Patent ID: 6880324

Claim:
A combined cycle plant comprising: a gas turbine fuel control valve which controls supply of first fuel; a duct burner fuel control valve which controls supply of second fuel; a generator; a gas turbine which drives said generator by burning said first fuel supplied through said gas turbine fuel control valve; a boiler which has a duct burner, heats gas exhausted from said gas turbine by burning said second fuel supplied through said duct burner fuel control valve by said duct burner, and heats water with said heated exhausted gas to generate steam; a steam turbine which is driven with said steam to drive said generator; and a controller which controls said gas turbine fuel control valve and said duct burner fuel control valve, wherein said controller controls an open degree of said gas turbine fuel control valve such that rapid increase of the supply of said first fuel is restrained when the supply of said second fuel to said duct burner is stopped.