Demonstration of Output Control Using a Renewable Flexible Interconnection Operation System in the Jeju Power System

In this paper, a renewable energy flexible interconnection operation procedure and system were applied to demonstrate output curtailment in the main transformer distribution network of the substation in Jeju. The proposed system forecasts photovoltaic (PV) and wind generation, as well as load demand, on a day-ahead (D-1) basis at 15-minute intervals, and determines the curtailment requirements for each generator by calculating the hosting capacity of the transformer through net load and voltage stability assessments. On the operating day (D-day), curtailment commands are issued to renewable generators, and real-time monitoring is conducted to verify execution against the planned schedule.<br/>The field demonstration, carried out from May 2–3, 2024, during a period of frequent reverse power flow, successfully reduced renewable generation to maintain reverse flow within the hosting capacity limit. The results confirm that the proposed system can effectively implement forecast-based curtailment strategies in actual grid operation, contributing to both enhanced renewable hosting capacity and improved grid stability. This result provides a technical foundation for expanding the flexible interconnection approach to other renewable-concentrated regions in Korea.