Advanced Inverter Interactions With Electric Grids

The evolution of advanced inverter-based resources (IBR) is closely coupled with the growth of their applications in electric power networks. Most applications of inverters during this transition were grid-following (GFL) inverters. As IBRs gradually displaced rotating synchronous generators in electric power grid applications, issues such as the behavior of low-inertia grids, local needs for voltage support, and ride-though requirements led to the first interconnection requirements. The initial DER standard, IEEE Std 1547-2003, had to be adapted to the new context and led to the revised standard, IEEE Std 1547-2018 and later the IEEE Std 2800-2022 for transmission IBR systems. In this article, the various inverter operating modes and functions of modern inverters are described. A focus on the comparison of GFL and grid-forming (GFM) inverters based on a more comprehensive white paper developed by the SCC-21 Task Force on Advanced Inverters supporting industry standards is needed in the next few years to reduce system-wide IBR events on the electric system.