The number of high voltage direct current (HVDC) links continue to increase over the years, most of them, for offshore applications or bulk power transmission over long distances. The present paper evaluates the possible development of a direct current (dc) grid in Europe given the present, and future, HVDC links. Eight potential cases for the interconnection between close links are suggested as starting scenario for a multiterminal network. The need of a dc-dc converter and its special requirements are evaluated in function of suggested interconnections. As an example, a case study is chosen to evaluate the behavior of an interconnection between line commutated converter (LCC) and voltage source converter (VSC) link using a front-to-front (F2F) isolated converter.

Keywords— HVDC offshore grid, dc-dc converter, HVDC transmission, Modular Multilevel Converter (MMC), Line Commutated converter (LCC).

Daniel Gómez A., Piotr Dworakowski, Juan D. Páez, Oriol Gomis-Bellmunt, Marc Cheah-Mane, Florent Morel