Impact of Resistive-Type Superconducting Fault Current Limiter on Dynamics of VSC-MTDC Systems

Multi-terminal flexible DC transmission technology is considered as an important means to realize the interconnection between two remote area power grids. Due to the difficulty of clearing the DC side faults in multi-terminal flexible DC transmission systems, a scheme using resistive-type superconducting fault current limiter (RSFCL) to limit the DC-side fault current level is proposed. The effects of RSFCL on the dynamics of multi-terminal flexible DC transmission systems under different power grid strengths are analyzed based on the PSCAD / EMTDC simulation platform. It is found that the presented RSFCL can improve the dynamic response of the system during the fault events, enhance the synchronizing stability and alleviate the adverse impact caused by phase-lock loop (PLL) when connected with weak AC power networks.