Reconfiguration of electric distribution networks for resistive line losses reduction
TL;DR: In this paper, the authors describe a heuristic method for the reconfiguration of distribution networks in order to reduce their resistive line losses under normal operating conditions, characterized by convergence to the optimum or a near-optimum solution and the independence of the final solution from the initial status of the network switches.
Abstract: The authors describe a heuristic method for the reconfiguration of distribution networks in order to reduce their resistive line losses under normal operating conditions. The proposed approach is characterized by convergence to the optimum or a near-optimum solution and the independence of the final solution from the initial status of the network switches. The methodology has been implemented in a production-grade computer program, DISTOP (Distribution Network Optimization). The compensation-based power flow technique developed at Pacific Gas and Electric Company for the efficient solution of weakly meshed distribution networks is an essential part of this loss reduction methodology. Important implementation aspects of the methodology and the results of its application to several realistic distribution networks are presented. Numerous test results have indicated that the proposed technique is computationally robust and efficient and, hence, suitable for both planning and operations studies. >
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TL;DR: In this paper, a meta heuristic Harmony Search Algorithm (HSA) is used to simultaneously reconfigure and identify the optimal locations for installation of DG units in a distribution network.
Abstract: This paper presents a new method to solve the network reconfiguration problem in the presence of distributed generation (DG) with an objective of minimizing real power loss and improving voltage profile in distribution system. A meta heuristic Harmony Search Algorithm (HSA) is used to simultaneously reconfigure and identify the optimal locations for installation of DG units in a distribution network. Sensitivity analysis is used to identify optimal location s for installation of DG units. Different scenarios of DG placement and reconfiguration of network are considered to study the performance of the proposed method. The constraints of voltage and branch current carrying capacity are included in the evaluation of the objective function. The method has been tested on 33-bus and 69-bus radial distribution systems at three different load levels to demonstrate the performance and effectiveness of the proposed method. The results obtained are encouraging.
852 citations
Cites methods from "Reconfiguration of electric distrib..."
...Based on the method of Merlin and Back [1], a heuristic algorithm has been suggested by Shirmohammadi and Hong [2]....
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TL;DR: In this paper, the loss minimum reconfiguration problem in the open loop radial distribution system is formulated as a mixed integer programming problem and a detailed solution methodology by the use of genetic algorithm is outlined.
Abstract: The loss minimum reconfiguration problem in the open loop radial distribution system is basically one of complex combinatorial optimization, since the normal open sectionalizing switches must be determined appropriately. The genetic algorithm was successfully applied to the loss minimum reconfiguration problem. In the proposed algorithm, strings consist of sectionalizing switch status or radial configurations, and the fitness function consists of the total system losses and penalty value of voltage drop and current capacity violations. The loss minimum reconfiguration problem is formulated as a mixed integer programming problem. The essential components of the genetic algorithm are briefly described. A detailed solution methodology by the use of genetic algorithm is outlined. Numerical examples demonstrate the validity and effectiveness of the proposed methodology. >
700 citations
TL;DR: In this article, a power-flow-minimum heuristic algorithm for determining the minimum loss configuration of radial distribution networks is presented. But the algorithm is based on the concept of optimum flow pattern which is determined by solving the KVL and KCL (Kirchoff's voltage and current laws) equations of the network.
Abstract: The authors report a power-flow-minimum heuristic algorithm for determining the minimum loss configuration of radial distribution networks. The algorithm is based on the concept of optimum flow pattern which is determined by solving the KVL and KCL (Kirchoff's voltage and current laws) equations of the network. The optimum flow pattern of a single loop formed by closing a normally open switch is found, and the flow pattern is established in the radial network by opening a closed switch. This process is repeated until the minimum loss configuration is obtained. A simple, fast and approximate power flow method has also been developed to assist the reconfiguration algorithm. The proposed reconfiguration algorithm has been found to give better network configuration than those obtained by some other methods. >
627 citations
TL;DR: In this paper, a mixed-integer conic programming formulation for the minimum loss distribution network reconfiguration problem is proposed, which employs a convex representation of the network model which is based on the conic quadratic format of the power flow equations.
