Planning the optimal number and placement of embedded VSC-HVDC links in the German AC transmission grid

Inhalt:
The paper presents a three-step methodology for planning the optimal number and placement of embedded VSC HVDC links. In step one homogeneous expansion plans without congestions are created. These plans only include either AC or DC reinforcements. In step two a series of heterogeneous expansion plans is created. All plans of a series have a different proportion of AC and DC reinforcements. In step three the total costs of all plans are compared to identify the optimal plan. The approach is tested on a 2022 central European transmission network model for a 2050 scenario. 4 GW and 6 GW embedded VSC HVDC cable links are used and a sensitivity analyses with DC overhead lines is conducted. The results show that DC solutions are competitive to AC network reinforcements.