Utilising dynamic capacity of VSC-HVDC systems for improved congestion management

The integration of remote renewable energy sources (RES) demands refurbishment of transmission grid infrastructures e.g., with VSC-HVDC technology in numerous countries. This paper explores the potential of using the dynamic capacity of VSC-HVDC systems for congestion management in transmission grids, aiming to reduce redispatch and RES curtailment. It is proposed to integrate the peculiarities of variable temporary active power capabilities of VSC-HVDC into hybrid AC/DC optimal power flow calculations. The concept is simulated for the planned German grid for 2030, with two study objectives considered: a sensitivity analysis and a realistic scenario with hourly calculated factors. The sensitivity analysis shows that the initial 10% dynamic capacity yields the greatest reduction in redispatch and RES curtailment. While benefits still rise at 20% and 30% dynamic capacities, the incremental impact diminishes. In the realistic scenario where dynamic capacity is assumed in only one of the HVDC systems, incorporating hourly calculated factors and a mandated cooling period, the results show a 2% reduction in redispatch and RES curtailment compared to the reference case without dynamic capacity for Germany for the year 2030. The paper concludes that using dynamic capacity could assist in managing congested transmission grids in the future. It is also stressed that the functionality is highly project-dependent and still in the conceptual phase.