The report is devoted to the problem of increasing the reliability and manoeuvrability of the CCGT when it operates in power control modes of the power system. The generalized results of research on improving the reliability and expanding the adjustment range of the PGU-450 based on the use of bypass steam distribution, reducing the duration of start-up operations and increasing the loading speed of the steam turbine and CCGT in general in the modes of CCGT power reserve during the night load gap by transferring the CCGT steam turbine to the motor mode when the CCGT operates in the condensation mode or in the heating mode according to the GTU-CHP scheme are presented. Additional advantages of the motor mode are noted: improved reliability of the steam turbine due to the elimination of cyclic temperature fluctuations of its steam inlet valves and vibrations in the last stages of the low-pressure cylinder and the possibility of operating th