Pilot testing of a GPS-based autonomous synchronized microgrid using digital grid routers

An independent microgrid, comprised of several grid-forming inverters, has been successfully demonstrated. These inverters synchronize with an accurate internal clock corrected by global positioning system (GPS) signals. Within this microgrid, the inverters are capable of evenly distributing the load or adjusting load distribution according to individual requirements. Additionally, the microgrid can connect asynchronously with the main grid in grid-following mode to regulate power import and export. The demonstration tests were conducted using three 10 kW grid-forming inverters known as digital grid routers (DGRs). Referred to as the “cell grid”, this microgrid behaves similarly to a synchronous main grid supported by multiple synchronous generators. • DGR operates autonomously without a robust main power source. • Frequency stability is maintained even with a small capacity ratio main power supply. • Black-start and fault ride-through (FRT) capabilities are attainable.