Stability Analysis of Distribution Networks With High Penetration of Distributed Energy Resources

Increasing penetration of distributed energy resources (DER) has already resulted in several operational challenges in the power system. While literature focuses on stability challenges to the bulk power system due to high penetration of inverter-based resources (IBR), the challenges from a distribution system becoming unstable due to high DER penetration are not sufficiently addressed. Increasing DER penetration also creates opportunities for a local resource to improve stability in the distribution network without fully relying on support from the transmission system. This work utilizes real-world distribution feeders to first analyze stability challenges due to high-DER penetration and evaluates solutions from GFM-based local resources in a distribution network. This paper then proposes a new screening or system strength index that is based on the equal area method and utilizes only steady-state information in evaluating relative stability of DER interconnections in a large distribution area. The proposed index is further utilized in identifying distribution system strength improvement with advanced inverter controls.