Abstract
Optimal distribution substation placement is one of the major components of optimal distribution system planning projects. This paper proposes the application of an Imperialist Competitive Algorithm (ICA) for the optimal expansion planning of large distribution network, solving the optimal sizing, siting and timing of medium voltage substation, using related fixed and variable costs subject to any operating and optimization constraints. A step by step expansion design and planning is proposed to consider dynamic behavior of the load forecasting uncertainty, asset management and geographical constraints. In order to reach the global solution, an effective coding for the ICA parameter is developed. The value of loads' density in every site is determined by mid and long-term load forecasting program. The results show the efficiency and capability of the proposed method which has been tested on a large-scale real size distribution network.