A new algorithm for distribution feeder expansion planning in urban area

When feeders are newly expanded in a distribution system, allocation of new feeders, new routes that connect from the new feeders to substations and tie-line routes to other feeders, must be determined so as to minimize installation costs of new facilities under such constraints as load-balancing, current capacity, voltage drop and geographical installation restrictions. However, it is difficult for planners to find the optimal feeder expansion plan among various candidates. In this paper, in order to support planners' decision of feeder expansion planning, the authors propose a method by which the least cost expansion facilities can be obtained through searching all the candidates that satisfy such expansion constraints as voltage drop, as well as geographical installation restrictions. In the proposed method, a dual effective gradient method, the Dijkstra method, the Ford-Fulkerson method and tabu search are employed to obtain a feeder expansion plan. Through numerical examples, the validity of the proposed method is verified.