Control device, gas turbine, control method and program

Abstract

To provide a technique for performing control so that a temperature of cooling air during switching of fuel becomes a target temperature.SOLUTION: A control device is for a fuel switching type gas turbine having a cooler that cools part of compressed air extracted from a compressor. The control device includes: means for acquiring a fuel switching signal; means for controlling an opening of an inlet guide vane; and means for controlling an outlet side temperature of the cooler, the means switching whether an outlet side temperature is controlled by using a control value corresponding to an output value of the gas turbine or the outlet side temperature is controlled by using a control value calculated through feedback control based on a deviation of a measurement value from a target value of the outlet side temperature in accordance with the output value of the gas turbine. When the fuel switching signal is acquired, the opening of the inlet guide vane is increased, and the outlet side temperature is controlled by using the control value calculated through the feedback control.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device, a gas turbine, a control method, and a program. [Background technology]

[0002] Coolers such as TCA (Turbine Cooling Air) coolers are available that exchange heat between the compressed air compressed by the gas turbine compressor and the fuel supplied to the combustor, cooling the compressed air and superheating the fuel, and then supplying the cooled compressed air to the turbine or combustor. The heat exchanger of the TCA cooler is equipped with a fan, and the temperature of the compressed air at the TCA cooler outlet is controlled by adjusting the fan's airflow. Conventionally, the rotation speed of this fan has been determined based on the load of the gas turbine.

[0003] Also, combustors known as dual-fired or dual-fuel combustors have been proposed, which are configured to switch between gas fuel and oil fuel and supply them to the combustor of a gas turbine. When switching the type of fuel supplied to a dual-fired combustor, the temperature controllability of the compressed air (referred to as cooling air) at the outlet of the TCA cooler may decrease, causing the temperature to deviate from a predetermined target temperature. If the temperature of the cooling air deviates from the target temperature, it will affect the operation of the gas turbine.

[0004] Patent Document 1 discloses a technology for controlling the temperature of cooling air for cooling the turbine by setting a target temperature of the cooling air according to the operating state of the gas turbine and performing feedback control for the target temperature. However, Patent Document 1 does not disclose how to control the temperature of the cooling air when the type of fuel is switched. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-115666 Summary of the Invention [Problem to be solved by the invention]

[0006] A technology is provided for controlling the temperature of cooling air at the time of fuel switching so that it reaches a target temperature.

[0007] The present disclosure provides a control device, a gas turbine, a control method, and a program that can solve the above-mentioned problems. [Means for solving the problem]

[0008] A control device according to the present disclosure is a control device for a gas turbine that includes a compressor, a combustor, a turbine section, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel to be supplied to the combustor, and that can switch the fuel to be supplied to the combustor to one of a plurality of types of fuel, and includes a signal acquisition means that acquires a fuel switching signal indicating that the fuel to be supplied to the combustor is being switched, an inlet guide vane control means that controls an opening degree of an inlet guide vane of the compressor, and a means for controlling a cooling temperature, which is the temperature of the compressed air at the outlet side of the cooler, and that controls the cooling temperature by a control value corresponding to an output value of the gas turbine. and a cooling control means that switches between controlling the cooling temperature by a value obtained by adding the correction amount to the control value, and controlling the cooling temperature by a value obtained by controlling the cooling temperature by a value obtained by adding the correction amount to the control value, in accordance with an output value of the gas turbine, when the signal acquisition means acquires the fuel switching signal, the inlet guide vane control means increases the opening of the inlet guide vane, and the cooling control means executes the feedback control to control the cooling temperature by a value obtained by adding the correction amount to the control value.

[0009] A gas turbine according to the present disclosure includes a compressor, a combustor capable of switching between and supplying one of a plurality of types of fuel, a turbine section, a cooler that performs heat exchange between a portion of the compressed air compressed by the compressor and the fuel supplied to the combustor, and the above-described control device.

[0010] A control method according to the present disclosure is a control method for a gas turbine including a compressor, a combustor, a turbine section, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel to be supplied to the combustor, and is capable of switching the fuel to be supplied to the combustor to one of a plurality of types of fuel, the control method comprising the steps of: acquiring a fuel switching signal indicating that the fuel to be supplied to the combustor is being switched; increasing an opening degree of an inlet guide vane of the compressor; performing feedback control based on a deviation between a target value of a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and a measured value of the cooling temperature; calculating a correction amount to achieve the target value of the cooling temperature; and controlling the cooling temperature with a value obtained by adding the correction amount to a control value corresponding to an output value of the gas turbine.

