A New Distribution Network Reconfiguration Approach using a Tree Model

Power loss reduction is one of the main targets in power industry and so in this paper, the problem of finding the optimal configuration of a radial distribution system for loss reduction is considered. Optimal reconfiguration involves the selection of the best set of branches to be opened ,one each from each loop, for reducing resistive line losses , and reliving overloads on feeders by shifting the load to adjacent feeders. However ,since there are many candidate switching combinations in the system ,the feeder reconfiguration is a complicated problem. In this paper a new approach is proposed based on a simple optimum loss calculation by determining optimal trees of the given network. From graph theory a distribution network can be represented with a graph that consists a set of nodes and branches. In fact this problem can be viewed as a problem of determining an optimal tree of the graph which simultaneously ensure radial structure of each candidate topology .In this method the refined genetic algorithm is also set up and some improvements of algorithm are made on chromosome coding. In this paper an implementation of the algorithm presented by [7] is applied by modifying in load flow program and a comparison of this method with the proposed method is employed. In [7] an algorithm is proposed that the choice of the switches to be opened is based on simple heuristic rules. This algorithm reduce the number of load flow runs and also reduce the switching combinations to a fewer number and gives the optimum solution. To demonstrate the validity of these methods computer simulations with PSAT and MATLAB programs are carried out on 33-bus test system. The results show that the performance of the proposed method is better than [7] method and also other methods.

• E. Dolatdar
• S. Soleymani
• B. Mozafari

• Distribution System
• Reconfiguration
• Loss Reduction
• Graph Theory
• Optimization
• Genetic Algorithm

[1] A. Merlin, H. Back, "Search for a minimal-less operating spanning tree configuration in an urban power distribution system" Proceedings of 5th Power System Computation Conference (PSCC),
Cambridge , UK ,( 1975 ) , pp. 1-18.
[2] M.E.Baran,FF.Wu,Network reconfiguration in distribution systems for loss reduction and load balancing, IEEE Trans. Power Delivery 4
(2) (1989) 1401-1407.
[3] J.-.Fan, L. Zhang, J. D. McDonald, Distribution network reconfiguration :
single loop optimization , IEEE Trans. Power Syst. 2 (3) (1996).
[4] H.D. Chiang, R.J. Jumeau ,Optimal network reconfiguration in
distribution systems , part 1a new formulation and a solution methodology, IEEE Trans. Power Deliv. 5 (4) (1990) 1902_/1909.
[5] K. Nara, A. Shiose, M. Kitagawa, T. Ishihara, Implementation of
genetic algorithm for distribution system loss minimum
reconfiguration, IEEE Trans. Power Systems 7 (3) (1992)
1044_/1051.
[6] S.K.Goswami , S.K.Basu ,A new algorithm for the reconfiguration of
distribution feeders for loss minimization , IEEE Trans On Power
Delivery , Vol 7 , No 3, July 1992.
[7] R. Srinivasa Rao, S. V. L. Narasimham, A New Heuristic Approach
for Optimal Network Reconfiguration in Distribution Systems,
International Journal of Applied Science, Engineering and Technology 5(1) ( 2009).
[8] M. A. Kashem,V. Ganapathy, G.B. Jasmon, and M. I. Buhari, "A
Novel model for loss minimization in distribution networks", IEEE
International Power Technologies 2000 Conference on Electric Utility
deregulation, restructuring at City University London, 4-7 April
2000,pp. 251-256.
[9] Holland JH. Adaptation in natural and artificial systems. Michigan: University of Michigan Press; 1975.
[10] RM Saloman Danaraj, Shankarappa F Kodad and Tulsi Ram Das ,
"An algorithm for radial distribution power flow in Complex mode
including voltage controlled buses" , Indian Journal of Science and
Technology , Vol.1 No.2 (Dec. 2007).