Patent ID: 7555890

Claim:
A combined cycle power plant comprising: a compressor; a combustor for combusting supplied fuel together with compressed air compressed by said compressor; a gas turbine driven by a combustion gas exhausted from said combustor; a heat recovery steam generator (HRSG) for recovering high temperature gas exhausted from said gas turbine; a steam turbine driven by steam obtained from said heat recovery steam generator; an exhaust gas duct, provided between said gas turbine and said heat recovery steam generator, comprising an HRSG inlet duct that introduces said exhaust gas into said heat recovery steam generator and a bypass stack that leads said exhaust gas outside; a damper provided in said exhaust gas duct and configured to control a ratio of an exhaust amount of said exhaust gas to said bypass stack and an introduction amount of said exhaust gas into said HRSG inlet duct by changing any of an angle and opening of said damper; a damper drive for changing any of the angle and opening of said damper so that an exhaust amount of said exhaust gas to said bypass stack decreases in increasing an introduction amount of said exhaust gas into said HRSG inlet ducts; a control device operatively connected with the damper drive to control the damper drive based on any of an output value and exhaust gas temperature of the gas turbine so as to selectively fully open the bypass stack and fully close the HRSG inlet duct upon start up of the combined cycle power plant, to decrease said exhaust amount of said exhaust gas to the bypass stack and increase said introduction amount of said exhaust gas to the HRSG inlet duct upon any of the output value and exhaust gas temperature of the gas turbine being a predetermined value, and to fully close the bypass stack and fully open the HRSG inlet duct; and a guide mechanism for preventing a vibration of said damper, said guide mechanism including a track between an inner face of a side wall of said exhaust gas duct and a side face of said damper and extending between the fully closed position for said bypass stack and the fully closed position for said HRSG inlet duct.