[0011] A program according to the present disclosure causes a computer to execute a process of controlling a gas turbine including a compressor, a combustor, a turbine unit, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel to be supplied to the combustor, and that is capable of switching the fuel to be supplied to the combustor to one of a plurality of types of fuel, the program acquiring a fuel switching signal indicating that the fuel to be supplied to the combustor is being switched, increasing an opening degree of an inlet guide vane of the compressor, performing feedback control based on a deviation between a target value of a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and a measured value of the cooling temperature, calculating a correction amount for achieving the target value of the cooling temperature, and controlling the cooling temperature with a value obtained by adding the correction amount to a control value corresponding to an output value of the gas turbine. [Effects of the Invention]

[0012] According to the control device, gas turbine, control method, and program of the present disclosure, the temperature of the cooling air at the time of fuel switching can be controlled to reach a target temperature. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a gas turbine facility according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram illustrating an example of a control device according to the embodiment. [Figure 3] FIG. 6 is a diagram illustrating an example of a setting logic for a fan rotation speed according to the embodiment. [Figure 4] 3A and 3B are diagrams illustrating load changes and control at the time of fuel switching in the gas turbine according to the embodiment. [Figure 5] 4 is a flowchart illustrating an example of control according to the embodiment. [Figure 6] FIG. 2 illustrates an example of a hardware configuration of a control device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Embodiment> Hereinafter, a gas turbine control method according to the present disclosure will be described with reference to the drawings. (composition) FIG. 1 is a diagram illustrating an example of a schematic configuration of a gas turbine facility according to an embodiment. 1, the gas turbine facility of this embodiment includes a gas turbine 1, a generator 20, and a control device 100 that controls the gas turbine 1. The gas turbine 1 includes an inlet guide vane (IGV) 10 that adjusts the amount of air flowing into a compressor 2, the compressor 2 that compresses the flowing air to generate compressed air, a combustor 3 that mixes the compressed air compressed by the compressor 2 with fuel and burns the fuel to generate high-temperature combustion gas, a turbine 4 that rotates a rotor 5 with the combustion gas to drive a generator 20, a casing 6 that is disposed between the compressor 2 and the turbine 4 and in which the combustor 3 is installed, a fuel system 7 that supplies fuel to the combustor 3, a TCA cooler 8, and a switching device 9 that switches the fuel supplied to the fuel system 7 between gas fuel and oil fuel. The combustor 3 is a dual-fired combustor that burns fuel by switching between gas firing and oil firing. A temperature sensor 11 that measures the temperature of the air taken in by the compressor is attached to the inlet side of the compressor 2, a temperature sensor 12 that measures the temperature of the cooling air is attached to the outlet side of the TCA cooler 8, and an output sensor 21 is attached to the generator 20. The measurement value of the output sensor 21 is used as the output value (load) of the gas turbine 1. The values ​​measured by the sensors 11, 12, and 21 are sent to the control device 100.

[0015] The TCA cooler 8 includes a heat exchanger 81 and a fan 82. The heat exchanger 81 exchanges heat between high-temperature compressed air extracted from the casing 6 and fuel (gas fuel or oil fuel). The fuel is heated by the heat exchange and supplied to the combustor 3 through the fuel system 7. Raising the fuel temperature improves the fuel combustion efficiency. The compressed air is cooled by the heat exchange and supplied to the turbine 4 as cooling air. The cooling air is used to cool the moving blades and stationary blades of the first and second stages of the turbine 4. While FIG. 1 illustrates an example in which cooling air is supplied to the turbine 4, the cooling air cooled by the TCA cooler 8 can also be supplied to a combustion liner (not shown) of the combustor 3 and used to cool the combustion liner. The fan 82 sends air to the heat exchanger 81 and adjusts the amount of heat exchange. The control device 100 controls the rotation speed of the fan 82 to control the temperature of the cooling air at the outlet of the TCA cooler 8 to a desired temperature. The TCA cooler 8 may include a plurality of fans 82 .

[0016] 2 is a functional block diagram showing an example of a control device according to an embodiment. The control device 100 has various functions for controlling the gas turbine 1, but only the functions related to this embodiment will be described here, and descriptions of other functions will be omitted. The control device 100 has a fuel switching unit 110, an IGV control unit 120, a load control unit 130, and a cooling control unit 140.

[0017] The fuel switching unit 110 selects either oil fuel or gas fuel and controls the switching device 9 so that the selected type of fuel is supplied to the fuel system 7. The user may instruct which of oil fuel and gas fuel to select, or the fuel switching unit 110 may receive a signal specifying the type of fuel from another device and switch in accordance with that signal. The fuel switching unit 110 outputs a fuel switching signal indicating whether fuel switching is in progress to the IGV control unit 120. The fuel switching unit 110 outputs the fuel switching signal and the type of fuel after switching to the cooling control unit 140. Fuel switching takes a certain amount of time, and during this switching time the fuel switching unit 110 outputs a fuel switching signal indicating that fuel switching is in progress, and at other times it outputs a fuel switching signal indicating that fuel switching is not in progress.

