Patent ID: 7634914

Claim:
A control method for a gas turbine comprising: controlling opening of at least one fuel valve to maintain a temperature (Tfire) of gas at an inlet of the gas turbine and a fuel-air ratio (F/A) within predetermined limits by: calculating a set point exhaust temperature (TX) as a sum of a reference temperature (TXbase) and a plurality of correction values each of which are associated with a different operating parameter; wherein corrections values are calculated by computer simulations of the gas turbine, the simulations being conducted by specifying attainment of one of: a maximum of the set point exhaust temperature (TXmaxTfire) and a maximum of the fuel-air ratio (F/A), for each condition differing from a reference condition; further wherein said plurality of correction values includes four corrections values and wherein said step of calculating further comprises calculating: TX=TXbase+DeltaTX_Dpin+DeltaTX_Dpout+DeltaTX_Hum+DeltaTX_PCNLP where: TX is said set point exhaust temperature: DeltaTX_Dpin is a correction value for the set point exhaust temperature (TX) associated with a variation of pressure drops in intake pipes with respect to a nominal value of 0 mmH2O, DeltaTX_Dpout is a correction value for the set point exhaust temperature (TX) associated with a variation of pressure drops in exhaust pipes with respect to a nominal value of 0 mmH2O, DeltaTX_Hum is a correction value for the set point exhaust temperature (TX) associated with a variation of a relative humidity of air with respect to a nominal value of 60%, and DeltaTX_PCNLP is a correction value for the set point exhaust temperature (TX) associated with a variation of a speed of a low pressure shaft with respect to a nominal value of 100%.