A practical approach to the conductor size selection in planning radial distribution systems

This paper presents a new approach to the optimization problem of conductor size selection in planning radial distribution systems. In this study, a multisection, branching feeder model with nonuniform load distribution has been chosen to best approximate actual conditions found in most distribution systems. Since the optimization problem is formulated as an integer programming problem, it is difficult to solve such a large-scale problem accurately. Therefore, in order to find an approximately optimal solution quickly, the authors have developed a simple, practical approach, which relies on the combined usage of an economical current density based method and a heuristic index directed method. This approach needs no sophisticated optimization technique and, thus, is easy to implement. Because of the practicality of its features, the proposed approach can be a useful tool for distribution engineers. It is presently in use at several electric power bureaus, such as the Chongqing Electric Power Bureau in China. The detailed results of the designs of some typical radial feeders using the proposed approach are also presented and discussed