[0018] The IGV control unit 120 controls the opening degree of the IGV 10. The IGV control unit 120 changes the opening degree of the IGV 10 depending on the load of the gas turbine 1, the type of fuel supplied to the combustor 3, and the like. When the opening degree of the IGV 10 increases, the flow rate of air taken in by the compressor 2 increases, and when the opening degree of the IGV 10 decreases, the flow rate of air taken in by the compressor 2 decreases. Furthermore, when the fuel switching unit 110 switches the fuel from gas fuel to oil fuel or from oil fuel to gas fuel, the load control unit 130 controls the opening degree of the IGV 10 to be larger than when the gas turbine 1 is operated under the same conditions until the switching is completed.

[0019] The load control unit 130 controls the load (output value) of the gas turbine 1. For example, upon receiving a command signal to increase the load, the load control unit 130 increases the flow rate of fuel supplied to the combustor 3, or instructs the IGV control unit 120 to control the opening degree of the IGV 10 to an opening degree according to the load. Furthermore, when the fuel switching unit 110 switches the fuel from gas fuel to oil fuel or from oil fuel to gas fuel, the load control unit 130 controls the load of the gas turbine 1 to be constant until the switching is completed.

[0020] The cooling control unit 140 controls the TCA cooler 8. The cooling control unit 140 includes a signal acquisition unit 141, a fan rotation speed setting unit 142, and a fan control unit 143. The signal acquisition unit 141 acquires the temperatures measured by the temperature sensors 11 and 12, the output values ​​measured by the output sensor 21, the fuel switching signal, a signal indicating the type of fuel after switching (oil fuel or gas fuel), and a signal indicating the operating mode of the TCA cooler 8 (high temperature mode or low temperature mode).

[0021] The fan rotation speed setting unit 142 sets the rotation speed of the fan 82. A method for the fan rotation speed setting unit 142 to set the rotation speed of the fan 82 will be described next with reference to FIG. The fan control unit 143 operates the fan 82 at the rotation speed set by the fan rotation speed setting unit 142 .

[0022] FIG. 3 is a diagram illustrating an example of a setting logic for the fan rotation speed according to the embodiment. The fan rotation speed setting unit 142 includes a base rotation speed calculation unit 142a, a correction unit 142b, a feedback control execution determination unit 142c, a feedback correction amount calculation unit 142d, and a target temperature calculation unit 142e.

[0023] The basic rotation speed calculation unit 142a acquires the load of the gas turbine 1 (the output value measured by the output sensor 21) and the inlet temperature of the compressor 2 (the temperature measured by the temperature sensor 11), and calculates the rotation speed of the fan 82. For example, the basic rotation speed calculation unit 142a is provided with a function α that outputs the rotation speed of the fan 82 when the load of the gas turbine 1 and the inlet temperature of the compressor 2 are input, and the output value measured by the output sensor 21 and the temperature measured by the temperature sensor 11, which are acquired by the signal acquisition unit 141, are input to this function α. ​​The basic rotation speed calculation unit 142a outputs the rotation speed calculated by the function α to the correction unit 142b. When fuel switching does not occur or when the load is less than a predetermined threshold, the fan 82 is operated at the rotation speed output by the basic rotation speed calculation unit 142a.

[0024] The FB control execution determination unit 142c acquires the output value measured by the output sensor 21 and the fuel switching signal, and determines whether to use the rotation speed of the fan 82 as the rotation speed calculated by the basic rotation speed calculation unit 142a or to use a value obtained by adding a correction by feedback control (hereinafter, also referred to as FB control) to that rotation speed, and outputs the determined calculation method for the fan rotation speed to the FB correction amount calculation unit 142d. Specifically, (1) the FB control execution determination unit 142c determines to execute correction by feedback control if the load of the gas turbine 1 is equal to or greater than a predetermined threshold, for example, if the load of the gas turbine 1 is equal to or greater than 95% of the maximum load. (2) The FB control execution determination unit 142c determines to execute correction by feedback control if the fuel switching signal indicates that fuel switching is in progress. (3) The FB control execution determination unit 142c determines not to execute correction by feedback control in cases other than (1) and (2). The FB control execution determining unit 142c outputs the result of the determination, that is, whether or not to perform correction by feedback control, to the FB correction amount calculating unit 142d.

