a compressor having a compressor outlet;

a high-pressure gas turbine with a combustion chamber and power turbine, said combustion chamber having a combustion chamber intake;

a device for injecting water or water vapor into a working medium, said device comprising an external connection housing with a radial housing portion, an axial housing portion and a plurality of injection nozzles, said external connection housing having a bent portion located between said radial housing portion and said axial housing portion, said radial housing portion being connected to said compressor outlet, said axial housing portion being connected to said combustion chamber intake, said bent portion having an inner bent portion surface for changing a direction of flow from a radial flow in said radial housing portion to an axial flow in said axial housing portion, said inner bent portion surface defining a space having a contour that is substantially similar to a contour of said bent portion, said injection nozzles being arranged along said inner bent portion surface such that each of said injection nozzles has an opening facing in a direction of said space, wherein water or water vapor is injected into a flow of combustion air compressed by said compressor via said device.