Structural and hierarchical partitioning of virtual microgrids in power distribution network

Nowadays, the infrastructure and technologies in conventional distribution networks (CDNs) limit its further development to smart distribution networks. One way to overcome this is to develop CDNs using interconnected virtual microgrids (VMs); however, there is no consensus for an explicit definition of VMs. Therefore, in this paper, a comprehensive discussion on VMs is conducted, and a general framework for developing VMs is proposed. The core issue for developing VMs is to identify boundaries of VMs, and most of the suggested methods are based on analyzing operating states. In this paper, a different partitioning method, which is based on the analysis of structural characteristics, is proposed. The electrical coupling strength is defined as a composite weight coefficient for the analysis of electrical connection, and the electrical modularity is used to assess the quality of the partition so as to identify boundaries of VMs. This partitioning method is applied to the IEEE 33-bus distribution network and the PG&E 69-bus distribution network, and it can quickly evaluate the partitioning quality and effectively identify the boundaries of VMs.