GAS TURBINE FOR POWER PLANT APPLICATIONS WITH PRE-HEATED FUEL GAS AND METHOD FOR OPERATING THIS GAS TURBINE

A gas turbine assembly for power plant application fed by pre-heated fuel gas; the gas turbine comprises: a compressor configured for compressing incoming air; a sequential combustor assembly configured for feeding at least a fuel in the compressed air and generating a hot gas flow; wherein the combustor assembly comprises in series a first combustion stage and a second combustion stage; a turbine configured to be driven by the hot gas for performing work on a rotor; a fuel source configured for suppling pre-heated fuel to a fuel gas distribution system comprising a first line for feeding the first combustion stage and a second line for feeding the second combustion stage; at least the second line being provided with at least a metal valve; between the metal valve and the second combustion stage a first duct being present where leakage fuel gas can accumulate; wherein the gas turbine moreover comprises a second duct configured for feeding cooled air into the first duct wherein the cooled air has a temperature lower than the auto ignition temperature of the fuel gas.