Modelling Protection Concepts for Multi-terminal HVDC Systems for Congestion Management

DC protection schemes in steady‑state, optimization‑based congestion‑management simulations. Building on linear network sensitivities the approach embeds MTDC protection zones consistently into the (n‑1) security assessment. Fully selective schemes are mapped to single‑line contingencies, while partially and non‑selective schemes are modelled as multiple‑line outages using Generalized Line Outage Distribution Factors. The resulting constraints ensure that the remaining DC and AC grid assets respect their thermal limits, both in normal operation and under (n‑1) conditions. The methodology is applied to a 2045 scenario of the European interconnected system based on TYNDP 2022 and national grid development plans. A modified SuedLink project, configured as a radial MTDC system, serves as a case study to quantify the impact of protection schemes on congestion‑management costs, remedial‑action volumes, and MTDC utilization. The results show that, in the examined setting, the choice of protection scheme has only a minor impact on the evaluation criteria.