Assessment of Secondary Frequency Control and Synthetic Inertia Contribution of RES to Sicily's Frequency Stability

Load Frequency Control (LFC) is an important mechanism for maintaining system frequency near to its nominal value after disturbances, as deviations from nominal value can adversely affect both system stability and power quality. In a previous work, the impact of the contribution of Renewable Energy Sources (RES) control approaches, specifically droop-based regulation enabling Fast Frequency Response (FFR), was assessed in combination with the contribution of High Voltage Direct Current (HVDC) droop control of the West Tyrrhenian Link. This study extends the work by evaluating the effectiveness of FFR with Synthetic Inertia (SI) support provided by RES and assesses the impact of the implementation of secondary frequency regulation in RES power plants under the same disturbance conditions. The results show that SI improves the system's dynamic frequency response, while the coordinated implementation of SI and secondary control at the RES level effectively restores system balance and significantly enhances overall frequency stability in a high-RES, low-inertia environment.