Fault response comparison of LCC–MMC hybrid topologies and conventional HVDC topology

摘要

The modular multilevel converter (MMC) can be used to upgrade conventional line commutated converter-based HVDC systems (LCC-HVDC), construct the hybrid topologies of LCC and MMC to acquire better fault responses. In this study, the mechanisms of three kinds of hybrid topologies for dc fault clearance are firstly analysed. Then the fault responses of the three hybrid topologies and the conventional LCC-HVDC topology are detailedly compared, including dc line fault and ac faults at both rectifier side and inverter side. The comparison helps demonstrate the degree of improvement when MMC is adopted to upgrade the conventional LCC-HVDC.