In MIDC system

safety and stability of whole AC power system might be impacted seriously by followed commutation failure. It is important to research on factors of this fault. In this paper

the mechanism of followed commutation failure in multi-infeed HVDC transmission system is analyzed according to the operation and structure of MIDC system firstly. Then

based on the analysis results

AC voltage fluctuation by commutation failure and coupling of multi-infeed transmission HVDC system is studied respectively as the impact factors of followed commutation failure. Finally

a multi-infeed HVDC transmission system model is established in PSCAD/EMTDC

and the process of followed commutation failure in MIDC system under typical operation condition is presented. Comprehensive simulation results show that followed commutation failure in MIDC system would be codetermined by AC fault

MIIF and MSCR.