2-shaft gas turbine, and the control method of opening degree of inlet guide vane of the gas turbine

A control method of an inlet guide vane of a 2-shaft gas turbine including a gas generator that is configured of a compressor that has inlet guide vanes on an air intake side and compresses inflow air, a combustor that generates combustion gas by burning air that is compressed by the compressor and fuel, and a high pressure turbine driven by the combustion gas generated by the combustor;

• and a low pressure turbine that is driven by gas discharged from the high pressure turbine, in which a high pressure turbine shaft that connects the compressor to the high pressure turbine, and a low pressure turbine shaft that connects the low pressure turbine to a load are separated shafts, and an inflow air amount to the compressor is adjusted by controlling an opening degree of the inlet guide vane,
• wherein, in the control of the opening degree of the inlet guide vane,
• as a unit that controls the opening degree of the inlet guide vane, a first control unit;
• a control status confirmation unit, and a low atmospheric temperature correction unit are included, and
• in the first control unit, the opening degree of the inlet guide vane is adjusted so as to keep an actual speed of the high pressure turbine shaft constant during a high speed rotation of the high pressure turbine shaft;
• in the control status confirmation unit, the actual speed that is kept constant by the first control unit and the opening degree of the inlet guide vane are confirmed;
• and in the low atmospheric temperature correction unit, the opening degree of the inlet guide vane is controlled so as to reduce the actual speed that is kept constant by the first control unit in a case where the actual speed that is kept constant by the first control unit input into the control status confirmation unit is equal to or greater than a predetermined threshold value N0, the opening degree of the inlet guide vane is equal to or greater than a predetermined threshold value ξ0, and an atmospheric temperature is equal to or less than a predetermined threshold value Ta0.