The report is devoted to the problem of creating a digital model of an energy facility in relation to the PGU-450T power unit in the absence of the possibility of conducting field experiments to obtain initial information. Under these conditions, it is proposed to use a computer simulator of the object under study. The main provisions of checking the adequacy and validity of the simulator to a real object for static and dynamic processes are outlined, examples of such verification are given. The application of a specific simulator of JSC "Simulators for power plants" for modeling the parameters of the equipment of the CCGT and the CCGT as a whole during the operation of the CCGT at reduced loads is justified. The results of the numerical experiments carried out on the simulator were used to create a digital model of the PGU-450T in the form of a data library and regression equations in the form of dependencies of the main indicators of gas turbines, waste heat boilers, steam turbines and CCGT as a whole on the power of the CCGT, outdoor air temperature, fuel consumption for various modes of gas and steam turbines. The effectiveness of the use of the digital model of the PGU-450T (Russian model of CCGT) is illustrated by the example of solving the practical problem of optimal distribution of the total load of the GTU between gas turbines when the CCGT operates at reduced loads.