New Reliability Indices for Microgrids and Provisional Microgrids in Smart Distribution Systems

The construction of provisional microgrids paired with microgrids was recently introduced taking into consideration, the less critical zones of the distribution system. Similar to the microgrids, the provisional microgrids have distributed generators and a master controller. But these provisional microgrids cannot switch to islanded mode as a single entity as in the case of microgrids. Instead, they move to islanded mode along with the coupled microgrid, thus meeting the economic and reliability requirements of the less sensitive zones of the distribution system. This work first proposes few new device-based reliability indices for the sustained faults that cater to the new requirements arising due to the presence of distributed generators all over the system, embedded in clusters of microgrids and provisional microgrids. Secondly, considering the occurrences of temporary faults in similar systems, another new load-based reliability index is proposed. Later, for the chosen example distribution system with 69-buses, the existing reliability indices, and the proposed new indices are calculated. At last, the influence of these indices on generation expansion planning problems like placement and sizing of the distributed generators, construction of clusters of microgrids and provisional microgrids, and economic decisions on scheduling of maintenance is discussed in detail.