and voltage profile improvement can be the salient specifications of DG. Studies show that non-optimal locations and non-optimal sizes of DG units may lead to losses increase, together with bad effect on voltage profile and harmonics. So, this paper aims at determining optimal DG allocation and sizing. To do so, the heuristic optimization technique named Particle Swarm Optimization (PSO) is used as the solving tool to minimize simultaneously the economic cost of overall system by changing sitting and varying sizes of DGs. In this optimization method, the investment cost of DGs and power losses are considered in order to being minimized. Firstly, a radial distribution power flow (PF) algorithm is executed to find the global optimal solution. Then, with respect to voltage profile, THD and loss reduction and by using the sensitivity analysis, PSO is used to calculate the objective function and to verify bus voltage limits. To include the presence of harmonics, PSO was integrated with a harmonic power flow algorithm (HPF). The proposed (PSO-HPF) based approach is tested on an IEEE 15-bus radial distribution system. Finally, the returning of investmental cost is calculated to show the economic justification of DG placement. These scenarios yields efficiency in improvement of voltage profile and reduction of THD and power losses; it also permits an increase in power transfer capacity and maximum loading. View full abstract»

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  • Optimal distributed generation placement in a restructured environment via a multi-objective optimization approach [abstract only]

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    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 considered in this paper is the network loss. The costs associated with the investment, operation, and maintenance of the DGs, together with the reliability worth and customer interruption cost are the other two criteria to be investigated in this paper. A multi-objective optimization approach is then proposed and the Non-dominated Sorting Genetic Algorithm II (NSGAII) as a convenient tool to deal with such a problem is utilized. The methodology well proves its applicability and efficiency by being applied to a real electric power distribution system. View full abstract»

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  • Optimal capacitor placement with consideration of voltage source harmonic distortion effect on radial distribution networks using binary particle swarm optimization (bpso) [abstract only]

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    This paper proposed a binary particle swarm optimization (BPSO) for capacitor optimal placement on radial distribution network. Harmonic distortion of voltage sources in network caused a double harmonic current injection, increasing network losses and incidence of resonance phenomenon; Therefore the issue of expression, harmonic distortion of voltage sources is considered. Moreover selected BPSO method for considering the discrete nature of the placement problem; Whereas most of the articles has been considered this problem continuously this issue caused reduction of the result accuracy to determine the size, exact location of capacitors and non-convergence of problem. Finally, The proposed method has been applied to 28-Bus IEEE standard radial distribution network to reduce loss and improve voltage profile with regard to harmonic distortion of voltage sources in various levels of network load during the one day. View full abstract»

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  • Using a hybrid evolutionary method for optimal planning, and reducing loss of distribution networks [abstract only]

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    In this paper the practical planning of distribution system includes the selection of optimal conductor size and capacitor placement in radial distribution network considering increasing rate of loads. Technical operational constraints are available conductors and capacitors, voltage limit, maximum permissible carrying current of conductors and maximum reactive power could be injected. The power loss minimization problem is solved using a hybrid method of GA and PSO, which is called HGAPSO. By applying the proposed method, final cost of network planning, losses and their cost are considerably reduced and voltage profile of the network has improved to a semi flat shape. Simulation results are investigated on a sample radial distribution network. At last the effectiveness of proposed hybrid method is proved comparing the results with obtained results from PSO. View full abstract»

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  • Loss reduction planning in electric distribution networks of IRAN until 2025 [abstract only]

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    In this paper, a loss reduction planning in electric distribution networks is presented based on the successful experiences in distribution utilities of IRAN and some developed countries. The necessary technical and economical parameters of planning are calculated from related projects in IRAN. Cost, time, and benefits of every sub-program including seven loss reduction approaches are determined. Finally, the loss reduction program, the benefit per cost, and the return of investment in optimistic and pessimistic conditions are introduced. View full abstract»

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  • A multiobjective evolutionary algorithm for distribution system reconfiguration [abstract only]

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    This paper presents an effective method-variable scaling hybrid differential evolution (VSHDE)-for solving the network reconfiguration for power loss reduction and voltage profile improvement of distribution systems. The network reconfiguration of distribution systems is to beneficially recognize load transfers so that the objective function composed of power losses is minimized and the prescribed voltage limits are satisfied. The variable scaling factor based on the 1/5 success rule is used in the VSHDE method to overcome the drawback of the fixed and random scaling factor and alleviate the problem of the selection of a mutation operator in the hybrid differential evolution (HDE). VSHDE algorithm has been applied for the test systems and the performance of the proposed method with genetic algorithms (GAs), and simulated annealing (SA). Numerical results show that the performance of the proposed method is better than the other methods. View full abstract»

