Flow ratio calculation device, control device provided with the same, gas turbine plant provided with said control device, flow ratio calculation method, and method for controlling the fuel system

Abstract

A flow ratio calculation device for use in a gas turbine (10), wherein the gas turbine (10) comprises a plurality of fuel systems, a compressor (11) configured to generate compressed air by compressing air, a combustion chamber (31) configured to generate a combustion gas by combusting fuels from the plurality of fuel systems in the compressed air, and a turbine (21) capable of being driven by the combustion gas, wherein the flow ratio calculation device is configured to calculate a flow volume ratio of the fuels flowing in the plurality of fuel systems, and comprises: a flow volume ratio calculating device (140) configured to receive a value of a first parameter among a plurality of parameters that can express a combustion state in the combustion chamber (31) and to determine the flow volume ratio based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio; a correction value calculating device (142p) configured to determine a correction value of the flow volume ratio at a time when a load of the gas turbine (10) changes; a fluctuation sensor (144) configured to detect a fluctuation of a load-correlated value, which is a value that changes in correlation with changes in the load of the gas turbine (10) or which is a value of the load; and a correction device (151) configured to correct, after detecting a fluctuation in the load-correlated value by the fluctuation sensor (144), the flow volume ratio determined by the flow volume ratio calculation device (140) with the correction value determined by the correction value calculation device (142p), wherein the correction value calculation device (142p) is configured to receive a value of a second parameter different from the first parameter among the plurality of parameters and to determine the correction value based on the received value of the second parameter using a predetermined relationship between the second parameter and the correction value, wherein the correction value calculation device (142p) comprises a rise-time correction value calculation device (143pa) configured to determine a correction value based on the value of the second parameter when the load-correlated value increases by using a predetermined rise-time relationship between the second parameter and the correction value at a time when the load-correlated value increases, and a fall-time correction value calculation device (143pb) configured to determine a correction value based on the value of the second parameter when the load-correlated value decreases by using a predetermined fall-time relationship between the second parameter and the correction value at a time when the load-correlated value decreases; and wherein the correction device (151) is configured to correct the flow volume ratio determined by the flow volume ratio calculation device (140) with the correction value determined by the rise-time correction value calculation device (143pa) after the fluctuation sensor (144) detects an increase in the load-correlated value, and to correct the flow volume ratio determined by the flow volume ratio calculation device (140) with the correction value determined by the fall-time correction value calculation device (143pb) after the fluctuation sensor (144) detects a fall in the load-correlated value.

Description

The present invention relates to a technology for calculating a flow volume ratio of each of fuels supplied to a combustion chamber of a plurality of fuel systems.A gas turbine includes a compressor that compresses air, a combustor that generates a combustion gas by burning a fuel in the air compressed by the compressor, and a turbine that is driven by the combustion gas. Some combustors have an ignition burner for diffusion combustion of the fuel and a main burner for premixed combustion of the fuel. With such a combustion chamber, a ratio of the flow volume of the fuels supplied to the respective burners must be handled.According to the technology disclosed in JP 2012-077 662 A, for example, a flow volume ratio of fuels supplied to the respective burners is determined in accordance with a value indicated by a combustion load command that is the dimensionless temperature of an inlet of a turbine into which combustion gas flows from the combustion chamber. Further, this technology suppresses combustion fluctuation that may occur during return operations, which are operations to quickly reduce the load by changing the fuel flow volume ratio determined in accordance with the combustion load command value during the return operations.JP 2004-108 315 A discloses a flow ratio calculation device which can calculate a flow volume ratio of fuel (fuel supply ratio) between a diffusion combustion chamber and a premixing combustion chamber. The flow ratio calculating device includes a flow volume ratio calculating device, a correction value calculating device for calculating a correction value, and a correcting device that corrects the flow volume ratio depending on a correction value.The technology disclosed in JP 2012-077 662 A can suppress combustion fluctuation during return operations. However, it is also desirable to combust the fuel in the combustor in a stable manner in cases such as when the load is reduced outside the recirculation operations or vice versa when the load is increased.In view of the foregoing, an object of the present invention is to provide a technology that can improve combustion stability in a combustion chamber during various load changes.To achieve the above object, there are provided a flow ratio calculating apparatus having the features of claim 1, 3 or 6, a control apparatus having the features of claim 11, a gas turbine plant having the features of claim 14, and a flow ratio calculating method having the features of claim 15 or 17.The flow ratio calculation device according to the present invention is used in a gas turbine, the gas turbine including a plurality of fuel systems, a compressor that generates compressed air by compressing air, a combustor that generates a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine that is driven by the combustion gas. The flow ratio calculation device calculates a flow volume ratio of the fuels flowing in the plurality of fuel systems, and includes: a flow volume ratio calculation device that receives a value of a first parameter among a plurality of parameters that can express a combustion state in the combustor, and determines the flow volume ratio based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio; a correction value calculation device that determines a correction value of the flow volume ratio at a time when a load of the gas turbine changes; a variation sensor that detects a variation of the value correlated with the load, which is a value that changes in correlation with the changes in the load of the gas turbine, or which is a value of the load; A correction device that, after detecting a variation of the load correlated value from the variation sensor, corrects the flow volume ratio obtained by the flow volume ratio calculation device with the correction value obtained by the correction value calculation device.Combustion states in a combustion chamber are sometimes conditions that are not conducive to stable combustion in the combustion chamber when the value of a predetermined parameter among a plurality of parameters that can express a combustion state in the combustion chamber is a predetermined value. Under such non-feed conditions, when the total flow volume of the fuels supplied to the combustor is changed, or in other words, when the load is changed, there are cases where the stability of the combustion in the combustor is lost. Accordingly, with the flow ratio calculation device, the flow volume ratio obtained by the flow volume ratio calculation device is corrected with the correction value after detecting a variation of the load correlated value on the variation sensor side. Consequently, according to this flow ratio calculation device, the combustion stability in the combustion chamber at timings at which the value correlated with the load changes can be secured.In the above-described flow ratio calculation device, the correction value calculation device may receive a value of a second parameter different from the first parameter among the plurality of parameters, and determine the correction value based on the received value of the second parameter using a predetermined relationship between the second parameter and the correction value.In this case, the first parameter may be an input temperature correlated value that is a value that changes in correlation with changes in an input temperature of the combustion gas in the turbine or that is the input temperature. The second parameter may be one of an output of the gas turbine, a load percentage that is a percentage of a current load relative to an allowed maximum load from the gas turbine, a flow volume of all fuels supplied to the combustor from the plurality of fuel systems, and a flow volume of air drawn by the compressor.In each of the above-described flow ratio calculation devices in which the first parameter and the second parameter are received, the correction value calculation device may include a rise time correction value calculation device that determines a correction value based on the value of the second parameter when the value correlated with the load increases by using a predetermined rise time relationship between the second parameter and the correction value at a time when the value correlated with the load increases, and a fall time correction value calculation device that determines a correction value based on the value of the second parameter when the value correlated with the load decreases by using a predetermined fall time relationship between the second parameter and the correction value at a time when the value correlated with the load decreases. The correction device may correct the flow volume ratio number obtained by the flow volume ratio number calculation device with the correction value obtained by the rise time correction value calculation device after the variation sensor detects a rise of the load correlated value, and correct the flow volume ratio number obtained by the flow volume ratio number calculation device with the correction value obtained by the fall time correction value calculation device after the variation sensor detects a fall of the load correlated value.Further, in each of the above-described flow ratio calculation devices, the correction device may include a correction value setter that changes the correction value to be output so as to approach the correction value acquired by the correction value calculation device with the temporal change, and a flow volume ratio correction device that corrects the flow volume ratio acquired by the flow volume ratio calculation device with the correction value output by the correction value setter.Further, in each of the above-described flow ratio calculation devices, the combustion chamber may include an ignition burner and a main burner that inject fuels. The gas turbine may include, as the plurality of fuel systems, an ignition fuel system that supplies a fuel to the ignition burner and a main fuel system that supplies a fuel to the main burner. The flow volume ratio may include an ignition fuel ratio that is a ratio of a flow volume of the fuel supplied to the combustor from the ignition fuel system relative to a total flow volume of the fuels supplied to the combustor from the plurality of fuel systems.In each of the above-described flow ratio calculation devices in which the first parameter and the second parameter are received, the combustion chamber may include an ignition burner and a main burner that inject fuels. The gas turbine may include, as the plurality of fuel systems, an ignition fuel system that supplies a fuel to the ignition burner and a main fuel system that supplies a fuel to the main