Abstract:With the construction process of ultra - high voltage ( UHV) AC power grid and the completion of Jinsu,Fufeng and Xizhe HVDC transmission lines,Sichuan power grid will form a pattern of AC/DC hybrid power delivery. Aiming at the situation of power transfer after UHV DC blocking and combined with the construction process of UHV AC power grid,the AC sections which have a strong coupling relationship with UHV DC is analyzed,which provides guidance for the safe and stable operation of Sichuan power grid.