Commutation failure prediction control(CFPREV)is equipped to reduce the probability of commutation failure and the risk of continuous commutation failure

but when it acts

more reactive power is required from AC system

which will affect the commutation failure characteristics and the recovery process of the AC and DC interconnected system. The reactive support coupling influence of multi-infeed DC in the restorability and restore process of the HVDC system is analyzed

and then an optimization method of CFPREV startup threshold is proposed considering the influence of the support ability of dynamic reactive power compensation devices

to achieve coordinated recovery of the whole system and reduce the risk of continuous commutation failure and its power impact on AC system. The effectiveness of the proposed method is verified based on the actual multi-infeed DC power grid simulation.