With the rapid development of HVDC (high voltage direct current) in Jiangsu Power Grid,large amount of electric power would be integrated through HVDC in the future.It is found that fault of the AC power grid would affect the operation of HVDC through the bus voltage of the converter station,which may lead to commutation failure.However,electromechanical simulations,which are used for power system stability analysis nowadays,may not be able to accurately reflect the dynamic process.In this paper,by using BPA and PSModel,electromechanical simulations as well as electromechanical and electromagnetic hybrid simulations are performed to study the impact of Jiangsu Power Grid fault on the operation of HVDC,and the conclusions are supposed to be helpful for power system analysis.