In order to reduce the power curtailment of renewable energy, it is essential to improve the dispatch-ability of thermal power generating unit, among which the dynamic characteristics of the cold end system under varying operating conditions are of significant and necessary. Taking the thermal power plants with indirect dry cooling systems as object, the unsteady models for the dynamic characteristics of cold end were established. The transient behavior under the changing natural crosswind or power load were obtained. Four cooling water adjusting strategies were proposed to compare the standard coal consumptions during operating condition varying. The results indicate that the back pressure and cooling water temperature can change slowly despite of the abruptly change of the natural wind speed and output power load. It takes the cold end longer time to reach another stable state when the natural crosswind speed changes to a bigger value or the output power load decreases in a slower rate. The difference of ambient temperature and natural crosswind speed hardly affects the dynamic behaviors of the cold end system. When the cooling water flow rate is adjusted in the proper way, at most 21.4% more standard coal could be saved during load decreasing processes. (C) 2019 Elsevier Ltd. All rights reserved.