Headroom based Frequency and DC-Voltage Control for Large Disturbances in Multi-Terminal HVDC (MTDC) Grids

In the AC integrated Multi-terminal HVDC (AC-MTDC) grids, it is indispensable to regulate the DC-voltage and frequency for reliable and stable operation. For effective DC-voltage and frequency regulation, Headroom-based Adaptive Droop Control (HR-ADC) has been proposed in this paper. The HR-ADC changes the droop value adaptively based on the available headroom at Grid Side Voltage Source Converter (GSC), and available power at the Wind or Solar Farms while operating Renewable Source side VSC (RSC). This approach is robust and ensures system stable operation and reliability even during significant disturbances in the AC-MTDC grids. The proposed method is validated by considering two case studies in PSCAD/EMTDC simulation of the five terminal CIGRE Bipolar DC grid benchmark model integrated into two area power systems.