Power-Hardware-in-the-Loop Experiments of a Microgrid With a Grid-Forming Battery Inverter

Microgrids continue to be deployed at various scales, and they are transitioning away from using conventional generating resources to increasingly relying on inverter-based resources (IBRs) as the voltage and frequency leaders. At the San Diego Gas & Electric Company Borrego Springs Microgrid, a battery inverter was upgraded with grid-forming (GFM) capability to serve as the island leader. Hardware-in-the-loop (HIL) experiments were conducted to de-risk the field deployment. This paper presents the HIL experimental results from an HIL test bed that uses a power-hardware-in-the-loop (PHIL) interface with a power inductor that was previously developed for PHIL simulations of microgrids where the inverters need to switch modes, i.e., between grid-following and GFM as the microgrid transitions between grid-connected and islanded operation. This paper presents more details on the interface and HIL simulation results of planned islanding and load steps in islanded operation to show the effectiveness of the inverters in managing the voltage and frequency.