burner. The flow volume ratio may include an ignition fuel ratio that is a ratio of a flow volume of the fuel supplied to the combustor from the ignition fuel system relative to a total flow volume of the fuels supplied to the combustor from the plurality of fuel systems. The correction value calculation device may include a rise time correction value calculation device that determines a correction value based on the value of the second parameter when the value correlated with the load increases by using a predetermined rise time relationship between the second parameter and the correction value at a time when the value correlated with the load increases, and a fall time correction value calculation device that determines a correction value based on the value of the second parameter when the value correlated with the load decreases by using a predetermined fall time relationship between the second parameter and the correction value at a time when the value correlated with the load decreases. The correction device may correct the flow volume ratio number obtained by the flow volume ratio number calculation device with the correction value obtained by the rise time correction value calculation device after the variation sensor detects a rise of the load correlated value, and correct the flow volume ratio number obtained by the flow volume ratio number calculation device with the correction value obtained by the fall time correction value calculation device after the variation sensor detects a fall of the load correlated value. The falling time correction value calculation device may calculate a correction value having a larger value than the correction value obtained by the rising time correction value calculation device when the value of the second parameter has the same value.Further, in the flow ratio calculation device having the ignition ratio as the flow volume ratio, the correction value calculation device may calculate the correction value to increase the ignition fuel ratio calculated by the flow volume ratio calculation device.In this case, after the variation sensor detects a decrease in the load correlated value, the correction device may correct the ignition fuel ratio using the correction value obtained by the correction value calculation device such that the ignition fuel ratio calculated by the flow volume ratio calculation device increases.Further, in each of the above-described flow ratio calculation devices, the combustion chamber may include a burner that injects a fuel. The gas turbine may include, as the plurality of fuel systems, a burner fuel system that supplies a fuel to the burner and a cylinder head fuel system that supplies a fuel to the air supplied to the burner. The flow volume ratio may include a top hat fuel flow ratio that is a ratio of a flow volume of the fuel supplied to the combustion chamber from the top hat fuel system relative to a total flow volume of the fuels supplied to the combustion chamber from the plurality of fuel systems.In order to achieve the object described above, the control device according to the present invention includes:one of the above-described flow ratio calculation devices; a total flow volume calculation device that determines a total flow volume of the fuels supplied to the combustor from the plurality of fuel systems; a system flow volume calculation device that determines a fuel flow volume for each of the plurality of fuel systems using the total flow volume determined by the total flow volume calculation device and the flow volume ratio calculated by the flow ratio calculation device; and a valve control device that outputs a control signal to a fuel flow volume control valve provided in each of the plurality of fuel systems such that the fuel flow volume in each of the plurality of fuel systems becomes the fuel flow volume determined by the system flow volume calculation device.Here, the control device may further include a combustion load command generator that generates a combustion load command value that changes upon positive correlation with changes in the input temperature of the combustion gas in the turbine, and the flow volume ratio calculation device of the flow ratio calculation device may calculate a flow volume ratio based on the combustion load command value using the combustion load command value as a value of the first parameter.In addition, in each of the above-described control devices, the variation sensor can detect variation of the value correlated with the load with the total flow volume obtained by the total flow volume calculation device serving as the load correlated value.In order to achieve the object described above, the gas turbine plant according to the invention includes one of the control devices described above and the gas turbine.In order to achieve the object described above, a flow ratio calculation method according to the present invention is the flow ratio calculation method used in a gas turbine, the gas turbine including a plurality of fuel systems, a compressor that generates compressed air by compressing air, a combustor that generates a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine that is driven by the combustion gas. The flow volume ratio calculation method calculates a flow volume ratio of the fuels flowing in the plurality of fuel systems, and includes: a flow volume ratio calculation method for receiving a value of a first parameter among a plurality of parameters that can express a combustion state in the combustor, and determining the flow volume ratio based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio; a correction value calculation method for determining a correction value of the flow volume ratio at a time when a load of the gas turbine changes; a variation detection method for detecting variation of a load correlated value that is a value that changes in correlation with the changes in the load of the gas turbine or that is a value of the load; and after detecting variation of the load correlated value in the variation detection method, a correction method for correcting the flow volume ratio obtained in the flow volume ratio calculation method with the correction value obtained in the correction value calculation method.In the above-described flow ratio calculation method, in the correction value calculation step, a value of a second parameter different from the first parameter among the plurality of parameters may be received, and the correction value based on the received value of the second parameter may be obtained using a predetermined relationship between the second parameter and the correction value.In this case, the first parameter may be an input temperature correlated value that is a value that changes in correlation with changes in an input temperature of the combustion gas in the turbine or that is the input temperature; and the second parameter may be one of an output of the gas turbine, a load percentage that is a percentage of a current load relative to an allowed maximum load from the gas turbine, a flow volume of all fuels supplied to the combustor from the plurality of fuel systems, and a flow volume of air drawn by the compressor.In each of the above-described flow ratio calculation methods in which the first parameter and the second parameter are received, the correction value calculation method may include a rise time correction value calculation method for obtaining a correction value based on the value of the second parameter when the value correlated with the load rises by using a predetermined rise time relationship between the second parameter and the correction value of the flow volume ratio number at a time when the value correlated with the load rises, and a fall time correction value calculation method for obtaining a correction value based on the value of the second parameter when the value correlated with the load falls by using a predetermined fall time relationship between the second parameter and the correction value of the flow volume ratio number at a time, to which the value correlated with the load decreases is used. In the correction method, after an increase in the value correlated with the load is detected in the variation detection method, the flow volume ratio obtained in the flow volume ratio calculation method may be corrected with the correction value obtained in the rise time correction value calculation method, and after a decrease in the value correlated with the load is detected in the variation detection method, the flow volume ratio obtained in the flow volume ratio calculation method may be corrected with the correction value obtained in the fall time correction value calculation method.Further, in each of the above-described flow ratio calculation methods, the correction method may include a correction value setting method for changing the correction value to be output to be approximated to the correction value obtained in the correction value time-varying calculation method, and a flow volume ratio correction method for correcting the flow volume ratio obtained in the flow volume ratio calculation method using the correction value changed in the correction value setting method.In order to achieve the object described above, a fuel system control method according to the invention performs any one of the above-described flow ratio calculation methods, and further performs: a total flow volume calculation method for obtaining a total flow volume of the fuels supplied to the combustor from the plurality of fuel systems; a system flow volume calculation method for obtaining a fuel flow volume for each of the plurality of fuel systems using the total flow volume obtained in the total flow volume calculation method and the flow volume ratio calculated by the flow volume calculation method; and a valve control method for outputting a control signal to a flow volume control valve provided in each of the plurality of fuel systems such that the fuel flow volume in each of the plurality of fuel systems becomes the fuel flow volume obtained in the system flow volume calculation method.According to the present invention, combustion stability in combustion chambers at times of load drops and at times of load rises and at times of return operations can be improved. FIG. 1 is a plant diagram illustrating a gas turbine plant according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a combustor according to the embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating the main portion of the combustor according to the embodiment of the present invention. FIG. 4 is a functional block diagram illustrating a control device according to the embodiment of the present invention. FIG. 5 is a functional block diagram illustrating a combustion load command generator according to the embodiment of the present invention. FIG. 6 is a functional block diagram illustrating a load percentage computing device according to the embodiment of the present invention. FIG. 7 is a functional block diagram illustrating a fuel flow volume command generator according to the embodiment of the present invention. FIG. 8 is a functional block diagram illustrating a system flow volume computing device and a valve control device according to the embodiment of the present invention. FIG. 9 is a functional block diagram illustrating an ignition ratio calculator according to the embodiment of the present invention. FIG. 10 is a functional block diagram illustrating a hat calculator according to the embodiment of the present invention. FIG. 11 is a graph showing the relationship between a pre-correction ignition ratio (PL 0- ratio) and a combustion load command value CLCSO according to the embodiment of the present invention. FIG. 12 is a graph showing the relationship between a pre-correction ignition ratio (PL 0- ratio) and a load percentage %Load, and showing a relationship between ignition ratio correction values Ci and Cd and the load percentage %Load according to the embodiment of the present invention. FIG. 13 is a graph showing the relationship between a pre-correction hat ratio (TH 0- ratio) and the combustion load