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  • Loss reduction allocation to distributed generation units in distribution systems [abstract only]

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    This paper proposes a novel loss reduction allocation method in distribution systems in the presence of distributed generation (DG) units. The proposed method aims to procure the participation of each DG unit in the reduced amount of energy losses in distribution systems brought about by participation of all DG units in power market. The method is based on the assumption that DG units have private owners; hence, it provides a proper solution for distribution companies to have a fair incentive to specify which DG units are more beneficial to them. Two cooperative game theory approaches namely Shapley Value and τ Value methods are applied in order to provide fair and stable models for loss reduction allocation in distribution networks. Consistent and stable results qualify the equity and validity of the method. View full abstract»

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  • Electrical energy management of virtual power plants in distribution networks with renewable energy resources and energy storage systems [abstract only]

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    Production of energy in centralized power plants and transmitted via transmission lines to the customers is always with high power losses. Distributed generation (DG) especially renewable energy resources (RES) and energy storage systems (ESS) through distributed system are very cost saving and sometimes inevitable. If these small DGs want to connect to power system and participate in energy market directly, both distribution and energy market would have many problems with control such a high amount of information and small supplies of DGs. Application of virtual power plant (VPP) as an aggregation of some DGs with own local energy management system and some fix and variable loads is a suitable solution for DGs and networks problems. VPP has a main energy management too. So they can be in contact with distribution system operator and each local energy management systems of each DCs via main energy management system, so the VPP can make decisions when and which and how much each DCs supply. In the other hand random type of electrical productions of RESs and also shortage of energy at peak load times and necessity of energy storage make electrical energy management more complicated. All energy managements in virtual power plants were without RESs and ESSs so in this publication electrical energy management for a VPP with considering some RESs and ESSs will be done via three different scenarios and MATLAB tools was applied to evaluate the units control dispatch to the optimal system configuration. View full abstract»

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  • Optimal placement of reactive power compensators in a test radial distribution network [abstract only]

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    In a distribution system and especially in rural network or industries which are so far from HV substation, it is possible to increase the power quality by compensating of reactive power using var compensators. But these equipments are expensive and need to large scale of investment. This paper presents an applicable method to define the number of static reactive power generating units and their optimal position in radial networks. this method improve voltage profile and power losses. To solve the optimization problem, simulated annealing algorithm has been used to minimize a dual fitness function consist of voltage drop & power losses. The proposed method use an index like interested rate to choose the best number and location of var compensators. Finally, the compensating algorithm is implemented on a test feeder called “seda va sima” which is one of 20 kVs feeders in Bardsir city, Kerman, Iran. The simulation results using Matlab 2009a are presented which verify the effectiveness of proposed method. View full abstract»

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  • Comparison of several clustering methods in the case of electrical load curves classification [abstract only]

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    In the electricity market, it is highly desirable for suppliers to know the electricity consumption behavior of their customers, in order to provide them with satisfactory services with the minimum cost. Information on customers' consumption pattern in the deregulated power system is becoming critical for distribution companies. One of the suitable tools for extracting characteristics of customers is the clustering technique. Selection of better methods among several existing clustering methods should be considered. Therefore, in this paper, we evaluate the performance of Classical K-Means, Weighted Fuzzy Average K-Means, Modified Follow the Leader, Self-Organizing Maps and Hierarchical algorithms that are more applicable in clustering load curves. The performances were compared by using two adequacy measures named Clustering Dispersion Indicator and Mean Index Adequacy. View full abstract»

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  • Simultaneous implementation of optimal demand response and security constrained Unit Commitment [abstract only]

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    Unit Commitment is the optimization process for minimizing the total cost of real power generation meeting the generating units and the system constraints. With the restructuring in power systems, the matter of great concern is the fuel cost and consequently electricity price increase in some hours of the day. Accordingly, the optimum performance of Demand Side Management (DSM) has been gaining great attention recently. In this paper, the effect of the optimum performance of Emergency Demand Response Program (EDRP) on the cost of the unit commitment problem considering the line flow constrains is scrutinized. Due to the fact that the simultaneous adoption of the unit commitment and demand response program is a complex non-linear problem with numerous discrete and continuous variables, it is logical to use the linear programming technique to effectively deal with these parameters. Having the GAMS software and CPLEX method exploited, the proposed method proved its effectiveness by numerically applied to a typical 3-bus and the IEEE 24-bus systems. View full abstract»