[0025] The FB correction amount calculation unit 142d acquires the decision of the FB control execution decision unit 142c, the outlet temperature of the TCA cooler 8, and the target value (referred to as target temperature) of the outlet temperature of the TCA cooler 8, and calculates a correction amount to be added to the rotation speed output by the basic rotation speed calculation unit 142a. If the FB control execution decision unit 142c decides not to execute correction by feedback control, the FB correction amount calculation unit 142d calculates 0 as the correction amount and outputs the correction amount 0 to the correction unit 142b. If the FB control execution decision unit 142c decides to execute correction by feedback control, the FB correction amount calculation unit 142d calculates a correction amount by PI control to make the outlet temperature of the TCA cooler 8 the target temperature. The FB correction amount calculation unit 142d calculates the deviation between the outlet temperature of the TCA cooler 8 (the temperature measured by the temperature sensor 12) and the target temperature output by the target temperature calculation unit 142e, and repeatedly performs a process at a predetermined cycle to calculate a correction amount for the fan rotation speed so as to make this deviation 0. The FB correction amount calculation unit 142d outputs the calculated correction amount for the fan rotation speed to achieve the target temperature to the correction unit 142b.

[0026] The target temperature calculation unit 142e acquires the compressor inlet temperature, the operation mode of the TCA cooler 8, and the type of fuel, and calculates a target value (target temperature) for the outlet temperature of the TCA cooler 8 based on this information. For example, the target temperature calculation unit 142e has a function β that outputs a target temperature at the outlet side of the TCA cooler 8 when the compressor inlet temperature, the operation mode (high temperature mode or low temperature mode) of the TCA cooler 8, and the type of fuel (oil fuel or gas fuel) are input. The temperature measured by the temperature sensor 11, the operation mode, and the type of fuel acquired by the signal acquisition unit 141 are input to this function β. The target temperature calculation unit 142e outputs the target temperature calculated by the function β to the FB correction amount calculation unit 142d. Note that the high temperature mode of the operation mode corresponds to an operating state of the gas turbine 1 in which the outlet temperature of the TCA cooler 8 should be kept high (an operating state in which the operating efficiency is desired to be maximized). For example, when the gas turbine 1 is operated at a high load, the high temperature mode is set as the operating mode. Conversely, the low temperature mode corresponds to an operating state of the gas turbine 1 in which the outlet temperature of the TCA cooler 8 is kept relatively low, and for example, the low temperature mode is set when the load on the gas turbine 1 is not high. The operating mode is set by the load control unit 130 and output to the cooling control unit 140.

[0027] FIG. 4 is a diagram for explaining control when the load of the gas turbine changes and when fuel is switched according to the embodiment. The graph in FIG. 4 shows an example of load change over time of the gas turbine 1. The vertical axis of the graph in FIG. 4 represents the load of the gas turbine 1, and the horizontal axis represents time. The load control unit 130 starts operation at T0 and gradually increases the load until T1. The control of this embodiment is applicable to both cases of switching from gas fuel to oil fuel and switching from oil fuel to gas fuel. Here, it is assumed that gas fuel is initially supplied to the combustor 3. The fuel switching unit 110 outputs a fuel switching signal indicating that fuel switching is not in progress. The fan rotation speed setting unit 142 outputs the rotation speed calculated by the basic rotation speed calculation unit 142a from the load and the inlet temperature of the compressor 2 to the fan control unit 143. The fan control unit 143 operates the fan 82 at a rotation speed commensurate with the load. It is assumed that the remaining amount of gas fuel becomes low at T1, causing switching from gas fuel to oil fuel. The fuel switching unit 110 controls the switching device 9 to switch the fuel supplied to the combustor 3 from gas fuel to oil fuel and changes the content of the fuel switching signal during fuel switching. The IGV control unit 120 then opens the IGV 10 to a larger opening than the opening determined by the fuel type, load, etc. when fuel switching is not in progress. Combustion oscillation is more likely to occur during fuel switching. The applicant has analyzed that this combustion oscillation is sensitive to the air flow rate passing through the combustor 3. To prevent combustion oscillation from occurring, the IGV control unit 120 increases the opening of the IGV 10 upon receiving a fuel switching signal indicating that fuel switching is in progress. For example, the degree of opening is set depending on the fuel type and load before and after switching, and the IGV control unit 120 increases the opening of the IGV 10 according to this setting. This reduces the likelihood of combustion oscillation.

[0028] However, increasing the opening of the IGV 10 increases the temperature of the compressed air at the outlet of the compressor 2, which in turn increases the temperature of the compressed air at the inlet of the TCA cooler 8. This also increases the air temperature at the outlet of the TCA cooler 8. The rotation speed calculated by the basic rotation speed calculation unit 142a is not based on the assumption that the IGV 10 is opened wider than normal. Therefore, when the IGV 10 is opened widely, the cooling air temperature cannot be controlled to the expected temperature and becomes high. Therefore, in the fan rotation speed setting unit 142, the FB control execution decision unit 142c decides to execute feedback control (PI control) based on the fuel switching signal. The target temperature calculation unit 142e calculates the target temperature of the cooling air. The FB correction amount calculation unit 142d calculates a correction amount to achieve this target temperature. The correction unit 142b then adds the correction amount to the rotation speed calculated by the basic rotation speed calculation unit 142a to determine the rotation speed of the fan 82. The fan control unit 143 operates the fan 82 at a rotation speed that reflects the results of the feed control.

