Abstract

As the integration of offshore wind farms increases in recent years, research on Multi-Terminal HVDC systems protection draws attention. This paper presents a DC grid protection design principle considering MMCs feature temporary blocking capability. The proposed sizing approach minimizes DC reactors and determines DC circuit breaker (DCCB) specifications. Sensitivity analysis for different DCCB operating times is performed and the case study with grid extension is also evaluated to investigate the impact of temporary blocking functionality on protection design. The results indicate this functionality reduces total DC reactors size, while DCCB current breaking capabilities might be increased. Moreover, planned grid expansion might be required to be tackled from the initial stage to avoid undersizing protection components.

Domagoj Hart, Alberto Bertinato, Pascal Torwelle, Heitor Farias de Barros

Presented at IET ACDC 2025