An enhanced reverse blocking MMC with DC fault handling capability for HVDC applications

Abstract This paper presents an enhanced reverse blocking modular multilevel converter (ERBMMC) topology, which features with reverse blocking IGBT based submodules (RBSMs) and current limit modules (CLMs), in order to improve the DC fault handling capability for HVDC applications. Based on analysis of the configuration and fundamental operation principles, the DC pole-to-pole fault has been taken into consideration for further studying the DC fault handling mechanism and the key components parameter selection guideline of ERBMMC. To validate the feasibilities and effectiveness of proposed topology and fault theory, extensive simulation results are demonstrated. It is concluded that ERBMMC is able to effectively extinguish the fault current arc under DC fault condition. In addition, CLMs plays an important role in further accelerating fault current attenuation. What is more, ERBMMC adopts the original control and modulation strategies under the normal operation condition, thus it further reduces the complicity of industry design.