International Journal on Electrical Engineering and Informatics ‐ Volume 5, Number 3, September 2013 Radial distribution systems reconfiguration considering power losses cost and damage cost due to power supply interruption of consumers Sasan Ghasemi and Jamal Moshtagh Department of Electrical and Computer Engineering, University of Kurdistan, Sanandaj, PO Box 416, Kurdistan, Iran Abstract: Distribution system reconfiguration problem is a complex optimization process to find a structure with minimum losses in which the satisfaction of both sides, that is consumers and distribution system companies, need to be met. One of the most significant parameters in this regard is to increase the reliability of system. This parameter, on one hand, increases the satisfaction of power consumption and on the other hand, improves the economic benefits of distribution companies. Distribution system reconfiguration, considering the reliability parameters, seems to make the attempts to solve the problem of optimization difficult. In this paper, a new heuristic approach for distribution system reconfiguration in order to decrease the power losses cost and damage cost due to power supply interruption of consumers has been presented. Radial network construction and all energized nodes constraints are the most important ones that should be considered in distribution system reconfiguration problem. Hence, in this paper a new codification is proposed which is computationally efficient and guarantees to generate only feasible radial topologies all times. In order to illustrate the performance of proposed heuristic method, modified 33-bus and 119-bus distribution networks have been employed which have led to the desired results. Keywords: Damage cost due to power supply interruption, heuristic algorithm, new codification, power losses cost, reconfiguration, reliability. 1. Introduction Distribution network reconfiguration refers to the change of operation configuration by altering the topological state of open/closed of some electric lines. Network reconfiguration is just feasible for those networks which are meshed. In a distribution network the numbers of lines “in operation” and “out of service” are determined. The states of these sets of lines, subjected to maintaining the radial structure, can change. These changes ought to lead to objective function improvement which, of course in this regard, operating and consumption power constraints should be taken in to account. Paper [1] has employed load transfer from a feeder to neighbor feeder, using a series of formulas to assess power losses variation without calculating the power flow. In [2] searching techniques is presented which are based on “branch exchange” strategy. Modified Tabu Search has been utilized for distribution system reconfiguration [3]. An optimum power flow concept for active power losses minimization is used in paper [4] and the same concept is applied in order to minimize the energy losses [5]. A heuristic approach to find structure with minimum losses as well as a random walks-based technique in order to losses prediction has been suggested [6]. In order to reduce losses, considering distributed generation, a method has been used [7]. Considering reliability related issues in the reconfiguration process is a new approaching manner in the technical literature, with studies approaching different aspects. In [8], a reconfiguration approach to reduce the interruption numbers for a distribution network has been proposed. In [9], network reconfiguration problem, considering network reliability and power losses has been solved. Reconfiguration models that minimize a weighted sum of Received: May 8 th , 2013. Accepted: August 22 nd , 2013 297