command value CLCSO according to the embodiment of the present invention. FIG. 14 is a graph showing the relationship between a pre-correction hat ratio (TH 0- ratio) and the load percentage %Load, and showing a relationship between hat ratio correction values Ci and Cd and the load percentage %Load according to the embodiment of the present invention. FIG. 15 is a flowchart illustrating the operations of the ignition ratio number calculator according to the embodiment of the present invention.An embodiment of aFlow ratio calculation apparatus; a control apparatus and a gas turbine plant including the control apparatus according to the present invention will be described below using the drawings.As illustrated in FIG. 1, the gas turbine plant according to the present embodiment includes a gas turbine 10 and a generator 29 that generates power by being driven by the gas turbine 10. The gas turbine 10 includes a compressor 11 that compresses air, a combustor 31 that generates a combustion gas by burning a fuel F in the air compressed by the compressor 11, and a turbine 21 that is driven by the high-temperature high-pressure combustion gas.The compressor 11 includes a compressor rotor 13 that rotates about an axis, a compressor housing 12 that covers the compressor rotor 13 while allowing the compressor rotor 13 to rotate, and an inlet guide blade (IGV) 14 provided at an inlet port of the compressor housing 12. The IGV 14 has a plurality of vanes 15 and a driver 16 that drives the plurality of vanes 15 and adjusts a flow volume of air drawn into the compressor housing 12.The turbine 21 includes a turbine rotor 23 rotated around the axis by the combustion gas from the combustor 31, and a turbine casing 22 covering the turbine rotor 23 while allowing the turbine rotor 23 to rotate. The turbine rotor 23 and the compressor rotor 13 rotate about the same axis and are connected together to form a gas turbine rotor 28. A rotor of the generator 29 is connected to this gas turbine rotor 28.As described in FIG. 2, the combustor 31 includes: an outer cylinder 32 attached to the turbine casing 22; a combustion liner (or transition piece) 33 that is disposed in the turbine casing 22 and that supplies the combustion gas to a combustion gas flow passage of the turbine 21; and a fuel supply unit 41 that supplies the fuel and air to the inside of the combustion liner 33.As illustrated in FIGS. 2 and 3, the fuel supply unit 41 includes: a combustor basket 42; an ignition burner 43 disposed on a central axis line of the combustor basket 42; a plurality of main burners 53 disposed in a circumferential direction around the ignition burner 43 at equal intervals; and a hat nozzle 51 disposed on the inner circumferential side of the outer cylinder 32 and an outer circumferential side of the combustor basket 42. Note that hereinafter, with respect to a direction in which the central axis line of the combustor basket 42 extends, a side in which a combustion gas G flows in the combustion liner 33 is referred to as a "downstream side", and the opposite side thereof is referred to as an "upstream side".The pilot burner 43 has a pilot nozzle 44 disposed on the central axis line of the combustion basket 42 and a tubular pilot air pipe 45 surrounding the outer periphery of the pilot nozzle 44. A downstream side of the ignition air pipe 45 forms an ignition cone 46 whose diameter gradually increases toward the downstream side. The inner peripheral side of the ignition air pipe 45 forms an ignition air passage 48 through which compressed air Ac from the compressor 11 flows as ignition air Ap. A pilot fuel Fp injected from the pilot nozzle 44 is burned (by diffusion combustion) in the pilot air Ap discharged from the pilot air passage 48 to form a diffusion flame 49.Each main burner 53 includes: a main air inner tubular cylinder 55 surrounding the outer periphery of the ignition air pipe 45; a main air outer tubular cylinder 56 surrounding the outer periphery of the main air inner cylinder 55; partition plates 57 dividing an annular space between the outer peripheral side of the main air inner cylinder 55 and the inner peripheral side of the main air outer cylinder 56 into a plurality of parts in the circumferential direction; and a main nozzle 54 provided between the plurality of partition plates 57. The plurality of spaces defined by the main air inside cylinder 55, the main air outside cylinder 56, and the plurality of partition plates 57 form a main air passage 58 in which the compressed air Ac from the compressor 11 flows as main air Am. A main fuel Fm is injected from the main nozzle 54 disposed in the main air passage 58 into the main air Am flowing in the main air passage 58. Therefore, a gas premixed which is a mixture of the main air Am and the main fuel Fm flows in the main air passage 58 further on the downstream side than a tip end portion (downstream end) of the main nozzle 54. After flowing out from the main air passage 58, this gas premixed is burned (by premixed combustion) and forms a premixed flame 59. the diffusion flame 49 described above satisfies a role of stabilizing this premixed flame 59.A space between the inner peripheral side of the outer cylinder 32 and the outer peripheral side of the combustor basket 42 forms a compressed air passage 52 that guides the compressed air Ac from the compressor 11 to the combustor basket 42. The hat nozzle 51 sprays a hat fuel Ft into this compressed air passage 52, and therefore, when hat fuel Ft is sprayed into the compressed air passage 52, the hat fuel Ft is mixed into the main air Am and the ignition air Ap.As illustrated in FIGS. 1 and 2, the gas turbine plant according to the present embodiment further includes: an ignition fuel line 61 that supplies the ignition fuel Fp to the ignition nozzle 44; a main fuel line 62 that supplies the main fuel Fm to the main nozzle 54; a top hat fuel line 63 that supplies the top hat fuel Ft to the top hat fuel nozzle 51; an ignition fuel valve 65 that adjusts a flow volume of the ignition fuel Fp; a main fuel valve 66 that adjusts a flow volume of the main fuel Fm; a top hat fuel valve 67 that adjusts a flow volume of the top hat fuel Ft; and a control device 100 that controls operations of the fuel valves 65, 66, 67, and the like.The pilot fuel line 61, the main fuel line 62, and the top hat fuel line 63 are all lines branched from a fuel line 60. The pilot fuel valve 65 is provided in the pilot fuel line 61, the main fuel valve 66 is provided in the main fuel line 62, and the hat valve 67 is provided in the hat fuel line 63.As illustrated in FIG. 1, the gas turbine plant according to the present embodiment further includes: a tachometer 71 that detects a rotational speed N of the gas turbine rotor 28; an output meter 72 that detects an output PW of the generator 29; an input temperature meter 73 that detects an input temperature Ti that is a temperature of air A introduced into the compressor 11; an input pressure meter 74 that detects an input pressure (atmospheric pressure) Pi that is a pressure of the air introduced into the compressor 11; a blade path temperature meter 75 that detects a blade path temperature Tb that is a temperature of the combustion gas immediately after the last stage of the turbine 21; and an exhaust temperature meter 76 that detects a temperature Te of exhaust gas in an exhaust stack downstream of the last stage of the turbine 21.As illustrated in FIG. 4, the control device 100 includes: an interface 180 that receives detection values from the detection measurement devices and the like; a combustion load command generator 110 that generates a combustion load command value CLCSO; a load percentage calculator 120 that detects a load percentage % load of the gas turbine at the present time; a fuel flow volume command generator 130 that generates a fuel flow volume command value CSO; an ignition ratio number calculator 140 pthat calculates an ignition ratio number (PL ratio number) that is the ratio of an ignition fuel flow volume Fpf to a total fuel flow volume; a hat ratio calculator 140 tthat calculates a hat ratio (TH ratio) that is the ratio of a hat flow volume Ftf to the total fuel flow volume; a system flow volume calculator 160 that determines flow volumes in the fuel lines 61, 62, and 63; and a valve controller 170 that outputs the control signals to the fuel valves 65, 66, and 67 in accordance with the flow volumes in the respective fuel lines 61, 62, and 63. Note that, in the present embodiment, the ignition ratio calculator 140 pand the hat ratio calculator 140 tform a flow ratio calculator 140.The combustion load command value CLCSO is a parameter made dimensionless which is an input temperature of the combustion gas in the turbine 21, and is a parameter having a positive correlation with the input temperature. The combustion load command value CLCSO is set to be 0% when the input temperature is at a lower limit value and 100% when the input temperature is at an upper limit value. For example, when the input temperature lower limit value is 700° C. and the input temperature upper limit value is 1,500° C., the combustion load command value CLCSO is expressed by the following formula.Note that 700° C.M.W. is the generator output when the input temperature is at its lower limit of 700° C., and 1,500° C.M.W. is the generator output when the input temperature is at its upper limit of 1,500° C.As illustrated in FIG. 5, the combustion load command generator 110 includes: a first output calculator 111 athat determines the generator output 700° C.M. occurring when the input temperature is the lower limit value of 700° C.; a second output calculator 111 bthat determines the generator output 1500° C.M. occurring when the input temperature is the upper limit value of 1,500° C.; a standard atmospheric pressure generator 112 that generates a predetermined standard atmospheric pressure Ps; a first divider 113 that determines an input pressure ratio Pr that is a ratio of the input pressure Pi determined by the input pressure meter 74 to the standard atmospheric pressure (standard atmospheric pressure) Ps; a first multiplier 114 athat multiplies the generator output 700° CMW obtained by the first output calculator 111 aby the input pressure ratio Pr; a second multiplier 114 bthat multiplies the generator output 1,500° CMW obtained by the second output calculator 111 bwith the input pressure ratio Pr; a first subtractor 115 athat subtracts the multiplication result obtained by the first multiplier 114 afrom the measured output PW of the generator 29 obtained by the output meter 72; a second subtractor 115 bthat subtracts the multiplication result obtained by the first multiplier 114 afrom the multiplication result obtained by the second multiplier 114 b; a second divider 116 that divides the subtraction result obtained from the first subtractor 115a by the subtraction result obtained from the second subtractor 115b; and a limiter 117 that reduces an increase / decrease ratio of the output from the second divider 116.The first output computing device 111 adetermines the generator output 700° C.MW When the input temperature is 700° C., using a function H 1 x, and using the input temperature Tiand an IGV opening command value as variable parameters. Meanwhile, the second output computing device 111 bdetermines the generator output 1500° C.MW occurring when the input temperature is 1,500° C., using a function H 2 x, and using the input temperature Ti and the IGV opening command value as variable parameters. Here, the IGV opening command value is a command value transmitted to the driver 16 of the IGV 14 by the control device 100. This IGV opening command value is obtained from the atmospheric pressure Pi, which is, for example, the pressure at the inlet of the compressor 11, a pressure at the outlet of the compressor 11, and the like. The output computing devices 111 aand 111 bchange the known values of 700° C.M.W. and 1,500° C.M.W., respectively, in the case where the input temperature and the IGV opening command value, reference values for values corresponding to the actual input temperature Ti