Building 100 % inverter-based distributed restart zone to assist system restoration

A perfect combination of weather and a power system backed by battery-based energy storage enabled Ireland to break a renewable penetration record in February 2022, with 96 % of electricity demand covered by wind generation at its peak. In high renewable energy penetration scenarios seen worldwide, ensuring the resilience of power systems against major events has received increased attention. Supplementing traditional generation units with renewables and distributed energy resources (DER) in the energy mix to meet the load demand and net-zero emission goals has affected power system inertia, black-start readiness, service restoration, and operations. Maintaining adequate resources to retain black-start readiness in anticipation of widespread outages is becoming challenging. This study reviews the technical aspect of a 100 % inverter-based resources (IBR) based distributed restart zone (DRZ) to assist black-start. It investigates the feasibility of using a set of IBR control schemes to help restart a non-black start combined cycle unit by aggregated energy storage system and PV via transmission lines. Through assistance from power system operators, common operation practices are incorporated and simulated in a black start cranking path case study. Simulation results are reported and compared against the traditional practices based on hydropower. The results show that the IBR could supplement the traditional black-start resources. The functional requirements identified in this study would be useful for developing GFL and GFM inverter controls in the industry to enable black-start ancillary service by IBR.