A geometrical approach for network reconfiguration based loss minimizationin distribution systems

Network reconfiguration is one of the feasible methods for reducing the dis tribution network loss in which the power flow in the distribution network is altered by opening or closing the appropriate switches on the feeders. A geometrical approach for loss minimization is presented in this paper, in this method, each loop in a network is represented as a circle, which is de rived from the relationship between the change of loss due to the branch-ex change and the power-flows in the branches. If there is no change of loss i n the system, then all the circles touch each other at the (0,0) coordinate and the circles with no loss-change are called zero loss-change circles. T he maximum loss-reduction loop in the network is identified by comparing th e radii of all the zero loss-change circles. The corresponding loop of the largest zero loss-change circle gives the maximum loss reduction in the net work. Then the possible branch-exchanges in the maximum loss-reduction loop are investigated by comparing the size of the circle for every branch-exch ange. If the power losses are reduced due to a branch exchange, the size of the circle diminishes and hence the smallest circle gives the maximum loss -reduction and the corresponding branch-exchange is considered to be the be st candidate for maximum loss-reduction. The performance of the proposed te chnique is tested on a 69-bus distribution system, and test results show th at the method is found to reduce the computational effort and time consider ably by reducing the numerous load-flow studies as compared to the method o f Baran and Wu [IEEE Trans. Power Delivery, 4(2) (1989) 1401). (C) 2001 Els evier Science Ltd. All rights reserved.