Method and Apparatus for Controlling Gas Turbine Combustor

Abstract

An apparatus for controlling a gas turbine combustor having a diffusion combustion burner and a premix combustion burner comprising: a rotating speed detector for detecting a rotating speed of gas turbine, a recorder for recording the detected value of the rotating speed of gas turbine detected by the rotating speed detector, an arithmetic unit for calculating a change with time of the rotating speed of gas turbine in accordance with details of the detected value of the rotating speed of gas turbine recorded in the recorder, and a fuel control unit for judging a starting situation of reduction in the rotating speed of gas turbine on the basis of the change with time of the rotating speed of gas turbine calculated by the arithmetic unit and controlling respectively a fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner.

What is claimed is: 
     
         1 . An apparatus for controlling a gas turbine combustor having a diffusion combustion burner and a premix combustion burner comprising:
 a rotating speed detector for detecting a rotating speed of gas turbine, a recorder for recording the detected value of the rotating speed of gas turbine detected by the rotating speed detector, an arithmetic unit for calculating a change with time of the rotating speed of gas turbine in accordance with details of the detected value of the rotating speed of gas turbine recorded in the recorder, and   a fuel control unit for judging a starting situation of reduction in the rotating speed of gas turbine on the basis of the change with time of the rotating speed of gas turbine calculated by the arithmetic unit and controlling respectively a fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner.   
     
     
         2 . The apparatus for controlling a gas turbine combustor according to  claim 1 , wherein:
 the arithmetic unit for calculating the change with time of the rotating speed of gas turbine is structured so as to detect a situation that the rotating speed of gas turbine increased at the time of a load dump of the gas turbine starts to reduce by calculation of the change with time of the rotating speed of gas turbine, output an operation signal for controlling the fuel flow rate to the fuel control unit, switch, by the fuel control unit, a combustion state of the gas turbine combustor from independent diffusion combustion by the diffusion combustion burner to mixed combustion of diffusion combustion and premix combustion by the diffusion combustion burner and the premix combustion burner, and control respectively the fuel flow rate for the diffusion combustion burner fed to the diffusion combustion burner and the fuel flow rate for the premix combustion fed to the premix combustion burner.   
     
     
         3 . An apparatus for controlling a gas turbine combustor having a diffusion combustion burner and a premix combustion burner comprising:
 a detector for detecting a rotating speed of gas turbine, a recorder for recording the detected value of the rotating speed of gas turbine detected by the rotating speed detector, an arithmetic unit for calculating a change with time of the rotating speed of gas turbine in accordance with details of the detected value of the rotating speed of gas turbine recorded in the recorder, a bleed valve opening angle detector for detecting an opening angle of a compressor bleed valve installed in a compressor, a logic circuit for checking a value of the change with time of the rotating speed of gas turbine calculated by the arithmetic unit and an opening angle signal of the bleed valve detected by the bleed valve opening angle detector, and a fuel control unit for respectively controlling a fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner so as to switch a combustion state of the gas turbine combustor from independent diffusion combustion by the diffusion combustion burner to mixed combustion of diffusion combustion and premix combustion by the diffusion combustion burner and the premix combustion burner on the basis of check results by the logic circuit.   
     
     
         4 . The apparatus for controlling a gas turbine combustor according to  claim 3 , wherein the control unit of the gas turbine combustor is structured so that:
 when it is detected by the checking by the logic circuit that the rotating speed of gas turbine increased from a rated rotating speed at the time of a load dump of the gas turbine starts to reduce and the opening angle of the bleed valve installed in the compressor is totally closed, the logic circuit transmits an instruction signal to the fuel control unit, switches the gas turbine combustor from the independent diffusion combustion by the diffusion combustion burner to the mixed combustion of the diffusion combustion and the premix combustion by the diffusion combustion burner and the premix combustion burner, and respectively controls the fuel flow rate for the diffusion combustion burner fed to the diffusion combustion burner and the fuel flow rate for the premix combustion fed to the premix combustion burner.   
     
     
         5 . An apparatus for controlling a gas turbine combustor having a diffusion combustion burner and a premix combustion burner comprising:
 a fuel control unit for respectively controlling a fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner so as to switch a combustion state of the gas turbine combustor from independent diffusion combustion by the diffusion combustion burner to mixed combustion of diffusion combustion and premix combustion by the diffusion combustion burner and the premix combustion burner on the basis of a signal transmitted from a timer circuit, which is installed to transmit a signal for controlling the fuel control unit after a predetermined period of time after receipt of a load dump signal of gas turbine, after a predetermined period of time.   
     
