Predicting the output powers of gas turbine and steam turbine distinctively in single-shaft combined cycle power plant(CCPP) is one of the most significant problems for operating condition monitoring and performance analysis for the CCPP. Based on the theoretical principles of single-shaft combined cycle units

a mathematical method with practical implement and strong versatility was proposed in this paper to calculate the power output of gas turbine and steam turbine distinctively. The results show that

compared with the heat-balance design data of a single-shaft CCPP with an F-class gas turbine and a triple-pressure steam-reheat condensing steam turbine

the maximum relative deviation between calculation results by the proposed method and design data is 1.6% for steam turbine power output and -1.42% for gas turbine power output

which indicates that the proposed numerical method has good calculation accuracy and can provide reference for engineering applications.