Multi-MicroGrids for innovative distribution networks in rural areas

MicroGrids (MGs) are one of the most promising developments for the distribution system to increase the reliability with respect to disturbances of power delivery and the resiliency of some localised areas with reference to major external events capable to cause extended black-outs. With a distribution design that allows the decomposition into small, autonomous portions like MGs, customers that are not directly involved in the fault can be supplied. In this case, the distribution system acts as a backbone that provides connectivity to several MGs. The system can be regarded as a Multi-MicroGrid (MMG). It requires rethinking the operational/planning methodologies of distribution systems to exploit the opportunities from such a novel arrangement. In this paper, a planning methodology is presented that aims at defining expansion plans for MV distribution systems with MGs, using probabilistic approaches to taking into account the variability of loads and Distributed Generation. It allows the distribution planner to find the optimal development plan of a given distribution network, particularly in rural areas. The application to realistic case studies highlights the benefits from MMG intentional islanding, with reference to the postponement of network investments and improvement of Quality of Service.