[0029] The reason for not performing feedback control until T1 and controlling the fan 82 with a proactive rotation speed command value commensurate with the load is to prevent temperature overshoot, which could occur if the fan 82 were controlled solely by feedback control, as this would result in a control delay that would prevent the fan 82 from tracking load changes. Furthermore, the feedback control is based solely on the proactive rotation speed command value calculated by the base rotation speed calculation unit 142a and is intended to eliminate the deviation between the outlet temperature of the TCA cooler 8 calculated by the proactive rotation speed command value and the target temperature. Therefore, the problem of overshoot does not occur. However, feedback control cannot respond quickly and accurately to the outlet temperature of the TCA cooler 8, which changes in response to load changes. Therefore, the load control unit 130 controls the load of the gas turbine 1 to be constant during fuel switching. This suppresses an increase in the outlet temperature of the TCA cooler 8 and maintains it at the target temperature, even when the IGV 10 is controlled to a large opening during fuel switching.

[0030] Switching the fuel takes several tens of minutes to an hour. During this time, the IGV control unit 120 maintains the IGV 10 at a wide opening, the load control unit 130 controls the load change within a predetermined range to maintain a constant load, and the fan speed setting unit 142 sets the fan speed through feedback control. At T2, the fuel switching is completed. Once the fuel switching is complete, the fuel switching unit 110 changes the fuel switching signal to indicate that the fuel is not being switched. In response to the change in the fuel switching signal, the IGV control unit 120 returns the IGV 10 to the opening under normal control, and the fan speed setting unit 142 stops feedback control and outputs the speed calculated by the base speed calculation unit 142a to the fan control unit 143. The load control unit 130 then gradually increases the load again to the specified value.

[0031] Next, when the load exceeds a predetermined threshold (e.g., 95%) at T3, the feedback control execution decision unit 142c decides to execute feedback control. The feedback correction amount calculation unit 142d performs PI control based on the target temperature calculated by the target temperature calculation unit 142e and the outlet temperature of the TCA cooler 8 measured by the temperature sensor 12, and calculates a correction amount. At this time, the target temperature calculation unit 142e is input with a high-temperature mode, and a relatively high temperature is set as the target temperature. The correction unit 142b outputs a rotation speed command value obtained by adding a correction amount to the rotation speed calculated by the basic rotation speed calculation unit 142a to the fan control unit 143. In the high-load range, the gas turbine 1 operates as efficiently as possible to maximize its capabilities. Therefore, feedback control is also applied to the outlet temperature of the TCA cooler 8 to accurately control the temperature of the cooling air. Because the temperature does not change significantly under high-load conditions, control to maintain a constant load, as is done during fuel switching, is not performed. The opening of the IGV 10 is also controlled as usual.

[0032] While the above description has been given using an example of switching from gas fuel to oil fuel, the same applies when switching from oil fuel to gas fuel. Furthermore, if the fuel switching occurs when the load exceeds a threshold, the IGV 10 is opened widely to control the load change within a predetermined range. This applies not only to cases where the load is increased but also to cases where the load is decreased. That is, when the load of the gas turbine 1 is equal to or greater than a threshold, feedback control is performed regarding the target temperature on the outlet side of the TCA cooler 8. When the load is below the threshold, feedback control is not performed, and the fan 82 is controlled at the rotational speed calculated by the basic rotational speed calculation unit 142a. Furthermore, regardless of the load of the gas turbine 1, feedback control is performed regarding the target temperature on the outlet side of the TCA cooler 8 during fuel switching. Once the fuel switching is complete, feedback control is not performed, and the rotational speed calculated by the basic rotational speed calculation unit 142a is used. Furthermore, during fuel switching, the load reduction is temporarily suspended, the load is kept constant, and the IGV 10 is opened widely. Once the fuel switch is complete, the IGV 10 opening control is returned to normal control, and the load is reduced again. This makes it possible to control the outlet temperature of the TCA cooler 8 to the desired temperature even during load changes or fuel switchover, contributing to stable operation of the gas turbine 1.

[0033] (operation) Next, the operation of the control device 100 of this embodiment will be described. FIG. 5 is a flowchart showing an example of control according to the embodiment. The control device 100 determines whether or not fuel switching is in progress (step S1). If the fuel switching signal output from the fuel switching unit 110 indicates that fuel switching is in progress, the determination is Yes, and otherwise the determination is No.