Abstract: This paper proposes a mixed-integer conic programming formulation for the minimum loss distribution network reconfiguration problem. This formulation has two features: first, it employs a convex representation of the network model which is based on the conic quadratic format of the power flow equations and second, it optimizes the exact value of the network losses. The use of a convex model in terms of the continuous variables is particularly important because it ensures that an optimal solution obtained by a branch-and-cut algorithm for mixed-integer conic programming is global. In addition, good quality solutions with a relaxed optimality gap can be very efficiently obtained. A polyhedral approximation which is amenable to solution via more widely available mixed-integer linear programming software is also presented. Numerical results on practical test networks including distributed generation show that mixed-integer convex optimization is an effective tool for network reconfiguration.
470 citations
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...The implementation in [4] has been improved by Shirmohammadi and Hong in terms of more elaborate network and load modeling [5]....
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24 Jul 2011
TL;DR: In this paper, a multi-period AC optimal power flow (OPF) is used to determine the optimal accommodation of (renewable) distributed generation in a way that minimizes the system energy losses.
Abstract: The problem of minimizing losses in distribution networks has traditionally been investigated using a single, deterministic demand level. This has proved to be effective since most approaches are generally able to also result in minimum overall energy losses. However, the increasing penetration of (firm and variable) distributed generation (DG) raises concerns on the actual benefits of loss minimization studies that are limited to a single demand/generation scenario. Here, a multiperiod AC optimal power flow (OPF) is used to determine the optimal accommodation of (renewable) DG in a way that minimizes the system energy losses. In addition, control schemes expected to be part of the future Smart Grid, such as coordinated voltage control and dispatchable DG power factor, are embedded in the OPF formulation to explore the extra loss reduction benefits that can be harnessed with such technologies. The trade-off between energy losses and more generation capacity is also investigated. The methodology is applied to a generic U.K. distribution network and results demonstrate the significant impact that considering time-varying characteristics has on the energy loss minimization problem and highlight the gains that the flexibility provided by innovative control strategies can have on both loss minimization and generation capacity.
462 citations
References
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TL;DR: In this paper, a scheme that utilizes feeder reconfiguration as a planning and/or real-time control tool to restructure the primary feeder for loss reduction is presented.
Abstract: Feeder reconfiguration is defined as altering the topological structures of distribution feeders by changing the open/closed states of the sectionalizing and tie switches. A scheme is presented that utilizes feeder reconfiguration as a planning and/or real-time control tool to restructure the primary feeder for loss reduction. The mathematical foundation of the scheme is given. The solution is illustrated on simple examples. >
1,297 citations
TL;DR: In this article, a power flow method is described for solving weakly meshed distribution and transmission networks, using a multiport compensation technique and basic formations of Kirchoff's laws.
Abstract: A power flow method is described for solving weakly meshed distribution and transmission networks, using a multiport compensation technique and basic formations of Kirchoff's laws. This method has excellent convergence characteristics and is robust. A computer program implementing this scheme was developed and successfully applied to several practical distribution and transmission networks with radial and weakly meshed structures. The method can be applied to the solution of both the three-phase (unbalanced) and single-phase (balanced) representation of the network, however, only the single-phase representation is treated in detail. >
1,108 citations
01 Jan 1975
482 citations
TL;DR: In this article, the authors presented an algorithm and presented computer results for minimizing the losses in a loop distribution system based on the remote operation of sectionalizing switches on feeders interconnecting different substations.
Abstract: This paper addresses a subproblem related to distribution automation. It outlines an algorithm and presents computer results for minimizing the losses in a loop distribution system based on the remote operation of sectionalizing switches on feeders interconnecting different substations. The minimization is carried out subject to the voltage-drop, line-capacity and substation-capacity constraints. Computational experience with a system of realistic size indicates that the procedure proposed here is valid and effective in practical operations.
125 citations