Upgrading Conventional Distribution Networks by Actively Planning Distributed Generation Based on Virtual Microgrids

In addition to active energy management, this article proposes active planning as another critical feature of active distribution networks (ADNs). To develop this set of tasks, this article introduces a three-layer active planning framework consisting of a physical layer, cyber layer, and socioeconomic layer. Furthermore, a three-step developing strategy for ADNs based on a virtual microgrid (VM) is put forward. Then, according to this framework, this article focuses on a specific and fundamental issue that often arises: the optimal allocation of distributed generation (DG). A two-stage scheme based on VMs is a proposed solution. In the first stage, VM boundaries are determined based on the characteristics of a network structure. Using the identified VM boundaries as constraints, a bilevel hierarchical optimization method is applied to determine the optimal DG allocation in the second stage. The proposed method is verified in the popular PG&E 69-bus distribution network.