[0034] If fuel switching is in progress (Step S1; Yes), the control device 100 performs control to maintain a large IGV opening and a constant load (Step S2). The IGV control unit 120 opens the IGV 10 widely, and the load control unit 130 controls the load to be constant by, for example, maintaining a constant fuel flow rate supplied to the combustor 3. The control device 100 also performs feedback control of the fan 82 (Step S3). This control is the control performed when the feedback control execution determination unit 142c determines to execute feedback control, as described with reference to FIG. 3. While FIG. 5 shows steps S2 and S3 in this order, the control device 100 may execute steps S2 and S3 simultaneously. As long as there is no significant difference in the time at which steps S2 and S3 are executed, the IGV opening control, constant load control, and fan speed control can be started in any order. Next, the control device 100 determines whether fuel switching is complete based on the fuel switching signal (Step S4). If the fuel switching is complete (step S4; Yes), the control device 100 ends the control of steps S2 and S3 and proceeds to the processing of step S5. If the fuel switching is not complete (step S4; No), the control device 100 continues the control of steps S2 and S3.

[0035] If fuel switching is not in progress (step S1; No), the control device 100 performs normal IGV opening and load control (step S5). Next, the control device 100 determines whether the load of the gas turbine 1 is equal to or greater than a threshold value (step S6). If the load of the gas turbine 1 is equal to or greater than the threshold value (step S6; Yes), the control device 100 controls the fan 82 with feedback control (step S7). This control is the control when the FB control execution determination unit 142c determines to execute feedback control, as described with reference to FIG. 3. If the load is less than the threshold value (step S6; No), the control device 100 performs normal control of the fan 82 (step S8). This control is the control when the FB control execution determination unit 142c determines not to execute feedback control, as described with reference to FIG. 3.

[0036] Next, the control device 100 determines whether to end the control (step S9). For example, if the operation of the gas turbine is to be stopped, the control device 100 determines to end the control, and otherwise determines to continue the control. If the control is to be ended (step S9; Yes), the processing of FIG. 5 is ended. If the control is to be continued (step S9; No), the processing from step S1 is repeated.

[0037] (effect) As described above, according to this embodiment, when a fuel switch occurs during operation of the gas turbine 1, the IGV opening is slightly increased, the load is kept constant, and the rotation speed of the fan 82 is controlled by control involving feedback control. This makes it possible to control the outlet temperature of the TCA cooler 8 to a desired temperature while avoiding the occurrence of combustion oscillation. Furthermore, once the fuel switch is completed, the IGV opening, load control, and fan 82 rotation speed control are returned to normal control. This enables stable control as in the past, even when a fuel switch occurs. Note that, in the above embodiment, an example has been described in which gas fuel and oil fuel are switched over, but the types of fuel are not limited to these. Furthermore, this embodiment can also be applied when the number of combustion types to be switched over is three or more.

[0038] 6 is a diagram showing an example of the hardware configuration of the control device 100 according to the embodiment. The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905. The above-described control device 100 is implemented in the computer 900. The above-described functions are stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, loads it into the main storage device 902, and executes the above-described processing in accordance with the program. The CPU 901 also allocates a storage area in the main storage device 902 in accordance with the program. The CPU 901 also allocates a storage area in the auxiliary storage device 903 for storing data being processed in accordance with the program.

[0039] A program for implementing all or part of the functions of the control device 100 may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed to perform processing by each functional unit. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, if a WWW system is used, the term "computer system" also includes a homepage provision environment (or display environment). Furthermore, the term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, as well as storage devices such as hard disks built into the computer system. Furthermore, if the program is distributed to the computer 900 via a communication line, the computer 900 that receives the program may load the program into the main storage device 902 and execute the above-described processing. Furthermore, the program may be for implementing part of the above-described functions, or may be capable of implementing the above-described functions in combination with a program already stored in the computer system.

[0040] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention.

[0041] <Additional Notes> The control device, gas turbine, control method, and program described in the embodiments can be understood, for example, as follows.

[0042] (1) A control device for a gas turbine including a compressor according to a first aspect, a combustor, a turbine section, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel supplied to the combustor, wherein the fuel supplied to the combustor is switched to one of a plurality of types of fuel, the control device including: a signal acquiring means that acquires a fuel switching signal indicating that the fuel supplied to the combustor is being switched; an inlet guide vane control means that controls an opening degree of an inlet guide vane of the compressor; and a means for controlling a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, by a control value corresponding to an output value of the gas turbine. and a cooling control means that switches between controlling the cooling temperature by a value obtained by adding the correction amount to the control value, and controlling the cooling temperature by a value obtained by controlling the cooling temperature by a value obtained by adding the correction amount to the control value, in accordance with an output value of the gas turbine, when the signal acquisition means acquires the fuel switching signal, the inlet guide vane control means increases the opening of the inlet guide vane, and the cooling control means executes the feedback control to control the cooling temperature by a value obtained by adding the correction amount to the control value. This allows the cooling temperature to be controlled to the target temperature when the fuel is switched.

