Theoretical Parameter Design Method of SFCL for Concurrent Commutation Failure Inhibition in SFCL-Segmented Multi-Infeed LCC-HVDC Systems

Earlier works have reported the emerging fault current limiter (FCL) segmentation technique to mitigate concurrent commutation failure (CF) under ac faults in multi-infeed LCC-HVDC systems. However, the FCL's parameter is determined by the electromagnetic transient (EMT) simulation based method, which will lead to enormous workload and long computation time. Moreover, the subsequent CF after ac faults clearance has been ignored. Thus, this paper proposes a theoretical parameter design method of superconducting FCL (SFCL) for concurrent CF inhibition in SFCL-segmented multi-infeed LCC-HVDC systems. Firstly, a comprehensive evaluation approach of CF performance is introduced considering not only the voltage depression and distortion induced concurrent CFs but also the subsequent CF. This can give a more comprehensive CF evaluation than earlier works since the subsequent CF is considered in this approach. Secondly, three SFCL's parameter related evaluation indices, which can assess the SFCL's impact on the abovementioned three types of CF, are proposed to develop the proposed method based on the comprehensive CF evaluation approach. Compared to the simulation based method, the proposed method is implemented more efficiently without EMT simulations, and more effectively with the subsequent CF considered. Finally, the simulations based on dual-infeed and tri-infeed LCC-HVDC systems validate the proposed method.