The AC/DC coupling effect of multiple feeds into the power grid leads to the transmission of faults between regions

the power flow transfer in each section is intensified

and the voltage impact degree surges after the fault

which has a serious impact on the safe and stable operation of the power grid. Because of the decoupling effect of flexible DC and the ability of mutual supply of regulated power

this paper proposes a flexible DC landing point optimization method for fault transmission blocking in the interval of a multi-feed power grid. Firstly

the blockable steps were analyzed to determine the change in each electrical quantity in the fault transmission process of the multi-feed power grid. Secondly

the degree of impact of DC operation in each region under the influence of single AC and AC/DC superposition was studied.According to the proportion of DC coupling in the AC/DC superposition

the proportion factor of DC coupling degree was proposed to narrow the selection range of flexible vertical landing point schemes between different regions. Then

a multi-DC decoupling factor to measure the blocking effect of interval DC coupling was proposed

and a screening index to measure the degree of power flow optimization of the landing scheme in each area was proposed to realize the optimization of flexible DC landing points. Finally

based on a province's actual power grid model with typical multi-DC feeds

the simulation analysis is carried out to verify that the proposed method can effectively block the fault transmission problem between regions.