Short‐Circuit Protection for High‐voltage Converters

The modular multilevel converter (MMC) has become the most attractive converter topology for high‐voltage direct‐current (HVDC) transmission systems because of its modularity and scalability. Thus, one of the major challenges associated with MMC‐HVDC systems is the capability to handle DC‐side short‐circuit faults. This chapter discusses three short‐circuit protection schemes for the proposed multi‐terminal high‐voltage converters, according to the DC fault solutions of the MMC‐HVDC system. It introduces a novel modular DC circuit breaker (CB) which makes use of the structure of the switching arm. The chapter analyses the several typical kinds of sub‐module (SM) with DC fault‐handling capability which can replace HBSMs in the multi‐terminal high‐voltage converters. It proposes the feasible architectures of a hybrid multi‐terminal high‐voltage converter with short‐circuit protection feature.