Distributed Approaches for Grid Restoration using Grid-Forming Inverters: Status Quo and Feasibility

Effective concepts for grid restoration are vital to ensure rapid recovery in case of outages. Today’s concepts follow a centralized approach, coordinated at transmission level, where the increasing share of distributed energy resources (DERs) could enable more flexible restoration following distributed approaches. This study presents the regulatory framework for grid restoration in Germany and current developments in terms of distributed approaches. It shows that the potential of actively using DERs for grid restoration is not yet considered in the implementation. Further, a simulation-based feasibility study for distributed approaches with grid-forming inverters (GFMs) is performed, comparing the restoration of sub-grids at distribution and transmission level. The observed maximum voltage deviations and line loadings indicate that the number, location and loading of the GFMs affect the overall grid restoration success. This should be taken into account when defining (further) specifications for grid-forming capabilities and integrating GFMs into existing grids.