Integrated Planning of Distributed Generation Sources and Networks in Distribution Systems

Distributed generation (DG) sources are becoming attractive alternatives for power system planners. When DG units participate in the expansion of distribution systems, the investments for grid upgrade can be deferred or reduced. However, the uncertainties of DG power production may cause difficult planning. In this paper, integrated planning problems of DG sources and networks in distribution systems are analyzed. A new two-step procedure is proposed. In the first step, all new lines are added to the network and an expectation planning model is presented. Stochastic simulation and genetic algorithm are applied to obtain the optimal ratings of DG units. In the second step, a heuristic successive backward algorithm based on a sensitivity index is presented. The sensitivity index is defined as the system capacity reserve decrease by the total investment cost of the line to be removed. According to the index, the redundant lines in the network can be eliminated. The effectivity of the proposed method is demonstrated through a practical test system.