The Distribution Network Reconfiguration Using Index Measurement Technique

As modern distribution networks have been developing fast, the network is increasingly complex, the make up of power consumer has changed greatly, and consumer's require -ement for improving power quality and supply reliability is more and more stronger,it is difficult to keep a large-scaled distribution network operating safely and economically only by manual management, and even difficult to satisfy the imperative requirement of power utilities for reducing losses and enhancing service quality. Distribution network recon-figration is an efficient measure to enhance power network's operating efficiency, supply reliabi- bility and power quality.In normal operating state, network reconfigur- ation can be undertaken to improveoperation efficiency, losses minim ization and load balancing. When the system is out of service, The reconfiguration is used to find a restoration solution and implemented to provide as much supply as possible to the cust omers until the system is returned to the normal state.As part of DMS(distribution Management System) advan ced applicationsoftware, the distribution network reconfigura tion plays an important role in thelow cost and high reliability of electricity .The feeder reconfiguration for loss minimization in distri bution systems is realized by changing the status of sectional-izing and tie switches. However, there are many switches in a distribution system. So it is difficult to construct a mathematic model of the relationship between the loads and the switch states with the minimum losses directly.The paper introduce some fashionable distribution net work arithmetic and advantage or disadvantage following introduce distribution network predigest analyzing elements andequivalent load predigestionmodel.subsequently the branch exchange algorithm is one of the methods conce -rning distr-ibutionnetwork reconfiguration to reach loss reduction. It belongs to heuristic optimization methods. Since loads are varying all the time, we should adjust the topology to reduce the power losses. However, each time load varies, traditional heuristic methods need a great amount of iterations to reach optimization. And each move involves power flow computat -ion. So these methods are not suitable for online applications. In this paper a new technique for three-phase load balancing by network reconfiguration is presented.The loading congdition of the branches and the overall system are determined using the proposed indices and the index values have to be minimum for optimum load balancing .For optimal load balancing condition,the branch load-balancing indices will be nearly equal to each other ,and also closely approxim ate to the overall system load-balancing index. The technique is developed based on a two-stage searching approach to the switching operation.In the proposed method a loop-index hasbeen derived which is used in the first stage to identify the maximum load-balancing loop of the network.To find the switching operation to be executed in the loop to obtain an optimal network configuration for load balancings branch-exchange index is used in the second stage.The developed technique reduces numerous load-flow runs and also the computational requirements.The proposed methos will be a most useful tool for real-time control of automated distribution system for load balancing.