Ambient winds may deteriorate the thermo-flow performances of air-cooled condenser (ACC) in power plants, so it is of benefit to the energy efficient operation of ACC to propose measures against adverse wind effects. In this work, the air deflectors installed under the fan platform of ACCs are proposed on the basis of a 2 x 300 MW direct dry cooling power plant. The flow and temperature fields of cooling air are obtained and analyzed for the air deflectors with various geometric parameters. The air mass flow rate and turbine back pressure are computed and compared with the original ACCs. The results show that the thermo-flow performances of ACCs are significantly influenced by the width, pitch, inclination angle and number of air deflectors, and get improved due to the restrained reverse flows in windward condenser cells. In most cases, the wide and more air deflectors are preferred, but the moderate pitch is recommended to improve the ACC performances. Moreover, the 45 degrees inclination of air deflectors is superior to others in restraining the adverse wind effects. (C) 2017 Elsevier Ltd. All rights reserved.