Realistic Microgrid Test Bed for Protection and Resiliency Studies

Momentum towards realization of smart grid will continue to result in high penetration of renewable fed Distributed Energy Resources (DERs) in the Electric Power System (EPS). The drive towards resiliency will enable a modular topology where several microgrids are tied to-gather, operating synchronously to form the future EPS. These microgrids may very well evolve to be fed by 100% Inverter Based Resources (IBRs), and required to operate reliably in both grid-connected and islanded modes. Since microgrids will evolve from existing distribution feeders, they will be unbalanced in terms of load, phases, and feeder-impedances. Protection and control of such microgrids, spanning over grid-connected mode, islanded mode, and transition mode need urgent attention. This paper focuses on the control aspect to facilitate stable operation and power sharing under these modes. A detailed EMTP model of a testbed using the IEEE 13-bus system is created in PSCAD, involving multiple inverters. Control strategy, modes, and implementation of inverter controls are described, and results showing stable operation and power sharing in all modes are presented.