Planning of distributed generation considering marginal capacity cost

Distribution generation (DG) in distribution network will bring about sunk cost due to lower utilization efficiency of existing power supply equipment, which is not paid enough attention. In this paper, a DG planning method considering marginal distribution capacity cost (MDCC) is proposed in order to improve utilization efficiency of supply capacity and promote optimal allocation of power resources. Influence of DG as reinforcement alternative on MDCC is considered, and the calculation method of MDCC is proposed to reflect the charges and utilization efficiency of nodal capacity. On this basis, heuristic algorithm to lower MDCC is used to determine the site and capacity of DG. Furthermore, influence of DG on network loss and short circuit current are also considered. Finally, the results of an actual case about a 35/10 kV distribution system show the rightness and validity of the proposed method.