Twin-shaft gas turbine

Abstract

A twin-shaft gas turbine, which has a gas generator including a compressor, a combustor, and a high-pressure turbine, is configured to make a first control mode and a second control mode selectively useable for control of the gas generator. In addition, in the first control mode, an IGV angle in the compressor is controlled in accordance with a corrected shaft rotation speed of the gas generator, and in the second control mode, the IGV angle is controlled to maintain a constant gas generator shaft rotation speed. Furthermore, the first control mode is used to start, to stop, and to operate the turbine under fixed or lower load conditions, and that the second control mode is used under operational states other than those to which the first control mode is applied.

1 . A twin-shaft gas turbine comprising:
 a compressor;   an inlet guide vane for changing an air inlet rate of the compressor;   a combustor for burning a fuel mixedly with the compressed air supplied from the compressor;   a high-pressure turbine driven by the combustion gases generated at the combustor; and   a low-pressure turbine which the combustion gases that drove the high-pressure turbine are supplied to,   wherein the gas turbine further comprises;   a first control mode to which lines of operation of the inlet guide vane are changed corresponding to atmospheric temperature of the high-pressure turbine which rotates at low speed,   a second control mode in which the opening angle of the inlet guide vane is controlled to maintain a constant rotation speed of the high-pressure turbine which rotates at high speed.   
     
     
         2 . The twin-shaft gas turbine according to  claim 1 , wherein the gas turbine further comprises;
 a third control mode for maintaining a constant angle of the inlet guide vane of the compressor independently of a rotation speed of the high-speed turbine is executed during a mode change between the first control mode and the second control mode.   
     
     
         3 . A method for controlling operation of a twin-shaft gas turbine, the gas turbine comprising:
 a compressor;   an inlet guide vane for changing an air inlet rate of the compressor;   a combustor for burning a fuel mixedly with the compressed air supplied from the compressor;   a high-pressure turbine driven by the combustion gases generated at the combustor; and   a low-pressure turbine which the combustion gases that drove the high-pressure turbine are supplied to;   wherein the method includes,   controlling the opening angle of the inlet guide vane on the basis of changed lines of operation of the inlet guide vane corresponding to atmospheric temperature of the high-pressure turbine which rotates at low speed,   controlling the opening angle of the inlet guide vane to maintain a constant rotation speed of the high-pressure turbine which rotates at high speed.   
     
     
         4 . The method for controlling operation of a twin-shaft gas turbine according to  claim 3 , wherein the method for controlling operation of a twin-shaft gas turbine further comprises;
 controlling the opening angle of the inlet guide vane to maintain a constant angel independently of a rotation speed of the high-pressure turbine is executed during a change of the rotational state of a high pressure turbine between a low-speed rotational state and a high-speed rotational state.