Gas turbine system and control method therefor

The present invention provides a gas turbine system and a method for controlling the same, the gas turbine system comprising: a gas turbine that includes a compressor which generates compressed air, a combustor which combusts fuel with the compressed air, and a turbine which is driven by combustion gas generated by combustion of the fuel in the combustor; a motor generator that can be driven by the turbine and that can provide rotation power to the gas turbine by electric power supplied from the outside of the gas turbine; a fuel flow rate determination device that determines a parameter setting value which is used to control the flow rate of fuel supplied to the combustor; and a fuel flow rate control device that controls, on the basis of the setting value, the flow rate of the fuel supplied to the combustor. In a reverse electric power operation mode in which the motor generator provides rotation power to the turbine, the fuel flow rate determination device determines the setting value so that the flow rate of the fuel is the lower limit value in the reverse electric power operation mode.