COMBINED POWER GENERATION SYSTEM AND OPERATION CONTROL METHOD THEREOF

A combined power generation system includes a gas turbine including a compressor configured to compress air, a combustor configured to mix the compressed air from the compressor and fuel and combust a mixture of the compressed air and fuel, and a turbine section in which rotational power is obtained by combustion gases generated by the combustor. The system also includes a heat recovery steam generator (HRSG) in which steam is generated by heat of exhaust gases from the gas turbine, and a steam turbine driven by the steam generated by the HRSG, wherein the HRSG includes a plurality of heat exchangers provided to cool the compressed air by heat exchange between the compressed air and the exhaust gases.