Abstract: A method for starting up a combined cycle plant in which the following steps are executed: a gas turbine start-up step of increasing an output of a gas turbine to a rated output, a steam admission step of starting steam supply to a steam turbine when a temperature of the steam from a waste heat recovery boiler reaches or exceeds a predetermined temperature, and an ST generator output control step of controlling a flow rate of steam flowing into the steam turbine after a generator is synchronized so that an output of the generator increases according to a target output change pattern. In the ST generator output control step, when a thermal stress reaches or exceeds a predetermined first thermal stress, the flow rate of the steam is controlled so that the change in the generator output is smaller than a change indicated by the target output change pattern.

Abstract: A method for starting up a combined cycle plant in which the following steps are executed: a gas turbine start-up step of increasing an output of a gas turbine to a rated output, a steam admission step of starting steam supply to a steam turbine when a temperature of the steam from a waste heat recovery boiler reaches or exceeds a predetermined temperature, and an ST generator output control step of controlling a flow rate of steam flowing into the steam turbine after a generator is synchronized so that an output of the generator increases according to a target output change pattern. In the ST generator output control step, when a thermal stress reaches or exceeds a predetermined first thermal stress, the flow rate of the steam is controlled so that the change in the generator output is smaller than a change indicated by the target output change pattern.