and the IGV opening command value, and output the post-change values as 700° C.M.W. and 1,500° C.M.W., respectively.Further, the 700° CMW and the 1,500° CMW are corrected in accordance further based on a measured value Pi of the input pressure (atmospheric pressure). Specifically, the first divider 113 acquires the input pressure ratio Pr, which is the ratio of the input pressure (atmospheric pressure) Pi acquired by the input pressure gauge 74 to the standard input pressure (standard atmospheric pressure) Ps from the standard atmospheric pressure generator 112. The first multiplier 114 amultiplies the 700° CMW from the first output computing device 111 awith the input pressure ratio Pr and corrects the 700° CMW to a value corresponding to the input pressure ratio Pr. The second multiplier 114 bmultiplies the 1,500° CMW from the second output computing device 111 bwith the input pressure ratio Pr and corrects the 1,500° CMW to a value corresponding to the input pressure ratio Pr. In other words, by the above, the known values of 700° CMW and 1,500° CMW in the case where the input temperature and the IGV opening command value are reference values are corrected to values corresponding to the measured input temperature Ti, the IGV opening command value, and the measured input pressure ratio Pr.The first subtractor 115 a subtracts the 700° CMW corrected with the input pressure ratio Pr from the measured output PW of the generator 29 received from the output meter 72. In other words, the first subtractor 115 aobtains the value of the counter in the above formula. The second subtractor 115 b subtracts the 700° CMW corrected with the input pressure ratio Pr from the 1,500° CMW corrected with the input pressure ratio Pr. In other words, the second subtractor 115 bdetermines the value of the denominator in the above formula.The second divider 116 divides the value of the numerator in the above formula obtained by the first subtractor 115 awith the value of the denominator in the above formula obtained by the second subtractor 115 b, and outputs the resultant value as the combustion load command value. The limiter 117 limits the increase / decrease ratio number of the combustion load command value, which is a change value of the combustion load command value from the second divider 116 per unit time, such that the increase / decrease ratio number is less than or equal to a predetermined value.Although the above describes the lower limit value of the input temperature of the combustion gas in the turbine 21 as 700° C. and the upper limit value thereof as 1,500° C., the lower limit value and the upper limit value of the input temperature of the combustion gas in the turbine 21 may be set to different values from those in the above example depending on the model type of the combustor 31 and the like.The combustion load command value CLCSO with the increase / decrease ratio thereof limited by the limiter 117 is output from the combustion load command generator 110.The load percentage %Load of the gas turbine 10 is a percentage of a current load PW relative to a maximum load PWmax permitted in the state of the gas turbine 10 at the current time. As illustrated in FIG. 6, the load percentage calculation device 120 includes a maximum load calculation device 121 that determines the maximum load PWmax permitted in the state of the gas turbine 10 at the present time, and a divider 127 that divides the measured load PW, which is the output of the generator 29 and obtained by the output meter 72, by the maximum load PWmax.The maximum load calculator 121 includes: a first load coefficient calculator 122 that calculates a maximum load coefficient Ip based on the input pressure Pi; a second load coefficient calculator 123 that calculates a maximum load coefficient It based on the input temperature Ti; a first multiplier 124 that multiplies the maximum load coefficient Ip by the maximum load coefficient It; a mitigation coefficient generator 125 that generates a mitigation coefficient K based on an operation time of the gas turbine 10; and a second multiplier 126 that multiplies the multiplication result from the first multiplier 124 by the mitigation coefficient K. In other words, the maximum load calculator 121 acquires the maximum load PWmax based on the measured input pressure Pi acquired by the input pressure gauge 74, the measured input temperature Ti acquired by the input temperature gauge 73, and the mitigation coefficient K of the gas turbine 10.The fuel flow volume command value CSO is a value that specifies a total flow volume of the fuels supplied to the combustor 31 (hereinafter referred to as "total fuel flow volume"). As such, the fuel flow volume command generator 130 serves as a total flow volume computing device. Therefore, the fuel flow volume command generator 130 executes a total fuel flow volume calculation method for obtaining the total fuel flow volume.As illustrated in FIG. 7, the fuel flow volume command generator 130 includes: a rotation speed controller 131 that outputs a command value for controlling the total fuel flow volume such that the rotation speed N of the gas turbine rotor 28 becomes a target rotation speed; a load controller 132 that outputs a command value for controlling the total fuel flow volume such that the generator output PW corresponds to a generator output command value; a first temperature controller 133 that outputs a command value for controlling the total fuel flow volume such that the blade path temperature Tb of the gas turbine does not exceed an upper limit value; a second temperature controller 134 that outputs a command value for controlling the total fuel flow volume such that the exhaust temperature Te does not exceed an upper limit value; a low value selector 135 that outputs the smallest command value among the command values from the control devices 131 to 134; and a limiter 136 that limits an increase / decrease ratio number of the command from the low value selector 135.The rotation speed controller 131 receives the rotation speed N from the gas turbine rotor 28 from the rotation speed meter 71 and outputs a command value GVCSO for controlling the total fuel flow volume such that the rotation speed N of the gas turbine rotor 28 corresponds to the target rotation speed.Specifically, the rotation speed controller 131 compares the measured rotation speed N of the gas turbine rotor 28 with a predetermined GV setting value, and outputs a proportional control signal as the command value GVCSO.The load controller 132 receives the measured output PW of the generator 29 from the output meter 72 and the generator output command value from a host controller 90 (see FIG. 1 ). The load controller 132 outputs a command value for controlling the total fuel flow volume LDCSO such that the measured output PW corresponds to the generator output command value. Specifically, the load controller 132 compares the measured output PW with the generator output command value, calculates a proportional integral, and outputs the result thereof as the command value LDCSO.The first temperature controller 133 receives the blade path temperature Tb from the blade path temperature meter 75 and outputs a command value BPCSO for controlling the total fuel flow volume such that the blade path temperature Tb does not exceed the upper limit value. Specifically, the first temperature controller 133 compares the measured blade path temperature Tb with the upper limit value thereof, calculates a proportional integral, and outputs the result thereof as the command value BPCSO.The second temperature controller 134 receives the exhaust temperature Te from the exhaust temperature meter 76, and outputs a command value EXCSO for controlling the total fuel flow volume such that the exhaust temperature Te does not exceed the upper limit value. Specifically, the second temperature controller 134 compares the measured exhaust temperature Te with the upper limit value thereof, calculates a proportional integral, and outputs the result thereof as the command value EXCSO.The low value selector 135 selects the lowest command value among the command values from the control devices 131 to 134, and outputs the selected command value. The limiter 136 limits the increase / decrease ratio number of the command from the low value selector 135 and outputs the result as the fuel flow volume command value (total fuel flow volume command value) CSO.The ignition ratio (PL ratio) is a ratio of the ignition fuel flow volume Fpf to the total fuel flow volume. As illustrated in FIG. 9, the ignition ratio calculator 140 pincludes: a PL 0- ratio calculator (flow volume ratio calculator) 141 pthat acquires the PL 0- ratio that is the ignition ratio based on the combustion load command value CLCSO; a correction value calculator 142 pthat calculates a correction value based on the load percentage % load; a variation sensor 144 that detects a variation of the fuel flow volume command value CSO; and a corrector 151 that corrects the PL 0- ratio with the correction value.The PL 0- ratio calculation device 141 phas a function F 1 x defining the relationship between the combustion load command value CLCSO having a positive correlation with the input temperature of the combustion gas in the turbine 21 and the PL 0- ratio. As shown in FIG. 11, the function F 1 x is a function in which the PL 0- ratio gradually decreases as the combustion load command value CLCSO increases, or in other words, as the input temperature of the combustion gas increases. The PL 0- ratio calculation device 141 p receives the combustion load command value CLCSO from the combustion load command generator 110, and obtains the PL 0- ratio corresponding to this combustion load command value CLCSO using the function F 1 x. Although the relationship between the combustion load command value CLCSO and the PL 0- ratio is defined here by the function F 1 x, on the other hand, the relationship may be defined by a map.The correction value calculator 142 pincludes a rise time correction value calculator 143 pathat acquires a rise time correction value Ciwhen the fuel flow volume command value CSO increases, and a fall time correction value calculator 143 pbthat acquires a fall time correction value Cdwhen the fuel flow volume command value CSO decreases. As illustrated in FIG. 12, the rise time correction value calculator 143 pahas a function G 1 x defining a relationship between a load percentage %Load and the rise time correction value Ci based on the current load percentage %Load, and determines the rise time correction value Ci based on the current load percentage %Load. Meanwhile, the falling time correction value calculator 143 pbhas a function G 2 x defining a relationship between a load percentage %Load and the falling time correction value Cd based on the current load percentage %Load, and determines the falling time correction value Cd based on the current load percentage %Load.As illustrated in FIG. 12, the PL 0- ratio decreases as the load percentage %Load increases. Particularly, in cases where the load percentage %Load is a high load percentage such as 60% or more, there is a tendency toward further reduction in the PL 0- ratio to achieve reduction of NOx. As such, the conditions for burning the fuel in the combustion chamber 31 are more stringent in a stable manner in cases of high load percentage. The rise time correction value Ci and the fall time correction value Cd are correction values for correcting the PL 0- ratio and increasing the PL ratio in such cases of a high load percentage. Here, the falling time correction value Cd is set larger than the rising time correction value Ci at the same load percentage %Load.As described above, the combustion load command value CLCSO is a parameter having a positive correlation with the input temperature of the combustion gas in the turbine 21. As such, the combustion load command value CLCSO is a higher value when the input temperature is high and a smaller value when the input temperature is low. Incidentally, even if the inlet temperature of the combustion gas in the turbine 21 increases in response