     
         6 . The apparatus for controlling a gas turbine combustor according to  claim 1 , wherein:
 the control unit of the gas turbine combustor is installed in a biaxial gas turbine unit.   
     
     
         7 . A method for controlling a gas turbine combustor including a diffusion combustion burner and a premix combustion burner, comprising the steps of:
 detecting a rotating speed of gas turbine, recording the detected value of the rotating speed of gas turbine, calculating a change with time of the rotating speed of gas turbine in accordance with details of the recorded detected value of the rotating speed of gas turbine, judging a starting situation of reduction in the rotating speed of gas turbine on the basis of the calculated change with time of the rotating speed of gas turbine, and regulating a fuel flow rate fed to the gas turbine combustor controls respectively a fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner.   
     
     
         8 . The method for controlling a gas turbine combustor according to  claim 7 , wherein:
 the calculating a change with time of the rotating speed of gas turbine is performed in a situation that the rotating speed of gas turbine increased at the time of a load dump of the gas turbine starts to reduce by calculation of a trend of the change with time in which the rotating speed of gas turbine is recorded and when it is judged that the situation that the rotating speed of gas turbine starts to reduce occurs,   outputting an operation signal for controlling the fuel flow rate to the fuel control unit,   regulating the fuel flow rate fed to the gas turbine combustor switches a combustion state of the gas turbine combustor from independent diffusion combustion by the diffusion combustion burner to mixed combustion of the diffusion combustion and the premix combustion by the diffusion combustion burner and the premix combustion burner, and   respectively controlling the fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner and the fuel flow rate for the premix combustion to be fed to the premix combustion burner.   
     
     
         9 . A method for controlling a gas turbine combustor including a diffusion combustion burner and a premix combustion burner, comprising the steps of:
 detecting a rotating speed of a gas turbine, recording the detected value of the rotating speed of gas turbine, calculating a change with time of the rotating speed of gas turbine in accordance with details of the recorded detected value of the rotating speed of gas turbine, detecting an opening angle of a compressor bleed valve installed in a compressor, and regulating a fuel flow rate fed to the gas turbine combustor on the basis of check results of a calculated value of the change with time of the rotating speed of gas turbine and a detected opening angle signal of the bleed valve respectively controls a fuel flow rate for the diffusion combustion burner to be to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner so as to switch a combustion state of the gas turbine combustor from independent diffusion combustion by the diffusion combustion burner to mixed combustion of the diffusion combustion and the premix combustion by the diffusion combustion burner and the premix combustion burner.   
     
     
         10 . The method for controlling a gas turbine combustor according to  claim 9 , wherein:
 when it is detected by the checking that the rotating speed of gas turbine increased from a rated rotating speed at the time of a load dump of the gas turbine starts to reduce and the opening angle of the bleed valve installed in the compressor is totally closed, the fuel control unit for regulating the fuel flow rate fed to the gas turbine combustor switches the gas turbine combustor from the independent diffusion combustion by the diffusion combustion burner to the mixed combustion of the diffusion combustion and the premix combustion by the diffusion combustion burner and the premix combustion burner and controls respectively the fuel flow rate for the diffusion combustion burner fed to the diffusion combustion burner and the fuel flow rate for the premix combustion fed to the premix combustion burner.   
     
     
         11 . A method for controlling a gas turbine combustor having a diffusion combustion burner and a premix combustion burner, comprising the steps of:
 controlling a fuel flow rate for the diffusion combustion burner to be fed to the diffusion combustion burner installed in the gas turbine combustor and a fuel flow rate for the premix combustion to be fed to the premix combustion burner respectively so as to switch a combustion state of the gas turbine combustor from independent diffusion combustion by the diffusion combustion burner to mixed combustion of the diffusion combustion and the premix combustion by the diffusion combustion burner and the premix combustion burner on the basis of a signal transmitted from a timer circuit, which is installed to transmit a signal for controlling the fuel control unit after a predetermined period of time after receipt of a load dump signal of gas turbine, after a predetermined period of time.   
     
     
         12 . The method for controlling a gas turbine combustor according to  claim 7 , wherein:
 the control method of gas turbine combustor is used for a control method of a gas turbine combustor of a biaxial gas turbine unit.