Protection and Control Challenges of Low-Voltage Networks with High Distributed Energy Resources Penetration - Part 2: Impact Assessment and Mitigation Strategy

This is the second part of a two-part paper series. In the Part 1 paper, the authors summarize the utility workshop outcomes and low-voltage network modeling approaches. In this Part 2 paper, we developed and validated an accurate network protector relay model and interfaced a commonly used network protector relay hardware with our real-time simulation system. Hardware-in-the-loop protection studies are performed to assess the impact of distributed energy resources and benchmark a mitigation strategy. Simulation results suggest that the network protector reverse trip and auto-reclose functions are negatively impacted by the high distributed energy resource penetration. To accommodate DER backfeed while remaining secure and reliable for faults on primary feeders, we recommend options for a rate-of-change-based blocking scheme and a protection setting change. Finally, future mitigation ideas and standard revisions are discussed.