to the flow volume of fuel to the combustor 31 being increased, the generator output does not immediately increase. Likewise, even if the inlet temperature of the combustion gas in the turbine 21 decreases in response to the flow volume of fuel to the combustor 31 being reduced, the generator output does not decrease immediately. In other words, even if the inlet temperature of the combustion gas in the turbine 21 changes in response to the flow volume of fuel to the combustor 31 having been changed, the generator output does not change immediately. Accordingly, in the case where the flow volume of fuel to the combustor 31 has been increased or reduced, the combustion load command value CLCSO obtained using the measured generator output PW does not immediately become a value corresponding to the input temperature of the combustion gas in the turbine 21.Accordingly, in the case where the flow volume of fuel to the combustor 31 has been increased or reduced at a high load percentage representing conditions not conducive to the stable combustion of fuel, there is a risk that the combustion in the combustor 31 becomes unstable with a PL 0- ratio determined based on the combustion load command value CLCSO. Accordingly, in the present embodiment, the PL 0- ratio is corrected using the rise time correction value Ci and the fall time correction value Cd in the case where the flow volume of the fuel to the combustor 31 is increased or reduced at a high load percentage. There is a particularly strong tendency that the combustion in the combustion chamber 31 becomes unstable in the case where the flow volume of the fuel to the combustion chamber 31 is reduced, and thus, in the present embodiment, the PL 0- ratio is corrected using the falling time correction value Cd that is a value higher than the rising time correction value Ci. Thus, as described above, a post-correction PLd ratio for times with fuel reduction is a higher value than a post-correction PLi ratio for times with fuel increases.The rise time correction value calculator 143 paand the fall time correction value calculator 143 pbbeach receive the load percentage %Load from the load percentage calculator 120. The rise time correction value calculator 143 padetermines the rise time correction value Cibased on this load percentage %Load using the function G 1 x. Meanwhile, the falling time correction value calculator 143 pbb acquires the falling time correction value Cd based on this load percentage %Load using the function G 2 x.The variation sensor 144 includes: a delay unit 145 that outputs the fuel flow volume command value CSO from the fuel flow volume command generator 130 after a predetermined period of time; a subtractor 146 that detects a difference between the fuel flow volume command value CSO from the fuel flow volume command generator 130 and the fuel flow volume command value CSO from the delay unit 145; and a rise / fall determiner 147 that determines whether the fuel flow volume command value CSO rises by not less than a predetermined value or falls by not less than a predetermined value based on the subtraction result. In the case where the subtraction result from the subtractor 146 is a positive value and the value is not less than the predetermined value, the rise / fall determiner 147 outputs "+1", which means a rise. In the case where the subtraction result from the subtractor is a negative value and the value is not larger than the predetermined value, the rise / fall determining means 147 outputs "-1" which means a fall. In other cases, the rise / fall determiner 147 outputs "0", indicating that there is neither a rise nor a fall.The correction device 151 includes: a rise time coefficient generator 152 athat outputs a limiting coefficient that limits the rise / fall ratio number of the rise time correction value Ci; a fall time coefficient generator 152 bthat outputs a limiting coefficient that limits the rise / fall ratio number of the fall time correction value Cd; a first multiplier 153 athat multiplies the rise time correction value Ci by the limiting coefficient; a second multiplier 153 bthat multiplies the fall time correction value Cd by the limiting coefficient; and a summer (flow volume ratio correction device) 154 that adds the rise time correction value Ci or fall time correction value Cd whose rise / fall ratio number has been limited to the PL 0- ratio number. In the present embodiment, a PL 0- ratio in the case where the flow volume of fuel to the combustor 31 is increased or reduced during a high load percentage is corrected by adding the rise time correction value Ci or fall time correction value Cd whose rise / fall ratio has been limited to the PL 0- ratio determined based on the combustion load command value CLCSO in this manner. The addition result from the summer 154 is output from the ignition ratio calculator 140 pas a corrected PL ratio.Note that, in the present embodiment, the rise time coefficient generator 152 aand the first multiplier 153 aform a correction value setter that changes the correction value to be output so as to approach the rise time correction value Ci obtained by the rise time correction value calculator 143 pawith the temporal change. Further, in the present embodiment, the falling time coefficient generator 152 band the second multiplier 153 bform a correction value setter that changes the correction value to be output so as to approach the falling time correction value Cd obtained by the falling time correction value calculator 143 pbwith the time change.Operations of the ignition ratio calculator 140 pdescribed so far will be described in accordance with the flowchart illustrated in FIG. 15.The PL 0- ratio calculation device (flow volume ratio calculation device) 141 pof the ignition ratio calculation device 140 pdetermines the PL 0- ratio corresponding to the combustion load command CLCSO using the function F 1 x (S 1: a flow volume ratio calculation method).The correction value calculator 142 pof the ignition ratio calculator 140 pdetermines the correction values Ci and Cd based on the load percentage %Load (S 2: a correction value calculation method). Specifically, as described above, the rise time correction value calculator 143 paof the correction value calculator 142 pdetermines the rise time correction value Cibased on the current load percentage %Load using the function G 1 x (S 2 a:rise time correction value calculation method). Meanwhile, the falling time correction value calculator 143 pbb acquires the falling time correction value Cd based on the current load percentage % load using the function G 2 x (S 2 b: falling time correction value calculation method).The fluctuation sensor 144 of the ignition ratio number calculator 140 poutputs "+1" in the case where an amount by which the fuel flow volume command value CSO per unit time increases is not less than the predetermined value, and outputs "-1" in the case where an amount by which the fuel flow volume command value CSO per unit time decreases is not less than the predetermined value. In other cases, the fluctuation sensor 144 outputs "0", indicating that the fuel flow volume command value CSO per unit time does not increase or decrease (S 3 a fluctuation detection method).After the fluctuation sensor 144 outputs "+1" indicating that the fuel flow volume command value CSO increases or outputs "-1" indicating that the fuel flow volume command value CSO decreases, the correction device 151 corrects the PL 0- ratio that is calculated by the PL 0- ratio calculation device 141 pusing the correction value Ci or the correction value Cd that is received by the correction value calculation device 142 p(S 4: a correction method). Specifically, after the fluctuation sensor 144 outputs "+1", which means that the fuel flow volume command value CSO increases, the rising time coefficient generator 152 aof the correction device 151 outputs the limiting coefficient that limits the rising / falling ratio number of the rising time correction value Ci. Upon receipt of this limiting coefficient, the first multiplier 153 aof the corrector 151 multiplies the rise time correction value Ci from the rise time coefficient generator 152 awith this limiting coefficient, and outputs the rise time correction value Ci whose rise / fall ratio number has been limited. The summer 154 adds the rise time correction value Ci whose rise / fall ratio has been limited to the PL 0- ratio from the PL 0- ratio calculator 141 p, and outputs the result as the corrected PLi ratio (see FIG. 12 ) (S 4 a: a rise time correction method). Meanwhile, after the fluctuation sensor 144 outputs "-1", which means that the fuel flow volume command value CSO decreases, the falling time coefficient generator 152 boutputs the limiting coefficient that limits the increase / decrease ratio number of the falling time correction value Cd. Upon receipt of this limiting coefficient, the second multiplier 153b multiplies the falling time correction value Cd from the falling time coefficient generator 152b by its limiting coefficient, and outputs the falling time correction value Cd whose increase / decrease ratio number has been limited. The summer 154 adds the falling time correction value Cd whose increase / decrease ratio has been limited to the PL 0- ratio from the PL 0- ratio calculator 141 p, and outputs the result as the corrected PLd ratio (see FIG. 12 ) (S 4 b: a falling time correction method).Note that when the fluctuation sensor 144 outputs "0", the outputs from the first multiplier 153 aand the second multiplier 153 bbecomes "0", and thus the corrector 151 does not correct the PL 0- ratio from the PL 0- ratio calculator 141 p, and outputs the PL 0- ratio as the PL ratio. Further, in the case where the load percentage %Load is not a high load percentage, "0" is output from the correction value calculator 142 pas the correction value, and thus the outputs from the first multiplier 153 aand the second multiplier 153 balso become "0". Accordingly, even in the case where the load percentage %Load is not a high load percentage, the PL 0- ratio is not corrected by the PL 0- ratio calculation device 141 p, and the PL 0- ratio is output as the PL ratio. In other words, the correction device 151 corrects the PL 0- ratio from the PL 0- ratio calculation device 141 pin only the case where the load percentage % load is a high load percentage and the fuel flow volume command value CSO has increased or decreased by not less than a predetermined amount.Although the flowchart illustrated in FIG. 15 illustrates the correction value calculation process (S 2) as being performed after the execution of the flow volume ratio calculation process (S 1) and the variation detection process (S 3) is performed thereafter, the flow volume ratio calculation process (S 1), the correction value calculation process (S 2) and the variation detection process (S 3) are performed simultaneously.The hat ratio (TH ratio) is a ratio of the hat fuel flow volume Ftf to the total fuel flow volume. As illustrated in FIG. 10, the hat ratio calculator 140 tincludes: a TH 0- ratio calculator (flow volume ratio calculator) 141 tthat acquires the TH 0- ratio that is the hat ratio based on the combustion load command value CLCSO; a correction value calculator 142 tthat calculates a correction value based on the load percentage % load; a variation sensor 144 that detects the variation of the fuel flow volume command value CSO; and a corrector 151 that corrects the TH 0- ratio with a correction value.The TH 0- ratio calculation device 141 thas a function F 2 x defining a relationship between the combustion load command value CLCSO and the TH 0- ratio. As shown in FIG. 13, the function F 2 x is a function in which the TH 0- ratio gradually increases as the combustion load command value CLCSO increases, or in other words, as the input temperature of the combustion gas increases. The TH 0- ratio calculation device 141 t receives the combustion load command value CLCSO from the combustion load command generator 110, and obtains the TH 0- ratio corresponding to this combustion load command value CLCSO