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  • Asset management: Condition based monitoring effect on utility coasts and lose power consumption [abstract only]

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    Operating distribution networks in southern region of Iran located in northern coasts of Persian Gulf and Oman Sea requires special conditions. Environmental conditions like high temperature and humidity, Sunlight severity, very low raining, Obstacles in the air in addition with conditions like high energy consumption per capital, fast growth of energy demand because of new air conditioning systems and immigration of people to this region and converting this region to the largest industrial zone of Iran, all caused a very fast age reduction in distribution networks installed, so that the rate of aging has been estimated up to 40%. Considering above mentioned conditions and our experts' high load of work for operating and maintaining the old installations in addition with their efforts for avoiding the black-outs, Objectives of the Hormozgan Electric Power Distribution Co for reducing the black-outs caused rescheduling old preventive maintenance plans. This paper is a review of Hormozgan Electric Power Distribution Company's experiences using thermographs for preventive maintenance and inspection in Hormozgan region. In this project, 151 middle voltage feeders in 5,700 Km grid were inspected and 2,200 lose connections were discovered. Fixing these loose connections resulted reducing 10.5 MW power losses and reduce the costs of operation up to 39 million USD during the year 2009. View full abstract»

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  • Significance of the role and implementation of strategic management in electric Distribution companies as expected by TAVANIR Co [abstract only]

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    In this article, it is primarily dealt with the role and importance of strategic planning parameters within electric Distribution companies , by comparing the indexes of strategic management (in compiling section) in some of the superior companies and some other companies according to evaluation and classifying them in 2009, that are performed by TAVANIR co. Then, by presenting an applicable example by using the comprehensive frame of compilation strategy within the expection of TAVANIR co., it will be dealt with preparing the matrix for internal/ external factors parameters to provide the swot matrix and the expression of utilizing the strategic compilation, by a case study in Isfahan electric Distribution co. View full abstract»

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  • Planning strategic in the form of scientific and practicable model and format of integration workshop (Hormozgan Electric Distribution Company selected as a case study) [abstract only]

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    The objective of this paper is to study the organization's strategic planning status based on literature sheet and in case of existence of conflicts the suitable corrective measures will apply. Literature sheet is a measurement tool for measuring the organization. Indeed we analysis the organization with the view of literature sheet and the problems determines. And in order to achieve what was mentioned, seven steps introduced that with executing of each step in the model the possibility of senior management decisions to improve strategic planning are facilitate. And in continue operating the program is prepared and executed. View full abstract»

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  • Technical and economic evaluation of implementing outage management system in urban distribution systems in Iran [abstract only]

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    Faults in MV systems are the cause of almost 70 percent of outages in power system. by using suitable outage management methods, amount of power outages will be reduced in large extent. In Iran, traditionally outage management system was conducted by trial and error methods and relied on operators' experience. The ever-increasing expansion of distribution networks has made it impossible to use traditional outage management systems. Outage management systems depend upon load type, load sensitivity, network type, amount of accumulation of load and population, and being rural or urban network. In this paper, at first a technical assessment for implementing outage management methods in distribution systems of Iran is carried out. An economic assessment of implementing outage management system in urban distribution systems of Iran with dense population is conducted. For this purpose a sample network of Afsarieh area of Tehran has been chosen. View full abstract»

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  • Review of UWB technology specifications and benefits as a powerful technology to develop power distribution grid automation techniques [abstract only]

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    In automation of power distribution grids, type of communication and protocols used to transfer data between various points are important challenges. In this paper one of newly advanced technologies which can be used to improve this field of grid automation is investigated. On February 14, 2002, FCC adopted the first report and order that permitted the commercial operation of ultra wideband (UWB) technology with a frequency band from 3.1GHz to 10.6 GHz. After that, using UWB technology was increasing as one of the most reliable technologies for high data rate wireless communications and various applications. In this research, the basic theory and new applications of this technology are reviewed and the subjects ahead to improve wireless applications are discussed and analyzed. View full abstract»

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  • Control system design for energy optimized dynamic voltage restorer [abstract only]

