Hierarchical Primary–Secondary Control of HVDC Grids: Challenges of Droop Control Schemes in Ensuring Safe Operation under Large-Scale Renewable Integration
Multi-terminal HVDC (MTDC) has been considered a cornerstone for integrating large-scale renewables. A key aspect of operating these MTDC networks is the hierarchical design of primary and secondary HVDC grid controllers, which traditionally assumes a clear temporal separation between fast acting primary control and slower, systemwide secondary controllers.