The coupling interaction of AC-DC and DC-DC in the multi-infeed HVDC receiving-end power grid is so manifest that the commutation failure of multi-infeed HVDC caused by AC power system fault has become the key constraint to the security and stability of the receiving-end power grid. However

during the power grid planning stage

for lack of actual parameters of HVDC project

the concerned departments are still using recommended simplified quasi-steady-state model by CIGRE to carry out the safety and stability simulation analysis. The characteristics of power impact caused by HVDC commutation failure seriously deviate from the actual situation. The influence of reactive power supporting capability to HVDC commutation failure recovery is considered in the near-field

and the non-commutation failure HVDC power perturbation caused by multi-infeed HVDC interaction is taken into account. An improved method for multi-infeed HVDC power grid to accurately simulate the power impact on AC power system is proposed. The simulation results of actual power grid verify the effectiveness of the method.