Resiliency Augmented Hybrid AC and DC Distribution Systems With Inverter-Dominated Dynamic Microgrids

In this paper, the implementation of inverter-dominated dynamic microgrids (MGs) in hybrid AC/DC distribution systems is discussed. Compared to conventional networked MGs structure, dynamic MGs operate with varying electric boundaries, which enables more flexible system operating topologies and power flow options. A control framework is developed for hybrid AC/DC distribution systems. The entire feeder is sectionalized into multiple dynamic MGs that interact at varying points of interconnection (POIs). A set of distributed controllers is proposed to coordinate multiple inverter-interfaced distributed generators (DGs) and interlinking converters (ICs) across the hybrid AC/DC feeders under autonomous operation. Various control modes are developed for the system to operate under either static topology or reconfigure as requested. Secondary regulations over the system operating frequency and voltage are enabled in both AC and DC subgrids, along with proportional power sharing among DGs. Dedicated control efforts are developed to achieve seamless system topology transitions, and the operational stability of the proposed controllers is analyzed. The performance of the proposed work in augmenting the operation resiliency of a hybrid AC/DC test feeder is validated using comprehensive case studies.