This study focuses on the ability of inverters to restart the grid after a blackout, known as black start. This study used two different electrical distribution systems, such as IEEE 123 and K1, to integrate Self-synchronized Universal Droop Controller (SUDC)-based inverters. A 300- and 600-node system was built based on the IEEE 123 and K1 test grid in a real-time simulator. This study included a strategy for planning high penetration of renewable energy using grid-forming inverters for a reliable and resilient supply of electricity for critical loads.