S-blocking strategy is used to treat ground fault in convertor station of UHVDC. As the first step of the Sblocking strategy

phase-shift has a significant impact on the overvoltage caused by ground fault in the convertor station. In order to investigate the impact of phase-shift parameters on the ground fault induced overvoltage

the Xiangjiaba-Shanghai ±800 kV DC Power Transmission Project is taken as an example to analyze the overvoltage characteristics in the conditions of different phase-shift startup delay

speed and mode. The results show that the improved phase-shift startup delay has a more significant influence on the overvoltage caused by ground fault

and the existing phase-shift speed and mode for the project are suitable.