[0043] (2) A control device according to a second aspect is the control device of (1), wherein the cooling control means does not execute the feedback control when the output value of the gas turbine is less than a predetermined threshold, executes the feedback control when the output value of the gas turbine is equal to or greater than the threshold, and executes the feedback control when the signal acquisition means acquires the fuel switching signal, even if the output value of the gas turbine is less than the threshold. As a result, by executing feedback control at the time of fuel switching, regardless of the load (output value) of the gas turbine, it is possible to control the cooling temperature at the time of fuel switching so that it becomes the target temperature.

[0044] (3) A control device according to a third aspect is a control device according to (1) to (2), further comprising an output control means for controlling the output value of the gas turbine, and when the signal acquisition means acquires a fuel switching signal, the output control means suppresses a change in the output value of the gas turbine within a predetermined range. This allows the cooling temperature to be controlled with high precision.

[0045] (4) A control device according to a fourth aspect is a control device of (1) to (3), wherein when the signal acquisition means stops acquiring the fuel switching signal, the cooling control means controls the cooling temperature using the control value corresponding to the output value of the gas turbine if the output value of the gas turbine is less than the threshold value, and performs the feedback control to control the cooling temperature using a value obtained by adding the correction amount to the control value if the output value of the gas turbine is equal to or greater than the threshold value. This allows normal control to be restored once the fuel switch is complete.

[0046] (5) A control device according to a fifth aspect is a control device of (1) to (4), wherein the cooling control means calculates the target value of the cooling temperature based on the inlet temperature of the compressor, the type of fuel, and setting information indicating whether the cooling temperature is to be high or low. This makes it possible to set a target value for the cooling temperature when switching fuel.

[0047] (6) A control device according to a sixth aspect is a control device according to any one of (1) to (5), wherein the cooling control means sets the control value based on an output value of the gas turbine and an inlet temperature of the compressor. This allows the control value (the rotation speed of the fan 82) to be calculated.

[0048] (7) A control device according to a seventh aspect is a control device of (1) to (6), wherein the cooler includes a heat exchanger that exchanges heat between a portion of the compressed air and the fuel, and a fan that blows air to the heat exchanger, and when the cooling control means controls the cooling temperature using a control value that corresponds to the output value of the gas turbine, the cooling control means calculates, as the control value, the rotation speed of the fan that corresponds to the output value of the gas turbine and the inlet temperature of the compressor. This allows the rotation speed of the fan to be calculated.

[0049] (8) A gas turbine according to an eighth aspect includes a compressor, a combustor capable of switching between and supplying one of a plurality of types of fuel, a turbine section, a cooler that performs heat exchange between a portion of the compressed air compressed by the compressor and the fuel supplied to the combustor, and a control device according to any one of (1) to (7).

[0050] (9) A control method according to a ninth aspect is a control method for a gas turbine including a compressor, a combustor, a turbine unit, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel to be supplied to the combustor, wherein the fuel to be supplied to the combustor is switched to one of a plurality of types of fuel, the control method comprising the steps of: acquiring a fuel switching signal indicating that the fuel to be supplied to the combustor is being switched; increasing an opening degree of an inlet guide vane of the compressor; executing feedback control based on a deviation between a target value of a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and a measured value of the cooling temperature; calculating a correction amount for achieving the target value of the cooling temperature; and controlling the cooling temperature with a value obtained by adding the correction amount to a control value corresponding to an output value of the gas turbine.

[0051] (10) A program according to a tenth aspect causes a computer to execute a process for controlling a gas turbine including a compressor, a combustor, a turbine unit, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel to be supplied to the combustor, wherein the fuel to be supplied to the combustor is switched to one of a plurality of types of fuel, the program acquiring a fuel switching signal indicating that the fuel to be supplied to the combustor is being switched, increasing an opening degree of an inlet guide vane of the compressor, executing feedback control based on a deviation between a target value of a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and a measured value of the cooling temperature, calculating a correction amount for achieving the target value of the cooling temperature, and controlling the cooling temperature with a value obtained by adding the correction amount to a control value corresponding to an output value of the gas turbine. [Explanation of symbols]

[0052] 1. Gas turbine 2. Compressor 3. Combustor 4. Turbine 5. Rotor 6...Car interior 7...Fuel system 8. TCA cooler (cooler) 81...heat exchanger 82...Fan 9. Switching device 10. IGV (Inlet Guide Vane) 11. Temperature sensor 12. Temperature sensor 20. Generator 21 Output sensor 100 Control device 110 Fuel switching section 120 IGV control unit 130 Load control section 140 Cooling control unit 141 Signal acquisition unit 142 Fan speed setting section 142a···Basic rotation speed calculation section 142b Correction section 142c: FB control execution decision section 142d...FB correction amount calculation section 142e...Target temperature calculation section 143 Fan control unit 900···Computer 901 CPU 902...Main memory 903...Auxiliary storage device 904 Input / Output Interface 905···Communication Interface

