Abstract: Starting from the DC transmission system model of wind power, this paper explores the transient voltage characteristics of the power grid and wind farm,the mechanism of continuous commutation failure,and proposes the overvoltage suppression measures from the perspective of reactive power compensation. A provincial wind power DC transmission system is used as examples for the simulation analysis,the impact characteristics of the wind farm,the transient voltage and the suppression measures of the transmission system under continuous commutation failure are studied especially,and the theoretical verification is carried out.