METHOD OF CONTROLLING GAS TURBINE AND METHOD OF SETTING FUEL-AIR RATIO OF GAS TURBINE

PROBLEM TO BE SOLVED: To provide a method of controlling a gas turbine and a method of setting a fuel-ari ratio of the gas turbine, in which a generation amount of NOx is reduced and stable combustion is achieved.SOLUTION: A fuel amount setting part 41 sets a fuel amount based on a load demand. A stable fuel-air ratio setting part 42 sets a stable fuel-air ratio based on the set fuel amount, an upper limit of a NOx generation amount, an upper limit of combustion-driven oscillation, a current NOx generation amount and current combustion-driven oscillation. A control valve drive part 43 adjusts an opening of a control valve for supplying fuel and air to a combustor 13 on the basis of the set fuel-air ratio. A NOx generation amount modelling part 45 replaces a model value which is obtained by modelling the NOx generation amount based on an operation amount and a state quantity of the gas turbine, as the current NOx generation amount.