Optimal model for future expansion of radial distribution networks using mixed integer programming

One of the objectives of power distribution system planning is to minimise the total cost of feeders in the future expansion of distribution system. The problem is subjected to a few constraints. In the general case, solving this problem is not an easy task. Therefore, different methods such as branch and bound techniques or branch exchange method, etc. have been proposed in the literature for simplifying the problem. In this paper, a new two step planning technique which uses both the minimum spanning tree concept and the mixed integer programming (MIP) formulation has been suggested. In the first step, between all the potential trees of a future network, some of the trees which are near optimum routing are selected. In the second step, between these trees, the one with the minimum cost which satisfies all the constraints will be chosen. This method can find the optimal solution for small as well as large networks. Most of the existing methods can not guarantee the optimal solution for large networks but a near optimum solution. This approach reduces the computational effort and guarantee a reliable solution