Analysis of Renewable Energy Curtailment Compensation Costs, Optimal ESS Capacity, and Seasonal Dynamic Line Rating (DLR) in a Synthetic Jeju Island Power Grid

With the rapid expansion of renewable energy in the Jeju region, managing surplus power and ensuring grid stability have become critical challenges. This paper proposes an integrated approach combining Energy Storage System (ESS) operation, HVDC reverse power flow, and Dynamic Line Rating (DLR) to address renewable energy curtailment issues. Using the IEEE 30-bus test case, a curtailment threshold analysis was conducted by integrating photovoltaic (PV) generation, and the optimal ESS capacity was derived to mitigate voltage violations and curtailment compensation costs. AC power flow analysis on a synthetic 4-bus Jeju grid verified that coordinated ESS and HVDC operation successfully stabilized bus voltage within the allowable range while enabling surplus power transmission to the mainland. Furthermore, seasonal DLR analysis demonstrated that winter conditions significantly expanded HVDC line capacity, reducing line utilization from an overloaded state to a stable level without additional infrastructure. These results confirm that the proposed integrated strategy of ESS optimization and DLR application can effectively minimize renewable energy curtailment and reduce associated compensation costs in island power systems such as Jeju.