With　the　high　proportion　of　new　energy　access,　the　three-phase　imbalance　problem　of　power　grid　is　becoming　more　and　more　prominent,　and　it　is　urgent　to　analyze　the　three-phase　power　flow　algorithm　suitable　for　engineering.　The　traditional　three-phase　power　flow　algorithm　has　problems　such　as　strong　initial　value　dependence,　complex　model,　low　computational　efficiency　and　limited　applicable　scenarios.　The　holomorphic　embedding　method　is　a　new　analytical　method　for　solving　nonlinear　power　flow　equations,　which　has　the　advantages　of　independent　of　initial　values　and　constant　matrix　in　the　solution　process.　Therefore,　based　on　the　characteristics　of　the　three-phase　element　model　of　the　power　grid,　this　paper　first　uses　the　phase　sequence　transformation　matrix　to　construct　the　holomorphic　embedding　model　of　the　three-phase　power　flow.　Secondly,　based　on　the　principle　of　equal　power　series　coefficients,　the　recursive　relationship　of　model　coefficients　is　derived,　and　the　matrix　paradigm　technique　is　used　to　simplify　the　calculation　model.　Thirdly,　the　zero-sequence　constraint　equation　is　reconstructed　analytically,　and　the　matrix　row-column　replacement　technology　is　used　to　realize　the　efficient　solution　of　three-phase　power　flow　under　different　grounding　modes.　Finally,　the　proposed　method　has　been　verified　on　IEEE　33,　modified　IEEE　123　and　a　regional　power　grid　system　in　China,　demonstrating　its　the　advantages　of　high　efficiency,　reliable　convergence　and　independence　from　the　initial　value　of　calculation.　©　2024　Chin.Soc.for　Elec.Eng.