Introduction  In order to improve the operational flexibility of the gas turbine combined cycle unit, ensure better economic performance of the unit, and avoid the gas turbine working in the inefficient operation area, this paper analyzes and studies the inlet air cooling system of the gas turbine.

  Method  The performance change and its influencing factors and the efficiency sensitivity analysis of gas turbine combined cycle unit were studied according to the thermal balance simulation results of considering inlet air cooling or not, based on the GT-Pro/GT-Master software platform.

  Result  The analysis results show that the output and efficiency of the gas turbine are greatly improved after using the inlet cooling system, and the output of the combined cycle unit is also increased while the efficiency is slightly reduced.

  Conclusion  Therefore, for the combined cycle unit, if the unit is supposed to generate more power, the inlet air cooling system should be used; if the total annual output of the unit is fixed and the annual utilization hours are relatively small, the inlet air cooling system should not be used.