The　performance　of　the　fan　array　in　the　air-cooled　steam　condensers　(ACSCs),　which　consumes　a　large　amount　of　the　power　from　the　generator,　always　affects　the　characteristics　of　the　whole　power　plant　under　the　effect　of　the　meteorological　conditions.　As　a　result,　it　is　significant　to　optimize　the　fan　mode　to　obtain　a　maximum　operation　efficiency　of　the　air-cooled　thermal　system.　In　the　paper,　a　2　x　600　MW　power　plant　is　modeled　to　investigate　the　influence　from　the　fan　rotating　speed　on　the　performance　of　the　fan　array　as　well　as　the　whole　air-cooled　power　plants.　It　is　found　that　the　promotion　of　the　fan　rotating　speed　of　the　windward　fans　improves　the　performance　of　the　fan　array　and　the　heat　transfer　characteristics　of　the　exchangers　in　the　air-cooled　steam　condenser,　and　the　beneficial　net　power　in　consideration　of　the　fan　consumption　is　also　raised　effectively　with　an　improved　thermal　efficiency　of　the　closed　Rankine　cycle.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.