using the function F 2 x. Although the relationship between the combustion load command value CLCSO and the TH 0- ratio is defined here by the function F 2 x, on the other hand, the relationship may be defined by a map.The correction value calculator 142 tincludes a rise time correction value calculator 143 tathat acquires a rise time correction value Ci when the fuel flow volume command value CSO increases, and a fall time correction value calculator 143 tbthat acquires a fall time correction value Cd when the fuel flow volume command value CSO decreases. As illustrated in FIG. 14, the rise time correction value calculator 143 tahas a function G 3 x defining a relationship between a load percentage %Load and the rise time correction value Ci based on the current load percentage %Load, and determines the rise time correction value Ci based on the current load percentage %Load. Meanwhile, the falling time correction value calculator 143 tbhas a function G 4 x defining a relationship between a load percentage %Load and the falling time correction value Cd based on the current load percentage %Load. The rise time correction value Ci and the fall time correction value Cd are both negative values. Here, the falling time correction value Cd is set larger than the rising time correction value Ci at the same load percentage %Load. In other words, an absolute value of the falling time correction value Cd is set to be smaller than an absolute value of the rising time correction value Ci at the same load percentage %Load.As illustrated in FIG. 14, the TH 0- ratio substantially decreases as the load percentage %Load increases. However, here, in the case where the load percentage %Load is a high load percentage such as 60% or higher, the TH 0- ratio is substantially constant even when the load percentage %Load increases.In combustion chambers, depending on the structure of the combustion chamber, the characteristics of the fuel supplied to the combustion chamber, and the like, combustion fluctuation is strongly liable to occur at load percentages arising with such structures and the like. With the combustor 31 according to the present embodiment, the tendency for combustion fluctuation to occur at high load percentages becomes more severe. With the combustor 31 according to the present embodiment, combustion variation can be prevented by reducing the TH ratio at such high load percentages and as the fuel flow volume command value CSO increases or decreases. Accordingly, the rise time correction value Ci and the fall time correction value Cd for the TH 0- ratio of the present embodiment are both negative correction values that reduce the post-correction TH ratio in the case of a high load percentage.The fluctuation sensor 144 has the same configuration as the fluctuation sensor 144 of the ignition ratio number calculator 140 p. Accordingly, the fluctuation sensor 144 outputs "+1" in the case where an increase in which an amount by which the fuel flow volume command value CSO per unit time increases is not less than a predetermined value, and outputs "-1" in the case where an amount by which the fuel flow volume command value CSO per unit time decreases is not less than a predetermined value. In other cases, the fluctuation sensor 144 outputs "0", indicating that the fuel flow volume command value CSO per unit time does not increase or decrease.The correction device 151 has the same configuration as the correction device 151 of the ignition ratio number calculator 140 p. Accordingly, after the fluctuation sensor 144 outputs "+1" indicating that the fuel flow volume command value CSO increases or outputs "-1" indicating that the fuel flow volume command value CSO decreases, the correction device 151 corrects the TH 0- ratio that is received from the TH 0- ratio calculation device 141 tusing the correction value Ci or the correction value Cd that is received from the correction value calculation device 142 t.Operations of the hat ratio calculator 140 tdescribed above are the same as the operations of the ignition ratio number calculator 140 pdescribed above using FIG. 15. However, the rise time correction value Ci and the fall time correction value Cd obtained by the correction value calculation device 142 tof the hat ratio calculator 140 tare both negative values, and thus a THi ratio and a THd ratio corrected by the correction device 151 (see FIG. 14 ) are both smaller than the pre-correction TH 0- ratio.The above describes an example of correcting the TH 0- ratio for a combustion chamber 31 in which there is a strong tendency for combustion fluctuation to occur at high load percentages. However, there are also combustion chambers in which combustion fluctuation is highly liable to occur at medium load percentages such as about 50% to 60%. In this case, the correction value calculator 142 tdetermines a correction value for an average load percentage as the correction value of the TH 0- ratio. Further, the above describes an example of correcting the TH 0- ratio for a combustion chamber 31 that can suppress combustion fluctuation by reducing the TH ratio. However, there are also combustion chambers that can suppress combustion fluctuation by increasing the TH ratio. In this case, the correction device 151 determines a positive correction value for correcting the TH 0- ratio and adds this correction value to the TH 0- ratio. In addition, the falling time correction value Cd in the above is set larger than the rising time correction value Ci at the same load percentage %Load. However, depending on the combustor, there are also cases where the falling time correction value Cd is set to be smaller than the rising time correction value Ci at the same load percentage %Load.As illustrated in FIG. 8, the system flow volume calculation device 160 includes: a first multiplier 161 that determines the ignition fuel flow volume Fpf using the PL ratio obtained by the ignition ratio number calculator 140 p; a second multiplier 162 that determines the shuttle fuel flow volume Ftf using the TH ratio calculated by the shuttle ratio number calculator 140 t; a first subtracter 163 that subtracts the shuttle fuel flow volume Ftf from the flow volume command value CSO specifying the total fuel flow volume; and a second subtracter 164 that further subtracts the ignition fuel flow volume Fpf from the subtraction result received by the first subtracter 163.The first multiplier 161 obtains the pilot fuel flow volume Fpf by multiplying the fuel flow volume command value CSO specifying the total fuel flow volume by the PL ratio obtained by the pilot ratio calculator 140 p, and outputs the pilot fuel flow volume Fpf to the valve controller 170. The second multiplier 162 obtains the hat fuel flow volume Ftf by multiplying the fuel flow volume command value CSO specifying the total fuel flow volume by the TH ratio obtained by the hat ratio calculator 140 t, and outputs the hat fuel flow volume Ftf to the valve controller 170. The first subtracter 163 subtracts the top hat fuel flow volume Ftf from the fuel flow volume command value CSO specifying the total fuel flow volume as described above. The second subtractor 164 further subtracts the pilot fuel flow volume Fpf from the subtraction result obtained from the first subtractor 163, and outputs the subtraction result to the valve control device 170 as a main fuel flow volume Fmf. In other words, the system flow volume computing device 160 executes a system flow volume computing method for obtaining each of the fuel flow volumes.As illustrated in FIG. 8, the valve control device 170 includes: a valve driving amount calculator 171 that detects a driving amount of the ignition fuel valve 65; a valve control signal generator 175 that outputs a control signal to the ignition fuel valve 65; a valve driving amount calculator 172 that detects a driving amount of the top hat fuel valve 67; a valve control signal generator 176 that outputs a control signal to the top hat signal valve 67; a valve driving amount calculator 173 that detects a driving amount of the main fuel valve 66; and a valve control signal generator 177 that outputs a control signal to the main fuel valve 66.The valve driving amount calculator 171 that acquires the driving amount of the pilot fuel valve 65 acquires the driving amount of the pilot fuel valve 65 in accordance with the pilot fuel flow volume Fpf acquired by the system flow volume calculator 160. The valve control signal generator 175 generates a control signal based on the driving amount of the pilot fuel valve 65, and outputs the control signal to the pilot fuel valve 65. The valve driving amount calculator 172, which acquires the driving amount of the hat fuel valve 67, acquires the driving amount of the hat fuel valve 67 in accordance with the hat fuel flow volume Ftf acquired by the system flow volume calculator 160. The valve control signal generator 176 generates a control signal based on the amount of drive of the hat fuel valve 67 and outputs the control signal to the hat fuel valve 67. The valve driving amount calculator 173 that acquires the driving amount of the main fuel valve 66 acquires the driving amount of the main fuel valve 66 in accordance with the main fuel flow volume Fmf acquired by the system flow volume calculator 160. The valve control signal generator 177 generates a control signal based on the drive amount of the main fuel valve 66, and outputs the control signal to the main fuel valve 66. In other words, the valve control device 170 performs a valve control method for outputting a control signal to each fuel valve.After outputting the control signals to the fuel valves 65, 66, and 67 from the valve control signal generators 175, 176, and 177, respectively, the fuel valves 65, 66, and 67 operate in accordance with the driving amounts specified by the respective control signals. Therefore, the ignition fuel Fp flows into the ignition fuel pipe 61 with the flow volume Fpf based on the PL ratio obtained by the ignition ratio calculator 140 p. The hat fuel Ft flows into the hat fuel line 63 at the flow volume Ftf based on the TH ratio obtained by the hat ratio calculator 140 t. In addition, the main fuel Fm flows into the main fuel pipe 62 with the flow volume Fmf received by subtracting the pilot fuel flow volume Fpf and the top hat fuel flow volume Ftf from the total fuel flow volume.As described above, according to the present embodiment, the flow volume ratio of each fuel determined based on the combustion load command value CLCSO is corrected in accordance with the load percentage of the gas turbine when the fuel flow volume command value CSO has changed. Accordingly, transient combustion fluctuation occurring when the load changes can be suppressed, and the combustion stability in the combustion chamber 31 can be improved. According to the present embodiment, combustion stability in combustion chambers can be further improved at times of load drops and at times of load increases, and at times of return operations.The flow volume ratio calculators 140 pand 140 tof the present embodiment determine the pre-correction flow volume ratio of each fuel based on the combustion load command value CLCSO. However, the flow volume ratio calculators 140 pand 140 tmay determine the pre-correction flow volume ratio of each fuel based on a value correlated with the input temperature, which is a value that changes in correlation with changes in the input temperature of the combustion gas in the turbine 21, or that is this input temperature.The combustion state of the combustion chamber 31 can be specified by the value correlated with the above-described input temperature and a value correlated with the flow velocity that changes in correlation with changes in the flow velocity of the combustion gas in the combustion chamber 31. This flow velocity correlated value includes, besides the load percentage used when the correction value is obtained, the output of the gas turbine 10 (the generator output), the total flow volume of the fuel supplied to the combustor 31, the flow volume of air introduced into the compressor 11, and the like. Accordingly, in