Claims

1. A control device for a gas turbine including a compressor, a combustor, a turbine unit, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel supplied to the combustor, the control device being capable of switching the fuel supplied to the combustor to one of a plurality of types of fuel, a signal acquiring means for acquiring a fuel switching signal indicating that the fuel to be supplied to the combustor is being switched; an inlet guide vane control means for controlling an opening degree of an inlet guide vane of the compressor; a cooling control means for controlling a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and for switching between controlling the cooling temperature by a control value corresponding to an output value of the gas turbine, or calculating a correction amount for achieving the target value of the cooling temperature by executing feedback control based on a deviation between a target value of the cooling temperature and a measured value of the cooling temperature, and controlling the cooling temperature by a value obtained by adding the correction amount to the control value, in accordance with the output value of the gas turbine; Equipped with When the signal acquisition means acquires the fuel switching signal, the inlet guide vane control means increases the opening degree of the inlet guide vane, the cooling control means executes the feedback control to control the cooling temperature based on a value obtained by adding the correction amount to the control value. Control device.

2. the cooling control means does not execute the feedback control when an output value of the gas turbine is less than a predetermined threshold, executes the feedback control when the output value of the gas turbine is equal to or greater than the threshold, and executes the feedback control when the signal acquisition means acquires the fuel switching signal even if the output value of the gas turbine is less than the threshold. The control device according to claim 1 .

3. further comprising an output control means for controlling an output value of the gas turbine, the output control means, when the signal acquisition means acquires the fuel switching signal, suppresses a change in the output value of the gas turbine within a predetermined range. The control device according to claim 1 or 2.

4. When the signal acquisition means no longer acquires the fuel switching signal, the cooling control means controls the cooling temperature by the control value corresponding to the output value of the gas turbine when the output value of the gas turbine is less than the threshold value, and executes the feedback control to control the cooling temperature by a value obtained by adding the correction amount to the control value when the output value of the gas turbine is equal to or greater than the threshold value. The control device according to claim 1 or 2.

5. the cooling control means calculates the target value of the cooling temperature based on the inlet temperature of the compressor, the type of fuel, and setting information indicating whether the cooling temperature is to be high or low. The control device according to claim 1 or 2.

6. the cooling control means calculates the control value based on an output value of the gas turbine and an inlet temperature of the compressor. The control device according to claim 1 or 2.

7. the cooler includes a heat exchanger that performs heat exchange between a portion of the compressed air and the fuel, and a fan that sends air to the heat exchanger, when the cooling control means controls the cooling temperature using a control value corresponding to an output value of the gas turbine, the cooling control means calculates, as the control value, a rotation speed of the fan based on the output value of the gas turbine and an inlet temperature of the compressor. The control device according to claim 1 or 2.

8. a compressor; a combustor capable of switching between and supplying any one of a plurality of types of fuel; a turbine unit; and a cooler that performs heat exchange between a portion of the compressed air compressed by the compressor and the fuel supplied to the combustor. The control device according to claim 1 or 2; A gas turbine comprising:

9. A control method for a gas turbine including a compressor, a combustor, a turbine unit, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel supplied to the combustor, wherein the fuel supplied to the combustor can be switched to any one of a plurality of types of fuel, the method comprising: When a fuel switching signal indicating that the fuel supplied to the combustor is being switched is obtained, Increasing the opening of the inlet guide vane of the compressor, executing feedback control based on a deviation between a target value of a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and a measured value of the cooling temperature, to calculate a correction amount for achieving the target value of the cooling temperature, and controlling the cooling temperature with a value obtained by adding the correction amount to a control value corresponding to an output value of the gas turbine. Control method.

10. On the computer, A process for controlling a gas turbine including a compressor, a combustor, a turbine unit, and a cooler that performs heat exchange between a portion of compressed air compressed by the compressor and fuel supplied to the combustor, the process being capable of switching the fuel supplied to the combustor to one of a plurality of types of fuel, the process comprising: obtaining a fuel switching signal indicating that the fuel supplied to the combustor is being switched; Increasing the opening of the inlet guide vane of the compressor, a process of executing feedback control based on a deviation between a target value of a cooling temperature, which is the temperature of the compressed air at an outlet side of the cooler, and a measured value of the cooling temperature, calculating a correction amount for achieving the target value of the cooling temperature, and controlling the cooling temperature with a value obtained by adding the correction amount to a control value corresponding to an output value of the gas turbine; A program that executes the following.

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