Fault blocking converters for HVDC transmission: a transient behaviour comparison

Abstract

A thorough comparison of the transient behaviours of two state‐of‐the‐art converters suitable for HVDC transmission is presented. The alternate arm and mixed‐cell modular multilevel converter topologies both have DC fault blocking capability and are selected for the comparison. Converter performance is evaluated and compared under various transient conditions including charging sequence, unbalanced operation, and DC fault recovery. The study is conducted using high‐fidelity converter simulation models, integrating detailed controllers that reflect real‐scale projects. The main findings of the study assist in the selection of the most suitable converter, given specific performance specifications such as capacitor voltage ripple, cell capacitor requirements, and response during transient operation.