the case where the above-described value correlated with the input temperature is taken as a first parameter and the pre-correction flow volume ratio of each fuel is determined using this first parameter, one of the output of the gas turbine 10, the flow volume of all fuels supplied to the combustor 31, the flow volume of air introduced into the compressor 11, and the like may be taken as a second parameter and the correction value determined using this second parameter.The variation sensor 144 of the present embodiment detects a variation of a load command by detecting a variation of the fuel flow volume command value CSO. However, unlike the fuel flow volume command value CSO, the variation sensor 144 may detect a variation of the load correlated value, which is a value that changes in correlation with the changes in the load of the gas turbine, or which is a load value (the generator output).According to the present invention, combustion stability in combustion chambers at times of load drops and at times of load rises and at times of return operations can be improved.10 Gas turbine 11 Compressor 14 IGV 21 Turbine 31 Combustor 33 Combustion liner (or transition piece) 43 Ignition burner 44 Ignition nozzle 51 Top hat nozzle 53 Main burner 54 Main nozzle 60 Fuel line 61 Ignition fuel line 62 Main fuel line 63 Top hat fuel line 65 Ignition fuel valve 66 Main fuel valve 67 Top hat fuel valve 71 Tachometer 72 Output gauge 73 Input temperature gauge 74 Input pressure gauge 75 Blade path temperature gauge 76 Exhaust temperature gauge 100 Controller 110 Combustion load command generator 120 Load percentage calculator 130 Fuel flow volume command generator (total flow volume calculator) 140 Flow ratio number calculator (flow volume ratio calculator) 140 p Ignition ratio number calculator 141 p PL 0- Ratio number calculator (Flow Volume Ratio Calculation Device) 142 pCorrect value Calculation Device 143 pa AnstiegszeitTime Correction Value Calculation Device 144 Fluctuation Sensor 151 Correction Device 154 Summer (Flow Volume Ratio Correction Device) 140 tHut Ratio Calculator 141 tTH 0- Ratio Calculation Device (Flow Volume Ratio Calculation Device) 142 tCorrect value Calculation Device 143 taTime Correction Value Calculation Device 160 System Flow Volume Calculation Device 170 Valve Control Device 180 Interface

Claims

A flow ratio calculation device for use in a gas turbine (10), the gas turbine (10) comprising a plurality of fuel systems, a compressor (11) configured to generate compressed air by compressing air, a combustor (31) configured to generate a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine (21) drivable by the combustion gas, wherein the flow ratio calculation device is configured to calculate a flow volume ratio of the fuels flowing in the plurality of fuel systems, and comprises: a flow volume ratio calculation device (140) configured to calculate a value of a first parameter among a plurality of parameters capable of expressing a combustion state in the combustor (31), receiving the flow volume ratio number based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio number; a correction value calculation device (142p) configured to acquire a correction value of the flow volume ratio number at a time when a load of the gas turbine (10) changes; a variation sensor (144) configured to acquire a variation of a value correlated with the load that is a value that changes in correlation with changes in the load of the gas turbine (10) or that is a value of the load; and a correction device (151) configured to, after acquiring a variation of the value correlated with the load from the variation sensor (144), acquire the flow volume ratio number, the correction value acquired by the flow volume ratio calculation device (140) to correct with the correction value acquired by the correction value calculation device (142p), wherein the correction value calculation device (142p) is configured to receive a value of a second parameter different from the first parameter among the plurality of parameters and acquire the correction value based on the received value of the second parameter using a predetermined relationship between the second parameter and the correction value, wherein the correction value calculation device (142p) includes a rise time correction value calculation device (143pa) configured to acquire a correction value based on the value of the second parameter when the value correlated with the load rises by calculating a predetermined rise time relationship between the second parameter and the correction value at a time point, using a falling time correction value calculating device (143pb) configured to determine a correction value based on the value of the second parameter when the value correlated with the load falls by using a predetermined falling time relationship between the second parameter and the correction value at a time when the value correlated with the load falls; Wherein the correction device (151) is configured to correct the flow volume ratio obtained by the flow volume ratio calculation device (140) with the correction value obtained by the rise time correction value calculation device (143pa) after the variation sensor (144) detects a rise in the value correlated with the load, and to correct the flow volume ratio obtained by the flow volume ratio calculation device (140) with the correction value obtained by the fall time correction value calculation device (143pb) after the variation sensor (144) detects a fall in the value correlated with the load.The flow ratio calculation device according to claim 1, wherein the correction device (151) includes a correction value setter configured to change the correction value to be output so as to approximate the correction value obtained by the correction value calculation device (142p) with the time change, and a flow volume ratio correction device configured to correct the flow volume ratio obtained by the flow volume ratio calculation device (140) with the correction value output by the correction value setter.A flow ratio calculation device for use in a gas turbine (10), the gas turbine (10) comprising a plurality of fuel systems, a compressor (11) configured to generate compressed air by compressing air, a combustor (31) configured to generate a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine (21) drivable by the combustion gas, wherein the flow ratio calculation device is configured to calculate a flow volume ratio of the fuels flowing in the plurality of fuel systems, and comprises: a flow volume ratio calculation device (140) configured to calculate a value of a first parameter among a plurality of parameters capable of expressing a combustion state in the combustor (31), receiving the flow volume ratio number based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio number; a correction value calculation device (142p) configured to acquire a correction value of the flow volume ratio number at a time when a load of the gas turbine (10) changes; a variation sensor (144) configured to acquire a variation of a value correlated with the load that is a value that changes in correlation with changes in the load of the gas turbine (10) or that is a value of the load; and a correction device (151) configured to, after acquiring a variation of the value correlated with the load from the variation sensor (144), acquire the flow volume ratio number, A flow volume ratio calculated by the flow volume ratio calculation device (140) to be corrected with the correction value calculated by the correction value calculation device (142p), wherein the correction device (151) comprises a correction value setter configured to change the correction value to be output so as to be approximated to the correction value calculated by the correction value calculation device (142p) with the time variation, and a flow volume ratio correction device configured to correct the flow volume ratio calculated by the flow volume ratio calculation device (140) with the correction value output by the correction value setter.The flow ratio calculation device according to claim 3, wherein the correction value calculation device (142p) is configured to receive a value of a second parameter different from the first parameter among the plurality of parameters, and determine the correction value based on the received value of the second parameter using a predetermined relationship between the second parameter and the correction value.The flow ratio calculation device according to any one of claims 1 to 4, wherein the combustion chamber (31) comprises an ignition burner (43) and a main burner (53) configured to inject fuels; wherein the gas turbine (10) comprises, as the plurality of fuel systems, an ignition fuel system configured to supply a fuel to the ignition burner (43) and a main fuel system configured to supply a fuel to the main burner (53); and wherein the flow volume ratio number comprises an ignition fuel ratio number that is a ratio of a flow volume of the fuel supplied to the combustion chamber (31) from the ignition fuel system relative to a total flow volume of the fuels supplied to the combustion chamber (31) from the plurality of fuel systems.A flow ratio calculation device for use in a gas turbine (10), the gas turbine (10) comprising a plurality of fuel systems, a compressor (11) configured to generate compressed air by compressing air, a combustor (31) configured to generate a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine (21) drivable by the combustion gas, wherein the flow ratio calculation device is configured to calculate a flow volume ratio of the fuels flowing in the plurality of fuel systems, and comprises: a flow volume ratio calculation device (140) configured to calculate a value of a first parameter among a plurality of parameters capable of expressing a combustion state in the combustor (31), receiving the flow volume ratio based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio; a correction value calculator (142p) configured to determine a correction value of the flow volume ratio at a time when a load of the gas turbine (10) changes; a variation sensor (144) configured to detect a variation of a value correlated with the load, which is a value that changes in correlation with changes in the load of the gas turbine (10), or which is a value of the load; and a correction device (151) configured to, after detecting a variation of the load correlated value from the variation sensor (144), correct the flow volume ratio obtained by the flow volume ratio calculation device (140) with the correction value obtained by the correction value calculation device (142p), wherein the correction value calculation device (142p) is configured to receive a value of a second parameter different from the first parameter among the plurality of parameters and determine the correction value based on the received value of the second parameter using a predetermined relationship between the second parameter and the correction value, wherein the combustor (31) includes an ignition burner (43) and a main burner (53) configured to inject fuels; wherein the gas turbine (10) includes, as the plurality of fuel systems, an ignition fuel system configured to supply a fuel to the ignition burner (43) and a main fuel system configured to supply a fuel to the main burner (53); wherein the flow volume ratio includes an ignition fuel ratio that is a ratio of a flow volume of the fuel supplied to the combustion chamber (31) from the ignition fuel system relative to a total flow volume of the fuels supplied to the combustion chamber (31) from the plurality of fuel systems; wherein the correction value calculation device (142p) includes a rise time correction value calculation device (143pa) configured to determine a correction value based on the value of the second parameter when the value correlated with the load increases by using a predetermined rise time relationship between the second parameter and the correction value at a time when the value correlated with the load increases, and a fall time correction