A two-stage multi-period distribution network expansion planning considering the integration of private investors

In recent years, the emerging of renewable energy resources (RERs) in distribution networks has been rapidly raised by network planners. Although the integration of RERs brings a lot of advantages to distribution networks, they impose some disadvantages such as high initial capital investment on distribution companies (DISCO). This paper proposes a new two-stage multi-period distribution network expansion planning (DNEP), in which the potential of private investor's (PIs) participation is considered in the problem. In the proposed model, the planner presents an incentive price to buy energy from PIs so that it attracts them to participate in the planning projects. This incorporation is based on a long-term contract that guarantees the benefits of both contract correspondents. The proposed model is presented as a hierarchical two-stage optimization problem where the upper stage determines the general structure of the system and the lower level considers the operational conditions. Moreover, the photovoltaic plants (PVs) and energy storage systems (ESSs) are investigated as clean and new technologies in the planning, and DISCO determines the optimal sizing and sitting of these resources regarding technical and economical assessments. The fuzzy clustering method (FCM) is used to capture the intermittency of the system loads and solar irradiance by creating a day-ahead scheme. The effectiveness of the proposed DNEP problem is evaluated through a 54-bus distribution test system and a real 104-bus test system as well. Simulation and economic results show that how PIs can play an important role in long-term planning by investing RERs.