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    Voltage deviations, often in the form of voltage sags, can cause severe process disruptions and result in substantial economic loss. The Dynamic Voltage Restorer (DVR) has been proposed to protect sensitive loads from the effects of voltage sags on the distribution feeder. The compensation capability of a DVR depends primarily on the maximum voltage injection ability and the amount of stored energy available within the restorer. In this paper a new phase advance compensation (PAC) strategy for the DVR is proposed in order to enhance the voltage restoration property of the device. The scheme requires only an optimum amount of energy injection from the DVR to correct a given voltage sag. Using the proposed method it can be shown that a particular disturbance can be corrected with less amount of storage energy compared to that of existing in-phase boosting method. In the end a closed-loop controller that consists of an inner current loop and an outer voltage loop is also incorporated into the DVR system. View full abstract»

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  • Thermal coefficient measurements of typical distribution transformers operating under imbalance conditions [abstract only]

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    Transformers play a key role in power distribution networks. A reliable and endless supply of electricity is highly dependent on good operation of these elements. A huge number of customers are directly supplied via any of the transformers. Loading of transformers under imbalance conditions is an important factor that influences the life of their insulation. This paper primary refers to thermal coefficients measurement and life assessment of two typical distribution transformers with the same parameters but different operating conditions. View full abstract»

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  • Introduction of a novel operational framework for distribution network considering distributed generations and load elasticity effect [abstract only]

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    Presence of distributed generations (DGs) in the distribution systems have altered the operation of these networks. In this context, distribution network operator (DNO) needs to minimize the operational costs of the network while considering the DGs effect on the other technical parameters of the distribution system such as active and reactive power losses and voltage profile. One means of dealing with such complexity is through the use of a multiobjective operational framework. This paper introduces a novel multiobjective paradigm for operating the distribution networks with distributed generation which includes a wide range of operational issues. This model considers the demand sensitivity with respect to the network price and incorporation of interruptible loads to examine how operational decisions are affected by load elasticity effects. It is also shown that one of the useful features of this model is its objective function sensitivity factors that through the use of them, the location of the prospective distributed generation units can be obtained. The proposed methodology is tested on a 33-bus distribution network. View full abstract»

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  • Clustering load distribution substation based on similarity of load curves using statistic-fuzzy methods [abstract only]

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    Having accurate information of load is one of the key points of the proper operation and investment in distribution networks. Identification and classification of substation loads and consumer services is the first step in: estimation and reconstruction of load distribution substations, proper operation, load forecasting, comprehensive plans and other studies. So far, different methods based on neural networks and also fuzzy methods have been presented for this aim. In this study, a statistic-fuzzy method is used for clustering substations loads. In this method, recorded load curves in statistical history are used for generation membership function of fuzzy relationship matrix. After inner multiplication of fuzzy matrix, nearness degree coefficient of load curves which it shows the similarity of curves is calculated. At the end, this method is used in a real geographical area (Bandarabbas) and the results are presented. View full abstract»

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  • Determining of annual distribution feeder configuration using load curves clustering [abstract only]

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    The power that flow in distribution feeders is the sum of commercial, industrial and residential loads, so it has a time varying characteristic. The switching operation problem in distribution systems is to find the optimal switching time and the optimal candidates so that operation costs become minimized. In this paper a novel method is proposed to determine annual feeder reconfiguration scheduling based on load profile. In this method the concept of load curves clustering has been used to cluster the annual load curves into several time intervals. Clustering is done based on size and shape of daily load curve. Using a harmony search algorithm (HSA), optimal configuration of each interval is obtained to minimize objective function consist of energy losses and network reliability costs. Simulation results show the effectiveness of the proposed method and its capability to find the optimal solution. View full abstract»

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  • Effect of two-circuit lines on unbalanced distribution systems [abstract only]

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    Distribution power flow analysis is one of the most important resources for proper distribution systems operation. Distribution power flow problem is very different from transmission power flow problem due to radial structure, considerable R/X ratio, load unbalance and existence of light phase. In this paper, the impedance matrix based power flow program is expanded through modelling mutual effects in two-circuit lines. Besides, the effect of this modelling on the impedance matrix based power flow results of a medium-voltage test system is investigated using MATLAB. A sensitivity analysis is done on the effect of load variation on bus voltages and feeder currents of the system. The effect of load unbalance on voltage difference among different phases of the same bus is also obviously demonstrated. View full abstract»

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