value calculation device (143pb) configured to determine a correction value based on the value of the second parameter when the value correlated with the load decreases by using a predetermined fall time relationship between the second parameter and the correction value at a time when the value correlated with the load decreases; wherein the correction device (151) is configured to correct the flow volume ratio obtained by the flow volume ratio calculation device (140) with the correction value obtained by the rise time correction value calculation device (143pa) after the variation sensor (144) detects a rise in the value correlated with the load, and to correct the flow volume ratio obtained by the flow volume ratio calculation device (140) with the correction value obtained by the fall time correction value calculation device (143pb) after the variation sensor (144) detects a fall in the value correlated with the load; and wherein the falling time correction value calculation means (143pb) is configured to calculate a correction value having a value larger than the correction value obtained by the rising time correction value calculation means (143pa) when the value of the second parameter is the same value.The flow ratio calculation device according to claim 1, 2, 4, or 6, wherein the first parameter is a value correlated with the input temperature, which is a value that changes in correlation with changes in an input temperature of the combustion gas in the turbine, or which is the input temperature, and the second parameter is one of an output of the gas turbine (10), a load percentage that is a percentage of a current load relative to an allowed maximum load of the gas turbine (10), a flow volume of all fuels supplied to the combustor (31) from the plurality of fuel systems, and a flow volume of air sucked by the compressor (11).The flow ratio calculation device according to claim 1 or 3, wherein the combustor (31) comprises an ignition burner (43) and a main burner (53) configured to inject fuels; wherein the gas turbine (10) comprises, as the plurality of fuel systems, an ignition fuel system configured to supply a fuel to the ignition burner (43) and a main fuel system configured to supply a fuel to the main burner (53); wherein the flow volume ratio comprises an ignition fuel ratio that is a ratio of a flow volume of the fuel supplied to the combustor (31) from the ignition fuel system relative to a total flow volume of the fuels supplied to the combustor (31) from the plurality of fuel systems; and wherein the correction value computing device (142p) is configured to compute the correction value to increase the ignition fuel ratio computed by the flow volume ratio computing device (140).The flow ratio calculation device according to claim 8, wherein the correction device (151) is configured to, after the variation sensor (144) detects a drop in the value correlated with the load, correct the ignition fuel ratio using the correction value obtained by the correction value calculation device (142p), such that the ignition fuel ratio calculated by the flow volume ratio calculation device (140) increases.The flow ratio calculation device according to any one of claims 1 to 9, wherein the combustion chamber (31) comprises a burner configured to inject a fuel; wherein the gas turbine (10) comprises, as the plurality of fuel systems, a burner fuel system configured to supply a fuel to the burner and a cylinder head fuel system configured to supply a fuel to the air supplied to the burner; and the flow volume ratio comprises a top hat fuel ratio that is a ratio of a flow volume of the fuel supplied to the combustion chamber from the top hat fuel system relative to a total flow volume of the fuels supplied to the combustion chamber (31) from the plurality of fuel systems.A control device (100) comprising: the flow ratio calculation device (140) according to any one of claims 1 to 10; a total flow volume calculation device (130) configured to acquire the total flow volume of the fuels supplied to the combustor (31) from the plurality of fuel systems; a system flow volume calculation device (160) configured to acquire, using the total flow volume, a fuel flow volume for each of the plurality of fuel systems acquired by the total flow volume calculation device (130) and the flow volume ratio calculated by the flow ratio calculation device (140); and a valve control device (170) configured to output a control signal to a fuel flow volume control valve provided in each of the plurality of fuel systems such that the fuel flow volume in each of the plurality of fuel systems becomes the fuel flow volume determined by the system flow volume calculation device.The control device (100) according to claim 11, further comprising: a combustion load command generator (110) configured to generate a combustion load command value that changes in positive correlation with changes in the input temperature of the combustion gas in the turbine (10), wherein the flow volume ratio calculation device (140) of the flow ratio calculation device is configured to calculate a flow volume ratio based on the combustion load command value using the combustion load command value as a value of the first parameter.The control device (100) according to claim 11 or 12, wherein the variation sensor (144) is configured to detect a variation in the value correlated with the load, the total flow volume obtained by the total flow volume calculation device (130) serving as the value correlated with the load.A gas turbine plant comprising: the control device (100) according to any one of claims 11 to 13; and the gas turbine (10).A flow ratio calculation method used in a gas turbine (10), the gas turbine (10) comprising a plurality of fuel systems, a compressor (11) that generates compressed air by compressing air, a combustor (31) that generates a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine (21) driven by the combustion gas, wherein the flow volume ratio calculation method calculates a flow volume ratio of the fuels flowing in the plurality of fuel systems, and comprising: a flow volume ratio calculation method for receiving a value of a first parameter among a plurality of parameters that can express a combustion state in the combustor (31), and determining the flow volume ratio based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio; a correction value calculation method for determining a correction value of the flow volume ratio at a time when a load of the gas turbine (10) changes; a variation detection method for detecting a variation of a value correlated with the load, which is a value that changes in correlation with changes in the load of the gas turbine (10) or which is a value of the load; and after detecting a variation of the value correlated with the load in the variation detection method, a correction method for correcting the flow volume ratio determined in the flow volume ratio calculation method with the correction value, the correction value calculation method that is acquired by the correction value calculation method, wherein in the correction value calculation method, a value of a second parameter different from the first parameter among the plurality of parameters is received, and the correction value is acquired based on the received value of the second parameter using a predetermined relationship between the second parameter and the correction value, wherein the correction value calculation method includes a rise time correction value calculation method for acquiring a correction value based on the value of the second parameter when the value correlated with the load rises by using a predetermined rise time relationship between the second parameter and the correction value of the flow volume ratio number at a time when the value correlated with the load rises, and a fall time correction value calculation method for acquiring a correction value based on the value of the second parameter, when the load correlated value decreases by using a predetermined falling time relationship between the second parameter and the flow volume ratio correction value at a time when the load correlated value decreases; and in the correction method, after an increase in the load correlated value is detected in the variation detection method, the flow volume ratio obtained in the flow volume ratio calculation method is corrected with the correction value detected in the rising time correction value calculation method, and after a decrease in the load correlated value is detected in the variation detection method, the flow volume ratio obtained in the flow volume ratio calculation method is corrected with the correction value obtained in the falling time correction value calculation method.The flow ratio calculation method according to claim 15, wherein the correction method comprises a correction value setting method for changing the correction value to be output to be approximated to the correction value obtained in the correction value time-varying calculation method, and a flow volume ratio calculation method for correcting the flow volume ratio obtained in the flow volume ratio calculation method using the correction value changed in the correction value setting method.A flow ratio calculation method used in a gas turbine (10), the gas turbine (10) comprising a plurality of fuel systems, a compressor (11) that generates compressed air by compressing air, a combustor (31) that generates a combustion gas by burning fuels from the plurality of fuel systems in the compressed air, and a turbine (21) driven by the combustion gas, wherein the flow volume ratio calculation method calculates a flow volume ratio of the fuels flowing in the plurality of fuel systems, and comprising: a flow volume ratio calculation method for receiving a value of a first parameter among a plurality of parameters that can express a combustion state in the combustor (31), and determining the flow volume ratio based on the received value of the first parameter using a predetermined relationship between the first parameter and the flow volume ratio; a correction value calculation method for determining a correction value of the flow volume ratio at a time when a load of the gas turbine (10) changes; a variation detection method for detecting a variation of a value correlated with the load, which is a value that changes in correlation with changes in the load of the gas turbine (10), or which is a value of the load; After detecting a variation of the value correlated with the load in the variation detection method, a correction method for correcting the flow volume ratio obtained in the flow volume ratio calculation method with the correction value obtained in the correction value calculation method, the correction method comprising a correction value setting method for changing the correction value to be output to be approximated to the correction value obtained in the correction value time-varying calculation method, and a flow volume ratio calculation method for correcting the flow volume ratio obtained in the flow volume ratio calculation method using the correction value changed in the correction value setting method.A fuel system control method that executes the flow ratio calculation method according to any one of claims 15 to 17, and further executes: a total flow volume calculation method for obtaining a total flow volume of the fuels supplied to the combustor (31) from the plurality of fuel systems; a system flow volume calculation method for obtaining a fuel flow volume for each of the plurality of fuel systems using the total flow volume obtained in the total flow volume calculation method and the flow volume ratio calculated by the flow volume ratio calculation method; and a valve control method for outputting a control signal to a fuel flow volume control valve provided in each of the plurality of fuel systems such that the fuel flow volume in each of the plurality of fuel systems becomes the fuel flow volume obtained in the system flow volume calculation method.

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